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Fusarium graminearum Ste3 G-Protein Coupled Receptor: A Mediator of Hyphal Chemotropism and Pathogenesis. mSphere 2022; 7:e0045622. [PMID: 36377914 PMCID: PMC9769807 DOI: 10.1128/msphere.00456-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Previous studies on Fusarium species have highlighted the involvement of the Ste2 G-protein-coupled receptor (GPCR) in mediating polarized hyphal growth toward host-released peroxidase. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to Fusarium graminearum chemotropism and pathogenicity. Fgste3Δ deletion strains were found to be compromised in the chemotropic response toward peroxidase, development of lesions on germinating wheat, and infection of Arabidopsis thaliana leaves. In the absence of FgSte3 or FgSte2, F. graminearum cells exposed to peroxidase showed no phosphorylation of the cell-wall integrity, mitogen-activated protein kinase pathway component Mgv1. In addition, transcriptomic gene expression profiling yielded a list of genes involved in cellular reorganization, cell wall remodeling, and infection-mediated responses that were differentially modulated by peroxidase when FgSte3 was present. Deletion of FgSte3 yielded the downregulation of genes associated with mycotoxin biosynthesis and appressorium development, compared to the wild-type strain, both in the presence of peroxidase. Together, these findings contribute to our understanding of the mechanism underlying fungal chemotropism and pathogenesis while raising the novel hypothesis that FgSte2 and FgSte3 are interdependent on each other for the mediation of the redirection of hyphal growth in response to host-derived peroxidase. IMPORTANCE Fusarium head blight of wheat, caused by the filamentous fungus Fusarium graminearum, leads to devastating global food shortages and economic losses. Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to F. graminearum chemotropism and pathogenicity. These findings contribute to our understanding of the mechanisms underlying fungal chemotropism and pathogenesis.
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Luo XQ, Wang P, Li JL, Ahmad M, Duan L, Yin LZ, Deng QQ, Fang BZ, Li SH, Li WJ. Viral community-wide auxiliary metabolic genes differ by lifestyles, habitats, and hosts. MICROBIOME 2022; 10:190. [PMID: 36333738 PMCID: PMC9636769 DOI: 10.1186/s40168-022-01384-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/04/2022] [Indexed: 06/02/2023]
Abstract
BACKGROUND Viral-encoded auxiliary metabolic genes (AMGs) are important toolkits for modulating their hosts' metabolisms and the microbial-driven biogeochemical cycles. Although the functions of AMGs have been extensively reported in numerous environments, we still know little about the drivers that shape the viral community-wide AMG compositions in natural ecosystems. Exploring the drivers of viral community-wide AMG compositions is critical for a deeper understanding of the complex interplays among viruses, hosts, and the environments. RESULTS Here, we investigated the impact of viral lifestyles (i.e., lytic and lysogenic), habitats (i.e., water, particle, and sediment), and prokaryotic hosts on viral AMG profiles by utilizing metagenomic and metatranscriptomic techniques. We found that viral lifestyles were the most important drivers, followed by habitats and host identities. Specifically, irrespective of what habitats viruses came from, lytic viruses exhibited greater AMG diversity and tended to encode AMGs for chaperone biosynthesis, signaling proteins, and lipid metabolism, which could boost progeny reproduction, whereas temperate viruses were apt to encode AMGs for host survivability. Moreover, the lytic and temperate viral communities tended to mediate the microbial-driven biogeochemical cycles, especially nitrogen metabolism, in different manners via AMGs. When focusing on each lifestyle, we further found clear dissimilarity in AMG compositions between water and sediment, as well the divergent AMGs encoded by viruses infecting different host orders. CONCLUSIONS Overall, our study provides a first systematic characterization of the drivers of viral community-wide AMG compositions and further expands our knowledge of the distinct interactions of lytic and temperate viruses with their prokaryotic hosts from an AMG perspective, which is critical for understanding virus-host-environment interactions in natural conditions. Video Abstract.
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Affiliation(s)
- Xiao-Qing Luo
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Pandeng Wang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
- School of Ecology, Shenzhen Campus of Sun Yat-Sen University, Shenzhen, 518107, People's Republic of China.
| | - Jia-Ling Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Manzoor Ahmad
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Li Duan
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Ling-Zi Yin
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Qi-Qi Deng
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Bao-Zhu Fang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, People's Republic of China
| | - Shan-Hui Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, People's Republic of China.
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Leshchiner D, Rosconi F, Sundaresh B, Rudmann E, Ramirez LMN, Nishimoto AT, Wood SJ, Jana B, Buján N, Li K, Gao J, Frank M, Reeve SM, Lee RE, Rock CO, Rosch JW, van Opijnen T. A genome-wide atlas of antibiotic susceptibility targets and pathways to tolerance. Nat Commun 2022; 13:3165. [PMID: 35672367 PMCID: PMC9174251 DOI: 10.1038/s41467-022-30967-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/26/2022] [Indexed: 11/10/2022] Open
Abstract
Detailed knowledge on how bacteria evade antibiotics and eventually develop resistance could open avenues for novel therapeutics and diagnostics. It is thereby key to develop a comprehensive genome-wide understanding of how bacteria process antibiotic stress, and how modulation of the involved processes affects their ability to overcome said stress. Here we undertake a comprehensive genetic analysis of how the human pathogen Streptococcus pneumoniae responds to 20 antibiotics. We build a genome-wide atlas of drug susceptibility determinants and generated a genetic interaction network that connects cellular processes and genes of unknown function, which we show can be used as therapeutic targets. Pathway analysis reveals a genome-wide atlas of cellular processes that can make a bacterium less susceptible, and often tolerant, in an antibiotic specific manner. Importantly, modulation of these processes confers fitness benefits during active infections under antibiotic selection. Moreover, screening of sequenced clinical isolates demonstrates that mutations in genes that decrease antibiotic sensitivity and increase tolerance readily evolve and are frequently associated with resistant strains, indicating such mutations could be harbingers for the emergence of antibiotic resistance.
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Affiliation(s)
| | - Federico Rosconi
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA
| | | | - Emily Rudmann
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA
| | | | - Andrew T Nishimoto
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Stephen J Wood
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA
| | - Bimal Jana
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA
| | - Noemí Buján
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA
| | - Kaicheng Li
- Chemistry Department, Boston College, Chestnut Hill, MA, 02467, USA
| | - Jianmin Gao
- Chemistry Department, Boston College, Chestnut Hill, MA, 02467, USA
| | - Matthew Frank
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Stephanie M Reeve
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Tim van Opijnen
- Biology Department, Boston College, Chestnut Hill, MA, 02467, USA.
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DnaJ and ClpX are required for HitRS and HssRS two-component system signaling in Bacillus anthracis. Infect Immun 2021; 90:e0056021. [PMID: 34748369 DOI: 10.1128/iai.00560-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis is the causative agent of anthrax. This Gram-positive bacterium poses a substantial risk to human health due to high mortality rates and the potential for malicious use as a bioterror weapon. To survive within the vertebrate host, B. anthracis relies on two-component system (TCS) signaling to sense host-induced stresses and respond to alterations in the environment through changes in target gene expression. HitRS and HssRS are cross-regulating TCSs in B. anthracis that respond to cell envelope disruptions and high heme levels, respectively. In this study, an unbiased and targeted genetic selection was designed to identify gene products that are involved in HitRS and HssRS signaling. This selection led to the identification of inactivating mutations within dnaJ and clpX that disrupt HitRS- and HssRS-dependent gene expression. DnaJ and ClpX are the substrate-binding subunits of the DnaJK protein chaperone and ClpXP protease, respectively. DnaJ regulates the levels of HitR and HitS to facilitate signal transduction, while ClpX specifically regulates HitS levels. Together these results reveal that the protein homeostasis regulators, DnaJ and ClpX, function to maintain B. anthracis signal transduction activities through TCS regulation. One sentence summary: Use of a genetic selection strategy to identify modulators of two-component system signaling in Bacillus anthracis.
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Dong S, Chen H, Zhou Q, Liao N. Protein degradation control and regulation of bacterial survival and pathogenicity: the role of protein degradation systems in bacteria. Mol Biol Rep 2021; 48:7575-7585. [PMID: 34655017 DOI: 10.1007/s11033-021-06744-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/01/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Protein degradation systems play crucial roles in all the kingdoms of life. Their natural function is to eliminate proteins that are improperly synthesized, damaged, aggregated, or short-lived, ensuring the timely and accurate regulation of the response to abrupt environmental changes. Thus, proteolysis plays an important role in protein homeostasis, quality control, and the control of regulatory processes, such as adaptation and cell development. Except for the lysosome, ATPases Associated with various cellular Activities (AAA+) ATPase-protease complex is another major protein degradation system in the cell. METHODS AND RESULTS The AAA+ ATPase-protease complex is a giant energy-dependent protease complex found in almost all kinds of cells, including bacteria, archaea and eukarya. Based on sequence analysis of ClpQ (HslV) and 20S proteasome beta subunits, it was found that bacterial ClpQ possess multiple same highly conserved motifs with 20S proteasome beta subunits of archaea and eukaryote. In this review, we also discussed the structure and functional mechanism, protein degradation signals and pathogenic role of proteasome / Clp protease complex in prokaryotes. CONCLUSION Bacterial protein degradation systems play important roles in stress tolerance, protein quality control, DNA protection, transcription and pathogenicity of bacteria. But our current knowledge of the bacterial protease system is incomplete, and further research into the Clp protease complex and associated protein degradation signals will extend our understanding of the metabolism, physiology, reproduction, and pathogenicity of bacteria.
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Affiliation(s)
- Shilei Dong
- Department of Clinical Laboratory, Zhejiang Hospital, Hangzhou, 310013, China
| | - Honghu Chen
- Department of Microbiology, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, 310051, China
| | - Qingxue Zhou
- Department of Clinical Laboratory, Hangzhou Women's Hospital (Hangzhou Maternity and Child Health Care Hospital), Hangzhou, 310008, China
| | - Ningbo Liao
- College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang, 330045, China.
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Feng Y, Wang H, Lu HE, Yi L, Hong LI. Effects of ClpP protease on biofilm formation of Enterococcus faecalis. J Appl Oral Sci 2021; 29:e20200733. [PMID: 33656065 PMCID: PMC7934281 DOI: 10.1590/1678-7757-2020-0733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 11/25/2020] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES Enterococcus faecalis (E. faecalis), one of the main pathogens responsible for refractory periapical periodontitis and nosocomial infections, exhibits markedly higher pathogenicity in biofilms. Studies have shown that caseinolytic protease P (ClpP) is involved in biofilm formation. However, to date, few studies have investigated the role of ClpP in the survival of E. faecalis, and in enhancing biofilm formation. Therefore, we investigated the role of ClpP in the formation of E. faecalis biofilms. METHODOLOGY In our study, we used homologous recombination to construct clpP deleted and clpP complement strains of E. faecalis ATCC 29212. A viable colony counting method was used to analyze the growth patterns of E. faecalis. Crystal violet staining (CV) and confocal scanning laser microscopy (CLSM) were used to characterize biofilm mass formation and scanning electron microscopy (SEM) was used to observe the biofilm microstructure. Data was statistically analyzed via Student's t-test or one-way analysis of variance (ANOVA). RESULTS The results exhibited altered growth patterns for the clpP deletion strains and depleted polysaccharide matrix, resulting in reduced biofilm formation capacity compared to the standard strains. Moreover, ClpP was observed to increase biofilm formation in E. faecalis. CONCLUSION Our study shows that ClpP can increase biofilm formation in E. faecalis and emphasizes the importance of ClpP as a potential target against E. faecalis.
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Affiliation(s)
- Ying Feng
- Department of Endodontics, School of Stomatology, Capital Medical University
| | - Hongyuan Wang
- Department of Endodontics, School of Stomatology, Capital Medical University
| | - H E Lu
- Affiliated Stomatology Hospital of Guangzhou Medical University
| | - Liu Yi
- Laboratory of Tissue Regeneration and Immunology and Department of Periodontics, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, School of Stomatology, Capital Medical University
| | - L I Hong
- Department of Endodontics, School of Stomatology, Capital Medical University
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Wang Y, Wang Y, Liu B, Wang S, Li J, Gong S, Sun L, Yi L. pdh modulate virulence through reducing stress tolerance and biofilm formation of Streptococcus suis serotype 2. Virulence 2020; 10:588-599. [PMID: 31232165 PMCID: PMC6592368 DOI: 10.1080/21505594.2019.1631661] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Streptococcus suis serotype 2 (S. suis 2) is a zoonotic pathogen. It causes meningitis, arthritis, pneumonia and sepsis in pigs, leading to extremely high mortality, which seriously affects public health and the development of the pig industry. Pyruvate dehydrogenase (PDH) is an important sugar metabolism enzyme that is widely present in microorganisms, mammals and higher plants. It catalyzes the irreversible oxidative decarboxylation of pyruvate to acetyl-CoA and reduces NAD+ to NADH. In this study, we found that the virulence of the S. suis ZY05719 sequence type 7 pdh deletion strain (Δpdh) was significantly lower than the wild-type strain (WT) in the mouse infection model. The distribution of viable bacteria in the blood and organs of mice infected with the Δpdh was significantly lower than those infected with WT. Bacterial survival rates were reduced in response to temperature stress, salt stress and oxidative stress. Additionally, compared to WT, the ability to adhere to and invade PK15 cells, biofilm formation and stress resistance of Δpdh were significantly reduced. Moreover, real-time PCR results showed that pdh deletion reduced the expression of multiple adhesion-related genes. However, there was no significant difference in the correlation biological analysis between the complemented strain (CΔpdh) and WT. Moreover, the survival rate of Δpdh in RAW264.7 macrophages was significantly lower than that of the WT strain. This study shows that PDH is involved in the pathogenesis of S. suis 2 and reduction in virulence of Δpdh may be related to the decreased ability to resist stress of the strain.
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Affiliation(s)
- Yang Wang
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.,b Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang , Luoyang , China
| | - Yuxin Wang
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China
| | - Baobao Liu
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China
| | - Shaohui Wang
- c Shanghai Veterinary Research Institute , Chinese Academy of Agricultural Sciences , Shanghai , China
| | - Jinpeng Li
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China
| | - Shenglong Gong
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China
| | - Liyun Sun
- a College of Animal Science and Technology , Henan University of Science and Technology , Luoyang , China.,b Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang , Luoyang , China
| | - Li Yi
- d College of Life Science , Luoyang Normal University , Luoyang , China
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Electronic Cigarette (E-Cigarette) Vapor Exposure Alters the Streptococcus pneumoniae Transcriptome in a Nicotine-Dependent Manner without Affecting Pneumococcal Virulence. Appl Environ Microbiol 2020; 86:AEM.02125-19. [PMID: 31791951 DOI: 10.1128/aem.02125-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/12/2019] [Indexed: 12/25/2022] Open
Abstract
The effects of electronic cigarette (e-cigarette) vapor (EV) exposure on the physiology of respiratory microflora are not fully defined. We analyzed the effects of exposure to vapor from nicotine-containing and nicotine-free e-liquid formulations on the virulence and transcriptome of Streptococcus pneumoniae strain TIGR4, a pathogen that asymptomatically colonizes the human nasopharyngeal mucosa. TIGR4 was preexposed for 2 h to nicotine-containing EV extract (EVE+NIC), nicotine-free EV extract (EVE-NIC), cigarette smoke extract (CSE), or nutrient-rich tryptic soy (TS) broth (control). The differences between the treatment and control strains were explored using transcriptome sequencing (RNA sequencing [RNA-Seq]), in vitro virulence assays, and an in vivo mouse model of acute pneumonia. The analysis of RNA-Seq profiles revealed modest changes in the expression of 14 genes involved in sugar transport and metabolism in EVE-NIC-preexposed TIGR4 compared to the control, while EVE+NIC or CSE exposure altered expression of 264 and 982 genes, respectively, most of which were involved in metabolism and stress response. Infection in a mouse model of acute pneumonia with control TIGR4 or with TIGR4 preexposed to EVE+NIC, EVE-NIC, or CSE did not show significant differences in disease parameters, such as bacterial organ burden and respiratory cytokine response. Interestingly, TIGR4 exposed to CSE or EVE+NIC (but not EVE-NIC) exhibited moderate induction of biofilm formation. However, none of the treatment groups showed significant alterations in pneumococcal hydrophobicity or epithelial cell adherence. In summary, our study reports that exposure to EV significantly alters the S. pneumoniae transcriptome in a nicotine-dependent manner without affecting pneumococcal virulence.IMPORTANCE With the increasing popularity of e-cigarettes among cigarette smoking and nonsmoking adults and children and the recent reports of vaping-related lung illness and deaths, further analysis of the adverse health effects of e-cigarette vapor (EV) exposure is warranted. Since pathogenic bacteria such as Streptococcus pneumoniae can colonize the human nasopharynx as commensals, they may be affected by exposure to bioactive chemicals in EV. Hence, in this study we examined the effects of EV exposure on the physiology of S. pneumoniae strain TIGR4. In order to differentiate between the effects of nicotine and nonnicotine components, we specifically compared the RNA-Seq profiles and virulence of TIGR4 exposed to vapor from nicotine-containing and nicotine-free e-liquid formulations. We observed that nicotine-containing EV augmented TIGR4 biofilms and altered expression of TIGR4 genes predominantly involved in metabolism and stress response. However, neither nicotine-containing nor nicotine-free EV affected TIGR4 virulence in a mouse model.
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Roy S, Zhu Y, Ma J, Roy AC, Zhang Y, Zhong X, Pan Z, Yao H. Role of ClpX and ClpP in Streptococcus suis serotype 2 stress tolerance and virulence. Microbiol Res 2019; 223-225:99-109. [PMID: 31178057 DOI: 10.1016/j.micres.2019.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/19/2019] [Accepted: 04/11/2019] [Indexed: 10/27/2022]
Abstract
Streptococcus suis has received increasing attention for its involvement in severe infections in pigs and humans; however, their pathogenesis remains unclear. ClpX and ClpP, two subunits of the ATP-dependent caseinolytic protease Clp, play key roles in bacterial adaptation to various environmental stresses. In this study, a virulent S. suis serotype 2 strain, ZY05719, was employed to construct clpX and clpP deletion mutants (ΔclpX and ΔclpP, respectively) and their complementation strains. Both ΔclpX and ΔclpP displayed significantly reduced adaptability compared with the wild-type strain, evident through several altered phenotypes: formation of long cell chains, tendency to aggregate in culture, and reduced growth under acidic pH and H2O2-induced oxidative stress. ClpP and ClpX were required for the optimal growth during heat and cold stress, respectively. An in vitro experiment on RAW264.7 macrophage cells showed significantly increased sensitivity of ΔclpX and ΔclpP to phagocytosis compared with the wild-type strain. Mouse infection assays verified the deletion of clpX and clpP led to not only fewer clinical symptoms and lower mortality but also to a marked attenuation in bacterial colonization. These virulence-related phenotypes were restored by genetic complementation. Furthermore, the deletion of clpX or clpP caused a significant decrease in the expression of sodA, tpx, and apuA compared with the wild-type strain, suggesting that these genes may be regulated by ClpX and ClpP as downstream response factors to facilitate the bacterial tolerance against various environmental stresses. Taken together, these results suggest that ClpX and ClpP play important roles in stress tolerance for achieving the full virulence of S. suis serotype 2 during infection.
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Affiliation(s)
- Shipra Roy
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Yinchu Zhu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Jiale Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Animesh Chandra Roy
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yue Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Xiaojun Zhong
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Zihao Pan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China.
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Sitkiewicz I. How to become a killer, or is it all accidental? Virulence strategies in oral streptococci. Mol Oral Microbiol 2017; 33:1-12. [PMID: 28727895 DOI: 10.1111/omi.12192] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 01/03/2023]
Abstract
Streptococci are a diverse group of Gram-positive microorganisms sharing common virulence traits and similar strategies to escape the oral niche and establish an infection in other parts of the host organism. Invasive infection with oral streptococci is "a perfect storm" that requires the concerted action of multiple biotic and abiotic factors. Our understanding of streptococcal pathogenicity and infectivity should probably be less mechanistic and driven not only by the identification of novel virulence factors. The observed diversity of the genus, including the range of virulence and pathogenicity mechanisms, is most likely the result of interspecies interactions, a massive horizontal gene transfer between streptococci within a shared oral niche, recombination events, selection of specialized clones, and modification of regulatory circuits. Selective pressure by the host and bacterial communities is a driving force for the selection of virulence traits and shaping the streptococcal genome. Global regulatory events driving niche adaptation and interactions with bacterial communities and the host steer research interests towards attempts to define the oral interactome on the transcriptional level and define signal cross-feeding and co-expression and co-regulation of virulence genes.
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Affiliation(s)
- I Sitkiewicz
- Department of Molecular Microbiology, National Medicines Institute, Warsaw, Poland
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Turner AG, Ong CLY, Walker MJ, Djoko KY, McEwan AG. Transition Metal Homeostasis in Streptococcus pyogenes and Streptococcus pneumoniae. Adv Microb Physiol 2017; 70:123-191. [PMID: 28528647 DOI: 10.1016/bs.ampbs.2017.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Trace metals such as Fe, Mn, Zn and Cu are essential for various biological functions including proper innate immune function. The host immune system has complicated and coordinated mechanisms in place to either starve and/or overload invading pathogens with various metals to combat the infection. Here, we discuss the roles of Fe, Mn and Zn in terms of nutritional immunity, and also the roles of Cu and Zn in metal overload in relation to the physiology and pathogenesis of two human streptococcal species, Streptococcus pneumoniae and Streptococcus pyogenes. S. pneumoniae is a major human pathogen that is carried asymptomatically in the nasopharynx by up to 70% of the population; however, transition to internal sites can cause a range of diseases such as pneumonia, otitis media, meningitis and bacteraemia. S. pyogenes is a human pathogen responsible for diseases ranging from pharyngitis and impetigo, to severe invasive infections. Both species have overlapping capacity with respect to metal acquisition, export and regulation and how metal homeostasis relates to their virulence and ability to invade and survive within the host. It is becoming more apparent that metals have an important role to play in the control of infection, and with further investigations, it could lead to the potential use of metals in novel antimicrobial therapies.
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Affiliation(s)
- Andrew G Turner
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Cheryl-Lynn Y Ong
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Mark J Walker
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Karrera Y Djoko
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Alastair G McEwan
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
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12
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Zhao BB, Li XH, Zeng YL, Lu YJ. ClpP-deletion impairs the virulence of Legionella pneumophila and the optimal translocation of effector proteins. BMC Microbiol 2016; 16:174. [PMID: 27484084 PMCID: PMC4969725 DOI: 10.1186/s12866-016-0790-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/27/2016] [Indexed: 12/19/2022] Open
Abstract
Background The opportunistic bacterial pathogen Legionella pneumophila uses substrate effectors of Dot/Icm type IVB secretion system (T4BSS) to accomplish survival and replication in amoebae cells and mammalian alveolar macrophages. During the conversion between its highly resistant, infectious dormant form and vigorously growing, uninfectious replicative form, L. pneumophila utilizes a complicated regulatory network in which proteolysis may play a significant role. As a highly conserved core protease, ClpP is involved in various cellular processes as well as virulence in bacteria, and has been proved to be required for the expression of transmission traits and cell division of L. pneumophila. Results The clpP-deficient L. pneumophila strain failed to replicate and was digested in the first 3 h post-infection in mammalian cells J774A.1. Further investigation demonstrates that the clpP deficient mutant strain was unable to escape the endosome-lysosomal pathway in host cells. We also found that the clpP deficient mutant strain still expresses T4BSS components, induces contact-dependent cytotoxicity and translocate effector proteins RalF and LegK2, indicating that its T4BSS was overall functional. Interestingly, we further found that the translocation of several effector proteins is significantly reduced without ClpP. Conclusions The data indicate that ClpP plays an important role in regulating the virulence and effector translocation of Legionella pneumophila. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0790-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bei-Bei Zhao
- School of Life Sciences and Biomedical Center, Sun Yat-sen University, No. 135 Xingang road west, Guangzhou, 510275, China
| | - Xiang-Hui Li
- School of Life Sciences and Biomedical Center, Sun Yat-sen University, No. 135 Xingang road west, Guangzhou, 510275, China.,Present address: Jiangsu Information Institute of Science and Technology, Nanjing, 210042, China
| | - Yong-Lun Zeng
- School of Life Sciences and Biomedical Center, Sun Yat-sen University, No. 135 Xingang road west, Guangzhou, 510275, China.,Present address: School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Hong Kong, 999077, China
| | - Yong-Jun Lu
- School of Life Sciences and Biomedical Center, Sun Yat-sen University, No. 135 Xingang road west, Guangzhou, 510275, China.
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13
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Abstract
Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.
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14
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Cassenego APV, de Oliveira NEM, Laport MS, Abranches J, Lemos JA, Giambiagi-deMarval M. The CtsR regulator controls the expression of clpC, clpE and clpP and is required for the virulence of Enterococcus faecalis in an invertebrate model. Antonie van Leeuwenhoek 2016; 109:1253-9. [DOI: 10.1007/s10482-016-0727-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/28/2016] [Indexed: 10/21/2022]
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15
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Nguyen CT, Park SS, Rhee DK. Stress responses in Streptococcus species and their effects on the host. J Microbiol 2015; 53:741-9. [PMID: 26502957 DOI: 10.1007/s12275-015-5432-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 12/15/2022]
Abstract
Streptococci cause a variety of diseases, such as dental caries, pharyngitis, meningitis, pneumonia, bacteremia, endocarditis, erysipelas, and necrotizing fasciitis. The natural niche of this genus of bacteria ranges from the mouth and nasopharynx to the skin, indicating that the bacteria will inevitably be subjected to environmental changes during invasion into the host, where it is exposed to the host immune system. Thus, the Streptococcus-host interaction determines whether bacteria are cleared by the host's defenses or whether they survive after invasion to cause serious diseases. If this interaction was to be deciphered, it could aid in the development of novel preventive and therapeutic agents. Streptococcus species possess many virulent factors, such as peroxidases and heat-shock proteins (HSPs), which play key roles in protecting the bacteria from hostile host environments. This review will discuss insights into the mechanism(s) by which streptococci adapt to host environments. Additionally, we will address how streptococcal infections trigger host stress responses; however, the mechanism by which bacterial components modulate host stress responses remains largely unknown.
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Affiliation(s)
- Cuong Thach Nguyen
- School of Pharmacy, Sungkyunkwan University, Su-Won, 16419, Republic of Korea
| | - Sang-Sang Park
- School of Pharmacy, Sungkyunkwan University, Su-Won, 16419, Republic of Korea
| | - Dong-Kwon Rhee
- School of Pharmacy, Sungkyunkwan University, Su-Won, 16419, Republic of Korea.
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16
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Zhang JQ, Hou XH, Song XY, Ma XB, Zhao YX, Zhang SY. ClpP Affects Biofilm Formation of Streptococcus mutans Differently in the Presence of Cariogenic Carbohydrates Through Regulating gtfBC and ftf. Curr Microbiol 2015; 70:716-23. [DOI: 10.1007/s00284-015-0779-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 12/19/2014] [Indexed: 12/24/2022]
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17
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Brötz-Oesterhelt H, Sass P. Bacterial caseinolytic proteases as novel targets for antibacterial treatment. Int J Med Microbiol 2013; 304:23-30. [PMID: 24119566 DOI: 10.1016/j.ijmm.2013.09.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bacterial Clp proteases are important for protein turnover and homeostasis in order to maintain vital cellular functions particularly under stress conditions. Apart from their crucial role in general protein quality control by degrading abnormally folded or otherwise aberrant or malfunctioning proteins, their temporally and spatially precise proteolysis of key regulatory proteins additionally guides several developmental processes like cell motility, genetic competence, cell differentiation, sporulation as well as important aspects of virulence. Due to their apparent relevance for many physiological processes and their conservation among diverse bacterial species including human pathogens, Clp proteases have attracted considerable attention as targets for antibacterial action in recent years. Particularly a novel class of potent acyldepsipeptide antibiotics unleashes ClpP, the uniform proteolytic core unit of the degradative Clp complexes, to bring about bacterial death via uncontrolled proteolysis of proteins that are essential for bacterial viability. In addition, covalent inhibition of the catalytic center of ClpP by another class of small molecule inhibitors is investigated in the context of virulence inhibition. Both antibacterial mechanisms constitute innovative approaches with the potential to control infections caused by multi-resistant bacterial pathogens due to the lack of cross-resistance to established antibiotic classes.
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Affiliation(s)
- Heike Brötz-Oesterhelt
- Institute for Pharmaceutical Biology and Biotechnology, University of Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
| | - Peter Sass
- Institute for Pharmaceutical Biology and Biotechnology, University of Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany
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18
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Yesilkaya H, Andisi VF, Andrew PW, Bijlsma JJE. Streptococcus pneumoniae and reactive oxygen species: an unusual approach to living with radicals. Trends Microbiol 2013; 21:187-95. [PMID: 23415028 DOI: 10.1016/j.tim.2013.01.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/15/2013] [Accepted: 01/18/2013] [Indexed: 11/25/2022]
Abstract
Streptococcus pneumoniae, an aerotolerant anaerobe, is an important human pathogen that regularly encounters toxic oxygen radicals from the atmosphere and from the host metabolism and immune system. Additionally, S. pneumoniae produces large amounts of H2O2 as a byproduct of its metabolism, which contributes to its virulence but also has adverse effects on its biology. Understanding how S. pneumoniae defends against oxidative stress is far from complete, but it is apparent that it does not follow the current paradigm of having canonical enzymes to detoxify oxygen radicals or homologues of typical oxidative stress responsive global regulators. We will give an overview of how S. pneumoniae copes with oxygen radicals. Furthermore, we draw parallels with other pathogenic streptococcal species and provide future research perspectives.
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Affiliation(s)
- Hasan Yesilkaya
- University of Leicester, Department of Infection, Immunity, and Inflammation, Maurice Shock Building, University Road, P.O. Box 138, Leicester, LE1 9HN, UK
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19
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Cao J, Gong Y, Dong S, Zhang L, Lai X, Zhang X, Yin Y. Pneumococcal ClpP modulates the maturation and activation of human dendritic cells: implications for pneumococcal infections. J Leukoc Biol 2013; 93:737-49. [PMID: 23381472 DOI: 10.1189/jlb.0812428] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
DCs are essential for host immune response to pathogens. Pneumococcal diseases still remain to be a major global-health issue, and HSP100/ClpP is a ubiquitously present virulence determinant for Streptococcus pneumoniae. Here, we show that ClpP expression facilitates the uptake and phagocytosis of pneumococci by human DCs, and it could increase apoptosis of DCs infected with pneumococci. Furthermore, pneumococcal ClpP is required for optimal production of inflammatory cytokines and chemokines and an efficient activation of adaptive immune response in DCs. Complementary, purified rClpP protein recognizes TLR4 and functionally activates human DCs by augmenting the expression of surface molecules and the production of inflammatory cytokines and chemokines dependent on MAPKs and NF-κB signaling pathways. Besides, ClpP-treated DCs induce T cell proliferation and contribute to Th1 immune response. This study describes a novel role of ClpP in the interaction of DCs with pneumococci that could provide new insight for the progression of pneumococcal diseases and has important implications for designing pneumococcal protein vaccines.
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Affiliation(s)
- Ju Cao
- Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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20
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Abstract
Bacterial pathogens rely on proteolysis for variety of purposes during the infection process. In the cytosol, the main proteolytic players are the conserved Clp and Lon proteases that directly contribute to virulence through the timely degradation of virulence regulators and indirectly by providing tolerance to adverse conditions such as those experienced in the host. In the membrane, HtrA performs similar functions whereas the extracellular proteases, in close contact with host components, pave the way for spreading infections by degrading host matrix components or interfering with host cell signalling to short-circuit host cell processes. Common to both intra- and extracellular proteases is the tight control of their proteolytic activities. In general, substrate recognition by the intracellular proteases is highly selective which is, in part, attributed to the chaperone activity associated with the proteases either encoded within the same polypeptide or on separate subunits. In contrast, substrate recognition by extracellular proteases is less selective and therefore these enzymes are generally expressed as zymogens to prevent premature proteolytic activity that would be detrimental to the cell. These extracellular proteases are activated in complex cascades involving auto-processing and proteolytic maturation. Thus, proteolysis has been adopted by bacterial pathogens at multiple levels to ensure the success of the pathogen in contact with the human host.
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Affiliation(s)
- Dorte Frees
- Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Stigbøjlen 4, Frederiksberg, C 1870, Denmark
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21
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Fröhlich A, Gaupels F, Sarioglu H, Holzmeister C, Spannagl M, Durner J, Lindermayr C. Looking deep inside: detection of low-abundance proteins in leaf extracts of Arabidopsis and phloem exudates of pumpkin. PLANT PHYSIOLOGY 2012; 159:902-14. [PMID: 22555880 PMCID: PMC3387715 DOI: 10.1104/pp.112.198077] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/24/2012] [Indexed: 05/20/2023]
Abstract
The field of proteomics suffers from the immense complexity of even small proteomes and the enormous dynamic range of protein concentrations within a given sample. Most protein samples contain a few major proteins, which hamper in-depth proteomic analysis. In the human field, combinatorial hexapeptide ligand libraries (CPLL; such as ProteoMiner) have been used for reduction of the dynamic range of protein concentrations; however, this technique is not established in plant research. In this work, we present the application of CPLL to Arabidopsis (Arabidopsis thaliana) leaf proteins. One- and two-dimensional gel electrophoresis showed a decrease in high-abundance proteins and an enrichment of less abundant proteins in CPLL-treated samples. After optimization of the CPLL protocol, mass spectrometric analyses of leaf extracts led to the identification of 1,192 proteins in control samples and an additional 512 proteins after the application of CPLL. Upon leaf infection with virulent Pseudomonas syringae DC3000, CPLL beads were also used for investigating the bacterial infectome. In total, 312 bacterial proteins could be identified in infected Arabidopsis leaves. Furthermore, phloem exudates of pumpkin (Cucurbita maxima) were analyzed. CPLL prefractionation caused depletion of the major phloem proteins 1 and 2 and improved phloem proteomics, because 67 of 320 identified proteins were detectable only after CPLL treatment. In sum, our results demonstrate that CPLL beads are a time- and cost-effective tool for reducing major proteins, which often interfere with downstream analyses. The concomitant enrichment of less abundant proteins may facilitate a deeper insight into the plant proteome.
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Affiliation(s)
| | | | - Hakan Sarioglu
- Institute of Biochemical Plant Pathology (A.F., F.G., C.H., J.D., C.L.), Department of Protein Science (H.S.), and Institute of Bioinformatics and Systems Biology (M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, D–85764 Neuherberg, Germany
| | - Christian Holzmeister
- Institute of Biochemical Plant Pathology (A.F., F.G., C.H., J.D., C.L.), Department of Protein Science (H.S.), and Institute of Bioinformatics and Systems Biology (M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, D–85764 Neuherberg, Germany
| | - Manuel Spannagl
- Institute of Biochemical Plant Pathology (A.F., F.G., C.H., J.D., C.L.), Department of Protein Science (H.S.), and Institute of Bioinformatics and Systems Biology (M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, D–85764 Neuherberg, Germany
| | - Jörg Durner
- Institute of Biochemical Plant Pathology (A.F., F.G., C.H., J.D., C.L.), Department of Protein Science (H.S.), and Institute of Bioinformatics and Systems Biology (M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, D–85764 Neuherberg, Germany
| | - Christian Lindermayr
- Institute of Biochemical Plant Pathology (A.F., F.G., C.H., J.D., C.L.), Department of Protein Science (H.S.), and Institute of Bioinformatics and Systems Biology (M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, D–85764 Neuherberg, Germany
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22
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Wang H, Shen X, Zhao Y, Wang M, Zhong Q, Chen T, Hu F, Li M. Identification and proteome analysis of the two-component VirR/VirS system in epidemic Streptococcus suis serotype 2. FEMS Microbiol Lett 2012; 333:160-8. [DOI: 10.1111/j.1574-6968.2012.02611.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 05/21/2012] [Accepted: 05/25/2012] [Indexed: 11/29/2022] Open
Affiliation(s)
- Haihui Wang
- Department of Endocrinology, Southwest Hospital; Third Military Medical University; Chongqing; China
| | - Xiaodong Shen
- Department of Biochemistry and Molecular Biology; Third Military Medical University; Chongqing; China
| | - Yan Zhao
- Department of Microbiology; Third Military Medical University; Chongqing; China
| | - Min Wang
- Department of Microbiology; Third Military Medical University; Chongqing; China
| | - Qiu Zhong
- Department of Microbiology; Third Military Medical University; Chongqing; China
| | - Tian Chen
- Department of Microbiology; Third Military Medical University; Chongqing; China
| | - Fuquan Hu
- Department of Microbiology; Third Military Medical University; Chongqing; China
| | - Ming Li
- Department of Microbiology; Third Military Medical University; Chongqing; China
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23
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Kajfasz JK, Abranches J, Lemos JA. Transcriptome analysis reveals that ClpXP proteolysis controls key virulence properties of Streptococcus mutans. MICROBIOLOGY-SGM 2011; 157:2880-2890. [PMID: 21816882 DOI: 10.1099/mic.0.052407-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ClpXP proteolytic complex is critical for maintaining cellular homeostasis, as well as expression of virulence properties. However, with the exception of the Spx global regulator, the molecular mechanisms by which the ClpXP complex exerts its influence in Streptococcus mutans are not well understood. Here, microarray analysis was used to provide novel insights into the scope of ClpXP proteolysis in S. mutans. In a ΔclpP strain, 288 genes showed significant changes in relative transcript amounts (P≤0.001, twofold cut-off) as compared with the parent. Similarly, 242 genes were differentially expressed by a ΔclpX strain, 113 (47 %) of which also appeared in the ΔclpP microarrays. Several genes associated with cell growth were downregulated in both mutants, consistent with the slow-growth phenotype of the Δclp strains. Among the upregulated genes were those encoding enzymes required for the biosynthesis of intracellular polysaccharides (glg genes) and malolactic fermentation (mle genes). Enhanced expression of glg and mle genes in ΔclpP and ΔclpX strains correlated with increased storage of intracellular polysaccharide and enhanced malolactic fermentation activity, respectively. Expression of several genes known or predicted to be involved in competence and mutacin production was downregulated in the Δclp strains. Follow-up transformation efficiency and deferred antagonism assays validated the microarray data by showing that competence and mutacin production were dramatically impaired in the Δclp strains. Collectively, our results reveal the broad scope of ClpXP regulation in S. mutans homeostasis and identify several virulence-related traits that are influenced by ClpXP proteolysis.
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Affiliation(s)
- Jessica K Kajfasz
- Center for Oral Biology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Jacqueline Abranches
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.,Center for Oral Biology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - José A Lemos
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.,Center for Oral Biology, University of Rochester Medical Center, Rochester, NY 14642, USA
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24
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Zheng X, Zheng H, Lan R, Ye C, Wang Y, Zhang J, Jing H, Chen C, Segura M, Gottschalk M, Xu J. Identification of genes and genomic islands correlated with high pathogenicity in Streptococcus suis using whole genome tiling microarrays. PLoS One 2011; 6:e17987. [PMID: 21479213 PMCID: PMC3068143 DOI: 10.1371/journal.pone.0017987] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Accepted: 02/17/2011] [Indexed: 01/21/2023] Open
Abstract
Streptococcus suis is an important zoonotic pathogen that can cause meningitis and sepsis in both pigs and humans. Infections in humans have been sporadic worldwide but two severe outbreaks occurred in China in recent years, while infections in pigs are a major problem in the swine industry. Some S. suis strains are more pathogenic than others with 2 sequence types (ST), ST1 and ST7, being well recognized as highly pathogenic. We analyzed 31 isolates from 23 serotypes and 25 STs by NimbleGen tiling microarray using the genome of a high pathogenicity (HP) ST1 strain, GZ1, as reference and a new algorithm to detect gene content difference. The number of genes absent in a strain ranged from 49 to 225 with a total of 632 genes absent in at least one strain, while 1346 genes were found to be invariably present in all strains as the core genome of S. suis, accounting for 68% of the GZ1 genome. The majority of genes are located in chromosomal blocks with two or more contiguous genes. Sixty two blocks are absent in two or more strains and defined as regions of difference (RDs), among which 26 are putative genomic islands (GIs). Clustering and statistical analyses revealed that 8 RDs including 6 putative GIs and 21 genes within these RDs are significantly associated with HP. Three RDs encode known virulence related factors including the extracellular factor, the capsular polysaccharide and a SrtF pilus. The strains were divided into 5 groups based on population genetic analysis of multilocus sequence typing data and the distribution of the RDs among the groups revealed gain and loss of RDs in different groups. Our study elucidated the gene content diversity of S. suis and identified genes that potentially promote HP.
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Affiliation(s)
- Xiao Zheng
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Han Zheng
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Ruiting Lan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Changyun Ye
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Yiting Wang
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Ji Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Huaiqi Jing
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Chen Chen
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
| | - Mariela Segura
- Faculty of Veterinary Medicine, University of Montréal, St-Hyacinthe, Québec, Canada
| | - Marcelo Gottschalk
- Faculty of Veterinary Medicine, University of Montréal, St-Hyacinthe, Québec, Canada
| | - Jianguo Xu
- State Key Laboratory for Infectious Disease Prevention and Control, Changping, Beijing, China
- National Institute for Communicable Disease Control and Prevention, Changping, Beijing, China
- * E-mail:
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25
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Estorninho M, Smith H, Thole J, Harders-Westerveen J, Kierzek A, Butler RE, Neyrolles O, Stewart GR. ClgR regulation of chaperone and protease systems is essential for Mycobacterium tuberculosis parasitism of the macrophage. Microbiology (Reading) 2010; 156:3445-3455. [DOI: 10.1099/mic.0.042275-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chaperone and protease systems play essential roles in cellular homeostasis and have vital functions in controlling the abundance of specific cellular proteins involved in processes such as transcription, replication, metabolism and virulence. Bacteria have evolved accurate regulatory systems to control the expression and function of chaperones and potentially destructive proteases. Here, we have used a combination of transcriptomics, proteomics and targeted mutagenesis to reveal that the clp gene regulator (ClgR) of Mycobacterium tuberculosis activates the transcription of at least ten genes, including four that encode protease systems (ClpP1/C, ClpP2/C, PtrB and HtrA-like protease Rv1043c) and three that encode chaperones (Acr2, ClpB and the chaperonin Rv3269). Thus, M. tuberculosis ClgR controls a larger network of protein homeostatic and regulatory systems than ClgR in any other bacterium studied to date. We demonstrate that ClgR-regulated transcriptional activation of these systems is essential for M. tuberculosis to replicate in macrophages. Furthermore, we observe that this defect is manifest early in infection, as M. tuberculosis lacking ClgR is deficient in the ability to control phagosome pH 1 h post-phagocytosis.
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Affiliation(s)
- Megan Estorninho
- Division of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Hilde Smith
- Central Veterinary Institute of Wageningen UR, Division of Infectious Diseases, Animal Sciences Group, Edelhertweg 15, 8219 PH Lelystad, The Netherlands
| | - Jelle Thole
- Central Veterinary Institute of Wageningen UR, Division of Infectious Diseases, Animal Sciences Group, Edelhertweg 15, 8219 PH Lelystad, The Netherlands
| | - Jose Harders-Westerveen
- Central Veterinary Institute of Wageningen UR, Division of Infectious Diseases, Animal Sciences Group, Edelhertweg 15, 8219 PH Lelystad, The Netherlands
| | - Andrzej Kierzek
- Division of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Rachel E. Butler
- Division of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique and Université Paul Sabatier (UMR 5089), 205 Route de Narbonne, 31000 Toulouse, France
| | - Graham R. Stewart
- Division of Microbial Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
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26
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Hanin A, Sava I, Bao Y, Huebner J, Hartke A, Auffray Y, Sauvageot N. Screening of in vivo activated genes in Enterococcus faecalis during insect and mouse infections and growth in urine. PLoS One 2010; 5:e11879. [PMID: 20686694 PMCID: PMC2912369 DOI: 10.1371/journal.pone.0011879] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 07/05/2010] [Indexed: 12/15/2022] Open
Abstract
Enterococcus faecalis is part of the commensal microbiota of humans and its main habitat is the gastrointestinal tract. Although harmless in healthy individuals, E. faecalis has emerged as a major cause of nosocomial infections. In order to better understand the transformation of a harmless commensal into a life-threatening pathogen, we developed a Recombination-based In VivoExpression Technology for E. faecalis. Two R-IVET systems with different levels of sensitivity have been constructed in a E. faecalis V583 derivative strain and tested in the insect model Galleria mellonella, during growth in urine, in a mouse bacteremia and in a mouse peritonitis model. Our combined results led to the identification of 81 in vivo activated genes. Among them, the ef_3196/7 operon was shown to be strongly induced in the insect host model. Deletion of this operonic structure demonstrated that this two-component system was essential to the E. faecalis pathogenic potential in Galleria. Gene ef_0377, induced in insect and mammalian models, has also been further analyzed and it has been demonstrated that this ankyrin-encoding gene was also involved in E. faecalis virulence. Thus these R-IVET screenings led to the identification of new E. faecalis factors implied in in vivo persistence and pathogenic potential of this opportunistic pathogen.
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Affiliation(s)
- Aurelie Hanin
- Laboratoire de Microbiologie de l'Environnement, EA956 USC INRA2017, Université de Caen, Caen, France
| | - Irina Sava
- Division of Infection Diseases, Department of Medicine, University Medical Center, Freiburg, Germany
| | - YinYin Bao
- Division of Infection Diseases, Department of Medicine, University Medical Center, Freiburg, Germany
| | - Johannes Huebner
- Division of Infection Diseases, Department of Medicine, University Medical Center, Freiburg, Germany
| | - Axel Hartke
- Laboratoire de Microbiologie de l'Environnement, EA956 USC INRA2017, Université de Caen, Caen, France
| | - Yanick Auffray
- Laboratoire de Microbiologie de l'Environnement, EA956 USC INRA2017, Université de Caen, Caen, France
| | - Nicolas Sauvageot
- Laboratoire de Microbiologie de l'Environnement, EA956 USC INRA2017, Université de Caen, Caen, France
- * E-mail:
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Zhang Q, Xu SX, Wang H, Xu WC, Zhang XM, Wu KF, Liu L, Yin YB. Contribution of ClpE to virulence of Streptococcus pneumoniae. Can J Microbiol 2010; 55:1187-94. [PMID: 19935891 DOI: 10.1139/w09-078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ATP-dependent caseinolytic proteases (Clp) play a fundamental role in stress tolerance and virulence in many pathogenic bacteria. Although ClpE of Streptococcus pneumoniae is required for growth at high temperatures, little is known about the role of ClpE in pathogenesis. In this study, we observed that the virulence of the clpE mutant of S. pneumoniae strain D39 was strongly reduced in a mouse intraperitoneal infection model. The clpE mutant also showed substantially reduced adherence to the human lung epithelial carcinoma A549 cell line and human umbilical-vein-derived endothelial cells. The underlying mechanism of virulence attenuation induced by the mutation of clpE was further investigated with real-time RT-PCR and 2-dimensional protein gel analysis. The results indicate that ClpE affects pneumococcal pathogenesis by modulating the expression of some important virulence determinants and metabolism-related factors in S. pneumoniae.
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Affiliation(s)
- Qun Zhang
- Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, P. R. China
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28
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Two Spx proteins modulate stress tolerance, survival, and virulence in Streptococcus mutans. J Bacteriol 2010; 192:2546-56. [PMID: 20233935 DOI: 10.1128/jb.00028-10] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Previous work suggested that the underlying mechanisms by which the Streptococcus mutans ClpXP protease affects virulence traits are associated with accumulation of two orthologues of the Spx regulator, named SpxA and SpxB. Here, a thorough characterization of strains lacking the spx genes (Delta spxA, Delta spxB, and Delta spxA Delta spxB) revealed that Spx, indeed, participates in the regulation of processes associated with S. mutans pathogenesis. The Delta spxA strain displayed impaired ability to grow under acidic and oxidative stress conditions and had diminished long-term viability at low pH. Although the Delta spxB strain did not show any inherent stress-sensitive phenotype, the phenotypes observed in Delta spxA were more pronounced in the Delta spxA Delta spxB double mutant. By using two in vivo models, we demonstrate for the first time that Spx is required for virulence in a gram-positive pathogen. Microarrays confirmed the global regulatory role of SpxA and SpxB. In particular, SpxA was shown to positively regulate genes associated with oxidative stress, a finding supported by enzymatic assays. SpxB had a secondary role in regulation of oxidative stress genes but appeared to play a larger role in controlling processes associated with cell wall homeostasis. Given the high degree of conservation between Spx proteins of low-GC gram-positive bacteria, these results are likely to have broad implications.
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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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Abstract
CtsR is the global transcriptional regulator of the core protein quality networks in low GC, Gram+ bacteria. Balancing these networks during environmental stress is of considerable importance for moderate survival of the bacteria, and also for virulence of pathogenic species. Therefore, inactivation of the CtsR repressor is one of the major cellular responses for fast and efficient adaptation to different protein stress conditions. Historically, CtsR inactivation was mainly studied for the heat stress response, and recently it has been shown that CtsR is an intrinsic thermosensor. Moreover, it has been demonstrated that CtsR degradation is regulated by a two-step mechanism during heat stress, dependent on the arginine kinase activity of McsB. Interestingly, CtsR is also inactivated during oxidative stress, but by a thiol-dependent regulatory pathway. These observations suggest that dual activity control of CtsR activity has developed during the course of evolution.
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Affiliation(s)
- Alexander K W Elsholz
- Ernst-Moritz-Arndt-University Greifswald, Institute of Microbiology, Greifswald, Germany
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31
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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: 126] [Impact Index Per Article: 8.4] [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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Hendriksen WT, Bootsma HJ, van Diepen A, Estevão S, Kuipers OP, de Groot R, Hermans PWM. Strain-specific impact of PsaR of Streptococcus pneumoniae on global gene expression and virulence. MICROBIOLOGY-SGM 2009; 155:1569-1579. [PMID: 19372167 DOI: 10.1099/mic.0.025072-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Previous studies have indicated that PsaR of Streptococcus pneumoniae is a manganese-dependent regulator, negatively affecting the expression of at least seven genes. Here, we extended these observations by transcriptome and proteome analysis of psaR mutants in strains D39 and TIGR4. The microarray analysis identified three shared PsaR targets: the psa operon, pcpA and prtA. In addition, we found 31 genes to be regulated by PsaR in D39 only, most strikingly a cellobiose-specific phosphotransferase system (PTS) and a putative bacteriocin operon (sp0142-sp0146). In TIGR4, 14 PsaR gene targets were detected, with the rlrA pathogenicity islet being the most pronounced. Proteomics confirmed most of the shared gene targets. To examine the contribution of PsaR to pneumococcal virulence, we compared D39 and TIGR4 wild-type (wt) and psaR mutants in three murine infection models. During colonization, no clear effect was observed of the psaR mutation in either D39 or TIGR4. In the pneumonia model, small but significant differences were observed in the lungs of mice infected with either D39wt or DeltapsaR: D39DeltapsaR had an initial advantage in survival in the lungs. Conversely, TIGR4DeltapsaR-infected mice had significantly lower bacterial loads at 24 h only. Finally, during experimental bacteraemia, D39DeltapsaR-infected mice had significantly lower bacterial loads in the bloodstream than wt-infected mice for the first 24 h of infection. TIGR4DeltapsaR showed attenuation at 36 h only. In conclusion, our results show that PsaR of D39 and TIGR4 has a strain-specific role in global gene expression and in the development of bacteraemia in mice.
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Affiliation(s)
- Wouter T Hendriksen
- Department of Pediatrics, Erasmus MC-Sophia Children's Hospital, 3000 DR Rotterdam, The Netherlands
| | - Hester J Bootsma
- Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Angela van Diepen
- Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Silvia Estevão
- Department of Pediatrics, Erasmus MC-Sophia Children's Hospital, 3000 DR Rotterdam, The Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, PO Box 14, 9750 AA Haren, The Netherlands
| | - Ronald de Groot
- Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Peter W M Hermans
- Laboratory of Pediatric Infectious Diseases, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
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Cao J, Li D, Gong Y, Yin N, Chen T, Wong CK, Xu W, Luo J, Zhang X, Lam CWK, Yin Y. Caseinolytic protease: a protein vaccine which could elicit serotype-independent protection against invasive pneumococcal infection. Clin Exp Immunol 2009; 156:52-60. [PMID: 19220325 DOI: 10.1111/j.1365-2249.2008.03866.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Invasive pneumococcal diseases incur significant mortality, morbidity and economic costs. The most effective strategy currently available to reduce the burden of these diseases is vaccination. In this study, we evaluated the protective efficacy of immunizing mice with caseinolytic protease (ClpP) protein antigen whose gene sequences were shown to be highly conserved in different strains of Streptococcus pneumoniae in an invasive-disease model (intraperitoneal infection model), and protection against invasive challenge with 12 different serotypes of S. pneumoniae was assessed in two murine strains. Our findings demonstrated that active immunization with ClpP and passive immunization with antibodies specific for ClpP could elicit serotype-independent protection effectively against invasive pneumococcal infection. Therefore, to our knowledge, this study is the first report that immunization with single pneumococcal ClpP protein antigen could protect against such broad-range pneumococal strains, which thus supports the development of ClpP as a human penumococcal vaccine.
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Affiliation(s)
- J Cao
- Key Laboratory of Diagnostic Medicine designated by the Ministry of Education, Chongqing Medical University, Chongqing, China
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Role of Clp proteins in expression of virulence properties of Streptococcus mutans. J Bacteriol 2009; 191:2060-8. [PMID: 19181818 DOI: 10.1128/jb.01609-08] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mutational analysis revealed that members of the Clp system, specifically the ClpL chaperone and the ClpXP proteolytic complex, modulate the expression of important virulence attributes of Streptococcus mutans. Compared to its parent, the DeltaclpL strain displayed an enhanced capacity to form biofilms in the presence of sucrose, had reduced viability, and was more sensitive to acid killing. The DeltaclpP and DeltaclpX strains displayed several phenotypes in common: slow growth, tendency to aggregate in culture, reduced autolysis, and reduced ability to grow under stress, including acidic pH. Unexpectedly, the DeltaclpP and DeltaclpX mutants were more resistant to acid killing and demonstrated enhanced viability in long-term survival assays. Biofilm formation by the DeltaclpP and DeltaclpX strains was impaired when grown in glucose but enhanced in sucrose. In an animal study, the average number of S. mutans colonies recovered from the teeth of rats infected with the DeltaclpP or DeltaclpX strain was slightly lower than that of the parent strain. In Bacillus subtilis, the accumulation of the Spx global regulator, a substrate of ClpXP, has accounted for the DeltaclpXP phenotypes. Searching the S. mutans genome, we identified two putative spx genes, designated spxA and spxB. The inactivation of either of these genes bypassed phenotypes of the clpP and clpX mutants. Western blotting demonstrated that Spx accumulates in the DeltaclpP and DeltaclpX strains. Our results reveal that the proteolysis of ClpL and ClpXP plays a role in the expression of key virulence traits of S. mutans and indicates that the underlying mechanisms by which ClpXP affect virulence traits are associated with the accumulation of two Spx orthologues.
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Regulation of cyclic lipopeptide biosynthesis in Pseudomonas fluorescens by the ClpP protease. J Bacteriol 2008; 191:1910-23. [PMID: 19114474 DOI: 10.1128/jb.01558-08] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyclic lipopeptides produced by Pseudomonas species exhibit potent surfactant and broad-spectrum antibiotic properties. Their biosynthesis is governed by large multimodular nonribosomal peptide synthetases, but little is known about the genetic regulatory network. This study provides, for the first time, evidence that the serine protease ClpP regulates the biosynthesis of massetolides, cyclic lipopeptides involved in swarming motility, biofilm formation, and antimicrobial activity of Pseudomonas fluorescens SS101. The results show that ClpP affects the expression of luxR(mA), the transcriptional regulator of the massetolide biosynthesis genes massABC, thereby regulating biofilm formation and swarming motility of P. fluorescens SS101. Transcription of luxR(mA) was significantly repressed in the clpP mutant, and introduction of luxR(mA) restored, in part, massetolide biosynthesis and swarming motility of the clpP mutant. Site-directed mutagenesis and expression analyses indicated that the chaperone subunit ClpX and the Lon protease are not involved in regulation of massetolide biosynthesis and are transcribed independently of clpP. Addition of Casamino Acids enhanced the transcription of luxR(mA) and massABC in the clpP mutant, leading to a partial rescue of massetolide production and swarming motility. The results further suggested that, at the transcriptional level, ClpP-mediated regulation of massetolide biosynthesis operates independently of regulation by the GacA/GacS two-component system. The role of amino acid metabolism and the putative mechanisms underlying ClpP-mediated regulation of cyclic lipopeptide biosynthesis, swarming motility, and growth in P. fluorescens are discussed.
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Transcription of clpP is enhanced by a unique tandem repeat sequence in Streptococcus mutans. J Bacteriol 2008; 191:1056-65. [PMID: 19047352 DOI: 10.1128/jb.01436-08] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptococcus mutans, the primary causative agent of human dental caries, contains a single copy of the gene encoding ClpP, the chief intracellular protease responsible for tolerance to various environmental stresses. To better understand the role of ClpP in stress response, we investigated the regulation of clpP expression in S. mutans. Using semiquantitative reverse transcription-PCR analysis, we observed that, under nonstressed conditions, clpP expression is somewhat constant throughout the growth phases, although it gradually decreases as cells enter the late stationary phase. The half-life of the clpP transcript was found to be less than 1 minute. Sequence analysis of the clpP locus reveals the presence of a 50-bp tandem repeat sequence located immediately upstream of the clpP promoter (PclpP). PCR and DNA sequence analyses suggest that the number of tandem repeat units can vary from as few as two to as many as nine, depending on the particular S. mutans isolate. Further analysis, using a transcriptional reporter fusion consisting of PclpP fused to a promoterless gusA gene, indicates that the presence of the repeat sequence region within PclpP results in an approximately fivefold increase in expression from PclpP compared to the repeat-free transcriptional reporter fusion. CtsR, a transcriptional repressor that negatively regulates clpP expression, has no effect on this repeat-mediated induction of clpP transcription. Furthermore, the repeat sequence is not necessary for the induction of clpP under stress conditions. Database searches indicate that the region containing the tandem repeats is absent in the clpP loci in other bacteria, including other closely related Streptococcus spp., suggesting that the repeat sequences are specific for the induction of clpP expression in S. mutans. We speculate that a host-specific transcriptional activator might be involved in the upregulation of clpP expression in S. mutans.
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Loughlin MF, Arandhara V, Okolie C, Aldsworth TG, Jenks PJ. Helicobacter pylori mutants defective in the clpP ATP-dependant protease and the chaperone clpA display reduced macrophage and murine survival. Microb Pathog 2008; 46:53-7. [PMID: 18992803 DOI: 10.1016/j.micpath.2008.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 10/02/2008] [Accepted: 10/07/2008] [Indexed: 11/18/2022]
Abstract
The ATP-dependent caseinolytic proteases (Clp) are important in resistance against environmental stresses, antibiotic treatments and host immune defences for a number of pathogenic bacteria. ClpP is the proteolytic subunit, whilst ClpA acts both as a chaperone and as an ATPase driving the degradation of damaged or mis-made proteins. The gastric pathogen Helicobacter pylori infects approximately half of the world's population and can cause gastric or duodenal ulcers, gastric malignancies and mucosa-associated lymphoid tissue lymphomas. The conditions of its in vivo environment expose the organism to host immune cells and upon treatment, antibiotics, conditions likely to cause protein damage. We generated isogenic nonpolar mutants in strain SS1 of clpP and clpA and double mutants with both genes inactivated. Such mutants showed increased sensitivity to antibacterials causing protein damage and/or oxidative stress, in addition to a reduced survival in human macrophages. In the mouse infection model the double mutant SS1 clpAP lacked all ability to colonize the murine host. This suggests that the ability to recover from protein damage is of key importance in the pathogenesis of this organism.
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Affiliation(s)
- Michael F Loughlin
- Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
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Isolation of Streptococcus pneumoniae biofilm mutants and their characterization during nasopharyngeal colonization. Infect Immun 2008; 76:5049-61. [PMID: 18794289 DOI: 10.1128/iai.00425-08] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Asymptomatic colonization of the nasopharynx by Streptococcus pneumoniae precedes pneumococcal disease, yet pneumococcal colonization factors remain poorly understood. Many bacterial infections involve biofilms which protect bacteria from host defenses and antibiotics. To gain insight into the genetics of biofilm formation by S. pneumoniae, we conducted an in vitro screen for biofilm-altered mutants with the serotype 4 clinical isolate TIGR4. In a first screen of 6,000 mariner transposon mutants, we repeatedly isolated biofilm-overproducing acapsular mutants, suggesting that the capsule was antagonistic to biofilm formation. Therefore, we screened 6,500 additional transposon mutants in an S. pneumoniae acapsular background. Following this approach, we isolated 69 insertions in 49 different genes. The collection of mutants includes genes encoding bona fide and putative choline binding proteins, adhesins, synthases of membrane and cell wall components, extracellular and cell wall proteases, efflux pumps, ABC and PTS transporters, and transcriptional regulators, as well as several conserved and novel hypothetical proteins. Interestingly, while four insertions mapped to rrgA, encoding a subunit of a recently described surface pilus, rrgB and rrgC (encoding the other two pilus subunits) mutants had no biofilm defects, implicating the RrgA adhesin but not the pilus structure per se in biofilm formation. To correlate our findings to the process of colonization, we transferred a set of 29 mutations into the wild-type encapsulated strain and then tested the fitness of the mutants in vivo. Strikingly, we found that 23 of these mutants were impaired for nasopharyngeal colonization, thus establishing a link between biofilm formation and colonization.
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Preston JA, Dockrell DH. Virulence factors in pneumococcal respiratory pathogenesis. Future Microbiol 2008; 3:205-21. [PMID: 18366340 DOI: 10.2217/17460913.3.2.205] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Streptococcus pneumoniae (the pneumococcus) is a major global cause of human disease. Since the publication of the entire sequence of TIGR4 in 2001, our understanding of this human pathogen has increased significantly. Genetic studies, and the use of mutant strains have refined our understanding of the pathogenic mechanisms of classic pneumococcal virulence factors, including the polysaccharide capsule, pneumolysin and surface-expressed proteins. Genetic screens are identifying novel virulence factors. Characterization of pili and bacteriocins, as well as genes associated with competence, metabolism and resistance to oxidative stress has provided new insights into the genetic diversity of the pneumococcus. Further appreciation of the molecular basis of pneumococcal pathogenesis will lead to more effective strategies for the prevention and management of pneumococcal disease.
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Affiliation(s)
- Julie A Preston
- Section of Infection, Inflammation & Immunity, L-Floor, University of Sheffield School of Medicine & Biomedical Sciences, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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Böttcher T, Sieber SA. Beta-lactones as privileged structures for the active-site labeling of versatile bacterial enzyme classes. Angew Chem Int Ed Engl 2008; 47:4600-3. [PMID: 18383487 DOI: 10.1002/anie.200705768] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Thomas Böttcher
- Center for integrated Protein Science Munich, Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 Munich, Germany
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Böttcher T, Sieber S. β-Lactone als privilegierte Strukturen für die Markierung des aktiven Zentrums vielfältiger bakterieller Enzymklassen. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705768] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Frees D, Savijoki K, Varmanen P, Ingmer H. Clp ATPases and ClpP proteolytic complexes regulate vital biological processes in low GC, Gram-positive bacteria. Mol Microbiol 2007; 63:1285-95. [PMID: 17302811 DOI: 10.1111/j.1365-2958.2007.05598.x] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Clp proteolytic complexes consisting of a proteolytic core flanked by Clp ATPases are widely conserved in bacteria, and their biological roles have received considerable interest. In particular, mutants in the clp genes in the low-GC-content Gram-positive phyla Bacillales and Lactobacillales display a diverse range of phenotypic changes including general stress sensitivity, aberrant cell morphology, failure to initiate developmental programs, and for pathogens, severely attenuated virulence. Extensive research dedicated to unravelling the molecular mechanisms underlying these complex phenotypes has led to fascinating new insights that will be covered by this review. First, Clp ATPases and ClpP-containing proteolytic complexes play indispensable roles in cellular protein quality control systems by refolding or degrading damaged proteins in both stressed and non-stressed cells. Secondly, ClpP proteases and the chaperone activity of Clp ATPases are important for controlling stability and activity of central transcriptional regulators, thereby exerting tremendous impact on cell physiology. Targets include major stress regulators like Spx (oxidative stress), the antisigma factor RsiW (alkaline stress) and HdiR (DNA damage) in addition to regulators of developmental programs like ComK (competence development), sigmaH and Sda (sporulation). Thus, Clp proteins are central in co-ordinating developmental decisions and stress response in low GC Gram-positive bacteria.
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Affiliation(s)
- Dorte Frees
- Department of Veterinary Pathobiology, Faculty of Life Sciences, University of Copenhagen, Stigbøjlen 4, DK-1870 Frederiksberg C, Denmark
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Contribution of conserved ATP-dependent proteases of Campylobacter jejuni to stress tolerance and virulence. Appl Environ Microbiol 2007; 73:7803-13. [PMID: 17933920 DOI: 10.1128/aem.00698-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In prokaryotic cells the ATP-dependent proteases Lon and ClpP (Clp proteolytic subunit) are involved in the turnover of misfolded proteins and the degradation of regulatory proteins, and depending on the organism, these proteases contribute variably to stress tolerance. We constructed mutants in the lon and clpP genes of the food-borne human pathogen Campylobacter jejuni and found that the growth of both mutants was impaired at high temperature, a condition known to increase the level of misfolded protein. Moreover, the amounts of misfolded protein aggregates were increased when both proteases were absent, and we propose that both ClpP and Lon are involved in eliminating misfolded proteins in C. jejuni. In order to bind misfolded protein, ClpP has to associate with one of several Clp ATPases. Following inactivation of the ATPase genes clpA and clpX, only the clpX mutant displayed the same heat sensitivity as the clpP mutant, indicating that the ClpXP proteolytic complex is responsible for the degradation of heat-damaged proteins in C. jejuni. Notably, ClpP and ClpX are required for growth at 42 degrees C, which is the temperature of the intestinal tract of poultry, one of the primary carriers of C. jejuni. Thus, ClpP and ClpX may be suitable targets of new intervention strategies aimed at reducing C. jejuni in poultry production. Further characterization of the clpP and lon mutants revealed other altered phenotypes, such as reduced motility, less autoagglutination, and lower levels of invasion of INT407 epithelial cells, suggesting that the proteases may contribute to the virulence of C. jejuni.
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Anisimova M, Bielawski J, Dunn K, Yang Z. Phylogenomic analysis of natural selection pressure in Streptococcus genomes. BMC Evol Biol 2007; 7:154. [PMID: 17760998 PMCID: PMC2031904 DOI: 10.1186/1471-2148-7-154] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 08/30/2007] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND In comparative analyses of bacterial pathogens, it has been common practice to discriminate between two types of genes: (i) those shared by pathogens and their non-pathogenic relatives (core genes), and (ii) those found exclusively in pathogens (pathogen-specific accessory genes). Rather than attempting to a priori delineate genes into sets more or less relevant to pathogenicity, we took a broad approach to the analysis of Streptococcus species by investigating the strength of natural selection in all clusters of homologous genes. The genus Streptococcus is comprised of a wide variety of both pathogenic and commensal lineages, and we relate our findings to the pre-existing knowledge of Streptococcus virulence factors. RESULTS Our analysis of 1730 gene clusters revealed 136 cases of positive Darwinian selection, which we suggest is most likely to result from an antagonistic interaction between the host and pathogen at the molecular level. A two-step validation procedure suggests that positive selection was robustly identified in our genomic survey. We found no evidence to support the notion that pathogen specific accessory genes are more likely to be subject to positive selection than core genes. Indeed, we even uncovered a few cases of essential gene evolution by positive selection. Among the gene clusters subject to positive selection, a large fraction (29%) can be connected to virulence. The most striking finding was that a considerable fraction of the positively selected genes are also known to have tissue specific patterns of expression during invasive disease. As current expression data is far from comprehensive, we suggest that this fraction was underestimated. CONCLUSION Our findings suggest that pathogen specific genes, although a popular focus of research, do not provide a complete picture of the evolutionary dynamics of virulence. The results of this study, and others, support the notion that the products of both core and accessory genes participate in complex networks that comprise the molecular basis of virulence. Future work should seek to understand the evolutionary dynamics of both core and accessory genes as a function of the networks in which they participate.
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Affiliation(s)
- Maria Anisimova
- Department of Biology, University College London, London, UK
| | - Joseph Bielawski
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Katherine Dunn
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ziheng Yang
- Department of Biology, University College London, London, UK
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Regev-Yochay G, Trzcinski K, Thompson CM, Lipsitch M, Malley R. SpxB is a suicide gene of Streptococcus pneumoniae and confers a selective advantage in an in vivo competitive colonization model. J Bacteriol 2007; 189:6532-9. [PMID: 17631628 PMCID: PMC2045178 DOI: 10.1128/jb.00813-07] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human bacterial pathogen Streptococcus pneumoniae dies spontaneously upon reaching stationary phase. The extent of S. pneumoniae death at stationary phase is unusual in bacteria and has been conventionally attributed to autolysis by the LytA amidase. In this study, we show that spontaneous pneumococcal death is due to hydrogen peroxide (H(2)O(2)), not LytA, and that the gene responsible for H(2)O(2) production (spxB) also confers a survival advantage in colonization. Survival of S. pneumoniae in stationary phase was significantly prolonged by eliminating H(2)O(2) in any of three ways: chemically by supplementing the media with catalase, metabolically by growing the bacteria under anaerobic conditions, or genetically by constructing DeltaspxB mutants that do not produce H(2)O(2). Likewise, addition of H(2)O(2) to exponentially growing S. pneumoniae resulted in a death rate similar to that of cells in stationary phase. While DeltalytA mutants did not lyse at stationary phase, they died at a rate similar to that of the wild-type strain. Furthermore, we show that the death process induced by H(2)O(2) has features of apoptosis, as evidenced by increased annexin V staining, decreased DNA content, and appearance as assessed by transmission electron microscopy. Finally, in an in vivo rat model of competitive colonization, the presence of spxB conferred a selective advantage over the DeltaspxB mutant, suggesting an explanation for the persistence of this gene. We conclude that a suicide gene of pneumococcus is spxB, which induces an apoptosis-like death in pneumococci and confers a selective advantage in nasopharyngeal cocolonization.
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Affiliation(s)
- Gili Regev-Yochay
- Department of Epidemiology and Department of Immunology and Infectious Diseases, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115, USA.
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Cao J, Chen D, Xu W, Chen T, Xu S, Luo J, Zhao Q, Liu B, Wang D, Zhang X, Shan Y, Yin Y. Enhanced protection against pneumococcal infection elicited by immunization with the combination of PspA, PspC, and ClpP. Vaccine 2007; 25:4996-5005. [PMID: 17524530 DOI: 10.1016/j.vaccine.2007.04.069] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 04/07/2007] [Accepted: 04/20/2007] [Indexed: 11/20/2022]
Abstract
Immunization with a combination of several virulence-associated proteins is one of the strategies of developing effective protein-based vaccines to enhance the protection against Streptococcus pneumoniae. In this study, we evaluated the protection effects against pneumococcal infection caused by S. pneumoniae TIGR4 in BALB/c mice immunized with either single pneumococcal surface protein A (PspA), pneumococcal surface protein C (PspC), the caseinolytic protease (ClpP) or their combinations. The median survival times for mice immunized with single antigen or their combinations were significantly longer than that for mice treated with adjuvant alone. Mice treated with a combination of three antigens survived significantly longer than those that received either single or two antigens. The highest survival rate of the various groups of mice was observed with the combination of three antigens, this survival rate was significantly different from those for mice that received either single antigen or the combinations of two antigens except the mixture of ClpP and PspA. In the experiment of passive immunization with hyperimmune serums containing their specific polyclonal antibodies (anti-PspA serum, anti-PspC serum, anti-ClpP serum), the median survival times for mice immunized with hyperimmune serums containing specific polyclonal antibodies were significantly longer than that for control mice, the treatment of serum containing only one single polyclonal antibody could not provide higher survival rate than control serum. However, the survival rates for mice treated with the serums containing combined polyclonal antibodies were significantly higher than those for mice treated with either control serum or anti-PspA serum alone. Immunization with the combination of three hyperimmune serums also provided the best protection against S. pneumoniae. Compared to mice treated with serum containing single polyclonal antibody, the survival rate for mice treated with serums containing three polyclonal antibodies was significantly higher but was not different from those for mice treated with serums containing two polyclonal antibodies. Our findings provided evidence that a mixture of PspA, PspC, and ClpP or their polyclonal antibodies could enhance the protection against pneumococcal infection acting a synergetic effect.
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Affiliation(s)
- Ju Cao
- Key Laboratory of Laboratory Medical Diagnostics of Ministry of Education, Department of Laboratory Medicine in Chongqing Medical University, Chongqing 400016, PR China
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47
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Tu LN, Jeong HY, Kwon HY, Ogunniyi AD, Paton JC, Pyo SN, Rhee DK. Modulation of adherence, invasion, and tumor necrosis factor alpha secretion during the early stages of infection by Streptococcus pneumoniae ClpL. Infect Immun 2007; 75:2996-3005. [PMID: 17403879 PMCID: PMC1932908 DOI: 10.1128/iai.01716-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Heat shock proteins (HSPs) play a pivotal role as chaperones in the folding of native and denatured proteins and can help pathogens penetrate host defenses. However, the underlying mechanism(s) of modulation of virulence by HSPs has not been fully determined. In this study, the role of the chaperone ClpL in the pathogenicity of Streptococcus pneumoniae was assessed. A clpL mutant adhered to and invaded nasopharyngeal or lung cells much more efficiently than the wild type adhered to and invaded these cells in vitro, as well as in vivo, although it produced the same amount of capsular polysaccharide. However, the level of secretion of tumor necrosis factor alpha (TNF-alpha) from macrophages infected with the clpL mutant was significantly lower than the level of secretion elicited by the wild type during the early stages of infection. Interestingly, treatment of the human lung epithelial carcinoma A549 and murine macrophage RAW 264.7 cell lines with cytochalasin D, an inhibitor of actin polymerization, increased adherence of the mutant to the host cells. In contrast, cytochalasin D treatment of RAW 264.7 cells decreased TNF-alpha secretion after infection with either the wild type or the mutant. However, pretreatment of cell lines with the actin polymerization activator jasplakinolide reversed these phenotypes. These findings indicate, for the first time, that the ClpL chaperone represses adherence of S. pneumoniae to host cells and induces secretion of TNF-alpha via a mechanism dependent upon actin polymerization during the initial infection stage.
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Affiliation(s)
- Le Nhat Tu
- College of Pharmacy, Sungkyunkwan University, Suwon 440-746, South Korea.
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48
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Delvecchio VG, Connolly JP, Alefantis TG, Walz A, Quan MA, Patra G, Ashton JM, Whittington JT, Chafin RD, Liang X, Grewal P, Khan AS, Mujer CV. Proteomic profiling and identification of immunodominant spore antigens of Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis. Appl Environ Microbiol 2006; 72:6355-63. [PMID: 16957262 PMCID: PMC1563598 DOI: 10.1128/aem.00455-06] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Differentially expressed and immunogenic spore proteins of the Bacillus cereus group of bacteria, which includes Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis, were identified. Comparative proteomic profiling of their spore proteins distinguished the three species from each other as well as the virulent from the avirulent strains. A total of 458 proteins encoded by 232 open reading frames were identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis for all the species. A number of highly expressed proteins, including elongation factor Tu (EF-Tu), elongation factor G, 60-kDa chaperonin, enolase, pyruvate dehydrogenase complex, and others exist as charge variants on two-dimensional gels. These charge variants have similar masses but different isoelectric points. The majority of identified proteins have cellular roles associated with energy production, carbohydrate transport and metabolism, amino acid transport and metabolism, posttranslational modifications, and translation. Novel vaccine candidate proteins were identified using B. anthracis polyclonal antisera from humans postinfected with cutaneous anthrax. Fifteen immunoreactive proteins were identified in B. anthracis spores, whereas 7, 14, and 7 immunoreactive proteins were identified for B. cereus and in the virulent and avirulent strains of B. thuringiensis spores, respectively. Some of the immunodominant antigens include charge variants of EF-Tu, glyceraldehyde-3-phosphate dehydrogenase, dihydrolipoamide acetyltransferase, Delta-1-pyrroline-5-carboxylate dehydrogenase, and a dihydrolipoamide dehydrogenase. Alanine racemase and neutral protease were uniquely immunogenic to B. anthracis. Comparative analysis of the spore immunome will be of significance for further nucleic acid- and immuno-based detection systems as well as next-generation vaccine development.
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MESH Headings
- Antigens, Bacterial/genetics
- Antigens, Bacterial/isolation & purification
- Bacillus anthracis/chemistry
- Bacillus anthracis/genetics
- Bacillus anthracis/immunology
- Bacillus cereus/chemistry
- Bacillus cereus/genetics
- Bacillus cereus/immunology
- Bacillus thuringiensis/chemistry
- Bacillus thuringiensis/genetics
- Bacillus thuringiensis/immunology
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Bacterial Proteins/isolation & purification
- Electrophoresis, Gel, Two-Dimensional
- Genes, Bacterial
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/isolation & purification
- Open Reading Frames
- Proteomics
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Spores, Bacterial/chemistry
- Spores, Bacterial/genetics
- Spores, Bacterial/immunology
- Virulence/immunology
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Graham MR, Virtaneva K, Porcella SF, Gardner DJ, Long RD, Welty DM, Barry WT, Johnson CA, Parkins LD, Wright FA, Musser JM. Analysis of the transcriptome of group A Streptococcus in mouse soft tissue infection. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 169:927-42. [PMID: 16936267 PMCID: PMC1698835 DOI: 10.2353/ajpath.2006.060112] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Molecular mechanisms mediating group A Streptococcus (GAS)-host interactions remain poorly understood but are crucial for diagnostic, therapeutic, and vaccine development. An optimized high-density microarray was used to analyze the transcriptome of GAS during experimental mouse soft tissue infection. The transcriptome of a wild-type serotype M1 GAS strain and an isogenic transcriptional regulator knockout mutant (covR) also were compared. Array datasets were verified by quantitative real-time reverse transcriptase-polymerase chain reaction and in situ immunohistochemistry. The results unambiguously demonstrate that coordinated expression of proven and putative GAS virulence factors is directed toward overwhelming innate host defenses leading to severe cellular damage. We also identified adaptive metabolic responses triggered by nutrient signals and hypoxic/acidic conditions in the host, likely facilitating pathogen persistence and proliferation in soft tissues. Key discoveries included that oxidative stress genes, virulence genes, genes related to amino acid and maltodextrin utilization, and several two-component transcriptional regulators were highly expressed in vivo. This study is the first global analysis of the GAS transcriptome during invasive infection. Coupled with parallel analysis of the covR mutant strain, novel insights have been made into the regulation of GAS virulence in vivo, resulting in new avenues for targeted therapeutic and vaccine research.
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Affiliation(s)
- Morag R Graham
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Veterinary Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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50
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Lanie JA, Ng WL, Kazmierczak KM, Andrzejewski TM, Davidsen TM, Wayne KJ, Tettelin H, Glass JI, Winkler ME. Genome sequence of Avery's virulent serotype 2 strain D39 of Streptococcus pneumoniae and comparison with that of unencapsulated laboratory strain R6. J Bacteriol 2006; 189:38-51. [PMID: 17041037 PMCID: PMC1797212 DOI: 10.1128/jb.01148-06] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Streptococcus pneumoniae (pneumococcus) is a leading human respiratory pathogen that causes a variety of serious mucosal and invasive diseases. D39 is an historically important serotype 2 strain that was used in experiments by Avery and coworkers to demonstrate that DNA is the genetic material. Although isolated nearly a century ago, D39 remains extremely virulent in murine infection models and is perhaps the strain used most frequently in current studies of pneumococcal pathogenesis. To date, the complete genome sequences have been reported for only two S. pneumoniae strains: TIGR4, a recent serotype 4 clinical isolate, and laboratory strain R6, an avirulent, unencapsulated derivative of strain D39. We report here the genome sequences and new annotation of two different isolates of strain D39 and the corrected sequence of strain R6. Comparisons of these three related sequences allowed deduction of the likely sequence of the D39 progenitor and mutations that arose in each isolate. Despite its numerous repeated sequences and IS elements, the serotype 2 genome has remained remarkably stable during cultivation, and one of the D39 isolates contains only five relatively minor mutations compared to the deduced D39 progenitor. In contrast, laboratory strain R6 contains 71 single-base-pair changes, six deletions, and four insertions and has lost the cryptic pDP1 plasmid compared to the D39 progenitor strain. Many of these mutations are in or affect the expression of genes that play important roles in regulation, metabolism, and virulence. The nature of the mutations that arose spontaneously in these three strains, the relative global transcription patterns determined by microarray analyses, and the implications of the D39 genome sequences to studies of pneumococcal physiology and pathogenesis are presented and discussed.
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Affiliation(s)
- Joel A Lanie
- Department of Biology, Indiana University Bloomington, Jordan Hall 142, Bloomington, IN 47405, USA
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