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Yao T, Huang Y, Huai Z, Liu X, Liu X, Liu Y, Sun H, Pang Y. Response mechanisms to acid stress promote LF82 replication in macrophages. Front Cell Infect Microbiol 2023; 13:1255083. [PMID: 37881369 PMCID: PMC10595154 DOI: 10.3389/fcimb.2023.1255083] [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: 07/08/2023] [Accepted: 09/25/2023] [Indexed: 10/27/2023] Open
Abstract
Background Adherent-invasive E. coli (AIEC) LF82 is capable of adhering to and invading intestinal epithelial cells, as well as replicating within macrophages without inducing host cell death. Methods We compared the transcriptomics of LF82 at pH=7.5 and pH=5.8 by RNA-sequencing, and qRT-PCR verified differentially expressed genes (DEGs). The deletion mutants of DEGs in the treatment group (pH=5.8) compared to the control group (pH=7.5) were constructed by λ recombinant. The replication differences between the mutants and WT infected Raw 264.7 at 24 h.p.i were analyzed by combining LB solid plate count and confocal observation. NH4Cl and chloroquine diphosphate (CQ) were used for acid neutralization to study the effect of pH on the replication of LF82 in macrophages. Na2NO3 was added to RPMI 1640 to study the effect of nitrate on the replication of LF82 in macrophages. 0.3% solid LB was used for flagellar motility assay and Hela was used to study flagellar gene deletion mutants and WT adhesion and invasion ability. Results In this study, we found that infection with LF82 results in acidification of macrophages. Subsequent experiments demonstrated that an intracellular acidic environment is necessary for LF82 replication. Transcriptome and phenotypic analysis showed that high expression of acid shock genes and acid fitness genes promotes LF82 replication in macrophages. Further, we found that the replication of LF82 in macrophages was increased under nitrate treatment, and nitrogen metabolism genes of LF82 were upregulated in acid treatment. The replication in macrophages of ΔnarK, ΔnarXL, ΔnarP, and Δhmp were decreased. In addition, we found that the expression of flagellar genes was downregulated in acidic pH and after LF82 invading macrophages. Motility assay shows that the movement of LF82 on an acidic semisolid agar plate was limited. Further results showed that ΔfliC and ΔfliD decreased in motility, adhesion ability, and invasion of host cells, but no significant effect on replication in macrophages was observed. Conclusion In this study, we simulated the acidic environment in macrophages, combined with transcriptome technology, and explained from the genetic level that LF82 promotes replication by activating its acid shock and fitness system, enhancing nitrate utilization, and inhibiting flagellar function.
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Affiliation(s)
- Ting Yao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Yu Huang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Zimeng Huai
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Xingmei Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Xiaowen Liu
- Academy of Psychology and Behavior, Faculty of Psychology, Tianjin Normal University, Tianjin, China
| | - Yutao Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Hao Sun
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
| | - Yu Pang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
- The Key Laboratory of Molecular Microbiology and Technology, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Ministry of Education, Tianjin, China
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Hirose S, Ohya K, Yoshinari T, Ohnishi T, Mizukami K, Suzuki T, Takinami K, Suzuki T, Lee K, Iyoda S, Akeda Y, Yahata Y, Tsuchihashi Y, Sunagawa T, Hara-Kudo Y. Atypical diarrhoeagenic Escherichia coli in milk related to a large foodborne outbreak. Epidemiol Infect 2023; 151:e150. [PMID: 37694773 PMCID: PMC10540162 DOI: 10.1017/s0950268823001395] [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] [Indexed: 09/12/2023] Open
Abstract
A foodborne outbreak related to milk cartons served in school lunches occurred in June 2021, which involved more than 1,800 cases from 25 schools. The major symptoms were abdominal pain, diarrhoea, vomiting, and fever. Although major foodborne toxins and pathogens were not detected, a specific Escherichia coli strain, serotype OUT (OgGp9):H18, was predominantly isolated from milk samples related to the outbreak and most patients tested. The strains from milk and patient stool samples were identified as the same clone by core genome multilocus sequence typing and single-nucleotide polymorphism analysis. The strain was detected in milk samples served for two days related to the foodborne outbreak at a rate of 69.6% and levels of less than ten most probable number/100 mL but not on days unrelated to the outbreak. The acid tolerance of the strain for survival in the stomach was similar to that of enterohaemorrhagic E. coli O157:H7, and the same inserts in the chu gene cluster in the acid fitness island were genetically revealed. The pathogenicity of the strain was not clear; however, it was indicated that the causative pathogen was atypical diarrhoeagenic E. coli OUT (OgGp9):H18.
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Affiliation(s)
- Shouhei Hirose
- Division of Microbiology, National Institute of Health Sciences, Kanagawa, Japan
| | - Kenji Ohya
- Division of Microbiology, National Institute of Health Sciences, Kanagawa, Japan
| | - Tomoya Yoshinari
- Division of Microbiology, National Institute of Health Sciences, Kanagawa, Japan
| | - Takahiro Ohnishi
- Division of Microbiology, National Institute of Health Sciences, Kanagawa, Japan
| | | | | | | | - Takayoshi Suzuki
- Division of Molecular Target and Gene Therapy Products, National Institute of Health Sciences, Kanagawa, Japan
| | - Kenichi Lee
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yukihiro Akeda
- Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yuichiro Yahata
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yuuki Tsuchihashi
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tomimasa Sunagawa
- Center for Field Epidemic Intelligence, Research and Professional Development, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yukiko Hara-Kudo
- Division of Microbiology, National Institute of Health Sciences, Kanagawa, Japan
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3
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Wu P, Wang Q, Yang Q, Feng X, Liu X, Sun H, Yan J, Kang C, Liu B, Liu Y, Yang B. A Novel Role of the Two-Component System Response Regulator UvrY in Enterohemorrhagic Escherichia coli O157:H7 Pathogenicity Regulation. Int J Mol Sci 2023; 24:ijms24032297. [PMID: 36768620 PMCID: PMC9916836 DOI: 10.3390/ijms24032297] [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: 12/12/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important human pathogen causing severe diseases, such as hemorrhagic colitis and lethal hemolytic uremic syndrome. The signal-sensing capability of EHEC O157:H7 at specific host colonization sites via different two-component systems (TCSs) is closely related to its pathogenicity during infection. However, the types of systems involved and the regulatory mechanisms are not fully understood. Here, we investigated the function of the TCS BarA/UvrY regulator UvrY in the pathogenicity regulation of EHEC O157:H7. Our results showed that UvrY acts as a positive regulator of EHEC O157:H7 for cellular adherence and mouse colonization through the transcriptional activation of the locus for enterocyte effacement (LEE) pathogenic genes. Furthermore, this regulation is mediated by the LEE island master regulator, Ler. Our results highlight the significance of UvrY in EHEC O157:H7 pathogenicity and underline the unknown importance of BarA/UvrY in colonization establishment and intestinal adaptability during infection.
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Affiliation(s)
- Pan Wu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Qian Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Qian Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Xiaohui Feng
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Xingmei Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Hongmin Sun
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Jun Yan
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Chenbo Kang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
| | - Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
- Nankai International Advanced Research Institute, Nankai University, Shenzhen 518000, China
| | - Yutao Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
- Nankai International Advanced Research Institute, Nankai University, Shenzhen 518000, China
- Correspondence: (Y.L.); (B.Y.)
| | - Bin Yang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, China
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300457, China
- Correspondence: (Y.L.); (B.Y.)
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4
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Yu L, Zhang S, Xu Y, Mi X, Xing T, Li J, Zhang L, Gao F, Jiang Y. Acid resistance of E. coli O157:H7 and O26:H11 exposure to lactic acid revealed by transcriptomic analysis. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2020.110352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Liu Y, Li S, Li W, Wang P, Ding P, Li L, Wang J, Yang P, Wang Q, Xu T, Xiong Y, Yang B. RstA, a two-component response regulator, plays important roles in multiple virulence-associated processes in enterohemorrhagic Escherichia coli O157:H7. Gut Pathog 2019; 11:53. [PMID: 31695752 PMCID: PMC6824119 DOI: 10.1186/s13099-019-0335-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/24/2019] [Indexed: 01/09/2023] Open
Abstract
Background Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) causes bloody diarrhea and hemolytic-uremic syndrome. EHEC O157 encounters varied microenvironments during infection, and can efficiently adapt to these using the two-component system (TCS). Recently, a functional TCS, RstAB, has been implicated in the regulation of virulence of several bacterial pathogens. However, the regulatory function of RstAB in EHEC O157 is poorly understood. This study aimed at providing insights into the global effects of RstA on gene expression in EHEC O157. Results In the present study, we analyzed gene expression differences between the EHEC O157 wild-type strain and a ΔrstA mutant using RNA-seq technology. Genes with differential expression in the ΔrstA mutant compared to that in the wild-type strain were identified and grouped into clusters of orthologous categories. RstA promoted EHEC O157 LEE gene expression, adhesion in vitro, and colonization in vivo by indirect regulation. We also found that RstA could bind directly to the promoter region of hdeA and yeaI to enhance acid tolerance and decrease biofilm formation by modulating the concentration of c-di-GMP. Conclusions In summary, the RstAB TCS in EHEC O157 plays a major role in the regulation of virulence, acid tolerance, and biofilm formation. We clarified the regulatory function of RstA, providing an insight into mechanisms that may be potential drug targets for treatment of EHEC O157-related infections.
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Affiliation(s)
- Yutao Liu
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Shujie Li
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Wendi Li
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Peisheng Wang
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Peng Ding
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Lingyu Li
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Junyue Wang
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Pan Yang
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Qian Wang
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Tingting Xu
- 3Shenzhen Institute of Respiratory Diseases, The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Second Clinical Medical College (Shenzhen People's Hospital), Jinan University, Shenzhen, 518020 People's Republic of China
| | - Yingying Xiong
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
| | - Bin Yang
- 1The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Tianjin, 300071 People's Republic of China.,TEDA, Institute of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, 300457 People's Republic of China
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The Escherichia coli O157:H7 carbon starvation-inducible lipoprotein Slp contributes to initial adherence in vitro via the human polymeric immunoglobulin receptor. PLoS One 2019; 14:e0216791. [PMID: 31188867 PMCID: PMC6561548 DOI: 10.1371/journal.pone.0216791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 04/29/2019] [Indexed: 01/19/2023] Open
Abstract
Escherichia coli O157:H7 is the most well-studied serotype of the enterohemorrhagic E. coli (EHEC) class of E. coli intestinal pathogens and is responsible for many outbreaks of serious food-borne illness worldwide each year. Adherence mechanisms are a critical component of its pathogenesis, persistence in natural reservoirs, and environmental contamination. E. coli O157:H7 has a highly effective virulence operon, the Locus of Enterocyte Effacement (LEE), and its encoded intimate adherence mechanism is well characterized. However, factors involved in the preceding initial attachment are not well understood. In this study, we propose a mechanism of initial adherence used by E. coli O157:H7 in vitro. We describe a bacterial protein not previously reported to be involved in adherence, Slp, and its interactions with the human host protein polymeric immunoglobulin receptor (pIgR). The human pIgR has previously been shown to act as an adherence receptor for some mucosal pathogens and is highly expressed in the intestine. Following observation of significant colocalization between E. coli O157:H7 bacteria and pIgR location on Caco-2 cells, a co-immunoprecipitation (Co-IP) assay using a human recombinant Fc-tagged pIgR protein led to the identification of this protein. Disruption of Slp expression in E. coli O157:H7, through deletion of its encoding gene slp, produced a significant adherence deficiency to Caco-2 cells at early time points associated with initial adherence. Plasmid complementation of the slp gene fully restored the wild-type phenotype. Furthermore, immunofluorescence microscopy revealed evidence that this interaction is specific to the pathogenic strains of E. coli tested and not the nonpathogenic control strain E. coli K12. Additionally, deletion of slp gene resulted in the absence of the corresponding protein band in further Co-IP assays, while the plasmid-encoded slp gene complementation of the deletion mutant strain restored the wild-type pattern. These data support the proposal that Slp directly contributes to initial adherence, with the pIgR protein as its proposed receptor.
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Liu CJ, Lin CT, Chiang JD, Lin CY, Tay YX, Fan LC, Peng KN, Lin CH, Peng HL. RcsB regulation of the YfdX-mediated acid stress response in Klebsiella pneumoniae CG43S3. PLoS One 2019; 14:e0212909. [PMID: 30818355 PMCID: PMC6394985 DOI: 10.1371/journal.pone.0212909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 02/12/2019] [Indexed: 12/31/2022] Open
Abstract
In Klebsiella pneumoniae CG43S3, deletion of the response regulator gene rcsB reduced the capsular polysaccharide amount and survival on exposure to acid stress. A comparison of the pH 4.4-induced proteomes between CG43S3 and CG43S3ΔrcsB revealed numerous differentially expressed proteins and one of them, YfdX, which has recently been reported as a periplasmic protein, was absent in CG43S3ΔrcsB. Acid survival analysis was then conducted to determine its role in the acid stress response. Deletion of yfdX increased the sensitivity of K. pneumoniae CG43S3 to a pH of 2.5, and transforming the mutant with a plasmid carrying yfdX restored the acid resistance (AR) levels. In addition, the effect of yfdX deletion was cross-complemented by the expression of the periplasmic chaperone HdeA. Furthermore, the purified recombinant protein YfdX reduced the acid-induced protein aggregation, suggesting that YfdX as well as HdeA functions as a chaperone. The following promoter activity measurement revealed that rcsB deletion reduced the expression of yfdX after the bacteria were subjected to pH 4.4 adaptation. Western blot analysis also revealed that YfdX production was inhibited by rcsB deletion and only the plasmid expressing RcsB or the nonphosphorylated form of RcsB, RcsBD56A, could restore the YfdX production, and the RcsB-mediated complementation was no longer observed when the sensor kinase RcsD gene was deleted. In conclusion, this is the first study demonstrating that YfdX may be involved in the acid stress response as a periplasmic chaperone and that RcsB positively regulates the acid stress response partly through activation of yfdX expression. Moreover, the phosphorylation status of RcsB may affect the YfdX expression under acidic conditions.
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Affiliation(s)
- Chia-Jui Liu
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Ching-Ting Lin
- School of Chinese Medicine, China Medical University, Taichung, Taiwan, Republic of China
| | - Jo-Di Chiang
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Chen-Yi Lin
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Yen-Xi Tay
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Li-Cheng Fan
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Kuan-Nan Peng
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Chih-Huan Lin
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Hwei-Ling Peng
- Department of Biological Science and Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
- Institute of Molecular Medicine and Biological Technology, School of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
- * E-mail:
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8
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Stress Resistance Development and Genome-Wide Transcriptional Response of Escherichia coli O157:H7 Adapted to Sublethal Thymol, Carvacrol, and trans-Cinnamaldehyde. Appl Environ Microbiol 2018; 84:AEM.01616-18. [PMID: 30217837 DOI: 10.1128/aem.01616-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/02/2018] [Indexed: 01/05/2023] Open
Abstract
Thymol, carvacrol, and trans-cinnamaldehyde are essential oil (EO) compounds with broad-spectrum antimicrobial activities against foodborne pathogens, including Escherichia coli O157:H7. However, little is known regarding direct resistance and cross-resistance development in E. coli O157:H7 after adaptation to sublethal levels of these compounds, and information is scarce on microbial adaptive responses at a molecular level. The present study demonstrated that E. coli O157:H7 was able to grow in the presence of sublethal thymol (1/2T), carvacrol (1/2C), or trans-cinnamaldehyde (1/2TC), displaying an extended lag phase duration and a lower maximum growth rate. EO-adapted cells developed direct resistance against lethal EO treatments and cross-resistance against heat (58°C) and oxidative (50 mM H2O2) stresses. However, no induction of acid resistance (simulated gastric fluid, pH 1.5) was observed. RNA sequencing revealed a large number (310 to 338) of differentially expressed (adjusted P value [Padj ], <0.05; fold change, ≥5) genes in 1/2T and 1/2C cells, while 1/2TC cells only showed 27 genes with altered expression. In accordance with resistance phenotypes, the genes related to membrane, heat, and oxidative stress responses and genes related to iron uptake and metabolism were upregulated. Conversely, virulence genes associated with motility, biofilm formation, and efflux pumps were repressed. This study demonstrated the development of direct resistance and cross-resistance and characterized whole-genome transcriptional responses in E. coli O157:H7 adapted to sublethal thymol, carvacrol, or trans-cinnamaldehyde. The data suggested that caution should be exercised when using EO compounds as food antimicrobials, due to the potential stress resistance development in E. coli O157:H7.IMPORTANCE The present study was designed to understand transcriptomic changes and the potential development of direct and cross-resistance in essential oil (EO)-adapted Escherichia coli O157:H7. The results demonstrated altered growth behaviors of E. coli O157:H7 during adaptation in sublethal thymol, carvacrol, and trans-cinnamaldehyde. Generally, EO-adapted bacteria showed enhanced resistance against subsequent lethal EO, heat, and oxidative stresses, with no induction of acid resistance in simulated gastric fluid. A transcriptomic analysis revealed the upregulation of related stress resistance genes and a downregulation of various virulence genes in EO-adapted cells. This study provides new insights into microbial EO adaptation behaviors and highlights the risk of resistance development in adapted bacteria.
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García V, Montero I, Bances M, Rodicio R, Rodicio MR. Incidence and Genetic Bases of Nitrofurantoin Resistance in Clinical Isolates of Two Successful Multidrug-Resistant Clones of Salmonella enterica Serovar Typhimurium: Pandemic "DT 104" and pUO-StVR2. Microb Drug Resist 2016; 23:405-412. [PMID: 27809653 DOI: 10.1089/mdr.2016.0227] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In this study, the incidence and genetic bases of nitrofurantoin resistance were established for clinical isolates of two successful clones of Salmonella enterica serovar Typhimurium, the pandemic "DT 104" and the pUO-StVR2 clone. A total of 61 "DT 104" and 40 pUO-StVR2 isolates recovered from clinical samples during 2008-2014 and assigned to different phage types, were tested for nitrofurantoin susceptibility. As previously shown for older isolates, all newly tested pUO-StVR2 isolates were highly resistant to nitrofurantoin (minimal inhibitory concentration [MIC] of 128 μg/ml), while 42.6%, 24.6%, and 32.8% of the "DT 104" isolates were susceptible, showed intermediate resistance or were highly resistant, with MICs of 8, 64, and 128 μg/ml, respectively. The genetic bases of nitrofurantoin resistance were established by PCR amplification and sequencing of the nfsA and nfsB genes encoding oxygen-insensitive nitroreductases. pUO-StVR2 isolates shared identical alterations in both nfsA (IS1 inserted into the coding region) and nfsB (in frame duplication of two codons). "DT 104" isolates with intermediate or high resistance had a missense mutation affecting the start codon of nfsA, while a single resistant isolate carried an additional frameshift mutation affecting nfsB. Complementation studies, performed with wild-type nfsA and nfsB, cloned independently and together into low and high copy-number vectors, confirmed NfsA and NfsB as responsible for nitrofurantoin toxicity. The same alterations persisted along time in isolates of each clone belonging to different phage types. Accordingly, changes leading to nitrofurantoin resistance have probably occurred before phage type diversification.
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Affiliation(s)
- Vanesa García
- 1 Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Universidad de Oviedo , Oviedo, Asturias, Spain
| | - Ignacio Montero
- 1 Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Universidad de Oviedo , Oviedo, Asturias, Spain
| | - Margarita Bances
- 2 Laboratorio de Salud Pública, Consejería de Sanidad , Oviedo, Asturias, Spain
| | - Rosaura Rodicio
- 3 Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Universidad de Oviedo , Oviedo, Asturias, Spain
| | - M Rosario Rodicio
- 1 Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Universidad de Oviedo , Oviedo, Asturias, Spain
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Comparative proteomics reveal distinct chaperone-client interactions in supporting bacterial acid resistance. Proc Natl Acad Sci U S A 2016; 113:10872-7. [PMID: 27621474 DOI: 10.1073/pnas.1606360113] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
HdeA and HdeB constitute the essential chaperone system that functions in the unique periplasmic space of Gram-negative enteric bacteria to confer acid resistance. How this two-chaperone machinery cooperates to protect a broad range of client proteins from acid denaturation while avoiding nonspecific binding during bacterial passage through the highly acidic human stomach remains unclear. We have developed a comparative proteomic strategy that combines the genetically encoded releasable protein photocross-linker with 2D difference gel electrophoresis, which allows an unbiased side-by-side comparison of the entire client pools from these two acid-activated chaperones in Escherichia coli Our results reveal distinct client specificities between HdeA and HdeB in vivo that are determined mainly by their different responses to pH stimulus. The intracellular acidity serves as an environmental cue to determine the folding status of both chaperones and their clients, enabling specific chaperone-client binding and release under defined pH conditions. This cooperative and synergistic mode of action provides an efficient, economical, flexible, and finely tuned protein quality control strategy for coping with acid stress.
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11
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McLeod A, Måge I, Heir E, Axelsson L, Holck AL. Effect of relevant environmental stresses on survival of enterohemorrhagic Escherichia coli in dry-fermented sausage. Int J Food Microbiol 2016; 229:15-23. [PMID: 27089033 DOI: 10.1016/j.ijfoodmicro.2016.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 02/09/2016] [Accepted: 04/03/2016] [Indexed: 01/24/2023]
Abstract
Dry-fermented sausages (DFSs) have been linked to several serious foodborne outbreaks of enterohemorrhagic Escherichia coli (EHEC). The ability of pathogens to utilize adaptive responses to different stressful conditions intended to control their growth in foods, food preparation and production processes may enhance their survival. In certain cases, induced tolerance to one type of stress may lead to enhanced resistance to the applied stress as well as to other stresses. We exposed two EHEC strains, MF3582 of serotype O157:H- and MF5554 of serogroup O145, to different stresses commonly encountered during a production process. The two EHEC strains, previously shown to have different abilities to survive DFS production process conditions, were subjected to low temperatures (4°C and 12°C), 5% NaCl or 1% lactic acid for 6days prior to being added to sausage batters. Survival of EHEC was recorded in salami of two recipes, fermented at two temperatures (20°C and 30°C). The results showed that recipe type had the largest impact on EHEC reductions where Moderate recipe (MR) salami batters containing increased levels of NaCl, glucose and NaNO2 provided enhanced EHEC reductions in salami (2.6 log10) compared to Standard recipe (SR) salami (1.7 log10). Effects of pre-exposure stresses were dependent both on strain and recipe. While acid adaptation of MF5554 provided enhanced log10 reductions from 2.0 to 3.0 in MR sausages, adaptation to a combination of acid and salt stress showed the opposite effect in SR sausages with reductions of only 1.1 log10 as compared to the average of 1.8 log10 for the other SR sausages. Otherwise, the salt and acid adaptation single stresses had relatively small effects on EHEC survival through the DFS production process and subsequent storage and freeze/thaw treatments. Growing cells and cells frozen in batter survived poorly in MR sausages with an average reduction of 3.4 and 3.2 log10, respectively. The reductions of EHEC after storage of DFS increased with higher temperature and storage time. Up to 3.7 log10 additional reduction was obtained when MF3582 was stored for 2months at 20°C. In conclusion, adaptation of EHEC to acid, salt and low temperatures prior to being introduced in a DFS production process has limited, but strain dependent effects on EHEC reductions. Producers should avoid conditions leading to acid and salt adapted cells that can contaminate the sausage batter. Recipe parameters had the largest impact on EHEC reductions while storage at 20°C is effective for enhanced reductions in finished products.
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Affiliation(s)
- Anette McLeod
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Ingrid Måge
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Even Heir
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Lars Axelsson
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway
| | - Askild L Holck
- Nofima AS, Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, N-1431 Ås, Norway.
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12
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Mei GY, Tang J, Carey C, Bach S, Kostrzynska M. The effect of oxidative stress on gene expression of Shiga toxin-producing Escherichia coli (STEC) O157:H7 and non-O157 serotypes. Int J Food Microbiol 2015; 215:7-15. [DOI: 10.1016/j.ijfoodmicro.2015.07.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 01/05/2023]
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Ojima-Kato T, Yamamoto N, Iijima Y, Tamura H. Assessing the performance of novel software Strain Solution on automated discrimination of Escherichia coli serotypes and their mixtures using matrix-assisted laser desorption ionization-time of flight mass spectrometry. J Microbiol Methods 2015; 119:233-8. [DOI: 10.1016/j.mimet.2015.11.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/05/2015] [Accepted: 11/07/2015] [Indexed: 11/26/2022]
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14
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Joerger RD, Choi S. Contribution of the hdeB-like gene (SEN1493) to survival of Salmonella enterica enteritidis Nal(R) at pH 2. Foodborne Pathog Dis 2015; 12:353-9. [PMID: 25659065 DOI: 10.1089/fpd.2014.1878] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Periplasmic proteins are particularly vulnerable to denaturation upon entry into a highly acid environment. In Escherichia coli, a level of protection of these proteins is afforded by acid-inducible chaperonins encoded by hdeAB. In contrast, Salmonella enterica only harbors an hdeB-like gene and it is currently not known what function it plays in this genus. In the present study, the hdeB-like gene was deleted in Salmonella enterica Enteritidis Nal(R) and Salmonella enterica Kentucky 3795. When grown overnight in tryptic soy broth (TSB) medium buffered at pH 5.5 and then exposed to TSB pH 2 for 20 min, Enteritidis wild-type strain experienced a 0.5-log10 reduction in colony-forming units, whereas the deletion strain's surviving cells were reduced by 1.6 log10. No difference in survival was observed in the corresponding Salmonella enterica Kentucky 3795 strains treated the same way. Exposure of the strains to pH 2.5 or 3 resulted in the same log reduction regardless of the presence of the hdeB-like gene. When wild-type and deletion strains of both serovars were grown in medium buffered at pH 7 prior to exposure to the acidic pHs, no difference in survival with respect to serovar or presence/absence of the hdeB-like gene was found. Salmonella enterica Enteritidis Nal(R) carrying its own or the intragenic region upstream of the hdeB-like from Salmonella enterica Kentucky 3795 cloned in front of the gfp gene from pFPV25 showed maximum fluorescence when grown at pH 5.5, whereas the corresponding plasmid-carrying Salmonella enterica Kentucky strains did not exhibit fluorescence regardless of the pH of the growth medium. Therefore, the hdeB-like gene in Salmonella enterica Enteritidis, but not in Salmonella enterica Kentucky 3795, contributed to survival at pH 2 and its expression is responsive to the pH of the medium.
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Affiliation(s)
- Rolf D Joerger
- Department of Animal and Food Sciences, University of Delaware , Newark, Delaware
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15
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De Biase D, Lund PA. The Escherichia coli Acid Stress Response and Its Significance for Pathogenesis. ADVANCES IN APPLIED MICROBIOLOGY 2015; 92:49-88. [PMID: 26003933 DOI: 10.1016/bs.aambs.2015.03.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Escherichia coli has a remarkable ability to survive low pH and possesses a number of different genetic systems that enable it to do this. These may be expressed constitutively, typically in stationary phase, or induced by growth under a variety of conditions. The activities of these systems have been implicated in the ability of E. coli to pass the acidic barrier of the stomach and to become established in the gastrointestinal tract, something causing serious infections. However, much of the work characterizing these systems has been done on standard laboratory strains of E. coli and under conditions which do not closely resemble those found in the human gut. Here we review what is known about acid resistance in E. coli as a model laboratory organism and in the context of its lifestyle as an inhabitant-sometimes an unwelcome one-of the human gut.
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Ojima-Kato T, Yamamoto N, Suzuki M, Fukunaga T, Tamura H. Discrimination of Escherichia coli O157, O26 and O111 from other serovars by MALDI-TOF MS based on the S10-GERMS method. PLoS One 2014; 9:e113458. [PMID: 25411793 PMCID: PMC4239071 DOI: 10.1371/journal.pone.0113458] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 10/26/2014] [Indexed: 11/23/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC), causes a potentially life-threatening infection in humans worldwide. Serovar O157:H7, and to a lesser extent serovars O26 and O111, are the most commonly reported EHEC serovars responsible for a large number of outbreaks. We have established a rapid discrimination method for E. coli serovars O157, O26 and O111 from other E. coli serovars, based on the pattern matching of mass spectrometry (MS) differences and the presence/absence of biomarker proteins detected in matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF MS). Three biomarkers, ribosomal proteins S15 and L25, and acid stress chaperone HdeB, with MS m/z peaks at 10138.6/10166.6, 10676.4/10694.4 and 9066.2, respectively, were identified as effective biomarkers for O157 discrimination. To distinguish serovars O26 and O111 from the others, DNA-binding protein H-NS, with an MS peak at m/z 15409.4/15425.4 was identified. Sequence analysis of the O157 biomarkers revealed that amino acid changes: Q80R in S15, M50I in L25 and one mutation within the start codon ATG to ATA in the encoded HdeB protein, contributed to the specific peak pattern in O157. We demonstrated semi-automated pattern matching using these biomarkers and successfully discriminated total 57 O157 strains, 20 O26 strains and 6 O111 strains with 100% reliability by conventional MALDI-TOF MS analysis, regardless of the sample conditions. Our simple strategy, based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method, therefore allows for the rapid and reliable detection of this pathogen and may prove to be an invaluable tool both clinically and in the food industry.
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Affiliation(s)
- Teruyo Ojima-Kato
- Hub of Knowledge Aichi, Aichi Science and Technology Foundation, Yakusa, Toyota, Aichi, Japan
- * E-mail: (TO); (HT)
| | - Naomi Yamamoto
- School of Agriculture, Meijo University, Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi, Japan
| | - Mayumi Suzuki
- School of Agriculture, Meijo University, Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi, Japan
| | - Tomohiro Fukunaga
- Japan Food Research Laboratories, Osu, Naka-ku, Nagoya, Aichi, Japan
| | - Hiroto Tamura
- School of Agriculture, Meijo University, Shiogamaguchi, Tenpaku-ku, Nagoya, Aichi, Japan
- * E-mail: (TO); (HT)
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Guan N, Shin HD, Chen RR, Li J, Liu L, Du G, Chen J. Understanding of how Propionibacterium acidipropionici respond to propionic acid stress at the level of proteomics. Sci Rep 2014; 4:6951. [PMID: 25377721 PMCID: PMC4223659 DOI: 10.1038/srep06951] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 10/10/2014] [Indexed: 11/29/2022] Open
Abstract
Propionic acid (PA) is an important platform chemical in the food, agriculture, and pharmaceutical industries and is mainly biosynthesized by propionibacteria. Acid tolerance in PA-producing strains is crucial. In previous work, we investigated the acid tolerance mechanism of Propionibacterium acidipropionici at microenvironmental levels by analyzing physiological changes in the parental strain and three PA-tolerant mutants obtained by genome shuffling. However, the molecular mechanism of PA tolerance in P. acidipropionici remained unclear. Here, we performed a comparative proteomics study of P. acidipropionici CGMCC 1.2230 and the acid-tolerant mutant P. acidipropionici WSH1105; MALDI-TOF/MS identified 24 proteins that significantly differed between the parental and shuffled strains. The differentially expressed proteins were mainly categorized as key components of crucial biological processes and the acid stress response. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to confirm differential expression of nine key proteins. Overexpression of the secretory protein glyceraldehyde-3-phosphate dehydrogenase and ATP synthase subunit α in Escherichia coli BL21 improved PA and acetic acid tolerance; overexpression of NADH dehydrogenase and methylmalonyl-CoA epimerase improved PA tolerance. These results provide new insights into the acid tolerance of P. acidipropionici and will facilitate the development of PA production through fermentation by propionibacteria.
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Affiliation(s)
- Ningzi Guan
- 1] Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China [2] Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Hyun-dong Shin
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta 30332, USA
| | - Rachel R Chen
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta 30332, USA
| | - Jianghua Li
- 1] Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China [2] Synergetic Innovation Center Of Food Safety and Nutrition, Wuxi 214122, China
| | - Long Liu
- 1] Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China [2] Synergetic Innovation Center Of Food Safety and Nutrition, Wuxi 214122, China
| | - Guocheng Du
- Synergetic Innovation Center Of Food Safety and Nutrition, Wuxi 214122, China
| | - Jian Chen
- Synergetic Innovation Center Of Food Safety and Nutrition, Wuxi 214122, China
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18
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Vivijs B, Moons P, Aertsen A, Michiels CW. Acetoin synthesis acquisition favors Escherichia coli growth at low pH. Appl Environ Microbiol 2014; 80:6054-61. [PMID: 25063653 PMCID: PMC4178668 DOI: 10.1128/aem.01711-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/17/2014] [Indexed: 11/20/2022] Open
Abstract
Some members of the family Enterobacteriaceae ferment sugars via the mixed-acid fermentation pathway. This yields large amounts of acids, causing strong and sometimes even lethal acidification of the environment. Other family members employ the 2,3-butanediol fermentation pathway, which generates comparatively less acidic and more neutral end products, such as acetoin and 2,3-butanediol. In this work, we equipped Escherichia coli MG1655 with the budAB operon, encoding the acetoin pathway, from Serratia plymuthica RVH1 and investigated how this affected the ability of E. coli to cope with acid stress during growth. Acetoin fermentation prevented lethal medium acidification by E. coli in lysogeny broth (LB) supplemented with glucose. It also supported growth and higher stationary-phase cell densities in acidified LB broth with glucose (pH 4.10 to 4.50) and in tomato juice (pH 4.40 to 5.00) and reduced the minimal pH at which growth could be initiated. On the other hand, the acetoin-producing strain was outcompeted by the nonproducer in a mixed-culture experiment at low pH, suggesting a fitness cost associated with acetoin production. Finally, we showed that acetoin production profoundly changes the appearance of E. coli on several diagnostic culture media. Natural E. coli strains that have laterally acquired budAB genes may therefore have escaped detection thus far. This study demonstrates the potential importance of acetoin fermentation in the ecology of E. coli in the food chain and contributes to a better understanding of the microbiological stability and safety of acidic foods.
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Affiliation(s)
- Bram Vivijs
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Pieter Moons
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Chris W Michiels
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (MS), Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
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19
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Cooper KK, Mandrell RE, Louie JW, Korlach J, Clark TA, Parker CT, Huynh S, Chain PS, Ahmed S, Carter MQ. Comparative genomics of enterohemorrhagic Escherichia coli O145:H28 demonstrates a common evolutionary lineage with Escherichia coli O157:H7. BMC Genomics 2014; 15:17. [PMID: 24410921 PMCID: PMC3893438 DOI: 10.1186/1471-2164-15-17] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 12/19/2013] [Indexed: 11/13/2022] Open
Abstract
Background Although serotype O157:H7 is the predominant enterohemorrhagic Escherichia coli (EHEC), outbreaks of non-O157 EHEC that cause severe foodborne illness, including hemolytic uremic syndrome have increased worldwide. In fact, non-O157 serotypes are now estimated to cause over half of all the Shiga toxin-producing Escherichia coli (STEC) cases, and outbreaks of non-O157 EHEC infections are frequently associated with serotypes O26, O45, O103, O111, O121, and O145. Currently, there are no complete genomes for O145 in public databases. Results We determined the complete genome sequences of two O145 strains (EcO145), one linked to a US lettuce-associated outbreak (RM13514) and one to a Belgium ice-cream-associated outbreak (RM13516). Both strains contain one chromosome and two large plasmids, with genome sizes of 5,737,294 bp for RM13514 and 5,559,008 bp for RM13516. Comparative analysis of the two EcO145 genomes revealed a large core (5,173 genes) and a considerable amount of strain-specific genes. Additionally, the two EcO145 genomes display distinct chromosomal architecture, virulence gene profile, phylogenetic origin of Stx2a prophage, and methylation profile (methylome). Comparative analysis of EcO145 genomes to other completely sequenced STEC and other E. coli and Shigella genomes revealed that, unlike any other known non-O157 EHEC strain, EcO145 ascended from a common lineage with EcO157/EcO55. This evolutionary relationship was further supported by the pangenome analysis of the 10 EHEC str ains. Of the 4,192 EHEC core genes, EcO145 shares more genes with EcO157 than with the any other non-O157 EHEC strains. Conclusions Our data provide evidence that EcO145 and EcO157 evolved from a common lineage, but ultimately each serotype evolves via a lineage-independent nature to EHEC by acquisition of the core set of EHEC virulence factors, including the genes encoding Shiga toxin and the large virulence plasmid. The large variation between the two EcO145 genomes suggests a distinctive evolutionary path between the two outbreak strains. The distinct methylome between the two EcO145 strains is likely due to the presence of a BsuBI/PstI methyltransferase gene cassette in the Stx2a prophage of the strain RM13514, suggesting a role of horizontal gene transfer-mediated epigenetic alteration in the evolution of individual EHEC strains.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Michelle Qiu Carter
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA 94710, USA.
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Abstract
In the United States, it is estimated that non-O157 Shiga toxin-producing Escherichia coli (STEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections are due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseases caused by non-O157 STEC are generally milder than those induced by O157 STEC; nonetheless, non-O157 STEC strains have also been associated with serious illnesses such as hemorrhagic colitis and hemolytic uremic syndrome, as well as death. Ruminants, particularly cattle, are reservoirs for both O157 and non-O157 STEC, which are transmitted to humans by person-to-person or animal contact and by ingestion of food or water contaminated with animal feces. Improved strategies to control STEC colonization and shedding in cattle and contamination of meat and produce are needed. In general, non-O157 STEC respond to stresses such as acid, heat, and other stresses induced during food preparation similar to O157 STEC. Similar to O157:H7, the top six non-O157 STEC are classified as adulterants in beef by the USDA Food Safety and Inspection Service, and regulatory testing for these pathogens began in June 2012. Due to the genetic and phenotypic variability of non-O157 STEC strains, the development of accurate and reliable methods for detection and isolation of these pathogens has been challenging. Since the non-O157 STEC are responsible for a large portion of STEC-related illnesses, more extensive studies on their physiology, genetics, pathogenicity, and evolution are needed in order to develop more effective control strategies.
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Affiliation(s)
- James L Smith
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA
| | - Pina M Fratamico
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA.
| | - Nereus W Gunther
- USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania, USA
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David M, Gollasch S, Leppäkoski E. Risk assessment for exemptions from ballast water management--the Baltic Sea case study. MARINE POLLUTION BULLETIN 2013; 75:205-217. [PMID: 23958222 DOI: 10.1016/j.marpolbul.2013.07.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 07/09/2013] [Accepted: 07/12/2013] [Indexed: 06/02/2023]
Abstract
The International Convention for the Control and Management of Ship's Ballast Water and Sediments sets requirements to prevent organism transfers. Vessels on certain routes can be exempted from such requirements based on risk assessment (RA). As the convention nears its entry into force, the interest in exemptions increases. Such RA should be conducted according to the International Maritime Organization G7 Guidelines. We present a RA study for exemptions applied to intra-Baltic shipping considering different RA methods, i.e., environmental matching, species specific method including target species and species biogeographical aspects. As reliable species data in the ports considered are unavailable and following the precautionary principle, no exemptions should be granted. To ensure data reliability, port baseline surveys and regular monitoring programs should be undertaken during the exemption period as new species found influence the RA result. The RA model prepared is considered as of value to other areas worldwide.
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Affiliation(s)
- Matej David
- David Consult, Korte 13e, SI-6310 Izola, Slovenia.
| | | | - Erkki Leppäkoski
- Åbo Akademi University, Department of Biosciences, FI-20500 Turku, Finland
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Smith JL, Fratamico PM. Effect of stress on non-O157 Shiga toxin-producing Escherichia coli. J Food Prot 2012; 75:2241-50. [PMID: 23212025 DOI: 10.4315/0362-028x.jfp-12-255] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC) strains have emerged as important foodborne pathogens worldwide. Non-O157 STEC serogroups O26, O45, O103, O111, O121, and O145 have been declared as adulterants in beef by the U. S. Department of Agriculture Food Safety and Inspection Service. While documentation is limited, treatments including heat and acid that have been shown to inactivate E. coli O157:H7 will likely also destroy non-O157 STEC; however, non-O157 STEC strains show variability in their responses to stress. It has been shown that non-O157 STEC may survive in fermented sausages and cheeses, and treatments such as high pressure may be necessary to eliminate non-O157 STEC from these products. The mechanisms used by non-O157 STEC to resist acid environments are similar to those used by O157:H7 strains and include the acid tolerance response, the oxidative system, and the glutamate and arginine decarboxylase systems. However, one study demonstrated that some non-O157 STEC strains utilize a chaperone-based acid stress response (HdeA and HdeB) to combat acidic conditions, which is lacking in E. coli O157:H7. Genomic studies suggest that while non-O157 STEC can cause diseases similar to those caused by E. coli O157:H7, O157 and non-O157 STECs have different evolutionary histories. Non-O157 STECs are a heterogeneous group of organisms, and there is currently a limited amount of information on their virulence, fitness, and stress responses, rendering it difficult to draw firm conclusions on their behavior when exposed to stress in the environment, in food, and during processing.
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Affiliation(s)
- James L Smith
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA 19038, USA.
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Fagerquist CK, Sultan O, Carter MQ. Possible evidence of amide bond formation between sinapinic acid and lysine-containing bacterial proteins by matrix-assisted laser desorption/ionization (MALDI) at 355 nm. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:2102-2114. [PMID: 23055076 DOI: 10.1007/s13361-012-0490-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/29/2012] [Accepted: 09/03/2012] [Indexed: 06/01/2023]
Abstract
We previously reported the apparent formation of matrix adducts of 3,5-dimethoxy-4-hydroxy-cinnamic acid (sinapinic acid or SA) via covalent attachment to disulfide bond-containing proteins (HdeA, Hde, and YbgS) from bacterial cell lysates ionized by matrix-assisted laser desorption/ionization (MALDI) time-of-flight-time-of-flight tandem mass spectrometry (TOF-TOF-MS/MS) and post-source decay (PSD). We also reported the absence of adduct formation when using α-cyano-4-hydroxycinnamic acid (CHCA) matrix. Further mass spectrometric analysis of disulfide-intact and disulfide-reduced over-expressed HdeA and HdeB proteins from lysates of gene-inserted E. coli plasmids suggests covalent attachment of SA occurs not at cysteine residues but at lysine residues. In this revised hypothesis, the attachment of SA is preceded by formation of a solid phase ammonium carboxylate salt between SA and accessible lysine residues of the protein during sample preparation under acidic conditions. Laser irradiation at 355 nm of the dried sample spot results in equilibrium retrogradation followed by nucleophilic attack by the amine group of lysine at the carbonyl group of SA and subsequent amide bond formation and loss of water. The absence of CHCA adducts suggests that the electron-withdrawing effect of the α-cyano group of this matrix may inhibit salt formation and/or amide bond formation. This revised hypothesis is supported by dissociative loss of SA (-224 Da) and the amide-bound SA (-206 Da) from SA-adducted HdeA and HdeB ions by MS/MS (PSD). It is proposed that cleavage of the amide-bound SA from the lysine side-chain occurs via rearrangement involving a pentacyclic transition state followed by hydrogen abstraction/migration and loss of 3-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-ynal (-206 Da).
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Affiliation(s)
- Clifton K Fagerquist
- Agricultural Research Service, US Department of Agriculture, Western Regional Research Center, 800 Buchanan Street, Albany, CA 94710, USA.
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RcsB contributes to the distinct stress fitness among Escherichia coli O157:H7 curli variants of the 1993 hamburger-associated outbreak strains. Appl Environ Microbiol 2012; 78:7706-19. [PMID: 22923406 DOI: 10.1128/aem.02157-12] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Curli are adhesive fimbriae of Enterobactericaeae and are involved in surface attachment, cell aggregation, and biofilm formation. We reported previously that curli-producing (C(+)) variants of E. coli O157:H7 (EcO157) were much more acid sensitive than their corresponding curli-deficient (C(-)) variants; however, this difference was not linked to the curli fimbriae per se. Here, we investigated the underlying molecular basis of this phenotypic divergence. We identified large deletions in the rcsB gene of C(+) variants isolated from the 1993 U.S. hamburger-associated outbreak strains. rcsB encodes the response regulator of the RcsCDB two-component signal transduction system, which regulates curli biogenesis negatively but acid resistance positively. Further comparison of stress fitness revealed that C(+) variants were also significantly more sensitive to heat shock but were resistant to osmotic stress and oxidative damage, similar to C(-) variants. Transcriptomics analysis uncovered a large number of differentially expressed genes between the curli variants, characterized by enhanced expression in C(+) variants of genes related to biofilm formation, virulence, catabolic activity, and nutrient uptake but marked decreases in transcription of genes related to various types of stress resistance. Supplying C(+) variants with a functional rcsB restored resistance to heat shock and acid challenge in cells but blocked curli production, confirming that inactivation of RcsB in C(+) variants was the basis of fitness segregation within the EcO157 population. This study provides an example of how genome instability of EcO157 promotes intrapopulation diversification, generating subpopulations carrying an array of distinct phenotypes that may confer the pathogen with survival advantages in diverse environments.
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Chaperone-dependent mechanisms for acid resistance in enteric bacteria. Trends Microbiol 2012; 20:328-35. [DOI: 10.1016/j.tim.2012.03.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 02/26/2012] [Accepted: 03/02/2012] [Indexed: 01/13/2023]
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