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Meng X, He M, Xia P, Wang J, Wang H, Zhu G. Functions of Small Non-Coding RNAs in Salmonella–Host Interactions. BIOLOGY 2022; 11:biology11091283. [PMID: 36138763 PMCID: PMC9495376 DOI: 10.3390/biology11091283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/18/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary In the process of infecting the host, Salmonella senses and adapts to the environment within the host, breaks through the host’s defense system, and survives and multiplies in the host cell. As a class of universal regulators encoded in intergenic space, an increasing number of small non-coding RNAs (sRNAs) have been found to be involved in a series of processes during Salmonella infection, and they play an important role in interactions with the host cell. In this review, we discuss how sRNAs help Salmonella resist acidic environmental stress by regulating acid resistance genes and modulate adhesion and invasion to non-phagocytic cells by regulating virulent genes such as fimbrial subunits and outer membrane proteins. In addition, sRNAs help Salmonella adapt to oxidative stress within host cells and promote survival within macrophages. Although the function of a variety of sRNAs has been studied during host–Salmonella interactions, many of sRNAs’ functions remain to be discovered. Abstract Salmonella species infect hosts by entering phagocytic and non-phagocytic cells, causing diverse disease symptoms, such as fever, gastroenteritis, and even death. Therefore, Salmonella has attracted much attention. Many factors are involved in pathogenesis, for example, the capsule, enterotoxins, Salmonella pathogenicity islands (SPIs), and corresponding regulators. These factors are all traditional proteins associated with virulence and regulation. Recently, small non-coding RNAs (sRNAs) have also been reported to function as critical regulators. Salmonella has become a model organism for studying sRNAs. sRNAs regulate gene expression by imperfect base-pairing with targets at the post-transcriptional level. sRNAs are involved in diverse biological processes, such as virulence, substance metabolism, and adaptation to stress environments. Although some studies have reported the crucial roles of sRNAs in regulating host–pathogen interactions, the function of sRNAs in host–Salmonella interactions has rarely been reviewed. Here, we review the functions of sRNAs during the infection of host cells by Salmonella, aiming to deepen our understanding of sRNA functions and the pathogenic mechanism of Salmonella.
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Affiliation(s)
- Xia Meng
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Prevention and Control of Important Animal infectious Diseases and Zoonotic Diseases of China, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China
- Correspondence:
| | - Mengping He
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Prevention and Control of Important Animal infectious Diseases and Zoonotic Diseases of China, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China
| | - Pengpeng Xia
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Prevention and Control of Important Animal infectious Diseases and Zoonotic Diseases of China, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China
| | - Jinqiu Wang
- Department of Animal Husbandry and Veterinary Medicine, Beijing Agricultural Vocational College, Beijing 102442, China
| | - Heng Wang
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Prevention and Control of Important Animal infectious Diseases and Zoonotic Diseases of China, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China
| | - Guoqiang Zhu
- Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Prevention and Control of Important Animal infectious Diseases and Zoonotic Diseases of China, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China
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Ferelli AMC, Bolten S, Szczesny B, Micallef SA. Salmonella enterica Elicits and Is Restricted by Nitric Oxide and Reactive Oxygen Species on Tomato. Front Microbiol 2020; 11:391. [PMID: 32231649 PMCID: PMC7082413 DOI: 10.3389/fmicb.2020.00391] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/25/2020] [Indexed: 11/17/2022] Open
Abstract
The enteric pathogen Salmonella enterica can interact with parts of the plant immune system despite not being a phytopathogen. Previous transcriptomic profiling of S. enterica associating with tomato suggested that Salmonella was responding to oxidative and nitrosative stress in the plant niche. We aimed to investigate whether Salmonella was eliciting generation of reactive oxygen species (ROS) and nitric oxide (NO), two components of the microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) of plants. We also sought to determine whether this interaction had any measurable effects on Salmonella colonization of plants. Biochemical, gene expression and on-plant challenge assays of tomato vegetative and fruit organs were conducted to assess the elicitation of ROS and NO in response to Salmonella Newport association. The counter bacterial response and the effect of NO and ROS on Salmonella colonization was also investigated. We detected H2O2 in leaves and fruit following challenge with live S. Newport (p < 0.05). Conversely, NO was detected on leaves but not on fruit in response to S. Newport (p < 0.05). We found no evidence of plant defense attenuation by live S. Newport. Bacterial gene expression of S. Newport associating with leaves and fruit were indicative of adaptation to biotic stress in the plant niche. The nitrosative stress response genes hmpA and yoaG were significantly up-regulated in S. Newport on leaves and fruit tissue compared to tissue scavenged of NO or ROS (p < 0.05). Chemical modulation of these molecules in the plant had a restrictive effect on bacterial populations. Significantly higher S. Newport titers were retrieved from H2O2 scavenged leaves and fruit surfaces compared to controls (p < 0.05). Similarly, S. Newport counts recovered from NO-scavenged leaves, but not fruit, were higher compared to control (p < 0.05), and significantly lower on leaves pre-elicited to produce endogenous NO. We present evidence of Salmonella elicitation of ROS and NO in tomato, which appear to have a restricting effect on the pathogen. Moreover, bacterial recognition of ROS and NO stress was detected. This work shows that tomato has mechanisms to restrict Salmonella populations and ROS and NO detoxification may play an important role in Salmonella adaptation to the plant niche.
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Affiliation(s)
- Angela Marie C Ferelli
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Samantha Bolten
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Brooke Szczesny
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Shirley A Micallef
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States.,Centre for Food Safety and Security Systems, University of Maryland, College Park, MD, United States
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Azimi T, Zamirnasta M, Sani MA, Soltan Dallal MM, Nasser A. Molecular Mechanisms of Salmonella Effector Proteins: A Comprehensive Review. Infect Drug Resist 2020; 13:11-26. [PMID: 32021316 PMCID: PMC6954085 DOI: 10.2147/idr.s230604] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 12/20/2019] [Indexed: 12/27/2022] Open
Abstract
Salmonella can be categorized into many serotypes, which are specific to known hosts or broadhosts. It makes no difference which one of the serotypes would penetrate the gastrointestinal tract because they all face similar obstacles such as mucus and microbiome. However, following their penetration, some species remain in the gastrointestinal tract; yet, others spread to another organ like gallbladder. Salmonella is required to alter the immune response to sustain its intracellular life. Changing the host response requires particular effector proteins and vehicles to translocate them. To this end, a categorized gene called Salmonella pathogenicity island (SPI) was developed; genes like Salmonella pathogenicity island encode aggressive or modulating proteins. Initially, Salmonella needs to be attached and stabilized via adhesin factor, without which no further steps can be taken. In this review, an attempt has been made to elaborate on each factor attached to the host cell or to modulating and aggressive proteins that evade immune systems. This review includes four sections: (A) attachment factors or T3SS- independent entrance, (B) effector proteins or T3SS-dependent entrance, (c) regulation of invasive genes, and (D) regulation of immune responses.
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Affiliation(s)
- Taher Azimi
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Students Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Zamirnasta
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
| | - Mahmood Alizadeh Sani
- Food Safety and Hygiene Division, Environmental health Department, School of Public Health, Tehran University of medical sciences, Tehran, Iran
- Students Research Committee, Department of Food Sciences and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Ahmad Nasser
- Clinical Microbiology Research Center, Ilam University of Medical Science, Ilam, Iran
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Department of Medical Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran
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Mechesso AF, Quah Y, Park SC. Ginsenoside Rg3 reduces the adhesion, invasion, and intracellular survival of Salmonella enterica serovar Typhimurium. J Ginseng Res 2019; 45:75-85. [PMID: 33437159 PMCID: PMC7790883 DOI: 10.1016/j.jgr.2019.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/08/2019] [Accepted: 09/17/2019] [Indexed: 11/28/2022] Open
Abstract
Background Invasive infections due to foodborne pathogens, including Salmonella enterica serovar Typhimurium, are prevalent and life-threatening. This study aimed to evaluate the effects of ginsenoside Rg3 (Rg3) on the adhesion, invasion, and intracellular survival of S. Typhimurium. Methods The impacts of Rg3 on bacterial growth and host cell viability were determined using the time kill and the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays, respectively. Gentamicin assay and confocal microscopic examination were undertaken to determine the effects of Rg3 on the adhesive and invasive abilities of S. Typhimurium to Caco-2 and RAW 264.7 cells. Quantitative reverse transcription polymerase chain reaction was performed to assess the expression of genes correlated with the adhesion, invasion, and virulence of S. Typhimurium. Results Subinhibitory concentrations of Rg3 significantly reduced (p < 0.05) the adhesion, invasion, and intracellular survival of S. Typhimurium. Rg3 considerably reduced (p < 0.05) the bacterial motility as well as the release of nitrite from infected macrophages in a concentration-dependent manner. The expression of genes related to the adhesion, invasion, quorum sensing, and virulence of S. Typhimurium including cheY, hilA, OmpD, PrgK, rsgE, SdiA, and SipB was significantly reduced after Rg3 treatment. Besides, the compound downregulated rac-1 and Cdc-42 that are essential for actin remodeling and membrane ruffling, thereby facilitating Salmonella entry into host cells. This report is the first to describe the effects of Rg3 on "trigger" entry mechanism and intracellular survival S. Typhimurium. Conclusion Rg3 could be considered as a supplement agent to prevent S. Typhimurium infection.
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Affiliation(s)
- Abraham F Mechesso
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Yixian Quah
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Seung-Chun Park
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Daegu, Republic of Korea
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Birhanu BT, Park NH, Lee SJ, Hossain MA, Park SC. Inhibition of Salmonella Typhimurium adhesion, invasion, and intracellular survival via treatment with methyl gallate alone and in combination with marbofloxacin. Vet Res 2018; 49:101. [PMID: 30286813 PMCID: PMC6389159 DOI: 10.1186/s13567-018-0597-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 09/23/2018] [Indexed: 12/19/2022] Open
Abstract
Salmonella enterica serovar Typhimurium infects intestinal epithelia and macrophages, which is prevented by inhibiting adhesion and cell invasion. This study aimed to investigate the role of methyl gallate (MG) in adhesion, invasion, and intracellular survival of Salmonella Typhimurium in Caco-2 and RAW 264.7 cells via a gentamicin protection assay, confocal microscopy, and quantitative reverse-transcription polymerase chain reaction. MG (30 µg/mL) inhibited adhesion and invasion of Salmonella Typhimurium by 54.01% and 60.5% in RAW 264.7 cells, respectively. The combination of MG with sub-minimum inhibitory concentration (MIC) of marbofloxacin (MRB) inhibited the adhesion, invasion, and intracellular survival by 70.49%, 67.36%, and 74%, respectively. Confocal microscopy further revealed reductions in bacterial count in Caco-2 cells treated with MG alone or with sub-MIC of MRB. Furthermore, MG alone or in combination with sub-MIC of MRB decreased the motility of Salmonella Typhimurium. Quorum sensing genes including sdiA, srgE, and rck were downregulated by 52.8%, 61.7%, and 22.2%, respectively. Moreover, rac-1 was downregulated by 56.9% and 71.9% for MG alone and combined with sub-MIC of MRB, respectively, in mammalian cells. Furthermore, MG downregulated virulence genes of Salmonella Typhimurium including cheY, ompD, sipB, lexA, and ompF by 59.6%, 60.2%, 20.5%, 31.4%, and 16.2%, respectively. Together, the present results indicate that MG alone or in combination with a sub-MIC of MRB effectively inhibited the adhesion, invasion, and intracellular survival of Salmonella Typhimurium in vitro by downregulating quorum sensing and virulence genes.
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Affiliation(s)
- Biruk Tesfaye Birhanu
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Bukgu, Daegu, 41566, South Korea
| | - Na-Hye Park
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Bukgu, Daegu, 41566, South Korea
| | - Seung-Jin Lee
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Bukgu, Daegu, 41566, South Korea
| | - Md Akil Hossain
- Veterinary Drugs and Biologics Division, Animal and Plant Quarantine Agency, Gimcheon, 39660, South Korea
| | - Seung-Chun Park
- Laboratory of Veterinary Pharmacokinetics and Pharmacodynamics, College of Veterinary Medicine, Kyungpook National University, Bukgu, Daegu, 41566, South Korea.
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Byvalov AA, Konyshev IV, Novikova OD, Portnyagina OY, Belozerov VS, Khomenko VA, Davydova VN. The Adhesiveness of the OmpF and OmpC Porins from Yersinia pseudotuberculosis to J774 Macrophages. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918050068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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de Almeida FA, Pimentel-Filho NDJ, Carrijo LC, Bento CBP, Baracat-Pereira MC, Pinto UM, de Oliveira LL, Vanetti MCD. Acyl homoserine lactone changes the abundance of proteins and the levels of organic acids associated with stationary phase in Salmonella Enteritidis. Microb Pathog 2017; 102:148-159. [DOI: 10.1016/j.micpath.2016.11.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/22/2016] [Accepted: 11/29/2016] [Indexed: 11/25/2022]
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Chaurasia S, Shasany AK, Aggarwal A, Misra R. Recombinant Salmonella typhimurium outer membrane protein A is recognized by synovial fluid CD8 cells and stimulates synovial fluid mononuclear cells to produce interleukin (IL)-17/IL-23 in patients with reactive arthritis and undifferentiated spondyloarthropathy. Clin Exp Immunol 2016; 185:210-8. [PMID: 27060348 DOI: 10.1111/cei.12799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/03/2016] [Accepted: 04/04/2016] [Indexed: 01/21/2023] Open
Abstract
In developing countries, one-third of patients with reactive arthritis (ReA) and undifferentiated spondyloarthropathy (uSpA) are triggered by Salmonella typhimurium. Synovial fluid mononuclear cells (SFMCs) of patients with ReA and uSpA proliferate to low molecular weight fractions (lmwf) of outer membrane proteins (Omp) of S. typhimurium. To characterize further the immunity of Omp of Salmonella, cellular immune response to two recombinant proteins of lmwf, OmpA and OmpD of S. typhimurium (rOmpA/D-sal) was assessed in 30 patients with ReA/uSpA. Using flow cytometry, 17 of 30 patients' SF CD8(+) T cells showed significant intracellular interferon (IFN)-γ to Omp crude lysate of S. typhimurium. Of these 17, 11 showed significantly more CD8(+) CD69(+) IFN-γ T cells to rOmpA-sal, whereas only four showed reactivity to rOmpD-sal. The mean stimulation index was significantly greater in rOmpA-sal than rOmpD-sal [3·0 (1·5-6·5) versus 1·5 (1·0-2·75), P < 0·005]. Similarly, using enzyme-linked immunospot (ELISPOT) in these 17 patients, the mean spots of IFN-γ-producing SFMCs were significantly greater in rOmpA-sal than rOmpD-sal [44·9 (3·5-130·7) versus 19·25 (6-41), P < 0·05]. SFMCs stimulated by rOmpA-sal produced significantly more proinflammatory cytokines than rOmpD-sal: IFN-γ [1·44 (0·39-20·42) versus 0·72 (0·048-9·15) ng/ml, P < 0·05], interleukin (IL)-17 [28·60 (6·15-510·86) versus 11·84 (6·83-252·62) pg/ml, P < 0·05], IL-23 [70·19 (15-1161·16) versus 28·25 (> 15-241·52) pg/ml, P < 0·05] and IL-6 [59·78 (2·03-273·36) versus 10·17 (0·004-190·19) ng/ml, P < 0·05]. The rOmpA-sal-specific CD8(+) T cell response correlated with duration of current synovitis (r = 0·53, P < 0·05). Thus, OmpA of S. typhimurium is a target of SF CD8(+) T cells and drives SFMC to produce increased cytokines of the IL-17/IL-23 axis which contribute to the pathogenesis of Salmonella-triggered ReA.
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Affiliation(s)
- S Chaurasia
- Department of Clinical Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences
| | - A K Shasany
- Biotechnology Division, Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - A Aggarwal
- Department of Clinical Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences
| | - R Misra
- Department of Clinical Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences
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Ipinza F, Collao B, Monsalva D, Bustamante VH, Luraschi R, Alegría-Arcos M, Almonacid DE, Aguayo D, Calderón IL, Gil F, Santiviago CA, Morales EH, Calva E, Saavedra CP. Participation of the Salmonella OmpD porin in the infection of RAW264.7 macrophages and BALB/c mice. PLoS One 2014; 9:e111062. [PMID: 25360745 PMCID: PMC4215857 DOI: 10.1371/journal.pone.0111062] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 09/21/2014] [Indexed: 11/18/2022] Open
Abstract
Salmonella Typhimurium is the etiological agent of gastroenteritis in humans and enteric fever in mice. Inside these hosts, Salmonella must overcome hostile conditions to develop a successful infection, a process in which the levels of porins may be critical. Herein, the role of the Salmonella Typhimurium porin OmpD in the infection process was assessed for adherence, invasion and proliferation in RAW264.7 mouse macrophages and in BALB/c mice. In cultured macrophages, a ΔompD strain exhibited increased invasion and proliferation phenotypes as compared to its parental strain. In contrast, overexpression of ompD caused a reduction in bacterial proliferation but did not affect adherence or invasion. In the murine model, the ΔompD strain showed increased ability to survive and replicate in target organs of infection. The ompD transcript levels showed a down-regulation when Salmonella resided within cultured macrophages and when it colonized target organs in infected mice. Additionally, cultured macrophages infected with the ΔompD strain produced lower levels of reactive oxygen species, suggesting that down-regulation of ompD could favor replication of Salmonella inside macrophages and the subsequent systemic dissemination, by limiting the reactive oxygen species response of the host.
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Affiliation(s)
- Francisco Ipinza
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Bernardo Collao
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Debbie Monsalva
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Victor H. Bustamante
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Roberto Luraschi
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Melissa Alegría-Arcos
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
| | - Daniel E. Almonacid
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
| | - Daniel Aguayo
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile
| | - Iván L. Calderón
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Fernando Gil
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
| | - Carlos A. Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Eduardo H. Morales
- Great Lakes Bioenergy Research Center and Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Edmundo Calva
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Claudia P. Saavedra
- Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile
- * E-mail:
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Applications of flow cytometry to characterize bacterial physiological responses. BIOMED RESEARCH INTERNATIONAL 2014; 2014:461941. [PMID: 25276788 PMCID: PMC4174974 DOI: 10.1155/2014/461941] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 12/30/2022]
Abstract
Although reports of flow cytometry (FCM) applied to bacterial analysis are increasing, studies of FCM related to human cells still vastly outnumber other reports. However, current advances in FCM combined with a new generation of cellular reporter probes have made this technique suitable for analyzing physiological responses in bacteria. We review how FCM has been applied to characterize distinct physiological conditions in bacteria including responses to antibiotics and other cytotoxic chemicals and physical factors, pathogen-host interactions, cell differentiation during biofilm formation, and the mechanisms governing development pathways such as sporulation. Since FCM is suitable for performing studies at the single-cell level, we describe how this powerful technique has yielded invaluable information about the heterogeneous distribution of differently and even specialized responding cells and how it may help to provide insights about how cell interaction takes place in complex structures, such as those that prevail in bacterial biofilms.
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Yang Y, Wan C, Xu H, Aguilar ZP, Tan Q, Xu F, Lai W, Xiong Y, Wei H. Identification of an outer membrane protein of Salmonella enterica serovar Typhimurium as a potential vaccine candidate for Salmonellosis in mice. Microbes Infect 2013; 15:388-98. [PMID: 23485513 DOI: 10.1016/j.micinf.2013.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 02/10/2013] [Accepted: 02/18/2013] [Indexed: 12/27/2022]
Abstract
We report our investigation of the functions of PagN in Salmonella pathogenesis and its potential as a vaccine candidate. Further investigation conducted in this study indicates that the outer membrane protein PagN is important for Salmonella adhesion/invasion of epithelial cells as well as bacterial virulence. When pagN was deleted from Salmonella enterica serovar Typhimurium (S. Typhimurium), the adhesion and invasion of HT-29 epithelial cells was significantly decreased compared with the wild type strain. Mice infected with the pagN mutant strain exhibited less pathological signs in the intestine and survived longer than the wild-type-infected mice. PagN is widely distributed and conserved among clinical isolates of different Salmonella serovars, making PagN a potential vaccine candidate for Salmonella infection. To elucidate the potential of PagN as a vaccine, we expressed and purified recombinant PagN (rPagN). When rPagN was tested in mice, it provided significant protection against Salmonella infection in vivo. In vitro, anti-PagN serum enhanced clearance of Salmonella, indicating a contribution of PagN-specific antibodies to the killing process. This correlates well with the observed protection of mice immunized with rPagN. Our preliminary results indicate more functions of PagN in S. Typhimurium virulence as well as its potential as a protective vaccine.
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Affiliation(s)
- Youjun Yang
- State Key Laboratory of Food Science and Technology, Nanchang University, 235 Nanjing East Road, Nanchang 330047, PR China
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Ramachandran VK, Shearer N, Jacob JJ, Sharma CM, Thompson A. The architecture and ppGpp-dependent expression of the primary transcriptome of Salmonella Typhimurium during invasion gene expression. BMC Genomics 2012; 13:25. [PMID: 22251276 PMCID: PMC3293720 DOI: 10.1186/1471-2164-13-25] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 01/17/2012] [Indexed: 11/26/2022] Open
Abstract
Background Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium (S. Typhimurium) requires expression of the extracellular virulence gene expression programme (STEX), activation of which is dependent on the signalling molecule guanosine tetraphosphate (ppGpp). Recently, next-generation transcriptomics (RNA-seq) has revealed the unexpected complexity of bacterial transcriptomes and in this report we use differential RNA sequencing (dRNA-seq) to define the high-resolution transcriptomic architecture of wild-type S. Typhimurium and a ppGpp null strain under growth conditions which model STEX. In doing so we show that ppGpp plays a much wider role in regulating the S. Typhimurium STEX primary transcriptome than previously recognised. Results Here we report the precise mapping of transcriptional start sites (TSSs) for 78% of the S. Typhimurium open reading frames (ORFs). The TSS mapping enabled a genome-wide promoter analysis resulting in the prediction of 169 alternative sigma factor binding sites, and the prediction of the structure of 625 operons. We also report the discovery of 55 new candidate small RNAs (sRNAs) and 302 candidate antisense RNAs (asRNAs). We discovered 32 ppGpp-dependent alternative TSSs and determined the extent and level of ppGpp-dependent coding and non-coding transcription. We found that 34% and 20% of coding and non-coding RNA transcription respectively was ppGpp-dependent under these growth conditions, adding a further dimension to the role of this remarkable small regulatory molecule in enabling rapid adaptation to the infective environment. Conclusions The transcriptional architecture of S. Typhimurium and finer definition of the key role ppGpp plays in regulating Salmonella coding and non-coding transcription should promote the understanding of gene regulation in this important food borne pathogen and act as a resource for future research.
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Affiliation(s)
- Vinoy K Ramachandran
- Institute of Food Research, Norwich, UK, University of Würzburg, Josef-Schneider-Str, 2/Bau D15, 97080 Würzburg, Germany
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Membrane efflux and influx modulate both multidrug resistance and virulence of Klebsiella pneumoniae in a Caenorhabditis elegans model. Antimicrob Agents Chemother 2010; 54:4373-8. [PMID: 20679507 DOI: 10.1128/aac.01607-09] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Cross-resistance to cefoxitin (FOX), chloramphenicol (CMP), and quinolones (nalidixic acid [NAL]) related to a putative efflux system overexpression has recently been reported for Klebsiella pneumoniae. The potential impact of this multidrug resistance (MDR) on the virulence of K. pneumoniae was evaluated in the Caenorhabditis elegans model. For 2 of the 3 MDR clinical isolates studied, a significant increase in acrB transcription was found in comparison with their antibiotic-susceptible revertants. ATCC 138821 and MDR, revertant, and derivative strains with altered porin expression were studied. Strains proved or suspected to overexpress an efflux system were significantly more virulent than the ATCC and revertant strains (time to kill 50% of nematodes [LT(50)] in days: 3.4 to 3.8 ± 0.2 versus 4.1 to 4.4 ± 0.3, P < 0.001). Inversely, strains with altered porin expression were significantly less virulent, independently of the expression level of efflux system (LT(50) = 5.4 to 5.6 ± 0.2, P < 0.001). Altered porin expression did not change MICs of CMP and NAL but did those of FOX (4 to 16× MIC) and ertapenem (16 to 64× MIC). The strains with a normally or an overexpressed efflux system that received the β-lactamase CTX-M-15 became more widely resistant without modification of their virulence potential, suggesting that balance between resistance and virulence is dependent on the type of resistance mechanisms. In conclusion, this study shows that the expression of both efflux systems and porins is a key factor not only for antibiotic resistance but also virulence potential in K. pneumoniae.
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Lambert MA, Smith SGJ. The PagN protein mediates invasion via interaction with proteoglycan. FEMS Microbiol Lett 2009; 297:209-16. [PMID: 19552707 DOI: 10.1111/j.1574-6968.2009.01666.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Heparan sulphate proteoglycans are major components of the mammalian cell membrane. Here we show that PagN of Salmonella enterica serovar Typhimurium utilizes heparinated proteoglycan to successfully invade mammalian cells. Mutants defective in the production of the outer membrane protein PagN displayed similar levels of invasiveness of glycosylation-deficient pgsA-745 cells in comparison with wild-type Salmonella. Furthermore, pgsA-745 cells were invaded c. 400-fold less efficiently than CHO-K1 cells by Escherichia coli expressing PagN. PagN is likely to interact with heparinated proteoglycan as heparin could inhibit PagN-mediated invasion in a dose-dependent manner. Finally, we show, by deletion analysis, that all four extracellular loops of PagN are crucial for invasion of mammalian cells.
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Lambert MA, Smith SGJ. The PagN protein of Salmonella enterica serovar Typhimurium is an adhesin and invasin. BMC Microbiol 2008; 8:142. [PMID: 18778463 PMCID: PMC2553418 DOI: 10.1186/1471-2180-8-142] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Accepted: 09/08/2008] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The pagN gene of Salmonella enterica serovar Typhimurium is a PhoP-regulated gene that is up-regulated during growth within macrophages and in vivo in murine models of infection. The PagN protein displays similarity to the Hek and Tia invasins/adhesins of Escherichia coli. Thus far no function has been ascribed to the PagN protein. RESULTS Here we show that the outer membrane located PagN protein mediates agglutination of red blood cells and that this can be masked by LPS. When expressed in Escherichia coli the PagN protein supports adhesion to and invasion of mammalian cells in a manner that is dependent on cytoskeletal rearrangements. S. enterica sv Typhimurium pagN mutants display a reduction in adhesion to and invasion of epithelial cells. Finally, we demonstrate that over-expression of PagN in a SPI-1 mutant can partially compensate for the lack of a functional invasasome. CONCLUSION PagN is an outer membrane protein that may contribute to the virulence of S. Typhimurium. This protein is a haemagglutinin and contributes to the adherence to mammalian cells. In addition, PagN can mediate high-level invasion of CHO-K1 cells. Previously,pagN mutants have been shown to be less competitive in vivo and thus this may be due to their lessened ability to interact with mammalian cells. Finally PagN can be added to an ever-growing repertoire of factors that contribute to the pathogenesis of Salmonella.
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Affiliation(s)
- Matthew A Lambert
- Department of Clinical Microbiology, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland.
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Subramanian K, Shankar RB, Meenakshisundaram S, Lakshmi BS, Williams PH, Balakrishnan A. LamB-mediated adherence of enteropathogenic Escherichia coli to HEp-2 cells. J Appl Microbiol 2008; 105:715-22. [PMID: 18397259 DOI: 10.1111/j.1365-2672.2008.03800.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To establish the role of maltoporin (LamB) in adherence of enteropathogenic Escherichia coli (EPEC) to epithelial cells in vitro. METHODS AND RESULTS Three strains, wild type (WT) EPEC, a maltoporin (LamB) mutant DeltalamB, and DH5alpha were used to study adherence to cultured HEp-2 cells. Mutant DeltalamB was found to be deficient in adherence compared to WT EPEC. Adherence of DeltalamB was restored to wild type levels when complemented with the cloned lamB gene. The non-adherent strain DH5alpha also adhered to HEp-2 cells when it harboured the cloned lamB gene. The LamB protein was isolated from WT EPEC by electroelution and antibodies were raised in rabbits. The specificity of the antibodies was analysed by Western blotting. Anti-LamB antiserum reduced adherence of WT EPEC to HEp-2 cells. The LamB protein was coated on latex beads and the beads adhered to HEp-2 cells. Anti-LamB antiserum prevented bead adherence to HEp-2 cells. Multiple sequence alignment showed that the L9 loop of EPEC LamB had four amino acids different from the L9 loop of LamB from several other related pathogens. CONCLUSIONS LamB serves as an alternative or additional adherence factor for EPEC. SIGNIFICANCE AND IMPACT OF THE STUDY Adherence is an important component of the pathogenesis of noninvasive pathogens like EPEC. A putative adhesin such as LamB, which has already been found to be co-expressed with virulence factor EspB may be a potential vaccine candidate for control of EPEC and related pathogens.
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Affiliation(s)
- K Subramanian
- Centre for Biotechnology, Anna University, Chennai, India
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Pfeiffer V, Sittka A, Tomer R, Tedin K, Brinkmann V, Vogel J. A small non-coding RNA of the invasion gene island (SPI-1) represses outer membrane protein synthesis from the Salmonella core genome. Mol Microbiol 2007; 66:1174-91. [PMID: 17971080 DOI: 10.1111/j.1365-2958.2007.05991.x] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The Salmonella pathogenicity island (SPI-1) encodes approximately 35 proteins involved in assembly of a type III secretion system (T3SS) which endows Salmonella with the ability to invade eukaryotic cells. We have discovered a novel SPI-1 gene, invR, which expresses an abundant small non-coding RNA (sRNA). The invR gene, which we identified in a global search for new Salmonella sRNA genes, is activated by the major SPI-1 transcription factor, HilD, under conditions that favour host cell invasion. The RNA chaperone, Hfq, is essential for the in vivo stability of the approximately 80 nt InvR RNA. Hfq binds InvR with high affinity in vitro, and InvR co-immunoprecipitates with FLAG epitope-tagged Hfq in Salmonella extracts. Surprisingly, deletion/overexpression of invR revealed no phenotype in SPI-1 regulation. In contrast, we find that InvR represses the synthesis of the abundant OmpD porin encoded by the Salmonella core genome. As invR is conserved in the early branching Salmonella bongori, we speculate that porin repression by InvR may have aided successful establishment of the SPI-1 T3SS after horizontal acquisition in the Salmonella lineage. This study identifies the first regulatory RNA of an enterobacterial pathogenicity island, and new roles for Hfq and HilD in SPI-1 gene expression.
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Affiliation(s)
- Verena Pfeiffer
- Max Planck Institute for Infection Biology, Charitéplatz 1, D-10117 Berlin, Germany
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Rolhion N, Carvalho FA, Darfeuille-Michaud A. OmpC and the sigma(E) regulatory pathway are involved in adhesion and invasion of the Crohn's disease-associated Escherichia coli strain LF82. Mol Microbiol 2007; 63:1684-700. [PMID: 17367388 DOI: 10.1111/j.1365-2958.2007.05638.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Ileal lesions of 36.4% of patients with Crohn's disease (CD), an inflammatory bowel disease in humans, are colonized by pathogenic adherent-invasive Escherichia coli (AIEC), and high levels of antibodies directed against E. coli OmpC are present in 37-55% of CD patients. We therefore investigated the expression of OmpC and its role in the interaction of CD-associated adherent-invasive E. coli strain LF82 with intestinal epithelial cells. High osmolarity induced a significant increase in the ability of LF82 bacteria to interact with Intestine-407 cells, which correlates with increased OmpC expression. Deletion of ompC gene markedly decreased the adhesion and invasion levels of the corresponding mutant. A LF82-DeltaompR mutant impaired in OmpC and OmpF expression, showed decreased adhesion and invasion, and unlike a K-12-negative OmpR mutant did not express flagella and type 1 pili. Interestingly, the wild-type phenotype was restored when OmpC or OmpF expression was induced in the LF82-DeltaompR mutant. Overexpression of RpoE in the LF82-DeltaompR isogenic mutant restored a full wild-type phenotype without restoring OmpC expression. Increased expression of RpoE was observed in wild-type strain LF82 at high osmolarity. Hence, the role of OmpC in the AIEC LF82 adhesion and invasion is indirect and involves the sigma(E) regulatory pathway.
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Affiliation(s)
- Nathalie Rolhion
- Univ Clermont 1, Pathogénie Bactérienne Intestinale, USC INRA 2018, Clermont-Ferrand F-63000, France
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Hara-Kaonga B, Pistole TG. A dual fluorescence flow cytometric analysis of bacterial adherence to mammalian host cells. J Microbiol Methods 2007; 69:37-43. [PMID: 17222473 PMCID: PMC2649669 DOI: 10.1016/j.mimet.2006.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 11/20/2006] [Accepted: 11/22/2006] [Indexed: 11/30/2022]
Abstract
Flow cytometry has provided a powerful tool for analyzing bacteria-host cell associations. Established approaches have used bacteria, labeled either directly with fluorochromes or indirectly with fluorescently conjugated antibodies, to detect these associations. Although useful, these techniques are consistently unable to include all host cells in the analysis while excluding free, aggregated bacteria. This study describes a new flow cytometry method of assessing bacterial adherence to host cells based on direct fluorescent labeling of both bacteria and host cells. Eukaryotic host cells were labeled with PKH-26, a red fluorescent dye, and bacteria were labeled with fluorescein isothiocyanate, a green fluorescent dye. The red host cells were gated and the mean green fluorescence intensity (MFI) of these red cells was determined. We used MFI values obtained from control samples (unlabeled and labeled host cells with unlabeled bacteria) to eliminate contributions due to autofluorescence. The final MFI values represent fluorescence of host cells resulting from the adherent bacteria. Because all red fluorescent cells are analyzed, this method includes all the eukaryotic cells for analysis but excludes all free or aggregated bacteria that are not bound to target cells.
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Affiliation(s)
| | - Thomas G. Pistole
- Corresponding author. Tel.: +1 603 862 0111; fax +1 603 862 2621, E-mail address:
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Sittka A, Pfeiffer V, Tedin K, Vogel J. The RNA chaperone Hfq is essential for the virulence of Salmonella typhimurium. Mol Microbiol 2006; 63:193-217. [PMID: 17163975 PMCID: PMC1810395 DOI: 10.1111/j.1365-2958.2006.05489.x] [Citation(s) in RCA: 297] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The RNA chaperone, Hfq, plays a diverse role in bacterial physiology beyond its original role as a host factor required for replication of Qβ RNA bacteriophage. In this study, we show that Hfq is involved in the expression and secretion of virulence factors in the facultative intracellular pathogen, Salmonella typhimurium. A Salmonella hfq deletion strain is highly attenuated in mice after both oral and intraperitoneal infection, and shows a severe defect in invasion of epithelial cells and a growth defect in both epithelial cells and macrophages in vitro. Surprisingly, we find that these phenotypes are largely independent of the previously reported requirement of Hfq for expression of the stationary phase sigma factor, RpoS. Our results implicate Hfq as a key regulator of multiple aspects of virulence including regulation of motility and outer membrane protein (OmpD) expression in addition to invasion and intracellular growth. These pleiotropic effects are suggested to involve a network of regulatory small non-coding RNAs, placing Hfq at the centre of post-transcriptional regulation of virulence gene expression in Salmonella. In addition, the hfq mutation appears to cause a chronic activation of the RpoE-mediated envelope stress response which is likely due to a misregulation of membrane protein expression.
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Affiliation(s)
- Alexandra Sittka
- Max Planck Institute for Infection BiologyRNA Biology Group, Berlin, Germany
| | - Verena Pfeiffer
- Max Planck Institute for Infection BiologyRNA Biology Group, Berlin, Germany
| | - Karsten Tedin
- Institut für Mikrobiologie und Tierseuchen, Freie Universität BerlinBerlin, Germany
| | - Jörg Vogel
- Max Planck Institute for Infection BiologyRNA Biology Group, Berlin, Germany
- *For correspondence. E-mail ; Tel. (+49) 30 28460 265; Fax (+49) 30 28460 244
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