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Type 6 secretion system

Gang Li, Mengyu Shen, Shuai Le, Yinling Tan, Ming Li, Xia Zhao, Wei Shen, Yuhui Yang, Jing Wang, Hongbin Zhu, Shu Li, Xiancai Rao, Fuquan Hu, Shuguang Lu
As a third-generation sequencing method, single-molecule real-time (SMRT) technology provides long read length, and it is well suited for re-sequencing projects and de novo assembly. In this study, Pseudomonas aeruginosa PA1 was characterized and re-sequenced using SMRT technology. PA1 was also subjected to genomic, comparative, and pan-genomic analyses. The multi-drug resistant strain PA1 possesses a 6,498,072 bp genome and a sequence type of ST-782. The genome of PA1 was also visualized, and the results revealed the details of general genome annotations, virulence factors, regulatory proteins, secretion system proteins, type II toxin-antitoxin pairs, and genomic islands...
October 20, 2016: Bioscience Reports
Matthew Gordon Varga, Maria Blanca Piazuelo, Judith Romero-Gallo, Alberto G Delgado, Giovanni Suarez, Morgan E Whitaker, Uma S Krishna, Rachna V Patel, Eric P Skaar, Keith T Wilson, Holly M Scott Algood, Richard M Peek
Helicobacter pylori induces chronic gastritis in humans and infection can persist for decades. One H. pylori strain-specific constituent that augments disease risk is the cag pathogenicity island. The cag island encodes a type IV secretion system (T4SS) that translocates DNA into host cells. Toll-like receptor 9 (TLR9) is an innate immune receptor that detects hypo-methylated CpG DNA motifs. In this study, we sought to define the role of the H. pylori cag T4SS on TLR9-mediated responses in vivo H. pylori strain PMSS1 or its cagE(-) mutant, which fails to assemble a T4SS, were used to infect wild-type or Tlr9(-/-) C57BL/6 mice...
October 6, 2016: American Journal of Physiology. Gastrointestinal and Liver Physiology
Du Toit Loots, Conrad C Swanepoel, Mae Newton-Foot, Nicolaas C Gey van Pittius
The ESX-1 gene cluster, encoding the Type-VII secretion (T7S) system and its virulence associated proteins, ESAT-6 and CFP-10, is thought to be responsible for the transport of extracellular proteins across the hydrophobic and highly impermeable, cell envelope of Mycobacterium, and is involved in virulence in Mycobacterium tuberculosis, the causative agent of tuberculosis. Using a GCxGC-TOFMS metabolomics approach, a M. smegmatis ESX-1 knock-out strain (ΔESX-1ms) was compared to that of the M. smegmatis wild-type parent strain, and the metabolite markers due to the presence or absence of the ESX-1 gene cluster were identified...
October 12, 2016: Microbial Pathogenesis
Tian-Nyu Wang, Min Zhao
Laccases are green oxidases with a number of potential industrial applications. In this study, recombinant Bacillus subtilis CotA laccase was secreted by Escherichia coli via both the α-hemolysin secretion system and the YebF secretion system after microaerobic induction. Meanwhile, we discovered a much simpler approach for extracellular production of recombinant CotA laccase from E. coli, involving alternation of induction conditions to release recombinant CotA following intracellular expression. By optimizing the induction parameters, the extracellular yield of recombinant CotA laccase was improved from 157...
October 13, 2016: Applied Microbiology and Biotechnology
Satyavrata Samavedi, Patricia Diaz-Rodriguez, Joshua Dean Erndt-Marino, Mariah Hahn
The goal of the present study was to develop a fully 3D co-culture system that would allow for systematic investigation of the interplay between activated macrophages and chondrocytes in osteoarthritic disease progression. Toward this end, our 3D co-culture system was first validated against existing in vitro osteoarthritis models, which have generally cultured healthy normal chondrocytes (NCs) ─ in 2D or 3D ─ with 2D classically activated macrophages (AMs). In the current work, NCs and AMs were both encapsulated within poly(ethylene glycol) diacrylate hydrogels to better mimic the native 3D environments of both cell types within the osteoarthritic joint...
October 13, 2016: Tissue Engineering. Part A
Sanna Koskiniemi, Johan Elf
Bacteria use type 6 secretion systems in antagonistic behavior to compete for resources with other bacteria. In a recent issue of Cell, Vettiger and Basler (2016) show that bacteria can also use these systems to arm neighboring cells and force them to pass on a signal in the bacterial population.
October 10, 2016: Developmental Cell
Xiaolu Xiong, Jun Jiao, Anthony E Gregory, Pengcheng Wang, Yujing Bi, Xiaoyi Wang, Yongqiang Jiang, Bohai Wen, Daniel A Portnoy, James E Samuel, Chen Chen
Coxiella burnetii is a Gram-negative bacterium that causes acute and chronic Q fever. Due to the severe adverse effect of whole cell vaccination, identification of immunodominant antigens of C. burnetii has become a major focus of Q fever vaccine development. We hypothesized that secreted C. burnetii Type IV secretion system (T4SS) effectors may represent a major class of CD8(+) T cell antigens due to their cytosolic localization. Twenty-nine peptides were identified that elicited robust CD8(+) T cell IFN-γ recall responses from mice infected with C...
October 4, 2016: Journal of Infectious Diseases
Blake J Cochran, Liming Hou, Anil Paul Chirackal Manavalan, Benjamin M Moore, Fatiha Tabet, Afroza Sultana, Luisa Cuesta Torres, Shudi Tang, Sudichhya Shrestha, Praween Senanayake, Mili Patel, William J Ryder, Andre Bongers, Marie Maraninchi, Valerie C Wasinger, Marit Westerterp, Alan R Tall, Philip J Barter, Kerry-Anne Rye
Elevated pancreatic β-cell cholesterol levels impair insulin secretion and reduce plasma insulin levels. This study establishes that low plasma insulin levels have a detrimental effect on two major insulin target tissues: adipose tissue and skeletal muscle. Mice with increased β-cell cholesterol levels were generated by conditional deletion of the ATP binding cassette transporters, ABCA1 and ABCG1, in β-cells (β-DKO mice). Insulin secretion was impaired in these mice under basal and high glucose conditions and glucose disposal was shifted from skeletal muscle to adipose tissue...
October 4, 2016: Diabetes
Tao Geng, Ding-Ding Lv, Yu-Xia Huang, Cheng-Xiang Hou, Guang-Xing Qin, Xi-Jie Guo
Innate immunity was critical in insects defensive system and able to be induced by Janus kinase / signal transducer and activator of transcription cascade transduction (JAK/STAT) signaling pathway. Currently, it had been identified many JAK/STAT signaling pathway-related genes in silkworm, but little function was known on insect innate immunity. To explore the roles of JAK/STAT pathway in antifungal immune response in silkworm (Bombyx mori) against Beauveria bassiana infection, the expression patterns of B...
September 28, 2016: Gene
Ying Li, Sanjie Cao, Luhua Zhang, Jianlin Yuan, Gee W Lau, Yiping Wen, Rui Wu, Qin Zhao, Xiaobo Huang, Qigui Yan, Yong Huang, Xintian Wen
Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a major cause of economic loss in swine industry worldwide. TolC, the key component of multidrug efflux pumps and type I secretion systems, has been well-studied as an exit duct for numerous substances in many Gram-negative bacteria. By contrast, little is known on the role of TolC in biofilm formation. In this study, a ΔtolC mutant was used to examine the importance of TolC in biofilm formation of A. pleuropneumoniae...
2016: PloS One
Christopher D A Rodrigues, Xavier Henry, Emmanuelle Neumann, Vilius Kurauskas, Laure Bellard, Yann Fichou, Paul Schanda, Guy Schoehn, David Z Rudner, Cecile Morlot
During spore formation in Bacillus subtilis a transenvelope complex is assembled across the double membrane that separates the mother cell and forespore. This complex (called the "A-Q complex") is required to maintain forespore development and is composed of proteins with remote homology to components of type II, III, and IV secretion systems found in Gram-negative bacteria. Here, we show that one of these proteins, SpoIIIAG, which has remote homology to ring-forming proteins found in type III secretion systems, assembles into an oligomeric ring in the periplasmic-like space between the two membranes...
October 11, 2016: Proceedings of the National Academy of Sciences of the United States of America
Michal Ucko, Angelo Colorni, Lidiya Dubytska, Ronald L Thune
An Edwardsiella sp. was isolated from the kidney of diseased groupers (Epinephelus aeneus and E. marginatus) cultured in Eilat (Israel, Red Sea). Affected fish presented a severe suppurative nephritis with large abscesses occasionally spreading into the surrounding musculature. Biochemical profiles and phenotypic comparisons failed to provide a clear identification to the species level, and genetic analysis of the 16S subunit failed to discriminate between Edwardsiella piscicida, E. tarda and E. ictaluri. Analysis of the gyrB gene, however, placed the grouper isolates into the E...
September 26, 2016: Diseases of Aquatic Organisms
Diane E Griffin, Victoria K Baxter
Infection of mice with Sindbis virus (SINV) produces encephalomyelitis and provides a model for examination of the central nervous system (CNS) immune response to alphavirus infection. Clearance of infectious virus is accomplished through a cooperative effort between SINV-specific antibody and interferon gamma (IFN-γ), but the regulatory interactions are poorly understood. To determine the effects of IFN-γ on clinical disease and the antiviral immune response, C57BL/6 mice lacking IFN-γ (Ifng-/-) or IFN-γ receptor (Ifngr1-/-) were studied in comparison to wild-type (WT) mice...
September 22, 2016: Journal of General Virology
Kosha Mehta, Mark Busbridge, Derek Renshaw, Robert W Evans, Sebastien Farnaud, Vinood B Patel
Hepcidin is the key regulator of systemic iron homeostasis. The iron-sensing mechanisms and the role of intracellular iron in modulating hepatic hepcidin secretion are unclear. Therefore, we created a novel cell line, recombinant-TfR1 HepG2, expressing iron-response-element-independent TFRC mRNA to promote cellular iron-overload and examined the effect of excess holotransferrin (5g/L) on cell-surface TfR1, iron content, hepcidin secretion and mRNA expressions of TFRC, HAMP, SLC40A1, HFE and TFR2. Results showed that the recombinant cells exceeded levels of cell-surface TfR1 in wild-type cells under basal (2...
October 2016: Blood Cells, Molecules & Diseases
Matthias I Gröschel, Fadel Sayes, Roxane Simeone, Laleh Majlessi, Roland Brosch
Mycobacterium tuberculosis uses sophisticated secretion systems, named 6 kDa early secretory antigenic target (ESAT6) protein family secretion (ESX) systems (also known as type VII secretion systems), to export a set of effector proteins that helps the pathogen to resist or evade the host immune response. Since the discovery of the esx loci during the M. tuberculosis H37Rv genome project, structural biology, cell biology and evolutionary analyses have advanced our knowledge of the function of these systems...
November 2016: Nature Reviews. Microbiology
Casey J Holmes, Jennifer K Plichta, Richard L Gamelli, Katherine A Radek
Burn wound healing complications, such as graft failure or infection, are a major source of morbidity and mortality in burn patients. The mechanisms by which local burn injury alters epidermal barrier function in autologous donor skin and surrounding burn margin are largely undefined. We hypothesized that defects in the epidermal cholinergic system may impair epidermal barrier function and innate immune responses. The objective was to identify alterations in the epidermal cholinergic pathway, and their downstream targets, associated with inflammation and cell death...
September 19, 2016: Shock
Jasmine N Stannard, Tamra J Reed, Emily Myers, Lori Lowe, Mrinal K Sarkar, Xianying Xing, Johann E Gudjonsson, J Michelle Kahlenberg
Cutaneous lupus erythematosus (CLE) is a disfiguring and common manifestation in systemic lupus erythematosus (SLE), and the etiology of this predisposition for cutaneous inflammation is unknown. Here, we sought to examine the keratinocyte as an important source of IL-6 and define the mechanism for its increased production in CLE. Evaluation of discoid and subacute cutaneous lupus erythematosus lesions revealed significant epidermal upregulation of IL-6 when compared with control via real-time PCR and immunohistochemistry...
September 16, 2016: Journal of Investigative Dermatology
Michael Eschbaumer, Carolina Stenfeldt, Steven I Rekant, Juan M Pacheco, Ethan J Hartwig, George R Smoliga, Mary A Kenney, William T Golde, Luis L Rodriguez, Jonathan Arzt
BACKGROUND: In order to investigate host factors associated with the establishment of persistent foot-and-mouth disease virus (FMDV) infection, the systemic response to vaccination and challenge was studied in 47 steers. Eighteen steers that had received a recombinant FMDV A vaccine 2 weeks earlier and 29 non-vaccinated steers were challenged by intra-nasopharyngeal deposition of FMDV A24. For up to 35 days after challenge, host factors including complete blood counts with T lymphocyte subsets, type I/III interferon (IFN) activity, neutralizing and total FMDV-specific antibody titers in serum, as well as antibody-secreting cells (in 6 non-vaccinated animals) were characterized in the context of viral infection dynamics...
2016: BMC Veterinary Research
Thomas Joseph Long, Patrick A Cosgrove, Robert T Dunn, Donna B Stolz, Hisham K Hamadeh, Cynthia Afshari, Helen McBride, Linda G Griffith
Traditional in vitro human liver cell culture models lose key hepatic functions such as metabolic activity during short-term culture. Advanced 3D liver co-culture platforms offer the potential for extended hepatocyte functionality, allowing for the study of more complex biological interactions that can improve and refine human drug safety evaluation. Here, we utilize a perfusion flow 3D microreactor platform for the co-culture of cryopreserved primary human hepatocytes and Kupffer cells to study the regulation of CYP3A4 activity by chronic IL-6-mediated inflammation over two weeks...
September 12, 2016: Drug Metabolism and Disposition: the Biological Fate of Chemicals
Weiliang Chen, Tongliang Xia, Donghai Wang, Bin Huang, Peng Zhao, Jian Wang, Xun Qu, Xingang Li
The brain microenvironment has emerged as an important component in malignant progression of human glioma. However, astrocytes, the most abundant glial cells in the glioma microenvironment, have as yet a poorly defined role in the development of this disease, particularly with regard to invasion. Here, we co-cultured human astrocytes with human glioma cell lines, U251 and A172, in an in vitro transwell system in order to ascertain their influence on migration and invasion of gliomas. mRNA and protein expression assays were subsequently used to identify candidate proteins mediating this activity...
August 23, 2016: Oncotarget
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