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Zhao X, Hendriks M, Deleu E, Spanoghe P, Höfte M, van Overbeek L, Uyttendaele M. Prevalence, attachment ability and strength of the biological control agent Bacillus thuringiensis on tomato. Food Microbiol 2023; 112:104235. [PMID: 36906306 DOI: 10.1016/j.fm.2023.104235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023]
Abstract
Bacillus thuringiensis (Bt) is commonly used as a biological control agent (BCA) to control insect pests in edible plant production and can as such be introduced into the food chain of fresh produce. Using standard food diagnostics Bt will be detected and reported as presumptive B. cereus. Tomato plants are often sprayed with Bt biopesticides for insect control, thus these Bt BCAs can also reach the tomato fruits and persist until consumption. In this study, vine tomatoes from the retail in Belgium (Flanders) were investigated for the occurrence and residual numbers of presumptive B. cereus and Bt. Of 109 tomato samples, 61 (56%) were tested positive for presumptive B. cereus. Of the presumptive B. cereus isolates (n = 213) recovered from these samples, 98% were identified as Bt by the production of parasporal crystals. Further quantitative real-time PCR assays on a subselection of Bt isolates (n = 61) showed that 95% of Bt isolates were indistinguishable from Bt biopesticide strains that are approved to be used on crops in the EU. Furthermore, the attachment strength of tested Bt biopesticide strains showed easier wash-off properties if using the commercial Bt granule formulation than the unformulated lab-cultured Bt or B. cereus spore suspensions.
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Affiliation(s)
- Xingchen Zhao
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium.
| | - Marc Hendriks
- Biointeractions and Plant Health, Wageningen University & Research, P.O. Box 16, 6700, AA Wageningen, the Netherlands
| | - Emily Deleu
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
| | - Pieter Spanoghe
- Laboratory of Crop Protection Chemistry, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
| | - Leo van Overbeek
- Biointeractions and Plant Health, Wageningen University & Research, P.O. Box 16, 6700, AA Wageningen, the Netherlands
| | - Mieke Uyttendaele
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, 9000, Ghent, Belgium
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2
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Jneid R, Loudhaief R, Zucchini-Pascal N, Nawrot-Esposito MP, Fichant A, Rousset R, Bonis M, Osman D, Gallet A. Bacillus thuringiensis toxins divert progenitor cells toward enteroendocrine fate by decreasing cell adhesion with intestinal stem cells in Drosophila. eLife 2023; 12:80179. [PMID: 36847614 PMCID: PMC9977296 DOI: 10.7554/elife.80179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 02/05/2023] [Indexed: 03/01/2023] Open
Abstract
Bacillus thuringiensis subsp. kurstaki (Btk) is a strong pathogen toward lepidopteran larvae thanks to specific Cry toxins causing leaky gut phenotypes. Hence, Btk and its toxins are used worldwide as microbial insecticide and in genetically modified crops, respectively, to fight crop pests. However, Btk belongs to the B. cereus group, some strains of which are well known human opportunistic pathogens. Therefore, ingestion of Btk along with food may threaten organisms not susceptible to Btk infection. Here we show that Cry1A toxins induce enterocyte death and intestinal stem cell (ISC) proliferation in the midgut of Drosophila melanogaster, an organism non-susceptible to Btk. Surprisingly, a high proportion of the ISC daughter cells differentiate into enteroendocrine cells instead of their initial enterocyte destiny. We show that Cry1A toxins weaken the E-Cadherin-dependent adherens junction between the ISC and its immediate daughter progenitor, leading the latter to adopt an enteroendocrine fate. Hence, although not lethal to non-susceptible organisms, Cry toxins can interfere with conserved cell adhesion mechanisms, thereby disrupting intestinal homeostasis and endocrine functions.
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Affiliation(s)
- Rouba Jneid
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese UniversityTripoliLebanon
| | | | | | | | - Arnaud Fichant
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & SafetyMaisons-AlfortFrance
| | | | - Mathilde Bonis
- Laboratory for Food Safety, University Paris-Est, French Agency for Food, Environmental and Occupational Health & SafetyMaisons-AlfortFrance
| | - Dani Osman
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese UniversityTripoliLebanon
| | - Armel Gallet
- Universite Cote d'Azur, CNRS, INRAESophia AntipolisFrance
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3
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Zhao X, Zervas A, Hendriks M, Rajkovic A, van Overbeek L, Hendriksen NB, Uyttendaele M. Identification and characterization of Bacillus thuringiensis and other Bacillus cereus group isolates from spinach by whole genome sequencing. Front Microbiol 2022; 13:1030921. [PMID: 36569082 PMCID: PMC9771606 DOI: 10.3389/fmicb.2022.1030921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/09/2022] [Indexed: 12/05/2022] Open
Abstract
Bacillus thuringiensis (Bt), used as a biological control agent (BCA), can persist on plants, and from there can be introduced into the final food product. In routine food safety diagnostics, these Bt residues cannot be distinguished from natural populations of Bacillus cereus present in plants and all are enumerated as "presumptive B. cereus." In this study, information on eventual use of Bt biopesticides, brand, application times and intervals provided by three food processing companies in Belgium, were integrated with quantitative data on presumptive B. cereus measured from fresh to frozen food products. This information together with data on genomic similarity obtained via whole genome sequencing (WGS) and cry gene profiling using a quantitative real-time PCR (qPCR) assay, confirmed that six out of 11 Bt isolates originated from the applied Bt biocontrol products. These identified Bt strains were shown to carry enterotoxin genes (nhe, hbl, cytK-2) and express Hbl enterotoxin in vitro. It was also noted that these Bt biopesticide strains showed no growth at standard refrigeration temperatures and a low or moderate biofilm-forming ability and cytotoxic activity. Our results also showed that the use of Bt as a BCA on spinach plants in the field led to higher residual counts of Bt in spinach (fresh or frozen) in the food supply chain, but the residual counts exceeding at present commonly assumed safety limit of 105 CFU/g was only found in one fresh spinach sample. It is therefore recommended to establish a pre-harvest interval for Bt biopesticide application in the field to lower the likelihood of noncompliance to the generic B. cereus safety limit. Furthermore, WGS was found to be the best way to identify Bt biopesticide isolates at the strain level for foodborne outbreaks and clinical surveillance. The developed qPCR assay for screening on the presence of cry genes in presumptive B. cereus can be applied as a rapid routine test as an amendment to the already existing test on Bt crystal proteins determined via phase-contrast microscopy.
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Affiliation(s)
- Xingchen Zhao
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium,*Correspondence: Xingchen Zhao,
| | - Athanasios Zervas
- Department of Environmental Science, Aarhus University, Roskilde, Denmark
| | - Marc Hendriks
- Wageningen Plant Research, Wageningen University and Research, Wageningen, Netherlands
| | - Andreja Rajkovic
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Leo van Overbeek
- Wageningen Plant Research, Wageningen University and Research, Wageningen, Netherlands
| | | | - Mieke Uyttendaele
- Food Microbiology and Food Preservation Research Unit, Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Hinnekens P, Fayad N, Gillis A, Mahillon J. Conjugation across Bacillus cereus and kin: A review. Front Microbiol 2022; 13:1034440. [PMID: 36406448 PMCID: PMC9673590 DOI: 10.3389/fmicb.2022.1034440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/11/2022] [Indexed: 11/06/2022] Open
Abstract
Horizontal gene transfer (HGT) is a major driving force in shaping bacterial communities. Key elements responsible for HGT are conjugation-like events and transmissible plasmids. Conjugative plasmids can promote their own transfer as well as that of co-resident plasmids. Bacillus cereus and relatives harbor a plethora of plasmids, including conjugative plasmids, which are at the heart of the group species differentiation and specification. Since the first report of a conjugation-like event between strains of B. cereus sensu lato (s.l.) 40 years ago, many have studied the potential of plasmid transfer across the group, especially for plasmids encoding major toxins. Over the years, more than 20 plasmids from B. cereus isolates have been reported as conjugative. However, with the increasing number of genomic data available, in silico analyses indicate that more plasmids from B. cereus s.l. genomes present self-transfer potential. B. cereus s.l. bacteria occupy diverse environmental niches, which were mimicked in laboratory conditions to study conjugation-related mechanisms. Laboratory mating conditions remain nonetheless simplistic compared to the complex interactions occurring in natural environments. Given the health, economic and ecological importance of strains of B. cereus s.l., it is of prime importance to consider the impact of conjugation within this bacterial group.
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Affiliation(s)
- Pauline Hinnekens
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Louvain-la-Neuve, Belgium
| | - Nancy Fayad
- Multi-Omics Laboratory, School of Pharmacy, Lebanese American University, Byblos, Lebanon
| | - Annika Gillis
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Louvain-la-Neuve, Belgium
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Earth and Life Institute, Louvain-la-Neuve, Belgium
- *Correspondence: Jacques Mahillon,
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Takahashi N, Nagai S, Tomimatsu Y, Saito A, Kaneta N, Tsujimoto Y, Tamura H. Simultaneous Discrimination of Cereulide-Producing Bacillus cereus and Psychrotolerant B. cereus Group by Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry. J Food Prot 2022; 85:1192-1202. [PMID: 35687734 DOI: 10.4315/jfp-21-450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/01/2022] [Indexed: 11/11/2022]
Abstract
ABSTRACT Cereulide-producing Bacillus cereus, which causes foodborne illnesses with vomiting, and psychrotolerant B. cereus group strains such as Bacillus mycoides, which can grow at ≥7°C and cause spoilage of refrigerated foods, are significant concerns for the food industry. Rapid and simple methods to discriminate the cereulide-producing B. cereus and psychrotolerant B. cereus group strains from other B. cereus group strains are needed. We developed a novel, rapid, and simple method with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis for simultaneous discrimination of these two groups from other B. cereus group strains. A potassium adduct of cereulide was used to detect cereulide-producing B. cereus, and three ribosomal subunit proteins (L30, S16, and S20) were used to detect psychrotolerant B. cereus group. A total of 51 B. cereus group strains were analyzed by MALDI-TOF MS. The biomarkers allowed successful discrimination of 16 cereulide-producing B. cereus and 15 psychrotolerant B. cereus group strains from other B. cereus group strains. The results showed that this MALDI-TOF MS analysis allows simultaneous discrimination of cereulide-producing B. cereus and psychrotolerant B. cereus group strains from other B. cereus group strains. This efficient method has the potential to be a valuable tool for ensuring food safety. HIGHLIGHTS
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Affiliation(s)
- Naomi Takahashi
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan
| | - Satomi Nagai
- Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, Aichi 468-8502, Japan
| | - Yumiko Tomimatsu
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan
| | - Ayumi Saito
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan
| | - Naoko Kaneta
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan
| | - Yoshinori Tsujimoto
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1 Nanakuni, Hachioji, Tokyo, 192-0919, Japan
| | - Hiroto Tamura
- Faculty of Agriculture, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, Aichi 468-8502, Japan
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Delanthabettu A, Narasimhappa NS, Ramaswamy A, Mallesh MH, Nagarajappa N, Govind G. Molecular Characterization of Native Bacillus thuringiensis Strains from Root Nodules with Toxicity Against the Fall Armyworm (FAW, Spodoptera frugiperda) and Brinjal Ash Weevil (Myllocerus subfasciatus). Curr Microbiol 2022; 79:274. [PMID: 35907079 DOI: 10.1007/s00284-022-02951-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 06/24/2022] [Indexed: 11/28/2022]
Abstract
The fall armyworm is an exotic pest which destroys a wide variety of crops Querywhereas the brinjal ash weevil is a serious pest of eggplant and other solanaceous vegetables. The goal of this research is to find a sustainable and ecologically friendly bio-control agent for managing FAW and brinjal ash weevils. Twelve natural Bacillus thuringiensis strains were isolated from cowpea root nodules, and the Gram-positive cells with characteristic Bt crystal structures were discovered using phase contrast and scanning electron microscopy. There were bipyramidal, cuboidal, rhombus, and spherical crystals. The Bt cry gene content was characterized by PCR analysis, which revealed the presence of cry1, cry1I, cry3, cry7, cry7,8, cry14, cry26, and cry55 genes. The identity of Bt was confirmed by cloning and sequencing the cry genes. In the nucleotide sequences, no pseudo genes or indels were found in cry sequences. SDS-PAGE examination indicated the presence of bands ranging in size from 13 to 130 kDa, with 50-60 kDa being the most common. When compared to the control, the new native Bt strains were lethal, with pathogenicity ranging from 93 to 100% against S. frugiperda larvae and M. subfasciatus adults. The studies revealed that the native strains with conserved regions of 16S rRNA genes were compared to NCBI database sequences and classified as native Bt strains with 99-100% similarity to known Bt strains. In conclusion, native Bt strains from cowpea root nodules were shown to have bio-insecticidal activity against fall armyworm larvae and brinjal ash weevil adults.
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Affiliation(s)
| | | | - Asokan Ramaswamy
- Division of Basic Sciences, ICAR-Indian Institute of Horticultural Research, Hesaraghatta Lake Post, Bangalore, 560089, India
| | | | - Nethra Nagarajappa
- Seed Technology Research Unit, AICRP on Seeds (Crops), UAS, GKVK, Bangalore, 560065, India
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7
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Nawrot-Esposito MP, Babin A, Pasco M, Poirié M, Gatti JL, Gallet A. Bacillus thuringiensis Bioinsecticides Induce Developmental Defects in Non-Target Drosophila melanogaster Larvae. INSECTS 2020; 11:E697. [PMID: 33066180 PMCID: PMC7601982 DOI: 10.3390/insects11100697] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022]
Abstract
Bioinsecticides made from the bacterium Bacillus thuringiensis (Bt) are the bestselling bioinsecticide worldwide. Among Bt bioinsecticides, those based on the strain Bt subsp. kurstaki (Btk) are widely used in farming to specifically control pest lepidopteran larvae. Although there is much evidence of the lack of acute lethality of Btk products for non-target animals, only scarce data are available on their potential non-lethal developmental adverse effects. Using a concentration that could be reached in the field upon sprayings, we show that Btk products impair growth and developmental time of the non-target dipteran Drosophila melanogaster. We demonstrate that these effects are mediated by the synergy between Btk bacteria and Btk insecticidal toxins. We further show that Btk bioinsecticides trigger intestinal cell death and alter protein digestion without modifying the food intake and feeding behavior of the larvae. Interestingly, these harmful effects can be mitigated by a protein-rich diet or by adding the probiotic bacterium Lactobacillus plantarum into the food. Finally, we unravel two new cellular mechanisms allowing the larval midgut to maintain its integrity upon Btk aggression: First the flattening of surviving enterocytes and second, the generation of new immature cells arising from the adult midgut precursor cells. Together, these mechanisms participate to quickly fill in the holes left by the dying enterocytes.
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Affiliation(s)
| | | | | | | | | | - Armel Gallet
- Université Côte d’Azur, CNRS, INRAE, ISA, UMR CNRS 7254/INRAE 1355/UCA, 400 route des Chappes, BP 167, 06903 Sophia Antipolis CEDEX, France; (M.-P.N.-E.); (A.B.); (M.P.); (M.P.); (J.-L.G.)
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8
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Babin A, Nawrot-Esposito MP, Gallet A, Gatti JL, Poirié M. Differential side-effects of Bacillus thuringiensis bioinsecticide on non-target Drosophila flies. Sci Rep 2020; 10:16241. [PMID: 33004867 PMCID: PMC7529784 DOI: 10.1038/s41598-020-73145-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 09/07/2020] [Indexed: 01/22/2023] Open
Abstract
Bioinsecticides based on Bacillus thuringiensis (Bt) spores and toxins are increasingly popular alternative solutions to control insect pests, with potential impact of their accumulation in the environment on non-target organisms. Here, we tested the effects of chronic exposure to commercial Bt formulations (Bt var. kurstaki and israelensis) on eight non-target Drosophila species present in Bt-treated areas, including D. melanogaster (four strains). Doses up to those recommended for field application (~ 106 Colony Forming Unit (CFU)/g fly medium) did not impact fly development, while no fly emerged at ≥ 1000-fold this dose. Doses between 10- to 100-fold the recommended one increased developmental time and decreased adult emergence rates in a dose-dependent manner, with species-and strain-specific effect amplitudes. Focusing on D. melanogaster, development alterations were due to instar-dependent larval mortality, and the longevity and offspring number of adult flies exposed to bioinsecticide throughout their development were moderately influenced. Our data also suggest a synergy between the formulation compounds (spores, cleaved toxins, additives) might induce the bioinsecticide effects on larval development. Although recommended doses had no impact on non-target Drosophila species, misuse or local environmental accumulation of Bt bioinsecticides could have side-effects on fly populations with potential implications for their associated communities.
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Affiliation(s)
- Aurélie Babin
- Institut Sophia Agrobiotech, Université Côte D'Azur, INRAE, CNRS, ISA, 400 route des chappes, 06903, Sophia Antipolis, France
| | - Marie-Paule Nawrot-Esposito
- Institut Sophia Agrobiotech, Université Côte D'Azur, INRAE, CNRS, ISA, 400 route des chappes, 06903, Sophia Antipolis, France
| | - Armel Gallet
- Institut Sophia Agrobiotech, Université Côte D'Azur, INRAE, CNRS, ISA, 400 route des chappes, 06903, Sophia Antipolis, France
| | - Jean-Luc Gatti
- Institut Sophia Agrobiotech, Université Côte D'Azur, INRAE, CNRS, ISA, 400 route des chappes, 06903, Sophia Antipolis, France.
| | - Marylène Poirié
- Institut Sophia Agrobiotech, Université Côte D'Azur, INRAE, CNRS, ISA, 400 route des chappes, 06903, Sophia Antipolis, France
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9
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Takahashi N, Nagai S, Fujita A, Ido Y, Kato K, Saito A, Moriya Y, Tomimatsu Y, Kaneta N, Tsujimoto Y, Tamura H. Discrimination of psychrotolerant Bacillus cereus group based on MALDI-TOF MS analysis of ribosomal subunit proteins. Food Microbiol 2020; 91:103542. [PMID: 32539947 DOI: 10.1016/j.fm.2020.103542] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/28/2020] [Accepted: 05/03/2020] [Indexed: 02/06/2023]
Abstract
Psychrotolerant species of the Bacillus cereus group, Bacillus mycoides and Bacillus weihenstephanensis, can grow at ≥ 7 °C and are significant concerns for the food industry due to their ability to cause spoilage of refrigerated food. In addition to that, some strains of B. weihenstephanensis can produce emetic toxin, namely cereulide, which is known to cause vomiting. Therefore, rapid and simple methods to discriminate psychrotolerant B. cereus group species are crucial. Here, matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) and the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum (S10-GERMS) method were used to discriminate psychrotolerant species of the B. cereus group based on a set of four ribosomal subunit proteins (S10, S16, S20 and L30). A total of 36 strains of B. cereus group were cultured on LB agar, and analyzed by MALDI-TOF MS. The four biomarkers successfully discriminated 12 strains of psychrotolerant species from mesophilic species of the B. cereus group. Furthermore, the four biomarkers also classified some Bacillus thuringiensis strains. MALDI-TOF MS analysis using the S10-GERMS method allowed simple and rapid discrimination of psychrotolerant species of the B. cereus group from other mesophilic species. This method has a possibility to enable manufacturers and distributors of refrigerated foods to control psychrotolerant species of the B. cereus group effectively.
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Affiliation(s)
- Naomi Takahashi
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan.
| | - Satomi Nagai
- Faculty of Agriculture, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya, Aichi, 468-8502, Japan
| | - Akane Fujita
- Faculty of Agriculture, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya, Aichi, 468-8502, Japan
| | - Yousuke Ido
- Faculty of Agriculture, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya, Aichi, 468-8502, Japan
| | - Kenji Kato
- Faculty of Agriculture, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya, Aichi, 468-8502, Japan
| | - Ayumi Saito
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan
| | - Yuka Moriya
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan
| | - Yumiko Tomimatsu
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan
| | - Naoko Kaneta
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan
| | - Yoshinori Tsujimoto
- Food Quality and Safety Research Laboratories, Meiji Co., Ltd., 1-29-1, Nanakuni, Hachiouji, Tokyo, 192-0919, Japan
| | - Hiroto Tamura
- Faculty of Agriculture, Meijo University, 1-501, Shiogamaguchi, Tempaku-ku, Nagoya, Aichi, 468-8502, Japan.
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10
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Carroll LM, Wiedmann M, Kovac J. Proposal of a Taxonomic Nomenclature for the Bacillus cereus Group Which Reconciles Genomic Definitions of Bacterial Species with Clinical and Industrial Phenotypes. mBio 2020; 11:e00034-20. [PMID: 32098810 PMCID: PMC7042689 DOI: 10.1128/mbio.00034-20] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 01/15/2020] [Indexed: 02/07/2023] Open
Abstract
The Bacillus cereus group comprises numerous closely related species, including bioterrorism agent B. anthracis, foodborne pathogen B. cereus, and biopesticide B. thuringiensis Differentiating organisms capable of causing illness or death from those used in industry is essential for risk assessment and outbreak preparedness. However, current species definitions facilitate species-phenotype incongruences, particularly when horizontally acquired genes are responsible for a phenotype. Using all publicly available B. cereus group genomes (n = 2,231), we show that current species definitions lead to overlapping genomospecies clusters, in which 66.2% of genomes belong to multiple genomospecies at a conventional 95 average nucleotide identity (ANI) genomospecies threshold. A genomospecies threshold of ≈92.5 ANI is shown to reflect a natural gap in genome similarity for the B. cereus group, and medoid genomes identified at this threshold are shown to yield resolvable genomospecies clusters with minimal overlap (six of 2,231 genomes assigned to multiple genomospecies; 0.269%). We thus propose a nomenclatural framework for the B. cereus group which accounts for (i) genomospecies using resolvable genomospecies clusters obtained at ≈92.5 ANI, (ii) established lineages of medical importance using a formal collection of subspecies names, and (iii) heterogeneity of clinically and industrially important phenotypes using a formalized and extended collection of biovar terms. We anticipate that the proposed nomenclature will remain interpretable to clinicians, without sacrificing genomic species definitions, which can in turn aid in pathogen surveillance; early detection of emerging, high-risk genotypes; and outbreak preparedness.IMPORTANCE Historical species definitions for many prokaryotes, including pathogens, have relied on phenotypic characteristics that are inconsistent with genome evolution. This scenario forces microbiologists and clinicians to face a tradeoff between taxonomic rigor and clinical interpretability. Using the Bacillus cereus group as a model, a conceptual framework for the taxonomic delineation of prokaryotes which reconciles genomic definitions of species with clinically and industrially relevant phenotypes is presented. The nomenclatural framework outlined here serves as a model for genomics-based bacterial taxonomy that moves beyond arbitrarily set genomospecies thresholds while maintaining congruence with phenotypes and historically important species names.
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Affiliation(s)
- Laura M Carroll
- Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Jasna Kovac
- Department of Food Science, The Pennsylvania State University, University Park, Pennsylvania, USA
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11
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Abstract
The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis, B. cereus, and B. thuringiensis, are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.
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Rossi GAM, Silva HO, Aguilar CEG, Rochetti AL, Pascoe B, Méric G, Mourkas E, Hitchings MD, Mathias LA, de Azevedo Ruiz VL, Fukumasu H, Sheppard SK, Vidal AMC. Comparative genomic survey of Bacillus cereus sensu stricto isolates from the dairy production chain in Brazil. FEMS Microbiol Lett 2019; 365:4780294. [PMID: 29390131 DOI: 10.1093/femsle/fnx283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/23/2017] [Indexed: 12/20/2022] Open
Abstract
The genomes of 262 Bacillus cereus isolates were analyzed including 69 isolates sampled from equipment, raw milk and dairy products from Brazil. The population structure of isolates showed strains belonging to known phylogenetic groups II, III, IV, V and VI. Almost all the isolates obtained from dairy products belonged to group III. Investigation of specific alleles revealed high numbers of isolates carrying toxin-associated genes including cytK (53.62%), hblA (59.42%), hblC (44.93%), hblD (53.62%), nheA (84.06%), nheB (89.86%) and nheC (84.06%) with isolates belonging to groups IV and V having significant higher prevalence of hblACD and group IV of CytK genes. Strains from dairy products had significantly lower prevalence of CytK and hblACD genes compared to isolates from equipment and raw milk/bulk tanks. Genes related to sucrose metabolism were detected at higher frequency in isolates obtained from raw milk compared to strains from equipment and utensils. The population genomic analysis demonstrated the diversity of strains and variability of putative function among B. cereus group isolates in Brazilian dairy production, with large numbers of strains potentially able to cause foodborne illness. This detailed information will contribute to targeted interventions to reduce milk contamination and spoilage associated with B. cereus in Brazil.
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Affiliation(s)
- Gabriel Augusto Marques Rossi
- Departamento de Medicina Veterinária Preventiva e Reprodução Animal, UNESP - Univ. Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias (FCAV), Via de acesso Paulo Castellane, s/n, CEP 14884-900 Jaboticabal, São Paulo, Brazil
| | - Higor Oliveira Silva
- Departamento de Medicina Veterinária Preventiva e Reprodução Animal, UNESP - Univ. Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias (FCAV), Via de acesso Paulo Castellane, s/n, CEP 14884-900 Jaboticabal, São Paulo, Brazil
| | - Carlos Eduardo Gamero Aguilar
- Departamento de Medicina Veterinária Preventiva e Reprodução Animal, UNESP - Univ. Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias (FCAV), Via de acesso Paulo Castellane, s/n, CEP 14884-900 Jaboticabal, São Paulo, Brazil
| | - Arina Lázaro Rochetti
- Departamento de Medicina Veterinária, Avenida Duque de Caxias Norte 225, Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos (FZEA), CEP 13635-900 Pirassununga, São Paulo, Brazil
| | - Ben Pascoe
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, 4 South, Lab 0.39, Claverton Down, BA2 7AY Bath, UK
| | - Guillaume Méric
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, 4 South, Lab 0.39, Claverton Down, BA2 7AY Bath, UK
| | - Evangelos Mourkas
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, 4 South, Lab 0.39, Claverton Down, BA2 7AY Bath, UK
| | | | - Luis Antonio Mathias
- Departamento de Medicina Veterinária Preventiva e Reprodução Animal, UNESP - Univ. Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias (FCAV), Via de acesso Paulo Castellane, s/n, CEP 14884-900 Jaboticabal, São Paulo, Brazil
| | - Vera Letticie de Azevedo Ruiz
- Departamento de Medicina Veterinária, Avenida Duque de Caxias Norte 225, Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos (FZEA), CEP 13635-900 Pirassununga, São Paulo, Brazil
| | - Heidge Fukumasu
- Departamento de Medicina Veterinária, Avenida Duque de Caxias Norte 225, Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos (FZEA), CEP 13635-900 Pirassununga, São Paulo, Brazil
| | - Samuel K Sheppard
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, 4 South, Lab 0.39, Claverton Down, BA2 7AY Bath, UK
| | - Ana Maria Centola Vidal
- Departamento de Medicina Veterinária, Avenida Duque de Caxias Norte 225, Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos (FZEA), CEP 13635-900 Pirassununga, São Paulo, Brazil
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13
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Hachfi S, Benguettat O, Gallet A. Hypochlorous Acid Staining with R19-S in the Drosophila Intestine upon Ingestion of Opportunistic Bacteria. Bio Protoc 2019; 9:e3246. [PMID: 33654772 DOI: 10.21769/bioprotoc.3246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 11/02/2022] Open
Abstract
The intestine is endowed with an innate immune system that is required to fight any exogenous bacteria that are swallowed along with the food. The first line of defense that is mounted by the gut epithelium is the release of immune Reactive Oxygen Species (ROS), such as hypochlorous acid (HOCl), into the lumen. HOCl is produced within 1.5 h of bacterial ingestion and is very labile once released. Therefore, to monitor HOCl production upon ingestion of allochthonous bacteria, one needs a detection system that can quickly and efficiently detect HOCl production in the intestine. While most of the ROS-sensitive probes available in the market detect all kinds of ROS without any distinction, the R19-S fluorescent probe has been developed to specifically detect HOCl. Here, we describe a protocol to monitor HOCl production using this probe in the gut lumen of adult Drosophila upon ingestion of the opportunistic bacteria Bacillus thuringiensis.
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Affiliation(s)
- Salma Hachfi
- Universite Cote d'Azur, CNRS, INRA, ISA, France.,Institut Sophia Agrobiotech, UMR CNRS 7254/INRA 1355/UNS, 400 route des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France
| | - Olivia Benguettat
- Universite Cote d'Azur, CNRS, INRA, ISA, France.,Institut Sophia Agrobiotech, UMR CNRS 7254/INRA 1355/UNS, 400 route des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France
| | - Armel Gallet
- Universite Cote d'Azur, CNRS, INRA, ISA, France.,Institut Sophia Agrobiotech, UMR CNRS 7254/INRA 1355/UNS, 400 route des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France
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14
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Heu K, Gendrin M. [Mosquito microbiota and its influence on disease vectorial transmission]. Biol Aujourdhui 2019; 212:119-136. [PMID: 30973141 DOI: 10.1051/jbio/2019003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 01/23/2023]
Abstract
Mosquitoes (Diptera: Culicidae) are found worldwide. Around 100 among 3500 mosquito species are known to be vectors of parasites and viruses, responsible for infectious diseases including malaria and dengue. Mosquitoes host diverse microbial communities that influence disease transmission, either by direct interference or via affecting host immunity and physiology. These microbial communities are present within diverse tissues, including the digestive tract, and vary depending on the sex of the mosquito, its developmental stage, and ecological factors. This review summarizes the current knowledge about the mosquito microbiota, defined as a community of commensal, symbiotic or pathogenic microbes harboured by a host. We first describe the current knowledge on the diversity of the microbiota, that includes bacteria, fungi, parasites and viruses and on its modes of acquisition throughout the mosquito life cycle. We then focus on microbial interactions within the mosquito gut, which notably affect vector competence, and on host-microbe interactions affecting mosquito fitness. Finally, we discuss current or potential methods based on the use of microbes or microbial products to interfere with pathogen transmission or to reduce mosquito lifespan and reproduction.
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Affiliation(s)
- Katy Heu
- Groupe « Microbiote des Insectes Vecteurs », Institut Pasteur de la Guyane, Cayenne, Guyane, France
| | - Mathilde Gendrin
- Groupe « Microbiote des Insectes Vecteurs », Institut Pasteur de la Guyane, Cayenne, Guyane, France - Département « Parasites et Insectes Vecteurs », Institut Pasteur, Paris, France
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15
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Benguettat O, Jneid R, Soltys J, Loudhaief R, Brun-Barale A, Osman D, Gallet A. The DH31/CGRP enteroendocrine peptide triggers intestinal contractions favoring the elimination of opportunistic bacteria. PLoS Pathog 2018; 14:e1007279. [PMID: 30180210 PMCID: PMC6138423 DOI: 10.1371/journal.ppat.1007279] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/14/2018] [Accepted: 08/13/2018] [Indexed: 02/06/2023] Open
Abstract
The digestive tract is the first organ affected by the ingestion of foodborne bacteria. While commensal bacteria become resident, opportunistic or virulent bacteria are eliminated from the gut by the local innate immune system. Here we characterize a new mechanism of defense, independent of the immune system, in Drosophila melanogaster. We observed strong contractions of longitudinal visceral muscle fibers for the first 2 hours following bacterial ingestion. We showed that these visceral muscle contractions are induced by immune reactive oxygen species (ROS) that accumulate in the lumen and depend on the ROS-sensing TRPA1 receptor. We then demonstrate that both ROS and TRPA1 are required in a subset of anterior enteroendocrine cells for the release of the DH31 neuropeptide which activates its receptor in the neighboring visceral muscles. The resulting contractions of the visceral muscles favors quick expulsion of the bacteria, limiting their presence in the gut. Our results unveil a precocious mechanism of defense against ingested opportunistic bacteria, whether they are Gram-positive like Bacillus thuringiensis or Gram-negative like Erwinia carotovora carotovora. Finally, we found that the human homolog of DH31, CGRP, has a conserved function in Drosophila. The intestine is the first barrier to fight non-commensal bacteria ingested along with the food. The innate immune system is the main mean mounted by the gut lining in response to ill-causing bacteria to avoid detrimental impact. Intestinal cells produce chlorine bleach and antimicrobial peptides that destroy exogenous bacteria. Here, we identified and characterized a new mechanism of gut defense that occurs rapidly after ingestion of exogenous bacteria. We found that the enteroendocrine cells perceive the presence of chlorine bleach in the lumen thanks to a sensor. This sensor promotes a calcium flux within enteroendocrine cells that allows the release of a hormone. This hormone acts locally on the visceral muscle surrounding the intestine by provoking its strong contractions (or spasms). We show that these strong but brief visceral contractions are helping to the quick expulsion of the ingested bacteria thus limiting their potential detrimental impact on the intestine. Markedly, the bleach-sensor is well known to be involved in pain. Therefore we have deciphered in this study a biological mechanism that has so far been described only empirically by medicine, potentially explaining intestinal pain and visceral spasms upon food poisoning.
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Affiliation(s)
| | - Rouba Jneid
- Université Côte d'Azur, CNRS, INRA, ISA, France
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese University, Tripoli, Lebanon
| | | | | | | | - Dani Osman
- Faculty of Sciences III and Azm Center for Research in Biotechnology and its Applications, LBA3B, EDST, Lebanese University, Tripoli, Lebanon
| | - Armel Gallet
- Université Côte d'Azur, CNRS, INRA, ISA, France
- * E-mail:
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16
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Méric G, Mageiros L, Pascoe B, Woodcock DJ, Mourkas E, Lamble S, Bowden R, Jolley KA, Raymond B, Sheppard SK. Lineage-specific plasmid acquisition and the evolution of specialized pathogens in Bacillus thuringiensis and the Bacillus cereus group. Mol Ecol 2018; 27:1524-1540. [PMID: 29509989 PMCID: PMC5947300 DOI: 10.1111/mec.14546] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 02/06/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Bacterial plasmids can vary from small selfish genetic elements to large autonomous replicons that constitute a significant proportion of total cellular DNA. By conferring novel function to the cell, plasmids may facilitate evolution but their mobility may be opposed by co-evolutionary relationships with chromosomes or encouraged via the infectious sharing of genes encoding public goods. Here, we explore these hypotheses through large-scale examination of the association between plasmids and chromosomal DNA in the phenotypically diverse Bacillus cereus group. This complex group is rich in plasmids, many of which encode essential virulence factors (Cry toxins) that are known public goods. We characterized population genomic structure, gene content and plasmid distribution to investigate the role of mobile elements in diversification. We analysed coding sequence within the core and accessory genome of 190 B. cereus group isolates, including 23 novel sequences and genes from 410 reference plasmid genomes. While cry genes were widely distributed, those with invertebrate toxicity were predominantly associated with one sequence cluster (clade 2) and phenotypically defined Bacillus thuringiensis. Cry toxin plasmids in clade 2 showed evidence of recent horizontal transfer and variable gene content, a pattern of plasmid segregation consistent with transfer during infectious cooperation. Nevertheless, comparison between clades suggests that co-evolutionary interactions may drive association between plasmids and chromosomes and limit wider transfer of key virulence traits. Proliferation of successful plasmid and chromosome combinations is a feature of specialized pathogens with characteristic niches (Bacillus anthracis, B. thuringiensis) and has occurred multiple times in the B. cereus group.
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Affiliation(s)
- Guillaume Méric
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
| | | | - Ben Pascoe
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
- MRC CLIMB ConsortiumUniversity of BathBathUK
| | - Dan J. Woodcock
- Mathematics Institute and Zeeman Institute for Systems Biology and Infectious Epidemiology ResearchUniversity of WarwickCoventryUK
| | - Evangelos Mourkas
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
| | - Sarah Lamble
- Wellcome Trust Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Rory Bowden
- Wellcome Trust Centre for Human GeneticsUniversity of OxfordOxfordUK
| | | | - Ben Raymond
- Department of Life SciencesFaculty of Natural SciencesImperial College LondonAscotUK
- Department of BiosciencesUniversity of ExeterExeterUK
| | - Samuel K. Sheppard
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
- MRC CLIMB ConsortiumUniversity of BathBathUK
- Department of ZoologyUniversity of OxfordOxfordUK
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17
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Provorov NA, Onishchuk OP. Microbial Symbionts of Insects: Genetic Organization, Adaptive Role, and Evolution. Microbiology (Reading) 2018. [DOI: 10.1134/s002626171802011x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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18
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Lopes R, Cerdeira L, Tavares GS, Ruiz JC, Blom J, Horácio ECA, Mantovani HC, Queiroz MVD. Genome analysis reveals insights of the endophytic Bacillus toyonensis BAC3151 as a potentially novel agent for biocontrol of plant pathogens. World J Microbiol Biotechnol 2017; 33:185. [DOI: 10.1007/s11274-017-2347-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/19/2017] [Indexed: 02/02/2023]
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19
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Loudhaief R, Brun-Barale A, Benguettat O, Nawrot-Esposito MP, Pauron D, Amichot M, Gallet A. Apoptosis restores cellular density by eliminating a physiologically or genetically induced excess of enterocytes in the Drosophila midgut. Development 2017; 144:808-819. [PMID: 28246211 DOI: 10.1242/dev.142539] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/10/2017] [Indexed: 11/20/2022]
Abstract
Using pathogens or high levels of opportunistic bacteria to damage the gut, studies in Drosophila have identified many signaling pathways involved in gut regeneration. Dying cells emit signaling molecules that accelerate intestinal stem cell proliferation and progenitor differentiation to replace the dying cells quickly. This process has been named 'regenerative cell death'. Here, mimicking environmental conditions, we show that the ingestion of low levels of opportunistic bacteria was sufficient to launch an accelerated cellular renewal program despite the brief passage of bacteria in the gut and the absence of cell death and this is is due to the moderate induction of the JNK pathway that stimulates stem cell proliferation. Consequently, the addition of new differentiated cells to the gut epithelium, without preceding cell loss, leads to enterocyte overcrowding. Finally, we show that a couple of days later, the correct density of enterocytes is promptly restored by means of a wave of apoptosis involving Hippo signaling and preferential removal of old enterocytes.
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Affiliation(s)
- Rihab Loudhaief
- Université Côte d'Azur, INRA, CNRS, ISA, 06900 Sophia Antipolis, France
| | | | - Olivia Benguettat
- Université Côte d'Azur, INRA, CNRS, ISA, 06900 Sophia Antipolis, France
| | | | - David Pauron
- Université Côte d'Azur, INRA, CNRS, ISA, 06900 Sophia Antipolis, France
| | - Marcel Amichot
- Université Côte d'Azur, INRA, CNRS, ISA, 06900 Sophia Antipolis, France
| | - Armel Gallet
- Université Côte d'Azur, INRA, CNRS, ISA, 06900 Sophia Antipolis, France
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20
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Bell JA, Friedman SB. GENETIC STRUCTURE AND DIVERSITY WITHIN LOCAL POPULATIONS OF
BACILLUS MYCOIDES. Evolution 2017; 48:1698-1714. [DOI: 10.1111/j.1558-5646.1994.tb02206.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/1992] [Accepted: 03/18/1994] [Indexed: 12/01/2022]
Affiliation(s)
- Julia A. Bell
- Department of Biological Sciences Western Michigan University Kalamazoo Michigan 49008
- Center for Microbial Ecology, Michigan State University East Lansing Michigan 48824
| | - Stephen B. Friedman
- Department of Biological Sciences Western Michigan University Kalamazoo Michigan 49008
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21
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Makart L, Commans F, Gillis A, Mahillon J. Horizontal transfer of chromosomal markers mediated by the large conjugative plasmid pXO16 from Bacillus thuringiensis serovar israelensis. Plasmid 2017; 91:76-81. [DOI: 10.1016/j.plasmid.2017.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/13/2017] [Accepted: 04/16/2017] [Indexed: 01/25/2023]
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22
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Hollensteiner J, Wemheuer F, Harting R, Kolarzyk AM, Diaz Valerio SM, Poehlein A, Brzuszkiewicz EB, Nesemann K, Braus-Stromeyer SA, Braus GH, Daniel R, Liesegang H. Bacillus thuringiensis and Bacillus weihenstephanensis Inhibit the Growth of Phytopathogenic Verticillium Species. Front Microbiol 2017; 7:2171. [PMID: 28149292 PMCID: PMC5241308 DOI: 10.3389/fmicb.2016.02171] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/23/2016] [Indexed: 12/14/2022] Open
Abstract
Verticillium wilt causes severe yield losses in a broad range of economically important crops worldwide. As many soil fumigants have a severe environmental impact, new biocontrol strategies are needed. Members of the genus Bacillus are known as plant growth-promoting bacteria (PGPB) as well as biocontrol agents of pests and diseases. In this study, we isolated 267 Bacillus strains from root-associated soil of field-grown tomato plants. We evaluated the antifungal potential of 20 phenotypically diverse strains according to their antagonistic activity against the two phytopathogenic fungi Verticillium dahliae and Verticillium longisporum. In addition, the 20 strains were sequenced and phylogenetically characterized by multi-locus sequence typing (MLST) resulting in 7 different Bacillus thuringiensis and 13 Bacillus weihenstephanensis strains. All B. thuringiensis isolates inhibited in vitro the tomato pathogen V. dahliae JR2, but had only low efficacy against the tomato-foreign pathogen V. longisporum 43. All B. weihenstephanensis isolates exhibited no fungicidal activity whereas three B. weihenstephanensis isolates showed antagonistic effects on both phytopathogens. These strains had a rhizoid colony morphology, which has not been described for B. weihenstephanensis strains previously. Genome analysis of all isolates revealed putative genes encoding fungicidal substances and resulted in identification of 304 secondary metabolite gene clusters including 101 non-ribosomal polypeptide synthetases and 203 ribosomal-synthesized and post-translationally modified peptides. All genomes encoded genes for the synthesis of the antifungal siderophore bacillibactin. In the genome of one B. thuringiensis strain, a gene cluster for zwittermicin A was detected. Isolates which either exhibited an inhibitory or an interfering effect on the growth of the phytopathogens carried one or two genes encoding putative mycolitic chitinases, which might contribute to antifungal activities. This indicates that chitinases contribute to antifungal activities. The present study identified B. thuringiensis isolates from tomato roots which exhibited in vitro antifungal activity against Verticillium species.
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Affiliation(s)
- Jacqueline Hollensteiner
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Franziska Wemheuer
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Rebekka Harting
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences, Georg-August-University Gottingen, Germany
| | - Anna M Kolarzyk
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences, Georg-August-University Gottingen, Germany
| | - Stefani M Diaz Valerio
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Anja Poehlein
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Elzbieta B Brzuszkiewicz
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Kai Nesemann
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences, Georg-August-University Gottingen, Germany
| | - Susanna A Braus-Stromeyer
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences, Georg-August-University Gottingen, Germany
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Göttingen Center for Molecular Biosciences, Georg-August-University Gottingen, Germany
| | - Rolf Daniel
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
| | - Heiko Liesegang
- Göttingen Genomics Laboratory, Department of Genomic and Applied Microbiology, Institute of Microbiology and Genetics, Georg-August-University Gottingen, Germany
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23
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Genetic diversity and functional characterization of endophytic Bacillus thuringiensis isolates from the North Western Indian Himalayas. ANN MICROBIOL 2016. [DOI: 10.1007/s13213-016-1244-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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24
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Renzi MT, Amichot M, Pauron D, Tchamitchian S, Brunet JL, Kretzschmar A, Maini S, Belzunces LP. Chronic toxicity and physiological changes induced in the honey bee by the exposure to fipronil and Bacillus thuringiensis spores alone or combined. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 127:205-13. [PMID: 26866756 DOI: 10.1016/j.ecoenv.2016.01.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 12/24/2015] [Accepted: 01/28/2016] [Indexed: 05/22/2023]
Abstract
In the agricultural environment, honey bees may be exposed to combinations of pesticides. Until now, the effects of these combinations on honey bee health have been poorly investigated. In this study, we assessed the impacts of biological and chemical insecticides, combining low dietary concentrations of Bacillus thuringiensis (Bt) spores (100 and 1000µg/L) with the chemical insecticide fipronil (1µg/L). In order to assess the possible effects of Cry toxins, the Bt kurstaki strain (Btk) was compared with a Bt strain devoid of toxin-encoding plasmids (Bt Cry(-)). The oral exposure to fipronil and Bt spores from both strains for 10 days did not elicit significant effects on the feeding behavior and survival after 25 days. Local and systemic physiological effects were investigated by measuring the activities of enzymes involved in the intermediary and detoxication metabolisms at two sampling dates (day 10 and day 20). Attention was focused on head and midgut glutathione-S-transferase (GST), midgut alkaline phosphatase (ALP), abdomen glyceraldehyde-3-phosphate dehydrogenase (GAPD) and glucose-6-phosphate dehydrogenase (G6PD). We found that Bt Cry(-) and Btk spores induced physiological modifications by differentially modulating enzyme activities. Fipronil influenced the enzyme activities differently at days 10 and 20 and, when combined with Bt spores, elicited modulations of some spore-induced physiological responses. These results show that an apparent absence of toxicity may hide physiological disruptions that could be potentially damaging for the bees, especially in the case of combined exposures to other environmental stressors.
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Affiliation(s)
- Maria Teresa Renzi
- INRA, Laboratoire de Toxicologie Environnementale, UR 406 A&E, CS 40509, 84914 Avignon Cedex 9, France; Dipartimento di Scienze Agrarie, Università di Bologna, Viale G. Fanin, 42, 40127 Bologna, Italy
| | - Marcel Amichot
- INRA, Université Nice Sophia Antipolis, CNRS, UMR 1355-7254 Institut Sophia Agrobiotech, 06900 Sophia Antipolis, France
| | - David Pauron
- INRA, Université Nice Sophia Antipolis, CNRS, UMR 1355-7254 Institut Sophia Agrobiotech, 06900 Sophia Antipolis, France
| | - Sylvie Tchamitchian
- INRA, Laboratoire de Toxicologie Environnementale, UR 406 A&E, CS 40509, 84914 Avignon Cedex 9, France
| | - Jean-Luc Brunet
- INRA, Laboratoire de Toxicologie Environnementale, UR 406 A&E, CS 40509, 84914 Avignon Cedex 9, France
| | - André Kretzschmar
- INRA, UR Biostatistiques et Processus Spatiaux, CS 40509, 84914 Avignon Cedex 9, France
| | - Stefano Maini
- Dipartimento di Scienze Agrarie, Università di Bologna, Viale G. Fanin, 42, 40127 Bologna, Italy
| | - Luc P Belzunces
- INRA, Laboratoire de Toxicologie Environnementale, UR 406 A&E, CS 40509, 84914 Avignon Cedex 9, France.
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Amichot M, Curty C, Benguettat-Magliano O, Gallet A, Wajnberg E. Side effects of Bacillus thuringiensis var. kurstaki on the hymenopterous parasitic wasp Trichogramma chilonis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3097-3103. [PMID: 26590060 DOI: 10.1007/s11356-015-5830-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/17/2015] [Indexed: 06/05/2023]
Abstract
Most of the detrimental effects of using conventional insecticides to control crop pests are now well identified and are nowadays major arguments for replacing such compounds by the use of biological control agents. In this respect, the bacterium Bacillus thuringiensis var. kurstaki and Trichogramma (Hymenoptera: Trichogrammatidae) parasitic wasp species are both effective against lepidopterous pests and can actually be used concomitantly. In this work, we studied the potential side effects of B. thuringiensis var. kurstaki on Trichogramma chilonis females. We first evidenced an acute toxicity of B. thuringiensis on T. chilonis. Then, after ingestion of B. thuringiensis at sublethal doses, we focused on life history traits of T. chilonis such as longevity, reproductive success and the time spent on host eggs patches. The reproductive success of T. chilonis was not modified by B. thuringiensis while a significant effect was observed on longevity and the time spent on host eggs patches. The physiological and ecological meanings of the results obtained are discussed.
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Affiliation(s)
- Marcel Amichot
- INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900, Sophia Antipolis, France.
| | - Christine Curty
- INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900, Sophia Antipolis, France
| | - Olivia Benguettat-Magliano
- INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900, Sophia Antipolis, France
| | - Armel Gallet
- INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900, Sophia Antipolis, France
| | - Eric Wajnberg
- INRA, Univ. Nice Sophia Antipolis, CNRS, UMR 1355-7254, Institut Sophia Agrobiotech, 06900, Sophia Antipolis, France.
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Massive horizontal gene transfer, strictly vertical inheritance and ancient duplications differentially shape the evolution of Bacillus cereus enterotoxin operons hbl, cytK and nhe. BMC Evol Biol 2015; 15:246. [PMID: 26555390 PMCID: PMC4641410 DOI: 10.1186/s12862-015-0529-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/30/2015] [Indexed: 11/10/2022] Open
Abstract
Background Bacillus cereus sensu lato comprises eight closely related species including the human pathogens Bacillus anthracis and Bacillus cereus. Within B. cereus sensu lato, chromosomally and plasmid-encoded toxins exist. While plasmid-mediated horizontal gene transfer of the emetic toxin, anthrax and insecticidal toxins is known, evolution of enterotoxin genes within the group has not been studied. Results We report draft genome assemblies of 25 strains, a phylogenetic network of 142 strains based on ANI derived from genome sequences and a phylogeny based on whole-genome SNP analysis. The data clearly support subdivision of B. cereus sensu lato into seven phylogenetic groups. While group I, V and VII represent B. pseudomycoides, B. toyonensis and B. cytotoxicus, which are distinguishable at species level (ANI border ≥ 96 %), strains ascribed to the other five species do not match phylogenic groups. The chromosomal enterotoxin operons nheABC and hblCDAB are abundant within B. cereus both isolated from infections and from the environment. While the duplicated hbl variant hbla is present in 22 % of all strains investigated, duplication of nheABC is extremely rare (0.02 %) and appears to be phylogenetically unstable. Distribution of toxin genes was matched to a master tree based on seven concatenated housekeeping genes, which depicts species relationships in B. cereus sensu lato as accurately as whole-genome comparisons. Comparison to the phylogeny of enterotoxin genes uncovered ample evidence for horizontal transfer of hbl, cytK and plcR, as well as frequent deletion of both toxins and duplication of hbl. No evidence for nhe deletion was found and stable horizontal transfer of nhe is rare. Therefore, evolution of B. cereus enterotoxin operons is shaped unexpectedly different for yet unknown reasons. Conclusions Frequent exchange of the pathogenicity factors hbl, cytK and plcR in B. cereus sensu lato appears to be an important mechanism of B. cereus virulence evolution, including so-called probiotic or non-pathogenic species, which might have consequences for risk assessment procedures. In contrast, exclusively vertical inheritance of nhe was observed, and since nhe-negative strains appear to be extremely rare, we suggest that fitness loss may be associated with deletion or horizontal transfer of the nhe operon. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0529-4) contains supplementary material, which is available to authorized users.
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Evidence of two mechanisms involved in Bacillus thuringiensis israelensis decreased toxicity against mosquito larvae: Genome dynamic and toxins stability. Microbiol Res 2015; 176:48-54. [DOI: 10.1016/j.micres.2015.04.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 04/07/2015] [Accepted: 04/17/2015] [Indexed: 11/23/2022]
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Mi X, Ji X, Yang J, Liang L, Si H, Wu J, Zhang N, Wang D. Transgenic potato plants expressing cry3A gene confer resistance to Colorado potato beetle. C R Biol 2015; 338:443-50. [PMID: 26025753 DOI: 10.1016/j.crvi.2015.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/19/2015] [Accepted: 04/20/2015] [Indexed: 12/13/2022]
Abstract
The Colorado potato beetle (Leptinotarsa decemlineata Say, CPB) is a fatal pest, which is a quarantine pest in China. The CPB has now invaded the Xinjiang Uygur Autonomous Region and is constantly spreading eastward in China. In this study, we developed transgenic potato plants expressing cry3A gene. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that the cry3A gene expressed in leaves, stems and roots of the transgenic plants under the control of CaMV 35S promoter, while they expressed only in leaves and stems under the control of potato leaf and stem-specific promoter ST-LS1. The mortality of the larvae was higher (28% and 36%) on the transgenic plant line 35S1 on the 3rd and 4th days, and on ST3 (48%) on the 5th day after inoculation with instar larvae. Insect biomass accumulation on the foliage of the transgenic plant lines 35S1, 35S2 and ST3 was significantly lower (0.42%, 0.43% and 0.42%). Foliage consumption was lowest on transgenic lines 35S8 and ST2 among all plant foliage (7.47 mg/larvae/day and 12.46 mg/larvae/day). The different transgenic plant foliages had varied inhibition to larval growth. The survivors on the transgenic lines obviously were smaller than their original size and extremely weak. The transgenic potato plants with CPB resistance could be used to develop germplasms or varieties for controlling CPB damage and halting its spread in China.
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Affiliation(s)
- Xiaoxiao Mi
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
| | - Xiangzhuo Ji
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
| | - Jiangwei Yang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
| | - Lina Liang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
| | - Huaijun Si
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China
| | - Jiahe Wu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Ning Zhang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China; College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China.
| | - Di Wang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement, Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, China
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Chromosome-Directed PCR-Based Detection and Quantification of Bacillus cereus Group Members with Focus on B. thuringiensis Serovar israelensis Active against Nematoceran Larvae. Appl Environ Microbiol 2015; 81:4894-903. [PMID: 25979887 DOI: 10.1128/aem.00671-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/06/2015] [Indexed: 11/20/2022] Open
Abstract
Bacillus thuringiensis serovar israelensis is a wide-spread soil bacterium affiliated with the B. cereus group (Bcg) and is widely used in biocontrol products applied against mosquito and black fly larvae. For monitoring and quantification of applied B. thuringiensis serovar israelensis and its effect on indigenous B. thuringiensis serovar israelensis and Bcg assemblages, efficient and reliable tools are essential. The abundance and properties of B. thuringiensis serovar israelensis strains in the environment traditionally have been investigated with cultivation-dependent techniques, which are hampered by low sensitivity and the morphological similarity between B. cereus and B. thuringiensis. Currently available PCR-based detection and quantification tools target markers located on plasmids. In this study, a new cultivation-independent PCR-based method for efficient and specific quantification of B. thuringiensis serovar israelensis and Bcg is presented, utilizing two sets of PCR primers targeting the bacterial chromosome. Sequence database searches and empirical tests performed on target and nontarget species, as well as on bulk soil DNA samples, demonstrated that this diagnostic tool is specific for B. thuringiensis serovar israelensis and Bcg. The method will be useful for comparisons of Bcg and B. thuringiensis serovar israelensis abundances in the same samples. Moreover, the effect of B. thuringiensis serovar israelensis-based insecticide application on the total Bcg assemblages, including indigenous populations, can be investigated. This type of information is valuable in risk assessment and policy making for use of B. thuringiensis serovar israelensis in the environment.
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Makart L, Gillis A, Mahillon J. pXO16 from Bacillus thuringiensis serovar israelensis: Almost 350 kb of terra incognita. Plasmid 2015; 80:8-15. [PMID: 25770691 DOI: 10.1016/j.plasmid.2015.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/21/2015] [Accepted: 03/03/2015] [Indexed: 11/20/2022]
Abstract
Bacillus thuringiensis strains usually harbor large sets of plasmids, some of which carrying the entomopathogenic δ-endotoxins. B. thuringiensis serovar israelensis, active on Dipteran larvae, carries the very large conjugative plasmid pXO16 (350 kb). pXO16 displays a macroscopic aggregation phenotype when liquid cultures of conjugative partners are mixed. Its conjugative apparatus is able of transferring itself and other non-conjugative and non-mobilizable plasmids in a fast and very efficient manner. Even though its conjugative kinetics and capabilities have been extensively studied, the genetic bases for this unique transfer system remain largely unknown. In this work, the sequence of pXO16 has been identified in the existing sequenced genome of B. thuringiensis sv. israelensis HD-789 as corresponding to the p01 plasmid. Despite pXO16 sequence being highly coding, few CDS possess homologs in the databases. However, potential regions responsible for the aggregation phenotype and the plasmid replication have been highlighted. The common orientation of all CDS and the presence of a high number of potential paralogs suggested a phage-like nature. Concerning conjugative functions, no significant type IV secretion system homologs have been found, indicating that pXO16 encodes an unforeseen conjugative system.
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Affiliation(s)
- Lionel Makart
- Laboratory of Food and Environmental Microbiology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Annika Gillis
- Laboratory of Food and Environmental Microbiology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium
| | - Jacques Mahillon
- Laboratory of Food and Environmental Microbiology, Université Catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
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Palma L, Muñoz D, Berry C, Murillo J, Caballero P. Bacillus thuringiensis toxins: an overview of their biocidal activity. Toxins (Basel) 2014; 6:3296-325. [PMID: 25514092 PMCID: PMC4280536 DOI: 10.3390/toxins6123296] [Citation(s) in RCA: 349] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/07/2014] [Accepted: 12/03/2014] [Indexed: 11/16/2022] Open
Abstract
Bacillus thuringiensis (Bt) is a Gram positive, spore-forming bacterium that synthesizes parasporal crystalline inclusions containing Cry and Cyt proteins, some of which are toxic against a wide range of insect orders, nematodes and human-cancer cells. These toxins have been successfully used as bioinsecticides against caterpillars, beetles, and flies, including mosquitoes and blackflies. Bt also synthesizes insecticidal proteins during the vegetative growth phase, which are subsequently secreted into the growth medium. These proteins are commonly known as vegetative insecticidal proteins (Vips) and hold insecticidal activity against lepidopteran, coleopteran and some homopteran pests. A less well characterized secretory protein with no amino acid similarity to Vip proteins has shown insecticidal activity against coleopteran pests and is termed Sip (secreted insecticidal protein). Bin-like and ETX_MTX2-family proteins (Pfam PF03318), which share amino acid similarities with mosquitocidal binary (Bin) and Mtx2 toxins, respectively, from Lysinibacillus sphaericus, are also produced by some Bt strains. In addition, vast numbers of Bt isolates naturally present in the soil and the phylloplane also synthesize crystal proteins whose biological activity is still unknown. In this review, we provide an updated overview of the known active Bt toxins to date and discuss their activities.
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Affiliation(s)
- Leopoldo Palma
- Instituto de Agrobiotecnología, CSIC-UPNA-Gobierno de Navarra, Campus Arrosadía, Mutilva Baja, 31192 Navarra, Spain.
| | - Delia Muñoz
- Grupo de Protección Cultivos, Departamento de Producción Agraria, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública de Navarra, Pamplona, 31006 Navarra, Spain.
| | - Colin Berry
- Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3AT, UK.
| | - Jesús Murillo
- Grupo de Protección Cultivos, Departamento de Producción Agraria, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad Pública de Navarra, Pamplona, 31006 Navarra, Spain.
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, CSIC-UPNA-Gobierno de Navarra, Campus Arrosadía, Mutilva Baja, 31192 Navarra, Spain.
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Abstract
Plasmid-encoded virulence factors are important in the pathogenesis of diseases caused by spore-forming bacteria. Unlike many other bacteria, the most common virulence factors encoded by plasmids in Clostridium and Bacillus species are protein toxins. Clostridium perfringens causes several histotoxic and enterotoxin diseases in both humans and animals and produces a broad range of toxins, including many pore-forming toxins such as C. perfringens enterotoxin, epsilon-toxin, beta-toxin, and NetB. Genetic studies have led to the determination of the role of these toxins in disease pathogenesis. The genes for these toxins are generally carried on large conjugative plasmids that have common core replication, maintenance, and conjugation regions. There is considerable functional information available about the unique tcp conjugation locus carried by these plasmids, but less is known about plasmid maintenance. The latter is intriguing because many C. perfringens isolates stably maintain up to four different, but closely related, toxin plasmids. Toxin genes may also be plasmid-encoded in the neurotoxic clostridia. The tetanus toxin gene is located on a plasmid in Clostridium tetani, but the botulinum toxin genes may be chromosomal, plasmid-determined, or located on bacteriophages in Clostridium botulinum. In Bacillus anthracis it is well established that virulence is plasmid determined, with anthrax toxin genes located on pXO1 and capsule genes on a separate plasmid, pXO2. Orthologs of these plasmids are also found in other members of the Bacillus cereus group such as B. cereus and Bacillus thuringiensis. In B. thuringiensis these plasmids may carry genes encoding one or more insecticidal toxins.
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Bishop AH, Robinson CV. Bacillus thuringiensis HD-1 Cry- : development of a safe, non-insecticidal simulant for Bacillus anthracis. J Appl Microbiol 2014; 117:654-62. [PMID: 24903218 DOI: 10.1111/jam.12560] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 05/28/2014] [Accepted: 05/31/2014] [Indexed: 11/26/2022]
Abstract
AIMS A representative simulant for spores of Bacillus anthracis is needed for field testing. Bacillus thuringiensis is gaining recognition as a suitable organism. A strain that does not form the insecticidal, parasporal crystals that are characteristic of this species is a more accurate physical representative of B. anthracis spores. We developed noninsecticidal derivatives of two isolates of B. thuringiensis HD-1. METHODS AND RESULTS Two plasmid-cured derivatives of B. thuringiensis HD-1, unable to make crystal toxins ('Cry(-) '), were isolated. These isolates and the existing Cry(-) strain, B. thuringiensis Al Hakam, were probed with PCR assays against the known insecticidal genes cry, vip and cyt. Their genomic DNA was sequenced to demonstrate a lack of insecticidal genes. This was confirmed by bioassays against a number of invertebrate species. Real-time PCR assays were developed to identify the B. thuringiensis HD-1 Cry(-) derivatives and an effective differential and selective medium was assessed. CONCLUSIONS All three Cry(-) isolates are devoid of known insecticidal determinants. The B. thuringiensis HD-1 Cry(-) derivatives can easily be recovered from soil and identified by PCR with some selectivity. SIGNIFICANCE AND IMPACT OF THE STUDY The B. thuringiensis HD-1 Cry(-) derivatives represent accurate, nongenetically manipulated simulants for B. anthracis with excellent human and environmental safety records.
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Affiliation(s)
- A H Bishop
- Detection Department, Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK
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34
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Advances in Microbial Insect Control in Horticultural Ecosystem. SUSTAINABLE DEVELOPMENT AND BIODIVERSITY 2014. [DOI: 10.1007/978-3-319-06904-3_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Minard G, Mavingui P, Moro CV. Diversity and function of bacterial microbiota in the mosquito holobiont. Parasit Vectors 2013; 6:146. [PMID: 23688194 PMCID: PMC3667145 DOI: 10.1186/1756-3305-6-146] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/08/2013] [Indexed: 11/15/2022] Open
Abstract
Mosquitoes (Diptera: Culicidae) have been shown to host diverse bacterial communities that vary depending on the sex of the mosquito, the developmental stage, and ecological factors. Some studies have suggested a potential role of microbiota in the nutritional, developmental and reproductive biology of mosquitoes. Here, we present a review of the diversity and functions of mosquito-associated bacteria across multiple variation factors, emphasizing recent findings. Mosquito microbiota is considered in the context of possible extended phenotypes conferred on the insect hosts that allow niche diversification and rapid adaptive evolution in other insects. These kinds of observations have prompted the recent development of new mosquito control methods based on the use of symbiotically-modified mosquitoes to interfere with pathogen transmission or reduce the host life span and reproduction. New opportunities for exploiting bacterial function for vector control are highlighted.
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Affiliation(s)
- Guillaume Minard
- UMR CNRS 5557, USC INRA 1364, VetAgro Sup, Ecologie Microbienne, FR41 BioEnvironment and Health, Université de Lyon 1, Villeurbanne F-69622, France
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36
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Soufiane B, Baizet M, Côté JC. Multilocus sequence analysis of Bacillus thuringiensis serovars navarrensis, bolivia and vazensis and Bacillus weihenstephanensis reveals a common phylogeny. Antonie van Leeuwenhoek 2012; 103:195-205. [PMID: 23073664 DOI: 10.1007/s10482-012-9800-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/16/2012] [Indexed: 11/28/2022]
Abstract
The Bacillus cereus group sensu lato includes six closely-related bacterial species: Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Bacillus mycoides, Bacillus pseudomycoides and Bacillus weihenstephanensis. B. thuringiensis is distinguished from the other species mainly by the appearance of an inclusion body upon sporulation. B. weihenstephanensis is distinguished based on its psychrotolerance and the presence of specific signature sequences in the 16S rRNA gene and cspA genes. A total of seven housekeeping genes (glpF, gmK, ilvD, pta, purH, pycA and tpi) from different B. thuringiensis serovars and B. weihenstephanensis strains were amplified and their nucleotide sequences determined. A maximum likelihood phylogenetic tree was inferred from comparisons of the concatenated sequences. B. thuringiensis serovars navarrensis, bolivia and vazensis clustered not with the other B. thuringiensis serovars but rather with the B. weihenstephanensis strains, indicative of a common phylogeny. In addition, specific signature sequences and single nucleotide polymorphisms common to B. thuringiensis serovars navarrensis, bolivia and vazensis and the B. weihenstephanensis strains, and absent in the other B. thuringiensis serovars, were identified.
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Affiliation(s)
- Brahim Soufiane
- Agriculture and Agri-Food Canada, Research Centre, 430 Gouin Blvd, Saint-Jean-sur-Richelieu, QC, J3B 3E6, Canada
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Raymond B, West SA, Griffin AS, Bonsall MB. The dynamics of cooperative bacterial virulence in the field. Science 2012; 337:85-8. [PMID: 22767928 DOI: 10.1126/science.1218196] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Laboratory experiments have shown that the fitness of microorganisms can depend on cooperation between cells. Although this insight has revolutionized our understanding of microbial life, results from artificial microcosms have not been validated in complex natural populations. We investigated the sociality of essential virulence factors (crystal toxins) in the pathogen Bacillus thuringiensis using diamondback moth larvae (Plutella xylostella) as hosts. We show that toxin production is cooperative, and in a manipulative field experiment, we observed persistent high relatedness and frequency- and density-dependent selection, which favor stable cooperation. Conditions favoring social virulence can therefore persist in the face of natural population processes, and social interactions (rapid cheat invasion) may account for the rarity of natural disease outbreaks caused by B. thuringiensis.
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Affiliation(s)
- Ben Raymond
- School of Biological Sciences, Royal Holloway University of London, Egham, UK.
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Cliff JB, Kreuzer HW, Ehrhardt CJ, Wunschel DS. The Microbe: The Basics of Structure, Morphology, and Physiology as They Relate to Microbial Characterization and Attribution. CHEMICAL AND PHYSICAL SIGNATURES FOR MICROBIAL FORENSICS 2012. [PMCID: PMC7123343 DOI: 10.1007/978-1-60327-219-3_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This chapter is meant to (1) review classical methods used to characterize and classify microbes and (2) introduce new molecular methods used in microbial characterization. The fundamental composition of microbes is discussed as well as their importance in classification of microbes into genus and species. Classical microbiological methods in general seek to define the common features of specific bacterial groups as a means of classification and identification of microbes. Thus, the focus was to describe the common features which discriminated closely related groups of organisms. In contrast, the newer molecular methods often seek to expand the classification of microbes not only as a means to organize microbial phylogeny but also to differentiate signatures between microbes identified within a species in greater detail. Molecular biology tools are used both as an adjunct to established methods and as replacement for classical methods for detection, discrimination, or identification of bacterial and viral species.
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Affiliation(s)
- John B. Cliff
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, 6009 West Australia Australia
| | - Helen W. Kreuzer
- Chemical and Biological Signature Scienc, Pacific Northwest National Laboratory, PO Box 999, MS P7-50, Richland, 99352 Washington USA
| | - Christopher J. Ehrhardt
- Department of Forensic Science, Virginia Commonwealth University, 1020 W. Main Street, Richmond, 23284 Virginia USA
| | - David S. Wunschel
- Chemical and Biological Signature Scienc, Pacific Northwest National Laboratory, PO Box 999, MS P7-50, Richland, 99352 Washington USA
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Fang Y, Li Z, Liu J, Shu C, Wang X, Zhang X, Yu X, Zhao D, Liu G, Hu S, Zhang J, Al-Mssallem I, Yu J. A pangenomic study of Bacillus thuringiensis. J Genet Genomics 2011; 38:567-76. [PMID: 22196399 DOI: 10.1016/j.jgg.2011.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Revised: 10/25/2011] [Accepted: 11/09/2011] [Indexed: 11/28/2022]
Abstract
Bacillus thuringiensis (B. thuringiensis) is a soil-dwelling Gram-positive bacterium and its plasmid-encoded toxins (Cry) are commonly used as biological alternatives to pesticides. In a pangenomic study, we sequenced seven B. thuringiensis isolates in both high coverage and base-quality using the next-generation sequencing platform. The B. thuringiensis pangenome was extrapolated to have 4196 core genes and an asymptotic value of 558 unique genes when a new genome is added. Compared to the pangenomes of its closely related species of the same genus, B. thuringiensis pangenome shows an open characteristic, similar to B. cereus but not to B. anthracis; the latter has a closed pangenome. We also found extensive divergence among the seven B. thuringiensis genome assemblies, which harbor ample repeats and single nucleotide polymorphisms (SNPs). The identities among orthologous genes are greater than 84.5% and the hotspots for the genome variations were discovered in genomic regions of 2.3-2.8Mb and 5.0-5.6Mb. We concluded that high-coverage sequence assemblies from multiple strains, before all the gaps are closed, are very useful for pangenomic studies.
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Affiliation(s)
- Yongjun Fang
- James D. Watson Institute of Genome Sciences, College of Life Science, Zhejiang University, Hangzhou 310058, China
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Sanahuja G, Banakar R, Twyman RM, Capell T, Christou P. Bacillus thuringiensis: a century of research, development and commercial applications. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:283-300. [PMID: 21375687 DOI: 10.1111/j.1467-7652.2011.00595.x] [Citation(s) in RCA: 397] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Bacillus thuringiensis (Bt) is a soil bacterium that forms spores during the stationary phase of its growth cycle. The spores contain crystals, predominantly comprising one or more Cry and/or Cyt proteins (also known as δ-endotoxins) that have potent and specific insecticidal activity. Different strains of Bt produce different types of toxin, each of which affects a narrow taxonomic group of insects. Therefore, Bt toxins have been used as topical pesticides to protect crops, and more recently the proteins have been expressed in transgenic plants to confer inherent pest resistance. Bt transgenic crops have been overwhelmingly successful and beneficial, leading to higher yields and reducing the use of chemical pesticides and fossil fuels. However, their deployment has attracted some criticism particularly with regard to the potential evolution of pest-resistant insect strains. Here, we review recent progress in the development of Bt technology and the countermeasures that have been introduced to prevent the evolution of resistant insect populations.
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Affiliation(s)
- Georgina Sanahuja
- Department of Plant Production and Forestry Science, ETSEA, University of Lleida, Lleida, Spain
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Fondi M, Fani R. The horizontal flow of the plasmid resistome: clues from inter-generic similarity networks. Environ Microbiol 2010; 12:3228-42. [DOI: 10.1111/j.1462-2920.2010.02295.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Liu XY, Ruan LF, Hu ZF, Peng DH, Cao SY, Yu ZN, Liu Y, Zheng JS, Sun M. Genome-wide screening reveals the genetic determinants of an antibiotic insecticide in Bacillus thuringiensis. J Biol Chem 2010; 285:39191-200. [PMID: 20864531 DOI: 10.1074/jbc.m110.148387] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thuringiensin is a thermostable secondary metabolite in Bacillus thuringiensis and has insecticidal activity against a wide range of insects. Until now, the regulatory mechanisms and genetic determinants involved in thuringiensin production have remained unclear. Here, we successfully used heterologous expression-guided screening in an Escherichia coli-Bacillus thuringiensis shuttle bacterial artificial chromosome library, to clone the intact thuringiensin synthesis (thu) cluster. Then the thu cluster was located on a 110-kb endogenous plasmid bearing insecticide crystal protein gene cry1Ba in strain CT-43. Furthermore, the plasmid, named pBMB0558, was indirectly cloned and sequenced. The gene functions on pBMB0558 were annotated by BLAST based on the GenBank(TM) and KEGG databases. The genes on pBMB0558 could be classified into three functional modules: a thuringiensin synthesis cluster, a type IV secretion system-like module, and mobile genetic elements. By HPLC coupling mass spectrometer, atmospheric pressure ionization with ion trap, and TOF technologies, biosynthetic intermediates of thuringiensin were detected. The thuE gene is proved to be responsible for the phosphorylation of thuringiensin at the last step by vivo and vitro activity assays. The thuringiensin biosynthesis pathway was deduced and clarified. We propose that thuringiensin is an adenine nucleoside oligosaccharide rather than an adenine nucleotide analog, as is traditionally believed, based on the predicted functions of the key enzymes, glycosyltransferase (ThuF) and exopolysaccharide polymerization protein (Thu1).
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Affiliation(s)
- Xiao-Yan Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Santos CA, Vilas-Bôas GT, Lereclus D, Suzuki MT, Angelo EA, Arantes OMN. Conjugal transfer between Bacillus thuringiensis and Bacillus cereus strains is not directly correlated with growth of recipient strains. J Invertebr Pathol 2010; 105:171-5. [PMID: 20600090 DOI: 10.1016/j.jip.2010.06.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 06/24/2010] [Accepted: 06/29/2010] [Indexed: 11/26/2022]
Abstract
Bacillus thuringiensis and Bacillus cereus belong to the B. cereus species group. The two species share substantial chromosomal similarity and differ mostly in their plasmid content. The phylogenetic relationship between these species remains a matter of debate. There is genetic exchange both within and between these species, and current evidence indicates that insects are a particularly suitable environment for the growth of and genetic exchange between these species. We investigated the conjugation efficiency of B. thuringiensis var. kurstaki KT0 (pHT73-Em) as a donor and a B. thuringiensis and several B. cereus strains as recipients; we used one-recipient and two-recipient conjugal transfer systems in vitro (broth and filter) and in Bombyx mori larvae, and assessed multiplication following conjugation between Bacillus strains. The B. thuringiensis KT0 strain did not show preference for genetic exchange with the B. thuringiensis recipient strain over that with the B. cereus recipient strains. However, B. thuringiensis strains germinated and multiplied more efficiently than B. cereus strains in insect larvae and only B. thuringiensis maintained complete spore germination for at least 24 h in B. mori larvae. These findings show that there is no positive association between bacterial multiplication efficiency and conjugation ability in infected insects for the used strains.
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Affiliation(s)
- Clelton A Santos
- Departamento de Biologia Geral, CCB, Universidade Estadual de Londrina, CP 6001, 86051-990 Londrina/PR, Brazil
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Molecular and biological characterization of native Bacillus thuringiensis strains for controlling tomato leafminer (Tuta absoluta Meyrick) (Lepidoptera: Gelechiidae) in Colombia. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0493-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Du C, Martin PA, Nickerson KW. Comparison of Disulfide Contents and Solubility at Alkaline pH of Insecticidal and Noninsecticidal Bacillus thuringiensis Protein Crystals. Appl Environ Microbiol 2010; 60:3847-53. [PMID: 16349421 PMCID: PMC201894 DOI: 10.1128/aem.60.10.3847-3853.1994] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared two insecticidal and eight noninsecticidal soil isolates of Bacillus thuringiensis with regard to the solubility of their proteinaceous crystals at alkaline pH values. The protein disulfide contents of the insecticidal and noninsecticidal crystals were equivalent. However, six of the noninsecticidal crystals were soluble only at pH values of >/=12. This lack of solubility contributed to their lack of toxicity. One crystal type which was soluble only at pH >/=12 (strain SHP 1-12) did exhibit significant toxicity to tobacco hornworm larvae when the crystals were presolubilized. In contrast, freshly prepared crystals from the highly insecticidal strain HD-1 were solubilized at pH 9.5 to 10.5, but when these crystals were denatured, by either 8 M urea or autoclave temperatures, they became nontoxic and were soluble only at pH values of >/=12. These changes in toxicity and solubility occurred even though the denatured HD-1 crystals were morphologically indistinguishable from native crystals. Our data are consistent with the view that insecticidal crystals contain distorted, destabilized disulfide bonds which allow them to be solubilized at pH values (9.5 to 10.5) characteristic of lepidopteran and dipteran larval midguts.
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Affiliation(s)
- C Du
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0343
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Höfte H, Van Rie J, Jansens S, Van Houtven A, Vanderbruggen H, Vaeck M. Monoclonal Antibody Analysis and Insecticidal Spectrum of Three Types of Lepidopteran-Specific Insecticidal Crystal Proteins of Bacillus thuringiensis. Appl Environ Microbiol 2010; 54:2010-7. [PMID: 16347711 PMCID: PMC202794 DOI: 10.1128/aem.54.8.2010-2017.1988] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have investigated the protein composition and the insecticidal spectrum of crystals of 29 Bacillus thuringiensis strains active against lepidopteran larvae. All crystals contained proteins of 130 to 140 kilodaltons (kDa) which could be grouped into three types by the molecular weight of the protoxin and the trypsin-activated core fragment. Proteins of the three types showed a characteristic insecticidal spectrum when tested against five lepidopteran species. Type A crystal proteins were protoxins of 130 or 133 kDa, which were processed into 60-kDa toxins by trypsin. Several genes encoding crystal proteins of this type have been cloned and sequenced earlier. They are highly conserved in the N-terminal half of the toxic fragment and were previously classified in three subtypes (the 4.5-, 5.3-, and 6.6-kilobase subtypes) based on the restriction map of their genes. The present study shows that different proteins of these three subtypes were equally toxic against Manduca sexta and Pieris brassicae and had no detectable activity against Spodoptera littoralis. However, the 4.5-, 5.3-, and 6.6-kilobase subtypes differed in their toxicity against Heliothis virescens and Mamestra brassicae. Type B crystal proteins consisted of 140-kDa protoxins with a 55-kDa tryptic core fragment. These were only active against one of the five insect species tested (P. brassicae). The protoxin and the trypsin-activated toxin of type C were 135- and 63-kDa proteins, respectively. Proteins of this type were associated with high toxicity against S. littoralis and M. brassicae. A panel of 35 monoclonal antibodies was used to compare the structural characteristics of crystal proteins of the three different types and subtypes. Each type of protein could be associated with a typical epitope structure, indicating an unambiguous correlation between antigenic structure and insect specificity.
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Affiliation(s)
- H Höfte
- Plant Genetic Systems, N.V., Plateaustraat 22, B-9000 Ghent, Belgium
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Lecadet MM, Chaufaux J, Ribier J, Lereclus D. Construction of Novel Bacillus thuringiensis Strains with Different Insecticidal Activities by Transduction and Transformation. Appl Environ Microbiol 2010; 58:840-9. [PMID: 16348674 PMCID: PMC195343 DOI: 10.1128/aem.58.3.840-849.1992] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The shuttle vector pHT3101 and its derivative pHT408, bearing a copy of a cryIA(a) delta-endotoxin gene, were transferred into several Bacillus thuringiensis subspecies through phage CP-54Ber-mediated transduction, with frequencies ranging from 5 x 10 to 2 x 10 transductant per CFU, depending on the strain and on the plasmid. In Cry and Cry native recipients, the introduction of the cryIA(a) gene resulted in the formation of large bipyramidal crystals that were active against the insect Plutella xylostella (order Lepidoptera). In both cases, high levels of gene expression were observed. Transductants displaying a dual specificity were constructed by using as recipients the new isolates LM63 and LM79, which have larvicidal activity against insects of the order Coleoptera. It was not possible, however, to introduce pHT7911 into B. thuringiensis subsp. entomocidus, aizawai, or israelensis by transduction. However, electrotransformation was successful, and transformants expressing the toxin gene cryIIIA, carried by pHT7911, were obtained. Again, high levels of expression of the cloned gene were observed. The results indicate that CP-54Ber-mediated transduction is a useful procedure for introducing cloned crystal protein genes into various B. thuringiensis recipients and thereby creating strains with new combinations of genes. Finally it was also shown that pHT3101 is a very good expression vector for the cloned delta-endotoxin genes in the different recipients.
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Affiliation(s)
- M M Lecadet
- Unité de Biochimie Microbienne, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris Cedex 15, Station de Recherches de Lutte Biologique, Institut National de la Recherche Agronomique, 78280 Guyancourt, and U.F.R. de Biologie Génétique, Université Paris VII, 75251 Paris Cedex 05, France
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Kolstø AB, Tourasse NJ, Økstad OA. What sets Bacillus anthracis apart from other Bacillus species? Annu Rev Microbiol 2009; 63:451-76. [PMID: 19514852 DOI: 10.1146/annurev.micro.091208.073255] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacillus anthracis is the cause of anthrax, and two large plasmids are essential for toxicity: pXO1, which contains the toxin genes, and pXO2, which encodes a capsule. B. anthracis forms a highly monomorphic lineage within the B. cereus group, but strains of Bacillus thuringiensis and B. cereus exist that are genetically closely related to the B. anthracis cluster. During the past five years B. cereus strains that contain the pXO1 virulence plasmid were discovered, and strains with both pXO1 and pXO2 have been isolated from great apes in Africa. Therefore, the presence of pXO1 and pXO2 no longer principally separates B. anthracis from other Bacilli. The B. anthracis lineage carries a specific mutation in the global regulator PlcR, which controls the transcription of secreted virulence factors in B. cereus and B. thuringiensis. Coevolution of the B. anthracis chromosome with its plasmids may be the basis for the successful development and uniqueness of the B. anthracis lineage.
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Affiliation(s)
- Anne-Brit Kolstø
- Laboratory for Microbial Dynamics and Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo 0316, Norway.
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50
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Hu X, Swiecicka I, Timmery S, Mahillon J. Sympatric soil communities of Bacillus cereus sensu lato: population structure and potential plasmid dynamics of pXO1- and pXO2-like elements. FEMS Microbiol Ecol 2009; 70:344-55. [PMID: 19780824 DOI: 10.1111/j.1574-6941.2009.00771.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Eighty soil-borne Bacillus cereus group isolates were collected from two neighbouring geographical sites in Belgium. Their genetic relationships and population structure were assessed using Multilocus sequence typing analysis of five chromosomal genes, while the contribution of extrachromosomal elements to the population dynamics was gauged by the presence, diversity and transfer capacity of pXO1- and pXO2-like plasmids. Globally, the bacterial population displayed a broad diversity, including an important subpopulation of psychrotolerant isolates related to Bacillus weihenstephanensis. pXO1- and pXO2-like replicons were present in 12% and 21% of the isolates, but no Bacillus anthracis-related toxin genes were found. Furthermore, only one of the isolates containing a pXO2-related plasmid was shown to be able to mobilize small non-self-conjugative plasmids. Interestingly, several B. cereus sensu lato isolates displaying the same sequence type were observed to have different plasmid contents, suggesting the occurrence of horizontal gene exchange. Similarly, a number of pXO2-like replicons with identical sequences were found in distinct bacterial isolates, therefore strongly arguing for lateral transfers among sympatric bacteria.
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Affiliation(s)
- Xiaomin Hu
- Laboratory of Food and Environmental Microbiology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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