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Garrido-Palazuelos LI, Aguirre-Sánchez JR, Castro-Del Campo N, López-Cuevas O, González-Torres B, Chaidez C, Medrano-Félix JA. Genomic characteristics of Salmonella Montevideo and Pomona: impact of isolation source on antibiotic resistance, virulence and metabolic capacity. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2024:1-16. [PMID: 38576268 DOI: 10.1080/09603123.2024.2336597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024]
Abstract
Salmonella enterica is known for its disease-causing serotypes, including Montevideo and Pomona. These serotypes have been found in various environments, including river water, sediments, food, and animals. However, the global spread of these serotypes has increased, leading to many reported infections and outbreaks. The goal of this study was the genomic analysis of 48 strains of S. Montevideo and S. Pomona isolated from different sources, including clinical. Results showed that environmental strains carried more antibiotic resistance genes than the clinical strains, such as genes for resistance to aminoglycosides, chloramphenicol, and sulfonamides. Additionally, the type 4 secretion system, was only found in environmental strains. .Also many phosphotransferase transport systems were identified and the presence of genes for the alternative pathway Entner-Doudoroff. The origin of isolation may have a significant impact on the ability of Salmonella isolates to adapt and survive in different environments, leading to genomic flexibility and a selection advantage.
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Affiliation(s)
- Lennin Isaac Garrido-Palazuelos
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - José Roberto Aguirre-Sánchez
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - Nohelia Castro-Del Campo
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - Osvaldo López-Cuevas
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - Berenice González-Torres
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - Cristóbal Chaidez
- Laboratorio Nacional Para la Investigación En Inocuidad Alimentaria (LANIIA), Centro de Investigación En Alimentación y Desarrollo A.C (CIAD), Culiacán, México
| | - José Andrés Medrano-Félix
- Investigadoras e investigadores por México Centro de Investigación En Alimentación y Desarrollo A.C. Laboratorio Nacional para la Investigación en Inocuidad Alimentaria, Culiacán, México
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2
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da Silva MR, Alves de Almeida F, Coelho AÍM, da Silva FL, Vanetti MCD. Enhancing cell resistance for production of mixed microbiological reference materials with Salmonella and coliforms by freeze-drying. Braz J Microbiol 2022; 53:2107-2119. [PMID: 35962856 PMCID: PMC9679061 DOI: 10.1007/s42770-022-00808-z] [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: 02/08/2022] [Accepted: 07/29/2022] [Indexed: 01/13/2023] Open
Abstract
The reference material (RM) is a technical requirement for the quality assurance of analytical results and proficiency tests or interlaboratory comparisons. Microbiological RMs are most available in the dehydrated form, mainly by freeze-drying, and maintaining bacterial survival after preparation is a challenge. Thus, obtaining the most resistant cells is essential. Considering that bacteria present cross-response to dehydration after being submitted to an array of stress conditions, this study aimed to evaluate the influence of growth conditions on enterobacteria for the production of mixed microbiological RMs by freeze-drying in skim milk powder. Salmonella enterica serovar Enteritidis, Cronobacter sakazakii, Escherichia coli, and Citrobacter freundii were grown in a minimal medium with 0.5 M NaCl and 0 to 5.0 mM of manganese sulfate (MnSO4) until stationary phase. Salmonella Enteritidis presented an increased resistance to dehydration in the presence of Mn, while C. sakazakii was the most resistant to freeze-drying and further storage for 90 days. Mixed microbiological RMs were produced by freeze-drying and containing Salmonella Enteritidis and coliforms in skim milk powder with 100 mM of trehalose and the Salmonella survival rate was 91.2 to 93.6%. The mixed RM was stable after 30 days at -20 °C, and Salmonella and coliforms were detected by different methods being, the Rambach Agar the best for the bacterial differentiation. The results showed that the culture conditions applied in this study resulted in bacterial cells being more resistant to dehydration, freeze-drying, and stabilization for the production of mixed microbiological RMs more stable and homogeneous.
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Affiliation(s)
- Maria Roméria da Silva
- Department of Microbiology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
- Department of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Felipe Alves de Almeida
- Department of Nutrition, Universidade Federal de Juiz de Fora, Governador Valadares, MG, 35032-620, Brazil
| | | | - Fernanda Lopes da Silva
- Department of Food Technology, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
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3
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Mandal RK, Jiang T, Kwon YM. Genetic Determinants in Salmonella enterica Serotype Typhimurium Required for Overcoming In Vitro Stressors in the Mimicking Host Environment. Microbiol Spectr 2021; 9:e0015521. [PMID: 34878334 PMCID: PMC8653844 DOI: 10.1128/spectrum.00155-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 10/29/2021] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serotype Typhimurium, a nontyphoidal Salmonella (NTS), results in a range of enteric diseases, representing a major disease burden worldwide. There is still a significant portion of Salmonella genes whose mechanistic basis to overcome host innate defense mechanisms largely remains unknown. Here, we have applied transposon insertion sequencing (Tn-seq) method to unveil the genetic factors required for the growth or survival of S. Typhimurium under various host stressors simulated in vitro. A highly saturating Tn5 library of S. Typhimurium 14028s was subjected to selection during growth in the presence of short-chain fatty acid (100 mM propionate), osmotic stress (3% NaCl), or oxidative stress (1 mM H2O2) or survival in extreme acidic pH (30 min in pH 3) or starvation (12 days in 1× phosphate-buffered saline [PBS]). We have identified a total of 339 conditionally essential genes (CEGs) required to overcome at least one of these conditions mimicking host insults. Interestingly, all eight genes encoding FoF1-ATP synthase subunit proteins were required for fitness in all five stresses. Intriguingly, a total of 88 genes in Salmonella pathogenicity islands (SPI), including SPI-1, SPI-2, SPI-3, SPI-5, SPI-6, and SPI-11, are also required for fitness under the in vitro conditions. Additionally, by comparative analysis of the genes identified in this study and the genes previously shown to be required for in vivo fitness, we identified novel genes (marBCT, envF, barA, hscA, rfaQ, rfbI, and the genes encoding putative proteins STM14_1138, STM14_3334, STM14_4825, and STM_5184) that have compelling potential for the development of vaccines and antibacterial drugs to curb Salmonella infection. IMPORTANCE Salmonella enterica serotype Typhimurium is a major human bacterial pathogen that enters the food chain through meat animals asymptomatically carrying this pathogen. Despite the rich genome sequence data, a significant portion of Salmonella genes remain to be characterized for their potential contributions to virulence. In this study, we used transposon insertion sequencing (Tn-seq) to elucidate the genetic factors required for growth or survival under various host stressors, including short-chain fatty acids, osmotic stress, oxidative stress, extreme acid, and starvation. Among the total of 339 conditionally essential genes (CEGs) that are required under at least one of these five stress conditions were 221 previously known virulence genes required for in vivo fitness during infection in at least one of four animal species, including mice, chickens, pigs, and cattle. This comprehensive map of virulence phenotype-genotype in S. Typhimurium provides a roadmap for further interrogation of the biological functions encoded by the genome of this important human pathogen to survive in hostile host environments.
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Affiliation(s)
- Rabindra K. Mandal
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Tieshan Jiang
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
| | - Young Min Kwon
- Center of Excellence for Poultry Science, University of Arkansas System Division of Agriculture, Fayetteville, Arkansas, USA
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, Arkansas, USA
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4
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Arunima A, Suar M. Glucose Starvation, Magnesium Ion Starvation, and Bile Stress Assays. Bio Protoc 2021; 11:e4157. [PMID: 34692907 DOI: 10.21769/bioprotoc.4157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/07/2021] [Accepted: 06/15/2021] [Indexed: 11/02/2022] Open
Abstract
Salmonella enterica serovar Enteritidis (S. Enteritidis) is a leading causative pathogen for food-borne gastroenteritis. During its course of infection, it confronts myriads of physiological barriers inside the host, such as nutrient deprivation, low micronutrient availability, and toxicity from bile salts, to promote bacterial survival and infection inside the host. The ability of the pathogen to overcome these stressful conditions determines the degree of virulence in the host. Therefore, assessment of the survival of a pathogen during different stress conditions, like glucose starvation, magnesium starvation, and bile stress, are important parameters to assess the virulence of the pathogen. Here, we describe protocols for estimating the survival of the pathogen during the above-mentioned stress conditions. We culture S. Enteritidis in an appropriate growth medium to a required O.D.600 and treat it with glucose starvation (M9 minimal culture medium containing 0.03% glucose), magnesium starvation (M9 minimal culture medium containing 20 µM MgSO4), and bile stress (bacterial cells treated with 15% bile salts in Luria Bertani (LB) culture medium) conditions. The number of surviving bacteria is obtained after the treatment by calculating the colony-forming units (CFU) of the surviving pathogen obtained on LB agar plates at relevant time intervals. The experiments are performed in biological replicates, and statistical analysis is performed to validate the experimental findings. The methodology of these stress response assays is simple and can be adapted to study the pathogenesis and stress response in other relevant and culturable enteric pathogens.
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Affiliation(s)
- Aryashree Arunima
- School of Biotechnology, Kalinga Institute of Industrial Technology-(KIIT) University, Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, Kalinga Institute of Industrial Technology-(KIIT) University, Bhubaneswar, India
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Impact of the Resistance Responses to Stress Conditions Encountered in Food and Food Processing Environments on the Virulence and Growth Fitness of Non-Typhoidal Salmonellae. Foods 2021; 10:foods10030617. [PMID: 33799446 PMCID: PMC8001757 DOI: 10.3390/foods10030617] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/24/2021] [Accepted: 03/10/2021] [Indexed: 01/22/2023] Open
Abstract
The success of Salmonella as a foodborne pathogen can probably be attributed to two major features: its remarkable genetic diversity and its extraordinary ability to adapt. Salmonella cells can survive in harsh environments, successfully compete for nutrients, and cause disease once inside the host. Furthermore, they are capable of rapidly reprogramming their metabolism, evolving in a short time from a stress-resistance mode to a growth or virulent mode, or even to express stress resistance and virulence factors at the same time if needed, thanks to a complex and fine-tuned regulatory network. It is nevertheless generally acknowledged that the development of stress resistance usually has a fitness cost for bacterial cells and that induction of stress resistance responses to certain agents can trigger changes in Salmonella virulence. In this review, we summarize and discuss current knowledge concerning the effects that the development of resistance responses to stress conditions encountered in food and food processing environments (including acid, osmotic and oxidative stress, starvation, modified atmospheres, detergents and disinfectants, chilling, heat, and non-thermal technologies) exerts on different aspects of the physiology of non-typhoidal Salmonellae, with special emphasis on virulence and growth fitness.
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6
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Aguirre-Sanchez JR, Ibarra-Rodriguez JR, Vega-Lopez IF, Martínez-Urtaza J, Chaidez-Quiroz C. Genomic signatures of adaptation to natural settings in non-typhoidal Salmonella enterica Serovars Saintpaul, Thompson and Weltevreden. INFECTION GENETICS AND EVOLUTION 2021; 90:104771. [PMID: 33592318 DOI: 10.1016/j.meegid.2021.104771] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 10/22/2022]
Abstract
Salmonella enterica is a pathogenic bacterium responsible for intestinal illness and systemic diseases such as typhoid and paratyphoid fevers. Among clinical manifestation classification, non-typhoidal Salmonella is mainly known as foodborne pathogen associated with the consumption of fecal contaminated food and water. Even though Salmonella hosts include humans and warm-blooded animals, it has been found in non-host environments as river water where the bacteria use different strategies to fitness the environment persisting and establishment. Now with the availability of WGS and bioinformatics tools, we can explore bacterial genomes with higher resolution to increase our understanding of specific genetic signatures among environmental and clinical isolates, being the goal of this work. Pangenome construction allowed the detection of specific environmental and clinical gene clusters related to metabolism and secretion systems as the main signature respectively. Specifically, D-galactonate degradation pathway was observed mainly in environmental genomes while T3SS and flagellum genes were detected for all clinical but not for all environmental isolates. Gene duplication and pseudogenes accumulation were detected as the main adaptation strategy for environmental isolates; thus, isolation source may play an important role in genome plasticity, conferring a selective advantage to survive and persist for environmental Salmonella isolates. Intact prophage sequences with cargo genes were observable for both isolation sources playing an important role in virulence contribution.
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Affiliation(s)
| | | | - I F Vega-Lopez
- Parque de Innovación Tecnológica de la Universidad Autónoma de Sinaloa, Culiacán, Mexico
| | - J Martínez-Urtaza
- Departement of Genetics and Microbiology, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - C Chaidez-Quiroz
- Centro de Investigación en Alimentación y Desarrollo, Culiacán, Mexico.
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7
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Harrand AS, Kovac J, Carroll LM, Guariglia-Oropeza V, Kent DJ, Wiedmann M. Assembly and Characterization of a Pathogen Strain Collection for Produce Safety Applications: Pre-growth Conditions Have a Larger Effect on Peroxyacetic Acid Tolerance Than Strain Diversity. Front Microbiol 2019; 10:1223. [PMID: 31231329 PMCID: PMC6558390 DOI: 10.3389/fmicb.2019.01223] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 05/16/2019] [Indexed: 12/21/2022] Open
Abstract
Effective control of foodborne pathogens on produce requires science-based validation of interventions and control strategies, which typically involves challenge studies with a set of bacterial strains representing the target pathogens or appropriate surrogates. In order to facilitate these types of studies, a produce-relevant strain collection was assembled to represent strains from produce outbreaks or pre-harvest environments, including Listeria monocytogenes (n = 11), Salmonella enterica (n = 23), shiga-toxin producing Escherichia coli (STEC) (n = 13), and possible surrogate organisms (n = 8); all strains were characterized by whole genome sequencing (WGS). Strain diversity was assured by including the 10 most common S. enterica serotypes, L. monocytogenes lineages I-IV, and E. coli O157 as well as selected "non-O157" STEC serotypes. As it has previously been shown that strains and genetic lineages of a pathogen may differ in their ability to survive different stress conditions, a subset of representative strains for each "pathogen group" (e.g., Salmonella, STEC) was selected and assessed for survival of exposure to peroxyacetic acid (PAA) using strains pre-grown under different conditions including (i) low pH, (ii) high salt, (iii) reduced water activity, (iv) different growth phases, (v) minimal medium, and (vi) different temperatures (21°C, 37°C). The results showed that across the three pathogen groups pre-growth conditions had a larger effect on bacterial reduction after PAA exposure as compared to strain diversity. Interestingly, bacteria exposed to salt stress (4.5% NaCl) consistently showed the least reduction after exposure to PAA; however, for STEC, strains pre-grown at 21°C were as tolerant to PAA exposure as strains pre-grown under salt stress. Overall, our data suggests that challenge studies conducted with multi-strain cocktails (pre-grown under a single specific condition) may not necessarily reflect the relevant phenotypic range needed to appropriately assess different intervention strategies.
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Affiliation(s)
| | - Jasna Kovac
- Department of Food Science, Pennsylvania State University, University Park, PA, United States
| | - Laura M. Carroll
- Department of Food Science, Cornell University, Ithaca, NY, United States
| | | | - David J. Kent
- Department of Statistical Science, Cornell University, Ithaca, NY, United States
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY, United States
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Dawoud TM, Davis ML, Park SH, Kim SA, Kwon YM, Jarvis N, O’Bryan CA, Shi Z, Crandall PG, Ricke SC. The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review. Front Vet Sci 2017; 4:93. [PMID: 28660201 PMCID: PMC5469892 DOI: 10.3389/fvets.2017.00093] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection.
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Affiliation(s)
- Turki M. Dawoud
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Morgan L. Davis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Si Hong Park
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Sun Ae Kim
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Young Min Kwon
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, United States
| | - Nathan Jarvis
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Corliss A. O’Bryan
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Zhaohao Shi
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Philip G. Crandall
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | - Steven C. Ricke
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR, United States
- Center for Food Safety, University of Arkansas, Fayetteville, AR, United States
- Department of Food Science, University of Arkansas, Fayetteville, AR, United States
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9
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Aluksanasuwan S, Sueksakit K, Fong-Ngern K, Thongboonkerd V. Role of HSP60 (HSPD1) in diabetes-induced renal tubular dysfunction: regulation of intracellular protein aggregation, ATP production, and oxidative stress. FASEB J 2017; 31:2157-2167. [PMID: 28196897 DOI: 10.1096/fj.201600910rr] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 01/23/2017] [Indexed: 12/28/2022]
Abstract
Because underlying mechanisms of diabetic nephropathy/tubulopathy remained poorly understood, we aimed to define a key protein involving in hyperglycemia-induced renal tubular dysfunction. All altered renal proteins identified from previous large-scale proteome studies were subjected to global protein network analysis, which revealed heat shock protein 60 (HSP60, also known as HSPD1) as the central node of protein-protein interactions. Functional validation was performed using small interfering RNA (siRNA) to knock down HSP60 (siHSP60). At 48 h after exposure to high glucose (HG) (25 mM), Madin-Darby canine kidney (MDCK) renal tubular cells transfected with controlled siRNA (siControl) had significantly increased level of HSP60 compared to normal glucose (NG) (5.5 mM), whereas siHSP60-transfected cells showed a dramatically decreased HSP60 level. siHSP60 modestly increased intracellular protein aggregates in both NG and HG conditions. Luciferin-luciferase assay showed that HG modestly increased intracellular ATP, and siHSP60 further enhanced such an increase. OxyBlot assay showed significantly increased level of oxidized proteins in HG-treated siControl-transfected cells, whereas siHSP60 caused marked increase of oxidized proteins under the NG condition. However, the siHSP60-induced accumulation of oxidized proteins was abolished by HG. In summary, our data demonstrated that HSP60 plays roles in regulation of intracellular protein aggregation, ATP production, and oxidative stress in renal tubular cells. Its involvement in HG-induced tubular cell dysfunction was most likely via regulation of intracellular ATP production.-Aluksanasuwan, S., Sueksakit, K., Fong-ngern, K., Thongboonkerd, V. Role of HSP60 (HSPD1) in diabetes-induced renal tubular dysfunction: regulation of intracellular protein aggregation, ATP production, and oxidative stress.
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Affiliation(s)
- Siripat Aluksanasuwan
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand
| | - Kanyarat Sueksakit
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand
| | - Kedsarin Fong-Ngern
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; .,Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand
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10
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Won G, Lee JH. Effectiveness of F18 + Fimbrial Antigens Released by a Novel Autolyzed Salmonella Expression System as a Vaccine Candidate against Lethal F18 + STEC Infection. Front Microbiol 2016; 7:1835. [PMID: 27920758 PMCID: PMC5118419 DOI: 10.3389/fmicb.2016.01835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/01/2016] [Indexed: 12/04/2022] Open
Abstract
Porcine edema disease (ED) caused by Shiga toxin 2e producing Escherichia coli expressing F18ab+ fimbriae (F18ab+STEC) frequently occurs in post-weaned piglets, resulting in a significant economic loss in swine industries worldwide. In the present study, we proposed an efficient prevention scheme against ED in which the attenuated Salmonella Typhimurium inactivated by the E-mediated cell lysis to deliver target antigens, FedF and FedA, which function in fimbrial-mediated adhesion and as a major subunit of F18ab+fimbriae, respectively. The co-expression of FedA and FedF protein with outer membrane protein A signal peptide was confirmed in the resultant strains JOL1460 and JOL1464 by immunoblot analysis. Immunization with the candidate strains in mice led to the significant generation of immunoglobulin (Ig) G, specific to both antigens and secretory IgA specific to FedF (P < 0.05). The titers of IgG isotypes, IgG1 and IgG2a, used as markers for T-helpers (Th)-2 and Th-1lymphocytes, respectively, also significantly increased in the immunized group (P < 0.05). The increase in CD3+CD4+ T lymphocyte subpopulation and in vitro proliferative activity was observed in in vivo stimulated splenocytes, which indicated the immunostimulatory effect of the candidate strains. Moreover, the immunized mice were completely protected from a lethal challenge against wild-type F18+STEC whereas 28% of mice died in the non-immunized group. This study demonstrated that the inactivated Salmonella system could efficiently release FedF and FedA and induce robust immune responses specific to the target antigens, which is sufficient to protect the mice from the lethal challenge.
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Affiliation(s)
- Gayeon Won
- College of Veterinary Medicine, Chonbuk National University Iksan, South Korea
| | - John H Lee
- College of Veterinary Medicine, Chonbuk National University Iksan, South Korea
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11
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Runkel S, Wells HC, Rowley G. Living with Stress: A Lesson from the Enteric Pathogen Salmonella enterica. ADVANCES IN APPLIED MICROBIOLOGY 2016; 83:87-144. [PMID: 23651595 DOI: 10.1016/b978-0-12-407678-5.00003-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ability to sense and respond to the environment is essential for the survival of all living organisms. Bacterial pathogens such as Salmonella enterica are of particular interest due to their ability to sense and adapt to the diverse range of conditions they encounter, both in vivo and in environmental reservoirs. During this cycling from host to non-host environments, Salmonella encounter a variety of environmental insults ranging from temperature fluctuations, nutrient availability and changes in osmolarity, to the presence of antimicrobial peptides and reactive oxygen/nitrogen species. Such fluctuating conditions impact on various areas of bacterial physiology including virulence, growth and antimicrobial resistance. A key component of the success of any bacterial pathogen is the ability to recognize and mount a suitable response to the discrete chemical and physical stresses elicited by the host. Such responses occur through a coordinated and complex programme of gene expression and protein activity, involving a range of transcriptional regulators, sigma factors and two component regulatory systems. This review briefly outlines the various stresses encountered throughout the Salmonella life cycle and the repertoire of regulatory responses with which Salmonella counters. In particular, how these Gram-negative bacteria are able to alleviate disruption in periplasmic envelope homeostasis through a group of stress responses, known collectively as the Envelope Stress Responses, alongside the mechanisms used to overcome nitrosative stress, will be examined in more detail.
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Affiliation(s)
- Sebastian Runkel
- School of Biological Sciences, University of East Anglia, Norwich, UK
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12
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Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens. Microorganisms 2015; 3:746-58. [PMID: 27682115 PMCID: PMC5023268 DOI: 10.3390/microorganisms3040746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/28/2015] [Accepted: 10/21/2015] [Indexed: 11/30/2022] Open
Abstract
The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation) is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance). To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C), low pH (pH 2.8), and oxidative stress (15 mM H2O2). In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth.
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Li J, Overall CC, Nakayasu ES, Kidwai AS, Jones MB, Johnson RC, Nguyen NT, McDermott JE, Ansong C, Heffron F, Cambronne ED, Adkins JN. Analysis of the Salmonella regulatory network suggests involvement of SsrB and H-NS in σ(E)-regulated SPI-2 gene expression. Front Microbiol 2015; 6:27. [PMID: 25713562 PMCID: PMC4322710 DOI: 10.3389/fmicb.2015.00027] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/08/2015] [Indexed: 02/04/2023] Open
Abstract
The extracytoplasmic functioning sigma factor σE is known to play an essential role for Salmonella enterica serovar Typhimurium to survive and proliferate in macrophages and mice. However, its regulatory network is not well-characterized, especially during infection. Here we used microarray to identify genes regulated by σE in Salmonella grown in three conditions: a nutrient-rich condition and two others that mimic early and late intracellular infection. We found that in each condition σE regulated different sets of genes, and notably, several global regulators. When comparing nutrient-rich and infection-like conditions, large changes were observed in the expression of genes involved in Salmonella pathogenesis island (SPI)-1 type-three secretion system (TTSS), SPI-2 TTSS, protein synthesis, and stress responses. In total, the expression of 58% of Salmonella genes was affected by σE in at least one of the three conditions. An important finding is that σE up-regulates SPI-2 genes, which are essential for Salmonella intracellular survival, by up-regulating SPI-2 activator ssrB expression at the early stage of infection and down-regulating SPI-2 repressor hns expression at a later stage. Moreover, σE is capable of countering the silencing of H-NS, releasing the expression of SPI-2 genes. This connection between σE and SPI-2 genes, combined with the global regulatory effect of σE, may account for the lethality of rpoE-deficient Salmonella in murine infection.
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Affiliation(s)
- Jie Li
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Christopher C Overall
- Biological Sciences Division, Pacific Northwest National Laboratory Richland, WA, USA
| | - Ernesto S Nakayasu
- Biological Sciences Division, Pacific Northwest National Laboratory Richland, WA, USA
| | - Afshan S Kidwai
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Marcus B Jones
- Department of Infectious Diseases, J. Craig Venter Institute Rockville, MD, USA
| | - Rudd C Johnson
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Nhu T Nguyen
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Jason E McDermott
- Biological Sciences Division, Pacific Northwest National Laboratory Richland, WA, USA
| | - Charles Ansong
- Biological Sciences Division, Pacific Northwest National Laboratory Richland, WA, USA
| | - Fred Heffron
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Eric D Cambronne
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University Portland, OR, USA
| | - Joshua N Adkins
- Biological Sciences Division, Pacific Northwest National Laboratory Richland, WA, USA
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Fida TT, Moreno-Forero SK, Heipieper HJ, Springael D. Physiology and transcriptome of the polycyclic aromatic hydrocarbon-degrading Sphingomonas sp. LH128 after long-term starvation. Microbiology (Reading) 2013; 159:1807-1817. [DOI: 10.1099/mic.0.065870-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Tekle Tafese Fida
- Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Silvia K. Moreno-Forero
- Department of Fundamental Microbiology, University of Lausanne, Bâtiment Biophore Quartier Sorge, 1015 Lausanne, Switzerland
| | - Hermann J. Heipieper
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research–UFZ, Permoserstr. 15, 04318 Leipzig, Germany
| | - Dirk Springael
- Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
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Novel inducers of the envelope stress response BaeSR in Salmonella Typhimurium: BaeR is critically required for tungstate waste disposal. PLoS One 2011; 6:e23713. [PMID: 21886814 PMCID: PMC3160322 DOI: 10.1371/journal.pone.0023713] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 07/22/2011] [Indexed: 11/21/2022] Open
Abstract
The RpoE and CpxR regulated envelope stress responses are extremely important for SalmonellaTyphimurium to cause infection in a range of hosts. Until now the role for BaeSR in both the Salmonella Typhimurium response to stress and its contribution to infection have not been fully elucidated. Here we demonstrate stationary phase growth, iron and sodium tungstate as novel inducers of the BaeRregulon, with BaeR critically required for Salmonella resistance to sodium tungstate. We show that functional overlap between the resistance nodulation-cell division (RND) multidrug transporters, MdtA, AcrD and AcrB exists for the waste disposal of tungstate from the cell. We also point to a role for enterobactinsiderophores in the protection of enteric organisms from tungstate, akin to the scenario in nitrogen fixing bacteria. Surprisingly, BaeR is the first envelope stress response pathway investigated in S. Typhimurium that is not required for murine typhoid in either ityS or ityR mouse backgrounds. BaeR is therefore either required for survival in larger mammals such as pigs or calves, an avian host such as chickens, or survival out with the host altogether where Salmonella and related enterics must survive in soil and water.
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Calhoun LN, Liyanage R, Lay JO, Kwon YM. Proteomic analysis of Salmonella enterica serovar Enteritidis following propionate adaptation. BMC Microbiol 2010; 10:249. [PMID: 20920181 PMCID: PMC2957393 DOI: 10.1186/1471-2180-10-249] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 09/28/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella Enteritidis is a highly prevalent and persistent foodborne pathogen and is therefore a leading cause of nontyphoidal gastrointestinal disease worldwide. A variety of stresses are endured throughout its infection cycle, including high concentrations of propionate (PA) within food processing systems and within the gut of infected hosts. Prolonged PA exposure experienced in such milieus may have a drastic effect on the proteome of Salmonella Enteritidis subjected to this stress. RESULTS In this study, we used 2 D gel electrophoresis to examine the proteomes of PA adapted and unadapted S. Enteritidis and have identified five proteins that are upregulated in PA adapted cultures using standard peptide mass fingerprinting by MALDI-TOF-MS and sequencing by MALDI LIFT-TOF/TOF tandem mass spectrometry. Of these five, two significant stress-related proteins (Dps and CpxR) were shown (via qRT-PCR analysis) to be upregulated at the transcriptional level as well. Unlike the wild type when adapted to PA (which demonstrates significant acid resistance), PA adapted S. Enteritidis ∆dps and S. Enteritidis ∆cpxR were at a clear disadvantage when challenged to a highly acidic environment. However, we found the acid resistance to be fully restorable after genetic complementation. CONCLUSIONS This work reveals a significant difference in the proteomes of PA adapted and unadapted S. Enteritidis and affirms the contribution of Dps and CpxR in PA induced acid resistance.
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Affiliation(s)
- Leona N Calhoun
- Cell and Molecular Biology Program, Department of Poultry Science, University of Arkansas, 1260 W, Maple Avenue, Fayetteville, AR 72701, USA
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Periplasmic peptidyl-prolyl isomerases SurA and FkpA play an important role in the starvation-stress response (SSR) of Salmonella enterica serovar Typhimurium. Antonie van Leeuwenhoek 2010; 98:51-63. [PMID: 20232248 DOI: 10.1007/s10482-010-9428-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 03/04/2010] [Indexed: 10/19/2022]
Abstract
Carbon-energy source (C)-starved cells of Salmonella enterica serovar Typhimurium (S. Typhimurium) are remarkably more resistant to stress than actively growing ones. Carbon-starved S. Typhimurium is capable of withstanding extended periods of starvation and assault from a number of different stresses that rapidly kill growing cells. These unique properties of the C-starved cell are the direct result of a series of genetic and physiological adaptations referred to as the starvation-stress response (SSR). Previous work established that the SSR of S. Typhimurium is partially regulated by the extracytoplasmic function sigma factor sigma(E). As part of an effort to identify sigma(E)-regulated SSR genes, we investigated surA and fkpA, encoding two different classes of peptidyl-prolyl isomerase that function in folding cell envelope proteins. Both surA and fkpA are members of the heat-shock-inducible sigma(E) regulon of Escherichia coli. Although both genes are expressed in C-starved Salmonella cells, evidence indicates that surA and fkpA are not C-starvation-inducible. Furthermore, their expression during C-starvation does not appear to be sigma(E)-dependent. Nonetheless, surA and fkpA proved to be important, to differing degrees, for long-term C-starvation survival and for the cross-resistance of C-starved cells to high temperature, acidic pH, and the antimicrobial peptide polymyxin B, but neither were required for cross-resistance to oxidative stress. These results point to fundamental differences between heat-shock-inducible and C-starvation-inducible genes regulated by sigma(E) and suggest that genes other than surA and fkpA are involved in the sigma(E)-regulated branch of the SSR in Salmonella.
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Lewis C, Skovierova H, Rowley G, Rezuchova B, Homerova D, Stevenson A, Spencer J, Farn J, Kormanec J, Roberts M. Salmonella enterica Serovar Typhimurium HtrA: regulation of expression and role of the chaperone and protease activities during infection. MICROBIOLOGY-SGM 2009; 155:873-881. [PMID: 19246758 DOI: 10.1099/mic.0.023754-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
HtrA is a bifunctional stress protein required by many bacterial pathogens to successfully cause infection. Salmonella enterica serovar Typhimurium (S. Typhimurium) htrA mutants are defective in intramacrophage survival and are highly attenuated in mice. Transcription of htrA in Escherichia coli is governed by a single promoter that is dependent on sigma(E) (RpoE). S. Typhimurium htrA also possesses a sigma(E)-dependent promoter; however, we found that the absence of sigma(E) had little effect on production of HtrA by S. Typhimurium. This suggests that additional promoters control expression of htrA in S. Typhimurium. We identified three S. Typhimurium htrA promoters. Only the most proximal promoter, htrAp3, was sigma(E) dependent. The other promoters, htrAp1 and htrAp2, are probably recognized by the principal sigma factor sigma(70). These two promoters were constitutively expressed but were also slightly induced by heat shock. Thus expression of htrA is different in S. Typhimurium and E. coli. The role of HtrA is to deal with misfolded/damaged proteins in the periplasm. It can do this either by degrading (protease activity) or folding/capturing (chaperone/sequestering, C/S, activity) the aberrant protein. We investigated which of these functions are important to S. Typhimurium in vitro and in vivo. Point or deletion mutants of htrA that encode variant HtrA molecules have been used in previous studies to investigate the role of different regions of HtrA in C/S and protease activity. These htrA variants were placed under the control of the S. Typhimurium htrAP123 promoters and expressed in a S. Typhimurium htrA mutant, GVB1343. Both wild-type HtrA and HtrA (HtrA S210A) lacking protease activity enabled GVB1343 to grow at high temperature (46 degrees C). Both molecules also significantly enhanced the growth/survival of GVB1343 in the liver and spleen of mice during infection. However, expression of wild-type HtrA enabled GVB1343 to grow to much higher levels than expression of HtrA S210A. Thus both the protease and C/S functions of HtrA operate in vivo during infection but the protease function is probably more important. Absence of either PDZ domain completely abolished the ability of HtrA to complement the growth defects of GVB1343 in vitro or in vivo.
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Affiliation(s)
- Claire Lewis
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Henrieta Skovierova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Gary Rowley
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Bronislava Rezuchova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Dagmar Homerova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Andrew Stevenson
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Janice Spencer
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Jacinta Farn
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Jan Kormanec
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Mark Roberts
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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20
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Zheng W, Zhang M, Zhao Y, Wang Y, Miao K, Wei Z. Accumulation of antioxidant phenolic constituents in submerged cultures of Inonotus obliquus. BIORESOURCE TECHNOLOGY 2009; 100:1327-1335. [PMID: 18824349 DOI: 10.1016/j.biortech.2008.05.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 05/01/2008] [Accepted: 05/01/2008] [Indexed: 05/26/2023]
Abstract
Phenolic compounds produced by sclerotia of Inonotus obliquus are the active constituents responsible for antioxidant activities. In this study, I. obliquus was grown in a continuously stirred tank reactor (CSTR) to explore how it accumulates phenolic compounds in different culture media and whether these compounds possess antioxidant activities. Phenolic compounds produced by I. obliquus in the control medium consisted of melanins, flavonoids, polyphenols and small phenolics. Their accumulation was affected by adding H(2)O(2) to the medium, where increased levels of total intracellular phenols (TIP) and melanins, but less total extracellular phenol (TEP) occurred. Simultaneous exposure to H(2)O(2) and arbutin resulted in a further increase in TIP production and reduced accumulation of TEP. Both TIP and TEP obtained at different culture ages and media were active in scavenging superoxide anion and DPPH radicals. Therefore, production of phenolic compounds by I. obliquus is enhanced by imposing oxidative stress, which might allow it to be exploited as a reliable source of pharmaceutically important phenolic compounds.
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Affiliation(s)
- Weifa Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, Xuzhou Normal University, Xuzhou, China.
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21
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MacRitchie DM, Buelow DR, Price NL, Raivio TL. Two-component signaling and gram negative envelope stress response systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 631:80-110. [PMID: 18792683 DOI: 10.1007/978-0-387-78885-2_6] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Dawn M MacRitchie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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22
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MexCD-OprJ multidrug efflux system of Pseudomonas aeruginosa: involvement in chlorhexidine resistance and induction by membrane-damaging agents dependent upon the AlgU stress response sigma factor. Antimicrob Agents Chemother 2008; 52:4478-82. [PMID: 18838593 DOI: 10.1128/aac.01072-08] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The biocide chlorhexidine (CHX) as well as additional membrane-active agents were shown to induce expression of the mexCD-oprJ multidrug efflux operon, dependent upon the AlgU stress response sigma factor. Hyperexpression of this efflux system in nfxB mutants was also substantially AlgU dependent. CHX resistance correlated with efflux gene expression in various mutants, consistent with MexCD-OprJ being a determinant of CHX resistance.
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23
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Lewis C, Skovierova H, Rowley G, Rezuchova B, Homerova D, Stevenson A, Sherry A, Kormanec J, Roberts M. Small outer-membrane lipoprotein, SmpA, is regulated by σ E and has a role in cell envelope integrity and virulence of Salmonella enterica serovar Typhimurium. Microbiology (Reading) 2008; 154:979-988. [DOI: 10.1099/mic.0.2007/011999-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Claire Lewis
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Henrieta Skovierova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Gary Rowley
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Bronislava Rezuchova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Dagmar Homerova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Andrew Stevenson
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Aileen Sherry
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Jan Kormanec
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Mark Roberts
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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24
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Kenyon WJ, Nicholson KL, Rezuchova B, Homerova D, Garcia-Del Portillo F, Finlay BB, Pallen MJ, Kormanec J, Spector MP. Sigma(s)-Dependent carbon-starvation induction of pbpG (PBP 7) is required for the starvation-stress response in Salmonella enterica serovar Typhimurium. MICROBIOLOGY-SGM 2007; 153:2148-2158. [PMID: 17600059 DOI: 10.1099/mic.0.2007/005199-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Carbon-energy source starvation is a commonly encountered stress that can influence the epidemiology and virulence of Salmonella enterica serovars. Salmonella responds to C-starvation by eliciting the starvation-stress response (SSR), which allows for long-term C-starvation survival and cross-resistance to other stresses. The stiC locus was identified as a C-starvation-inducible, sigma(S)-dependent locus required for a maximal SSR. We report here that the stiC locus is an operon composed of the yohC (putative transport protein) and pbpG (penicillin-binding protein-7/8) genes. yohC pbpG transcription is initiated from a sigma(S)-dependent C-starvation-inducible promoter upstream of yohC. Another (sigma(S)-independent) promoter, upstream of pbpG, drives lower constitutive pbpG transcription, primarily during exponential phase. C-starvation-inducible pbpG expression was required for development of the SSR in 5 h, but not 24 h, C-starved cells; yohC was dispensable for the SSR. Furthermore, the yohC pbpG operon is induced within MDCK epithelial cells, but was not essential for oral virulence in BALB/c mice. Thus, PBP 7 is required for physiological changes, occurring within the first few hours of C-starvation, essential for the development of the SSR. Lack of PBP 7, however, can be compensated for by further physiological changes developed in 24 h C-starved cells. This supports the dynamic overlapping and distinct nature of resistance pathways within the Salmonella SSR.
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Affiliation(s)
- William J Kenyon
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
| | - Kristy L Nicholson
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
| | - Bronislava Rezuchova
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic
| | - Dagmar Homerova
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic
| | - Francisco Garcia-Del Portillo
- The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall, Vancouver, BC, Canada V6T 1Z4
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-CSIC, C/ Darwin 3, 28049 Madrid, Spain
| | - B Brett Finlay
- The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall, Vancouver, BC, Canada V6T 1Z4
| | - Mark J Pallen
- Division of Immunity and Infection, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Jan Kormanec
- Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic
| | - Michael P Spector
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
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Zheng J, He C, Singh VK, Martin NL, Jia Z. Crystal structure of a novel prokaryotic Ser/Thr kinase and its implication in the Cpx stress response pathway. Mol Microbiol 2007; 63:1360-71. [PMID: 17302814 DOI: 10.1111/j.1365-2958.2007.05611.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Cpx signalling system of Escherichia coli and Salmonella enterica senses extracytoplasmic stress and controls expression of factors that allow the bacterium to adapt to these stressors and thereby enhance survival. Many of the Cpx-responsive genes products are of unknown function. We determined the crystal structure of one of these gene products, called YihE in E. coli, which exhibits a eukaryotic kinase fold. Functional assays established that both YihE and the S. enterica YihE homologue, RdoA, undergo autophosphorylation and phosphorylate protein substrates at Ser/Thr residues in vitro, demonstrating that YihE/RdoA is a novel Ser/Thr protein kinase in prokaryotic cells. Phenotypic analysis of yihE/rdoA null strains indicates that this kinase is most abundant in stationary phase, and is important for long-term cell survival and for expression of surface appendages in both a Cpx-independent and -dependent manner. YihE/RdoA is therefore a previously unknown kinase component of a new type of bacterial phosphorelay mechanism, adding kinase activity as another response to the Cpx sensing system that functions to maintain cellular homeostasis.
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Affiliation(s)
- Jimin Zheng
- Department of Biochemistry, Queen's University, Kingston, Ontario, K7L 3N6, Canada
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26
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Kundinger MM, Zabala-Díaz IB, Chalova VI, Kim WK, Moore RW, Ricke SC. Characterization of rsmC as a potential reference gene for Salmonella Typhimurium gene expression during growth in spent media. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11694-007-9011-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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27
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Sauviac L, Philippe H, Phok K, Bruand C. An extracytoplasmic function sigma factor acts as a general stress response regulator in Sinorhizobium meliloti. J Bacteriol 2007; 189:4204-16. [PMID: 17400745 PMCID: PMC1913381 DOI: 10.1128/jb.00175-07] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sinorhizobium meliloti genes transcriptionally up-regulated after heat stress, as well as upon entry into stationary phase, were identified by microarray analyses. Sixty stress response genes were thus found to be up-regulated under both conditions. One of them, rpoE2 (smc01506), encodes a putative extracytoplasmic function (ECF) sigma factor. We showed that this sigma factor controls its own transcription and is activated by various stress conditions, including heat and salt, as well as entry into stationary phase after either carbon or nitrogen starvation. We also present evidence that the product of the gene cotranscribed with rpoE2 negatively regulates RpoE2 activity, and we therefore propose that it plays the function of anti-sigma factor. By combining transcriptomic, bioinformatic, and quantitative reverse transcription-PCR analyses, we identified 44 RpoE2-controlled genes and predicted the number of RpoE2 targets to be higher. Strikingly, more than one-third of the 60 stress response genes identified in this study are RpoE2 targets. Interestingly, two genes encoding proteins with known functions in stress responses, namely, katC and rpoH2, as well as a second ECF-encoding gene, rpoE5, were found to be RpoE2 regulated. Altogether, these data suggest that RpoE2 is a major global regulator of the general stress response in S. meliloti. Despite these observations, and although this sigma factor is well conserved among alphaproteobacteria, no in vitro nor in planta phenotypic difference from the wild-type strain could be detected for rpoE2 mutants. This therefore suggests that other important actors in the general stress response have still to be identified in S. meliloti.
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Affiliation(s)
- Laurent Sauviac
- Laboratoire des Interactions Plantes-Microorganismes, UMR 2594-441 CNRS-INRA, BP52627, 31326 Castanet-Tolosan Cedex, France
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Thongboonkerd V, Vanaporn M, Songtawee N, Kanlaya R, Sinchaikul S, Chen ST, Easton A, Chu K, Bancroft GJ, Korbsrisate S. Altered Proteome in Burkholderia pseudomallei rpoE Operon Knockout Mutant: Insights into Mechanisms of rpoE Operon in Stress Tolerance, Survival, and Virulence. J Proteome Res 2007; 6:1334-41. [PMID: 17346071 DOI: 10.1021/pr060457t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously shown that the alternative sigma factor sigmaE (RpoE), encoded by rpoE, is involved in stress tolerance and survival of Burkholderia pseudomallei. However, its molecular and pathogenic mechanisms remain unclear. In the present study, we applied gel-based, differential proteomics to compare the cellular proteome of an rpoE operon knockout mutant (RpoE Mut) to that of wild-type (K96243 WT) B. pseudomallei. Quantitative intensity analysis (n = 5 gels from 5 individual culture flasks in each group) revealed significantly differential expression of 52 proteins, which were subsequently identified by Q-TOF MS/MS. These included oxidative, osmotic, and other stress response proteins; chaperones; transcriptional/translational regulators; metabolic enzymes; proteins involved in cell wall synthesis, fatty synthesis, glycogen synthesis, and storage; exported proteins; secreted proteins; adhesion molecule; protease/peptidase; protease inhibitor; signaling proteins; and other miscellaneous proteins. The down-regulation of several stress response proteins, chaperones, transcriptional/translational regulators, and proteins involved in cell wall synthesis in RpoE Mut provided some new insights into the mechanisms of the rpoE operon for the stress tolerance and survival of B. pseudomallei. In addition, the proteomic data and in vivo study indicated that the rpoE operon is also involved in the virulence of B. pseudomallei. Our findings underscore the usefulness of proteomics for unraveling pathogenic mechanisms of diseases at the molecular level.
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Affiliation(s)
- Visith Thongboonkerd
- Medical Molecular Biology Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
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29
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Genome-Wide Scan of the Gene Expression Kinetics of Salmonella enterica Serovar Typhi during Hyperosmotic Stress. Int J Mol Sci 2007. [DOI: 10.3390/i8020116] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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30
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McMeechan A, Roberts M, Cogan TA, Jørgensen F, Stevenson A, Lewis C, Rowley G, Humphrey TJ. Role of the alternative sigma factors σ E and σ S in survival of Salmonella enterica serovar Typhimurium during starvation, refrigeration and osmotic shock. Microbiology (Reading) 2007; 153:263-9. [PMID: 17185555 DOI: 10.1099/mic.0.29235-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of Salmonella enterica serovar Typhimurium to survive environmental stress requires specific, coordinated, responses, which induce resistance to the stress condition. This study investigated the relative contribution of sigmaE and sigmaS, the sigma factors regulating extracytoplasmic and general stress response functions, respectively, to survival at low temperature and also in media of differing osmotic strength, conditions relevant to food preservation. To determine if low-temperature storage is a signal for sigmaE- and sigmaS-mediated survival, the ability of S. Typhimurium rpoE, rpoS and rpoE/rpoS mutants to survive in a saline starvation-survival model at a refrigeration temperature (4.5 degrees C) was examined. Under these conditions, the rpoE mutant was significantly (P<0.05) compromised compared to the parent and to an rpoS mutant. The double mutant in rpoE and rpoS displayed a cumulative defect in survival. In hyperosmotic environments (low aw) containing 6 % NaCl and at refrigeration temperature, both sigma factors were important for maximum survival but sigmaS played the dominant role. Analysis of the metabolic activity of starved populations at 4.5 and 37 degrees C revealed significantly (P<0.001) elevated electron-transport system activity in mutants in rpoE and rpoS, indicating a role for sigmaE- and sigmaS-regulated genes in maintaining energy homeostasis. Together these data demonstrate that sigmaE and sigmaS are important for survival of S. Typhimurium in conditions encountered during food processing and that the relative contribution of sigmaE and sigmaS is critically dependent on the precise nature of the stress.
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Affiliation(s)
- Alisdair McMeechan
- Division of Veterinary Pathology, Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Langford, Bristol BS40 5DU, UK
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31
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Rowley G, Spector M, Kormanec J, Roberts M. Pushing the envelope: extracytoplasmic stress responses in bacterial pathogens. Nat Rev Microbiol 2006; 4:383-94. [PMID: 16715050 DOI: 10.1038/nrmicro1394] [Citation(s) in RCA: 250] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite being nutrient rich, the tissues and fluids of vertebrates are hostile to microorganisms, and most bacteria that attempt to take advantage of this environment are rapidly eliminated by host defences. Pathogens have evolved various means to promote their survival in host tissues, including stress responses that enable bacteria to sense and adapt to adverse conditions. Many different stress responses have been described, some of which are responsive to one or a small number of cues, whereas others are activated by a broad range of insults. The surface layers of pathogenic bacteria directly interface with the host and can bear the brunt of the attack by the host armoury. Several stress systems that respond to perturbations in the microbial cell outside of the cytoplasm have been described and are known collectively as extracytoplasmic or envelope stress responses (ESRs). Here, we review the role of the ESRs in the pathogenesis of Gram-negative bacterial pathogens.
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Affiliation(s)
- Gary Rowley
- Molecular Bacteriology Group, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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32
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Rishi P, Kaur H, Tirkey N, Chopra K, Bharrhan S, Chanana V, Koul A. Are the increases in local tumour necrosis factor and lipid peroxidation observed in pre-starved mice infected with Salmonella typhimurium markers of increased liver damage? Microbes Infect 2006; 8:1695-701. [PMID: 16807038 DOI: 10.1016/j.micinf.2006.01.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 01/20/2006] [Accepted: 01/30/2006] [Indexed: 10/24/2022]
Abstract
Pathogenic microorganisms are known to sense and process signals within their hosts, including those resulting from starvation. Therefore, an attempt was made to evaluate the extent and the possible underlying mechanism of Salmonella typhimurium-induced hepatic damage using pre-starved laboratory mice. The following parameters were analysed, comparing control, fed infected, starved, and starved infected mice: the bacterial load in the liver, fluctuations in liver-derived enzymes alanine-aminotransferase and aspartate-aminotransferase, histopathological changes, lipid peroxidation as well as estimation of reduced glutathione, superoxide dismutase and catalase, along with the TNF content in livers. The number of bacterial cells recovered from starved infected livers at 3 days post-S. typhimurium inoculation was comparable to the number recovered from fed infected livers at 5 days post-Salmonella inoculation, indicating an early increase in the development of the bacteria in starved mice. A marked elevation in liver-derived enzymes in mouse serum and significant histopathological changes are markers of liver damage of higher amplitude in starved infected mice. Analysis of the liver indicated a significant increase in lipid peroxidation in starved infected mice compared to their control counterparts, a process coupled with increased TNF level. Although the reduced glutathione levels showed a marked increase in the starved infected mice, there was a significant decrease in superoxide dismutase and catalase activities in this group.
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Affiliation(s)
- Praveen Rishi
- Department of Microbiology, Basic Medical Sciences Block, Panjab University, Chandigarh, India.
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Skovierova H, Rowley G, Rezuchova B, Homerova D, Lewis C, Roberts M, Kormanec J. Identification of the σ
E regulon of Salmonella enterica serovar Typhimurium. Microbiology (Reading) 2006; 152:1347-1359. [PMID: 16622052 DOI: 10.1099/mic.0.28744-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The extracytoplasmic function sigma factor, σ
E, has been shown to play a critical role in virulence of Salmonella enterica serovar Typhimurium (S. Typhimurium). The previously optimized two-plasmid system has been used to identify S. Typhimurium promoters recognized by RNA polymerase containing σ
E. This method allowed identification of 34 σ
E-dependent promoters that direct expression of 62 genes in S. Typhimurium, 23 of which (including several specific for S. Typhimurium) have not been identified previously to be dependent upon σ
E in Escherichia coli. The promoters were confirmed in S. Typhimurium and transcriptional start points of the promoters were determined by S1-nuclease mapping. All the promoters contained sequences highly similar to the consensus sequence of σ
E-dependent promoters. The identified genes belonging to the S. Typhimurium σ
E-regulon encode proteins involved in primary metabolism, DNA repair systems and outer-membrane biogenesis, and regulatory proteins, periplasmic proteases and folding factors, proposed lipoproteins, and inner- and outer-membrane proteins with unknown functions. Several of these σ
E-dependent genes have been shown to play a role in virulence of S. Typhimurium.
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Affiliation(s)
- Henrieta Skovierova
- Institute of Molecular Biology, Centre of Excellence for Molecular Medicine, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
| | - Gary Rowley
- Molecular Bacteriology Group, Institute of Comparative Medicine, Department of Veterinary Pathology, Glasgow University Veterinary School, Bearsden Road, Glasgow G61 1QH, UK
| | - Bronislava Rezuchova
- Institute of Molecular Biology, Centre of Excellence for Molecular Medicine, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
| | - Dagmar Homerova
- Institute of Molecular Biology, Centre of Excellence for Molecular Medicine, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
| | - Claire Lewis
- Molecular Bacteriology Group, Institute of Comparative Medicine, Department of Veterinary Pathology, Glasgow University Veterinary School, Bearsden Road, Glasgow G61 1QH, UK
| | - Mark Roberts
- Molecular Bacteriology Group, Institute of Comparative Medicine, Department of Veterinary Pathology, Glasgow University Veterinary School, Bearsden Road, Glasgow G61 1QH, UK
| | - Jan Kormanec
- Institute of Molecular Biology, Centre of Excellence for Molecular Medicine, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
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Kenyon WJ, Thomas SM, Johnson E, Pallen MJ, Spector MP. Shifts from glucose to certain secondary carbon-sources result in activation of the extracytoplasmic function sigma factor sigmaE in Salmonella enterica serovar Typhimurium. MICROBIOLOGY-SGM 2005; 151:2373-2383. [PMID: 16000727 PMCID: PMC1489810 DOI: 10.1099/mic.0.27649-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella enterica serovar Typhimurium (S. Typhimurium) elicits the starvation-stress response (SSR) due to starvation for an essential nutrient, e.g. a carbon/energy source (C-source). As part of the SSR, the alternative sigma factor sigma(E) is activated and induced. The authors suspect that this activation is, in part, triggered by changes in the S. Typhimurium cell envelope occurring during the adaptation from growth to carbon/energy starvation (C-starvation), and resulting in an increased need for sigma(E)-regulated factors involved in the proper folding and assembly of newly synthesized proteins destined for this extracytoplasmic compartment. This led to the hypothesis that a sigma(E) activation signal might arise during C-source shifts that cause the induction of proteins localized to the extracytoplasmic compartment, i.e. the outer membrane or periplasm, of the cell. To test this hypothesis, cultures were grown in minimal medium containing enough glucose to reach mid-exponential-phase, plus a non-limiting amount of a secondary 'less-preferred' but utilizable carbon/energy source. The sigma(E) activity was then monitored using plasmids carrying rpoEP1- and rpoEP2-lacZ transcriptional fusions, which exhibit sigma(E)-independent and -dependent lacZ expression, respectively. The secondary C-sources maltose, succinate and citrate, which have extracytoplasmic components involved in their utilization (e.g. LamB), resulted in a discernible diauxic lag period and a sustained increase in sigma(E) activity. Growth transition from glucose to other utilizable phosphotransferase (PTS) and non-PTS C-sources, such as trehalose, mannose, mannitol, fructose, glycerol, d-galactose or l-arabinose, did not cause a discernible diauxic lag period or a sustained increase in sigma(E) activity. Interestingly, a shift from glucose to melibiose, which does not use an extracytoplasmic-localized protein for uptake, did cause an observable diauxic lag period but did not result in a sustained increase in sigma(E) activity. In addition, overexpression of LamB from an arabinose-inducible promoter leads to a significant increase in sigma(E) activity in the absence of a glucose to maltose shift or C-starvation. Furthermore, a DeltalamB : : Omega-Km(r) mutant, lacking the LamB maltoporin, exhibited an approximately twofold reduction in the sustained sigma(E) activity observed during a glucose to maltose shift, again supporting the hypothesis. Interestingly, the LamB protein lacks the typical Y-X-F terminal tripeptide of the OmpC-like peptides that activate DegS protease activity leading to sigma(E) activation. It does, however, possess a terminal pentapeptide (Q-M-E-I-W-W) that may function as a ligand for a putative class II PDZ-binding site. The authors therefore propose that the sigma(E) regulon of S. Typhimurium not only is induced in response to deleterious environmental conditions, but also plays a role in the adaptation of cells to new growth conditions that necessitate changes in the extracytoplasmic compartment of the cell, which may involve alternative signal recognition and activation pathways that are independent of DegS.
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Affiliation(s)
- William J. Kenyon
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
| | - Sheena M. Thomas
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
| | - Erin Johnson
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
| | - Mark J. Pallen
- Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, Medical School, University of Birmingham, Birmingham B15 2TT, UK
| | - Michael P. Spector
- Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA
- Correspondence Michael P. Spector,
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Becker LA, Bang IS, Crouch ML, Fang FC. Compensatory role of PspA, a member of the phage shock protein operon, in rpoE mutant Salmonella enterica serovar Typhimurium. Mol Microbiol 2005; 56:1004-16. [PMID: 15853886 DOI: 10.1111/j.1365-2958.2005.04604.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sigma(E) is an alternative sigma factor that responds to and ameliorates extracytoplasmic stress. In Salmonella enterica serovar Typhimurium (S. Typhimurium), sigma(E) is required for oxidative stress resistance, stationary-phase survival and virulence in mice. Microarray analysis of stationary-phase gene expression in rpoE mutant bacteria revealed a dramatic increase in expression of pspA, a member of the phage shock protein (psp) operon. The psp operon can be induced by filamentous bacteriophages or by perturbations of protein secretion, and is believed to facilitate the maintenance of proton motive force (PMF). We hypothesized that increased pspA expression may represent a compensatory response to the loss of sigma(E) function. Increased pspA expression was confirmed in rpoE mutant Salmonella and also observed in a mutant lacking the F(1)F(0) ATPase. Alternatively, expression of pspA could be induced by exposure to CCCP, a protonophore that disrupts PMF. An rpoE pspA double mutant strain was found to have a stationary-phase survival defect more pronounced than that of isogenic strains harbouring single mutations. The double mutant strains were also more susceptible to killing by CCCP or by a bactericidal/permeability-increasing protein (BPI)-derived anti-microbial peptide. Using fluorescence ratio imaging, differences were observed in the Deltapsi of wild-type and rpoE or pspA mutant bacteria. These findings suggest that pspA expression in S. Typhimurium is induced by alterations in PMF and a functional sigma(E) regulon is essential for the maintenance of PMF.
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Affiliation(s)
- Lynne A Becker
- Departments of Laboratory Medicine and Microbiology, University of Washington School of Medicine, Seattle, WA 98195, USA
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36
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Rychlik I, Barrow PA. Salmonella stress management and its relevance to behaviour during intestinal colonisation and infection. FEMS Microbiol Rev 2005; 29:1021-40. [PMID: 16023758 DOI: 10.1016/j.femsre.2005.03.005] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 03/04/2005] [Accepted: 03/30/2005] [Indexed: 01/13/2023] Open
Abstract
The enteric pathogen Salmonella enterica is exposed to a number of stressful environments during its life cycle within and outside its various hosts. During intestinal colonisation Salmonella is successively exposed to acid pH in the stomach, to the detergent-like activity of bile, to decreasing oxygen supply, to the presence of multiple metabolites produced by the normal gut microflora and finally it is exposed to cationic antimicrobial peptides present on the surface of epithelial cells. There are four major regulators controlling relevant stress responses in Salmonella, namely RpoS, PhoPQ, Fur and OmpR/EnvZ. Except for Fur, inactivation of genes encoding the other stress regulators results in attenuated virulence and such mutants can therefore be considered as vaccine candidates. In contrast, a decrease in oxygen supply monitored by Fnr and ArcAB, or oxidative stress controlled by OxyR and SoxRS is not regarded as a stress associated with host colonisation since inactivation of either of these systems does not result in reductions in colonisation. The role of quorum-sensing through luxS and sdiA is also considered as a regulator of virulence and colonisation.
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Affiliation(s)
- Ivan Rychlik
- Veterinary Research Institute, Hudcova 70, 621 32 Brno, Czech Republic.
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37
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Bang IS, Frye JG, McClelland M, Velayudhan J, Fang FC. Alternative sigma factor interactions inSalmonella: σEand σHpromote antioxidant defences by enhancing σSlevels. Mol Microbiol 2005; 56:811-23. [PMID: 15819634 DOI: 10.1111/j.1365-2958.2005.04580.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hierarchical interactions between alternative sigma factors control sequential gene expression in Gram-positive bacteria, whereas alternative sigma factors in Gram-negative bacteria are generally regarded to direct expression of discrete gene subsets. In Salmonella enterica serovar Typhimurium (S. Typhimurium), sigma(E) responds to extracytoplasmic stress, whereas sigma(H) responds to heat shock and sigma(S) is induced during nutrient limitation. Deficiency of sigma(E), sigma(H) or sigma(S) increases S. Typhimurium susceptibility to oxidative stress, but an analysis of double and triple mutants suggested that antioxidant actions of sigma(E) and sigma(H) might be dependent on sigma(S). Transcriptional profiling of mutant Salmonella lacking sigma(E) revealed reduced expression of genes dependent on sigma(H) and sigma(S) in addition to sigma(E). Further investigation demonstrated that sigma(E) augments sigma(S) levels during stationary phase via enhanced expression of sigma(H) and the RNA-binding protein Hfq, leading to increased expression of sigma(S)-dependent genes and enhanced resistance to oxidative stress. Maximal expression of the sigma(S)-regulated gene katE required sigma(E) in Salmonella-infected macrophages as well as stationary-phase cultures. Interactions between alternative sigma factors permit the integration of diverse stress signals to produce coordinated genetic responses.
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Affiliation(s)
- Iel-Soo Bang
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195, USA
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38
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Miticka H, Rezuchova B, Homerova D, Roberts M, Kormanec J. Identification of nucleotides critical for activity of the Ï E-dependent rpoEp3promoter in Salmonella entericaserovar Typhimurium. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09760.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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39
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Amzallag GN. Adaptive changes in bacteria: a consequence of nonlinear transitions in chromosome topology? J Theor Biol 2004; 229:361-9. [PMID: 15234203 DOI: 10.1016/j.jtbi.2004.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2003] [Revised: 01/11/2004] [Accepted: 04/06/2004] [Indexed: 10/26/2022]
Abstract
Adaptive changes in bacteria are generally considered to result from random mutations selected by the environment. This interpretation is challenged by the non-randomness of genomic changes observed following ageing or starvation in bacterial colonies. A theory of adaptive targeting of sequences for enzymes involved in DNA transactions is proposed here. It is assumed that the sudden leakage of cAMP consecutive to starvation induces a rapid drop in the ATP/ADP ratio that inactivates the homeostasis in control of the level of DNA supercoiling. This phase change enables the emergence of local modifications in chromosome topology in relation to the missing metabolites, a first stage in expression of an adaptive status in which DNA transactions are induced. The nonlinear perspective proposed here is homologous to that already suggested for adaptation of pluricellular organisms during their development. In both cases, phases of robustness in regulation networks for genetic expression are interspaced by critical periods of breakdown of the homeostatic regulations during which, through isolation of nodes from a whole network, specific changes with adaptive value may locally occur.
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Affiliation(s)
- G N Amzallag
- The Judea Center for Research and Development, Carmel 90404, Israel.
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40
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Bischoff M, Dunman P, Kormanec J, Macapagal D, Murphy E, Mounts W, Berger-Bächi B, Projan S. Microarray-based analysis of the Staphylococcus aureus sigmaB regulon. J Bacteriol 2004; 186:4085-99. [PMID: 15205410 PMCID: PMC421609 DOI: 10.1128/jb.186.13.4085-4099.2004] [Citation(s) in RCA: 310] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 03/18/2004] [Indexed: 01/30/2023] Open
Abstract
Microarray-based analysis of the transcriptional profiles of the genetically distinct Staphylococcus aureus strains COL, GP268, and Newman indicate that a total of 251 open reading frames (ORFs) are influenced by sigmaB activity. While sigmaB was found to positively control 198 genes by a factor of > or =2 in at least two of the three genetic lineages analyzed, 53 ORFs were repressed in the presence of sigmaB. Gene products that were found to be influenced by sigmaB are putatively involved in all manner of cellular processes, including cell envelope biosynthesis and turnover, intermediary metabolism, and signaling pathways. Most of the genes and/or operons identified as upregulated by sigmaB were preceded by a nucleotide sequence that resembled the sigmaB consensus promoter sequence of Bacillus subtilis. A conspicuous number of virulence-associated genes were identified as regulated by sigmaB activity, with many adhesins upregulated and prominently represented in this group, while transcription of various exoproteins and toxins were repressed. The data presented here suggest that the sigmaB of S. aureus controls a large regulon and is an important modulator of virulence gene expression that is likely to act conversely to RNAIII, the effector molecule of the agr locus. We propose that this alternative transcription factor may be of importance for the invading pathogen to fine-tune its virulence factor production in response to changing host environments.
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Affiliation(s)
- Markus Bischoff
- Department of Medical Microbiology, University of Zurich, CH-8028 Zurich, Switzerland.
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41
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Miticka H, Rowley G, Rezuchova B, Homerova D, Humphreys S, Farn J, Roberts M, Kormanec J. Transcriptional analysis of therpoEgene encoding extracytoplasmic stress response sigma factor ÏEinSalmonella entericaserovar Typhimurium. FEMS Microbiol Lett 2003; 226:307-14. [PMID: 14553927 DOI: 10.1016/s0378-1097(03)00600-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The rpoE gene of Salmonella enterica serovar Typhimurium (S. Typhimurium), which encodes the extracytoplasmic stress response sigma factor sigmaE, is critically important for the virulence of S. Typhimurium. We analysed expression of rpoE by wild-type and mutant bacteria grown in different conditions by S1-nuclease mapping using RNA, and using in vivo reporter gene fusions. Three promoters, rpoEp1, rpoEp2 and rpoEp3, were located upstream of the S. Typhimurium rpoE gene. The promoters were differentially expressed during growth and under several stress conditions including cold shock. Expression from the rpoEp3 promoter was absent in an S. Typhimurium rpoE mutant, demonstrating its dependence upon sigmaE. The level of mRNA corresponding to rpoEp3 was also higher in a cpxR mutant, indicating a negative regulation of the promoter by the Cpx system. Using this rpoE-dependent promoter, we optimised a two-plasmid system for identification of promoters recognised by S. Typhimurium sigmaE. The rpoEp3 promoter was active in the Escherichia coli two-plasmid system and has an identical transcription start point as in S. Typhimurium but only after induction of S. Typhimurium rpoE expression.
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Affiliation(s)
- Henrieta Miticka
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republic
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42
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Davies RH, Breslin M. Persistence of Salmonella enteritidis phage type 4 in the environment and arthropod vectors on an empty free-range chicken farm. Environ Microbiol 2003; 5:79-84. [PMID: 12558590 DOI: 10.1046/j.1462-2920.2003.00387.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The persistence of S. Enteritidis PT4 was studied on a free-range breeding chicken farm which had been depopulated following identification of the organism in breeding birds. The site was sampled periodically for 26 months after depopulation and the organism was found to persist in litter, dried faeces and feed, but not in dust within empty poultry houses, for the whole of that period. Salmonella Enteritidis PT4 was also found in soil samples after 8 months but not 13 months and in faeces from wild mice, foxes and cats but not wild birds or badgers. The organism was also found in adult and larval forms of ground beetles and centipedes. Addition of pullets to a contaminated pen or inclusion of contaminated litter, feed or beetles/larvae to feed did not result in acquisition of infection by birds.
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Affiliation(s)
- Robert H Davies
- Department of Bacterial Diseases, Veterinary Laboratories Agency-Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
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