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Lu L, Qi Z, Chen Z, Wang H, Wei X, Zhao B, Wang Z, Shao Y, Tu J, Song X. Avian pathogenic Escherichia coli T6SS effector protein Hcp2a causes mitochondrial dysfunction through interaction with LETM1 protein in DF-1 cells. Poult Sci 2024; 103:103514. [PMID: 38367471 PMCID: PMC10879833 DOI: 10.1016/j.psj.2024.103514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/25/2024] [Accepted: 01/25/2024] [Indexed: 02/19/2024] Open
Abstract
The type VI secretion system (T6SS) of avian pathogenic Escherichia coli (APEC) can affect the functions of eukaryotic cells by secreting or injecting effectors. Hemolysin co-regulatory protein (Hcp), one of the markers of the T6SS, is both a structural protein and an effector protein of the T6SS. According to previous studies, mitochondria in eukaryotic cells are targeted by pathogenic bacteria. However, little is known about the regulation of mitochondria in eukaryotic host cells by the T6SS effector protein Hcp of APEC. In our study, DF-1 cells co-incubated with Hcp2a protein for 6 h showed decreased mitochondrial membrane potential, increased Ca2+ concentration, and increased cellular reactive oxygen species (ROS) levels. We therefore conclude that Hcp2a protein causes dysfunction to mitochondria in DF-1 cells. To explain the mechanism that causes mitochondrial dysfunction, we reanalyzed the Hcp2a interaction protein dataset in DF-1 cells, and the Leucine zipper EF-hand-containing transmembrane protein 1 (LETM1), which is associated with mitochondria, was screened. The protein and molecular docking results showed that Hcp2a protein and LETM1 protein have better binding. Finally, subcellular localization results showed that Hcp2a was localized to mitochondria. In summary, Hcp2a effector proteins caused dysfunction to DF-1 cellular mitochondria, and we hypothesize that the interaction of Hcp2a protein with LETM1 protein induces mitochondrial dysfunction and promotes mitochondrial localization of Hcp2a in DF-1 cells.
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Affiliation(s)
- Liting Lu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Zhao Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Zhe Chen
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Haiyang Wang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Xiyang Wei
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Bingyu Zhao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Zhenyu Wang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Joint Research Center for Food Nutrition and Health of IHM, Anhui Agricultural University, Hefei, PR China
| | - Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Anhui Province Engineering Laboratory for Animal Food Quality and Bio-Safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China; Joint Research Center for Food Nutrition and Health of IHM, Anhui Agricultural University, Hefei, PR China.
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Guckes KR, Yount TA, Steingard CH, Miyashiro TI. Quorum sensing inhibits interference competition among bacterial symbionts within a host. Curr Biol 2023; 33:4244-4251.e4. [PMID: 37689064 PMCID: PMC10592073 DOI: 10.1016/j.cub.2023.08.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/20/2023] [Accepted: 08/16/2023] [Indexed: 09/11/2023]
Abstract
The symbioses that animals form with bacteria play important roles in health and disease, but the molecular details underlying how bacterial symbionts initially assemble within a host remain unclear.1,2,3 The bioluminescent bacterium Vibrio fischeri establishes a light-emitting symbiosis with the Hawaiian bobtail squid Euprymna scolopes by colonizing specific epithelium-lined crypt spaces within a symbiotic organ called the light organ.4 Competition for these colonization sites occurs between different strains of V. fischeri, with the lancet-like type VI secretion system (T6SS) facilitating strong competitive interference that results in strain incompatibility within a crypt space.5,6 Although recent studies have identified regulators of this T6SS, how the T6SS is controlled as symbionts assemble in vivo remains unknown.7,8 Here, we show that T6SS activity is suppressed by N-octanoyl-L-homoserine lactone (C8 HSL), which is a signaling molecule that facilitates quorum sensing in V. fischeri and is important for efficient symbiont assembly.9,10 We find that this signaling depends on the quorum-sensing regulator LitR, which lowers expression of the needle subunit Hcp, a key component of the T6SS, by repressing transcription of the T6SS regulator VasH. We show that LitR-dependent quorum sensing inhibits strain incompatibility within the squid light organ. Collectively, these results provide new insights into the mechanisms by which regulatory networks that promote symbiosis also control competition among symbionts, which in turn may affect the overall symbiont diversity that assembles within a host.
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Affiliation(s)
- Kirsten R Guckes
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Taylor A Yount
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Caroline H Steingard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Tim I Miyashiro
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA; The One Health Microbiome Center, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
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Chen Z, Qi Z, Li Z, Song Z, Wang X, Shao Y, Tu J, Song X. Effector protein Hcp2a of avian pathogenic Escherichia coli interacts with the endoplasmatic reticulum associated RPL23 protein of chicken DF-1 fibroblasts. Vet Res 2023; 54:6. [PMID: 36717947 DOI: 10.1186/s13567-023-01138-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 01/06/2023] [Indexed: 01/31/2023] Open
Abstract
The type VI secretion system (T6SS) is a secretion apparatus widely found in pathogenic Gram-negative bacteria and is important for competition among various bacteria and host cell pathogenesis. Hcp is a core component of functional T6SS and transports toxic effectors into target cells by assembling to form tube-like structures. Studies have shown that Hcp simultaneously acts as an effector to influence cellular physiological activities; however, the mechanism of its activity in host cells remains unclear. To investigate the target of effector protein Hcp2a in a chicken fibroblast cell line, we first detected the subcellular localization of Hcp2a in DF-1 cells by indirect immunofluorescence assay. The results showed that Hcp2a protein was localized in the endoplasmic reticulum of DF-1 cells. We also used a streptavidin-biotin affinity pull-down assay combined with LC-MS/MS to screen DF-1 cell lysates for proteins that interact with Hcp2a and analyze the cellular functional pathways affected by them. The results showed that Hcp2a interacted with 52 DF-1 cellular proteins that are involved in multiple intracellular pathways. To further explore the mechanism of Hcp2a protein targeting the endoplasmic reticulum of DF-1 cells, we screened three endoplasmic reticulum-associated proteins (RSL1D1, RPS3A, and RPL23) from 52 prey proteins of Hcp2a for protein-protein molecular docking analysis. The docking analysis showed that the effector protein Hcp2a and the RPL23 protein had good complementarity. Overall, we propose that Hcp2a has strong binding activity to the RPL23 protein in DF-1 cells and this may help Hcp2a anchor to the endoplasmic reticulum in DF-1 cells.
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Tu J, Shen X, Chen Z, Hou M, Song Z, Jiang H, Shao Y, Qi K, Song X. Hcp2b of T6SS affects colonization of Avian pathogenic Escherichia coli and host keratin filament expression. Avian Pathol 2022; 51:154-163. [PMID: 35076320 DOI: 10.1080/03079457.2022.2031881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
T6SS (type VI secretion system) is a kind of nano syringe that exists in APEC (Avian pathogenic Escherichia coli). Hcp (haemolysin-coregulated protein) of T6SS participates in the regulation of virulence during APEC infection. However, whether hcp plays a role in bacterial colonization by expressing in host cells remains unclear. In this study, we analysed the biological characteristics of the mutant hcp2b strain. Our results showed that the hcp2b gene was involved in the regulation of bacterial motility, biofilm formation, anti-serum and anti-oxidative stress. Moreover, our data indicate that the colonization of the hcp2b mutation strain (Δhcp2b) in the lung, liver and kidney of chickens decreased significantly. Hence, overexpression of Hcp2b protein in DF-1 cells was used to analyse the effect of Hcp2b on colonization of APEC. Proteomics analysis showed that overexpression of Hcp2b induced differentially expressed proteins of DF-1 cells (230 were significantly upregulated and 96 were significantly downregulated) and differentially expressed proteins were enriched in keratin filament item. In conclusion, our data indicated that hcp2b promoted the colonization of APEC by affecting the expression of keratin filament.
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Affiliation(s)
- Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Xiao Shen
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Zhe Chen
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Manman Hou
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Zichao Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Huyan Jiang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Anhui Province Engineering Laboratory for Animal Food Quality and Bio-safety, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.,Key Laboratory for Agri-Food Safety, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, PR China
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Massier S, Robin B, Mégroz M, Wright A, Harper M, Hayes B, Cosette P, Broutin I, Boyce JD, Dé E, Hardouin J. Phosphorylation of Extracellular Proteins in Acinetobacter baumannii in Sessile Mode of Growth. Front Microbiol 2021; 12:738780. [PMID: 34659171 PMCID: PMC8517400 DOI: 10.3389/fmicb.2021.738780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/30/2021] [Indexed: 11/21/2022] Open
Abstract
Acinetobacter baumannii is a problematic nosocomial pathogen owing to its increasing resistance to antibiotics and its great ability to survive in the hospital environment, which is linked to its capacity to form biofilms. Structural and functional investigations of post-translational modifications, such as phosphorylations, may lead to identification of candidates for therapeutic targets against this pathogen. Here, we present the first S/T/Y phosphosecretome of two A. baumannii strains, the reference strain ATCC 17978 and the virulent multi-drug resistant strain AB0057, cultured in two modes of growth (planktonic and biofilm) using TiO2 chromatography followed by high resolution mass spectrometry. In ATCC 17978, we detected a total of 137 (97 phosphoproteins) and 52 (33 phosphoproteins) phosphosites in biofilm and planktonic modes of growth, respectively. Similarly, in AB0057, 155 (119 phosphoproteins) and 102 (74 phosphoproteins) phosphosites in biofilm and planktonic modes of growth were identified, respectively. Both strains in the biofilm mode of growth showed a higher number of phosphosites and phosphoproteins compared to planktonic growth. Several phosphorylated sites are localized in key regions of proteins involved in either drug resistance (β-lactamases), adhesion to host tissues (pilins), or protein secretion (Hcp). Site-directed mutagenesis of the Hcp protein, essential for type VI secretion system-mediated interbacterial competition, showed that four of the modified residues are essential for type VI secretion system activity.
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Affiliation(s)
- Sébastien Massier
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | - Brandon Robin
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Marianne Mégroz
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Amy Wright
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Marina Harper
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Brooke Hayes
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Pascal Cosette
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
| | | | - John D. Boyce
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Emmanuelle Dé
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
| | - Julie Hardouin
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, Polymers, Biopolymers, Surfaces Laboratory, Rouen, France
- PISSARO Proteomic Facility, IRIB, Mont-Saint-Aignan, France
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Liao W, Huang HH, Huang QS, Fang-Ling D, Dan Wei D, La-Gen W, Xiang TX, Zhang W, Liu Y. Distribution of type VI secretion system (T6SS) in clinical Klebsiella pneumoniae strains from a Chinese hospital and its potential relationship with virulence and drug resistance. Microb Pathog 2021;:105085. [PMID: 34252554 DOI: 10.1016/j.micpath.2021.105085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The type VI secretion system (T6SS) in Klebsiella pneumoniae strains isolated from the bloodstream, intestinal, the pyogenic liver abscess has been reported. Here we aimed to characterize T6SS in 248 Klebsiella pneumoniae isolates with all kinds of specimens from a Chinese hospital and to investigate the potential association of T6SS with virulence and drug resistance. METHODS T6SS genes, capsular serotyping genes, drug resistance genes, and virulence genes were identified by polymerase chain reaction (PCR). Antibiotic susceptibilities were examined by the disk diffusion method. To assess biofilm formation of these clinical Klebsiella pneumoniae isolates, 96-well microtiter plate assays were performed. MLST was used to analyze the genotypes of these Klebsiella pneumoniae isolates. RESULTS The frequency of T6SS genes among the clinical Klebsiella pneumoniae isolates was 72.2%. The T6SS-positive isolates displayed higher resistance to piperacillin-tazobactam, ciprofloxacin, levofloxacin, meropenem than the T6SS-negative isolates (P < 0.05). The T6SS-positive isolates formed significantly more biofilm mass than the T6SS-negative isolates (mean ± standard deviation [SD], 0.3 ± 0.09 vs.0.16 ± 0.06; P < 0.01). Compared to the T6SS-negative isolates, the T6SS-positive isolates had a higher frequency of virulence genes (rmpA, fimH, entB, kfu, ybtS) and the pLVPK-like plasmid (P < 0.05). CONCLUSION In conclusion, the prevalence of the type VI secretion system is high in clinical Klebsiella pneumoniae isolates in a Chinese teaching hospital. T6SS-positive strains show higher biofilm-forming activity with high drug resistance and exhibit higher virulence potential.
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Kalindamar S, Abdelhamed H, Kordon AO, Pinchuk LM, Karsi A. Hemolysin Co-regulated Family Proteins Hcp1 and Hcp2 Contribute to Edwardsiella ictaluri Pathogenesis. Front Vet Sci 2021; 8:681609. [PMID: 34150898 PMCID: PMC8207204 DOI: 10.3389/fvets.2021.681609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/07/2021] [Indexed: 01/22/2023] Open
Abstract
Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen causing enteric septicemia of catfish (ESC), a devastating disease resulting in significant economic losses in the U.S. catfish industry. Bacterial secretion systems are involved in many bacteria's virulence, and Type VI Secretion System (T6SS) is a critical apparatus utilized by several pathogenic Gram-negative bacteria. E. ictaluri strain 93-146 genome has a complete T6SS operon with 16 genes, but the roles of these genes are still not explored. In this research, we aimed to understand the roles of two hemolysin co-regulated family proteins, Hcp1 (EvpC) and Hcp2. To achieve this goal, single and double E. ictaluri mutants (EiΔevpC, EiΔhcp2, and EiΔevpCΔhcp2) were generated and characterized. Catfish peritoneal macrophages were able to kill EiΔhcp2 better than EiΔevpC, EiΔevpCΔhcp2, and E. ictaluri wild-type (EiWT). The attachment of EiΔhcp2 and EiΔevpCΔhcp2 to ovary cells significantly decreased compared to EiWT whereas the cell invasion rates of these mutants were the same as that of EiWT. Mutants exposed to normal catfish serum in vitro showed serum resistance. The fish challenges demonstrated that EiΔevpC and EiΔevpCΔhcp2 were attenuated completely and provided excellent protection against EiWT infection in catfish fingerlings. Interestingly, EiΔhcp2 caused higher mortality than that of EiWT in catfish fingerlings, and severe clinical signs were observed. Although fry were more susceptible to vaccination with EiΔevpC and EiΔevpCΔhcp2, their attenuation and protection were significantly higher compared to EiWT and sham groups, respectively. Taken together, our data indicated that evpC (hcp1) is involved in E. ictaluri virulence in catfish while hcp2 is involved in adhesion to epithelial cells and survival inside catfish macrophages.
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Affiliation(s)
- Safak Kalindamar
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Ordu University, Ordu, Turkey
| | - Hossam Abdelhamed
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Adef O Kordon
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Lesya M Pinchuk
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
| | - Attila Karsi
- Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, United States
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Howard SA, Furniss RCD, Bonini D, Amin H, Paracuellos P, Zlotkin D, Costa TRD, Levy A, Mavridou DAI, Filloux A. The Breadth and Molecular Basis of Hcp-Driven Type VI Secretion System Effector Delivery. mBio 2021; 12:e0026221. [PMID: 34061601 DOI: 10.1128/mBio.00262-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The type VI secretion system (T6SS) is a bacterial nanoscale weapon that delivers toxins into prey ranging from bacteria and fungi to animal hosts. The cytosolic contractile sheath of the system wraps around stacked hexameric rings of Hcp proteins, which form an inner tube. At the tip of this tube is a puncturing device comprising a trimeric VgrG topped by a monomeric PAAR protein. The number of toxins a single system delivers per firing event remains unknown, since effectors can be loaded on diverse sites of the T6SS apparatus, notably the inner tube and the puncturing device. Each VgrG or PAAR can bind one effector, and additional effector cargoes can be carried in the Hcp ring lumen. While many VgrG- and PAAR-bound toxins have been characterized, to date, very few Hcp-bound effectors are known. Here, we used 3 known Pseudomonas aeruginosa Hcp proteins (Hcp1 to -3), each of which associates with one of the three T6SSs in this organism (H1-T6SS, H2-T6SS, and H3-T6SS), to perform in vivo pulldown assays. We confirmed the known interactions of Hcp1 with Tse1 to -4, further copurified a Hcp1-Tse4 complex, and identified potential novel Hcp1-bound effectors. Moreover, we demonstrated that Hcp2 and Hcp3 can shuttle T6SS cargoes toxic to Escherichia coli. Finally, we used a Tse1-Bla chimera to probe the loading strategy for Hcp passengers and found that while large effectors can be loaded onto Hcp, the formed complex jams the system, abrogating T6SS function.
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Montenegro Benavides NA, Alvarez B A, Arrieta-Ortiz ML, Rodriguez-R LM, Botero D, Tabima JF, Castiblanco L, Trujillo C, Restrepo S, Bernal A. The type VI secretion system of Xanthomonas phaseoli pv. manihotis is involved in virulence and in vitro motility. BMC Microbiol 2021; 21:14. [PMID: 33407123 PMCID: PMC7788950 DOI: 10.1186/s12866-020-02066-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022] Open
Abstract
Background The type VI protein secretion system (T6SS) is important in diverse cellular processes in Gram-negative bacteria, including interactions with other bacteria and with eukaryotic hosts. In this study we analyze the evolution of the T6SS in the genus Xanthomonas and evaluate its importance of the T6SS for virulence and in vitro motility in Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of bacterial blight in cassava (Manihot esculenta). We delineate the organization of the T6SS gene clusters in Xanthomonas and then characterize proteins of this secretion system in Xpm strain CIO151. Results We describe the presence of three different clusters in the genus Xanthomonas that vary in their organization and degree of synteny between species. Using a gene knockout strategy, we also found that vgrG and hcp are required for maximal aggressiveness of Xpm on cassava plants while clpV is important for both motility and maximal aggressiveness. Conclusion We characterized the T6SS in 15 different strains in Xanthomonas and our phylogenetic analyses suggest that the T6SS might have been acquired by a very ancient event of horizontal gene transfer and maintained through evolution, hinting at their importance for the adaptation of Xanthomonas to their hosts. Finally, we demonstrated that the T6SS of Xpm is functional, and significantly contributes to virulence and motility. This is the first experimental study that demonstrates the role of the T6SS in the Xpm-cassava interaction and the T6SS organization in the genus Xanthomonas. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-020-02066-1.
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Affiliation(s)
| | - Alejandro Alvarez B
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | | | - Luis Miguel Rodriguez-R
- Department of Microbiology and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Tyrol, Austria
| | - David Botero
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Javier Felipe Tabima
- Botany and Plant Pathology Department, Oregon State University, Corvallis, OR, USA
| | - Luisa Castiblanco
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Cesar Trujillo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Adriana Bernal
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.
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Soria-Bustos J, Ares MA, Gómez-Aldapa CA, González-Y-Merchand JA, Girón JA, De la Cruz MA. Two Type VI Secretion Systems of Enterobacter cloacae Are Required for Bacterial Competition, Cell Adherence, and Intestinal Colonization. Front Microbiol 2020; 11:560488. [PMID: 33072020 PMCID: PMC7541819 DOI: 10.3389/fmicb.2020.560488] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 08/12/2020] [Indexed: 12/22/2022] Open
Abstract
Enterobacter cloacae has emerged as an opportunistic pathogen in healthcare-associated infections. Analysis of the genomic sequences of several E. cloacae strains revealed the presence of genes that code for expression of at least one type VI secretion system (T6SS). Here, we report that E. cloacae strain ATCC 13047 codes for two functional T6SS named T6SS-1 and T6SS-2. T6SS-1 and T6SS-2 were preferentially expressed in tryptic soy broth and tissue culture medium (DMEM), respectively. Mutants in T6SS-1-associated genes clpV1 and hcp1 significantly affected their ability of inter- and intra-bacterial killing indicating that T6SS-1 is required for bacterial competition. In addition, the Hcp effector protein was detected in supernatants of E. cloacae cultures and a functional T6SS-1 was required for the secretion of this protein. A clpV2 mutant was impaired in both biofilm formation and adherence to epithelial cells, supporting the notion that these phenotypes are T6SS-2 dependent. In vivo data strongly suggest that both T6SSs are required for intestinal colonization because single and double mutants in clpV1 and clpV2 genes were defective in gut colonization in mice. We conclude that the two T6SSs are involved in the pathogenesis scheme of E. cloacae with specialized functions in the interaction with other bacteria and with host cells.
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Affiliation(s)
- Jorge Soria-Bustos
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.,Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Carlos A Gómez-Aldapa
- Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km 4.5 Mineral de la Reforma, Hidalgo, Mexico
| | - Jorge A González-Y-Merchand
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Jorge A Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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11
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Song X, Hou M, Jiang H, Shen X, Xue M, Shao Y, Wang L, He Q, Zheng L, Tu J, Qi K. Hcp2a of type VI secretion system contributes to IL8 and IL1β expression of chicken tracheal epithelium by affecting APEC colonization. Res Vet Sci 2020; 132:279-284. [PMID: 32702515 DOI: 10.1016/j.rvsc.2020.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 07/03/2020] [Accepted: 07/13/2020] [Indexed: 01/06/2023]
Abstract
Avian pathogenic Escherichia coli (APEC) is an important pathogen that causes avian colibacillosis in poultry. APEC infection can lead to pathological changes in chicken trachea. The type VI secretion system (T6SS) of APEC contribute to the pathogenicity of APEC. However, whether T6SS plays a role in infection of the trachea remains unclear. We constructed mutant strain Δhcp2a by the Red recombination method system. The role of hcp2a (the structural secretion components and secretory protein of the T6SS) in the infection of trachea was investigated. The mutation strain displayed a significant increase in biofilm formation and a decrease in resistance to chicken serum. Moreover, RNA sequencing analyses showed that infection of chicken tracheal epithelium by the mutant strain Δhcp2a induced differential expression of genes. The result also showed that 14 genes (13 genes were downregulated) were enriched in cytokine-cytokine receptor interaction signalling pathway at 12 and 24 h post infection. The mutation Δhcp2a resulted in significant decreases in the bacterial loads in trachea at 6 and 12 h post infection. Real-time PCR analyses showed that the hcp2a mutation downregulated the expression of IL8 and IL1β at mRNA level in chicken tracheal epithelium. Our results indicate that mutation of hcp2a influenced genes expression of the cytokine-cytokine receptor interaction pathway by decreasing APEC colonization in the trachea.
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Affiliation(s)
- Xiangjun Song
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Manman Hou
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Huyan Jiang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Xiao Shen
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Mei Xue
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Ying Shao
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Lili Wang
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Qi He
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China
| | - Liming Zheng
- College of Basic Medicine, Anhui Medical University, Hefei 230032, PR China
| | - Jian Tu
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.
| | - Kezong Qi
- Anhui Province Key Laboratory of Veterinary Pathobiology and Disease Control, College of Animal Science and Technology, Anhui Agricultural University, Hefei 230036, PR China.
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12
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Zheng L, Wang S, Ling M, Lv Z, Lin S. Salmonella enteritidis Hcp distribute in the cytoplasm and regulate TNF signaling pathway in BHK-21 cells. 3 Biotech 2020; 10:301. [PMID: 32550118 PMCID: PMC7292845 DOI: 10.1007/s13205-020-02296-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023] Open
Abstract
Hemolysin-coregulated protein (Hcp) of Salmonella enteritidis is known to be a structural and effector protein of the T6SS, but little is known about the role of Hcp in host cells. In this study, Hcp was expressed by plasmid pEGFP-N1-hcp in BHK-21 cells and the results showed that the subcellular localization of Hcp was predominantly in the cytoplasm of BHK-21 cells. When Hcp was over-expressed by transfecting plasmid pCI-neo-hcp in BHK-21 cells and mRNA sequencing was performed to analyze differentially expressed genes, the results showed a change in the expression levels of 307 mRNAs (fold change > 2, and p < 0.01). Amongst these, 125 mRNAs were up-regulated and 182 mRNAs were down-regulated. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that differentially expressed genes were enriched in tumor necrosis factor (TNF) signaling pathway, IL-17 signaling pathway, and cytokine-cytokine receptor interaction. Subsequently, we selected differentially expressed genes of TNF signaling pathway and verified the changes by real-time PCR. The results were consistent with the trend observed for the sequencing results. In conclusion, we demonstrated that Hcp of Salmonella enteritidis caused the change of mRNAs expression of TNF signaling pathway in the cytoplasm of BHK-21 cells.
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Affiliation(s)
- Liming Zheng
- Anhui Medical University, Hefei, 230032 People’s Republic of China
| | - Shenghua Wang
- Anhui Medical University, Hefei, 230032 People’s Republic of China
| | - Mengyu Ling
- Anhui Medical University, Hefei, 230032 People’s Republic of China
| | - Zhengmei Lv
- Anhui Medical University, Hefei, 230032 People’s Republic of China
| | - Shuai Lin
- Anhui Medical University, Hefei, 230032 People’s Republic of China
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13
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Abstract
Significance: S-nitrosylation, the post-translational modification by nitric oxide (NO) to form S-nitrosothiols (SNOs), regulates diverse aspects of cellular function, and aberrant S-nitrosylation (nitrosative stress) is implicated in disease, from neurodegeneration to cancer. Essential roles for S-nitrosylation have been demonstrated in microbes, plants, and animals; notably, bacteria have often served as model systems for elucidation of general principles. Recent Advances: Recent conceptual advances include the idea of a molecular code through which proteins sense and differentiate S-nitrosothiol (SNO) from alternative oxidative modifications, providing the basis for specificity in SNO signaling. In Escherichia coli, S-nitrosylation relies on an enzymatic cascade that regulates, and is regulated by, the transcription factor OxyR under anaerobic conditions. S-nitrosylated OxyR activates an anaerobic regulon of >100 genes that encode for enzymes that both mediate S-nitrosylation and protect against nitrosative stress. Critical Issues: Mitochondria originated from endosymbiotic bacteria and generate NO under hypoxic conditions, analogous to conditions in E. coli. Nitrosative stress in mitochondria has been implicated in Alzheimer's and Parkinson's disease, among others. Many proteins that are S-nitrosylated in mitochondria are also S-nitrosylated in E. coli. Insights into enzymatic regulation of S-nitrosylation in E. coli may inform the identification of disease-relevant regulatory machinery in mammalian systems. Future Directions: Using E. coli as a model system, in-depth analysis of the anaerobic response controlled by OxyR may lead to the identification of enzymatic mechanisms regulating S-nitrosylation in particular, and hypoxic signaling more generally, providing novel insights into analogous mechanisms in mammalian cells and within dysfunctional mitochondria that characterize neurodegenerative diseases.
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Affiliation(s)
- Divya Seth
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Alfred Hausladen
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio
| | - Jonathan S Stamler
- Institute for Transformative Molecular Medicine and Department of Medicine, Case Western Reserve University School of Medicine and University Hospitals Cleveland Medical Center, Cleveland, Ohio.,Harrington Discovery Institute, University Hospitals Cleveland Medical Center, Cleveland, Ohio
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14
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Belvin BR, Gui Q, Hutcherson JA, Lewis JP. The Porphyromonas gingivalis Hybrid Cluster Protein Hcp Is Required for Growth with Nitrite and Survival with Host Cells. Infect Immun 2019; 87:e00572-18. [PMID: 30670550 DOI: 10.1128/IAI.00572-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 01/11/2019] [Indexed: 12/13/2022] Open
Abstract
Although the periodontal pathogen Porphyromonas gingivalis must withstand high levels of nitrosative stress while in the oral cavity, the mechanisms of nitrosative stress defense are not well understood in this organism. Previously we showed that the transcriptional regulator HcpR plays a significant role in defense, and here we further defined its regulon. Our study shows that hcp (PG0893), a putative nitric oxide (NO) reductase, is the only gene significantly upregulated in response to nitrite (NO2) and that this regulation is dependent on HcpR. An isogenic mutant deficient in hcp is not able to grow with 200 μM nitrite, demonstrating that the sensitivity of the HcpR mutant is mediated through Hcp. We further define the molecular mechanisms of HcpR interaction with the hcp promoter through mutational analysis of the inverted repeat present within the promoter. Although other putative nitrosative stress protection mechanisms present on the nrfAH operon are also found in the P. gingivalis genome, we show that their gene products play no role in growth of the bacterium with nitrite. As growth of the hcp-deficient strain was also significantly diminished in the presence of a nitric oxide-producing compound, S-nitrosoglutathione (GSNO), Hcp appears to be the primary means by which P. gingivalis responds to NO2 --based stress. Finally, we show that Hcp is required for survival with host cells but that loss of Hcp has no effect on association and entry of P. gingivalis into human oral keratinocytes.
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15
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Tekedar HC, Abdelhamed H, Kumru S, Blom J, Karsi A, Lawrence ML. Comparative Genomics of Aeromonas hydrophila Secretion Systems and Mutational Analysis of hcp1 and vgrG1 Genes From T6SS. Front Microbiol 2019; 9:3216. [PMID: 30687246 PMCID: PMC6333679 DOI: 10.3389/fmicb.2018.03216] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022] Open
Abstract
Virulent Aeromonas hydrophila causes severe motile Aeromonas septicemia in warmwater fishes. In recent years, channel catfish farming in the U.S.A. and carp farming in China have been affected by virulent A. hydrophila, and genome comparisons revealed that these virulent A. hydrophila strains belong to the same clonal group. Bacterial secretion systems are often important virulence factors; in the current study, we investigated whether secretion systems contribute to the virulent phenotype of these strains. Thus, we conducted comparative secretion system analysis using 55 A. hydrophila genomes, including virulent A. hydrophila strains from U.S.A. and China. Interestingly, tight adherence (TaD) system is consistently encoded in all the vAh strains. The majority of U.S.A. isolates do not possess a complete type VI secretion system, but three core elements [tssD (hcp), tssH, and tssI (vgrG)] are encoded. On the other hand, Chinese isolates have a complete type VI secretion system operon. None of the virulent A. hydrophila isolates have a type III secretion system. Deletion of two genes encoding type VI secretion system proteins (hcp1 and vgrG1) from virulent A. hydrophila isolate ML09-119 reduced virulence 2.24-fold in catfish fingerlings compared to the parent strain ML09-119. By determining the distribution of genes encoding secretion systems in A. hydrophila strains, our study clarifies which systems may contribute to core A. hydrophila functions and which may contribute to more specialized adaptations such as virulence. Our study also clarifies the role of type VI secretion system in A. hydrophila virulence.
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Affiliation(s)
- Hasan C Tekedar
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Hossam Abdelhamed
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Salih Kumru
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Attila Karsi
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
| | - Mark L Lawrence
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
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16
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Paredes-Amaya CC, Valdés-García G, Juárez-González VR, Rudiño-Piñera E, Bustamante VH. The Hcp-like protein HilE inhibits homodimerization and DNA binding of the virulence-associated transcriptional regulator HilD in Salmonella. J Biol Chem 2018. [PMID: 29535187 DOI: 10.1074/jbc.ra117.001421] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
HilD is an AraC-like transcriptional regulator that plays a central role in Salmonella virulence. HilD controls the expression of the genes within the Salmonella pathogenicity island 1 (SPI-1) and of several genes located outside SPI-1, which are mainly required for Salmonella invasion of host cells. The expression, amount, and activity of HilD are tightly controlled by the activities of several factors. The HilE protein represses the expression of the SPI-1 genes through its interaction with HilD; however, the mechanism by which HilE affects HilD is unknown. In this study, we used genetic and biochemical assays revealing how HilE controls the transcriptional activity of HilD. We found that HilD needs to assemble in homodimers to induce expression of its target genes. Our results further indicated that HilE individually interacts with each the central and the C-terminal HilD regions, mediating dimerization and DNA binding, respectively. We also observed that these interactions consistently inhibit HilD dimerization and DNA binding. Interestingly, a computational analysis revealed that HilE shares sequence and structural similarities with Hcp proteins, which act as structural components of type 6 secretion systems in Gram-negative bacteria. In conclusion, our results uncover the molecular mechanism by which the Hcp-like protein HilE controls dimerization and DNA binding of the virulence-promoting transcriptional regulator HilD. Our findings may indicate that HilE's activity represents a functional adaptation during the evolution of Salmonella pathogenicity.
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Affiliation(s)
| | - Gilberto Valdés-García
- Molecular Medicine and Bioprocesses, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Víctor R Juárez-González
- Molecular Medicine and Bioprocesses, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Enrique Rudiño-Piñera
- Molecular Medicine and Bioprocesses, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
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17
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Rashid M, Caine V, Newton AS, Goez HR. Healthcare professionals' perspective on the delivery of care to children with Acquired Brain Injury (ABI) and communication with their parents. J Pediatr Rehabil Med 2018; 11:125-131. [PMID: 30010150 DOI: 10.3233/prm-170512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
PURPOSE The purpose of this study was to understand healthcare providers' perspective and responsivity to families' needs in rehabilitative care delivery for children with Acquired Brain Injury (ABI). METHODS Three focus group sessions were conducted to explore and understand multidisciplinary healthcare professionals' (Hcps) perspectives about the care they deliver to parents of children with ABI. Convenience sampling was used to recruit healthcare providers (total sample size = 15) from a large rehabiliation centre of an urban setting in western Canada. Data was collected through semi-structured interviews and analysed thematically. RESULTS Findings from this study revealed Hcps' perspectives on their day-to-day delivery of care and furthered our understanding of their challenges. It also increased our awareness about the rewards that Hcp gain as a result of their work. Five main themes emerged: (1) Getting back to normal; (2) Hsps' roles and perception; (3) Challenges in practices; (4) Practice rewards; (5) a focus on solutions/ideas for better healthcare delivery. CONCLUSION Hcps' perspectives on their day-to-day delivery of care to families who have a child with ABI enhance our knowledge about the existing challenges and complexities. Findings from this study have significant implication for rehabilitation services in making rehabilitation goals more achievable for families of children with ABI.
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Affiliation(s)
- Marghalara Rashid
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Vera Caine
- Faculty of Nursing, University of Alberta, Edmonton, AB, Canada
| | - Amanda S Newton
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Helly R Goez
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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18
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Bleves S. Don't judge a book by its cover: The Hcps are not only structural components of the T6SS machinery. Virulence 2017; 8:1053-1054. [PMID: 28277899 DOI: 10.1080/21505594.2017.1295908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Sophie Bleves
- a Aix-Marseille Univ, CNRS, LISM UMR7255, IMM (Institut de Microbiologie de la Méditerranée) , Marseille , France
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19
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Masum MMI, Yang Y, Li B, Olaitan OS, Chen J, Zhang Y, Fang Y, Qiu W, Wang Y, Sun G. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2. Int J Mol Sci 2017; 18:ijms18102024. [PMID: 28934168 PMCID: PMC5666706 DOI: 10.3390/ijms18102024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/09/2017] [Accepted: 09/19/2017] [Indexed: 12/17/2022] Open
Abstract
The Type VI secretion system (T6SS) is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2) and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations ΔpppA, ΔclpB, Δhcp, ΔdotU, ΔicmF, ΔimpJ, and ΔimpM caused similar virulence characteristics as RS-2. Moreover, the mutant ΔpppA, ΔclpB, ΔicmF, ΔimpJ and ΔimpM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants ΔpppA, ΔclpB, ΔicmF and Δhcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.
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Affiliation(s)
- Md Mahidul Islam Masum
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
- Department of Plant Pathology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh.
| | - Yingzi Yang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Bin Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Ogunyemi Solabomi Olaitan
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Jie Chen
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yang Zhang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yushi Fang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Wen Qiu
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
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20
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Huang Y, Du P, Zhao M, Liu W, Du Y, Diao B, Li J, Kan B, Liang W. Functional Characterization and Conditional Regulation of the Type VI Secretion System in Vibrio fluvialis. Front Microbiol 2017; 8:528. [PMID: 28424671 PMCID: PMC5371669 DOI: 10.3389/fmicb.2017.00528] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/14/2017] [Indexed: 01/22/2023] Open
Abstract
Vibrio fluvialis is an emerging foodborne pathogen of increasing public health concern. The mechanism(s) that contribute to the bacterial survival and disease are still poorly understood. In other bacterial species, type VI secretion systems (T6SSs) are known to contribute to bacterial pathogenicity by exerting toxic effects on host cells or competing bacterial species. In this study, we characterized the genetic organization and prevalence of two T6SS gene clusters (VflT6SS1 and VflT6SS2) in V. fluvialis. VflT6SS2 harbors three “orphan” hcp-vgrG modules and was more prevalent than VflT6SS1 in our isolates. We showed that VflT6SS2 is functionally active under low (25°C) and warm (30°C) temperatures by detecting the secretion of a T6SS substrate, Hcp. This finding suggests that VflT6SS2 may play an important role in the survival of the bacterium in the aquatic environment. The secretion of Hcp is growth phase-dependent and occurs in a narrow range of the growth phase (OD600 from 1.0 to 2.0). Osmolarity also regulates the function of VflT6SS2, as evidenced by our finding that increasing salinity (from 170 to 855 mM of NaCl) and exposure to high osmolarity KCl, sucrose, trehalose, or mannitol (equivalent to 340 mM of NaCl) induced significant secretion of Hcp under growth at 30°C. Furthermore, we found that although VflT6SS2 was inactive at a higher temperature (37°C), it became activated at this temperature if higher salinity conditions were present (from 513 to 855 mM of NaCl), indicating that it may be able to function under certain conditions in the infected host. Finally, we showed that the functional expression of VflT6SS2 is associated with anti-bacterial activity. This activity is Hcp-dependent and requires vasH, a transcriptional regulator of T6SS. In sum, our study demonstrates that VflT6SS2 provides V. fluvialis with an enhanced competitive fitness in the marine environment, and its activity is regulated by environmental signals, such as temperature and osmolarity.
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Affiliation(s)
- Yuanming Huang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Pengcheng Du
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical UniversityBeijing, China
| | - Meng Zhao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Wei Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Yu Du
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Baowei Diao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Jie Li
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China
| | - Biao Kan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Weili Liang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China.,Collaborative Innovation Centre for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
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21
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Ma J, Pan Z, Huang J, Sun M, Lu C, Yao H. The Hcp proteins fused with diverse extended-toxin domains represent a novel pattern of antibacterial effectors in type VI secretion systems. Virulence 2017; 8:1189-1202. [PMID: 28060574 DOI: 10.1080/21505594.2017.1279374] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The type VI secretion system (T6SS) is a widespread molecular weapon deployed by many bacterial species to target eukaryotic host cells or rival bacteria. Using a dynamic injection mechanism, diverse effectors can be delivered by T6SS directly into recipient cells. Here, we report a new family of T6SS effectors encoded by extended Hcps carrying diverse toxin domains. Bioinformatic analyses revealed that these Hcps with C-terminal extension toxins, designated as Hcp-ET, exist widely in the Enterobacteriaceae. To verify our findings, Hcp-ET1 was tested for its antibacterial effect, and showed effective inhibition of target cell growth via the predicted HNH-DNase activity by T6SS-dependent delivery. Further studies showed that Hcp-ET2 mediated interbacterial antagonism via a Tle1 phospholipase (encoded by DUF2235 domain) activity. Notably, comprehensive analyses of protein homology and genomic neighborhoods revealed that Hcp-ET3-4 is fused with 2 toxin domains (Pyocin S3 and Colicin-DNase) C-terminally, and its encoding gene is followed 3 duplications of the cognate immunity genes. However, some bacteria encode a separated hcp-et3 and an orphan et4 (et4O1) genes caused by a termination-codon mutation in the fusion region between Pyocin S3 and Colicin-DNase encoding fragments. Our results demonstrated that both of these toxins had antibacterial effects. Further, all duplications of the cognate immunity protein contributed to neutralize the DNase toxicity of Pyocin S3 and Colicin, which has not been reported previously. In conclusion, we propose that Hcp-ET proteins are polymorphic T6SS effectors, and thus present a novel encoding pattern of T6SS effectors.
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Affiliation(s)
- Jiale Ma
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
| | - Zihao Pan
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
| | - Jinhu Huang
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
| | - Min Sun
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
| | - Chengping Lu
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
| | - Huochun Yao
- a Department of Veterinary Microbiology and Immunology, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing , China.,b Key Lab of Animal Bacteriology, Ministry of Agriculture , Nanjing , China
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22
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Weber BS, Ly PM, Feldman MF. Screening for Secretion of the Type VI Secretion System Protein Hcp by Enzyme-Linked Immunosorbent Assay and Colony Blot. Methods Mol Biol 2017; 1615:465-472. [PMID: 28667630 DOI: 10.1007/978-1-4939-7033-9_32] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The bacterial type VI secretion system (T6SS) is a secretory apparatus encoded by many Gram-negative bacteria. The T6SS facilitates the secretion and injection of toxic effector proteins into host cells, providing a competitive advantage to bacteria encoding this machinery. The activity of the T6SS can be monitored by probing for the conserved tubule component Hcp, which is secreted to the supernatants by the T6SS. Detection of Hcp in culture supernatants is indicative of an active T6SS, but this secretion system is often tightly regulated or inactive under laboratory conditions and different bacterial strains display differing Hcp secretion phenotypes. Herein, we describe an enzyme-linked immunosorbent assay (ELISA) and colony blot methods to facilitate large-scale screening of isolates for Hcp secretion and, thus, T6SS activity.
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Affiliation(s)
- Brent S Weber
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Pek Man Ly
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Mario F Feldman
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA.
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23
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Dong Q, Luo J, Qiu W, Cai L, Anjum SI, Li B, Hou M, Xie G, Sun G. Inhibitory Effect of Camptothecin against Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae RS-2. Molecules 2016; 21:molecules21080978. [PMID: 27472315 PMCID: PMC6274382 DOI: 10.3390/molecules21080978] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 12/28/2022] Open
Abstract
Camptothecin (CPT) has anticancer, antiviral, and antifungal properties. However, there is a dearth of information about antibacterial activity of CPT. Therefore, in this study, we investigated the inhibitory effect of CPT on Acidovorax avenae subsp. avenae strain RS-2, the pathogen of rice bacterial brown stripe, by measuring cell growth, DNA damage, cell membrane integrity, the expression of secretion systems, and topoisomerase-related genes, as well as the secretion of effector protein Hcp. Results indicated that CPT solutions at 0.05, 0.25, and 0.50 mg/mL inhibited the growth of strain RS-2 in vitro, while the inhibitory efficiency increased with an increase in CPT concentration, pH, and incubation time. Furthermore, CPT treatment affected bacterial growth and replication by causing membrane damage, which was evidenced by transmission electron microscopic observation and live/dead cell staining. In addition, quantitative real-time PCR analysis indicated that CPT treatment caused differential expression of eight secretion system-related genes and one topoisomerase-related gene, while the up-regulated expression of hcp could be justified by the increased secretion of Hcp based on the ELISA test. Overall, this study indicated that CPT has the potential to control the bacterial brown stripe pathogen of rice.
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Affiliation(s)
- Qiaolin Dong
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ju Luo
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China.
| | - Wen Qiu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China.
| | - Li Cai
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Syed Ishtiaq Anjum
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China.
- Department of Zoology Kohat University of Science and Technology Kohat, Khyber Pakhtunkhwa 26000, Pakistan.
| | - Bin Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China.
| | - Mingsheng Hou
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guanlin Xie
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China.
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
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24
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Zoued A, Brunet YR, Durand E, Aschtgen MS, Logger L, Douzi B, Journet L, Cambillau C, Cascales E. Architecture and assembly of the Type VI secretion system. Biochim Biophys Acta 2014; 1843:1664-73. [PMID: 24681160 DOI: 10.1016/j.bbamcr.2014.03.018] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/31/2022]
Abstract
The Type VI secretion system (T6SS) delivers protein effectors to diverse cell types including prokaryotic and eukaryotic cells, therefore it participates in inter-bacterial competition and pathogenesis. The T6SS is constituted of an envelope-spanning complex anchoring a cytoplasmic tubular edifice. This tubular structure is evolutionarily, functionally and structurally related to the tail of contractile phages. It is composed of an inner tube tipped by a spike complex, and engulfed within a sheath-like structure. This structure assembles onto a platform called "baseplate" that is connected to the membrane sub-complex. The T6SS functions as a nano-crossbow: upon contraction of the sheath, the inner tube is propelled towards the target cell, allowing effector delivery. This review focuses on the architecture and biogenesis of this fascinating secretion machine, highlighting recent advances regarding the assembly of the membrane or tail complexes. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Abdelrahim Zoued
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Yannick R Brunet
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Eric Durand
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Marie-Stéphanie Aschtgen
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Laureen Logger
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Badreddine Douzi
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Laure Journet
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Eric Cascales
- Laboratoire d'Ingeniérie des Systèmes Macromoléculaires, CNRS, Aix-Marseille Université, UMR 7255, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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25
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Zoued A, Durand E, Bebeacua C, Brunet YR, Douzi B, Cambillau C, Cascales E, Journet L. TssK is a trimeric cytoplasmic protein interacting with components of both phage-like and membrane anchoring complexes of the type VI secretion system. J Biol Chem 2013; 288:27031-27041. [PMID: 23921384 PMCID: PMC3779704 DOI: 10.1074/jbc.m113.499772] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 08/05/2013] [Indexed: 11/06/2022] Open
Abstract
The Type VI secretion system (T6SS) is a macromolecular machine that mediates bacteria-host or bacteria-bacteria interactions. The T6SS core apparatus assembles from 13 proteins that form two sub-assemblies: a phage-like complex and a trans-envelope complex. The Hcp, VgrG, TssE, and TssB/C subunits are structurally and functionally related to components of the tail of contractile bacteriophages. This phage-like structure is thought to be anchored to the membrane by a trans-envelope complex composed of the TssJ, TssL, and TssM proteins. However, how the two sub-complexes are connected remains unknown. Here we identify TssK, a protein that establishes contacts with the two T6SS sub-complexes through direct interactions with TssL, Hcp, and TssC. TssK is a cytoplasmic protein assembling trimers that display a three-armed shape, as revealed by TEM and SAXS analyses. Fluorescence microscopy experiments further demonstrate the requirement of TssK for sheath assembly. Our results suggest a central role for TssK by linking both complexes during T6SS assembly.
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Affiliation(s)
- Abdelrahim Zoued
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, UMR 7255, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Eric Durand
- Architecture et Fonction des Macromolécules Biologiques, Campus de Luminy, Case 932, Aix-Marseille Université, CNRS UMR 6098, 13288 Marseille Cedex 09, France
| | - Cecilia Bebeacua
- Architecture et Fonction des Macromolécules Biologiques, Campus de Luminy, Case 932, Aix-Marseille Université, CNRS UMR 6098, 13288 Marseille Cedex 09, France
| | - Yannick R Brunet
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, UMR 7255, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Badreddine Douzi
- Architecture et Fonction des Macromolécules Biologiques, Campus de Luminy, Case 932, Aix-Marseille Université, CNRS UMR 6098, 13288 Marseille Cedex 09, France
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, Campus de Luminy, Case 932, Aix-Marseille Université, CNRS UMR 6098, 13288 Marseille Cedex 09, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, UMR 7255, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Laure Journet
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, UMR 7255, Aix-Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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26
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Aschtgen MS, Zoued A, Lloubès R, Journet L, Cascales E. The C-tail anchored TssL subunit, an essential protein of the enteroaggregative Escherichia coli Sci-1 Type VI secretion system, is inserted by YidC. Microbiologyopen 2012; 1:71-82. [PMID: 22950014 PMCID: PMC3426401 DOI: 10.1002/mbo3.9] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 01/09/2023] Open
Abstract
Type VI secretion systems (T6SS) are macromolecular complexes present in Gram-negative bacteria. T6SS are structurally similar to the bacteriophage cell-puncturing device and have been shown to mediate bacteria–host or bacteria–bacteria interactions. T6SS assemble from 13 to 20 proteins. In enteroaggregative Escherichia coli (EAEC), one of the subassemblies is composed of four proteins that form a trans-envelope complex: the TssJ outer membrane lipoprotein, the peptidoglycan-anchored inner membrane TagL protein, and two putative inner membrane proteins, TssL and TssM. In this study, we characterized the TssL protein of the EAEC Sci-1 T6SS in terms of localization, topology, and function. TssL is a critical component of the T6SS, anchored to the inner membrane through a single transmembrane segment located at the extreme C-terminus of the protein. We further show that this transmembrane segment is essential for the function of the protein and its proper insertion in the inner membrane is dependent upon YidC and modulated by the Hsp70 homologue DnaK.
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Affiliation(s)
- Marie-Stéphanie Aschtgen
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université CNRS - UMR 7255, 31 chemin Joseph Aiguier, 13402, Marseille Cedex 20, France
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