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Toxins

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https://www.readbyqxmd.com/read/28805726/chemical-identity-of-interaction-of-protein-with-reactive-metabolite-of-diosbulbin-b-in-vitro-and-in-vivo
#1
Kai Wang, Dongju Lin, Xiucai Guo, Wenlin Huang, Ying Peng, Jiang Zheng
Diosbulbin B (DIOB), a hepatotoxic furan-containing compound, is a primary ingredient in Dioscorea bulbifera L., a common herbal medicine. Metabolic activation is required for DIOB-induced liver injury. Protein covalent binding of an electrophilic reactive intermediate of DIOB is considered to be one of the key mechanisms of cytotoxicity. A bromine-based analytical technique was developed to characterize the chemical identity of interaction of protein with reactive intermediate of DIOB. Cysteine (Cys) and lysine (Lys) residues were found to react with the reactive intermediate to form three types of protein modification, including Cys adduction, Schiff's base, and Cys/Lys crosslink...
August 14, 2017: Toxins
https://www.readbyqxmd.com/read/28805686/lengths-of-the-c-terminus-and-interconnecting-loops-impact-stability-of-spider-derived-gating-modifier-toxins
#2
Akello J Agwa, Yen-Hua Huang, David J Craik, Sónia T Henriques, Christina I Schroeder
Spider gating modifier toxins (GMTs) are potent modulators of voltage-gated ion channels and have thus attracted attention as drug leads for several pathophysiological conditions. GMTs contain three disulfide bonds organized in an inhibitory cystine knot, which putatively confers them with high stability; however, thus far, there has not been a focused study to establish the stability of GMTs in physiological conditions. We examined the resistance of five GMTs including GpTx-1, HnTx-IV, HwTx-IV, PaurTx-3 and SgTx-1, to pH, thermal and proteolytic degradation...
August 12, 2017: Toxins
https://www.readbyqxmd.com/read/28800062/cellular-entry-of-clostridium-perfringens-iota-toxin-and-clostridium-botulinum-c2-toxin
#3
REVIEW
Masaya Takehara, Teruhisa Takagishi, Soshi Seike, Masataka Oda, Yoshihiko Sakaguchi, Junzo Hisatsune, Sadayuki Ochi, Keiko Kobayashi, Masahiro Nagahama
Clostridium perfringens iota-toxin and Clostridium botulinum C2 toxin are composed of two non-linked proteins, one being the enzymatic component and the other being the binding/translocation component. These latter components recognize specific receptors and oligomerize in plasma membrane lipid-rafts, mediating the uptake of the enzymatic component into the cytosol. Enzymatic components induce actin cytoskeleton disorganization through the ADP-ribosylation of actin and are responsible for cell rounding and death...
August 11, 2017: Toxins
https://www.readbyqxmd.com/read/28792467/fusarium-mycotoxins-in-swiss-wheat-a-survey-of-growers-samples-between-2007-and-2014-shows-strong-year-and-minor-geographic-effects
#4
Susanne Vogelgsang, Tomke Musa, Irene Bänziger, Andreas Kägi, Thomas D Bucheli, Felix E Wettstein, Matias Pasquali, Hans-Rudolf Forrer
To assess the occurrence of Fusarium toxins in wheat in Switzerland, an eight-year survey was conducted by analysing a total of 686 harvest samples from growers using LC-MS/MS. Between 2007 and 2010, 527 samples were obtained from 17 cantons. Between 2011 and 2014, 159 samples were collected from the canton Berne. The most frequent toxins detected were deoxynivalenol (DON), zearalenone (ZEA) and nivalenol (NIV). The overall mean DON content in all samples was 607 µg/kg, and 11% exceeded the European limit for unprocessed cereals for foodstuffs (1250 µg/kg)...
August 9, 2017: Toxins
https://www.readbyqxmd.com/read/28786958/spider-neurotoxins-short-linear-cationic-peptides-and-venom-protein-classification-improved-by-an-automated-competition-between-exhaustive-profile-hmm-classifiers
#5
Dominique Koua, Lucia Kuhn-Nentwig
Spider venoms are rich cocktails of bioactive peptides, proteins, and enzymes that are being intensively investigated over the years. In order to provide a better comprehension of that richness, we propose a three-level family classification system for spider venom components. This classification is supported by an exhaustive set of 219 new profile hidden Markov models (HMMs) able to attribute a given peptide to its precise peptide type, family, and group. The proposed classification has the advantages of being totally independent from variable spider taxonomic names and can easily evolve...
August 8, 2017: Toxins
https://www.readbyqxmd.com/read/28783135/enzymatic-and-pro-inflammatory-activities-of-bothrops-lanceolatus-venom-relevance-for-envenomation
#6
Marie Delafontaine, Isadora Maria Villas-Boas, Laurence Mathieu, Patrice Josset, Joël Blomet, Denise V Tambourgi
Bothrops lanceolatus, commonly named 'Fer-de-Lance', is an endemic snake of the French Caribbean Island of Martinique. Envenomations by B. lanceolatus present clinical aspects characterized by systemic thrombotic syndrome and important local inflammation, involving edema and pain but limited hemorrhage. To investigate mechanisms of venom-induced inflammation, B. lanceolatus venom was characterized, its cross-reactivity with bothropic antivenom explored, its cytotoxicity on human keratinocytes and vascular cells, and the production of cytokines and chemokines were analyzed...
August 7, 2017: Toxins
https://www.readbyqxmd.com/read/28783092/interaction-between-various-apple-procyanidin-and-staphylococcal-enterotoxin-a-and-their-inhibitory-effects-on-toxin-activity
#7
Yuko Shimamura, Chikako Hirai, Yuka Sugiyama, Mio Utsumi, Akio Yanagida, Masatsune Murata, Norio Ohashi, Shuichi Masuda
In this study, we investigated the interaction between apple polyphenols (AP; mainly consisting of procyanidin (PC) from an apple) and staphylococcal enterotoxin A (SEA), and the inhibitory effects of AP on SEA activity. According to the degree of polymerization, in particularly highly polymerized PC (more than pentamer) strongly interacted with SEA. The binding affinity of AP with SEA molecules was determined using Biacore analysis. AP reacted with SEA immobilized on a Biacore sensor chip. After treatment with pepsin and pancreatin, to examine the changes of binding affinity of AP in intragastric conditions, AP maintained interaction with SEA...
August 7, 2017: Toxins
https://www.readbyqxmd.com/read/28783084/enter-the-dragon-the-dynamic-and-multifunctional-evolution-of-anguimorpha-lizard-venoms
#8
Ivan Koludarov, Timothy Nw Jackson, Bianca Op den Brouw, James Dobson, Daniel Dashevsky, Kevin Arbuckle, Christofer J Clemente, Edward J Stockdale, Chip Cochran, Jordan Debono, Carson Stephens, Nadya Panagides, Bin Li, Mary-Louise Roy Manchadi, Aude Violette, Rudy Fourmy, Iwan Hendrikx, Amanda Nouwens, Judith Clements, Paolo Martelli, Hang Fai Kwok, Bryan G Fry
While snake venoms have been the subject of intense study, comparatively little work has been done on lizard venoms. In this study, we have examined the structural and functional diversification of anguimorph lizard venoms and associated toxins, and related these results to dentition and predatory ecology. Venom composition was shown to be highly variable across the 20 species of Heloderma, Lanthanotus, and Varanus included in our study. While kallikrein enzymes were ubiquitous, they were also a particularly multifunctional toxin type, with differential activities on enzyme substrates and also ability to degrade alpha or beta chains of fibrinogen that reflects structural variability...
August 6, 2017: Toxins
https://www.readbyqxmd.com/read/28777321/prevalence-and-genetic-characteristics-of-staphylococcus-aureus-and-staphylococcus-argenteus-isolates-harboring-panton-valentine-leukocidin-enterotoxins-and-tsst-1-genes-from-food-handlers-in-myanmar
#9
Meiji Soe Aung, Thida San, Mya Mya Aye, San Mya, Win Win Maw, Khin Nyein Zan, Wut Hmone Win Htut, Mitsuyo Kawaguchiya, Noriko Urushibara, Nobumichi Kobayashi
Asymptomatic carriers of toxigenic Staphylococcus aureus are potential source of diseases, including food poisoning. Toxigenic potential and genetic traits of colonizing S. aureus were investigated for 563 healthy food handlers in Myanmar. Carriage of S. aureus was found in 110 individuals (19.5%), and a total of 144 S. aureus isolates were recovered from nasal cavities (110 isolates) and hands (34 isolates). Panton-Valentine leucocidin genes (pvl) were detected in 18 isolates (12.5%), among which 11 isolates were classified into coa-VIa, agr type III, and ST1930 (CC96) that had been also detected in pvl-positive clinical isolates in Myanmar...
August 4, 2017: Toxins
https://www.readbyqxmd.com/read/28777306/sex-is-a-determinant-for-deoxynivalenol-metabolism-and-elimination-in-the-mouse
#10
James J Pestka, Erica S Clark, Heidi E Schwartz-Zimmermann, Franz Berthiller
Based on prior observations that deoxynivalenol (DON) toxicity is sex-dependent, we compared metabolism and clearance of this toxin in male and female mice. Following intraperitoneal challenge with 1 mg/kg bw DON, the dose used in the aforementioned toxicity study, ELISA and LC-MS/MS analyses revealed that by 24 h, most DON and DON metabolites were excreted via urine (49-86%) as compared to feces (1.2-8.3%). Females excreted DON and its principal metabolites (DON-3-, DON-8,15 hemiketal-8-, and iso-DON-8-glucuronides) in urine more rapidly than males...
August 4, 2017: Toxins
https://www.readbyqxmd.com/read/28767072/insights-into-the-mechanisms-involved-in-strong-hemorrhage-and-dermonecrosis-induced-by-atroxlysin-ia-a-pi-class-snake-venom-metalloproteinase
#11
Luciana Aparecida Freitas-de-Sousa, Mônica Colombini, Mônica Lopes-Ferreira, Solange M T Serrano, Ana Maria Moura-da-Silva
Hemorrhage is the most prominent effect of snake venom metalloproteinases (SVMPs) in human envenomation. The capillary injury is a multifactorial effect caused by hydrolysis of the components of the basement membrane (BM). The PI and PIII classes of SVMPs are abundant in viperid venoms and hydrolyze BM components. However, hemorrhage is associated mostly with PIII-class SVMPs that contain non-catalytic domains responsible for the binding of SVMPs to BM proteins, facilitating enzyme accumulation in the tissue and enhancing its catalytic efficiency...
August 2, 2017: Toxins
https://www.readbyqxmd.com/read/28758925/analysis-of-the-masked-metabolite-of-deoxynivalenol-and-fusarium-resistance-in-cimmyt-wheat-germplasm
#12
Hiroyuki Nakagawa, Xinyao He, Yosuke Matsuo, Pawan K Singh, Masayo Kushiro
Fusarium head blight (FHB) causes significant grain loss and contamination of grains with harmful mycotoxins, especially deoxynivalenol (DON). Fusarium resistance and DON accumulation have been extensively investigated in various cultivars; however, the level of DON-3-O-glucoside (D3G) has not been as carefully studied. In this study, we measured accumulated DON and D3G levels in CIMMYT wheat elite germplasm using an analytical method validated in-house. Co-occurring nivalenol (NIV) and ergostrerol (ERG) were also analyzed...
July 29, 2017: Toxins
https://www.readbyqxmd.com/read/28788072/the-middle-fragment-of-helicobacter-pylori-caga-induces-actin-rearrangement-and-triggers-its-own-uptake-into-gastric-epithelial-cells
#13
Abolghasem Tohidpour, Rebecca J Gorrell, Anna Roujeinikova, Terry Kwok
Cytotoxin-associated gene product A (CagA) is a major virulence factor secreted by Helicobacter pylori. CagA activity in the gastric epithelium is associated with higher risk of gastric cancer development. Bacterial type IV secretion system (T4SS)-mediated translocation of CagA into the cytosol of human epithelial cells occurs via a poorly understood mechanism that requires CagA interaction with the host membrane lipid phosphatidylserine (PS) and host cell receptor integrin α₅β₁. Here we have characterized the isolated recombinant middle fragment of CagA (CagA-M) that contains the positively-charged PS-binding region (aa 613-636) and a putative β₁ integrin binding site, but lacks the EPIYA region, secretion signal peptide and the CagA multimerization motif...
July 28, 2017: Toxins
https://www.readbyqxmd.com/read/28788055/sensitive-detection-of-%C3%AE-conotoxin-gi-in-human-plasma-using-a-solid-phase-extraction-column-and-lc-ms-ms
#14
Shuo Yu, Bo Yang, Liangping Yan, Qiuyun Dai
α-conotoxin GI, a short peptide toxin in the venom of Conus geographus, is composed of 13 amino acids and two disulfide bonds. It is the most toxic component of Conus geographus venom with estimated lethal doses of 0.029-0.038 mg/kg for humans. There is currently no reported analytical method for this toxin. In the present study, a sensitive detection method was developed to quantify GI in human plasma using a solid-phase extraction (SPE) column (polystyrene-divinyl benzene copolymer) combined with liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the multiple reaction monitoring (MRM) mode...
July 28, 2017: Toxins
https://www.readbyqxmd.com/read/28788054/bacterial-toxins-for-cancer-therapy
#15
REVIEW
Nour-Imene Zahaf, Gudula Schmidt
Several pathogenic bacteria secrete toxins to inhibit the immune system of the infected organism. Frequently, they catalyze a covalent modification of specific proteins. Thereby, they block production and/or secretion of antibodies or cytokines. Moreover, they disable migration of macrophages and disturb the barrier function of epithelia. In most cases, these toxins are extremely effective enzymes with high specificity towards their cellular substrates, which are often central signaling molecules. Moreover, they encompass the capacity to enter mammalian cells and to modify their substrates in the cytosol...
July 28, 2017: Toxins
https://www.readbyqxmd.com/read/28757599/different-metabolic-pathways-are-involved-in-response-of-saccharomyces-cerevisiae-to-l-a-and-m-viruses
#16
Juliana Lukša, Bazilė Ravoitytė, Aleksandras Konovalovas, Lina Aitmanaitė, Anzhelika Butenko, Vyacheslav Yurchenko, Saulius Serva, Elena Servienė
Competitive and naturally occurring yeast killer phenotype is governed by coinfection with dsRNA viruses. Long-term relationship between the host cell and viruses appear to be beneficial and co-adaptive; however, the impact of viral dsRNA on the host gene expression has barely been investigated. Here, we determined the transcriptomic profiles of the host Saccharomyces cerevisiae upon the loss of the M-2 dsRNA alone and the M-2 along with the L-A-lus dsRNAs. We provide a comprehensive study based on the high-throughput RNA-Seq data, Gene Ontology and the analysis of the interaction networks...
July 25, 2017: Toxins
https://www.readbyqxmd.com/read/28737735/the-putative-histone-methyltransferase-dot1-regulates-aflatoxin-and-pathogenicity-attributes-in-aspergillus-flavus
#17
Linlin Liang, Yinghang Liu, Kunlong Yang, Guinan Lin, Zhangling Xu, Huahui Lan, Xiuna Wang, Shihua Wang
Lysine methyltransferases transfer methyl groups in specific lysine sites, which regulates a variety of important biological processes in eukaryotes. In this study, we characterized a novel homolog of the yeast methyltransferase DOT1 in A. flavus, and observed the roles of dot1 in A. flavus. Deletion of dot1 showed a significant decrease in conidiation, but an increase in sclerotia formation. A change in viability to multiple stresses was also found in the Δdot1 mutant. Additionally, aflatoxin (AF) production was found severely impaired in the Δdot1 mutant...
July 24, 2017: Toxins
https://www.readbyqxmd.com/read/28737685/microcystin-prevalence-throughout-lentic-waterbodies-in-coastal-southern-california
#18
Meredith D A Howard, Carey Nagoda, Raphael M Kudela, Kendra Hayashi, Avery Tatters, David A Caron, Lilian Busse, Jeff Brown, Martha Sutula, Eric D Stein
Toxin producing cyanobacterial blooms have increased globally in recent decades in both frequency and intensity. Despite the recognition of this growing risk, the extent and magnitude of cyanobacterial blooms and cyanotoxin prevalence is poorly characterized in the heavily populated region of southern California. Recent assessments of lentic waterbodies (depressional wetlands, lakes, reservoirs and coastal lagoons) determined the prevalence of microcystins and, in some cases, additional cyanotoxins. Microcystins were present in all waterbody types surveyed although toxin concentrations were generally low across most habitats, as only a small number of sites exceeded California's recreational health thresholds for acute toxicity...
July 22, 2017: Toxins
https://www.readbyqxmd.com/read/28726719/sima-cells-for-a-serotype-specific-and-sensitive-cell-based-neutralization-test-for-botulinum-toxin-a-and-e
#19
Nicola Bak, Shalini Rajagopal, Paul Stickings, Dorothea Sesardic
Botulinum toxins (BoNTs), of which there are seven serotypes, are among the most potent neurotoxins, with serotypes A, B and E causing human botulism. Antitoxins form the first line of treatment for botulism, and functional, highly sensitive in vitro methods for toxin neutralization are needed to replace the current in vivo methods used for determination of antitoxin potency. In this preliminary proof of concept study, we report the development of a neutralization test using the neuroblastoma SiMa cell line...
July 20, 2017: Toxins
https://www.readbyqxmd.com/read/28753957/the-uremic-toxin-indoxyl-sulfate-accelerates-thrombotic-response-after-vascular-injury-in-animal-models
#20
Malgorzata Karbowska, Tomasz W Kaminski, Natalia Marcinczyk, Tomasz Misztal, Tomasz Rusak, Lukasz Smyk, Dariusz Pawlak
Chronic kidney disease (CKD) patients are at high risk for thrombotic events. Indoxyl sulfate (IS) is one of the most potent uremic toxins that accumulates during CKD. Even though IS is associated with an increased risk for cardiovascular disease, its impact on thrombotic events still remains not fully understood. The purpose of the study was to evaluate the direct effect of IS on thrombotic process. We examined the impact of acute exposure to IS on thrombus development induced by electric current in Wistar rats, intravital thrombus formation after laser-induced injury in the mice endothelium, coagulation profile, clot formation dynamics, platelet aggregations, and erythrocyte osmotic resistance...
July 19, 2017: Toxins
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