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Wi SM, Kim SK, Lee JB, Yoon JW. Acid tolerance of enterohemorrhagic Escherichia coli O157:H7 strain ATCC 43894 and its relationship with a large virulence plasmid pO157. Vet Microbiol 2023; 284:109833. [PMID: 37515979 DOI: 10.1016/j.vetmic.2023.109833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/19/2023] [Accepted: 07/17/2023] [Indexed: 07/31/2023]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen that causes a severe intestinal infection including hemolytic uremic syndrome in humans. Various factors contribute to its pathogenesis, including a large virulence plasmid pO157. This F-like 92-kb plasmid is isolated in virtually all clinical EHEC isolates, and is considered a hallmark of EHEC virulence. A previous report stated that removal of pO157 from EHEC ATCC 43894 induced overexpression of GadAB that are essential in glutamate-dependent acid resistance (GDAR) system, yet the mechanism remains elusive. Based on this observation, we surmised that pO157 is involved in the regulation of GDAR system. We comparatively analyzed 43894 and its pO157-cured (ΔpO157) mutant 277 for i) their acid resistance, ii) changes in the transcriptional profiles and iii) expression of GDAR associated genes/proteins. Survivability of 43894 upon exposure to acidic conditions was significantly lower than the ΔpO157 mutant. In addition, RNA-sequencing revealed that genes involved in GDAR were significantly down-regulated in 43894 when compared to the ΔpO157 mutant. Exogenous expression of GadE in 43894 led to expression of GadAB, suggesting possible intervention of pO157 in GDAR regulation. Despite these findings, reintroduction of pO157 into 277 did not reverted Gad overexpression. Likewise, removing pO157 from 43894 using the plasmid incompatibility method did not induce Gad overexpression as shown in 277. Taken together, the results suggest that variation in acid resistance among EHEC isolates exists, and the large virulence plasmid pO157 has no effect on weak acid resistance phenotype displayed in 43894.
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Affiliation(s)
- Seon Mi Wi
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Se Kye Kim
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jun Bong Lee
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Jang Won Yoon
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea.
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Zhao F, Ding G, Wang Q, Du H, Xiao G, Zhou D. Deletion of the waaf gene affects O antigen synthesis and pathogenicity in Vibrio parahaemolyticus from shellfish. FOOD SCIENCE AND HUMAN WELLNESS 2022. [DOI: 10.1016/j.fshw.2021.11.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Kuo CJ, Chen JW, Chiu HC, Teng CH, Hsu TI, Lu PJ, Syu WJ, Wang ST, Chou TC, Chen CS. Mutation of the Enterohemorrhagic Escherichia coli Core LPS Biosynthesis Enzyme RfaD Confers Hypersusceptibility to Host Intestinal Innate Immunity In vivo. Front Cell Infect Microbiol 2016; 6:82. [PMID: 27570746 PMCID: PMC4982379 DOI: 10.3389/fcimb.2016.00082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/02/2016] [Indexed: 11/13/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is an important foodborne pathogen causing severe diseases in humans worldwide. Currently, there is no specific treatment available for EHEC infection and the use of conventional antibiotics is contraindicated. Therefore, identification of potential therapeutic targets and development of effective measures to control and treat EHEC infection are needed. Lipopolysaccharides (LPS) are surface glycolipids found on the outer membrane of gram-negative bacteria, including EHEC, and LPS biosynthesis has long been considered as potential anti-bacterial target. Here, we demonstrated that the EHEC rfaD gene that functions in the biosynthesis of the LPS inner core is required for the intestinal colonization and pathogenesis of EHEC in vivo. Disruption of the EHEC rfaD confers attenuated toxicity in Caenorhabditis elegans and less bacterial colonization in the intestine of C. elegans and mouse. Moreover, rfaD is also involved in the control of susceptibility of EHEC to antimicrobial peptides and host intestinal immunity. It is worth noting that rfaD mutation did not interfere with the growth kinetics when compared to the wild-type EHEC cells. Taken together, we demonstrated that mutations of the EHEC rfaD confer hypersusceptibility to host intestinal innate immunity in vivo, and suggested that targeting the RfaD or the core LPS synthesis pathway may provide alternative therapeutic regimens for EHEC infection.
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Affiliation(s)
- Cheng-Ju Kuo
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Jenn-Wei Chen
- Center of Infectious Disease and Signaling Research, National Cheng Kung UniversityTainan, Taiwan
| | - Hao-Chieh Chiu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan UniversityTaipei, Taiwan
| | - Ching-Hao Teng
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Tai-I Hsu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Pei-Jung Lu
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Wan-Jr Syu
- Institute of Microbiology and Immunology, National Yang Ming UniversityTaipei, Taiwan
| | - Sin-Tian Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Ting-Chen Chou
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
| | - Chang-Shi Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung UniversityTainan, Taiwan
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Jiang HY, Zhao N, Zhang QL, Gao JM, Liu LL, Wu TF, Wang Y, Huang QH, Gou Q, Chen W, Gong PT, Li JH, Gao YJ, Liu B, Zhang XC. Intestinal microbes influence the survival, reproduction and protein profile of Trichinella spiralis in vitro. Int J Parasitol 2015; 46:51-8. [PMID: 26432293 DOI: 10.1016/j.ijpara.2015.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/21/2015] [Accepted: 08/24/2015] [Indexed: 12/21/2022]
Abstract
The interactions between intestinal microbes and parasitic worms play an essential role in the development of the host immune system. However, the effects of gut microbes on Trichinella spiralis are unknown. The aim of this work was to explore microbe-induced alterations in the survival and reproduction of T. spiralis in vitro. To further identify the proteins and genes involved in the response of nematodes to microbes, quantitative proteomic analysis of T. spiralis was conducted by iTRAQ-coupled LCMS/MS technology and quantitative real-time-PCR was used to measure changes in mRNA expression. The results showed Lactobacillus acidophilus, and especially Lactobacillus bulgaricus, significantly enhanced the survival and reproductive rates of nematodes. Salmonella enterica, and especially Escherichia coli O157:H7 (EHEC), had opposite effects. Genetic responses were activated mainly by EHEC. A total of 514 proteins were identified and quantified, and carbohydrate metabolism-related proteins existed in a higher proportion. These findings indicated that some gut bacteria are friendly or harmful to humans and in addition they may have similar beneficial or detrimental effects on parasites. This may be due to the regulation of expression of specific genes and proteins. Our studies provide a basis for developing therapies against parasitic infections from knowledge generated by studying the gut microbes of mammals.
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Affiliation(s)
- Hai-yan Jiang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Na Zhao
- Laboratory Animal Center, North China University of Science and Technology, Tangshan, China
| | - Qiao-ling Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jiang-ming Gao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Li-li Liu
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Teng-Fei Wu
- Laboratory Animal Center, China Medical University, Shenyang, China
| | - Ying Wang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Qing-hua Huang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Qiang Gou
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Wei Chen
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Peng-tao Gong
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jian-hua Li
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Ying-jie Gao
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Bo Liu
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China; Institute of Zoonosis, Jilin University, Changchun, China.
| | - Xi-chen Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China.
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The waaL gene is involved in lipopolysaccharide synthesis and plays a role on the bacterial pathogenesis of avian pathogenic Escherichia coli. Vet Microbiol 2014; 172:486-91. [PMID: 24970366 DOI: 10.1016/j.vetmic.2014.05.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/27/2014] [Accepted: 05/29/2014] [Indexed: 11/23/2022]
Abstract
Avian pathogenic Escherichia coli (APEC) is a Gram-negative bacterium that causes avian colibacillosis, resulting in economically devastating to poultry industries worldwide. Lipopolysaccharide (LPS) has been identified as an important virulence factor of E. coli. The waaL gene encodes O-antigen ligase, which is responsible for attaching the O-antigen to lipid A-core oligosaccharide. In this study, a mutant strain ΔwaaL was constructed from APEC serotype 2 strain DE17. The mutant strain showed a decreased swimming motility and resistance to complement-mediated killing but a similar growth rate in the culture, compared with its parent strain. In addition, the mutant LPS demonstrated different patterns in SDS-PAGE followed by silver staining and western blotting. Besides, the mutant strain significantly decreased its adherence and invasion abilities to DF-1 cells, compared to its parent strain DE17. Deletion of the waaL gene in DE17 reduced the bacterial virulence by 42.2-fold in ducklings, based on measurement of the median lethal dose (LD50). Additional analysis indicated that deletion of the waaL gene increased the biofilm formation ability and reduced the resistance to environmental stress. These results suggest that the waaL gene functions on the APEC LPS synthesis and bacterial pathogenesis.
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