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https://www.readbyqxmd.com/read/28334932/ribosome-dependent-vibrio-cholerae-mrnase-higb2-is-regulated-by-a-%C3%AE-strand-sliding-mechanism
#1
San Hadži, Abel Garcia-Pino, Sarah Haesaerts, Dukas Jurenas, Kenn Gerdes, Jurij Lah, Remy Loris
Toxin-antitoxin (TA) modules are small operons involved in bacterial stress response and persistence. higBA operons form a family of TA modules with an inverted gene organization and a toxin belonging to the RelE/ParE superfamily. Here, we present the crystal structures of chromosomally encoded Vibrio cholerae antitoxin (VcHigA2), toxin (VcHigB2) and their complex, which show significant differences in structure and mechanisms of function compared to the higBA module from plasmid Rts1, the defining member of the family...
February 28, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28330277/classical-and-bayesian-predictions-applied-to-bacillus-toxin-production
#2
Karim Ennouri, Rayda Ben Ayed, Maura Mazzarello, Ennio Ottaviani, Fathi Hertelli, Hichem Azzouz
Bacillus thuringiensis is a bacterium with unusual properties that make it useful for pest control in ecoagriculture. It can form a parasporal crystal containing polypeptides (also called delta-endotoxins). These entomopathogenic toxins are made during the stationary phase of the bacterial growth cycle and were initially characterized as an insect pathogen. Nowadays, the use of saturated two-level designs is very popular. This method is especially used in industrial applications where the cost of experiments is expensive...
December 2016: 3 Biotech
https://www.readbyqxmd.com/read/28298445/the-structure-and-function-of-mycobacterium-tuberculosis-mazf-mt6-provides-insights-into-conserved-features-of-mazf-endonucleases
#3
Eric D Hoffer, Stacey J Miles, Christine M Dunham
Toxin-antitoxin systems are ubiquitous in prokaryotic and archaea genomes and regulate growth in response to stress. E. coli contains at least 36 putative toxin-antitoxin gene pairs, and some pathogens such as Mycobacterium tuberculosis (Mtb) have over 90 toxin-antitoxin operons. E. coli MazF cleaves free mRNA after encountering stress and nine Mtb MazF family members cleave mRNA, tRNA, or rRNA. Moreover, Mtb MazF-mt6 cleaves 23S rRNA Helix 70 to inhibit protein synthesis. The overall tertiary folds of these MazFs are predicted to be similar, therefore it is unclear how they recognize structurally distinct RNAs...
March 15, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28292241/microbial-pest-control-agents-are-they-a-specific-and-safe-tool-for-insect-pest-management
#4
Caroline Deshayes, Myriam Siegwart, David Pauron, Josy-Anne Froger, Bruno Lapied, Véronique Apaire-Marchais
Microorganisms (viruses, bacteria and fungi) or their bioactive agents can be used as active substances and therefore are referred as Microbial Pest Control Agents (MPCA). They are used as alternative strategies to chemical insecticides to counteract the development of resistances and to reduce adverse effects on both environment and human health. These natural entomopathogenic agents, which have specific modes of action, are generally considered safer as compared to conventional chemical insecticides. Baculoviruses are the only viruses being used as the safest biological control agents...
March 14, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28282927/in-vivo-crystallization-of-three-domain-cry-toxins
#5
REVIEW
Rooma Adalat, Faiza Saleem, Neil Crickmore, Shagufta Naz, Abdul Rauf Shakoori
Bacillus thuringiensis (Bt) is the most successful, environmentally-friendly, and intensively studied microbial insecticide. The major characteristic of Bt is the production of proteinaceous crystals containing toxins with specific activity against many pests including dipteran, lepidopteran, and coleopteran insects, as well as nematodes, protozoa, flukes, and mites. These crystals allow large quantities of the protein toxins to remain stable in the environment until ingested by a susceptible host. It has been previously established that 135 kDa Cry proteins have a crystallization domain at their C-terminal end...
March 9, 2017: Toxins
https://www.readbyqxmd.com/read/28282873/crystal-structure-of-the-receptor-binding-domain-of-botulinum-neurotoxin-type-ha-also-known-as-type-fa-or-h
#6
Guorui Yao, Kwok-Ho Lam, Kay Perry, Jasmin Weisemann, Andreas Rummel, Rongsheng Jin
Botulinum neurotoxins (BoNTs), which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established BoNT serotypes (BoNT/A-G), a new mosaic toxin type termed BoNT/HA (aka type FA or H) was reported recently...
March 8, 2017: Toxins
https://www.readbyqxmd.com/read/28243889/-1-h-13-c-15-n-backbone-assignment-of-the-human-heat-labile-enterotoxin-b-pentamer-and-chemical-shift-mapping-of-neolactotetraose-binding
#7
Daniel Hatlem, Julie E Heggelund, Daniel Burschowsky, Ute Krengel, Per E Kristiansen
The major virulence factor of enterotoxigenic Escherichia coli is the heat-labile enterotoxin (LT), an AB5 toxin closely related to the cholera toxin. LT consists of six subunits, the catalytically active A-subunit and five B-subunits arranged as a pentameric ring (LTB), which enable the toxin to bind to the epithelial cells in the intestinal lumen. LTB has two recognized binding sites; the primary binding site is responsible for anchoring the toxin to its main receptor, the GM1-ganglioside, while the secondary binding site recognizes blood group antigens...
February 27, 2017: Biomolecular NMR Assignments
https://www.readbyqxmd.com/read/28213222/development-of-a-qcm-d-biosensor-for-ochratoxin-a-detection-in-red-wine
#8
Aleksandra Karczmarczyk, Karsten Haupt, Karl-Heinz Feller
Ochratoxin A (OTA), a highly toxic compound, is one of the most widely spread mycotoxins that contaminates a large variety of agricultural commodities. Due to its presence in the food chain, it imposes a hazard on both human and animal health. Therefore, there is a need for precise, fast and simple methods for toxin quantification. Herein, a novel sensor based on a quartz crystal microbalance with dissipation monitoring (QCM-D) and antibodies for specific analyte recognition was developed for rapid and sensitive detection of OTA in red wine...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28199340/crystal-structure-and-structure-based-mutagenesis-of-actin-specific-adp-ribosylating-toxin-cpile-a-as-novel-enterotoxin
#9
Waraphan Toniti, Toru Yoshida, Toshiharu Tsurumura, Daisuke Irikura, Chie Monma, Yoichi Kamata, Hideaki Tsuge
Unusual outbreaks of food poisoning in Japan were reported in which Clostridium perfringens was strongly suspected to be the cause based on epidemiological information and fingerprinting of isolates. The isolated strains lack the typical C. perfringens enterotoxin (CPE) but secrete a new enterotoxin consisting of two components: C. perfringens iota-like enterotoxin-a (CPILE-a), which acts as an enzymatic ADP-ribosyltransferase, and CPILE-b, a membrane binding component. Here we present the crystal structures of apo-CPILE-a, NAD+-CPILE-a and NADH-CPILE-a...
2017: PloS One
https://www.readbyqxmd.com/read/28179499/structural-mechanistic-and-functional-insight-into-gliotoxin-bis-thiomethylation-in-aspergillus-fumigatus
#10
Stephen K Dolan, Tobias Bock, Vanessa Hering, Rebecca A Owens, Gary W Jones, Wulf Blankenfeldt, Sean Doyle
Gliotoxin is an epipolythiodioxopiperazine (ETP) class toxin, contains a disulfide bridge that mediates its toxic effects via redox cycling and is produced by the opportunistic fungal pathogen Aspergillus fumigatus Self-resistance against gliotoxin is effected by the gliotoxin oxidase GliT, and attenuation of gliotoxin biosynthesis is catalysed by gliotoxin S-methyltransferase GtmA. Here we describe the X-ray crystal structures of GtmA-apo (1.66 Å), GtmA complexed to S-adenosylhomocysteine (1.33 Å) and GtmA complexed to S-adenosylmethionine (2...
February 2017: Open Biology
https://www.readbyqxmd.com/read/28168605/synergistic-activity-between-s-layer-protein-and-spore-crystal-preparations-from-lysinibacillus-sphaericus-against-culex-quinquefasciatus-larvae
#11
Lucía C Lozano, Jenny Dussán
Lysinibacillus sphaericus is used for the biological control of mosquitoes. The main toxicity mechanism of pathogenic strains is a binary toxin produced during sporulation. S-layer is a proteinaceous structure on the surface of bacteria; its functions have been involved in the interaction between bacterial cells and the environment, for example, as protective coats, surface recognition, and biological control. In L. sphaericus, S-layer protein (SlpC) is expressed in vegetative cells, and is also found in spore-crystal preparations; it has larvicidal activity in Culex spp...
March 2017: Current Microbiology
https://www.readbyqxmd.com/read/28144706/pest-management-through-bacillus-thuringiensis-bt-in-a-tea-silkworm-ecosystem-status-and-potential-prospects
#12
REVIEW
Kavya Dashora, Somnath Roy, Akanksha Nagpal, Sudipta Mukhopadhyay Roy, Julie Flood, Anjali Km Prasad, Ravinder Khetarpal, Suzanne Neave, N Muraleedharan
Bacillus thuringiensis (Bt) is a soil bacterium that forms spores containing crystals comprising one or more Cry or Cyt proteins having potential and specific insecticidal activity. Different strains of Bt produce different types of toxins, affecting a narrow taxonomic group of insects. Therefore, it is used in non-chemical pest management, including inherent pest resistance through GM crops. The specificity of action of Bt toxins reduces the concern of adverse effects on non-target species, a concern which remains with chemical insecticides as well...
March 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28137883/tir-only-protein-rba1-recognizes-a-pathogen-effector-to-regulate-cell-death-in-arabidopsis
#13
Marc T Nishimura, Ryan G Anderson, Karen A Cherkis, Terry F Law, Qingli L Liu, Mischa Machius, Zachary L Nimchuk, Li Yang, Eui-Hwan Chung, Farid El Kasmi, Michael Hyunh, Erin Osborne Nishimura, John E Sondek, Jeffery L Dangl
Detection of pathogens by plants is mediated by intracellular nucleotide-binding site leucine-rich repeat (NLR) receptor proteins. NLR proteins are defined by their stereotypical multidomain structure: an N-terminal Toll-interleukin receptor (TIR) or coiled-coil (CC) domain, a central nucleotide-binding (NB) domain, and a C-terminal leucine-rich repeat (LRR). The plant innate immune system contains a limited NLR repertoire that functions to recognize all potential pathogens. We isolated Response to the bacterial type III effector protein HopBA1 (RBA1), a gene that encodes a TIR-only protein lacking all other canonical NLR domains...
March 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28118708/pegylation-enhances-mosquito-larvicidal-activity-of-lysinibacillus-sphaericus-binary-toxin
#14
Mahima Sharma, Ramesh S Hire, Ashok B Hadapad, Gagan D Gupta, Vinay Kumar
Toxic strains of Lysinibacillus sphaericus have been used in the field for larval control of mosquito vector diseases. The high toxicity of L. sphaericus is attributed to the binary (BinAB) toxin produced as parasporal crystalline inclusions during the early stages of sporulation. BinA and BinB, the primary components of these spore-crystals, exert high toxicity when administered together. However, instability, short half-lives, and rapid proteolytic digestion can limit their use as an effective insecticide...
February 2, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28089847/the-binding-orientation-of-epibatidine-at-%C3%AE-7-nach-receptors
#15
Andrew J Thompson, Simon Metzger, Martin Lochner, Marc-David Ruepp
Epibatidine is an alkaloid toxin that binds with high affinity to nicotinic and muscarinic acetylcholine receptors, and has been extensively used as a research tool. To examine binding interactions at the nicotinic receptor, it has been co-crystallised with the structural homologue acetylcholine binding protein (AChBP; PDB ID 2BYQ), and with an AChBP chimaera (3SQ6) that shares 64% sequence identity with the α7 nACh receptor. However, the binding orientations revealed by AChBP co-crystal structures may not precisely represent their receptor homologues and experimental evidence is needed to verify the ligand poses...
January 12, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28081148/characterization-of-multi-drug-resistant-enterococcus-faecalis-isolated-from-cephalic-recording-chambers-in-research-macaques-macaca-spp
#16
Stephanie E Woods, Mia T Lieberman, Francois Lebreton, Elise Trowel, César de la Fuente-Núñez, Joanne Dzink-Fox, Michael S Gilmore, James G Fox
Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance...
2017: PloS One
https://www.readbyqxmd.com/read/28067269/proteomic-analysis-of-cry2aa-binding-proteins-and-their-receptor-function-in-spodoptera-exigua
#17
Lin Qiu, Boyao Zhang, Lang Liu, Weihua Ma, Xiaoping Wang, Chaoliang Lei, Lizhen Chen
The bacterium Bacillus thuringiensis produces Crystal (Cry) proteins that are toxic to a diverse range of insects. Transgenic crops that produce Bt Cry proteins are grown worldwide because of their improved resistance to insect pests. Although Bt "pyramid" cotton that produces both Cry1A and Cry2A is predicted to be more resistant to several lepidopteran pests, including Spodoptera exigua, than plants that produce Cry1Ac alone, the mechanisms responsible for the toxicity of Cry2Aa in S. exigua are not well understood...
January 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28060413/molecularly-imprinted-polymer-chemosensor-for-selective-determination-of-an-n-nitroso-l-proline-food-toxin
#18
Patrycja Lach, Piyush Sindhu Sharma, Karolina Golebiewska, Maciej Cieplak, Francis D'Souza, Wlodzimierz Kutner
A molecularly imprinted polymer (MIP)-based chemosensor for the selective determination of a chosen toxin, N-nitroso-l-proline (Pro-NO), was devised and fabricated. By means of DFT, the structure of the pre-polymerization (functional monomer)-template complex was modeled. This complex was then potentiodynamically electropolymerized in the presence of cross-linking monomer to form a MIP-Pro-NO thin film. Next, the Pro-NO template was extracted from MIP-Pro-NO with 0.1 m NaOH. Piezoelectric microgravimetry (PM) on an electrochemical quartz crystal microbalance and electrochemical (differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS)) techniques were used to transduce binding of Pro-NO to molecular cavities of the MIP-Pro-NO...
November 7, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28056928/new-ligation-independent-cloning-vectors-for-expression-of-recombinant-proteins-with-a-self-cleaving-cpd-6xhis-tag
#19
Marco Biancucci, Jazel S Dolores, Jennifer Wong, Sarah Grimshaw, Wayne F Anderson, Karla J F Satchell, Keehwan Kwon
BACKGROUND: Recombinant protein purification is a crucial step for biochemistry and structural biology fields. Rapid robust purification methods utilize various peptide or protein tags fused to the target protein for affinity purification using corresponding matrices and to enhance solubility. However, affinity/solubility-tags often need to be removed in order to conduct functional and structural studies, adding complexities to purification protocols. RESULTS: In this work, the Vibrio cholerae MARTX toxin Cysteine Protease Domain (CPD) was inserted in a ligation-independent cloning (LIC) vector to create a C-terminal 6xHis-tagged inducible autoprocessing enzyme tag, called "the CPD-tag"...
January 5, 2017: BMC Biotechnology
https://www.readbyqxmd.com/read/28050633/biopolymer-microencapsulations-of-bacillus-thuringiensis-crystal-preparations-for-increased-stability-and-resistance-to-environmental-stress
#20
Xiaolin He, Zhongqin Sun, Kanglai He, Shuyuan Guo
Parasporal crystals synthesized by Bacillus thuringiensis (Bt) have been widely used as microbial pesticides because of their toxicity to the larval stages of specific insects. However, parasporal crystals can be damaged by environmental stresses, such as high temperature, ultraviolet radiation, and desiccation. To reduce environmental susceptibility of parasporal crystals and extend the duration of their activity, we developed a new type of protection by making microcapsules of crystals (MCs). The microcapsules were self-assembled by alternate deposition (layer by layer) of low-cost chitosan and sodium alginate (or sodium carboxymethyl cellulose) on the crystal surface...
January 3, 2017: Applied Microbiology and Biotechnology
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