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https://www.readbyqxmd.com/read/28536678/the-role-and-mechanism-of-erythrocyte-invasion-by-francisella-tularensis
#1
Deanna M Schmitt, Rebecca Barnes, Taylor Rogerson, Ashley Haught, Leanne K Mazzella, Matthew Ford, Tricia Gilson, James W-M Birch, Anders Sjöstedt, Douglas S Reed, Jonathan M Franks, Donna B Stolz, James Denvir, Jun Fan, Swanthana Rekulapally, Donald A Primerano, Joseph Horzempa
Francisella tularensis is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells (RBCs) has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28487352/in-vivo-structures-of-an-intact-type-vi-secretion-system-revealed-by-electron-cryotomography
#2
Yi-Wei Chang, Lee A Rettberg, Davi R Ortega, Grant J Jensen
The type VI secretion system (T6SS) is a versatile molecular weapon used by many bacteria against eukaryotic hosts or prokaryotic competitors. It consists of a cytoplasmic bacteriophage tail-like structure anchored in the bacterial cell envelope via a cytoplasmic baseplate and a periplasmic membrane complex. Rapid contraction of the sheath in the bacteriophage tail-like structure propels an inner tube/spike complex through the target cell envelope to deliver effectors. While structures of purified contracted sheath and purified membrane complex have been solved, because sheaths contract upon cell lysis and purification, no structure is available for the extended sheath...
May 9, 2017: EMBO Reports
https://www.readbyqxmd.com/read/28452085/use-of-chimeric-type-iv-secretion-systems-to-define-contributions-of-outer-membrane-subassemblies-for-contact-dependent-translocation
#3
Jay E Gordon, Tiago R D Costa, Roosheel S Patel, Christian Gonzalez-Rivera, Mayukh K Sarkar, Elena V Orlova, Gabriel Waksman, Peter J Christie
Recent studies have shown that conjugation systems of Gram-negative bacteria are composed of distinct inner and outer membrane core complexes (IMCs and OMCCs, respectively). Here, we functionally characterized the OMCC, focusing first on a cap domain that forms a channel across the outer membrane. Strikingly, the OMCC caps of the Escherichia coli pKM101 Tra and Agrobacterium tumefaciens VirB/VirD4 systems are completely dispensable for substrate transfer, but required for formation of conjugative pili. The pKM101 OMCC cap and extended pilus also are dispensable for activation of a Pseudomonas aeruginosa type VI secretion system (T6SS)...
April 27, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28448786/microbiological-features-and-clinical-impact-of-the-type-vi-secretion-system-t6ss-in-acinetobacter-baumannii-isolates-causing-bacteremia
#4
Jungok Kim, Ji-Young Lee, Haejeong Lee, Ji Young Choi, Dae Hun Kim, Yu Mi Wi, Kyong Ran Peck, Kwan Soo Ko
We investigated the genetic background and microbiological features of T6SS-positive Acinetobacter baumannii isolates and clinical impact of the T6SS in patients with A. baumannii bacteremia. One hundred and sixty-two A. baumannii isolates from patients with bacteremia in two tertiary-care hospitals in Korea were included in this study. Approximately one-third (51/162, 31.5%) of the A. baumannii clinical isolates possessed the hcp gene, and the hcp-positive isolates were found in several genotypes in multilocus sequence typing...
April 27, 2017: Virulence
https://www.readbyqxmd.com/read/28441105/transcriptomic-dissection-of-the-horizontally-acquired-response-regulator-esrb-reveals-its-global-regulatory-roles-in-the-physiological-adaptation-and-activation-of-t3ss-and-the-cognate-effector-repertoire-in-edwardsiella-piscicida-during-infection-towards
#5
Yang Liu, Luyao Zhao, Minjun Yang, Kaiyu Yin, Xiaohui Zhou, Ka Yin Leung, Qin Liu, Yuanxing Zhang, Qiyao Wang
Edwardsiella piscicida is the leading pathogen threatening worldwide aquaculture industries. The two-component system (TCS) EsrA-EsrB is essential for the pathogenesis of this bacterium. However, little is known about the regulon and regulatory mechanism of EsrA-EsrB or about the factors that mediate the interaction of TCS with bacterial hosts. Here, our RNA-seq analysis indicated that EsrB strongly induces type III and type VI secretion systems (T3/T6SS) expression and that it modulates the expression of both physiology- and virulence-associated genes in E...
April 25, 2017: Virulence
https://www.readbyqxmd.com/read/28432099/acute-hepatopancreatic-necrosis-disease-ahpnd-causing-vibrio-parahaemolyticus-strains-maintain-an-antibacterial-type-vi-secretion-system-with-versatile-effector-repertoires
#6
Peng Li, Lisa N Kinch, Ann Ray, Ankur B Dalia, Qian Cong, Linda M Nunan, Andrew Camilli, Nick V Grishin, Dor Salomon, Kim Orth
Acute hepatopancreatic necrosis disease (AHPND) is a newly emerging shrimp disease that has severely damaged the global shrimp industry. AHPND is caused by toxic strains of Vibrio parahaemolyticus (V. parahaemolyticus) that have acquired a "selfish plasmid" encoding the deadly binary toxins PirA(vp)/PirB(vp) To better understand the repertoire of virulence factors in AHPND-causing V. parahaemolyticus, we conducted a comparative analysis using genome sequences of the clinical strain RIMD2210633, environmental non-AHPND and toxic AHPND isolates of V...
April 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28430102/variable-virulence-phenotype-of-xenorhabdus-bovienii-%C3%AE-proteobacteria-enterobacteriaceae-in-the-absence-of-their-vector-hosts
#7
John G McMullen, Rebecca McQuade, Jean-Claude Ogier, Sylvie Pagès, Sophie Gaudriault, S Patricia Stock
Xenorhabdus bovienii bacteria have a dual lifestyle: they are mutualistic symbionts to many species of Steinernema nematodes and are pathogens to a wide array of insects. Previous studies have shown that virulence of X.bovienii-Steinernema spp. pairs decreases when the nematodes associate with non-cognate bacterial strains. However, the virulence of the X. bovienii strains alone has not been fully investigated. In this study, we characterized the virulence of nine X. bovienii strains in Galleria mellonella and Spodoptera littoralis and performed a comparative genomic analysis to correlate observed phenotypes with strain genotypes...
April 22, 2017: Microbiology
https://www.readbyqxmd.com/read/28424671/functional-characterization-and-conditional-regulation-of-the-type-vi-secretion-system-in-vibrio-fluvialis
#8
Yuanming Huang, Pengcheng Du, Meng Zhao, Wei Liu, Yu Du, Baowei Diao, Jie Li, Biao Kan, Weili Liang
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...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28421913/type-vi-secretion-systems-of-erwinia-amylovora-contribute-to-bacterial-competition-virulence-and-exopolysaccharide-production
#9
Yanli Tian, Yuqiang Zhao, Linye Shi, Zhongli Cui, Baishi Hu, Youfu Zhao
The type VI secretion system (T6SS) plays a major role in mediating interbacterial competition and might contribute to virulence in plant pathogenic bacteria. However, the role of T6SS in Erwinia amylovora remains unknown. In this study, 33 deletion mutants within three T6SS clusters were generated in E. amylovora strain NCPPB1665. Our results showed that all 33 mutants displayed reduced antibacterial activities against Escherichia coli as compared with that of the wild-type (WT) strain, indicating that Erwinia amylovora T6SS are functional...
June 2017: Phytopathology
https://www.readbyqxmd.com/read/28357328/francisella-iglg-protein-and-the-duf4280-proteins-paar-like-proteins-in-non-canonical-type-vi-secretion-systems
#10
COMMENT
Claire Lays, Eric Tannier, Thomas Henry
Type VI secretion systems (T6SS) are bacterial molecular machines translocating effector proteins into target cells. T6SS are widely present in Gram-negative bacteria where they predominantly act to kill neighboring bacteria. This secretion system is reminiscent of the tail of contractile bacteriophages and consists of a contractile sheath anchored in the bacterial envelope and an inner tube made of stacks of the Hcp protein. The Hcp tube is capped with a VgrG trimer and a spike protein termed PAAR, which acts as the membrane-puncturing device...
October 29, 2016: Microbial Cell
https://www.readbyqxmd.com/read/28348642/metagenomic-analysis-of-a-complex-community-present-in-pond-sediment
#11
Vivek Negi, Rup Lal
The metagenomic profiling of complex communities is gaining immense interest across the scientific community. A complex community present in the pond sediment of a water body located close to a hexachlorocyclohexane (HCH) production site of the Indian Pesticide Limited (IPL) (Chinhat, Lucknow) was selected in an attempt to identify and analyze the unique microbial diversity and functional profile of the site. In this study, we supplement the metagenomic study of pond sediment with a variety of binning approaches along with an in depth functional analysis...
2017: Journal of Genomics
https://www.readbyqxmd.com/read/28348410/a-pseudomonas-t6ss-effector-recruits-pqs-containing-outer-membrane-vesicles-for-iron-acquisition
#12
Jinshui Lin, Weipeng Zhang, Juanli Cheng, Xu Yang, Kaixiang Zhu, Yao Wang, Gehong Wei, Pei-Yuan Qian, Zhao-Qing Luo, Xihui Shen
Iron sequestration by host proteins contributes to the defence against bacterial pathogens, which need iron for their metabolism and virulence. A Pseudomonas aeruginosa mutant lacking all three known iron acquisition systems retains the ability to grow in media containing iron chelators, suggesting the presence of additional pathways involved in iron uptake. Here we screen P. aeruginosa mutants defective in growth in iron-depleted media and find that gene PA2374, proximal to the type VI secretion system H3 (H3-T6SS), functions synergistically with known iron acquisition systems...
March 28, 2017: Nature Communications
https://www.readbyqxmd.com/read/28327641/sequential-displacement-of-type-vi-secretion-system-effector-genes-leads-to-evolution-of-diverse-immunity-gene-arrays-in-vibrio-cholerae
#13
Paul C Kirchberger, Daniel Unterweger, Daniele Provenzano, Stefan Pukatzki, Yan Boucher
Type VI secretion systems (T6SS) enable bacteria to engage neighboring cells in contact-dependent competition. In Vibrio cholerae, three chromosomal clusters each encode a pair of effector and immunity genes downstream of those encoding the T6SS structural machinery for effector delivery. Different combinations of effector-immunity proteins lead to competition between strains of V. cholerae, which are thought to be protected only from the toxicity of their own effectors. Screening of all publically available V...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28288207/type-vi-secretion-system-contributes-to-enterohemorrhagic-escherichia-coli-virulence-by-secreting-catalase-against-host-reactive-oxygen-species-ros
#14
Baoshan Wan, Qiufen Zhang, Jinjing Ni, Shuxian Li, Donghua Wen, Jun Li, Haihan Xiao, Ping He, Hong-Yu Ou, Jing Tao, Qihui Teng, Jie Lu, Wenjuan Wu, Yu-Feng Yao
Enterohemorrhagic Escherichia coli (EHEC) is one major type of contagious and foodborne pathogens. The type VI secretion system (T6SS) has been shown to be involved in the bacterial pathogenicity and bacteria-bacteria competition. Here, we show that EHEC could secrete a novel effector KatN, a Mn-containing catalase, in a T6SS-dependent manner. Expression of katN is promoted by RpoS and OxyR and repressed by H-NS, and katN contributes to bacterial growth under oxidative stress in vitro. KatN could be secreted into host cell cytosol after EHEC is phagocytized by macrophage, which leads to decreased level of intracellular reactive oxygen species (ROS) and facilitates the intramacrophage survival of EHEC...
March 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28281200/zntr-positively-regulates-t6ss4-expression-in-yersinia-pseudotuberculosis
#15
Tietao Wang, Keqi Chen, Fen Gao, Yiwen Kang, Muhammad Tausif Chaudhry, Zhuo Wang, Yao Wang, Xihui Shen
The type VI secretion system (T6SS) is a widespread and versatile protein secretion system found in most Gramnegative bacteria. Studies of T6SS have mainly focused on its role in virulence toward host cells and inter-bacterial interactions, but studies have also shown that T6SS4 in Yersinia pseudotuberculosis participates in the acquisition of zinc ions to alleviate the accumulation of hydroxyl radicals induced by multiple stressors. Here, by comparing the gene expression patterns of wild-type and zntR mutant Y...
March 10, 2017: Journal of Microbiology / the Microbiological Society of Korea
https://www.readbyqxmd.com/read/28277899/don-t-judge-a-book-by-its-cover-the-hcps-are-not-only-structural-components-of-the-t6ss-machinery
#16
Sophie Bleves
No abstract text is available yet for this article.
March 1, 2017: Virulence
https://www.readbyqxmd.com/read/28264992/crispr-cas-and-contact-dependent-secretion-systems-present-on-excisable-pathogenicity-islands-with-conserved-recombination-modules
#17
Megan R Carpenter, Sai S Kalburge, Joseph D Borowski, Molly C Peters, Rita R Colwell, E Fidelma Boyd
Pathogenicity islands (PAIs) are mobile integrated genetic elements that contain a diverse range of virulence factors. PAIs integrate into the host chromosome at a tRNA locus that contains their specific bacterial attachment site, attB, via integrase-mediated site-specific recombination generating attL and attR sites. We identified conserved recombination modules (integrases and att sites) previously described in choleragenic Vibrio cholerae PAIs but with novel cargo genes. Clustered regularly interspaced short palindromic repeat (CRISPR)-associated proteins (Cas proteins) and a type VI secretion system (T6SS) gene cluster were identified at the Vibrio pathogenicity island 1 (VPI-1) insertion site in 19 V...
May 15, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28242693/manganese-scavenging-and-oxidative-stress-response-mediated-by-type-vi-secretion-system-in-burkholderia-thailandensis
#18
Meiru Si, Chao Zhao, Brianne Burkinshaw, Bing Zhang, Dawei Wei, Yao Wang, Tao G Dong, Xihui Shen
Type VI secretion system (T6SS) is a versatile protein export machinery widely distributed in Gram-negative bacteria. Known to translocate protein substrates to eukaryotic and prokaryotic target cells to cause cellular damage, the T6SS has been primarily recognized as a contact-dependent bacterial weapon for microbe-host and microbial interspecies competition. Here we report contact-independent functions of the T6SS for metal acquisition, bacteria competition, and resistance to oxidative stress. We demonstrate that the T6SS-4 in Burkholderia thailandensis is critical for survival under oxidative stress and is regulated by OxyR, a conserved oxidative stress regulator...
March 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28236274/comparative-pan-genome-analysis-of-oral-prevotella-species-implicated-in-periodontitis
#19
Maziya Ibrahim, Ahalyaa Subramanian, Sharmila Anishetty
Prevotella is part of the oral bacterial community implicated in periodontitis. Pan genome analyses of eight oral Prevotella species, P. dentalis, P. enoeca, P. fusca, P. melaninogenica, P. denticola, P. intermedia 17, P. intermedia 17-2 and P. sp. oral taxon 299 are presented in this study. Analysis of the Prevotella pan genome revealed features such as secretion systems, resistance to oxidative stress and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas systems that enable the bacteria to adapt to the oral environment...
February 24, 2017: Functional & Integrative Genomics
https://www.readbyqxmd.com/read/28217442/whole-genome-sequencing-and-analysis-of-campylobacter-coli-yh502-from-retail-chicken-reveals-a-plasmid-borne-type-vi-secretion-system
#20
Sandeep Ghatak, Yiping He, Sue Reed, Terence Strobaugh, Peter Irwin
Campylobacter is a major cause of foodborne illnesses worldwide. Campylobacter infections, commonly caused by ingestion of undercooked poultry and meat products, can lead to gastroenteritis and chronic reactive arthritis in humans. Whole genome sequencing (WGS) is a powerful technology that provides comprehensive genetic information about bacteria and is increasingly being applied to study foodborne pathogens: e.g., evolution, epidemiology/outbreak investigation, and detection. Herein we report the complete genome sequence of Campylobacter coli strain YH502 isolated from retail chicken in the United States...
March 2017: Genomics Data
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