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https://www.readbyqxmd.com/read/29326272/antagonism-toward-the-intestinal-microbiota-and-its-effect-on-vibrio-cholerae-virulence
#1
Wenjing Zhao, Florence Caro, William Robins, John J Mekalanos
The bacterial type VI secretion system (T6SS) is a nanomachine that delivers toxic effector proteins into target cells, killing them. In mice, we found that the Vibrio cholerae T6SS attacks members of the host commensal microbiota in vivo, facilitating the pathogen's colonization of the gut. This microbial antagonistic interaction drives measurable changes in the pathogenicity of V. cholerae through enhanced intestinal colonization, expression of bacterial virulence genes, and activation of host innate immune genes...
January 12, 2018: Science
https://www.readbyqxmd.com/read/29314504/serine-threonine-kinase-ppka-coordinates-the-interplay-between-t6ss2-activation-and-quorum-sensing-in-the-marine-pathogen-vibrio-alginolyticus
#2
Zhen Yang, Xiaohui Zhou, Yue Ma, Mian Zhou, Matthew K Waldor, Yuanxing Zhang, Qiyao Wang
Type VI secretion systems (T6SS) are multiprotein secretion machines that can mediate killing of bacterial cells and thereby modify the composition of bacterial communities. The mechanisms that control the production of and secretion of these killing machines are incompletely understood, although quorum sensing (QS) and the PpkA kinase modulate T6SS activity in some organisms. Here we investigated control the T6S in the marine organism Vibrio alginolyticus EPGS, which encodes two T6SS systems (T6SS1 and T6SS2)...
January 4, 2018: Environmental Microbiology
https://www.readbyqxmd.com/read/29307484/atomic-structure-of-type-vi-contractile-sheath-from-pseudomonas-aeruginosa
#3
Osman Salih, Shaoda He, Sara Planamente, Lasse Stach, James T MacDonald, Eleni Manoli, Sjors H W Scheres, Alain Filloux, Paul S Freemont
Pseudomonas aeruginosa has three type VI secretion systems (T6SSs), H1-, H2-, and H3-T6SS, each belonging to a distinct group. The two T6SS components, TssB/VipA and TssC/VipB, assemble to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins. Here, we used cryoelectron microscopy to solve the structure of the H1-T6SS P. aeruginosa TssB1C1 sheath at 3.3 Å resolution. Our structure allowed us to resolve some features of the T6SS sheath that were not resolved in the Vibrio cholerae VipAB and Francisella tularensis IglAB structures...
December 21, 2017: Structure
https://www.readbyqxmd.com/read/29281838/the-role-of-type-vi-secretion-system-effectors-in-target-cell-lysis-and-subsequent-horizontal-gene-transfer
#4
Peter David Ringel, Di Hu, Marek Basler
Bacteria use type VI secretion systems (T6SSs) to manipulate host cells during pathogenesis or to kill competing bacteria, which, in some cases, increases horizontal gene transfer. These functions largely depend on T6SS regulation, dynamics, and the set of effectors that the system delivers into the target cells. Here, we show that Acinetobacter baylyi ADP1 assembles a highly dynamic T6SS capable of killing and lysing bacterial cells. T6SS function depends on conserved T6SS components as well as Acinetobacter-specific genes of unknown function...
December 26, 2017: Cell Reports
https://www.readbyqxmd.com/read/29260646/epidemiology-of-campylobacter-infections-among-children-in-egypt
#5
Rebecca Sainato, Atef ElGendy, Frédéric Poly, Janelle Kuroiwa, Patricia Guerry, Mark S Riddle, Chad K Porter
Campylobacter is a frequently isolated bacterial pathogen among children with diarrhea. Data are lacking on the distribution and spectrum of disease associated with Campylobacter species and Campylobacter jejuni capsular polysaccharide (CPS) types. This information is essential because current vaccine research seeks to target specific CPS types. An effective CPS-conjugate vaccine will need to cover CPS types that are both common and associated with severe disease. The US Naval Medical Research Unit-3 conducted several prospective cohort studies researching diarrheal disease in Egypt from 1995 to 2003...
December 18, 2017: American Journal of Tropical Medicine and Hygiene
https://www.readbyqxmd.com/read/29255010/cryo-em-reconstruction-of-type-vi-secretion-system-baseplate-and-sheath-distal-end
#6
Sergey Nazarov, Johannes P Schneider, Maximilian Brackmann, Kenneth N Goldie, Henning Stahlberg, Marek Basler
The bacterial Type VI secretion system (T6SS) assembles from three major parts: a membrane complex that spans inner and outer membranes, a baseplate, and a sheath-tube polymer. The baseplate assembles around a tip complex with associated effectors and connects to the membrane complex by TssK. The baseplate assembly initiates sheath-tube polymerization, which in some organisms requires TssA. Here, we analyzed both ends of isolated non-contractile Vibrio cholerae sheaths by cryo-electron microscopy. Our analysis suggests that the baseplate, solved to an average 8...
December 18, 2017: EMBO Journal
https://www.readbyqxmd.com/read/29237732/diverse-nadase-effector-families-mediate-interbacterial-antagonism-via-the-type-vi-secretion-system
#7
Jenny Y Tang, Nathan P Bullen, Shehryar Ahmad, John C Whitney
The bacterial type VI secretion system (T6SS) mediates antagonistic cell-cell interactions between competing Gram-negative bacteria. In plant-beneficial bacteria, this pathway has been shown to suppress the growth of bacterial pathogens; however, the identification and mode of action of T6SS effector proteins that mediate this protective effect remain poorly defined. Here, we identify two previously uncharacterized effectors required for interbacterial antagonism by the plant commensal bacterium Pseudomonas protegens...
December 13, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29233893/diversification-of-type-vi-secretion-system-toxins-reveals-ancient-antagonism-among-bee-gut-microbes
#8
Margaret I Steele, Waldan K Kwong, Marvin Whiteley, Nancy A Moran
Microbial communities are shaped by interactions among their constituent members. Some Gram-negative bacteria employ type VI secretion systems (T6SSs) to inject protein toxins into neighboring cells. These interactions have been theorized to affect the composition of host-associated microbiomes, but the role of T6SSs in the evolution of gut communities is not well understood. We report the discovery of two T6SSs and numerous T6SS-associated Rhs toxins within the gut bacteria of honey bees and bumble bees. We sequenced the genomes of 28 strains of Snodgrassella alvi, a characteristic bee gut microbe, and found tremendous variability in their Rhs toxin complements: altogether, these strains appear to encode hundreds of unique toxins...
December 12, 2017: MBio
https://www.readbyqxmd.com/read/29223729/structure-function-analysis-of-the-c-terminal-domain-of-the-type-vi-secretion-tssb-tail-sheath-subunit
#9
Badreddine Douzi, Laureen Logger, Silvia Spinelli, Stéphanie Blangy, Christian Cambillau, Eric Cascales
The Type VI secretion system (T6SS) is a specialized macromolecular complex dedicated to the delivery of protein effectors into both eukaryotic and bacterial cells. The general mechanism of action of the T6SS is similar to the injection of DNA by contractile bacteriophages. The cytoplasmic portion of the T6SS is evolutionarily, structurally and functionally related to the phage tail complex. It is composed of an inner tube made of stacked Hcp hexameric rings, engulfed within a sheath and built on a baseplate...
December 6, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/29222345/type-vi-secretion-system-sheath-inter-subunit-interactions-modulate-its-contraction
#10
Maximilian Brackmann, Jing Wang, Marek Basler
Secretion systems are essential for bacteria to survive and manipulate their environment. The bacterial type VI secretion system (T6SS) generates the force needed for protein translocation by the contraction of a long polymer called sheath. The sheath is a six-start helical assembly of interconnected VipA/VipB subunits. The mechanism of T6SS sheath contraction is unknown. Here, we show that elongating the N-terminal VipA linker or eliminating charge of a specific VipB residue abolishes sheath contraction and delivery of effectors into target cells...
December 8, 2017: EMBO Reports
https://www.readbyqxmd.com/read/29163390/comparative-genomics-reveals-specific-genetic-architectures-in-nicotine-metabolism-of-pseudomonas-sp-jy-q
#11
Jun Li, Shulan Qian, Lie Xiong, Chengyun Zhu, Ming Shu, Jie Wang, Yang Jiao, Houlong He, Fuming Zhang, Robert J Linhardt, Weihong Zhong
Microbial degradation of nicotine is an important process to control nicotine residues in the aqueous environment. In this study, a high active nicotine degradation strain named Pseudomonas sp. JY-Q was isolated from tobacco waste extract (TWE). This strain could completely degrade 5.0 g l(-1) nicotine in 24 h under optimal culture conditions, and it showed some tolerance even at higher concentrations (10.0 g l(-1)) of nicotine. The complete genome of JY-Q was sequenced to understand the mechanism by which JY-Q could degrade nicotine and tolerate such high nicotine concentrations...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29155899/subtle-variation-within-conserved-effector-operon-gene-products-contributes-to-t6ss-mediated-killing-and-immunity
#12
Christopher J Alteri, Stephanie D Himpsl, Kevin Zhu, Haley L Hershey, Ninette Musili, Jessa E Miller, Harry L T Mobley
Type VI secretion systems (T6SS) function to deliver lethal payloads into target cells. Many studies have shown that protection against a single, lethal T6SS effector protein requires a cognate antidote immunity protein, both of which are often encoded together in a two-gene operon. The T6SS and an effector-immunity pair is sufficient for both killing and immunity. HereIn this paper we describe a T6SS effector operon that differs from conventional effector-immunity pairs in that eight genes are necessary for lethal effector function, yet can be countered by a single immunity protein...
November 20, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/29147941/artificial-bio-nanomachines-based-on-protein-needles-derived-from-bacteriophage-t4
#13
REVIEW
Hiroshi Inaba, Takafumi Ueno
Bacteriophage T4 is a natural bio-nanomachine which achieves efficient infection of host cells via cooperative motion of specific three-dimensional protein architectures. The relationships between the protein structures and their dynamic functions have recently been clarified. In this review we summarize the design principles for fabrication of nanomachines using the component proteins of bacteriophage T4 based on these recent advances. We focus on the protein needle known as gp5, which is located at the center of the baseplate at the end of the contractile tail of bacteriophage T4...
November 16, 2017: Biophysical Reviews
https://www.readbyqxmd.com/read/29109705/complete-genome-sequence-of-vibrio-campbellii-lmb-29-isolated-from-red-drum-with-four-native-megaplasmids
#14
Jinxin Liu, Zhe Zhao, Yiqing Deng, Yan Shi, Yupeng Liu, Chao Wu, Peng Luo, Chaoqun Hu
Vibrio spp. are the most common pathogens for animals reared in aquaculture. Vibrio campbellii, which is often involved in shrimp, fish and mollusks diseases, is widely distributed in the marine environment worldwide, but our knowledge about its pathogenesis and antimicrobial resistance is very limited. The existence of this knowledge gap is at least partially because that V. campbellii was originally classified as Vibrio harveyi, and the detailed information of its comparative genome analysis to other Vibrio spp...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29090192/identification-of-new-virulence-factors-and-vaccine-candidates-for-yersinia-pestis
#15
Jourdan A Andersson, Jian Sha, Tatiana E Erova, Eric C Fitts, Duraisamy Ponnusamy, Elena V Kozlova, Michelle L Kirtley, Ashok K Chopra
Earlier, we reported the identification of new virulence factors/mechanisms of Yersinia pestis using an in vivo signature-tagged mutagenesis (STM) screening approach. From this screen, the role of rbsA, which encodes an ATP-binding protein of ribose transport system, and vasK, an essential component of the type VI secretion system (T6SS), were evaluated in mouse models of plague and confirmed to be important during Y. pestis infection. However, many of the identified genes from the screen remained uncharacterized...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29085808/identification-and-characterization-of-an-antibacterial-type-vi-secretion-system-in-the-carbapenem-resistant-strain-klebsiella-pneumoniae-hs11286
#16
Lu Liu, Meiping Ye, Xiaobin Li, Jun Li, Zixin Deng, Yu-Feng Yao, Hong-Yu Ou
The type VI secretion system (T6SS) is a class of sophisticated cell contact-dependent apparatus with anti-eukaryotic or anti-bacterial function. Klebsiella pneumoniae is one of the most common bacterial pathogens with resistance to the carbapenem antibiotics. However, little is known about the antibacterial T6SS in K. pneumoniae. Using core-component protein searches, we identified a putative T6SS gene cluster on the chromosome of the carbapenemase-producing K. pneumoniae (CRKP) strain HS11286. Intraspecies and interspecies competition assays revealed an antibacterial function of the HS11286 T6SS...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/29031453/whole-genome-comparison-of-urinary-pathogenic-escherichia-coli-and-faecal-isolates-of-uti-patients-and-healthy-controls
#17
Karen Leth Nielsen, Marc Stegger, Kristoffer Kiil, Paul A Godfrey, Michael Feldgarden, Berit Lilje, Paal S Andersen, Niels Frimodt-Møller
The faecal flora is a common reservoir for urinary tract infection (UTI), and Escherichia coli (E. coli) is frequently found in this reservoir without causing extraintestinal infection. We investigated these E. coli reservoirs by whole-genome sequencing a large collection of E. coli from healthy controls (faecal), who had never previously had UTI, and from UTI patients (faecal and urinary) sampled from the same geographical area. We compared MLST types, phylogenetic relationship, accessory genome content and FimH type between patient and control faecal isolates as well as between UTI and faecal-only isolates, respectively...
September 14, 2017: International Journal of Medical Microbiology: IJMM
https://www.readbyqxmd.com/read/29027348/type-vi-secretion-systems-in-plant-associated-bacteria
#18
Patricia Bernal, María A Llamas, Alain Filloux
The type VI secretion system (T6SS) is a bacterial nanomachine used to inject effectors into prokaryotic or eukaryotic cells and is thus involved in both host manipulation and inter-bacterial competition. The T6SS is widespread among Gram-negative bacteria, mostly within the Proteobacterium Phylum. This secretion system is commonly found in commensal and pathogenic plant-associated bacteria. Phylogenetic analysis of phytobacterial T6SS clusters shows that they are distributed in the five main clades previously described (group 1 to 5)...
October 13, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28979890/structure-based-prototype-peptides-targeting-the-pseudomonas-aeruginosa-type-vi-secretion-system-effector-as-a-novel-antibacterial-strategy
#19
Xiaopan Gao, Zhixia Mu, Bo Qin, Yicheng Sun, Sheng Cui
The type VI secretion system (T6SS) secretes numerous toxins for bacteria-bacteria competition. TplE is a newly identified trans-kingdom toxin secreted by the T6SS in Pseudomonas aeruginosa, while TplEi neutralizes the toxic effect of TplE to protect bacteria autointoxication. Blocking the interaction of TplE-TplEi could unleash the toxin, causing bacterial cell death. In this study, we applied a crystallographic approach to design a structural-based antimicrobial peptides targeting the interaction of TplE and TplEi...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28973030/cholesterol-and-host-cell-surface-proteins-contribute-to-cell-cell-fusion-induced-by-the-burkholderia-type-vi-secretion-system-5
#20
Liam Whiteley, Maria Haug, Kristina Klein, Matthias Willmann, Erwin Bohn, Salvatore Chiantia, Sandra Schwarz
Following escape into the cytoplasm of host cells, Burkholderia pseudomallei and the related species Burkholderia thailandensis employ the type VI secretion system 5 (T6SS-5) to induce plasma membrane fusion with an adjacent host cell. This process leads to the formation of multinucleated giant cells and facilitates bacterial access to an uninfected host cell in a direct manner. Despite its importance in virulence, the mechanism of the T6SS-5 and the role of host cell factors in cell-cell fusion remain elusive...
2017: PloS One
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