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Mancilla-Rojano J, Flores V, Cevallos MA, Ochoa SA, Parra-Flores J, Arellano-Galindo J, Xicohtencatl-Cortes J, Cruz-Córdova A. A bioinformatic approach to identify confirmed and probable CRISPR-Cas systems in the Acinetobacter calcoaceticus- Acinetobacter baumannii complex genomes. Front Microbiol 2024; 15:1335997. [PMID: 38655087 PMCID: PMC11035748 DOI: 10.3389/fmicb.2024.1335997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction The Acinetobacter calcoaceticus-Acinetobacter baumannii complex, or Acb complex, consists of six species: Acinetobacter baumannii, Acinetobacter calcoaceticus, Acinetobacter nosocomialis, Acinetobacter pittii, Acinetobacter seifertii, and Acinetobacter lactucae. A. baumannii is the most clinically significant of these species and is frequently related to healthcare-associated infections (HCAIs). Clustered regularly interspaced short palindromic repeat (CRISPR) arrays and associated genes (cas) constitute bacterial adaptive immune systems and function as variable genetic elements. This study aimed to conduct a genomic analysis of Acb complex genomes available in databases to describe and characterize CRISPR systems and cas genes. Methods Acb complex genomes available in the NCBI and BV-BRC databases, the identification and characterization of CRISPR-Cas systems were performed using CRISPRCasFinder, CRISPRminer, and CRISPRDetect. Sequence types (STs) were determined using the Oxford scheme and ribosomal multilocus sequence typing (rMLST). Prophages were identified using PHASTER and Prophage Hunter. Results A total of 293 genomes representing six Acb species exhibited CRISPR-related sequences. These genomes originate from various sources, including clinical specimens, animals, medical devices, and environmental samples. Sequence typing identified 145 ribosomal multilocus sequence types (rSTs). CRISPR-Cas systems were confirmed in 26.3% of the genomes, classified as subtypes I-Fa, I-Fb and I-Fv. Probable CRISPR arrays and cas genes associated with CRISPR-Cas subtypes III-A, I-B, and III-B were also detected. Some of the CRISPR-Cas systems are associated with genomic regions related to Cap4 proteins, and toxin-antitoxin systems. Moreover, prophage sequences were prevalent in 68.9% of the genomes. Analysis revealed a connection between these prophages and CRISPR-Cas systems, indicating an ongoing arms race between the bacteria and their bacteriophages. Furthermore, proteins associated with anti-CRISPR systems, such as AcrF11 and AcrF7, were identified in the A. baumannii and A. pittii genomes. Discussion This study elucidates CRISPR-Cas systems and defense mechanisms within the Acb complex, highlighting their diverse distribution and interactions with prophages and other genetic elements. This study also provides valuable insights into the evolution and adaptation of these microorganisms in various environments and clinical settings.
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Affiliation(s)
- Jetsi Mancilla-Rojano
- Posgrado en Ciencias Biológicas, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico, Mexico
- Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Mexico, Mexico
| | - Víctor Flores
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Miguel A. Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sara A. Ochoa
- Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Mexico, Mexico
| | - Julio Parra-Flores
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán, Chile
| | - José Arellano-Galindo
- Unidad de Investigación en Enfermedades Infecciosas, Hospital Infantil de México Federico Gomez, Mexico, Mexico
| | - Juan Xicohtencatl-Cortes
- Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Mexico, Mexico
| | - Ariadnna Cruz-Córdova
- Posgrado en Ciencias Biológicas, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico, Mexico
- Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Mexico, Mexico
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Lozano-Aguirre L, Avitia M, Lappe-Oliveras P, Licona-Cassani C, Cevallos MA, Le Borgne S. Draft genomes of four Kluyveromyces marxianus isolates retrieved from the elaboration process of henequen ( Agave fourcroydes) mezcal. Microbiol Resour Announc 2024; 13:e0086123. [PMID: 38294215 DOI: 10.1128/mra.00861-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/15/2024] [Indexed: 02/01/2024] Open
Abstract
We report the draft genomes of four Kluyveromyces marxianus isolates obtained from the elaboration process of henequen (Agave fourcroydes) mezcal, a Mexican alcoholic beverage. The average nucleotide identity analysis revealed that isolates derived from agave plants are distinct from those from other environments, including agave fermentations.
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Affiliation(s)
- Luis Lozano-Aguirre
- Unidad de Análisis Bioinformáticos, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Morena Avitia
- Laboratorio Nacional de Ciencias de la Sostenibilidad (LANCIS), Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Patricia Lappe-Oliveras
- Laboratorio de Micromicetos, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Cuauhtémoc Licona-Cassani
- Laboratorio de Genómica Industrial, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Monterrey, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sylvie Le Borgne
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Unidad Cuajimalpa, Ciudad de México, Mexico
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Bello-López E, Escobedo-Muñoz AS, Hernández-Castro R, Cevallos MA. Genome sequence of an Acinetobacter pittii strain obtained from a red -lored parrot with pneumonia. Microbiol Resour Announc 2024; 13:e0103823. [PMID: 38112472 DOI: 10.1128/mra.01038-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023] Open
Abstract
Acinetobacter pittii 978-A_19 was obtained from a parrot with pneumonia. It is resistant to ampicillin, carbenicillin, cephalosporins, clindamycin, and trimethoprim + sulfamethoxazole. The genome encodes a new blaADC allele, a blaOXA-502 gene, possesses several virulence genes related to adherence and biofilm formation, and has types I, II, and IV secretion systems.
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Affiliation(s)
- E Bello-López
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México , Cuernavaca, Morelos, Mexico
| | - A S Escobedo-Muñoz
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México , Cuernavaca, Morelos, Mexico
| | - R Hernández-Castro
- Departmento de Ecología de Patógenos, Hospital General Dr. Manuel Gea González , Ciudad de México, Mexico
| | - M A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México , Cuernavaca, Morelos, Mexico
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Nemec A, Španělová P, Shestivska V, Radolfová-Křížová L, Maixnerová M, Feng Y, Qin J, Cevallos MA, Zong Z. Proposal for Acinetobacter higginsii sp. nov. to accommodate organisms of human clinical origin previously classified as Acinetobacter genomic species 16. Int J Syst Evol Microbiol 2023; 73. [PMID: 37889259 DOI: 10.1099/ijsem.0.006114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Abstract
In 1989, Bouvet and Jeanjean delineated five proteolytic genomic species (GS) of Acinetobacter, each with two to four human isolates. Three were later validly named, whereas the remaining two (GS15 and GS16) have been awaiting nomenclatural clarification. Here we present the results of the genus-wide taxonomic study of 13 human strains classified as GS16 (n=10) or GS15 (n=3). Based on core genome phylogenetic analysis, the strains formed two respective but closely related phylogroups within the Acinetobacter haemolytic clade. The intraspecies genomic average nucleotide identity based on blast (ANIb) values for GS16 and GS15 reached ≥94.9 % and ≥98.7, respectively, whereas ANIb values between them were 92.5-93.5% and those between them and the known species were ≤91.5 %. GS16 and GS15 could be differentiated from the other Acinetobacter species by their ability to lyse gelatin and sheep blood and to assimilate d,l-lactate, along with their inability to acidify d-glucose and assimilate glutarate. In contrast, GS16 and GS15 were indistinguishable from one another by metabolic/physiological features or whole-cell MALDI-TOF mass spectra. All the GS15/GS16 genomes contained genes encoding a class D β-lactamase, Acinetobacter-derived cephalosporinase and aminoglycoside 6'-N-acetyltransferase. Searching NCBI databases revealed genome sequences of three additional isolates of GS16, but none of GS15. We conclude that our data support GS16 as representing a novel species, but leave the question of the taxonomic status of GS15 open, given its close relatedness to GS16 and the small number of available strains. We propose the name Acinetobacter higginsii sp. nov. for GS16, with the type strain NIPH 1872T (CCM 9243T=CIP 70.18T=ATCC 17988T).
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Affiliation(s)
- Alexandr Nemec
- Laboratory of Bacterial Genetics, National Institute of Public Health, Srobarova 48, 100 00 Prague 10, Czech Republic
- Department of Medical Microbiology, Charles University, 2nd Faculty of Medicine and Motol University Hospital, Prague, V Úvalu 84, 150 06 Prague 5, Czech Republic
| | - Petra Španělová
- Czech National Collection of Type Cultures, National Institute of Public Health, Šrobárova 48, 100 00 Prague 10, Czech Republic
| | - Violetta Shestivska
- Laboratory of Bacterial Genetics, National Institute of Public Health, Srobarova 48, 100 00 Prague 10, Czech Republic
| | - Lenka Radolfová-Křížová
- Laboratory of Bacterial Genetics, National Institute of Public Health, Srobarova 48, 100 00 Prague 10, Czech Republic
| | - Martina Maixnerová
- Laboratory of Bacterial Genetics, National Institute of Public Health, Srobarova 48, 100 00 Prague 10, Czech Republic
| | - Yu Feng
- Center of Infectious Diseases, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Center for Pathogen Research, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
| | - Jiayuan Qin
- Center of Infectious Diseases, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Center for Pathogen Research, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Zhiyong Zong
- Center of Infectious Diseases, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Division of Infectious Diseases, State Key Laboratory of Biotherapy, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
- Center for Pathogen Research, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, Sichuan, PR China
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Cevallos MA, Basanta MD, Bello-López E, Escobedo-Muñoz AS, González-Serrano FM, Nemec A, Romero-Contreras YJ, Serrano M, Rebollar EA. Genomic characterization of antifungal Acinetobacter bacteria isolated from the skin of the frogs Agalychnis callidryas and Craugastor fitzingeri. FEMS Microbiol Ecol 2022; 98:6775075. [PMID: 36288213 DOI: 10.1093/femsec/fiac126] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/09/2022] [Accepted: 10/24/2022] [Indexed: 01/21/2023] Open
Abstract
Chytridiomycosis, a lethal fungal disease caused by Batrachochytrium dendrobatidis (Bd), is responsible for population declines and extinctions of amphibians worldwide. However, not all amphibian species are equally susceptible to the disease; some species persist in Bd enzootic regions with no population reductions. Recently, it has been shown that the amphibian skin microbiome plays a crucial role in the defense against Bd. Numerous bacterial isolates with the capacity to inhibit the growth of Batrachochytrium fungi have been isolated from the skin of amphibians. Here, we characterized eight Acinetobacter bacteria isolated from the frogs Agalychnis callidryas and Craugastor fitzingeri at the genomic level. A total of five isolates belonged to Acinetobacter pittii,Acinetobacter radioresistens, or Acinetobactermodestus, and three were not identified as any of the known species, suggesting they are members of new species. We showed that seven isolates inhibited the growth of Bd and that all eight isolates inhibited the growth of the phytopathogen fungus Botrytis cinerea. Finally, we identified the biosynthetic gene clusters that could be involved in the antifungal activity of these isolates. Our results suggest that the frog skin microbiome includes Acinetobacter isolates that are new to science and have broad antifungal functions, perhaps driven by distinct genetic mechanisms.
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Affiliation(s)
- M A Cevallos
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - M D Basanta
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México.,Department of Biology, University of Nevada Reno, 1664 N Virgina St, Reno, NV 89557, United States
| | - E Bello-López
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - A S Escobedo-Muñoz
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - F M González-Serrano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - A Nemec
- Laboratory of Bacterial Genetics, Centre for Epidemiology and Microbiology, National Institute of Public Health, Šrobárova 48, 100 00 Prague 10, Czechia.,Department of Medical Microbiology, Second Faculty of Medicine, Charles University, and Motol University Hospital, V Úvalu 84, 150 06 Prague 5, Czechia
| | - Y J Romero-Contreras
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - M Serrano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
| | - E A Rebollar
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Avenida Universidad s/n, Cuernavaca, Morelos, 62220, México
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6
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Castro-Jaimes S, Guerrero G, Bello-López E, Cevallos MA. Replication initiator proteins of Acinetobacter baumannii plasmids: An update note. Plasmid 2021; 119-120:102616. [PMID: 34953823 DOI: 10.1016/j.plasmid.2021.102616] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 11/26/2022]
Abstract
The bioinformatic analysis that we made of 492 Acinetobacter baumannii plasmid sequences identified 418 genes encoding Replication Initiator (Rep) proteins that fell into at least fourteen groups according to the protein domains that they contained. The most abundant group of Rep proteins contained a Rep_3 superfamily domain, followed by Rep proteins containing Replicase/PriCT_1 superfamily domains, and then by Reps possessing only an HTH_MerR-SF superfamily domain. The remaining eleven groups contain only a few members. To evaluate the diversity of these Rep proteins, we classify them using the current scheme of GR homology groups, which contains 34 groups. However, we needed to create 22 additional GR homology groups to capture all the Rep protein diversity of the plasmid collection. Finally, our bioinformatic analysis suggests that a large fraction of the plasmids seem to have a restricted host range limited to Acinetobacter species, except for those belonging to GR38 that have a very wide host range. To facilitate the future analysis of the Rep proteins, we included a list of the DNA and protein sequences, in fasta format, of the representatives of each one of the GR homology groups.
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Affiliation(s)
- Semiramis Castro-Jaimes
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca CP62210, Morelos, Mexico
| | - Gabriela Guerrero
- Unidad de Análisis Bioinformático, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca CP62210, Morelos, Mexico
| | - Elena Bello-López
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca CP62210, Morelos, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca CP62210, Morelos, Mexico.
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López-Leal G, Reyes-Muñoz A, Santamaria RI, Cevallos MA, Pérez-Monter C, Castillo-Ramírez S. A novel vieuvirus from multidrug-resistant Acinetobacter baumannii. Arch Virol 2021; 166:1401-1408. [PMID: 33635432 DOI: 10.1007/s00705-021-05010-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 02/16/2021] [Indexed: 11/26/2022]
Abstract
Bacteriophages are considered the most abundant biological entities on earth, and they are able to modulate the populations of their bacterial hosts. Although the potential of bacteriophages has been accepted as an alternative strategy to combat multidrug-resistant pathogenic bacteria, there still exists a considerable knowledge gap regarding their genetic diversity, which hinders their use as antimicrobial agents. In this study, we undertook a genomic and phylogenetic characterization of the phage Ab11510-phi, which was isolated from a multidrug-resistant Acinetobacter baumannii strain (Ab11510). We found that Ab11510-phi has a narrow host range and belongs to a small group of transposable phages of the genus Vieuvirus that have only been reported to infect Acinetobacter bacteria. Finally, we showed that Ab11510-phi (as well as other vieuvirus phages) has a high level of mosaicism. On a broader level, we demonstrate that comparative genomics and phylogenetic analysis are necessary tools for the proper characterization of phage diversity.
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Affiliation(s)
- Gamaliel López-Leal
- Grupo de Biología Computacional y Ecología Microbiana, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, D.C., Colombia.
| | - Alejandro Reyes-Muñoz
- Grupo de Biología Computacional y Ecología Microbiana, Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, D.C., Colombia
| | - Rosa Isela Santamaria
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Carlos Pérez-Monter
- Departamento de Gastroenterología, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, México City, México
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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Mancilla-Rojano J, Ochoa SA, Reyes-Grajeda JP, Flores V, Medina-Contreras O, Espinosa-Mazariego K, Parra-Ortega I, Rosa-Zamboni DDL, Castellanos-Cruz MDC, Arellano-Galindo J, Cevallos MA, Hernández-Castro R, Xicohtencatl-Cortes J, Cruz-Córdova A. Molecular Epidemiology of Acinetobacter calcoaceticus- Acinetobacter baumannii Complex Isolated From Children at the Hospital Infantil de México Federico Gómez. Front Microbiol 2020; 11:576673. [PMID: 33178158 PMCID: PMC7593844 DOI: 10.3389/fmicb.2020.576673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/08/2020] [Indexed: 12/13/2022] Open
Abstract
The Acinetobacter calcoaceticus-baumannii (Acb) complex is regarded as a group of phenotypically indistinguishable opportunistic pathogens responsible for mainly causing hospital-acquired pneumonia and bacteremia. The aim of this study was to determine the frequency of isolation of the species that constitute the Acb complex, as well as their susceptibility to antibiotics, and their distribution at the Hospital Infantil de Mexico Federico Gomez (HIMFG). A total of 88 strains previously identified by Vitek 2®, 40 as Acinetobacter baumannii and 48 as Acb complex were isolated from 52 children from 07, January 2015 to 28, September 2017. A. baumannii accounted for 89.77% (79/88) of the strains; Acinetobacter pittii, 6.82% (6/88); and Acinetobacter nosocomialis, 3.40% (3/88). Most strains were recovered mainly from patients in the intensive care unit (ICU) and emergency wards. Blood cultures (BC) provided 44.32% (39/88) of strains. The 13.63% (12/88) of strains were associated with primary bacteremia, 3.4% (3/88) with secondary bacteremia, and 2.3% (2/88) with pneumonia. In addition, 44.32% (39/88) were multidrug-resistant (MDR) strains and, 11.36% (10/88) were extensively drug-resistant (XDR). All strains amplified the blaOXA-51 gene; 51.13% (45/88), the blaOXA-23 gene; 4.54% (4/88), the blaOXA-24 gene; and 2.27% (2/88), the blaOXA-58 gene. Plasmid profiles showed that the strains had 1–6 plasmids. The strains were distributed in 52 pulsotypes, and 24 showed identical restriction patterns, with a correlation coefficient of 1.0. Notably, some strains with the same pulsotype were isolated from different patients, wards, or years, suggesting the persistence of more than one clone. Twenty-seven sequence types (STs) were determined for the strains based on a Pasteur multilocus sequence typing (MLST) scheme using massive sequencing; the most prevalent was ST 156 (27.27%, 24/88). The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas I-Fb system provided amplification in A. baumannii and A. pittii strains (22.73%, 20/88). This study identified an increased number of MDR strains and the relationship among strains through molecular typing. The data suggest that more than one strain could be causing an infection in some patient. The implementation of molecular epidemiology allowed the characterization of a set of strains and identification of different attributes associated with its distribution in a specific environment.
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Affiliation(s)
- Jetsi Mancilla-Rojano
- Laboratorio de Investigación en Bacteriología Intestinal, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico.,Facultad de Medicina, Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, CDMX, Mexico
| | - Sara A Ochoa
- Laboratorio de Investigación en Bacteriología Intestinal, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | - Juan Pablo Reyes-Grajeda
- Subdirección de Desarrollo de Aplicaciones Clínicas, Instituto Nacional de Medicina Genómica, Ciudad de México, Mexico
| | - Víctor Flores
- Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Irapuato, Mexico
| | - Oscar Medina-Contreras
- Unidad de Investigación Epidemiológica en Endocrinología y Nutrición, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | - Karina Espinosa-Mazariego
- Laboratorio de Investigación en Bacteriología Intestinal, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | - Israel Parra-Ortega
- Departamento de Laboratorio Clínico, Laboratorio Central, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | | | | | - José Arellano-Galindo
- Unidad de investigación en Enfermedades Infecciosas, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | - Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | | | - Juan Xicohtencatl-Cortes
- Laboratorio de Investigación en Bacteriología Intestinal, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico
| | - Ariadnna Cruz-Córdova
- Laboratorio de Investigación en Bacteriología Intestinal, Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, CDMX, Mexico
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Salgado-Camargo AD, Castro-Jaimes S, Gutierrez-Rios RM, Lozano LF, Altamirano-Pacheco L, Silva-Sanchez J, Pérez-Oseguera Á, Volkow P, Castillo-Ramírez S, Cevallos MA. Structure and Evolution of Acinetobacter baumannii Plasmids. Front Microbiol 2020; 11:1283. [PMID: 32625185 PMCID: PMC7315799 DOI: 10.3389/fmicb.2020.01283] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/20/2020] [Indexed: 11/24/2022] Open
Abstract
Acinetobacter baumannii is an emergent bacterial pathogen that provokes many types of infections in hospitals around the world. The genome of this organism consists of a chromosome and plasmids. These plasmids vary over a wide size range and many of them have been linked to the acquisition of antibiotic-resistance genes. Our bioinformatic analyses indicate that A. baumannii plasmids belong to a small number of plasmid lineages. The general structure of these lineages seems to be very stable and consists not only of genes involved in plasmid maintenance functions but of gene sets encoding poorly characterized proteins, not obviously linked to survival in the hospital setting, and opening the possibility that they improve the parasitic properties of plasmids. An analysis of genes involved in replication, suggests that members of the same plasmid lineage are part of the same plasmid incompatibility group. The same analysis showed the necessity of classifying the Rep proteins in ten new groups, under the scheme proposed by Bertini et al. (2010). Also, we show that some plasmid lineages have the potential capacity to replicate in many bacterial genera including those embracing human pathogen species, while others seem to replicate only within the limits of the Acinetobacter genus. Moreover, some plasmid lineages are widely distributed along the A. baumannii phylogenetic tree. Despite this, a number of them lack genes involved in conjugation or mobilization functions. Interestingly, only 34.6% of the plasmids analyzed here possess antibiotic resistance genes and most of them belong to fourteen plasmid lineages of the twenty one described here. Gene flux between plasmid lineages appears primarily limited to transposable elements, which sometimes carry antibiotic resistance genes. In most plasmid lineages transposable elements and antibiotic resistance genes are secondary acquisitions. Finally, broad host-range plasmids appear to have played a crucial role.
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Affiliation(s)
- Abraham D Salgado-Camargo
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Semiramis Castro-Jaimes
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Rosa-Maria Gutierrez-Rios
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Luis F Lozano
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Luis Altamirano-Pacheco
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Jesús Silva-Sanchez
- Grupo de Resistencia Bacteriana, Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Mexico
| | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Patricia Volkow
- Departamento de Infectología, Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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10
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Cevallos MA, Guerrero G, Ríos S, Arroyo A, Villalobos MA, Porta H. The mitogenome of Pseudocrossidium replicatum, a desiccation-tolerant moss. Mitochondrial DNA B Resour 2020; 5:2339-2341. [PMID: 33457783 PMCID: PMC7782723 DOI: 10.1080/23802359.2020.1774436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Bryophytes are the earliest plant group on Earth. They are a fundamental component of many ecosystems around the World. Some of their main roles are related to soil development, water retention, and biogeochemical cycling. Bryophytes include liverworts, hornworts, and mosses. The sequencing of chloroplast and mitochondria genomes has been useful to elucidate the taxonomy of this heterogeneous plant group. To date, despite their ecological importance only 41 mosses mitogenomes have been deposited in the GenBank. Here, the complete mitochondria genome sequence of Pseudocrossidium replicatum, a moss of the Pottiaceae family isolated in Tlaxcala, Mexico, is reported. The mitochondrial genome size of P. replicatum comprises 105,495 bp and contains the groups of genes described for other bryophytes mitogenomes. Our phylogenetic analysis shows that during the evolution of the mosses’ mitogenome, nad7, rps4, rpl16, and rpl10 genes were lost independently in several lineages. The complete mitogenome sequence reported here would be a useful tool for our comprehension of the evolutionary and population genetics of this group of plants.
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Affiliation(s)
- Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P., México
| | - Gabriela Guerrero
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, C.P., México
| | - Selma Ríos
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Tepetitla de Lardizábal, Tlaxcala, C.P., México
| | - Analilia Arroyo
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Tepetitla de Lardizábal, Tlaxcala, C.P., México
| | - Miguel Angel Villalobos
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional. Tepetitla de Lardizábal, Tlaxcala, C.P., México
| | - Helena Porta
- Instituto de Biotecnología, Departamento de Biología Molecular de Plantas, Universidad Nacional Autónoma de México, Morelos, C.P., México
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11
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Arredondo-Hernández R, Schmulson M, Orduña P, López-Leal G, Zarate AM, Alanis-Funes G, Alcaraz LD, Santiago-Cruz R, Cevallos MA, Villa AR, Ponce-de-León Rosales S, López-Vidal Y. Mucosal Microbiome Profiles Polygenic Irritable Bowel Syndrome in Mestizo Individuals. Front Cell Infect Microbiol 2020; 10:72. [PMID: 32266159 PMCID: PMC7098960 DOI: 10.3389/fcimb.2020.00072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/13/2020] [Indexed: 01/08/2023] Open
Abstract
Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal disorder, worldwide, with a high prevalence among Mestizo Latin Americans. Because several inflammatory disorders appear to affect this population, a further understanding of host genomic background variants, in conjunction with colonic mucosa dysbiosis, is necessary to determine IBS physiopathology and the effects of environmental pressures. Using a simple polygenic model, host single nucleotide polymorphisms (SNPs) and the taxonomic compositions of microbiota were compared between IBS patients and healthy subjects. As proof of concept, five IBS-Rome III patients and five healthy controls (HCs) were systematically studied. The human and bacterial intestinal metagenome of each subject was taxonomically annotated and screened for previously annotated IBS, ulcerative colitis, and Crohn's disease-associated SNPs or taxon abundance. Dietary data and fecal markers were collected and associated with the intestinal microbiome. However, more than 1,000 variants were found, and at least 76 SNPs differentiated IBS patients from HCs, as did associations with 4 phyla and 10 bacterial genera. In this study, we found elements supporting a polygenic background, with frequent variants, among the Mestizo population, and the colonic mucosal enrichment of Bacteroides, Alteromonas, Neisseria, Streptococcus, and Microbacterium, may serve as a hallmark for IBS.
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Affiliation(s)
- Rene Arredondo-Hernández
- Laboratorio de Microbioma, División de Estudios de Posgrado y División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Max Schmulson
- Laboratorio de Hígado, Páncreas y Motilidad (HIPAM), Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Patricia Orduña
- Laboratorio de Microbioma, División de Estudios de Posgrado y División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gamaliel López-Leal
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Gerardo Alanis-Funes
- Tecnologico de Monterrey, School of Medicine and Health Sciences, Monterrey, Mexico
| | - Luis David Alcaraz
- Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Rubí Santiago-Cruz
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Antonio R Villa
- Laboratorio de Microbioma, División de Estudios de Posgrado y División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Samuel Ponce-de-León Rosales
- Laboratorio de Microbioma, División de Estudios de Posgrado y División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Yolanda López-Vidal
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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12
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Barrios-Villa E, Martínez de la Peña CF, Lozano-Zaraín P, Cevallos MA, Torres C, Torres AG, Rocha-Gracia RDC. Comparative genomics of a subset of Adherent/Invasive Escherichia coli strains isolated from individuals without inflammatory bowel disease. Genomics 2019; 112:1813-1820. [PMID: 31689478 DOI: 10.1016/j.ygeno.2019.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 09/05/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023]
Abstract
There is increased evidence demonstrating the association between Crohn's Disease (CD), a type of Inflammatory Bowel Disease (IBD), and non-diarrheagenic Adherent/Invasive Escherichia coli (AIEC) isolates. AIEC strains are phenotypically characterized by their adhesion, invasion and intra-macrophage survival capabilities. In the present study, the genomes of five AIEC strains isolated from individuals without IBD (four from healthy donors and one from peritoneal liquid) were sequenced and compared with AIEC prototype strains (LF82 and NRG857c), and with extra-intestinal uropathogenic strain (UPEC CFT073). Non-IBD-AIEC strains showed an Average Nucleotide Identity up to 98% compared with control strains. Blast identities of the five non-IBD-AIEC strains were higher when compared to AIEC and UPEC reference strains than with another E. coli pathotypes, suggesting a relationship between them. The SNPs phylogeny grouped the five non-IBD-AIEC strains in one separated cluster, which indicates the emergence of these strains apart from the AIEC group. Additionally, four genomic islands not previously reported in AIEC strains were identified. An incomplete Type VI secretion system was found in non-IBD-AIEC strains; however, the Type II secretion system was complete. Several groups of genes reported in AIEC strains were searched in the five non-IBD-AIEC strains, and the presence of fimA, fliC, fuhD, chuA, irp2 and cvaC were confirmed. Other virulence factors were detected in non-IBD-AIEC strains, which were absent in AIEC reference strains, including EhaG, non-fimbrial adhesin 1, PapG, F17D-G, YehA/D, FeuC, IucD, CbtA, VgrG-1, Cnf1 and HlyE. Based on the differences in virulence determinants and SNPs, it is plausible to suggest that non-IBD AIEC strains belong to a different pathotype.
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Affiliation(s)
- Edwin Barrios-Villa
- Posgrado en Microbiología, Laboratorio de Microbiología Hospitalaria y de la Comunidad, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Claudia Fabiola Martínez de la Peña
- Posgrado en Microbiología, Laboratorio de Biología Molecular de Enteropatógenos, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Patricia Lozano-Zaraín
- Posgrado en Microbiología, Laboratorio de Microbiología Hospitalaria y de la Comunidad, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Carmen Torres
- Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Rosa Del Carmen Rocha-Gracia
- Posgrado en Microbiología, Laboratorio de Microbiología Hospitalaria y de la Comunidad, Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico.
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13
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Mayoral-Terán C, Flores-Moreno K, Cevallos MA, Volkow-Fernández P, Castillo-Ramírez S, Graña-Miraglia L, López-Vidal Y. High Phenotypic and Genotypic Diversity of Enterococcus faecium from Clinical and Commensal Isolates in Third Level Hospital. Microb Drug Resist 2019; 26:227-237. [PMID: 31545121 DOI: 10.1089/mdr.2019.0039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: The use of antimicrobials and myeloablative chemotherapy regimens has promoted multiresistant microorganisms to emerge as nosocomial pathogens, such as vancomycin-resistant Enterococcus faecium (VREfm). We described a polyclonal outbreak of bloodstream infection caused by Efm in a hemato-oncological ward in Mexico. Our aim was to describe the clonal complex (CC) of the Efm strains isolated in the outbreak in comparison with commensal and environmental isolates. Methodology: Sixty Efm clinical, environmental, and commensal strains were included. We constructed a cladogram and a phylogenetic tree using Vitek and Multilocus sequence typing data, respectively. Results: We reported 20 new sequence types (ST), among which 17/43 clinical isolates belonged to CC17. The predominant ST in the clinical strains were ST757, ST1304, ST412, and ST770. Neither environmental nor commensal isolates belonged to CC17. The phylogeny of our collection shows that the majority of the clinical isolates were different from the environmental and commensal isolates, and only a small group of clinical isolates was closely related with environmental and commensal isolates. The cladogram revealed a similar segregation to that of the phylogeny. Conclusions: We found a high diversity among clinical, environmental, and commensal strains in a group of samples in a single hospital. Highest diversity was found between commensal and environmental isolates.
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Affiliation(s)
- Claudia Mayoral-Terán
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México-Ciudad Universitaria, Mexico City, Mexico
| | - Karen Flores-Moreno
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México-Ciudad Universitaria, Mexico City, Mexico
| | - Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, UNAM, Mexico City, Mexico
| | | | | | - Lucia Graña-Miraglia
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, UNAM, Mexico City, Mexico
| | - Yolanda López-Vidal
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México-Ciudad Universitaria, Mexico City, Mexico
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14
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Cevallos MA, Guerrero G, Ríos S, Arroyo A, Villalobos MA, Porta H. The chloroplast genome of the desiccation-tolerant moss Pseudocrossidium replicatum (Taylor) R.H. Zander. Genet Mol Biol 2019; 42:488-493. [PMID: 31323081 PMCID: PMC6726147 DOI: 10.1590/1678-4685-gmb-2018-0184] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/14/2018] [Indexed: 11/29/2022] Open
Abstract
Mosses in conjunction with hornworts and liverworts are collectively referred to
as bryophytes. These seedless, nonvascular plants are the closest extant
relatives of early terrestrial plants and their study is essential to understand
the evolutionary first steps of land plants. Here we report the complete
chloroplast (cp) genome sequence of Pseudocrossidium
replicatum, a moss belonging to the Pottiaceae family that is
common in the central highlands of Mexico, in South America, in southern USA,
and in Kenia. The cp genome (plastome) of P. replicatum is
123,512 bp in size, comprising inverted repeats of 9,886 bp and single-copy
regions of 85,146 bp (LSC) and 18,594 bp (SSC). The plastome encodes 82
different proteins, 31 different tRNAs, and 4 different rRNAs. Phylogenetic
analysis using 16 cp protein-coding genes demonstrated that P.
replicatum is closely related to Syntrichia
ruralis, and the most basal mosses are Takakia
lepidozioides followed by Sphagnum palustre. Our
analysis indicates that during the evolution of the mosses’ plastome, eight
genes were lost. The complete plastome sequence reported here can be useful in
evolutionary and population genetics.
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Affiliation(s)
- Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Gabriela Guerrero
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Selma Ríos
- Centro de Investigación en Biotecnología Aplicada, Laboratorio de Biología Molecular y Biotecnología de Plantas, Instituto Politécnico Nacional. Tepetitla de Lardizabal, Tlaxcala, Mexico
| | - Analilia Arroyo
- Centro de Investigación en Biotecnología Aplicada, Laboratorio de Biología Molecular y Biotecnología de Plantas, Instituto Politécnico Nacional. Tepetitla de Lardizabal, Tlaxcala, Mexico
| | - Miguel Angel Villalobos
- Centro de Investigación en Biotecnología Aplicada, Laboratorio de Biología Molecular y Biotecnología de Plantas, Instituto Politécnico Nacional. Tepetitla de Lardizabal, Tlaxcala, Mexico
| | - Helena Porta
- Instituto de Biotecnología, Departamento de Biología Molecular de Plantas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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15
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López-Leal G, Zuniga-Moya JC, Castro-Jaimes S, Graña-Miraglia L, Pérez-Oseguera Á, Reyes-García HS, Gough-Coto SD, Pavón-Madrid R, Bejarano SA, Ferrera A, Castillo-Ramírez S, Cevallos MA. Unexplored Genetic Diversity of Multidrug- and Extremely Drug-Resistant Acinetobacter baumannii Isolates from Tertiary Hospitals in Honduras. Microb Drug Resist 2019; 25:690-695. [DOI: 10.1089/mdr.2018.0311] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Gamaliel López-Leal
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | - Semiramis Castro-Jaimes
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Lucía Graña-Miraglia
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | | | | | - René Pavón-Madrid
- Campus San Pedro y San Pablo, Universidad Católica de Honduras, San Pedro Sula, Honduras
| | - Suyapa Aurora Bejarano
- Campus San Pedro y San Pablo, Universidad Católica de Honduras, San Pedro Sula, Honduras
- Liga Contra el Cancer, San Pedro Sula, Honduras
| | - Annabelle Ferrera
- Universidad Nacional Autónoma de Honduras, Escuela de Microbiologia, Edificio E1, 2da planta, Ciudad Universitaria Tegucigalpa, Tegucigalpa M.D.C., Honduras
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Miguel A. Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, México
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16
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Carreón-Rodríguez OE, Gutiérrez-Ríos RM, Acosta JL, Martinez A, Cevallos MA. Phenotypic and genomic analysis of Zymomonas mobilis ZM4 mutants with enhanced ethanol tolerance. ACTA ACUST UNITED AC 2019; 23:e00328. [PMID: 30984572 PMCID: PMC6444122 DOI: 10.1016/j.btre.2019.e00328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/10/2019] [Accepted: 03/18/2019] [Indexed: 12/22/2022]
Abstract
Z. mobilis ER79ag and ER79ap ethanol mutants were obtained by adaptive evolution. ER79ap had a better cell viability than the WT and ER79ap under ethanol stress. Mutants shared SNVs in clpP and spoT/relA, in addition ER79ap has a SNP in clpB. Mutant allele spoT/relA of ER79ap seems to be more important to ethanol tolerance. Glucose consumption and ethanol production were not affected in mutant strains.
Zymomonas mobilis ZM4 is an ethanol-producing microbe that is constitutively tolerant to this solvent. For a better understanding of the ethanol tolerance phenomenon we obtained and characterized two ZM4 mutants (ER79ap and ER79ag) with higher ethanol tolerance than the wild-type. Mutants were evaluated in different ethanol concentrations and this analysis showed that mutant ER79ap was more tolerant and had a better performance in terms of cell viability, than the wild-type strain and ER79ag mutant. Genotyping of the mutant strains showed that both carry non-synonymous mutations in clpP and spoT/relA genes. A third non-synonymous mutation was found only in strain ER79ap, in the clpB gene. Considering that ER79ap has the best tolerance to added ethanol, the mutant alleles of this strain were evaluated in ZM4 and here we show that while all of them contribute to ethanol tolerance, mutation within spoT/relA gene seems to be the most important.
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Affiliation(s)
- Ofelia E Carreón-Rodríguez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Rosa María Gutiérrez-Ríos
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - José L Acosta
- Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional (CIIDIR)-Unidad, Blvd., Juan de Dios Bátiz Paredes #250, 81101, Sinaloa, Mexico
| | - Alfredo Martinez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
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17
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Mancilla-Rojano J, Castro-Jaimes S, Ochoa SA, Bobadilla Del Valle M, Luna-Pineda VM, Bustos P, Laris-González A, Arellano-Galindo J, Parra-Ortega I, Hernández-Castro R, Cevallos MA, Xicohtencatl-Cortes J, Cruz-Córdova A. Whole-Genome Sequences of Five Acinetobacter baumannii Strains From a Child With Leukemia M2. Front Microbiol 2019; 10:132. [PMID: 30787915 PMCID: PMC6372515 DOI: 10.3389/fmicb.2019.00132] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 01/21/2019] [Indexed: 01/05/2023] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen and is one of the primary etiological agents of healthcare-associated infections (HAIs). A. baumannii infections are difficult to treat due to the intrinsic and acquired antibiotic resistance of strains of this bacterium, which frequently limits therapeutic options. In this study, five A. baumannii strains (810CP, 433H, 434H, 483H, and A-2), all of which were isolated from a child with leukemia M2, were characterized through antibiotic susceptibility profiling, the detection of genes encoding carbapenem hydrolyzing oxacillinases, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), adherence and invasion assays toward the A549 cell line, and the whole-genome sequence (WGS). The five strains showed Multidrug resistant (MDR) profiles and amplification of the blaOXA-23 gene, belonging to ST758 and grouped into two PFGE clusters. WGS of 810CP revealed the presence of a circular chromosome and two small plasmids, pAba810CPa and pAba810CPb. Both plasmids carried genes encoding the Sp1TA system, although resistance genes were not identified. A gene-by-gene comparison analysis was performed among the A. baumannii strains isolated in this study and others A. baumannii ST758 strains (HIMFG and INCan), showing that 86% of genes were present in all analyzed strains. Interestingly, the 433H, 434H, and 483H strains varied by 8–10 single-nucleotide variants (SNVs), while the A2 and 810CP strains varied by 46 SNVs. Subsequently, an analysis using BacWGSTdb showed that all of our strains had the same resistance genes and were ST758. However, some variations were observed in relation to virulence genes, mainly in the 810CP strain. The genes involved in the synthesis of hepta-acylated lipooligosaccharides, the pgaABCD locus encoding poly-β-1-6-N-acetylglucosamine, the ompA gene, Csu pili, bap, the two-component system bfms/bfmR, a member of the phospholipase D family, and two iron-uptake systems were identified in our A. baumannii strains genome. The five A. baumannii strains isolated from the child were genetically different and showed important characteristics that promote survival in a hospital environment. The elucidation of their genomic sequences provides important information for understanding their epidemiology, antibiotic resistance, and putative virulence factors.
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Affiliation(s)
- Jetsi Mancilla-Rojano
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.,Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Semiramis Castro-Jaimes
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Sara A Ochoa
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Miriam Bobadilla Del Valle
- Departamento de Enfermedades Infecciosas Instituto Nacional de Ciencias Médicas y de Nutrición "Salvador Zubirán", Mexico City, Mexico
| | - Victor M Luna-Pineda
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Patricia Bustos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Almudena Laris-González
- Departamento de Epidemiología, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - José Arellano-Galindo
- Laboratorio de Infectología, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Israel Parra-Ortega
- Laboratorio Central, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Rigoberto Hernández-Castro
- Departamento de Ecología de Agentes Patógenos Hospital General "Dr. Manuel Gea González", Mexico City, Mexico
| | - Miguel A Cevallos
- Centro de Ciencias Genómicas, Programa de Genómica Evolutiva, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Juan Xicohtencatl-Cortes
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Ariadnna Cruz-Córdova
- Laboratorio de Investigación en Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
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Romero-Gutierrez T, Peguero-Sanchez E, Cevallos MA, Batista CVF, Ortiz E, Possani LD. A Deeper Examination of Thorellius atrox Scorpion Venom Components with Omic Techonologies. Toxins (Basel) 2017; 9:E399. [PMID: 29231872 PMCID: PMC5744119 DOI: 10.3390/toxins9120399] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 02/02/2023] Open
Abstract
This communication reports a further examination of venom gland transcripts and venom composition of the Mexican scorpion Thorellius atrox using RNA-seq and tandem mass spectrometry. The RNA-seq, which was performed with the Illumina protocol, yielded more than 20,000 assembled transcripts. Following a database search and annotation strategy, 160 transcripts were identified, potentially coding for venom components. A novel sequence was identified that potentially codes for a peptide with similarity to spider ω-agatoxins, which act on voltage-gated calcium channels, not known before to exist in scorpion venoms. Analogous transcripts were found in other scorpion species. They could represent members of a new scorpion toxin family, here named omegascorpins. The mass fingerprint by LC-MS identified 135 individual venom components, five of which matched with the theoretical masses of putative peptides translated from the transcriptome. The LC-MS/MS de novo sequencing allowed to reconstruct and identify 42 proteins encoded by assembled transcripts, thus validating the transcriptome analysis. Earlier studies conducted with this scorpion venom permitted the identification of only twenty putative venom components. The present work performed with more powerful and modern omic technologies demonstrates the capacity of accomplishing a deeper characterization of scorpion venom components and the identification of novel molecules with potential applications in biomedicine and the study of ion channel physiology.
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Affiliation(s)
- Teresa Romero-Gutierrez
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
| | - Esteban Peguero-Sanchez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
| | - Cesar V F Batista
- Laboratorio Universitario de Proteómica, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
| | - Ernesto Ortiz
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
| | - Lourival D Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Apartado Postal 510-3, Cuernavaca CP: 62210, Morelos, Mexico.
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Graña-Miraglia L, Lozano LF, Velázquez C, Volkow-Fernández P, Pérez-Oseguera Á, Cevallos MA, Castillo-Ramírez S. Rapid Gene Turnover as a Significant Source of Genetic Variation in a Recently Seeded Population of a Healthcare-Associated Pathogen. Front Microbiol 2017; 8:1817. [PMID: 28979253 PMCID: PMC5611417 DOI: 10.3389/fmicb.2017.01817] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/06/2017] [Indexed: 12/11/2022] Open
Abstract
Genome sequencing has been useful to gain an understanding of bacterial evolution. It has been used for studying the phylogeography and/or the impact of mutation and recombination on bacterial populations. However, it has rarely been used to study gene turnover at microevolutionary scales. Here, we sequenced Mexican strains of the human pathogen Acinetobacter baumannii sampled from the same locale over a 3 year period to obtain insights into the microevolutionary dynamics of gene content variability. We found that the Mexican A. baumannii population was recently founded and has been emerging due to a rapid clonal expansion. Furthermore, we noticed that on average the Mexican strains differed from each other by over 300 genes and, notably, this gene content variation has accrued more frequently and faster than the accumulation of mutations. Moreover, due to its rapid pace, gene content variation reflects the phylogeny only at very short periods of time. Additionally, we found that the external branches of the phylogeny had almost 100 more genes than the internal branches. All in all, these results show that rapid gene turnover has been of paramount importance in producing genetic variation within this population and demonstrate the utility of genome sequencing to study alternative forms of genetic variation.
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Affiliation(s)
- Lucía Graña-Miraglia
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Luis F Lozano
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Consuelo Velázquez
- Departamento de Enfermedades Infecciosas, Instituto Nacional de CancerologíaMexico, Mexico
| | | | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de MéxicoCuernavaca, Mexico
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López-Leal G, Cevallos MA, Castillo-Ramírez S. Evolution of a Sigma Factor: An All-In-One of Gene Duplication, Horizontal Gene Transfer, Purifying Selection, and Promoter Differentiation. Front Microbiol 2016; 7:581. [PMID: 27199915 PMCID: PMC4843759 DOI: 10.3389/fmicb.2016.00581] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/08/2016] [Indexed: 01/11/2023] Open
Abstract
Sigma factors are an essential part of bacterial gene regulation and have been extensively studied as far as their molecular mechanisms and protein structure are concerned. However, their molecular evolution, especially for the alternative sigma factors, is poorly understood. Here, we analyze the evolutionary forces that have shaped the rpoH sigma factors within the alphaproteobacteria. We found that an ancient duplication gave rise to two major groups of rpoH sigma factors and that after this event horizontal gene transfer (HGT) occurred in rpoH1 group. We also noted that purifying selection has differentially affected distinct parts of the gene; singularly, the gene segment that encodes the region 4.2, which interacts with the −35 motif of the RpoH-dependent genes, has been under relaxed purifying selection. Furthermore, these two major groups are clearly differentiated from one another regarding their promoter selectivity, as rpoH1 is under the transcriptional control of σ70 and σ32, whereas rpoH2 is under the transcriptional control of σ24. Our results suggest a scenario in which HGT, gene loss, variable purifying selection and clear promoter specialization occurred after the ancestral duplication event. More generally, our study offers insights into the molecular evolution of alternative sigma factors and highlights the importance of analyzing not only the coding regions but also the promoter regions.
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Affiliation(s)
- Gamaliel López-Leal
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México Mexico City, Mexico
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de México Cuernavaca, Mexico
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Génomicas, Universidad Nacional Autónoma de México Cuernavaca, Mexico
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Rivera-Urbalejo A, Pérez-Oseguera Á, Carreón-Rodríguez OE, Cevallos MA. Mutations in an antisense RNA, involved in the replication control of a repABC plasmid, that disrupt plasmid incompatibility and mediate plasmid speciation. Plasmid 2015; 78:48-58. [PMID: 25644116 DOI: 10.1016/j.plasmid.2015.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 01/19/2015] [Accepted: 01/22/2015] [Indexed: 11/18/2022]
Abstract
The maintenance of large plasmid in a wide variety of alpha-proteobacteria depends on the repABC replication/segregation unit. The intergenic repB-repC region of these plasmids encodes a countertranscribed RNA (ctRNA) that modulates the transcription/translation rate of RepC, the initiator protein. The ctRNA acts as a strong incompatibility factor when expressed in trans. We followed a site directed mutagenesis approach to map those sequences of the ctRNA that are required for plasmid incompatibility and for plasmid replication control. We found that the first three nucleotides of the 5'-end of the ctRNA are essential for interactions with its target RNA. We also found that stretches of 4-5 nucleotides of non-complementarity within the first 10 nucleotides of the left arm of the ctRNA and the target RNA are sufficient to avoid plasmid incompatibility. Additionally, miniplasmid derivatives expressing ctRNAs with mutations in the 5' end or small deletions in the ctRNA are capable of controlling their own replication and coexisting with the parental plasmid. We suggest that a mechanism that could have a crucial role in the speciation process of repABC plasmids is to accumulate enough changes in this small region of the ctRNA gene to disrupt heteroduplex formation between the target RNA of one plasmid and the ctRNA of the other. Plasmids carrying these changes will not have defects in their maintenance.
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Affiliation(s)
- América Rivera-Urbalejo
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México
| | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México
| | - Ofelia E Carreón-Rodríguez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México.
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Wiesner M, Fernández-Mora M, Cevallos MA, Zavala-Alvarado C, Zaidi MB, Calva E, Silva C. Conjugative transfer of an IncA/C plasmid-borne blaCMY-2 gene through genetic re-arrangements with an IncX1 plasmid. BMC Microbiol 2013; 13:264. [PMID: 24262067 PMCID: PMC4222815 DOI: 10.1186/1471-2180-13-264] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 11/15/2013] [Indexed: 11/13/2022] Open
Abstract
Background Our observation that in the Mexican Salmonella Typhimurium population none of the ST19 and ST213 strains harbored both the Salmonella virulence plasmid (pSTV) and the prevalent IncA/C plasmid (pA/C) led us to hypothesize that restriction to horizontal transfer of these plasmids existed. We designed a conjugation scheme using ST213 strain YU39 as donor of the blaCMY-2 gene (conferring resistance to ceftriaxone; CRO) carried by pA/C, and two E. coli lab strains (DH5α and HB101) and two Typhimurium ST19 strains (SO1 and LT2) carrying pSTV as recipients. The aim of this study was to determine if the genetic background of the different recipient strains affected the transfer frequencies of pA/C. Results YU39 was able to transfer CRO resistance, via a novel conjugative mechanism, to all the recipient strains although at low frequencies (10-7 to 10-10). The presence of pSTV in the recipients had little effect on the conjugation frequency. The analysis of the transconjugants showed that three different phenomena were occurring associated to the transfer of blaCMY-2: 1) the co-integration of pA/C and pX1; 2) the transposition of the CMY region from pA/C to pX1; or 3) the rearrangement of pA/C. In addition, the co-lateral mobilization of a small (5 kb) ColE1-like plasmid was observed. The transconjugant plasmids involving pX1 re-arrangements (either via co-integration or ISEcp1-mediated transposition) obtained the capacity to conjugate at very high levels, similar to those found for pX1 (10-1). Two versions of the region containing blaCMY-2 were found to transpose to pX1: the large version was inserted into an intergenic region located where the “genetic load” operons are frequently inserted into pX1, while the short version was inserted into the stbDE operon involved in plasmid addiction system. This is the first study to report the acquisition of an extended spectrum cephalosporin (ESC)-resistance gene by an IncX1 plasmid. Conclusions We showed that the transfer of the YU39 blaCMY-2 gene harbored on a non- conjugative pA/C requires the machinery of a highly conjugative pX1 plasmid. Our experiments demonstrate the complex interactions a single strain can exploit to contend with the challenge of horizontal transfer and antibiotic selective pressure.
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Affiliation(s)
- Magdalena Wiesner
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, Cuernavaca, Morelos, México.
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Orduña P, Cevallos MA, de León SP, Arvizu A, Hernández-González IL, Mendoza-Hernández G, López-Vidal Y. Genomic and proteomic analyses of Mycobacterium bovis BCG Mexico 1931 reveal a diverse immunogenic repertoire against tuberculosis infection. BMC Genomics 2011; 12:493. [PMID: 21981907 PMCID: PMC3199284 DOI: 10.1186/1471-2164-12-493] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 10/08/2011] [Indexed: 12/03/2022] Open
Abstract
Background Studies of Mycobacterium bovis BCG strains used in different countries and vaccination programs show clear variations in the genomes and immune protective properties of BCG strains. The aim of this study was to characterise the genomic and immune proteomic profile of the BCG 1931 strain used in Mexico. Results BCG Mexico 1931 has a circular chromosome of 4,350,386 bp with a G+C content and numbers of genes and pseudogenes similar to those of BCG Tokyo and BCG Pasteur. BCG Mexico 1931 lacks Region of Difference 1 (RD1), RD2 and N-RD18 and one copy of IS6110, indicating that BCG Mexico 1931 belongs to DU2 group IV within the BCG vaccine genealogy. In addition, this strain contains three new RDs, which are 53 (RDMex01), 655 (RDMex02) and 2,847 bp (REDMex03) long, and 55 single-nucleotide polymorphisms representing non-synonymous mutations compared to BCG Pasteur and BCG Tokyo. In a comparative proteomic analysis, the BCG Mexico 1931, Danish, Phipps and Tokyo strains showed 812, 794, 791 and 701 protein spots, respectively. The same analysis showed that BCG Mexico 1931 shares 62% of its protein spots with the BCG Danish strain, 61% with the BCG Phipps strain and only 48% with the BCG Tokyo strain. Thirty-nine reactive spots were detected in BCG Mexico 1931 using sera from subjects with active tuberculosis infections and positive tuberculin skin tests. Conclusions BCG Mexico 1931 has a smaller genome than the BCG Pasteur and BCG Tokyo strains. Two specific deletions in BCG Mexico 1931 are described (RDMex02 and RDMex03). The loss of RDMex02 (fadD23) is associated with enhanced macrophage binding and RDMex03 contains genes that may be involved in regulatory pathways. We also describe new antigenic proteins for the first time.
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Affiliation(s)
- Patricia Orduña
- Programa de Inmunología Molecular Microbiana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, DF, México
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Cervantes-Rivera R, Pedraza-López F, Pérez-Segura G, Cevallos MA. The replication origin of a repABC plasmid. BMC Microbiol 2011; 11:158. [PMID: 21718544 PMCID: PMC3155836 DOI: 10.1186/1471-2180-11-158] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 06/30/2011] [Indexed: 11/21/2022] Open
Abstract
Background repABC operons are present on large, low copy-number plasmids and on some secondary chromosomes in at least 19 α-proteobacterial genera, and are responsible for the replication and segregation properties of these replicons. These operons consist, with some variations, of three genes: repA, repB, and repC. RepA and RepB are involved in plasmid partitioning and in the negative regulation of their own transcription, and RepC is the limiting factor for replication. An antisense RNA encoded between the repB-repC genes modulates repC expression. Results To identify the minimal region of the Rhizobium etli p42d plasmid that is capable of autonomous replication, we amplified different regions of the repABC operon using PCR and cloned the regions into a suicide vector. The resulting vectors were then introduced into R. etli strains that did or did not contain p42d. The minimal replicon consisted of a repC open reading frame under the control of a constitutive promoter with a Shine-Dalgarno sequence that we designed. A sequence analysis of repC revealed the presence of a large A+T-rich region but no iterons or DnaA boxes. Silent mutations that modified the A+T content of this region eliminated the replication capability of the plasmid. The minimal replicon could not be introduced into R. etli strain containing p42d, but similar constructs that carried repC from Sinorhizobium meliloti pSymA or the linear chromosome of Agrobacterium tumefaciens replicated in the presence or absence of p42d, indicating that RepC is an incompatibility factor. A hybrid gene construct expressing a RepC protein with the first 362 amino acid residues from p42d RepC and the last 39 amino acid residues of RepC from SymA was able to replicate in the presence of p42d. Conclusions RepC is the only element encoded in the repABC operon of the R. etli p42d plasmid that is necessary and sufficient for plasmid replication and is probably the initiator protein. The oriV of this plasmid resides within the repC gene and is located close to or inside of a large A+T region. RepC can act as an incompatibility factor, and the last 39 amino acid residues of the carboxy-terminal region of this protein are involved in promoting this phenotype.
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Affiliation(s)
- Ramón Cervantes-Rivera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México
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Wiesner M, Calva E, Fernández-Mora M, Cevallos MA, Campos F, Zaidi MB, Silva C. Salmonella Typhimurium ST213 is associated with two types of IncA/C plasmids carrying multiple resistance determinants. BMC Microbiol 2011; 11:9. [PMID: 21223599 PMCID: PMC3025833 DOI: 10.1186/1471-2180-11-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 01/11/2011] [Indexed: 12/03/2022] Open
Abstract
Background Salmonella Typhimurium ST213 was first detected in the Mexican Typhimurium population in 2001. It is associated with a multi-drug resistance phenotype and a plasmid-borne blaCMY-2 gene conferring resistance to extended-spectrum cephalosporins. The objective of the current study was to examine the association between the ST213 genotype and blaCMY-2 plasmids. Results The blaCMY-2 gene was carried by an IncA/C plasmid. ST213 strains lacking the blaCMY-2 gene carried a different IncA/C plasmid. PCR analysis of seven DNA regions distributed throughout the plasmids showed that these IncA/C plasmids were related, but the presence and absence of DNA stretches produced two divergent types I and II. A class 1 integron (dfrA12, orfF and aadA2) was detected in most of the type I plasmids. Type I contained all the plasmids carrying the blaCMY-2 gene and a subset of plasmids lacking blaCMY-2. Type II included all of the remaining blaCMY-2-negative plasmids. A sequence comparison of the seven DNA regions showed that both types were closely related to IncA/C plasmids found in Escherichia, Salmonella, Yersinia, Photobacterium, Vibrio and Aeromonas. Analysis of our Typhimurium strains showed that the region containing the blaCMY-2 gene is inserted between traA and traC as a single copy, like in the E. coli plasmid pAR060302. The floR allele was identical to that of Newport pSN254, suggesting a mosaic pattern of ancestry with plasmids from other Salmonella serovars and E. coli. Only one of the tested strains was able to conjugate the IncA/C plasmid at very low frequencies (10-7 to 10-9). The lack of conjugation ability of our IncA/C plasmids agrees with the clonal dissemination trend suggested by the chromosomal backgrounds and plasmid pattern associations. Conclusions The ecological success of the newly emerging Typhimurium ST213 genotype in Mexico may be related to the carriage of IncA/C plasmids. We conclude that types I and II of IncA/C plasmids originated from a common ancestor and that the insertion and deletion of DNA stretches have shaped their evolutionary histories.
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Affiliation(s)
- Magdalena Wiesner
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
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Quinto C, De La Vega H, Flores M, Leemans J, Cevallos MA, Pardo MA, Azpiroz R, De Lourdes Girard M, Calva E, Palacios R. Nitrogenase reductase: A functional multigene family in Rhizobium phaseoli. Proc Natl Acad Sci U S A 2010; 82:1170-4. [PMID: 16593543 PMCID: PMC397216 DOI: 10.1073/pnas.82.4.1170] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The complete coding sequence of the nitrogenase reductase gene (nifH) is present in three different regions of a Rhizobium phaseoli symbiotic plasmid. Homology between two of the regions containing nifH coding sequences extends over 5 kilobases. These in turn share 1.3 kilobases of homology with the third region. The nucleotide sequences of the three nitrogenase reductase genes were found to be identical. Site-directed insertion mutagenesis indicated that none of the three genes is indispensable for nitrogen fixation during symbiosis with Phaseolus vulgaris. This implies that at least two of the reiterated genes can be functionally expressed.
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Affiliation(s)
- C Quinto
- Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado postal 565-A, Cuernavaca, Morelos, Mexico
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Castillo-Ramírez S, Vázquez-Castellanos JF, González V, Cevallos MA. Horizontal gene transfer and diverse functional constrains within a common replication-partitioning system in Alphaproteobacteria: the repABC operon. BMC Genomics 2009; 10:536. [PMID: 19919719 PMCID: PMC2783167 DOI: 10.1186/1471-2164-10-536] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2009] [Accepted: 11/18/2009] [Indexed: 11/24/2022] Open
Abstract
Background The repABC plasmid family, which is extensively present within Alphaproteobacteria, and some secondary chromosomes of the Rhizobiales have the particular feature that all the elements involved in replication and partitioning reside within one transcriptional unit, the repABC operon. Given the functional interactions among the elements of the repABC operon, and the fact that they all reside in the same operon, a common evolutionary history would be expected if the entire operon had been horizontally transferred. Here, we tested whether there is a common evolutionary history within the repABC operon. We further examined different incompatibility groups in terms of their differentiation and degree of adaptation to their host. Results We did not find a single evolutionary history within the repABC operon. Each protein had a particular phylogeny, horizontal gene transfer events of the individual genes within the operon were detected, and different functional constraints were found within and between the Rep proteins. When different repABC operons coexisted in the same genome, they were well differentiated from one another. Finally, we found different levels of adaptation to the host genome within and between repABC operons coexisting in the same species. Conclusion Horizontal gene transfer with conservation of the repABC operon structure provides a highly dynamic operon in which each member of this operon has its own evolutionary dynamics. In addition, it seems that different incompatibility groups present in the same species have different degrees of adaptation to their host genomes, in proportion to the amount of time the incompatibility group has coexisted with the host genome.
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Affiliation(s)
- Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
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Suárez R, Wong A, Ramírez M, Barraza A, Orozco MDC, Cevallos MA, Lara M, Hernández G, Iturriaga G. Improvement of drought tolerance and grain yield in common bean by overexpressing trehalose-6-phosphate synthase in rhizobia. Mol Plant Microbe Interact 2008; 21:958-66. [PMID: 18533836 DOI: 10.1094/mpmi-21-7-0958] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Improving stress tolerance and yield in crops are major goals for agriculture. Here, we show a new strategy to increase drought tolerance and yield in legumes by overexpressing trehalose-6-phosphate synthase in the symbiotic bacterium Rhizobium etli. Phaseolus vulgaris (common beans) plants inoculated with R. etli overexpressing trehalose-6-phosphate synthase gene had more nodules with increased nitrogenase activity and higher biomass compared with plants inoculated with wild-type R. etli. In contrast, plants inoculated with an R. etli mutant in trehalose-6-phosphate synthase gene had fewer nodules and less nitrogenase activity and biomass. Three-week-old plants subjected to drought stress fully recovered whereas plants inoculated with a wild-type or mutant strain wilted and died. The yield of bean plants inoculated with R. etli overexpressing trehalose-6-phosphate synthase gene and grown with constant irrigation increased more than 50%. Macroarray analysis of 7,200 expressed sequence tags from nodules of plants inoculated with the strain overexpressing trehalose-6-phosphate synthase gene revealed upregulation of genes involved in stress tolerance and carbon and nitrogen metabolism, suggesting a signaling mechanism for trehalose. Thus, trehalose metabolism in rhizobia is key for signaling plant growth, yield, and adaptation to abiotic stress, and its manipulation has a major agronomical impact on leguminous plants.
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Affiliation(s)
- Ramón Suárez
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca Mor. 62209, Mexico
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Guo X, Castillo-Ramírez S, González V, Bustos P, Luís Fernández-Vázquez J, Santamaría RI, Arellano J, Cevallos MA, Dávila G. Rapid evolutionary change of common bean (Phaseolus vulgaris L) plastome, and the genomic diversification of legume chloroplasts. BMC Genomics 2007; 8:228. [PMID: 17623083 PMCID: PMC1940014 DOI: 10.1186/1471-2164-8-228] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 07/10/2007] [Indexed: 12/05/2022] Open
Abstract
Background Fabaceae (legumes) is one of the largest families of flowering plants, and some members are important crops. In contrast to what we know about their great diversity or economic importance, our knowledge at the genomic level of chloroplast genomes (cpDNAs or plastomes) for these crops is limited. Results We sequenced the complete genome of the common bean (Phaseolus vulgaris cv. Negro Jamapa) chloroplast. The plastome of P. vulgaris is a 150,285 bp circular molecule. It has gene content similar to that of other legume plastomes, but contains two pseudogenes, rpl33 and rps16. A distinct inversion occurred at the junction points of trnH-GUG/rpl14 and rps19/rps8, as in adzuki bean [1]. These two pseudogenes and the inversion were confirmed in 10 varieties representing the two domestication centers of the bean. Genomic comparative analysis indicated that inversions generally occur in legume plastomes and the magnitude and localization of insertions/deletions (indels) also vary. The analysis of repeat sequences demonstrated that patterns and sequences of tandem repeats had an important impact on sequence diversification between legume plastomes and tandem repeats did not belong to dispersed repeats. Interestingly, P. vulgaris plastome had higher evolutionary rates of change on both genomic and gene levels than G. max, which could be the consequence of pressure from both mutation and natural selection. Conclusion Legume chloroplast genomes are widely diversified in gene content, gene order, indel structure, abundance and localization of repetitive sequences, intracellular sequence exchange and evolutionary rates. The P. vulgaris plastome is a rapidly evolving genome.
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Affiliation(s)
- Xianwu Guo
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Santiago Castillo-Ramírez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Víctor González
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Patricia Bustos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - José Luís Fernández-Vázquez
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Rosa Isela Santamaría
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Jesús Arellano
- Programa de Genómica Funcional de Eucariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Miguel A Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
| | - Guillermo Dávila
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, México
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Abstract
A collection of Rhizobium etli promoters was isolated from a genomic DNA library constructed in the promoter-trap vector pBBMCS53, by their ability to drive the expression of a gusA reporter gene. Thirty-seven clones were selected, and their transcriptional start-sites were determined. The upstream sequence of these 37 start-sites, and the sequences of seven previously identified promoters were compared. On the basis of sequence conservation and mutational analysis, a consensus sequence CTTGACN16–23TATNNT was obtained. In this consensus sequence, nine on of twelve bases are identical to the canonical Escherichia coli σ70 promoter, however the R.etli promoters only contain 6.4 conserved bases on average. We show that the R.etli sigma factor SigA recognizes all R.etli promoters studied in this work, and that E.coli RpoD is incapable of recognizing them. The comparison of the predicted structure of SigA with the known structure of RpoD indicated that regions 2.4 and 4.2, responsible for promoter recognition, are different only by a single amino acid, whereas the region 1 of SigA contains 72 extra residues, suggesting that the differences contained in this region could be related to the lax promoter recognition of SigA.
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Aguilar-Díaz H, Bobes RJ, Carrero JC, Camacho-Carranza R, Cervantes C, Cevallos MA, Dávila G, Rodríguez-Dorantes M, Escobedo G, Fernández JL, Fragoso G, Gaytán P, Garciarubio A, González VM, González L, José MV, Jiménez L, Laclette JP, Landa A, Larralde C, Morales-Montor J, Morett E, Ostoa-Saloma P, Sciutto E, Santamaría RI, Soberón X, de la Torre P, Valdés V, Yánez J. The genome project of Taenia solium. Parasitol Int 2005; 55 Suppl:S127-30. [PMID: 16337432 DOI: 10.1016/j.parint.2005.11.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have constituted a consortium of key laboratories at the National Autonomous University of Mexico to carry out a genomic project for Taenia solium. This project will provide powerful resources for the study of taeniasis/cysticercosis, and, in conjunction with the Echinococcus granulosus and Echinococcus multilocularis genome project of expressed sequence tags (ESTs), will mark the advent of genomics for cestode parasites. Our project is planned in two consecutive stages. The first stage is being carried out to determine some basic parameters of the T. solium genome. Afterwards, we will evaluate the best strategy for the second stage, a full blown genome project. We have estimated the T. solium genome size by two different approaches: cytofluorometry on isolated cyton nuclei, as well as a probabilistic calculation based on approximately 2000 sequenced genomic clones, approximately 3000 ESTs, resulting in size estimates of 270 and 251 Mb, respectively. In terms of sequencing, our goal for the first stage is to characterize several thousand EST's (from adult worm and cysticerci cDNA libraries) and genomic clones. Results obtained so far from about 16,000 sequenced ESTs from the adult stage, show that only about 40% of the T. solium coding sequences have a previously sequenced homologue. Many of the best hits are found with mammalian genes, especially with humans. However, 1.5% of the hits lack homologues in humans, making these genes immediate candidates for investigation on pharmaco-therapy, diagnostics and vaccination. Most T. solium ESTs are related to gene regulation, and signal transduction. Other important functions are housekeeping, metabolism, cell division, cytoskeleton, proteases, vacuolar transport, hormone response, and extracellular matrix activities. Preliminary results also suggest that the genome of T. solium is not highly repetitive.
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Affiliation(s)
- Hugo Aguilar-Díaz
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico
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Izquierdo J, Venkova-Canova T, Ramírez-Romero MA, Téllez-Sosa J, Hernández-Lucas I, Sanjuan J, Cevallos MA. An antisense RNA plays a central role in the replication control of a repC plasmid. Plasmid 2005; 54:259-77. [PMID: 16005966 DOI: 10.1016/j.plasmid.2005.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2005] [Revised: 05/17/2005] [Accepted: 05/17/2005] [Indexed: 11/23/2022]
Abstract
The widespread replicons of repABC and repC families from alpha-proteobacteria share high similarity in their replication initiator proteins (RepC). Here we describe the minimal region required for stable replication of a member of the repC family, the low copy-number plasmid pRmeGR4a from Sinorizobium meliloti GR4. This region contains only two genes: one encoding the initiator protein RepC (46.8 kDa) and other, an antisense RNA (67 nt). Mapping of transcriptional start sites and promoter regions of both genes showed that the antisense RNA is nested within the repC mRNA leader. The constitutively expressed countertranscribed RNA (ctRNA) forms a single stem-loop structure that acts as an intrinsic rho-independent terminator. The ctRNA is a strong trans-incompatibility factor and negative regulator of repC expression. Based on structural and functional similarities between members of the repC and repABC families we propose a model of their evolutionary relationship.
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MESH Headings
- Amino Acid Sequence
- Conjugation, Genetic
- DNA Replication
- DNA, Bacterial
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Glucuronidase/analysis
- Glucuronidase/metabolism
- Molecular Sequence Data
- Molecular Weight
- Mutagenesis, Site-Directed
- Phylogeny
- Plasmids/chemistry
- Plasmids/genetics
- Plasmids/metabolism
- Promoter Regions, Genetic
- RNA, Antisense/genetics
- RNA, Antisense/physiology
- RNA, Bacterial/genetics
- RNA, Bacterial/physiology
- RNA, Messenger/genetics
- Replicon
- Rhizobium etli/genetics
- Sequence Homology, Amino Acid
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Affiliation(s)
- Javier Izquierdo
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
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Dávila S, Piñero D, Bustos P, Cevallos MA, Dávila G. The mitochondrial genome sequence of the scorpion Centruroides limpidus (Karsch 1879) (Chelicerata; Arachnida). Gene 2005; 360:92-102. [PMID: 16183216 DOI: 10.1016/j.gene.2005.06.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Revised: 04/15/2005] [Accepted: 06/02/2005] [Indexed: 11/23/2022]
Abstract
The mitochondrial genome of the scorpion Centruroides limpidus (Chelicerata; Arachnida) has been completely sequenced and is 14519 bp long. The genome contains 13 protein-encoding genes, two ribosomal RNA genes, 21 transfer RNA genes and a large non-coding region related to the control region. The overall A+T composition is the lowest among the complete mitochondrial sequences published within the Chelicerata subphylum. Gene order and gene content differ slightly from that of Limulus polyphemus (Chelicerata: Xiphosura): i.e., the lack of the trnD gene, and the translocation-inversion of the trnI gene. Preliminary phylogenetic analysis of some Chelicerata shows that scorpions (C. limpidus and Mesobuthus gibbosus) make a tight cluster with the spiders (Arachnida; Araneae). Our analysis does not support that Scorpiones order is the sister group to all Arachnida Class, since it is closer to Araneae than to Acari orders.
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Affiliation(s)
- Sonia Dávila
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas - UNAM, Avenida Universidad, s/n, Chamilpa, Cuernavaca 62210, Apartado Postal 565-A, Morelos, Mexico
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Venkova-Canova T, Soberón NE, Ramírez-Romero MA, Cevallos MA. Two discrete elements are required for the replication of a repABC plasmid: an antisense RNA and a stem-loop structure. Mol Microbiol 2005; 54:1431-44. [PMID: 15554980 DOI: 10.1111/j.1365-2958.2004.04366.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The repABC replicons contain an operon encoding the initiator protein (RepC) and partitioning proteins (RepA and RepB). The latter two proteins negatively regulate the transcription of the operon. In this article we have identified two novel regulatory elements, located within the conserved repB-repC intergenic sequence, which negatively modulate the expression of repC, in plasmid p42d of Rhizobium etli. One of them is a small antisense RNA and the other is a stem-loop structure in the repABC mRNA that occludes the Shine-Dalgarno sequence of repC. According to in vivo and in vitro analyses, the small antisense RNA (57-59 nt) resembles canonical negative regulators of replication because: (i) it is transcribed from a strong constitutive promoter (P2), (ii) the transcript overlaps untranslated region upstream of the RepC coding sequences, (iii) the RNA forms one secondary structure acting as a rho-independent terminator, (iv) the antisense RNA is a strong trans-incompatibility factor and (v) its presence reduces the level of repC expression. Surprisingly, both of these seemingly negative regulators are required for efficient plasmid replication.
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MESH Headings
- Base Sequence
- DNA Replication
- DNA, Bacterial/genetics
- DNA, Bacterial/metabolism
- DNA, Intergenic/genetics
- DNA, Intergenic/physiology
- Gene Expression Regulation, Bacterial
- Models, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- Operon
- Plasmids/genetics
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Biosynthesis
- RNA, Antisense/genetics
- RNA, Antisense/physiology
- RNA, Bacterial/genetics
- RNA, Bacterial/physiology
- RNA, Messenger/genetics
- RNA, Messenger/physiology
- Rhizobium etli/genetics
- Sequence Alignment
- Untranslated Regions
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Affiliation(s)
- Tatiana Venkova-Canova
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, C.P 62210, Cuernavaca, Morelos, Mexico
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Soberón N, Venkova-Canova T, Ramírez-Romero MA, Téllez-Sosa J, Cevallos MA. Incompatibility and the partitioning site of the repABC basic replicon of the symbiotic plasmid from Rhizobium etli. Plasmid 2004; 51:203-16. [PMID: 15109827 DOI: 10.1016/j.plasmid.2004.01.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 01/20/2004] [Indexed: 11/19/2022]
Abstract
The basic replicon of the symbiotic plasmid (p42d) of Rhizobium etli CE3 is constituted by the repABC operon. Whereas RepC is essential for plasmid replication, RepA and RepB are involved in plasmid partitioning. Three incompatibility regions have been previously identified in this plasmid: the first one encodes RepA, a partitioning protein that also down-regulates the repABC transcription. The second region is situated within the repB-repC intergenic sequence (inc(alpha)), and the last one, inc(beta), is located in a 502 bp EcoRI fragment spanning the last 72-bp of the coding region of repC and the following downstream sequence. In this paper we show that: (1) The inc(beta) region is required for plasmid partitioning. (2) A 16-bp palindrome sequence, located 40 bp downstream of the repC gene of plasmid p42d, is necessary and sufficient to induce incompatibility towards the parental plasmid, and accounts for all the incompatibility properties of this region (inc(beta)). (3). The palindrome is the DNA target site for RepB binding. With these findings we propose that inc(beta) contains the partitioning site (par site) of the basic replicon of plasmid p42d, and that the 16-bp palindrome is the core sequence to nucleate the RepB binding.
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Affiliation(s)
- Nora Soberón
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos
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González V, Bustos P, Ramírez-Romero MA, Medrano-Soto A, Salgado H, Hernández-González I, Hernández-Celis JC, Quintero V, Moreno-Hagelsieb G, Girard L, Rodríguez O, Flores M, Cevallos MA, Collado-Vides J, Romero D, Dávila G. The mosaic structure of the symbiotic plasmid of Rhizobium etli CFN42 and its relation to other symbiotic genome compartments. Genome Biol 2003; 4:R36. [PMID: 12801410 PMCID: PMC193615 DOI: 10.1186/gb-2003-4-6-r36] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2002] [Revised: 03/06/2003] [Accepted: 04/02/2003] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Symbiotic bacteria known as rhizobia interact with the roots of legumes and induce the formation of nitrogen-fixing nodules. In rhizobia, essential genes for symbiosis are compartmentalized either in symbiotic plasmids or in chromosomal symbiotic islands. To understand the structure and evolution of the symbiotic genome compartments (SGCs), it is necessary to analyze their common genetic content and organization as well as to study their differences. To date, five SGCs belonging to distinct species of rhizobia have been entirely sequenced. We report the complete sequence of the symbiotic plasmid of Rhizobium etli CFN42, a microsymbiont of beans, and a comparison with other SGC sequences available. RESULTS The symbiotic plasmid is a circular molecule of 371,255 base-pairs containing 359 coding sequences. Nodulation and nitrogen-fixation genes common to other rhizobia are clustered in a region of 125 kilobases. Numerous sequences related to mobile elements are scattered throughout. In some cases the mobile elements flank blocks of functionally related sequences, thereby suggesting a role in transposition. The plasmid contains 12 reiterated DNA families that are likely to participate in genomic rearrangements. Comparisons between this plasmid and complete rhizobial genomes and symbiotic compartments already sequenced show a general lack of synteny and colinearity, with the exception of some transcriptional units. There are only 20 symbiotic genes that are shared by all SGCs. CONCLUSIONS Our data support the notion that the symbiotic compartments of rhizobia genomes are mosaic structures that have been frequently tailored by recombination, horizontal transfer and transposition.
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Affiliation(s)
- Víctor González
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Patricia Bustos
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Miguel A Ramírez-Romero
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Arturo Medrano-Soto
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Heladia Salgado
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Ismael Hernández-González
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Juan Carlos Hernández-Celis
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Verónica Quintero
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Gabriel Moreno-Hagelsieb
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Lourdes Girard
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Oscar Rodríguez
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Margarita Flores
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Miguel A Cevallos
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Julio Collado-Vides
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - David Romero
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
| | - Guillermo Dávila
- Centro de Investigación Sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México 62210
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Quintero V, Cevallos MA, Dávila G. A site-specific recombinase (RinQ) is required to exert incompatibility towards the symbiotic plasmid of Rhizobium etli. Mol Microbiol 2002; 46:1023-32. [PMID: 12421308 DOI: 10.1046/j.1365-2958.2002.03205.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The replication/partition region of the symbiotic plasmid p42d of Rhizobium etli CE3 is characterized by the presence of the repABC operon. A recombinant plasmid containing this region is able to replicate in a R. etli derivative cured from p42d, with the same stability and copy number shown by the parental plasmid. However, when this construct is introduced into the wild-type strain, instead of exerting incompatibility against the p42d, it forms a stable cointegrate with it. In this paper, we show that a site-specific resolvase, and its action sites are essential factors to displace the symbiotic p42d. We propose a model for this novel incompatibility mechanism.
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Affiliation(s)
- Verónica Quintero
- Programa de Evolución Molecular, centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Morelos, México
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38
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Cevallos MA, Porta H, Izquierdo J, Tun-Garrido C, García-de-los-Santos A, Dávila G, Brom S. Rhizobium etli CFN42 contains at least three plasmids of the repABC family: a structural and evolutionary analysis. Plasmid 2002; 48:104-16. [PMID: 12383728 DOI: 10.1016/s0147-619x(02)00119-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In this paper, we report the identification of replication/partition regions of plasmid p42a and p42b of Rhizobium etli CFN42. Sequence analysis reveals that both replication/partition regions belong to the repABC family. Phylogenetic analysis of all the complete repABC replication/partition regions reported to date, shows that repABC plasmids coexisting in the same strain arose most likely by lateral transfer instead of by duplication followed by divergence. A model explaining how new incompatibility groups originate, is proposed.
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Affiliation(s)
- Miguel A Cevallos
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico.
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39
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Téllez-Sosa J, Soberón N, Vega-Segura A, Torres-Márquez ME, Cevallos MA. The Rhizobium etli cyaC product: characterization of a novel adenylate cyclase class. J Bacteriol 2002; 184:3560-8. [PMID: 12057950 PMCID: PMC135151 DOI: 10.1128/jb.184.13.3560-3568.2002] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2001] [Accepted: 04/07/2002] [Indexed: 11/20/2022] Open
Abstract
Adenylate cyclases (ACs) catalyze the formation of 3',5'-cyclic AMP (cAMP) from ATP. A novel AC-encoding gene, cyaC, was isolated from Rhizobium etli by phenotypic complementation of an Escherichia coli cya mutant. The functionality of the cyaC gene was corroborated by its ability to restore cAMP accumulation in an E. coli cya mutant. Further, overexpression of a malE::cyaC fusion protein allowed the detection of significant AC activity levels in cell extracts of an E. coli cya mutant. CyaC is unrelated to any known AC or to any other protein exhibiting a currently known function. Thus, CyaC represents the first member of a novel class of ACs (class VI). Hypothetical genes of unknown function similar to cyaC have been identified in the genomes of the related bacterial species Mesorhizobium loti, Sinorhizobium meliloti, and Agrobacterium tumefaciens. The cyaC gene is cotranscribed with a gene similar to ohr of Xanthomonas campestris and is expressed only in the presence of organic hydroperoxides. The physiological performance of an R. etli cyaC mutant was indistinguishable from that of the wild-type parent strain both under free-living conditions and during symbiosis.
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Affiliation(s)
- Juan Téllez-Sosa
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, C.P. 62210, Cuernavaca, Morelos
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40
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Ramírez-Romero MA, Téllez-Sosa J, Barrios H, Pérez-Oseguera A, Rosas V, Cevallos MA. RepA negatively autoregulates the transcription of the repABC operon of the Rhizobium etli symbiotic plasmid basic replicon. Mol Microbiol 2001; 42:195-204. [PMID: 11679078 DOI: 10.1046/j.1365-2958.2001.02621.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The basic replicon of Rhizobium etli CE3, like other members of the repABC plasmid family, is constituted by the repABC operon. RepC is essential for replication, and RepA and RepB play a role in plasmid segregation. It has been shown that deletion derivatives lacking the repAB genes have an increased copy number, indicating that these genes participate in the control of plasmid copy number. RepA is also a trans-incompatibility factor. To understand the regulation of the repABC operon, in this paper: (i) the transcription start site of the repABC operon was determined; (ii) the promoter region was identified by site-directed mutagenesis of the putative -35 and -10 hexameric elements; and (iii) RepA was recognized as a negative regulator of the transcription of the repABC operon.
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Affiliation(s)
- M A Ramírez-Romero
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, México
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41
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Ramírez-Romero MA, Soberón N, Pérez-Oseguera A, Téllez-Sosa J, Cevallos MA. Structural elements required for replication and incompatibility of the Rhizobium etli symbiotic plasmid. J Bacteriol 2000; 182:3117-24. [PMID: 10809690 PMCID: PMC94497 DOI: 10.1128/jb.182.11.3117-3124.2000] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/1999] [Accepted: 02/25/2000] [Indexed: 11/20/2022] Open
Abstract
The symbiotic plasmid of Rhizobium etli CE3 belongs to the RepABC family of plasmid replicons. This family is characterized by the presence of three conserved genes, repA, repB, and repC, encoded by the same DNA strand. A long intergenic sequence (igs) between repB and repC is also conserved in all members of the plasmid family. In this paper we demonstrate that (i) the repABC genes are organized in an operon; (ii) the RepC product is essential for replication; (iii) RepA and RepB products participate in plasmid segregation and in the regulation of plasmid copy number; (iv) there are two cis-acting incompatibility regions, one located in the igs (incalpha) and the other downstream of repC (incbeta) (the former is essential for replication); and (v) RepA is a trans-acting incompatibility factor. We suggest that incalpha is a cis-acting site required for plasmid partitioning and that the origin of replication lies within incbeta.
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Affiliation(s)
- M A Ramírez-Romero
- Programa de Evolución Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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42
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Wang ET, Rogel MA, García-de los Santos A, Martínez-Romero J, Cevallos MA, Martínez-Romero E. Rhizobium etli bv. mimosae, a novel biovar isolated from Mimosa affinis. Int J Syst Bacteriol 1999; 49 Pt 4:1479-91. [PMID: 10555329 DOI: 10.1099/00207713-49-4-1479] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fifty rhizobial isolates from root nodules of Mimosa affinis, a small leguminous plant native to Mexico, were identified as Rhizobium etli on the basis of the results of PCR-RFLP and RFLP analyses of small-subunit rRNA genes, multilocus enzyme electrophoresis and DNA-DNA homology. They are, however, a restricted group of lineages with low genetic diversity within the species. The isolates from M. affinis differed-from the R. etli strains that orginated from bean plants (Phaseolus vulgaris) in the size and replicator region of the symbiotic plasmid and in symbiotic-plasmid-borne traits such as nifH gene sequence and organization, melanin production and host specificity. A new biovar, bv. mimosae, is proposed within R. etli to encompass Rhizobium isolates obtained from M. affinis. The strains from common bean plants have been designated previously as R. etli bv. phaseoli. Strains of both R. etli biovars could nodulate P. vulgaris, but only those of bv. mimosae could form nitrogen-fixing nodules on Leucaena leucocephala.
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Affiliation(s)
- E T Wang
- Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional, Cuernavaca, Morelos, Mexico
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43
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Mandon K, Michel-Reydellet N, Encarnación S, Kaminski PA, Leija A, Cevallos MA, Elmerich C, Mora J. Poly-beta-hydroxybutyrate turnover in Azorhizobium caulinodans is required for growth and affects nifA expression. J Bacteriol 1998; 180:5070-6. [PMID: 9748438 PMCID: PMC107541 DOI: 10.1128/jb.180.19.5070-5076.1998] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Azorhizobium caulinodans is able to fix nitrogen in the free-living state and in symbiosis with the tropical legume Sesbania rostrata. The bacteria accumulate poly-beta-hydroxybutyrate (PHB) under both conditions. The structural gene for PHB synthase, phbC, was inactivated by insertion of an interposon. The mutant strains obtained were devoid of PHB, impaired in their growth properties, totally devoid of nitrogenase activity ex planta (Nif-), and affected in nucleotide pools and induced Fix- nodules devoid of bacteria. The Nif- phenotype was the consequence of the lack of nifA transcription. Nitrogenase activity was partially restored to a phbC mutant by constitutive expression of the nifA gene. However, this constitutive nifA expression had no effect on the nucleotide content or on growth of the phbC mutant. It is suggested that PHB is required for maintaining the reducing power of the cell and therefore the bacterial growth. These observations also suggest a new control of nifA expression to adapt nitrogen fixation to the availability of carbon and reducing equivalents.
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Affiliation(s)
- K Mandon
- Departamento de Ecología Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
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44
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Abstract
Pyruvate carboxylase (PYC) is a biotin-dependent enzyme catalyzing the anaplerotic conversion of pyruvate to oxaloacetate in Rhizobium etli strain CE3. A pyc::Tn5 mutant had severely reduced growth, or failed to grow on sugars, three-carbon organic acids or glycerol, consistent with these substrates being metabolized via pyruvate. Transconjugants expressing a pyc::beta-glucuronidase gene fusion had slightly increased apparent pyc transcription during growth on pyruvate as compared to succinate, similar to the modest carbon source dependent changes in PYC activity reported previously. Biotin supplementation of cultures growing on pyruvate dramatically increased PYC activity but not apparent pyc transcription. Bacteroids isolated from bean nodules did not contain detectable PYC activity while apparent pyc transcription occurred at a moderate level.
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Affiliation(s)
- M F Dunn
- Departamento de Ecología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.
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45
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Ramírez-Romero MA, Bustos P, Girard L, Rodríguez O, Cevallos MA, Dávila G. Sequence, localization and characteristics of the replicator region of the symbiotic plasmid of Rhizobium etli. Microbiology (Reading) 1997; 143 ( Pt 8):2825-2831. [PMID: 9274036 DOI: 10.1099/00221287-143-8-2825] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The replicator region of the symbiotic plasmid of Rhizobium etli CFN42 was cloned and sequenced. A plasmid derivative (pH3) harbouring a 5-6 kb HindIII fragment from the symbiotic plasmid was found to be capable of independent replication and eliminated the symbiotic plasmid when introduced into a R. etli CFNX101 strain (a recA derivative). The stability and the copy number of pH3 were the same as that of the symbiotic plasmid, indicating that the information required for stable replication and incompatibility resides in the 5.6 kb HindIII fragment. The sequence analysis of this fragment showed the presence of three ORFs similar in sequence analysis of this fragment showed the presence of three ORFs similar in sequence and organization to repA, repB and repC described for the replicator regions of the Agrobacterium plasmids pTiB653 and pRiA4b and for the R. leguminosarum cryptic plasmid pRL8JI. Hybridization studies showed that p42d-like replicator sequences are found in the symbiotic plasmids of other R. etli strains and in a 'cryptic' plasmid of R. tropici.
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Affiliation(s)
- Miguel A Ramírez-Romero
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Patricia Bustos
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Lourdes Girard
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Oscar Rodríguez
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Miguel A Cevallos
- Departamento de Ecología Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
| | - Guillermo Dávila
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Apartado Postal 565-A, Cuernavaca, Morelos, Mexico
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46
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Cevallos MA, Encarnación S, Leija A, Mora Y, Mora J. Genetic and physiological characterization of a Rhizobium etli mutant strain unable to synthesize poly-beta-hydroxybutyrate. J Bacteriol 1996; 178:1646-54. [PMID: 8626293 PMCID: PMC177850 DOI: 10.1128/jb.178.6.1646-1654.1996] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Rhizobium etli accumulates poly-beta-hydroxybutyrate (PHB) in symbiosis and in free life. PHB is a reserve material that serves as a carbon and/or electron sink when optimal growth conditions are not met. It has been suggested that in symbiosis PHB can prolong nitrogen fixation until the last stages of seed development, but experiments to test this proposition have not been done until now. To address these questions in a direct way, we constructed an R. etli PHB-negative mutant by the insertion of an Omega-Km interposon within the PHB synthase structural gene (phaC). The identification and sequence of the R. etli phaC gene are also reported here. Physiological studies showed that the PHB-negative mutant strain was unable to synthesize PHB and excreted more lactate, acetate, pyruvate, beta-hydroxybutyrate, fumarate, and malate than the wild-type strain. The NAD+/NADH ratio in the mutant strain was lower than that in the parent strain. The oxidative capacity of the PHB-negative mutant was reduced. Accordingly, the ability to grow in minimal medium supplemented with glucose or pyruvate was severely diminished in the mutant strain. We propose that in free life PHB synthesis sequesters reductive power, allowing the tricarboxylic acid cycle to proceed under conditions in which oxygen is a limiting factor. In symbiosis with Phaseolus vulgaris, the PHB-negative mutant induced nodules that prolonged the capacity to fix nitrogen.
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Affiliation(s)
- M A Cevallos
- Departamento de Ecología Molecular, Universidad Nacional Autónoma de México, Morelos, México
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47
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Cevallos MA, Porta H, Alagón AC, Lizardi PM. Sequence of the 5.8S ribosomal gene of pathogenic and non-pathogenic isolates of Entamoeba histolytica. Nucleic Acids Res 1993; 21:355. [PMID: 8441643 PMCID: PMC309116 DOI: 10.1093/nar/21.2.355] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- M A Cevallos
- Departamento de Bioquímica, Universidad Nacional Autónoma de México, Cuernavaca
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48
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Cevallos MA, Navarro-Duque C, Varela-Julia M, Alagon AC. Molecular mass determination and assay of venom hyaluronidases by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Toxicon 1992; 30:925-30. [PMID: 1523685 DOI: 10.1016/0041-0101(92)90392-i] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We describe a procedure for molecular mass determination of hyaluronidases present in animal venoms from different families. Hyaluronidases can be revealed, following their electrophoretic separation in sodium dodecyl sulfate-polyacrylamide gel containing hyaluronic acid, by incubating the gel in Triton X-100 to remove sodium dodecyl sulfate and restore in situ enzyme activity. This method allows the detection of as little as 0.025 turbidity-reducing units after 2 hr incubation. All the hyaluronidases from the analyzed invertebrate venoms had a mass below 50,000 and showed only one component, while those from vertebrate venoms were more than 60,000 and in many instances contained more than one form.
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Affiliation(s)
- M A Cevallos
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mor
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49
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Cevallos MA, Vázquez M, Dávalos A, Espín G, Sepúlveda J, Quinto C. Characterization of Rhizobium phaseoli Sym plasmid regions involved in nodule morphogenesis and host-range specificity. Mol Microbiol 1989; 3:879-89. [PMID: 2552255 DOI: 10.1111/j.1365-2958.1989.tb00237.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two nodulation regions from the symbiotic plasmid (pSym) of Rhizobium phaseoli CE-3 were identified. The two regions were contained in overlapping cosmids pSM927 and pSM991. These cosmids, in a R. phaseoli pSym-cured strain background, induced ineffective nodules on Phaseolus vulgaris roots. Transconjugants of Rhizobium meliloti harbouring pSM991 induced nodule-like structures on bean roots, suggesting that this cosmid contains host-range determinants. Analysis of deletions and insertional mutations in the sequences of pSM991 indicated that the genes responsible for the induction and development of nodules in P. vulgaris are organized in two regions 20 kb apart. One region, located in a 6.8 kb EcoRI fragment, includes the common nodABC genes. The other region, located in a 3.5 kb EcoRI fragment, contains information required for host-range determination.
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Affiliation(s)
- M A Cevallos
- Departamento de Biología Molecular de Plantas, Centro de Investigacíon sobre Fijación de Nitrógeno, Morelos, México
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50
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Abstract
Rhizobium phaseoli CFN42 DNA was mutated by random insertion of Tn5 from suicide plasmid pJB4JI to obtain independently arising strains that were defective in symbiosis with Phaseolus vulgaris but grew normally outside the plant. When these mutants were incubated with the plant, one did not initiate visible nodule tissue (Nod-), seven led to slow nodule development (Ndv), and two led to superficially normal early nodule development but lacked symbiotic nitrogenase activity (Sna-). The Nod- mutant lacked the large transmissible indigenous plasmid pCFN42d that has homology to Klebsiella pneumoniae nitrogenase (nif) genes. The other mutants had normal plasmid content. In the two Sna- mutants and one Ndv mutant, Tn5 had inserted into plasmid pCFN42d outside the region of nif homology. The insertions of the other Ndv mutants were apparently in the chromosome. They were not in plasmids detected on agarose gels, and, in contrast to insertions on indigenous plasmids, they were transmitted in crosses to wild-type strain CFN42 at the same frequency as auxotrophic markers and with the same enhancement of transmission by conjugation plasmid R68.45. In these Ndv mutants the Tn5 insertions were the same as or very closely linked to mutations causing the Ndv phenotype. However, in two mutants with Tn5 insertions on plasmid pCFN42d, an additional mutation on the same plasmid, rather than Tn5, was responsible for the Sna- or Ndv phenotype. When plasmid pJB4JI was transferred to two other R. phaseoli strains, analysis of symbiotic mutants was complicated by Tn5-containing deleted forms of pJB4JI that were stably maintained.
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