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Doreen Baumann, Helen Salia, Lilo Greune, Stephanie Norkowski, Britta Körner, Zina M Uckeley, Gad Frankel, Marianne Guenot, Christian Rüter, M Alexander Schmidt
Enteropathogenic Escherichia coli (EPEC) subvert host cell signaling pathways by injecting effector proteins via a Type 3 Secretion System (T3SS). The T3SS-dependent EspB protein is a multi-functional effector protein, which contributes to adherence and translocator pore formation and after injection exhibits several intracellular activities. In addition, EspB is also secreted into the environment. Effects of secreted EspB have not been reported thus far. As a surrogate for secreted EspB we employed recombinant EspB (rEspB) derived from the prototype EPEC strain E2348/69 and investigated the interactions of the purified protein with different human epithelial and immune cells including monocytic THP-1 cells, macrophages, dendritic cells, U-937, epithelial T84, Caco-2, and HeLa cells...
March 12, 2018: International Journal of Medical Microbiology: IJMM
Kaiyi Zhang, Ambre Riba, Monika Nietschke, Natalia Torow, Urska Repnik, Andreas Pütz, Marcus Fulde, Aline Dupont, Michael Hensel, Mathias Hornef
Effector molecules translocated by the Salmonella pathogenicity island (SPI)1-encoded type 3 secretion system (T3SS) critically contribute to the pathogenesis of human Salmonella infection. They facilitate internalization by non-phagocytic enterocytes rendering the intestinal epithelium an entry site for infection. Their function in vivo has remained ill-defined due to the lack of a suitable animal model that allows visualization of intraepithelial Salmonella. Here, we took advantage of our novel neonatal mouse model and analyzed various bacterial mutants and reporter strains as well as gene deficient mice...
March 9, 2018: PLoS Pathogens
Victoria Hritonenko, Matteo Metruccio, David Evans, Suzanne Fleiszig
The type three secretion system (T3SS) is important for the intracellular survival of Pseudomonas aeruginosa. Known T3SS inducers include low Ca2+, serum, or host cell contact. Here, we used corneal epithelial cell lysates to test if host cytosolic factors could also induce the T3SS. Invasive P. aeruginosa strain PAO1 was exposed to cell lysates for 16 h, and expression of T3SS effectors determined by q-PCR and Western immunoblot. Lysate exposure reduced PAO1 growth (∼5-fold) versus trypticase soy broth (TSB), but also resulted in appearance of a protein in culture supernatants, but not bacteria cell pellets, that reacted with antibody raised against ExoS...
March 6, 2018: FEMS Microbiology Letters
Xiaodong Liu, Yantao Luo, Zhefei Li, Gehong Wei
Mesorhizobium alhagi CCNWXJ12-2T , isolated from root nodules of the desert plant Alhagi sparsifolia , contains two type III secretion systems (T3SSs). T3SSs are specialized machinery with wide distribution in bacteria that inject effector proteins into target cells. Our previous study showed that the expression of M. alhagi T3SS1 is upregulated in high-salt conditions. Here, phylogenetic analysis of T3SS1 using the core protein RhcU suggested that T3SS1 belongs to the α-Rhc II subgroup of the Rhc T3SS family...
2018: Frontiers in Microbiology
Cameron S Runte, Umang Jain, Landon J Getz, Sabrina Secord, Asaomi Kuwae, Akio Abe, Jason J LeBlanc, Andrew W Stadnyk, James B Kaper, Anne-Marie Hansen, Nikhil A Thomas
Enteropathogenic Escherichia coli (EPEC) use a type 3 secretion system (T3SS) for injection of effectors into host cells and intestinal colonization. Here, we demonstrate that the multicargo chaperone CesT has two strictly conserved tyrosine phosphosites, Y152 and Y153, that regulate differential effector secretion in EPEC. Conservative substitution of both tyrosine residues to phenylalanine strongly attenuated EPEC type 3 effector injection into host cells, and limited Tir effector mediated intimate adherence during infection...
March 6, 2018: Molecular Microbiology
Max Teplitski, Marcos de Moraes
Outbreaks of gastrointestinal illness, linked to the consumption of fruits, vegetables, and sprouts, continue to capture the attention of the general public and scientists. The recurrence of these outbreaks, despite heightened producer and consumer awareness, combined with improved sanitation protocols and technology, can be explained by the hypothesis that enteric pathogens, such as nontyphoidal Salmonella spp. and enterovirulent Escherichia coli, have evolved to exploit plants as alternative hosts. This review explores the genetic and genomic context for this hypothesis...
March 1, 2018: Trends in Microbiology
Colin D Robertson, Tracy H Hazen, James B Kaper, David A Rasko, Anne-Marie Hansen
Enteric pathogens with low infectious doses rely on the ability to orchestrate the expression of virulence and metabolism-associated genes in response to environmental cues for successful infection. Accordingly, the human pathogen enterohemorrhagic Escherichia coli (EHEC) employs a complex multifaceted regulatory network to link the expression of type III secretion system (T3SS) components to nutrient availability. While phosphorylation of histidine and aspartate residues on two-component system response regulators is recognized as an integral part of bacterial signaling, the involvement of phosphotyrosine-mediated control is minimally explored in Gram-negative pathogens...
February 27, 2018: MBio
Laurie Pinaud, Philippe J Sansonetti, Armelle Phalipon
Microbial pathogens possess a diversity of weapons that disrupt host homeostasis and immune defenses, thus resulting in the establishment of infection. The best-characterized system mediating bacterial protein delivery into target eukaryotic cells is the type III secretion system (T3SS) expressed by Gram-negative bacteria, including the human enteric pathogens Shigella, Salmonella, Yersinia, and enteropathogenic/enterohemorragic Escherichia coli (EPEC/EHEC). The emerging global view is that these T3SS-bearing pathogens share similarities in their ability to target key cellular pathways such as the cell cytoskeleton, trafficking, cell death/survival, and the NF-κB and MAPK signaling pathways...
February 21, 2018: Trends in Microbiology
Carlos R Osorio
No abstract text is available yet for this article.
February 22, 2018: Virulence
Caetanie F Tchagang, Renlin Xu, Cyr Lézin Doumbou, James T Tambong
Multilocus sequence analysis (MLSA) of two new biological control strains (S1E40 and S3E12) of Pseudomonas was performed to assess their taxonomic position relative to close lineages, and comparative genomics employed to investigate whether these strains differ in key genetic features involved in hypersensitivity responses (HRs). Strain S3E12, at high concentration, incites HRs on tobacco and corn plantlets while S1E40 does not. Phylogenies based on individual genes and 16S rRNA-gyrB-rpoB-rpoD concatenated sequence data show strains S1E40 and S3E12 clustering in distinct groups...
February 21, 2018: MicrobiologyOpen
Laurence Don Wai Luu, Sophie Octavia, Ling Zhong, Mark Raftery, Vitali Sintchenko, Ruiting Lan
Bordetella pertussis causes whooping cough. The predominant strains in Australia changed to single nucleotide polymorphism (SNP) cluster I (pertussis toxin promoter allele ptxP3/pertactin gene allele prn2) from cluster II (non-ptxP3/non-prn2). Cluster I were mostly responsible for the 2008-2012 Australian epidemic and were found to have higher fitness compared to cluster II using an in vivo mouse competition assay, regardless of host's immunisation status. This study aimed to identify proteomic differences that explain higher fitness in cluster I using iTRAQ, and high-resolution multiple reaction monitoring (MRM-hr)...
February 21, 2018: Proteomics
Kayley H Janssen, Manisha R Diaz, Matthew Golden, Justin W Graham, Wes Sanders, Matthew C Wolfgang, Timothy L Yahr
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen with distinct acute and chronic virulence phenotypes. Whereas acute virulence is typically associated with expression of a type III secretion system (T3SS), chronic virulence is characterized by biofilm formation. Many of the phenotypes associated with acute and chronic virulence are inversely regulated by RsmA and RsmF. RsmA and RsmF are both members of the CsrA family of RNA-binding proteins and regulate protein synthesis at the post-transcriptional level...
February 20, 2018: Journal of Bacteriology
Yongjun Tang, Zeeshan Ali, Jianguo Dai, Xiaolong Liu, Yanqi Wu, Zhu Chen, Nongyue He, Song Li, Lijun Wang
Pseudomonas aeruginosa exoS gene contains important replacement (non-synonymous) single-nucleotide polymorphism (SNP) loci, of which mutations in loci 162 (G162A) and 434 (G434C) in exoS greatly affects virulence. The present study aimed to develop an SNP-based classification method for exoS loci (G162A and G434C), using magnetic enrichment polymerase chain reaction, magnetic separation, and dual-color fluorescence to provide a technical basis for understanding the T3SS genotypic variation. The two SNP loci in 3 P...
January 1, 2018: Journal of Biomedical Nanotechnology
Huanying Pang, Mingsheng Qiu, Jingmin Zhao, Rowena Hoare, Sean J Monaghan, Dawei Song, Yunsheng Chang, Jichang Jian
Vibrio alginolyticus, a bacterial pathogen in fish and humans, expresses a type III secretion system (T3SS) that is critical for pathogen virulence and disease development. However, little is known about the associated effectors (T3SEs) and their physiological role. In this study, the T3SE gene hopPmaJ (hop) was cloned from V. alginolyticus wild-type strain HY9901 and the mutant strain HY9901Δhop was constructed by the in-frame deletion method. The results showed that the deduced amino acid sequence of V. alginolyticus HopPmaJ shared 78-98% homology with other Vibrio spp...
February 7, 2018: Fish & Shellfish Immunology
A Edrees, H Abdelhamed, S W Nho, S B Park, A Karsi, F W Austin, M Essa, T Pechan, M L Lawrence
Catfish is the largest aquaculture industry in the United States. Edwardsiellosis is considered one of the most significant problems affecting this industry. Edwardsiella piscicida is a newly described species within the genus Edwardsiella, and it was previously classified as Edwardsiella tarda. It causes gastrointestinal septicaemia, primarily in summer months, in farmed channel catfish in the south-eastern United States. In the current study, we adapted gene deletion methods used for Edwardsiella to E. piscicida strain C07-087, which was isolated from a disease outbreak in a catfish production pond...
February 9, 2018: Journal of Fish Diseases
Fang Bai, Zhenpeng Li, Akihiro Umezawa, Naohiro Terada, Shouguang Jin
A protein delivery tool based on bacterial type III secretion system (T3SS) has been broadly applied in biomedical researches. In this review, we summarize various applications of the T3SS-mediate protein delivery which enables translocation of proteins directly into mammalian cells without protein purification. Some of the remarkable advancements include delivery of antigens for therapeutic vaccines, nucleases for genome editing, transcription factors for cellular reprogramming and stem cells differentiation, and signaling molecules for post-translational proteomics studies...
February 2, 2018: Biotechnology Advances
Laurent Dortet, Charlotte Lombardi, François Cretin, Andréa Dessen, Alain Filloux
Recent studies highlight that bacterial pathogens can reprogram target cells by influencing epigenetic factors. The type III secretion system (T3SS) is a bacterial nanomachine that resembles a syringe on the bacterial surface. The T3SS 'needle' delivers translocon proteins into eukaryotic cell membranes, subsequently allowing injection of bacterial effectors into the cytosol. Here we show that Pseudomonas aeruginosa induces early T3SS-dependent dephosphorylation and deacetylation of histone H3 in eukaryotic cells...
February 5, 2018: Nature Microbiology
Xiaochen Yuan, Fang Tian, Chenyang He, Geoffrey B Severin, Christopher M Waters, Quan Zeng, Fengquan Liu, Ching-Hong Yang
Dickeya dadantii 3937 secretes pectate lyases (Pels) to degrade the plant cell wall. Previously, we have demonstrated that EGcpB and EcpC function as cyclic-di-GMP (c-di-GMP) specific phosphodiesterases (PDEs) to positively regulate Pel production. However, the diguanylate cyclase (DGC) responsible for the synthesis of c-di-GMP and dichotomously regulation of Pel has remained a mystery. Here, we identified GcpA is the dominant DGC to negatively regulate Pel production by specifically repressing pelD gene expression...
February 1, 2018: Molecular Plant Pathology
Jesse R Grenz, Jessica E Cott Chubiz, Pariyamon Thaprawat, James M Slauch
The Salmonella Type Three Secretion System (T3SS), encoded in the Salmonella Pathogenicity Island 1 (SPI1) locus, mediates the invasion of the host intestinal epithelium. SPI1 expression is dependent upon three AraC-like regulators: HilD, HilC, and RtsA. These regulators act in a complex feed-forward loop to activate each other and hilA, which encodes the activator of the T3SS structural genes. HilD has been shown to be the major integration point of most signals known to activate the expression of the SPI1 T3SS, acting as a switch to control induction of the system...
January 29, 2018: Journal of Bacteriology
Yong Zhang, Jiaman Li, Weiqi Zhang, Hualei Shi, Feng Luo, Yasufumi Hikichi, Xiaojun Shi, Kouhei Ohnishi
LysR-type transcriptional regulators (LTTRs) are ubiquitous and abundant among bacteria and control a variety of cellular processes. Here, we investigated the effect of Rsc1880 (a putative LTTR, hereafter designated PrhO) on pathogenicity of Ralstonia solanacearum. Deletion of prhO substantially reduced the expression of type III secretion system (T3SS) both in vitro and in planta, and resulted in significantly impaired virulence in tomato and tobacco plants. Complementary prhO completely restored the reduced virulence and T3SS expression to that of wild type...
January 24, 2018: Molecular Plant Pathology
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