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Alpha toxin

Taylor S Cohen, Omari Jones-Nelson, Meghan Hotz, Lily Cheng, Lloyd S Miller, JoAnn Suzich, C Kendall Stover, Bret R Sellman
Bacterial pneumonia, such as those caused by Staphylococcus aureus, is associated with an influx of inflammatory neutrophils into the lung tissue and airways. Regulation and clearance of recruited neutrophils is essential for preventing tissue damage by "friendly fire", a responsibility of macrophages in a process called efferocytosis. We hypothesized that S. aureus impairs efferocytosis by alveolar macrophages (AMs) through the activity of the secreted virulence factor alpha toxin (AT), which has been implicated in altering the antimicrobial function of AMs...
October 14, 2016: Scientific Reports
Hui Song, Pengfei Wang, Changsheng Li, Suoyi Han, Javier Lopez-Baltazar, Xinyou Zhang, Xingjun Wang
Lipoxygenase (LOX) genes are widely distributed in plants and play crucial roles in resistance to biotic and abiotic stress. Although they have been characterized in various plants, little is known about the evolution of legume LOX genes. In this study, we identified 122 full-length LOX genes in Arachis duranensis, Arachis ipaënsis, Cajanus cajan, Cicer arietinum, Glycine max, Lotus japonicus and Medicago truncatula. In total, 64 orthologous and 36 paralogous genes were identified. The full-length, polycystin-1, lipoxygenase, alpha-toxin (PLAT) and lipoxygenase domain sequences from orthologous and paralogous genes exhibited a signature of purifying selection...
October 12, 2016: Scientific Reports
R Thuret, S Hurel, F Kleinclauss, M O Timsit
OBJECTIVES: To describe lower urinary tract symptoms (LUTS) and their management in renal transplant candidates and recipients. MATERIAL AND METHODS: Relevant publications were identified through Medline ( and Embase ( database using the following keywords, alone or in association: "transplantation", "prostate hyperplasia", "transurethral resection of prostate", "urinary incontinence", "LUTS", "pelvic floor dysfunction"...
October 7, 2016: Progrès en Urologie
Janice Crespo-Salgado, V Matti Vehaskari, Tyrus Stewart, Michael Ferris, Qiang Zhang, Guangdi Wang, Eugene E Blanchard, Christopher M Taylor, Mahmoud Kallash, Larry A Greenbaum, Diego H Aviles
BACKGROUND: End-stage renal disease (ESRD) is associated with uremia and increased systemic inflammation. Alteration of the intestinal microbiota may facilitate translocation of endotoxins into the systemic circulation leading to inflammation. We hypothesized that children with ESRD have an altered intestinal microbiota and increased serum levels of bacterially derived uremic toxins. METHODS: Four groups of subjects were recruited: peritoneal dialysis (PD), hemodialysis (HD), post-kidney transplant and healthy controls...
2016: Microbiome
P Martijn den Reijer, Marjan Sandker, Susan V Snijders, Mehri Tavakol, Antoni P A Hendrickx, Willem J B van Wamel
Currently, little is known about the in vivo human immune response against Staphylococcus aureus during a biofilm-associated infection, such as osteomyelitis, and how this relates to protein production in biofilms in vitro. Therefore, we characterized IgG responses in 10 patients with chronic osteomyelitis against 50 proteins of S. aureus, analyzed the presence of these proteins in biofilms of the infecting isolates on polystyrene (PS) and human bone in vitro, and explored the relation between in vivo and in vitro data...
September 14, 2016: Medical Microbiology and Immunology
Kai Xia, Yudong Li, Jing Sun, Xinle Liang
Acetobacter pasteurianus, an acetic acid resistant bacterium belonging to alpha-proteobacteria, has been widely used to produce vinegar in the food industry. To understand the mechanism of its high tolerance to acetic acid and robust ability of oxidizing ethanol to acetic acid (> 12%, w/v), we described the 3.1 Mb complete genome sequence (including 0.28 M plasmid sequence) with a G+C content of 52.4% of A. pasteurianus Ab3, which was isolated from the traditional Chinese rice vinegar (Meiguichu) fermentation process...
2016: PloS One
Carsten Wloka, Natalie Lisa Mutter, Misha Soskine, Giovanni Maglia
Nanopores are used in single-molecule DNA analysis and sequencing. Herein, we show that Fragaceatoxin C (FraC), an α-helical pore-forming toxin from an actinoporin protein family, can be reconstituted in sphingomyelin-free standard planar lipid bilayers. We engineered FraC for DNA analysis and show that the funnel-shaped geometry allows tight wrapping around single-stranded DNA (ssDNA), resolving between homopolymeric C, T, and A polynucleotide stretches. Remarkably, despite the 1.2 nm internal constriction of FraC, double-stranded DNA (dsDNA) can translocate through the nanopore at high applied potentials, presumably through the deformation of the α-helical transmembrane region of the pore...
September 26, 2016: Angewandte Chemie
Li Qin, Joshua W McCausland, Gordon Y C Cheung, Michael Otto
PSM-mec is a secreted virulence factor that belongs to the phenol-soluble modulin (PSM) family of amphipathic, alpha-helical peptide toxins produced by Staphylococcus species. All known PSMs are core genome-encoded with the exception of PSM-mec, whose gene is found in specific sub-types of SCCmec methicillin resistance mobile genetic elements present in methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci. In addition to the cytolytic translational product, PSM-mec, the psm-mec locus encodes a regulatory RNA...
2016: Frontiers in Microbiology
Larine Kupski, Marisa Freitas, Daniela Ribeiro, Eliana Badiale Furlong, Eduarda Fernandes
Ochratoxin A (OTA) is a mycotoxin produced by several species of fungi from the Aspergillus and Penicillium genera that frequently grow in improperly stored food products. OTA has carcinogenic, teratogenic and nephrotoxic potential and sustains a high half-life in human blood. Despite the recently efforts to decontaminate OTA through its conversion into its metabolite ochratoxin alpha (OTα), there are just a few reports in literature comparing the toxic effects of these toxins. Thus, herein we studied and compared the proinflammatory and toxicological effects of OTA and its metabolite OTα in human neutrophils in vitro...
August 10, 2016: Toxicology
B S Zhorov, D B Tikhonov
Voltage-gated sodium channels are targets for many toxins and medically important drugs. Despite decades of intensive studies in industry and academia, atomic mechanisms of action are still not completely understood. The major cause is a lack of high-resolution structures of eukaryotic channels and their complexes with ligands. In these circumstances a useful approach is homology modeling that employs as templates X-ray structures of potassium channels and prokaryotic sodium channels. On one hand, due to inherent limitations of this approach, results should be treated with caution...
2016: Current Topics in Membranes
Alexey Dementiev, Jason Board, Anand Sitaram, Timothy Hey, Matthew S Kelker, Xiaoping Xu, Yan Hu, Cristian Vidal-Quist, Vimbai Chikwana, Samantha Griffin, David McCaskill, Nick X Wang, Shao-Ching Hung, Michael K Chan, Marianne M Lee, Jessica Hughes, Alice Wegener, Raffi V Aroian, Kenneth E Narva, Colin Berry
BACKGROUND: The Cry6 family of proteins from Bacillus thuringiensis represents a group of powerful toxins with great potential for use in the control of coleopteran insects and of nematode parasites of importance to agriculture. These proteins are unrelated to other insecticidal toxins at the level of their primary sequences and the structure and function of these proteins has been poorly studied to date. This has inhibited our understanding of these toxins and their mode of action, along with our ability to manipulate the proteins to alter their activity to our advantage...
2016: BMC Biology
Shuyi Chen, Haiying Wang, Huawei Gu, Chunli Sun, Shan Li, Hanping Feng, Jufang Wang
Clostridium difficile toxin A (TcdA) and toxin B (TcdB) are the major virulence factors involved in C. difficile-associated diarrhea and pseudomembranous colitis. TcdA and TcdB both contain at least four distinct domains: the glucosyltransferase domain, cysteine protease domain, receptor binding domain, and translocation domain. Few studies have investigated the translocation domain and its mechanism of action. Recently, it was demonstrated that a segment of 97 amino acids (AA 1756-1852, designated D97) within the translocation domain of TcdB is essential for the in vitro and in vivo toxicity of TcdB...
2016: Toxins
John M Cullen, Brenda Faiola, David H Melich, Richard A Peterson, Holly L Jordan, Carie L Kimbrough, Richard T Miller
Differences in the responses of conventional and germfree male Sprague-Dawley rats to acute injury induced by alpha-naphthylisothiocyanate (ANIT), a well-characterized biliary epithelial toxicant, were evaluated. Conventional and germfree rats were dosed once orally with 50 mg/kg of ANIT or corn oil alone and serially sacrificed daily for the next 3 days. Germfree rats treated with ANIT tended to have greater increases in virtually all liver and biliary-related analytes compared with conventional rats treated with ANIT; however, significant differences were found only in a few of these analytes including increased bile acids on day 3, total bilirubin on day 4, glutamate dehydrogenase (GLDH) on day 3, and reduced paraoxonase 1 (PON1) on days 2 and 3...
October 2016: Toxicologic Pathology
Hon Wai Koon, Bowei Su, Chunlan Xu, Caroline C Mussatto, Diana Hoang-Ngoc Tran, Elaine C Lee, Christina Ortiz, Jiani Wang, Jung Eun Lee, Samantha Ho, Xinhua Chen, Ciaran P Kelly, Charalabos Pothoulakis
C. difficile infection (CDI) is a common debilitating nosocomial infection associated with high mortality. Several CDI outbreaks have been attributed to ribotypes 027, 017, and 078. Clinical and experimental evidence indicates that the nonpathogenic yeast Saccharomyces boulardii CNCM I-745 (S.b) is effective for the prevention of CDI. However, there is no current evidence suggesting this probiotic can protect from CDI caused by outbreak-associated strains. We used established hamster models infected with outbreak-associated C...
October 1, 2016: American Journal of Physiology. Gastrointestinal and Liver Physiology
Yasuyuki Noyama, Mitsuhiro Okano, Tazuko Fujiwara, Shin Kariya, Takaya Higaki, Takenori Haruna, Sei-Ichiro Makihara, Kengo Kanai, Takahisa Koyama, Masami Taniguchi, Jun-Ichi Ishitoya, Akira Kanda, Yoshiki Kobayashi, Mikiya Asako, Koichi Tomoda, Kazunori Nishizaki
BACKGROUND: IL-22 is an IL-10-family cytokine that regulates chronic inflammation. We investigated the role of IL-22 and its receptor, IL-22R1, in the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP). METHODS: IL-22 and IL-22R1 protein and mRNA expression in NP and in uncinate tissues (UT) from CRS and non-CRS patients was examined using immunohistochemistry and real-time PCR, respectively. Dispersed NP and UT cells were cultured with the Staphylococcus aureus exotoxins, staphylococcal enterotoxin B and alpha-toxin, following which exotoxin-induced IL-22 levels and their association with clinicopathological factors were analyzed...
August 5, 2016: Allergology International: Official Journal of the Japanese Society of Allergology
Ina Eiffler, Jane Behnke, Sabine Ziesemer, Christian Müller, Jan-Peter Hildebrandt
Membrane potential (Vm)-, Na(+)-, or Ca(2+)-sensitive fluorescent dyes were used to analyze changes in Vm or intracellular ion concentrations in airway epithelial cells treated with Staphylococcus aureus α-toxin (Hla), a major virulence factor of pathogenic strains of these bacteria. Gramicidin, a channel-forming peptide causing membrane permeability to monovalent cations, a mutated form of Hla, rHla-H35L, which forms oligomers in the plasma membranes of eukaryotic cells but fails to form functional transmembrane pores, or the cyclodextrin-derivative IB201, a blocker of the Hla pore, were used to investigate the permeability of the pore...
September 1, 2016: American Journal of Physiology. Lung Cellular and Molecular Physiology
Nathan C Clemons, Shuhong Luo, Mengfei Ho, Brenda A Wilson
Pasteurella multocida toxin (PMT), the major virulence factor responsible for zoonotic atrophic rhinitis, is a protein deamidase that activates the alpha subunit of heterotrimeric G proteins. Initial activation of G alpha-q-coupled phospholipase C-beta-1 signaling by PMT is followed by uncoupling of G alpha-q-dependent signaling, causing downregulation of downstream calcium and mitogenic signaling pathways. Here, we show that PMT decreases endogenous and exogenously expressed G alpha-q protein content in host cell plasma membranes and in detergent resistant membrane (DRM) fractions...
2016: Toxins
Rongfeng Li, Huahua Yu, Yang Yue, Song Liu, Ronge Xing, Xiaolin Chen, Pengcheng Li
UNLABELLED: Jellyfish sting has become a worldwide issue of critical concern to human health and safety in coastal areas in recent decades. Cyanea nozakii is one of the dominant blooming species and dangerous stingers in China. However, it remains unclear how many and what types of toxins are present in the venom. So, we used a combined transcriptomics and proteomics approach to investigate the venom composition of jellyfish C. nozakii. In total 4,608,524 Illumina valid reads were obtained to de novo assemble to 40,434 unigenes in the transcriptomics analysis...
October 4, 2016: Journal of Proteomics
Johannes Asplund-Samuelsson, John Sundh, Chris L Dupont, Andrew E Allen, John P McCrow, Narin A Celepli, Birgitta Bergman, Karolina Ininbergs, Martin Ekman
Metacaspases are distant homologs of metazoan caspase proteases, implicated in stress response, and programmed cell death (PCD) in bacteria and phytoplankton. While the few previous studies on metacaspases have relied on cultured organisms and sequenced genomes, no studies have focused on metacaspases in a natural setting. We here present data from the first microbial community-wide metacaspase survey; performed by querying metagenomic and metatranscriptomic datasets from the brackish Baltic Sea, a water body characterized by pronounced environmental gradients and periods of massive cyanobacterial blooms...
2016: Frontiers in Microbiology
Osvaldo J M Nascimento, Bruno L Pessoa, Marco Orsini, Pedro Ribeiro, Eduardo Davidovich, Camila Pupe, Pedro Moreira Filho, Ricardo Menezes Dornas, Lucas Masiero, Juliana Bittencourt, Victor Hugo Bastos
Neuropathic pain (NP) is the result of a series of conditions caused by diseases or lesions to the somatosensory system. Due to the better understanding of NP pathophysiology previously unexplored therapies have been used with encouraging results. In this group, acetyl-L-carnitine, alpha-lipoic-acid, cannabinoids, clonidine, EMA401, botulinum toxin type A and new voltage-gated sodium channel blockers, can be included. Besides, changing paradigms may occur with the advent of optogenetics and a better understanding of epigenetic regulation...
June 15, 2016: Neurology International
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