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Long DR, Holmes EA, Lo HY, Penewit K, Almazan J, Hodgson T, Berger NF, Bishop ZH, Lewis JD, Waalkes A, Wolter DJ, Salipante SJ. Clinical and in vitro models identify distinct adaptations enhancing Staphylococcus aureus pathogenesis in human macrophages. PLoS Pathog 2024; 20:e1012394. [PMID: 38991026 PMCID: PMC11265673 DOI: 10.1371/journal.ppat.1012394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 07/23/2024] [Accepted: 07/04/2024] [Indexed: 07/13/2024] Open
Abstract
Staphylococcus aureus is a facultative intracellular pathogen of human macrophages, which facilitates chronic infection. The genotypes, pathways, and mutations influencing that phenotype remain incompletely explored. Here, we used two distinct strategies to ascertain S. aureus gene mutations affecting pathogenesis in macrophages. First, we analyzed isolates collected serially from chronic cystic fibrosis (CF) respiratory infections. We found that S. aureus strains evolved greater macrophage invasion capacity during chronic human infection. Bacterial genome-wide association studies (GWAS) identified 127 candidate genes for which mutation was significantly associated with macrophage pathogenesis in vivo. In parallel, we passaged laboratory S. aureus strains in vitro to select for increased infection of human THP-1 derived macrophages, which identified 15 candidate genes by whole-genome sequencing. Functional validation of candidate genes using isogenic transposon mutant knockouts and CRISPR interference (CRISPRi) knockdowns confirmed virulence contributions from 37 of 39 tested genes (95%) implicated by in vivo studies and 7 of 10 genes (70%) ascertained from in vitro selection, with one gene in common to the two strategies. Validated genes included 17 known virulence factors (39%) and 27 newly identified by our study (61%), some encoding functions not previously associated with macrophage pathogenesis. Most genes (80%) positively impacted macrophage invasion when disrupted, consistent with the phenotype readily arising from loss-of-function mutations in vivo. This work reveals genes and mechanisms that contribute to S. aureus infection of macrophages, highlights differences in mutations underlying convergent phenotypes arising from in vivo and in vitro systems, and supports the relevance of S. aureus macrophage pathogenesis during chronic respiratory infection in CF. Additional studies will be needed to illuminate the exact mechanisms by which implicated mutations affect their phenotypes.
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Affiliation(s)
- Dustin R. Long
- Division of Critical Care Medicine, Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Elizabeth A. Holmes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Hsin-Yu Lo
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Kelsi Penewit
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Jared Almazan
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Taylor Hodgson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Nova F. Berger
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Zoe H. Bishop
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Janessa D. Lewis
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Adam Waalkes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Daniel J. Wolter
- Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, United States of America
| | - Stephen J. Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, United States of America
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Wessler S, Posselt G. Bacterial Proteases in Helicobacter pylori Infections and Gastric Disease. Curr Top Microbiol Immunol 2023; 444:259-277. [PMID: 38231222 DOI: 10.1007/978-3-031-47331-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Helicobacter pylori (H. pylori) proteases have become a major focus of research in recent years, because they not only have an important function in bacterial physiology, but also directly alter host cell functions. In this review, we summarize recent findings on extracellular H. pylori proteases that target host-derived substrates to facilitate bacterial pathogenesis. In particular, the secreted H. pylori collagenase (Hp0169), the metalloprotease Hp1012, or the serine protease High temperature requirement A (HtrA) are of great interest. Specifically, various host cell-derived substrates were identified for HtrA that directly interfere with the gastric epithelial barrier allowing full pathogenesis. In light of increasing antibiotic resistance, the development of inhibitory compounds for extracellular proteases as potential targets is an innovative field that offers alternatives to existing therapies.
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Affiliation(s)
- Silja Wessler
- Department of Biosciences and Medical Biology, Laboratory for Microbial Infection and Cancer, Paris-Lodron University of Salzburg, Salzburg, Austria.
- Cancer Cluster Salzburg and Allergy-Cancer-BioNano Research Centre, Salzburg, Austria.
| | - Gernot Posselt
- Department of Biosciences and Medical Biology, Laboratory for Microbial Infection and Cancer, Paris-Lodron University of Salzburg, Salzburg, Austria
- Cancer Cluster Salzburg and Allergy-Cancer-BioNano Research Centre, Salzburg, Austria
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3
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Yao X, Xiao S, Zhou L. Integrative proteomic and metabolomic analyses reveal the mechanism by which bismuth enables Helicobacter pylori eradication. Helicobacter 2021; 26:e12846. [PMID: 34414638 DOI: 10.1111/hel.12846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 01/08/2023]
Abstract
BACKGROUND Bismuth-based drugs are used to treat Helicobacter pylori infection; however, the antibacterial activity of bismuth, especially against H. pylori, has not been fully elucidated. In this study, the mechanisms by which bismuth exerts its detrimental effects on H. pylori were evaluated. Methods Six H. pylori strains isolated from different patients were cultured with or without bismuth; proteins and metabolites differentially expressed in these two sets of bacteria were detected via data independent acquisition proteomic and gas chromatography-mass spectrometry metabolic approaches, respectively. Gene ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes database were used to identity pathway enrichment. RESULTS Bismuth inhibited H. pylori growth in vitro via the following mechanisms: downregulation of virulence proteins CagA and VacA; disruption of flagella assembly responsible for bacterial colonization; and inhibition of antioxidant enzymes, including catalase, catalase-related peroxidase, and superoxide dismutase. Diverse metabolic pathways related to growth and RNA translation in H. pylori were disrupted by bismuth. Bismuth treatment impaired many biological processes in H. pylori, including antioxidant response and purine, pyrimidine, amino acid, and carbon metabolism. Conclusions The findings of this study suggest that motility, virulence factors CagA and VacA, antioxidant defense system, and many important metabolic pathways associated with bacterial growth, including nucleotide and amino acid metabolism and translation in H. pylori, are inhibited by bismuth. This study provides novel insights into the mechanism by which bismuth eradicates H. pylori upon being incorporated into quadruple therapy.
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Affiliation(s)
- Xingyu Yao
- Department of Gastroenterology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Helicobacter pylori Infection and Upper Gastrointestinal Diseases, Peking University Third Hospital, Beijing, China
| | - Shiyu Xiao
- Department of Gastroenterology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Helicobacter pylori Infection and Upper Gastrointestinal Diseases, Peking University Third Hospital, Beijing, China
| | - Liya Zhou
- Department of Gastroenterology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Helicobacter pylori Infection and Upper Gastrointestinal Diseases, Peking University Third Hospital, Beijing, China
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Abstract
By assisting in the proteolysis, disaggregation and refolding of the aggregated proteins, Caseinolytic proteases (Clps) enhance the cellular survival under stress conditions. In the current study, comparative roles of two such Clps, ClpA (involved in proteolysis) and ClpB (involved in protein disaggregation and refolding) in the survival of Salmonella Typhimurium (S. Typhimurium) under different stresses and in virulence have been investigated. clpA and clpB gene deletion mutant strains (∆clpA and ∆clpB) of S. Typhimurium have been hypersensitive to 42 °C, HOCl and paraquat. However, the ∆clpB strain was comparatively much more susceptible (p < 0.001) to the above stresses than ∆clpA strain. ∆clpB strain also showed reduced survival (p < 0.001) in poultry macrophages. The hypersusceptibilities of ∆clpB strain to oxidants and macrophages were restored in plasmid based complemented (∆clpB + pclpB) strain. Further, the ∆clpB strain was defective for colonization in the poultry caecum and showed decreased dissemination to the spleen and liver. Our findings suggest that the role of ClpB is more important than the role of ClpA for the survival of S. Typhimurium under stress and colonization in chickens.
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Dong SL, Hu WL, Ge YM, Ojcius DM, Lin X, Yan J. A leptospiral AAA+ chaperone-Ntn peptidase complex, HslUV, contributes to the intracellular survival of Leptospira interrogans in hosts and the transmission of leptospirosis. Emerg Microbes Infect 2017; 6:e105. [PMID: 29184154 PMCID: PMC5717094 DOI: 10.1038/emi.2017.93] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/17/2017] [Accepted: 09/24/2017] [Indexed: 12/13/2022]
Abstract
Leptospirosis caused by Leptospira is a zoonotic disease of global importance but it is considered as an emerging or re-emerging infectious disease in many areas in the world. Until now, the mechanisms about pathogenesis and transmission of Leptospira remains poorly understood. As eukaryotic and prokaryotic proteins can be denatured in adverse environments and chaperone-protease/peptidase complexes degrade these harmful proteins, we speculate that infection may also cause leptospiral protein denaturation, and the HslU and HslV proteins of L. interrogans may compose a complex to degrade denatured proteins that enhances leptospiral survival in hosts. Here we show that leptospiral HslUV is an ATP-dependent chaperone-peptidase complex containing ATPase associated with various cellular activity (AAA+) and N-terminal nucleophile (Ntn) hydrolase superfamily domains, respectively, which hydrolyzed casein and chymotrypsin-like substrates, and this hydrolysis was blocked by threonine protease inhibitors. The infection of J774A.1 macrophages caused the increase of leptospiral denatured protein aggresomes, but more aggresomes accumulated in hslUV gene-deleted mutant. The abundant denatured leptospiral proteins are involved in ribosomal structure, flagellar assembly, two-component signaling systems and transmembrane transport. Compared to the wild-type strain, infection of cells in vitro with the mutant resulted in a higher number of dead leptospires, less leptospiral colony-forming units and lower growth ability, but also displayed a lower half lethal dose, attenuated histopathological injury and decreased leptospiral loading in lungs, liver, kidneys, peripheral blood and urine in hamsters. Therefore, our findings confirmed that HslUV AAA+ chaperone-Ntn peptidase complex of L. interrogans contributes to leptospiral survival in hosts and transmission of leptospirosis.
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Affiliation(s)
- Shi-Lei Dong
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.,Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, Zhejiang 310013, China
| | - Wei-Lin Hu
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China
| | - Yu-Mei Ge
- Department of Clinical Laboratory, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang 310014, China
| | - David M Ojcius
- Department of Biomedical Sciences, University of the Pacific, Arthur Dugoni School of Dentistry, San Francisco, CA 94103, USA
| | - Xu'ai Lin
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China
| | - Jie Yan
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China
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6
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Gharibi S, Falsafi T, Alebouyeh M, Farzi N, Vaziri F, Zali MR. Relationship between histopathological status of the Helicobacter pylori infected patients and proteases of H. pylori in isolates carrying diverse virulence genotypes. Microb Pathog 2017. [PMID: 28629725 DOI: 10.1016/j.micpath.2017.06.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Helicobacter pylori is the main cause of several gastroduodenal diseases in Humans. Among various virulence factors of H. pylori, proteases may also be involved in its pathogenicity. In this study, relationship between proteolytic activity of H. pylori strains and histopathological changes of the stomach was investigated in the patients infected with strains carrying diverse virulence factors. H. pylori strains were isolated from the biopsies of 116 patients who referred to hospital for their gastroduodenal disorders, in Tehran, Iran. Biopsies were sent to microbiology and pathology laboratories for further analysis. All the suspected grown colonies were characterized by both biochemical tests and polymerase chain reaction (PCR). Presence of seven protease genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350 and hp1435, and distinct allelic variants of H. pylori virulence factors, cagA, vacA, iceA, babA2 and sabA, were analyzed in each strain. Protease activity of the strains was assessed using spectrophotometric assay. Furthermore, association between diversity in protease genes and virulence genes, protease activity, as well as pathological changes was estimated statistically. Proteases genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350, hp1435, were detected among 100%, 100%, 98%, 98%, 98%, 98%, and 8% of fifty H. pylori strains isolated from the patients, respectively. Status of cagA, vacA s1, vacA s2, vacA m1, vacA m2, iceA1, iceA2, babA2 and sabA genes in isolates were 64%, 68%, 30%, 26%, 74%, 48%, 52%, 100%, and 96%, respectively. Predominant (84%) combined status for protease genes was: htrA/clpP/hp0169/hp1012/hp0382/hP1350/hp1435, while the prevalent combined status (16%) for virulence genes was: cagA+/vacA s1m2/iceA1+/sabA+/babA2+. Although most of the strains (91.4%) presented moderate protease activity in vitro, lowest activity was measured in strains isolated from the patients with chronic gastritis (4.25%). Present study provide the new data on diversity of protease genes in H. pylori, as well as the proteolytic activity of these genes in H. pylori strains from the sick patients. Presence of significant association between lower protease activity of the strains and mildness of the pathological changes propose involvement of these proteases in the pathogenesis of H. pylori in vivo.
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Affiliation(s)
- Somayyeh Gharibi
- Department of Microbiology, Faculty of Biological Science, Alzahra University, Tehran, Iran
| | - Tahereh Falsafi
- Department of Microbiology, Faculty of Biological Science, Alzahra University, Tehran, Iran.
| | - Masoud Alebouyeh
- Foodborne and Waterborne Disease Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Nastaran Farzi
- Foodborne and Waterborne Disease Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farzam Vaziri
- Mycobacteriology and Pulmonary Research Department, Pasteur Institute of Iran, Iran
| | - Mohamad Reza Zali
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Pang M, Lin X, Liu J, Guo C, Gao S, Du H, Lu C, Liu Y. Identification of Aeromonas hydrophila Genes Preferentially Expressed after Phagocytosis by Tetrahymena and Involvement of Methionine Sulfoxide Reductases. Front Cell Infect Microbiol 2016; 6:199. [PMID: 28083518 PMCID: PMC5183988 DOI: 10.3389/fcimb.2016.00199] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Accepted: 12/13/2016] [Indexed: 01/03/2023] Open
Abstract
Free-living protozoa affect the survival and virulence evolution of pathogens in the environment. In this study, we explored the fate of Aeromonas hydrophila when co-cultured with the bacteriovorous ciliate Tetrahymena thermophila and investigated bacterial gene expression associated with the co-culture. Virulent A. hydrophila strains were found to have ability to evade digestion in the vacuoles of this protozoan. In A. hydrophila, a total of 116 genes were identified as up-regulated following co-culture with T. thermophila by selective capture of transcribed sequences (SCOTS) and comparative dot-blot analysis. A large proportion of these genes (42/116) play a role in metabolism, and some of the genes have previously been characterized as required for bacterial survival and replication within macrophages. Then, we inactivated the genes encoding methionine sulfoxide reductases, msrA, and msrB, in A. hydrophila. Compared to the wild-type, the mutants ΔmsrA and ΔmsrAB displayed significantly reduced resistance to predation by T. thermophila, and 50% lethal dose (LD50) determinations in zebrafish demonstrated that both mutants were highly attenuated. This study forms a solid foundation for the study of mechanisms and implications of bacterial defenses.
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Affiliation(s)
- Maoda Pang
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural UniversityNanjing, China; Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Institute of Food Safety, Jiangsu Academy of Agricultural SciencesNanjing, China
| | - Xiaoqin Lin
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Jin Liu
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Changming Guo
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Shanshan Gao
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Hechao Du
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Chengping Lu
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yongjie Liu
- Department of Preventive Veterinary, College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
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8
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Hanafi A, Lee WC, Loke MF, Teh X, Shaari A, Dinarvand M, Lehours P, Mégraud F, Leow AHR, Vadivelu J, Goh KL. Molecular and Proteomic Analysis of Levofloxacin and Metronidazole Resistant Helicobacter pylori. Front Microbiol 2016; 7:2015. [PMID: 28018334 PMCID: PMC5157799 DOI: 10.3389/fmicb.2016.02015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 12/01/2016] [Indexed: 12/19/2022] Open
Abstract
Antibiotic resistance in bacteria incurs fitness cost, but compensatory mechanisms may ameliorate the cost and sustain the resistance even under antibiotics-free conditions. The aim of this study was to determine compensatory mechanisms of antibiotic resistance in H. pylori. Five strains of levofloxacin-sensitive H. pylori were induced in vitro to develop resistance. In addition, four pairs of metronidazole-sensitive and -resistant H. pylori strains were isolated from patients carrying dual H. pylori populations that consist of both sensitive and resistant phenotypes. Growth rate, virulence and biofilm-forming ability of the sensitive and resistant strains were compared to determine effects of compensatory response. Proteome profiles of paired sensitive and resistant strains were analyzed by liquid chromatography/mass spectrophotometry (LC/MS). Although there were no significant differences in growth rate between sensitive and resistant pairs, bacterial virulence (in terms of abilities to induce apoptosis and form biofilm) differs from pair to pair. These findings demonstrate the complex and strain-specific phenotypic changes in compensation for antibiotics resistance. Compensation for in vitro induced levofloxacin resistance involving mutations of gyrA and gyrB was functionally random. Furthermore, higher protein translation and non-functional protein degradation capabilities in naturally-occuring dual population metronidazole sensitive-resistant strains may be a possible alternative mechanism underlying resistance to metronidazole without mutations in rdxA and frxA. This may explain the lack of mutations in target genes in ~10% of metronidazole resistant strains.
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Affiliation(s)
- Aimi Hanafi
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Woon Ching Lee
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Mun Fai Loke
- Department of Medical Microbiology, Faculty of Medicine, University of MalayaKuala Lumpur, Malaysia; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of SingaporeSingapore, Singapore
| | - Xinsheng Teh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Ain Shaari
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Mojdeh Dinarvand
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Philippe Lehours
- Laboratoire de Bactériologie, Université de BordeauxBordeaux, France; Institut National de la Santé et de la Recherche Médicale U853Bordeaux, France
| | - Francis Mégraud
- Laboratoire de Bactériologie, Université de BordeauxBordeaux, France; Institut National de la Santé et de la Recherche Médicale U853Bordeaux, France
| | - Alex Hwong Ruey Leow
- Department of Medicine, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
| | - Khean Lee Goh
- Department of Medicine, Faculty of Medicine, University of Malaya Kuala Lumpur, Malaysia
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The Protease Locus of Francisella tularensis LVS Is Required for Stress Tolerance and Infection in the Mammalian Host. Infect Immun 2016; 84:1387-1402. [PMID: 26902724 DOI: 10.1128/iai.00076-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 02/12/2016] [Indexed: 02/05/2023] Open
Abstract
Francisella tularensis is the causative agent of tularemia and a category A potential agent of bioterrorism, but the pathogenic mechanisms of F. tularensis are largely unknown. Our previous transposon mutagenesis screen identified 95 lung infectivity-associated F. tularensis genes, including those encoding the Lon and ClpP proteases. The present study validates the importance of Lon and ClpP in intramacrophage growth and infection of the mammalian host by using unmarked deletion mutants of the F. tularensis live vaccine strain (LVS). Further experiments revealed that lon and clpP are also required for F. tularensis tolerance to stressful conditions. A quantitative proteomic comparison between heat-stressed LVS and the isogenic Lon-deficient mutant identified 29 putative Lon substrate proteins. The follow-up protein degradation experiments identified five substrates of the F. tularensis Lon protease (FTL578, FTL663, FTL1217, FTL1228, and FTL1957). FTL578 (ornithine cyclodeaminase), FTL663 (heat shock protein), and FTL1228 (iron-sulfur activator complex subunit SufD) have been previously described as virulence-associated factors in F. tularensis Identification of these Lon substrates has thus provided important clues for further understanding of the F. tularensis stress response and pathogenesis. The high-throughput approach developed in this study can be used for systematic identification of the Lon substrates in other prokaryotic and eukaryotic organisms.
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10
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Schmitz KR, Carney DW, Sello JK, Sauer RT. Crystal structure of Mycobacterium tuberculosis ClpP1P2 suggests a model for peptidase activation by AAA+ partner binding and substrate delivery. Proc Natl Acad Sci U S A 2014; 111:E4587-95. [PMID: 25267638 PMCID: PMC4217457 DOI: 10.1073/pnas.1417120111] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Caseinolytic peptidase P (ClpP), a double-ring peptidase with 14 subunits, collaborates with ATPases associated with diverse activities (AAA+) partners to execute ATP-dependent protein degradation. Although many ClpP enzymes self-assemble into catalytically active homo-tetradecamers able to cleave small peptides, the Mycobacterium tuberculosis enzyme consists of discrete ClpP1 and ClpP2 heptamers that require a AAA+ partner and protein-substrate delivery or a peptide agonist to stabilize assembly of the active tetradecamer. Here, we show that cyclic acyldepsipeptides (ADEPs) and agonist peptides synergistically activate ClpP1P2 by mimicking AAA+ partners and substrates, respectively, and determine the structure of the activated complex. Our studies establish the basis of heteromeric ClpP1P2 assembly and function, reveal tight coupling between the conformations of each ring, show that ADEPs bind only to one ring but appear to open the axial pores of both rings, provide a foundation for rational drug development, and suggest strategies for studying the roles of individual ClpP1 and ClpP2 rings in Clp-family proteolysis.
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Affiliation(s)
- Karl R Schmitz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; and
| | - Daniel W Carney
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Jason K Sello
- Department of Chemistry, Brown University, Providence, RI 02912
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; and
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11
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Tu IF, Liao JH, Yang FL, Lin NT, Chan HL, Wu SH. Lon protease affects the RdxA nitroreductase activity and metronidazole susceptibility in Helicobacter pylori. Helicobacter 2014; 19:356-66. [PMID: 24834789 DOI: 10.1111/hel.12140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The lon gene of Helicobacter pylori strains is constitutively expressed during growth. However, virtually nothing is understood concerning the role of Lon in H. pylori. This study examined the function and physiological role of Lon in H. pylori (HpLon) using a trapping approach to identify putative Lon binding partners in the bacterium. MATERIALS AND METHODS Protease-deficient Lon was expressed and served as the bait in trapping approach to capture the interacting partners in H. pylori. The antibiotic susceptibility of wild-type and lon derivative mutants was determined by the E test trips and the disc diffusion assay. The effect of HpLon on RdxA activity was detected the change in NADPH oxidation and metronidazole reduction by spectrophotometer. RESULTS Lon in Helicobacter pylori (HpLon) interacting partners are mostly associated with metronidazole activation. lon mutant presents more susceptible to metronidazole than that of the wild type, and this phenotype is recovered by complementation of the wild-type Lon. We found that the ATPases associated with a variety of cellular activities (AAA(+) ) module of HpLon causes a decrease in both NADPH oxidase and Mtz reductase activity in RdxA, a major Mtz-activating enzyme in H. pylori. CONCLUSION Metronidazole resistance of H. pylori causes the serious medical problem worldwide. In this study, HpLon is involved in metronidazole susceptibility among H. pylori strains. We provide the evidence that HpLon alters RdxA activity in vitro. The decrease in metronidazole activation caused by HpLon is possibly prior to accumulate mutation in rdxA gene before the metronidazole-resistant strains to be occurred.
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Affiliation(s)
- I-Fan Tu
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, 300, Taiwan
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Campbell AG, Schwientek P, Vishnivetskaya T, Woyke T, Levy S, Beall CJ, Griffen A, Leys E, Podar M. Diversity and genomic insights into the uncultured Chloroflexi from the human microbiota. Environ Microbiol 2014; 16:2635-43. [PMID: 24738594 PMCID: PMC4149597 DOI: 10.1111/1462-2920.12461] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Many microbial phyla that are widely distributed in open environments have few or no representatives within animal-associated microbiota. Among them, the Chloroflexi comprises taxonomically and physiologically diverse lineages adapted to a wide range of aquatic and terrestrial habitats. A distinct group of uncultured chloroflexi related to free-living anaerobic Anaerolineae inhabits the mammalian gastrointestinal tract and includes low-abundance human oral bacteria that appear to proliferate in periodontitis. Using a single-cell genomics approach, we obtained the first draft genomic reconstruction for these organisms and compared their inferred metabolic potential with free-living chloroflexi. Genomic data suggest that oral chloroflexi are anaerobic heterotrophs, encoding abundant carbohydrate transport and metabolism functionalities, similar to those seen in environmental Anaerolineae isolates. The presence of genes for a unique phosphotransferase system and N-acetylglucosamine metabolism suggests an important ecological niche for oral chloroflexi in scavenging material from lysed bacterial cells and the human tissue. The inferred ability to produce sialic acid for cell membrane decoration may enable them to evade the host defence system and colonize the subgingival space. As with other low abundance but persistent members of the microbiota, discerning community and host factors that influence the proliferation of oral chloroflexi may help understand the emergence of oral pathogens and the microbiota dynamics in health and disease states.
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Affiliation(s)
- Alisha G. Campbell
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, TN, USA
| | | | | | - Tanja Woyke
- Joint Genome Institute, Walnut Creek, California, USA
| | - Shawn Levy
- Hudson Alpha Institute for Biotechnology, Huntsville, AL, USA
| | | | - Ann Griffen
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Eugene Leys
- College of Dentistry, The Ohio State University, Columbus, OH, USA
| | - Mircea Podar
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, TN, USA
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Knudsen GM, Nielsen MB, Thomsen LE, Aabo S, Rychlik I, Olsen JE. The role of ClpP, RpoS and CsrA in growth and filament formation of Salmonella enterica serovar Typhimurium at low temperature. BMC Microbiol 2014; 14:208. [PMID: 25123657 PMCID: PMC4236599 DOI: 10.1186/s12866-014-0208-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/21/2014] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Salmonellae are food-borne pathogens of great health and economic importance. To pose a threat to humans, Salmonellae normally have to cope with a series of stressful conditions in the food chain, including low temperature. In the current study, we evaluated the importance of the Clp proteolytic complex and the carbon starvation protein, CsrA, for the ability of Salmonella Typhimurium to grow at low temperature. RESULTS A clpP mutant was severely affected in growth and formed pin point colonies at 10°C. Contrary to this, rpoS and clpP/rpoS mutants were only slightly affected. The clpP mutant formed cold resistant suppressor mutants at a frequency of 2.5 × 10(-3) and these were found not to express RpoS. Together these results indicated that the impaired growth of the clpP mutant was caused by high level of RpoS. Evaluation by microscopy of the clpP mutant revealed that it formed filamentous cells when grown at 10°C, and this phenotype too, disappered when rpoS was mutated in parallel indicating a RpoS-dependency. A csrA (sup) mutant was also growth attenuated a low temperature. An rpoS/csrA (sup) double mutant was also growth attenuated, indicating that the phenotype of the csrA mutant was independent from RpoS. CONCLUSIONS The cold sensitivity of clpP mutant was associated with increased levels of RpoS and probably caused by toxic levels of RpoS. Although a csrA mutant also accumulated high level of RpoS, growth impairment caused by lack of csrA was not related to RpoS levels in a similar way.
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Affiliation(s)
| | | | | | | | | | - John Elmerdahl Olsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, Frederiksberg C 1870, Denmark.
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Krisko A, Copic T, Gabaldón T, Lehner B, Supek F. Inferring gene function from evolutionary change in signatures of translation efficiency. Genome Biol 2014; 15:R44. [PMID: 24580753 PMCID: PMC4054840 DOI: 10.1186/gb-2014-15-3-r44] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 03/03/2014] [Indexed: 11/13/2022] Open
Abstract
Background The genetic code is redundant, meaning that most amino acids can be encoded by more than one codon. Highly expressed genes tend to use optimal codons to increase the accuracy and speed of translation. Thus, codon usage biases provide a signature of the relative expression levels of genes, which can, uniquely, be quantified across the domains of life. Results Here we describe a general statistical framework to exploit this phenomenon and to systematically associate genes with environments and phenotypic traits through changes in codon adaptation. By inferring evolutionary signatures of translation efficiency in 911 bacterial and archaeal genomes while controlling for confounding effects of phylogeny and inter-correlated phenotypes, we linked 187 gene families to 24 diverse phenotypic traits. A series of experiments in Escherichia coli revealed that 13 of 15, 19 of 23, and 3 of 6 gene families with changes in codon adaptation in aerotolerant, thermophilic, or halophilic microbes. Respectively, confer specific resistance to, respectively, hydrogen peroxide, heat, and high salinity. Further, we demonstrate experimentally that changes in codon optimality alone are sufficient to enhance stress resistance. Finally, we present evidence that multiple genes with altered codon optimality in aerobes confer oxidative stress resistance by controlling the levels of iron and NAD(P)H. Conclusions Taken together, these results provide experimental evidence for a widespread connection between changes in translation efficiency and phenotypic adaptation. As the number of sequenced genomes increases, this novel genomic context method for linking genes to phenotypes based on sequence alone will become increasingly useful.
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Alleron L, Khemiri A, Koubar M, Lacombe C, Coquet L, Cosette P, Jouenne T, Frere J. VBNC Legionella pneumophila cells are still able to produce virulence proteins. WATER RESEARCH 2013; 47:6606-17. [PMID: 24064547 DOI: 10.1016/j.watres.2013.08.032] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 07/24/2013] [Accepted: 08/27/2013] [Indexed: 05/22/2023]
Abstract
Legionella pneumophila is the agent responsible for legionellosis. Numerous bacteria, including L. pneumophila, can enter into a viable but not culturable (VBNC) state under unfavorable environmental conditions. In this state, cells are unable to form colonies on standard medium but are still alive. Here we show that VBNC L. pneumophila cells, obtained by monochloramine treatment, were still able to synthesize proteins, some of which are involved in virulence. Protein synthesis was measured using (35)S-labeling and the proteomes of VBNC and culturable cells then compared. This analysis allowed the identification of nine proteins that were accumulated in the VBNC state. Among them, four were involved in virulence, i.e., the macrophage infectivity potentiator protein, the hypothetical protein lpl2247, the ClpP protease proteolytic subunit and the 27 kDa outer membrane protein. Others, i.e., the enoyl reductase, the electron transfer flavoprotein (alpha and beta subunits), the 50S ribosomal proteins (L1 and L25) are involved in metabolic and energy production pathways. However, resuscitation experiments performed with Acanthamoeba castellanii failed, suggesting that the accumulation of virulence factors by VBNC cells is not sufficient to maintain their virulence.
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Affiliation(s)
- Laëtitia Alleron
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipe Microbiologie de l'Eau, B36, Université de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France
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16
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Regulation of host hemoglobin binding by the Staphylococcus aureus Clp proteolytic system. J Bacteriol 2013; 195:5041-50. [PMID: 23995637 DOI: 10.1128/jb.00505-13] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein turnover is a key process for bacterial survival mediated by intracellular proteases. Proteolytic degradation reduces the levels of unfolded and misfolded peptides that accumulate in the cell during stress conditions. Three intracellular proteases, ClpP, HslV, and FtsH, have been identified in the Gram-positive bacterium Staphylococcus aureus, a pathogen responsible for significant morbidity and mortality worldwide. Consistent with their crucial role in protein turnover, ClpP, HslV, and FtsH affect a number of cellular processes, including metabolism, stress responses, and virulence. The ClpP protease is believed to be the principal degradation machinery in S. aureus. This study sought to identify the effect of the Clp protease on the iron-regulated surface determinant (Isd) system, which extracts heme-iron from host hemoglobin during infection and is critical to S. aureus pathogenesis. Inactivation of components of the Clp protease alters abundance of several Isd proteins, including the hemoglobin receptor IsdB. Furthermore, the observed changes in IsdB abundance are the result of transcriptional regulation, since transcription of isdB is decreased by clpP or clpX inactivation. In contrast, inactivation of clpC enhances isdB transcription and protein abundance. Loss of clpP or clpX impairs host hemoglobin binding and utilization and results in severe virulence defects in a systemic mouse model of infection. These findings suggest that the Clp proteolytic system is important for regulating nutrient iron acquisition in S. aureus. The Clp protease and Isd complex are widely conserved in bacteria; therefore, these data reveal a novel Clp-dependent regulation pathway that may be present in other bacterial pathogens.
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Characterizing the mode of action of Brevibacillus laterosporus B4 for control of bacterial brown strip of rice caused by A. avenae subsp. avenae RS-1. World J Microbiol Biotechnol 2013; 30:469-78. [PMID: 23990042 DOI: 10.1007/s11274-013-1469-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 08/20/2013] [Indexed: 12/23/2022]
Abstract
Biological control efficacy of Brevibacillus laterosporus B4 associated with rice rhizosphere was assessed against bacterial brown stripe of rice caused by Acidovorex avenae subsp. avenae. A biochemical bactericide (chitosan) was used as positive control in this experiment. Result of in vitro analysis indicated that B. laterosporus B4 and its culture filtrates (70%; v/v) exhibited low inhibitory effects than chitosan (5 mg/ml). However, culture suspension of B. laterosporus B4 prepared in 1% saline solution presented significant ability to control bacterial brown stripe in vivo. Bacterization of rice seeds for 24 h yielded a greater response (71.9%) for controlling brown stripe in vivo than chitosan (56%). Studies on mechanisms revealed that B. laterosporus B4 suppressed the biofilm formation and severely disrupted cell membrane integrity of A. avenae subsp. avenae, causing the leakage of intracellular substances. In addition, the expression level of virulence-related genes in pathogen recovered from biocontrol-agent-treated plants showed that the genes responsible for biofilm formation, motility, niche adaptation, membrane functionality and virulence of A. avenae subsp. avenae were down-regulated by B. laterosporus B4 treatment. The biocontrol activity of B. laterosporus B4 was attributed to a substance with protein nature. This protein nature was shown by using ammonium sulfate precipitation and subsequent treatment with protease. The results obtained from this study showed the potential effectiveness of B. laterosporus B4 as biocontrol agent in control of bacterial brown stripe of rice.
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Campbell AG, Campbell JH, Schwientek P, Woyke T, Sczyrba A, Allman S, Beall CJ, Griffen A, Leys E, Podar M. Multiple single-cell genomes provide insight into functions of uncultured Deltaproteobacteria in the human oral cavity. PLoS One 2013; 8:e59361. [PMID: 23555659 PMCID: PMC3608642 DOI: 10.1371/journal.pone.0059361] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/13/2013] [Indexed: 01/10/2023] Open
Abstract
Despite a long history of investigation, many bacteria associated with the human oral cavity have yet to be cultured. Studies that correlate the presence or abundance of uncultured species with oral health or disease highlight the importance of these community members. Thus, we sequenced several single-cell genomic amplicons from Desulfobulbus and Desulfovibrio (class Deltaproteobacteria) to better understand their function within the human oral community and their association with periodontitis, as well as other systemic diseases. Genomic data from oral Desulfobulbus and Desulfovibrio species were compared to other available deltaproteobacterial genomes, including from a subset of host-associated species. While both groups share a large number of genes with other environmental Deltaproteobacteria genomes, they encode a wide array of unique genes that appear to function in survival in a host environment. Many of these genes are similar to virulence and host adaptation factors of known human pathogens, suggesting that the oral Deltaproteobacteria have the potential to play a role in the etiology of periodontal disease.
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Affiliation(s)
- Alisha G. Campbell
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - James H. Campbell
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - Patrick Schwientek
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Alexander Sczyrba
- DOE Joint Genome Institute, Walnut Creek, California, United States of America
| | - Steve Allman
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
| | - Clifford J. Beall
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Ann Griffen
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Eugene Leys
- College of Dentistry, Ohio State University, Columbus, Ohio, United States of America
| | - Mircea Podar
- Genome Science and Technology Program, University of Tennessee, Knoxville, Tennessee, United States of America
- Biosciences Division, Oak Ridge National Laboratories, Oak Ridge, Tennessee, United States of America
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
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Sun Y, Li X, Li W, Zhao M, Wang L, Liu S, Zeng J, Liu Z, Jia J. Proteomic analysis of the function of spot in Helicobacter pylori anti-oxidative stress in vitro and colonization in vivo. J Cell Biochem 2013; 113:3393-402. [PMID: 22678710 DOI: 10.1002/jcb.24215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
As a microaerobe, Helicobacter pylori employs the global regulator SpoT for defending against oxidative stress in vitro. However, the mechanisms how SpoT affects bacterial gene expression is still unknown. Moreover, the function of SpoT in H. pylori colonization in the host is remaining undetermined. To explore the functions of the SpoT in H. pylori pathogenesis, we constructed H. pylori 26695 spoT-deficient mutant (ΔspoT). While grown in ambient atmosphere, protein expression profile of the ΔspoT was analyzed with 2D gel electrophoresis and real-time PCR. Compared to the wild type, the spoT-deficient strain downregulated its transcription of the oxidative-induced genes, as well as the genes responsible for protein degradation and that related to energy metabolism. Meanwhile, the colonization ability of ΔspoT strains in Mongolian gerbil was tested, the results demonstrated a decayed colonization in the mouse stomach with ΔspoT than the wild type. As a matter of facts, the AGS cells infected with the ΔspoT strains excreted increased level of the gastric inflammation cytokines IL-8, and the ΔspoT strains showed poor survival ability when treated with reactive oxygen stress (sodium nitroprusside). The elevated capacity of stimulating cytokines and fragility to reactive oxygen stress may be contribute to decreased colonization of the spoT-deficient mutant in the mouse stomach. Conclusively, we speculate that spoT is a key regulator of the genes for H. pylori spreading in the air and colonization in host stomach.
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Affiliation(s)
- Yundong Sun
- Department of Microbiology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong, China
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20
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Xie F, Zhang Y, Li G, Zhou L, Liu S, Wang C. The ClpP protease is required for the stress tolerance and biofilm formation in Actinobacillus pleuropneumoniae. PLoS One 2013; 8:e53600. [PMID: 23326465 PMCID: PMC3543445 DOI: 10.1371/journal.pone.0053600] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Accepted: 11/30/2012] [Indexed: 01/12/2023] Open
Abstract
In the respiratory tract and lung tissue, a balanced physiological response is essential for Actinobacillus pleuropneumoniae to survive various types of challenges. ClpP, the catalytic core of the Clp proteolytic complex, is involved in various stresses response and regulation of biofilm formation in many pathogenic bacteria. To investigate the role of ClpP in the virulence of A. pleuropneumoniae, the clpP gene was deleted by homologous recombination, resulting in the mutant strain S8ΔclpP. The reduced growth of S8ΔclpP mutant at high temperatures and under several other stress conditions suggests that the ClpP protein is required for the stress tolerance of A. pleuropneumoniae. Interestingly, we observed that the S8ΔclpP mutant exhibited an increased ability to take up iron in vitro compared to the wild-type strain. We also found that the cells without ClpP displayed rough and irregular surfaces and increased cell volume relative to the wild-type strain using scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) revealed that the S8ΔclpP mutant showed decreased biofilm formation compared to the wild-type strain. We examined the transcriptional profiles of the wild type S8 and the S8ΔclpP mutant strains of A. pleuropneumoniae using RNA sequencing. Our analysis revealed that the expression of 16 genes was changed by the deletion of the clpP gene. The data presented in this study illustrate the important role of ClpP protease in the stress response, iron acquisition, cell morphology and biofilm formation related to A. pleuropneumoniae and further suggest a putative role of ClpP protease in virulence regulation.
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Affiliation(s)
- Fang Xie
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Yanhe Zhang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Gang Li
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Long Zhou
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Siguo Liu
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Chunlai Wang
- State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
- * E-mail:
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Feinbaum RL, Urbach JM, Liberati NT, Djonovic S, Adonizio A, Carvunis AR, Ausubel FM. Genome-wide identification of Pseudomonas aeruginosa virulence-related genes using a Caenorhabditis elegans infection model. PLoS Pathog 2012; 8:e1002813. [PMID: 22911607 PMCID: PMC3406104 DOI: 10.1371/journal.ppat.1002813] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 06/06/2012] [Indexed: 12/27/2022] Open
Abstract
Pseudomonas aeruginosa strain PA14 is an opportunistic human pathogen capable of infecting a wide range of organisms including the nematode Caenorhabditis elegans. We used a non-redundant transposon mutant library consisting of 5,850 clones corresponding to 75% of the total and approximately 80% of the non-essential PA14 ORFs to carry out a genome-wide screen for attenuation of PA14 virulence in C. elegans. We defined a functionally diverse 180 mutant set (representing 170 unique genes) necessary for normal levels of virulence that included both known and novel virulence factors. Seven previously uncharacterized virulence genes (ABC transporters PchH and PchI, aminopeptidase PepP, ATPase/molecular chaperone ClpA, cold shock domain protein PA0456, putative enoyl-CoA hydratase/isomerase PA0745, and putative transcriptional regulator PA14_27700) were characterized with respect to pigment production and motility and all but one of these mutants exhibited pleiotropic defects in addition to their avirulent phenotype. We examined the collection of genes required for normal levels of PA14 virulence with respect to occurrence in P. aeruginosa strain-specific genomic regions, location on putative and known genomic islands, and phylogenetic distribution across prokaryotes. Genes predominantly contributing to virulence in C. elegans showed neither a bias for strain-specific regions of the P. aeruginosa genome nor for putatively horizontally transferred genomic islands. Instead, within the collection of virulence-related PA14 genes, there was an overrepresentation of genes with a broad phylogenetic distribution that also occur with high frequency in many prokaryotic clades, suggesting that in aggregate the genes required for PA14 virulence in C. elegans are biased towards evolutionarily conserved genes.
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Affiliation(s)
- Rhonda L Feinbaum
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, United States of America.
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Borlace GN, Keep SJ, Prodoehl MJR, Jones HF, Butler RN, Brooks DA. A role for altered phagosome maturation in the long-term persistence of Helicobacter pylori infection. Am J Physiol Gastrointest Liver Physiol 2012; 303:G169-79. [PMID: 22575220 DOI: 10.1152/ajpgi.00320.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The vigorous host immune response that is mounted against Helicobacter pylori is unable to eliminate this pathogenic bacterium from its niche in the human gastric mucosa. This results in chronic inflammation, which can develop into gastric or duodenal ulcers in 10% of infected individuals and gastric cancer in 1% of infections. The determinants for these more severe pathologies include host (e.g., high IL-1β expression polymorphisms), bacterial [e.g., cytotoxicity-associated gene (cag) pathogenicity island], and environmental (e.g., dietary nitrites) factors. However, it is the failure of host immune effector cells to eliminate H. pylori that underlies its persistence and the subsequent H. pylori-associated disease. Here we discuss the mechanisms used by H. pylori to survive the host immune response and, in particular, the role played by altered phagosome maturation.
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Affiliation(s)
- Glenn N Borlace
- Mechanisms in Cell Biology and Disease Research Group, School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, Univ. of South Australia, South Australia 5001, Australia.
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The influence of ATP-dependent proteases on a variety of nucleoid-associated processes. J Struct Biol 2012; 179:181-92. [PMID: 22683345 DOI: 10.1016/j.jsb.2012.05.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 05/24/2012] [Accepted: 05/26/2012] [Indexed: 01/07/2023]
Abstract
ATP-dependent proteases are crucial components of all living cells and are involved in a variety of responses to physiological and environmental changes. Nucleoids are dynamic nucleoprotein complexes present in bacteria and eukaryotic organelles (mitochondria and plastids) and are the place where the majority of cellular responses to stress begin. These structures are actively remodeled in reaction to changing environmental and physiological conditions. The levels of nucleoid protein components (e.g. DNA-stabilizing proteins, transcription factors, replication proteins) therefore have to be continually regulated. ATP-dependent proteases have all the characteristics needed to fulfill this requirement. Some of them bind nucleic acids, but above all, they control and maintain the level of many DNA-binding proteins. In this review we will discuss the roles of the Lon, ClpAP, ClpXP, HslUV and FtsH proteases in the maintenance, stability, transcription and repair of DNA in eubacterial and mitochondrial nucleoids.
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Stent A, Every AL, Sutton P. Helicobacter pylori defense against oxidative attack. Am J Physiol Gastrointest Liver Physiol 2012; 302:G579-87. [PMID: 22194421 DOI: 10.1152/ajpgi.00495.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Helicobacter pylori is a microaerophilic, gram-negative pathogen of the human stomach. Despite the chronic active gastritis that develops following colonization, H. pylori is able to persist unharmed in the stomach for decades. Much of the damage caused by gastric inflammation results from the accumulation of reactive oxygen/nitrogen species within the stomach environment, which can induce oxidative damage in a wide range of biological molecules. Without appropriate defenses, this oxidative damage would be able to rapidly kill nearby H. pylori, but the organism employs a range of measures, including antioxidant enzymes, biological repair systems, and inhibitors of oxidant generation, to counter the attack. Despite the variety of measures employed to defend against oxidative injury, these processes are intimately interdependent, and any deficiency within the antioxidant system is generally sufficient to cause substantial impairment of H. pylori viability and persistence. This review provides an overview of the development of oxidative stress during H. pylori gastritis and examines the methods the organism uses to survive the resultant damage.
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Affiliation(s)
- Andrew Stent
- Centre for Animal Biotechnology, School of Veterinary Science, University of Melbourne, Parkville, Victoria, Australia
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25
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Benaroudj N, Raynal B, Miot M, Ortiz-Lombardia M. Assembly and proteolytic processing of mycobacterial ClpP1 and ClpP2. BMC BIOCHEMISTRY 2011; 12:61. [PMID: 22132756 PMCID: PMC3258218 DOI: 10.1186/1471-2091-12-61] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 12/01/2011] [Indexed: 01/13/2023]
Abstract
BACKGROUND Caseinolytic proteases (ClpPs) are barrel-shaped self-compartmentalized peptidases involved in eliminating damaged or short-lived regulatory proteins. The Mycobacterium tuberculosis (MTB) genome contains two genes coding for putative ClpPs, ClpP1 and ClpP2 respectively, that are likely to play a role in the virulence of the bacterium. RESULTS We report the first biochemical characterization of ClpP1 and ClpP2 peptidases from MTB. Both proteins were produced and purified in Escherichia coli. Use of fluorogenic model peptides of diverse specificities failed to show peptidase activity with recombinant mycobacterial ClpP1 or ClpP2. However, we found that ClpP1 had a proteolytic activity responsible for its own cleavage after the Arg8 residue and cleavage of ClpP2 after the Ala12 residue. In addition, we showed that the absence of any peptidase activity toward model peptides was not due to an obstruction of the entry pore by the N-terminal flexible extremity of the proteins, nor to an absolute requirement for the ClpX or ClpC ATPase complex. Finally, we also found that removing the putative propeptides of ClpP1 and ClpP2 did not result in cleavage of model peptides. We have also shown that recombinant ClpP1 and ClpP2 do not assemble in the conventional functional tetradecameric form but in lower order oligomeric species ranging from monomers to heptamers. The concomitant presence of both ClpP1 and ClpP2 did not result in tetradecameric assembly. Deleting the amino-terminal extremity of ClpP1 and ClpP2 (the putative propeptide or entry gate) promoted the assembly in higher order oligomeric species, suggesting that the flexible N-terminal extremity of mycobacterial ClpPs participated in the destabilization of interaction between heptamers. CONCLUSION Despite the conservation of a Ser protease catalytic triad in their primary sequences, mycobacterial ClpP1 and ClpP2 do not have conventional peptidase activity toward peptide models and display an unusual mechanism of self-assembly. Therefore, the mechanism underlying their peptidase and proteolytic activities might differ from that of other ClpP proteolytic complexes.
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Affiliation(s)
- Nadia Benaroudj
- Institut Pasteur, Unité de Biologie des Spirochètes, Institut Pasteur, F-75015 Paris, France.
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Vinckx T, Wei Q, Matthijs S, Noben JP, Daniels R, Cornelis P. A proteome analysis of the response of a Pseudomonas aeruginosa oxyR mutant to iron limitation. Biometals 2011; 24:523-32. [PMID: 21207115 DOI: 10.1007/s10534-010-9403-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/22/2010] [Indexed: 11/30/2022]
Abstract
In Pseudomonas aeruginosa the response to oxidative stress is orchestrated by the LysR regulator OxyR by activation of the transcription of two catalase genes (katA and katB), of the alkyl-hydroxyperoxidases ahpCF and ahpB. Next to the expected high sensitivity to oxidative stress generated by reactive oxygen species (ROS: H(2)O(2), O(2)(-)), the oxyR mutant shows a defective growth under conditions of iron limitation (Vinckx et al. 2008). Although production and uptake of the siderophore pyoverdine is not affected by the absence of oxyR, the mutant is unable to satisfy its need for iron when grown under iron limiting conditions. In order to get a better insight into the effects caused by iron limitation on the physiological response of the oxyR mutant we decided to compare the proteomes of the wild type and the mutant grown in the iron-poor casamino acids medium (CAA), in CAA plus H(2)O(2), and in CAA plus the strong iron chelator ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) (EDDHA). Especially in the presence of hydrogen peroxide the oxyR cells increase the production of stress proteins (Dps and IbpA). The superoxide dismutase SodM is produced in higher amounts in the oxyR mutant grown in CAA plus H(2)O(2). The PchB protein, a isochorismate-pyruvate lyase involved in the siderophore pyochelin biosynthesis is not detectable in the extracts from the oxyR mutant grown in the presence of hydrogen peroxide. When cells were grown in the presence of EDDHA, we observed a reduction of the ferric uptake regulator (Fur), and an increase in the two subunits of the succinyl-CoA synthetase and the fumarase FumC1.
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Affiliation(s)
- Tiffany Vinckx
- Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, VIB, Vrije Universiteit Brussel, Brussels, Belgium
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Use of a Dictyostelium model for isolation of genetic loci associated with phagocytosis and virulence in Klebsiella pneumoniae. Infect Immun 2010; 79:997-1006. [PMID: 21173313 DOI: 10.1128/iai.00906-10] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Phagocytosis resistance is an important virulence factor in Klebsiella pneumoniae. Dictyostelium has been used to study the interaction between phagocytes and bacteria because of its similarity to mammalian macrophages. In this study, we used a Dictyostelium model to investigate genes for resistance to phagocytosis in NTUH-K2044, a strain of K. pneumoniae causing pyogenic liver abscess that is highly resistant to phagocytosis. A total of 2,500 transposon mutants were screened by plaque assay, and 29 of them permitted phagocytosis by Dictyostelium. In the 29 mutants, six loci were identified; three were capsular synthesis genes. Of the other three, one was related to carnitine metabolism, one encoded a subunit of protease (clpX), and one encoded a lipopolysaccharide O-antigen transporter (wzm). Deletion and complementation of these genes showed that only ΔclpX and Δwzm mutants became susceptible to Dictyostelium phagocytosis, and their complementation restored the phagocytosis resistance phenotype. These two mutants were also susceptible to phagocytosis by human neutrophils and revealed attenuated virulence in a mouse model, implying that they play important roles in the pathogenesis of K. pneumoniae. Furthermore, we demonstrated that clpP, which exists in an operon with clpX, was also involved in resistance to phagocytosis. The transcriptional profile of ΔclpX was examined by microarray analysis and revealed a 3-fold lower level of expression of capsular synthesis genes. Therefore, we have identified genes involved in resistance to phagocytosis in K. pneumoniae using Dictyostelium, and this model is useful to explore genes associated with resistance to phagocytosis in heavily encapsulated bacteria.
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The ClpP protease homologue is required for the transmission traits and cell division of the pathogen Legionella pneumophila. BMC Microbiol 2010; 10:54. [PMID: 20167127 PMCID: PMC2838875 DOI: 10.1186/1471-2180-10-54] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 02/19/2010] [Indexed: 01/04/2023] Open
Abstract
Background Legionella pneumophila, the intracellular bacterial pathogen that causes Legionnaires' disease, exhibit characteristic transmission traits such as elevated stress tolerance, shortened length and virulence during the transition from the replication phase to the transmission phase. ClpP, the catalytic core of the Clp proteolytic complex, is widely involved in many cellular processes via the regulation of intracellular protein quality. Results In this study, we showed that ClpP was required for optimal growth of L. pneumophila at high temperatures and under several other stress conditions. We also observed that cells devoid of clpP exhibited cell elongation, incomplete cell division and compromised colony formation. Furthermore, we found that the clpP-deleted mutant was more resistant to sodium stress and failed to proliferate in the amoebae host Acanthamoeba castellanii. Conclusions The data present in this study illustrate that the ClpP protease homologue plays an important role in the expression of transmission traits and cell division of L. pneumophila, and further suggest a putative role of ClpP in virulence regulation.
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Ingmer H, Brøndsted L. Proteases in bacterial pathogenesis. Res Microbiol 2009; 160:704-10. [PMID: 19778606 DOI: 10.1016/j.resmic.2009.08.017] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/31/2009] [Accepted: 08/31/2009] [Indexed: 01/03/2023]
Abstract
Bacterial pathogens rely on proteolysis for protein quality control under adverse conditions experienced in the host, as well as for the timely degradation of central virulence regulators. We have focused on the contribution of the conserved Lon, Clp, HtrA and FtsH proteases to pathogenesis and have highlighted common biological processes for which their activities are important for virulence.
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Affiliation(s)
- Hanne Ingmer
- Department of Veterinary Disease Biology, University of Copenhagen, Faculty of Life Sciences Stigbøjlen 4, University of Copenhagen, Frederiksberg C. DK1870, Denmark.
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