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Amin H, Ilangovan A, Costa TRD. Architecture of the outer-membrane core complex from a conjugative type IV secretion system. Nat Commun 2021; 12:6834. [PMID: 34824240 PMCID: PMC8617172 DOI: 10.1038/s41467-021-27178-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022] Open
Abstract
Conjugation is one of the most important processes that bacteria utilize to spread antibiotic resistance genes among bacterial populations. Interbacterial DNA transfer requires a large double membrane-spanning nanomachine called the type 4 secretion system (T4SS) made up of the inner-membrane complex (IMC), the outer-membrane core complex (OMCC) and the conjugative pilus. The iconic F plasmid-encoded T4SS has been central in understanding conjugation for several decades, however atomic details of its structure are not known. Here, we report the structure of a complete conjugative OMCC encoded by the pED208 plasmid from E. coli, solved by cryo-electron microscopy at 3.3 Å resolution. This 2.1 MDa complex has a unique arrangement with two radial concentric rings, each having a different symmetry eventually contributing to remarkable differences in protein stoichiometry and flexibility in comparison to other OMCCs. Our structure suggests that F-OMCC is a highly dynamic complex, with implications for pilus extension and retraction during conjugation.
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Affiliation(s)
- Himani Amin
- grid.7445.20000 0001 2113 8111MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ UK
| | - Aravindan Ilangovan
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
| | - Tiago R. D. Costa
- grid.7445.20000 0001 2113 8111MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ UK
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Wang H, Qi H, Gong S, Huang Z, Meng C, Zhang Y, Chen X, Jiao X. Fe 3O 4 composited with MoS 2 blocks horizontal gene transfer. Colloids Surf B Biointerfaces 2020; 185:110569. [PMID: 31629970 DOI: 10.1016/j.colsurfb.2019.110569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/13/2019] [Accepted: 10/06/2019] [Indexed: 11/25/2022]
Abstract
In this study, we found that Fe3O4 promoted horizontal gene transfer (HGT), but when Fe3O4 was composited with MoS2, the Fe3O4@MoS2 nanocomposite interacting with bacteria significantly blocked the HGT in the conjugation system. qPCR was used to analyze the expression of genes belonging to the chromosome and plasmid in the conjugation system. Results demonstrated that Fe3O4@MoS2 inhibited conjugation by promoting the expression of the global regulatory gene (trbA) and inhibiting the expression of conjugative transfer genes involved in mating pair formation (traF, trbB), DNA replication (trfA), and porins (outer membrane protein (omp) A and ompC). All of these genes are related to the permeability of the cell membrane, except for trfA. The results showed that Fe3O4@MoS2 interacted with bacteria to decrease their permeability against exogenous DNA. MoS2 may play an essential role in the HGT-inhibiting activity of Fe3O4@MoS2. This study highlights the diverse biological properties of nano-materials and provides clues for nano-scientists to develop environmentally friendly materials.
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Affiliation(s)
- Honggui Wang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University (26116120), Yangzhou, Jiangsu, 225009, PR China; School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China
| | - Huachen Qi
- School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China
| | - Shujun Gong
- School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China
| | - Zhihai Huang
- School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China
| | - Chuang Meng
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University (26116120), Yangzhou, Jiangsu, 225009, PR China
| | - Ya Zhang
- School of Environmental Science and Engineering, Yangzhou University, 225127, Yangzhou, Jiangsu, PR China.
| | - Xiang Chen
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University (26116120), Yangzhou, Jiangsu, 225009, PR China
| | - Xin'an Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, 225009, PR China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University (26116120), Yangzhou, Jiangsu, 225009, PR China.
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Johansson A, Claesson R, Höglund Åberg C, Haubek D, Lindholm M, Jasim S, Oscarsson J. Genetic Profiling of Aggregatibacter actinomycetemcomitans Serotype B Isolated from Periodontitis Patients Living in Sweden. Pathogens 2019; 8:pathogens8030153. [PMID: 31533208 PMCID: PMC6789814 DOI: 10.3390/pathogens8030153] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/10/2019] [Accepted: 09/15/2019] [Indexed: 02/06/2023] Open
Abstract
The bacterium Aggregatibacter actinomycetemcomitans is associated with aggressive forms of periodontitis and with systemic diseases, such as endocarditis. By assessing a Ghanaian longitudinal adolescent cohort, we earlier recognized the cagE gene as a possible diagnostic marker for a subgroup of JP2 and non-JP2 genotype serotype b A. actinomycetemcomitans strains, associated with high leukotoxicity as determined in a semi-quantitative cell assay. This group of A. actinomycetemcomitans is associated with the progression of attachment loss. In the present work, we used conventional polymerase chain reaction (PCR) and quantitative PCR to perform the cagE genotyping of our collection of 116 selected serotype b A. actinomycetemcomitans strains, collected over a period of 15 years from periodontitis patients living in Sweden. The A. actinomycetemcomitans strains carrying cagE (referred to as cagE+; n = 49) were compared to the cagE-negative strains (n = 67), present at larger proportions in the subgingival plaque samples, and were also much more prevalent in the young (≤35 years) compared to in the old (>35 years) group of patients. Our present results underline the potential use of cagE genotyping in the risk assessment of the development of periodontal attachment loss in Swedish adolescents.
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Affiliation(s)
- Anders Johansson
- Division of Molecular Periodontology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden
| | - Rolf Claesson
- Division of Oral Microbiology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden
| | - Carola Höglund Åberg
- Division of Molecular Periodontology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden
| | - Dorte Haubek
- Section for Pediatric Dentistry, Department of Dentistry and Oral Health, Aarhus University, 8000 Aarhus, Denmark
| | - Mark Lindholm
- Division of Oral Microbiology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden
| | - Sarah Jasim
- Division of Oral Microbiology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden
| | - Jan Oscarsson
- Division of Oral Microbiology, Department of Odontology, Umeå University, 907 00 Umeå, Sweden.
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Spread and Persistence of Virulence and Antibiotic Resistance Genes: A Ride on the F Plasmid Conjugation Module. EcoSal Plus 2019; 8. [PMID: 30022749 DOI: 10.1128/ecosalplus.esp-0003-2018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The F plasmid or F-factor is a large, 100-kbp, circular conjugative plasmid of Escherichia coli and was originally described as a vector for horizontal gene transfer and gene recombination in the late 1940s. Since then, F and related F-like plasmids have served as role models for bacterial conjugation. At present, more than 200 different F-like plasmids with highly related DNA transfer genes, including those for the assembly of a type IV secretion apparatus, are completely sequenced. They belong to the phylogenetically related MOBF12A group. F-like plasmids are present in enterobacterial hosts isolated from clinical as well as environmental samples all over the world. As conjugative plasmids, F-like plasmids carry genetic modules enabling plasmid replication, stable maintenance, and DNA transfer. In this plasmid backbone of approximately 60 kbp, the DNA transfer genes occupy the largest and mostly conserved part. Subgroups of MOBF12A plasmids can be defined based on the similarity of TraJ, a protein required for DNA transfer gene expression. In addition, F-like plasmids harbor accessory cargo genes, frequently embedded within transposons and/or integrons, which harness their host bacteria with antibiotic resistance and virulence genes, causing increasingly severe problems for the treatment of infectious diseases. Here, I focus on key genetic elements and their encoded proteins present on the F-factor and other typical F-like plasmids belonging to the MOBF12A group of conjugative plasmids.
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Schultz LG, Tasic L, Fattori J. Chaperone-Assisted Secretion in Bacteria: Protein and DNA Transport via Cell Membranes. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180820154821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Bacteria use an impressive arsenal of secretion systems (1-7) to infect their host cells by exporting
proteins, DNA and DNA-protein complexes via cell membranes. They use chaperone-usher
pathways for host colonization as well. To be targeted for transportation across one (Gram-positive) or
two membranes (Gram-negative), clients must be selected, guided and unfolded to pass through type 3
(T3SS) or type 4 (T4SS) secretion systems. For these processes, bacteria count on secretory chaperones
that guide macromolecular transport via membranes. Moreover, if we know how these processes
occur, we might be able to stop them and avoid bacterial infections. Thus, structural and functional
characterizations of secretory chaperones become interesting, as these proteins are the perfect targets
for blocking bacteria action. Therefore, this review focuses on a story of known mechanisms of chaperone-
secretion assisted transport with special attention on virulence proteins and DNA transport in
bacteria.
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Affiliation(s)
- Lilian Goulart Schultz
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
| | - Ljubica Tasic
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
| | - Juliana Fattori
- Chemical Biology Laboratory, Organic Chemistry Department, Institute of Chemistry, University of Campinas, P.O. Box 6154, Campinas, 13083-970, SP, Brazil
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Mancilla M, Saavedra J, Grandón M, Tapia E, Navas E, Grothusen H, Bustos P. The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon, Salmo salar. JOURNAL OF FISH DISEASES 2018; 41:625-634. [PMID: 29251345 DOI: 10.1111/jfd.12762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/06/2017] [Accepted: 11/10/2017] [Indexed: 06/07/2023]
Abstract
Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS-ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM-90-like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE-214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis' virulence relies on an intact T4SS.
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Affiliation(s)
- M Mancilla
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - J Saavedra
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - M Grandón
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - E Tapia
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - E Navas
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - H Grothusen
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
| | - P Bustos
- Laboratorio de Diagnóstico y Biotecnología, ADL Diagnostic Chile, Puerto Montt, Chile
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Arabidopsis RETICULON-LIKE3 (RTNLB3) and RTNLB8 Participate in Agrobacterium-Mediated Plant Transformation. Int J Mol Sci 2018; 19:ijms19020638. [PMID: 29495267 PMCID: PMC5855860 DOI: 10.3390/ijms19020638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/05/2022] Open
Abstract
Agrobacterium tumefaciens can genetically transform various eukaryotic cells because of the presence of a resident tumor-inducing (Ti) plasmid. During infection, a defined region of the Ti plasmid, transfer DNA (T-DNA), is transferred from bacteria into plant cells and causes plant cells to abnormally synthesize auxin and cytokinin, which results in crown gall disease. T-DNA and several virulence (Vir) proteins are secreted through a type IV secretion system (T4SS) composed of T-pilus and a transmembrane protein complex. Three members of Arabidopsis reticulon-like B (RTNLB) proteins, RTNLB1, 2, and 4, interact with VirB2, the major component of T-pilus. Here, we have identified that other RTNLB proteins, RTNLB3 and 8, interact with VirB2 in vitro. Root-based A. tumefaciens transformation assays with Arabidopsis rtnlb3, or rtnlb5-10 single mutants showed that the rtnlb8 mutant was resistant to A. tumefaciens infection. In addition, rtnlb3 and rtnlb8 mutants showed reduced transient transformation efficiency in seedlings. RTNLB3- or 8 overexpression transgenic plants showed increased susceptibility to A. tumefaciens and Pseudomonas syringae infection. RTNLB1-4 and 8 transcript levels differed in roots, rosette leaves, cauline leaves, inflorescence, flowers, and siliques of wild-type plants. Taken together, RTNLB3 and 8 may participate in A. tumefaciens infection but may have different roles in plants.
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Liu CC, Chen CH, Tang CY, Chen KH, Chen ZF, Chang SH, Tsai CY, Liou ML. Prevalence and comparative analysis of the type IV secretion system in Aggregatibacter actinomycetemcomitan. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2017; 51:278-285. [PMID: 28711435 DOI: 10.1016/j.jmii.2016.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/11/2016] [Accepted: 12/13/2016] [Indexed: 11/25/2022]
Abstract
BACKGROUD/PURPOSE Aggregatibacter actinomycetemcomitans has emerged as one of the aetiological agents in periodontal disease. Although Type IV secretion systems (T4SSs) are widely distributed in many bacteria, the genetic features and distribution of T4SSs in A. actinomycetemcomitans remain unclear. In this study, we investigated the prevalence of A. actinomycetemcomitans serotypes and their T4SSs in a Taiwanese population. METHODS A comparative analysis of 20 A. actinomycetemcomitans genomes and their T4SSs deposited in GenBank was performed. One hundred subjects, including 20 periodontitis and 80 normal subjects, were enrolled and PCR identification of A. actinomycetemcomitans serotypes and T4SS genes were performed. RESULTS Of 100 subjects, serotypes C (22%) and E (11%) were most common. In addition, T4SSs were distributed in all of the serotypes. The prevalence of T4SSs and their location in plasmids in periodontitis subjects were 1.28-2 fold higher but not significantly different compared to normal subjects. Of 20 A. actinomycetemcomitans genomes, only ten with complete T4SS modules could be detected, which was highly correlated with localized aggressive periodontitis (p < 0.1). Nine of ten T4SS modules were from periodontitis subjects. Phylogenetic analysis of 10 T4SSs in A. actinomycetemcomitans showed that they were clustered into two groups, T4SSAaI and T4SSAaII, with only T4SSAaI appearing in the Taiwanese subjects. CONCLUSION A. actinomycetemcomitans strains with different serotypes carrying T4SSAaI are widely distributed in a Taiwanese population. This is the first report to show the distribution and detailed comparative genomics of T4SSs in A. actinomycetemcomitans.
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Affiliation(s)
- Chih-Chin Liu
- Department of Bioinformatics, Chung Hua University, Hsin-Chu City, Taiwan; Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan
| | - Chang-Hua Chen
- Division of Infectious Diseases, Department of Internal Medicine, Changhua Christian Hospital, Changhua City, Taiwan; Department of Nursing, College of Medicine & Nursing, Hung Kuang University, Taichung City, Taiwan
| | - Chuan Yi Tang
- Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan
| | - Kuan-Hsueh Chen
- Department of Computer Science and Information Engineering, Providence University, Taichung County, Taiwan
| | - Zhao-Feng Chen
- Department of Nursing, Yuanpei University, Hsin-Chu City, Taiwan
| | - Shih-Hao Chang
- Department of Periodontics, Chang Gung Memorial Hospital, Tao-Yuan County, Taiwan
| | - Chi-Ying Tsai
- Department of Oral Maxillofacial Surgery, Chang Gung Memorial Hospital, Tao-Yuan County, Taiwan
| | - Ming-Li Liou
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University, Hsin-Chu City, Taiwan.
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Johansson A, Claesson R, Höglund Åberg C, Haubek D, Oscarsson J. ThecagEgene sequence as a diagnostic marker to identify JP2 and non-JP2 highly leukotoxicAggregatibacter actinomycetemcomitansserotype b strains. J Periodontal Res 2017; 52:903-912. [DOI: 10.1111/jre.12462] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2017] [Indexed: 12/27/2022]
Affiliation(s)
- A. Johansson
- Division of Molecular Periodontology; Department of Odontology; Umeå University; Umeå Sweden
| | - R. Claesson
- Division of Oral Microbiology; Department of Odontology; Umeå University; Umeå Sweden
| | - C. Höglund Åberg
- Division of Molecular Periodontology; Department of Odontology; Umeå University; Umeå Sweden
| | - D. Haubek
- Section for Pediatric Dentistry; Department of Dentistry and Oral Health; Aarhus University; Aarhus Denmark
| | - J. Oscarsson
- Division of Oral Microbiology; Department of Odontology; Umeå University; Umeå Sweden
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10
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Westhoff S, van Wezel GP, Rozen DE. Distance-dependent danger responses in bacteria. Curr Opin Microbiol 2017; 36:95-101. [PMID: 28258981 DOI: 10.1016/j.mib.2017.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/27/2017] [Accepted: 02/01/2017] [Indexed: 12/23/2022]
Abstract
The last decade has seen a resurgence in our understanding of the diverse mechanisms that bacteria use to kill one another. We are also beginning to uncover the responses and countermeasures that bacteria use when faced with specific threats or general cues of potential danger from bacterial competitors. In this Perspective, we propose that diverse offensive and defensive responses in bacteria have evolved to offset dangers detected at different distances. Thus, while volatile organic compounds provide bacterial cells with a warning at the greatest distance, diffusible compounds like antibiotics or contact mediated killing systems, indicate a more pressing danger warranting highly-specific responses. In the competitive environments in which bacteria live, it is crucial that cells are able to detect real or potential dangers from other cells. By utilizing mechanisms of detection that can infer the distance from danger, bacteria can fine-tune aggressive interactions so that they can optimally respond to threats occurring with distinct levels of risk.
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Affiliation(s)
- Sanne Westhoff
- Institute of Biology, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2300 BE Leiden, The Netherlands.
| | - Gilles P van Wezel
- Institute of Biology, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2300 BE Leiden, The Netherlands
| | - Daniel E Rozen
- Institute of Biology, Leiden University, Sylvius Laboratory, Sylviusweg 72, 2300 BE Leiden, The Netherlands
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Zawilak-Pawlik A, Zakrzewska-Czerwińska J. Recent Advances in Helicobacter pylori Replication: Possible Implications in Adaptation to a Pathogenic Lifestyle and Perspectives for Drug Design. Curr Top Microbiol Immunol 2017; 400:73-103. [PMID: 28124150 DOI: 10.1007/978-3-319-50520-6_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
DNA replication is an important step in the life cycle of every cell that ensures the continuous flow of genetic information from one generation to the next. In all organisms, chromosome replication must be coordinated with overall cell growth. Helicobacter pylori growth strongly depends on its interaction with the host, particularly with the gastric epithelium. Moreover, H. pylori actively searches for an optimal microniche within a stomach, and it has been shown that not every microniche equally supports growth of this bacterium. We postulate that besides nutrients, H. pylori senses different, unknown signals, which presumably also affect chromosome replication to maintain H. pylori propagation at optimal ratio allowing H. pylori to establish a chronic, lifelong infection. Thus, H. pylori chromosome replication and particularly the regulation of this process might be considered important for bacterial pathogenesis. Here, we summarize our current knowledge of chromosome and plasmid replication in H. pylori and discuss the mechanisms responsible for regulating this key cellular process. The results of extensive studies conducted thus far allow us to propose common and unique traits in H. pylori chromosome replication. Interestingly, the repertoire of proteins involved in replication in H. pylori is significantly different to that in E. coli, strongly suggesting that novel factors are engaged in H. pylori chromosome replication and could represent attractive drug targets.
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Affiliation(s)
- Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Ul. Weigla 12, 53-114, Wrocław, Poland.
| | - Jolanta Zakrzewska-Czerwińska
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Ul. Weigla 12, 53-114, Wrocław, Poland
- Department of Molecular Microbiology, Faculty of Biotechnology, University of Wrocław, Ul. Joliot-Curie 14A, 50-383, Wrocław, Poland
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12
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Fercher C, Probst I, Kohler V, Goessweiner-Mohr N, Arends K, Grohmann E, Zangger K, Meyer NH, Keller W. VirB8-like protein TraH is crucial for DNA transfer in Enterococcus faecalis. Sci Rep 2016; 6:24643. [PMID: 27103580 PMCID: PMC4840375 DOI: 10.1038/srep24643] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/04/2016] [Indexed: 12/02/2022] Open
Abstract
Untreatable bacterial infections caused by a perpetual increase of antibiotic resistant strains represent a serious threat to human healthcare in the 21(st) century. Conjugative DNA transfer is the most important mechanism for antibiotic resistance and virulence gene dissemination among bacteria and is mediated by a protein complex, known as type IV secretion system (T4SS). The core of the T4SS is a multiprotein complex that spans the bacterial envelope as a channel for macromolecular secretion. We report the NMR structure and functional characterization of the transfer protein TraH encoded by the conjugative Gram-positive broad-host range plasmid pIP501. The structure exhibits a striking similarity to VirB8 proteins of Gram-negative secretion systems where they play an essential role in the scaffold of the secretion machinery. Considering TraM as the first VirB8-like protein discovered in pIP501, TraH represents the second protein affiliated with this family in the respective transfer operon. A markerless traH deletion in pIP501 resulted in a total loss of transfer in Enterococcus faecalis as compared with the pIP501 wild type (wt) plasmid, demonstrating that TraH is essential for pIP501 mediated conjugation. Moreover, oligomerization state and topology of TraH in the native membrane were determined providing insights in molecular organization of a Gram-positive T4SS.
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Affiliation(s)
- Christian Fercher
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
| | - Ines Probst
- Division of Infectious Diseases, University Medical Center Freiburg, Germany
- Faculty of Biology, Microbiology, Albert-Ludwigs-University Freiburg, Germany
| | - Verena Kohler
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
| | - Nikolaus Goessweiner-Mohr
- Center for Structural System Biology (CSSB), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany
- Institute of Molecular Biotechnology (IMBA), Austrian Academy of Sciences, Vienna, Austria
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | | | - Elisabeth Grohmann
- Division of Infectious Diseases, University Medical Center Freiburg, Germany
- Beuth University of Applied Sciences, Berlin, Germany
| | - Klaus Zangger
- Institute of Chemistry, University of Graz, Graz, Austria
| | - N. Helge Meyer
- Department of General and Visceral Surgery, University of Oldenburg, Germany
| | - Walter Keller
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria
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Habenstein B, Loquet A. Solid-state NMR: An emerging technique in structural biology of self-assemblies. Biophys Chem 2016; 210:14-26. [DOI: 10.1016/j.bpc.2015.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 07/08/2015] [Indexed: 12/13/2022]
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14
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Garita-Cambronero J, Palacio-Bielsa A, López MM, Cubero J. Draft genome sequence for virulent and avirulent strains of Xanthomonas arboricola isolated from Prunus spp. in Spain. Stand Genomic Sci 2016; 11:12. [PMID: 26823958 PMCID: PMC4730658 DOI: 10.1186/s40793-016-0132-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/01/2015] [Indexed: 11/10/2022] Open
Abstract
Xanthomonas arboricola is a species in genus Xanthomonas which is mainly comprised of plant pathogens. Among the members of this taxon, X. arboricola pv. pruni, the causal agent of bacterial spot disease of stone fruits and almond, is distributed worldwide although it is considered a quarantine pathogen in the European Union. Herein, we report the draft genome sequence, the classification, the annotation and the sequence analyses of a virulent strain, IVIA 2626.1, and an avirulent strain, CITA 44, of X. arboricola associated with Prunus spp. The draft genome sequence of IVIA 2626.1 consists of 5,027,671 bp, 4,720 protein coding genes and 50 RNA encoding genes. The draft genome sequence of strain CITA 44 consists of 4,760,482 bp, 4,250 protein coding genes and 56 RNA coding genes. Initial comparative analyses reveals differences in the presence of structural and regulatory components of the type IV pilus, the type III secretion system, the type III effectors as well as variations in the number of the type IV secretion systems. The genome sequence data for these strains will facilitate the development of molecular diagnostics protocols that differentiate virulent and avirulent strains. In addition, comparative genome analysis will provide insights into the plant-pathogen interaction during the bacterial spot disease process.
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Affiliation(s)
| | - Ana Palacio-Bielsa
- />Centro de Investigación y Tecnología Agroalimentaria de Aragón, Zaragoza, Spain
| | - María M. López
- />Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | - Jaime Cubero
- />Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain
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15
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Abstract
Horizontal gene transfer plays a major role in microbial evolution, allowing microbes to acquire new genes and phenotypes. Integrative and conjugative elements (ICEs, a.k.a. conjugative transposons) are modular mobile genetic elements integrated into a host genome and are passively propagated during chromosomal replication and cell division. Induction of ICE gene expression leads to excision, production of the conserved conjugation machinery (a type IV secretion system), and the potential to transfer DNA to appropriate recipients. ICEs typically contain cargo genes that are not usually related to the ICE life cycle and that confer phenotypes to host cells. We summarize the life cycle and discovery of ICEs, some of the regulatory mechanisms, and how the types of cargo have influenced our view of ICEs. We discuss how ICEs can acquire new cargo genes and describe challenges to the field and various perspectives on ICE biology.
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Affiliation(s)
- Christopher M Johnson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; ,
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16
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Kaplan M, Cukkemane A, van Zundert GCP, Narasimhan S, Daniëls M, Mance D, Waksman G, Bonvin AMJJ, Fronzes R, Folkers GE, Baldus M. Probing a cell-embedded megadalton protein complex by DNP-supported solid-state NMR. Nat Methods 2015; 12:649-52. [PMID: 25984698 DOI: 10.1038/nmeth.3406] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 03/25/2015] [Indexed: 12/24/2022]
Abstract
Studying biomolecules at atomic resolution in their native environment is the ultimate aim of structural biology. We investigated the bacterial type IV secretion system core complex (T4SScc) by cellular dynamic nuclear polarization-based solid-state nuclear magnetic resonance spectroscopy to validate a structural model previously generated by combining in vitro and in silico data. Our results indicate that T4SScc is well folded in the cellular setting, revealing protein regions that had been elusive when studied in vitro.
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Affiliation(s)
- Mohammed Kaplan
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | | | | | | | - Mark Daniëls
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Deni Mance
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, UK
| | | | - Rémi Fronzes
- Groupe à 5 ans, Biologie structurale de la secretion bacterienne, Unité mixte de recherche Centre National de la Recherche Scientifique-Institut Pasteur 3528, Institut Pasteur, Paris, France
| | - Gert E Folkers
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
| | - Marc Baldus
- NMR Spectroscopy, Utrecht University, Utrecht, the Netherlands
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17
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Bacterial killing via a type IV secretion system. Nat Commun 2015; 6:6453. [PMID: 25743609 DOI: 10.1038/ncomms7453] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/29/2015] [Indexed: 12/24/2022] Open
Abstract
Type IV secretion systems (T4SSs) are multiprotein complexes that transport effector proteins and protein-DNA complexes through bacterial membranes to the extracellular milieu or directly into the cytoplasm of other cells. Many bacteria of the family Xanthomonadaceae, which occupy diverse environmental niches, carry a T4SS with unknown function but with several characteristics that distinguishes it from other T4SSs. Here we show that the Xanthomonas citri T4SS provides these cells the capacity to kill other Gram-negative bacterial species in a contact-dependent manner. The secretion of one type IV bacterial effector protein is shown to require a conserved C-terminal domain and its bacteriolytic activity is neutralized by a cognate immunity protein whose 3D structure is similar to peptidoglycan hydrolase inhibitors. This is the first demonstration of the involvement of a T4SS in bacterial killing and points to this special class of T4SS as a mediator of both antagonistic and cooperative interbacterial interactions.
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18
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Hwang HH, Liu YT, Huang SC, Tung CY, Huang FC, Tsai YL, Cheng TF, Lai EM. Overexpression of the HspL Promotes Agrobacterium tumefaciens Virulence in Arabidopsis Under Heat Shock Conditions. PHYTOPATHOLOGY 2015; 105:160-168. [PMID: 25163013 DOI: 10.1094/phyto-05-14-0133-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Agrobacterium tumefaciens transfers a specific DNA fragment from the resident tumor-inducing (Ti) plasmid and effector virulence (Vir) proteins to plant cells during infection. A. tumefaciens VirB1-11 and VirD4 proteins assemble as the type IV secretion system (T4SS), which mediates transfer of the T-DNA and effector Vir protein into plant cells, thus resulting in crown gall disease in plants. Previous studies revealed that an α-crystallin-type, small heat-shock protein (HspL) is a more effective VirB8 chaperone than three other small heat-shock proteins (HspC, HspAT1, and HspAT2). Additionally, HspL contributes to efficient T4SS-mediated DNA transfer and tumorigenesis under room-temperature growth. In this study, we aimed to characterize the impact of HspL on Agrobacterium-mediated transformation efficiency under heat-shock treatment. During heat shock, transient transformation efficiency and VirB8 protein accumulation were lower in the hspL deletion mutant than in the wild type. Overexpression of HspL in A. tumefaciens enhanced the transient transformation efficiency in root explants of both susceptible and recalcitrant Arabidopsis ecotypes. In addition, the reduced transient transformation efficiency during heat stress was recovered by overexpression of HspL in A. tumefaciens. HspL may help maintain VirB8 homeostasis and elevate Agrobacterium-mediated transformation efficiency under both heat-shock and nonheat-shock growth.
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Abstract
Resistance of important bacterial pathogens to common antimicrobial therapies and the emergence of multidrug-resistant bacteria are increasing at an alarming rate and constitute one of our greatest challenges in the combat of bacterial infection and accompanied diseases. The current shortage of effective drugs, lack of successful prevention measures and only a few new antibiotics in the clinical pipeline demand the development of novel treatment options and alternative antimicrobial therapies. Our increasing understanding of bacterial virulence strategies and the induced molecular pathways of the infectious disease provides novel opportunities to target and interfere with crucial pathogenicity factors or virulence-associated traits of the bacteria while bypassing the evolutionary pressure on the bacterium to develop resistance. In the past decade, numerous new bacterial targets for anti-virulence therapies have been identified, and structure-based tailoring of intervention strategies and screening assays for small-molecule inhibitors of such pathways were successfully established. In this chapter, we will take a closer look at the bacterial virulence-related factors and processes that present promising targets for anti-virulence therapies, recently discovered inhibitory substances and their promises and discuss the challenges, and problems that have to be faced.
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Comparative Genome Analysis of Two Isolates of the Fish Pathogen Piscirickettsia salmonis from Different Hosts Reveals Major Differences in Virulence-Associated Secretion Systems. GENOME ANNOUNCEMENTS 2014; 2:2/6/e01219-14. [PMID: 25523762 PMCID: PMC4271152 DOI: 10.1128/genomea.01219-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Outbreaks caused by Piscirickettsia salmonis are one of the major threats to the sustainability of the Chilean salmon industry. We report here the annotated draft genomes of two P. salmonis isolates recovered from different salmonid species. A comparative analysis showed that the number of virulence-associated secretion systems constitutes a main genomic difference.
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21
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Cabezón E, Ripoll-Rozada J, Peña A, de la Cruz F, Arechaga I. Towards an integrated model of bacterial conjugation. FEMS Microbiol Rev 2014; 39:81-95. [PMID: 25154632 DOI: 10.1111/1574-6976.12085] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacterial conjugation is one of the main mechanisms for horizontal gene transfer. It constitutes a key element in the dissemination of antibiotic resistance and virulence genes to human pathogenic bacteria. DNA transfer is mediated by a membrane-associated macromolecular machinery called Type IV secretion system (T4SS). T4SSs are involved not only in bacterial conjugation but also in the transport of virulence factors by pathogenic bacteria. Thus, the search for specific inhibitors of different T4SS components opens a novel approach to restrict plasmid dissemination. This review highlights recent biochemical and structural findings that shed new light on the molecular mechanisms of DNA and protein transport by T4SS. Based on these data, a model for pilus biogenesis and substrate transfer in conjugative systems is proposed. This model provides a renewed view of the mechanism that might help to envisage new strategies to curb the threating expansion of antibiotic resistance.
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Affiliation(s)
- Elena Cabezón
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Jorge Ripoll-Rozada
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Alejandro Peña
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Fernando de la Cruz
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Ignacio Arechaga
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
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