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Kang X, Zhou X, Tang Y, Jiang Z, Chen J, Mohsin M, Yue M. Characterization of Two-Component System CitB Family in Salmonella Pullorum. Int J Mol Sci 2022; 23:ijms231710201. [PMID: 36077599 PMCID: PMC9456408 DOI: 10.3390/ijms231710201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Salmonella enterica, serovar Gallinarum, biovar Pullorum, is an avian-specific pathogen which has caused considerable economic losses to the poultry industry worldwide. Two-component systems (TCSs) play an essential role in obtaining nutrients, detecting the presence of neighboring bacteria and regulating the expression of virulence factors. The genome analysis of S. Pullorum strain S06004 suggesting the carriage of 22 pairs of TCSs, which belong to five families named CitB, OmpR, NarL, Chemotaxis and LuxR. In the CitB family, three pairs of TCSs, namely CitA-CitB, DcuS-DcuR and DpiB-DpiA, remain unaddressed in S. Pullorum. To systematically investigate the function of the CitB family in S. Pullorum, four mutants, ΔcitAB (abbreviated as Δcit), ΔdcuSR (Δdcu), ΔdpiBA (Δdpi) and ΔcitABΔdcuSRΔdpiBA (Δ3), were made using the CRISPR/Cas9 system. The results demonstrated that the CitB family did not affect the growth of bacteria, the results of biochemical tests, invasion and proliferation in chicken macrophage HD-11 cells and the expression of fimbrial protein. But the mutants showed thicker biofilm formation, higher resistance to antimicrobial agents, enhanced tolerance to inhibition by egg albumen and increased virulence in chicken embryos. Moreover, the deletion of Dpi TCS was detrimental to survival after exposure to hyperosmotic and oxidative environments, as well as the long-term colonization of the small intestine of chickens. Collectively, we provided new knowledge regarding the possible role of the CitB family involved in the pathogenic processes of S. Pullorum.
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Affiliation(s)
- Xiamei Kang
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Xiao Zhou
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Yanting Tang
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Zhijie Jiang
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Jiaqi Chen
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Muhammad Mohsin
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
| | - Min Yue
- Institute of Preventive Veterinary Sciences, Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou 310058, China
- Hainan Institute, Zhejiang University, Sanya 572025, China
- Zhejiang Provincial Key Laboratory, Preventive Veterinary Medicine, Hangzhou 310058, China
- Correspondence: ; Tel./Fax: +86-571-88982832
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orf20 in prophage phiv142-3 contributes to the adhesion and colonization ability of avian pathogenic Escherichia coli strain DE142 by affecting the formation of flagella and I fimbriae. Vet Microbiol 2019; 235:301-309. [PMID: 31383317 DOI: 10.1016/j.vetmic.2019.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/17/2019] [Accepted: 07/20/2019] [Indexed: 12/21/2022]
Abstract
We have previously demonstrated that prophage phiv142-3 enhances the colonization ability of avian pathogenic Escherichia coli (APEC) strain DE142. However, the mechanism of this action remains unknown. In this study, we demonstrate that deletion of phiv142-3 orf20 leads to a decrease in the survival ability in chicken serum, adhesion, and ability to invade DF-1 cells of mutant strain DE142Δorf20 compared with that of wild type (WT). Avian infection assays showed that bacterial loads in lungs and hearts of chickens challenged with the mutant are decreased to 7% and 8.3% compared with those challenged with the WT. The number of flagella and I fimbriae of the mutant are decreased and the mutant exhibits filamentation. However, protein ORF20 shows no adhesion ability to DF-1 cells in adherence inhibition experiments, indicating that it does not directly participate in adhesion. qRT-PCR revealed that the deletion of orf20 leads to reduction in the expression of nine genes related to the exportation of flagellar protein and two I-fimbriae-related genes (fimA and fimH), but does not affect genes related to the synthesis of flagella and other adhesins. Compared with the WT, the transcription level of the cell-division-associated genes minC and minD was increased 1.4-fold and 2.5-fold in mutant DE142Δorf20, respectively, indicating that orf20 affects the morphology of DE142 by regulating expression of minC and minD. Thus, our study revealed that orf20 in prophage phiv142-3 played a role in flagellar exportation, cell morphology, and I fimbriae synthesis.
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Kolenda R, Ugorski M, Grzymajlo K. Everything You Always Wanted to Know About Salmonella Type 1 Fimbriae, but Were Afraid to Ask. Front Microbiol 2019; 10:1017. [PMID: 31139165 PMCID: PMC6527747 DOI: 10.3389/fmicb.2019.01017] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/24/2019] [Indexed: 12/19/2022] Open
Abstract
Initial attachment to host intestinal mucosa after oral infection is one of the most important stages during bacterial pathogenesis. Adhesive structures, widely present on the bacterial surface, are mainly responsible for the first contact with host cells and of host-pathogen interactions. Among dozens of different bacterial adhesins, type 1 fimbriae (T1F) are one of the most common adhesive organelles in the members of the Enterobacteriaceae family, including Salmonella spp., and are important virulence factors. Those long, thin structures, composed mainly of FimA proteins, are responsible for recognizing and binding high-mannose oligosaccharides, which are carried by various glycoproteins and expressed at the host cell surface, via FimH adhesin, which is presented at the top of T1F. In this review, we discuss investigations into the functions of T1F, from the earliest work published in 1958 to operon organization, organelle structure, T1F biogenesis, and the various functions of T1F in Salmonella-host interactions. We give special attention to regulation of T1F expression and their role in binding of Salmonella to cells, cell lines, organ explants, and other surfaces with emphasis on biofilm formation and discuss T1F role as virulence factors based on work using animal models. We also discuss the importance of allelic variation in fimH to Salmonella pathogenesis, as well as role of FimH in Salmonella host specificity.
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Affiliation(s)
- Rafal Kolenda
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Maciej Ugorski
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Krzysztof Grzymajlo
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
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Wang KC, Huang CH, Ding SM, Chen CK, Fang HW, Huang MT, Fang SB. Role of yqiC in the Pathogenicity of Salmonella and Innate Immune Responses of Human Intestinal Epithelium. Front Microbiol 2016; 7:1614. [PMID: 27777572 PMCID: PMC5056187 DOI: 10.3389/fmicb.2016.01614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/27/2016] [Indexed: 01/12/2023] Open
Abstract
The yqiC gene of Salmonella enterica serovar Typhimurium (S. Typhimurium) regulates bacterial growth at different temperatures and mice survival after infection. However, the role of yqiC in bacterial colonization and host immunity remains unknown. We infected human LS174T, Caco-2, HeLa, and THP-1 cells with S. Typhimurium wild-type SL1344, its yqiC mutant, and its complemented strain. Bacterial colonization and internalization in the four cell lines significantly reduced on yqiC depletion. Post-infection production of interleukin-8 and human β-defensin-3 in LS174T cells significantly reduced because of yqiC deleted in S. Typhimurium. The phenotype of yqiC mutant exhibited few and short flagella, fimbriae on the cell surface, enhanced biofilm formation, upregulated type-1 fimbriae expression, and reduced bacterial motility. Type-1 fimbriae, flagella, SPI-1, and SPI-2 gene expression was quantified using real-time PCR. The data show that deletion of yqiC upregulated fimA and fimZ expression and downregulated flhD, fliZ, invA, and sseB expression. Furthermore, thin-layer chromatography and high-performance liquid chromatography revealed the absence of menaquinone in the yqiC mutant, thus validating the importance of yqiC in the bacterial electron transport chain. Therefore, YqiC can negatively regulate FimZ for type-1 fimbriae expression and manipulate the functions of its downstream virulence factors including flagella, SPI-1, and SPI-2 effectors.
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Affiliation(s)
- Ke-Chuan Wang
- Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
| | - Chih-Hung Huang
- Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology Taipei, Taiwan
| | - Shih-Min Ding
- Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of TechnologyTaipei, Taiwan
| | - Ching-Kuo Chen
- Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology Taipei, Taiwan
| | - Hsu-Wei Fang
- Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of TechnologyTaipei, Taiwan; Institute of Biomedical Engineering and Nanomedicine - National Health Research InstitutesZhunan, Taiwan
| | - Ming-Te Huang
- Department of Surgery, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Surgery, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
| | - Shiuh-Bin Fang
- Division of Pediatric Gastroenterology and Hepatology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical UniversityTaipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical UniversityTaipei, Taiwan
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Wang KC, Hsu YH, Huang YN, Chen TH, Lin JH, Hsuan SL, Chien MS, Lee WC, Yeh KS. A low-pH medium in vitro or the environment within a macrophage decreases the transcriptional levels of fimA, fimZ and lrp in Salmonella enterica serovar Typhimurium. J Biosci 2014; 38:499-507. [PMID: 23938383 DOI: 10.1007/s12038-013-9347-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many Salmonella Typhimurium isolates produce type 1 fimbriae and exhibit fimbrial phase variation in vitro. Static broth culture favours the production of fimbriae, while solid agar medium inhibits the generation of these appendages. Little information is available regarding whether S. Typhimurium continues to produce type 1 fimbriae during in vivo growth. We used a type 1 fimbrial phase-variable strain S. Typhimurium LB5010 and its derivatives to infect RAW 264.7 macrophages. Following entry into macrophages, S. Typhimurium LB5010 gradually decreased the transcript levels of fimbrial subunit gene fimA, positive regulatory gene fimZ, and global regulatory gene lrp. A similar decrease in transcript levels was detected by RT-PCRwhen the pH of static brothmediumwas shifted frompH 7 to amore acidic pH 4. A fimA-deleted strain continued to multiply within macrophages as did the parental strain. An lrp deletion strain was unimpaired for in vitro growth at pH 7 or pH 4, while a strain harboring an lrp-containing plasmid exhibited impaired in vitro growth at pH 4. We propose that acidic medium, which resembles one aspect of the intracellular environment in a macrophage, inhibits type 1 fimbrial production by down-regulation of the expression of lrp, fimZ and fimA.
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Affiliation(s)
- Ke-Chuan Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Wang KC, Hsu YH, Huang YN, Lin JH, Yeh KS. FimY of Salmonella enterica serovar Typhimurium functions as a DNA-binding protein and binds the fimZ promoter. Microbiol Res 2013; 169:496-503. [PMID: 24462182 DOI: 10.1016/j.micres.2013.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 12/02/2013] [Accepted: 12/08/2013] [Indexed: 11/17/2022]
Abstract
Salmonella enterica serovar Typhimurium produces type 1 fimbriae with binding specificity to mannose residues. Elements involved in fimbrial structural biosynthesis, transport, and regulation are encoded by the fim gene cluster. FimZ, FimY, FimW, STM0551, and an arginine transfer RNA (fimU) were previously demonstrated to regulate fimbrial expression. The amino acid sequences of the C-terminal portion of FimY revealed similarity with those of LuxR-like proteins. Electrophoretic mobility shift assays indicated that FimY possessed DNA-binding capacity and bound a 605-bp DNA fragment spanning the intergenic region between fimY and fimZ, while a FimY protein harboring a double mutation in the C-terminal helix-turn-helix region containing a glycine (G) to aspartate (D) substitution at residue 189 and isoleucine (I) to lysine (K) substitution at residue 195 lost its ability to bind this DNA fragment. A lux box sequence (5'-TCTGTTATTACATAACAAATACT-3') within the fimZ promoter was required for binding. None of the DNA fragments derived from the promoters for fimA, fimY, or fimW was shifted by FimY. Pull-down assays showed that there were physical protein/protein interactions between FimY and FimZ. We propose that in the regulatory circuit of type 1 fimbriae, FimY functions as a DNA-binding protein to activate fimZ, and a FimY-FimZ protein complex may form to regulate other fim genes. Confirming these proposals requires further study.
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Affiliation(s)
- Ke-Chuan Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei 11031, Taiwan
| | - Yuan-Hsun Hsu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei 11031, Taiwan; Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei 11031, Taiwan
| | - Yi-Ning Huang
- Department of Veterinary Medicine, School of Veterinary Medicine, College of Bioresources and Agriculture, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 10617, Taiwan
| | - Jiunn-Horng Lin
- Department of Veterinary Medicine, School of Veterinary Medicine, College of Bioresources and Agriculture, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 10617, Taiwan; Division of Animal Medicine, Animal Technology Institute Taiwan, Chunan, Miaoli 35053, Taiwan
| | - Kuang-Sheng Yeh
- Department of Veterinary Medicine, School of Veterinary Medicine, College of Bioresources and Agriculture, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 10617, Taiwan.
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Identification of Salmonella enterica serovar Pullorum antigenic determinants expressed in vivo. Infect Immun 2013; 81:3119-27. [PMID: 23774596 DOI: 10.1128/iai.00145-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Salmonella enterica serovar Pullorum affecting poultry causes pullorum disease and results in severe economic loss in the poultry industry. Currently, it remains a major threat in countries with poor poultry surveillance and no efficient control measures. As S. Pullorum could induce strong humoral immune responses, we applied an immunoscreening technique, the in vivo-induced antigen technology (IVIAT), to identify immunogenic bacterial proteins expressed or upregulated during S. Pullorum infection. Convalescent-phase sera from chickens infected with S. Pullorum were pooled, adsorbed against antigens expressed in vitro, and used to screen an S. Pullorum genomic expression library. Forty-five proteins were screened out, and their functions were implicated in molecular biosynthesis and degradation, transport, metabolism, regulation, cell wall synthesis and antibiotic resistance, environmental adaptation, or putative functions. In addition, 11 of these 45 genes were assessed for their differential expression by quantitative real-time reverse transcription-PCR (RT-PCR), revealing that 9 of 11 genes were upregulated to different degrees under in vivo conditions, especially the regulator of virulence determinants, phoQ. Then, four in vivo-induced proteins (ShdA, PhoQ, Cse3, and PbpC) were tested for their immunoreactivity in 28 clinical serum samples from chickens infected with S. Pullorum. The rate of detection of antibodies against ShdA reached 82% and was the highest among these proteins. ShdA is a host colonization factor known to be upregulated in vivo and related to the persistence of S. Typhimurium in the intestine. Furthermore, these antigens identified by IVIAT warrant further evaluation for their contributions to pathogenesis, and more potential roles, such as diagnostic, therapeutic, and preventive uses, need to be developed in future studies.
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Deletions in the pyruvate pathway of Salmonella Typhimurium alter SPI1-mediated gene expression and infectivity. J Anim Sci Biotechnol 2013; 4:5. [PMID: 23442379 PMCID: PMC3608087 DOI: 10.1186/2049-1891-4-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/20/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Salmonella enterica serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands (SPI), producing the major effector proteins of virulence. Previously, we identified two genes of Salmonella pyruvate metabolism that were up-regulated during chicken cell infection: pyruvate formate lyase I (pflB) and bifunctional acetaldehyde-CoA/alcohol dehydrogenase (adhE). We were therefore interested in examining the role these genes may play in the transmission of Salmonella to humans. METHODS Mutant strains of Salmonella with single gene deletions for pflB and adhE were created. Invasion and growth in human HCT-8 intestinal epithelial cells and THP-1 macrophages was examined. Quantitative PCR was performed on 19 SPI-1 genes. RESULTS In HCT-8 cells, both mutant strains had significantly higher intracellular counts than the wild-type from 4 to 48 h post-infection. Various SPI-1 genes in the mutants were up-regulated over the wild-type as early as 1 h and lasting until 24 h post-infection. In THP-1 cells, no significant difference in internal Salmonella counts was observed; however, SPI-1 genes were largely down-regulated in the mutants during the time-course of infection. We also found five SPI-1 genes - hilA, hilC hilD, sicP and rtsA - which were up-regulated in at least one of the mutant strains in log-phase broth cultures alone. We have therefore identified a set of SPI-1 virulence genes whose regulation is effected by the central metabolism of Salmonella.
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Pathogenicity of dodecyltrimethylammonium chloride-resistant Salmonella enterica. Appl Environ Microbiol 2013; 79:2371-6. [PMID: 23377943 DOI: 10.1128/aem.03228-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella infection causes a self-limiting gastroenteritis in humans but can also result in a life-threatening invasive disease, especially in old, young, and/or immunocompromised patients. The prevalence of antimicrobial and multidrug-resistant Salmonella has increased worldwide since the 1980s. However, the impact of antimicrobial resistance on the pathogenicity of Salmonella strains is not well described. In our study, a microarray was used to screen for differences in gene expression between a parental strain and a strain of Salmonella enterica serovar Enteritidis with reduced susceptibility (SRS) to the widely used antimicrobial sanitizer dodecyltrimethylammonium chloride (DTAC). Three of the genes, associated with adhesion, invasion, and intracellular growth (fimA, csgG, and spvR), that showed differences in gene expression of 2-fold or greater were chosen for further study. Real-time reverse transcriptase PCR (real-time RT-PCR) was used to confirm the microarray data and to compare the expression levels of these genes in the parental strain and four independently derived SRS strains. All SRS strains showed lower levels of gene expression of fimA and csgG than those of the parental strain. Three of the four SRS strains showed lower levels of spvR gene expression while one SRS strain showed higher levels of spvR gene expression than those of the parental strain. Transmission electron microscopy determined that fimbriae were absent in the four SRS strains but copiously present in the parental strain. All four SRS strains demonstrated a significantly reduced ability to invade tissue culture cells compared to the parental strains, suggesting reduced pathogenicity of the SRS strains.
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Wang KC, Hsu YH, Huang YN, Yeh KS. A previously uncharacterized gene stm0551 plays a repressive role in the regulation of type 1 fimbriae in Salmonella enterica serotype Typhimurium. BMC Microbiol 2012; 12:111. [PMID: 22716649 PMCID: PMC3487979 DOI: 10.1186/1471-2180-12-111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/07/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Salmonella enterica serotype Typhimurium produces surface-associated fimbriae that facilitate adherence of the bacteria to a variety of cells and tissues. Type 1 fimbriae with binding specificity to mannose residues are the most commonly found fimbrial type. In vitro, static-broth culture favors the growth of S. Typhimurium with type 1 fimbriae, whereas non-type 1 fimbriate bacteria are obtained by culture on solid-agar media. Previous studies demonstrated that the phenotypic expression of type 1 fimbriae is the result of the interaction and cooperation of the regulatory genes fimZ, fimY, fimW, and fimU within the fim gene cluster. Genome sequencing revealed a novel gene, stm0551, located between fimY and fimW that encodes an 11.4-kDa putative phosphodiesterase specific for the bacterial second messenger cyclic-diguanylate monophosphate (c-di-GMP). The role of stm0551 in the regulation of type 1 fimbriae in S. Typhimurium remains unclear. RESULTS A stm0551-deleted stain constructed by allelic exchange constitutively produced type 1 fimbriae in both static-broth and solid-agar medium conditions. Quantative RT-PCR revealed that expression of the fimbrial major subunit gene, fimA, and one of the regulatory genes, fimZ, were comparably increased in the stm0551-deleted strain compared with those of the parental strain when grown on the solid-agar medium, a condition that normally inhibits expression of type 1 fimbriae. Following transformation with a plasmid possessing the coding sequence of stm0551, expression of fimA and fimZ decreased in the stm0551 mutant strain in both culture conditions, whereas transformation with the control vector pACYC184 relieved this repression. A purified STM0551 protein exhibited a phosphodiesterase activity in vitro while a point mutation in the putative EAL domain, substituting glutamic acid (E) with alanine (A), of STM0551 or a FimY protein abolished this activity. CONCLUSIONS The finding that the stm0551 gene plays a negative regulatory role in the regulation of type 1 fimbriae in S. Typhimurium has not been reported previously. The possibility that degradation of c-di-GMP is a key step in the regulation of type 1 fimbriae warrants further investigation.
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Affiliation(s)
- Ke-Chuan Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taiwan
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Kisiela DI, Chattopadhyay S, Libby SJ, Karlinsey JE, Fang FC, Tchesnokova V, Kramer JJ, Beskhlebnaya V, Samadpour M, Grzymajlo K, Ugorski M, Lankau EW, Mackie RI, Clegg S, Sokurenko EV. Evolution of Salmonella enterica virulence via point mutations in the fimbrial adhesin. PLoS Pathog 2012; 8:e1002733. [PMID: 22685400 PMCID: PMC3369946 DOI: 10.1371/journal.ppat.1002733] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 04/20/2012] [Indexed: 11/18/2022] Open
Abstract
Whereas the majority of pathogenic Salmonella serovars are capable of infecting many different animal species, typically producing a self-limited gastroenteritis, serovars with narrow host-specificity exhibit increased virulence and their infections frequently result in fatal systemic diseases. In our study, a genetic and functional analysis of the mannose-specific type 1 fimbrial adhesin FimH from a variety of serovars of Salmonella enterica revealed that specific mutant variants of FimH are common in host-adapted (systemically invasive) serovars. We have found that while the low-binding shear-dependent phenotype of the adhesin is preserved in broad host-range (usually systemically non-invasive) Salmonella, the majority of host-adapted serovars express FimH variants with one of two alternative phenotypes: a significantly increased binding to mannose (as in S. Typhi, S. Paratyphi C, S. Dublin and some isolates of S. Choleraesuis), or complete loss of the mannose-binding activity (as in S. Paratyphi B, S. Choleraesuis and S. Gallinarum). The functional diversification of FimH in host-adapted Salmonella results from recently acquired structural mutations. Many of the mutations are of a convergent nature indicative of strong positive selection. The high-binding phenotype of FimH that leads to increased bacterial adhesiveness to and invasiveness of epithelial cells and macrophages usually precedes acquisition of the non-binding phenotype. Collectively these observations suggest that activation or inactivation of mannose-specific adhesive properties in different systemically invasive serovars of Salmonella reflects their dynamic trajectories of adaptation to a life style in specific hosts. In conclusion, our study demonstrates that point mutations are the target of positive selection and, in addition to horizontal gene transfer and genome degradation events, can contribute to the differential pathoadaptive evolution of Salmonella.
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Affiliation(s)
- Dagmara I. Kisiela
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Sujay Chattopadhyay
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Stephen J. Libby
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Joyce E. Karlinsey
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Ferric C. Fang
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Veronika Tchesnokova
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Jeremy J. Kramer
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Viktoriya Beskhlebnaya
- Institute for Environmental Health, Lake Forest Park, Washington, United States of America
| | - Mansour Samadpour
- Institute for Environmental Health, Lake Forest Park, Washington, United States of America
| | - Krzysztof Grzymajlo
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
| | - Maciej Ugorski
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
| | - Emily W. Lankau
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, United States of America
| | - Roderick I. Mackie
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, United States of America
| | - Steven Clegg
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Evgeni V. Sokurenko
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Wu KH, Wang KC, Lee LW, Huang YN, Yeh KS. A constitutively mannose-sensitive agglutinating Salmonella enterica subsp. enterica serovar typhimurium strain, carrying a transposon in the fimbrial usher gene stbC, exhibits multidrug resistance and flagellated phenotypes. ScientificWorldJournal 2012; 2012:280264. [PMID: 22654583 PMCID: PMC3361161 DOI: 10.1100/2012/280264] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 01/23/2012] [Indexed: 01/08/2023] Open
Abstract
Static broth culture favors Salmonella enterica subsp. enterica serovar Typhimurium to produce type 1 fimbriae, while solid agar inhibits its expression. A transposon inserted in stbC, which would encode an usher for Stb fimbriae of a non-flagellar Salmonella enterica subsp. enterica serovar Typhimurium LB5010 strain, conferred it to agglutinate yeast cells on both cultures. RT-PCR revealed that the expression of the fimbrial subunit gene fimA, and fimZ, a regulatory gene of fimA, were both increased in the stbC mutant when grown on LB agar; fimW, a repressor gene of fimA, exhibited lower expression. Flagella were observed in the stbC mutant and this phenotype was correlated with the motile phenotype. Microarray data and RT-PCR indicated that the expression of three genes, motA, motB, and cheM, was enhanced in the stbC mutant. The stbC mutant was resistant to several antibiotics, consistent with the finding that expression of yhcQ and ramA was enhanced. A complementation test revealed that transforming a recombinant plasmid possessing the stbC restored the mannose-sensitive agglutination phenotype to the stbC mutant much as that in the parental Salmonella enterica subsp. enterica serovar Typhimurium LB5010 strain, indicating the possibility of an interplay of different fimbrial systems in coordinating their expression.
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Affiliation(s)
- Kuan-Hsun Wu
- Department of Pediatrics, Wan Fang Hospital, Taipei Medical University, Taipei 116, Taiwan
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