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https://www.readbyqxmd.com/read/28705271/molecular-and-epidemiological-characterization-of-infant-botulism-in-beijing-china
#1
Yin Ping Dong, Wei Wang, Tao Jiang, Jin Xu, Chun Hui Han, Shao Fei Yan, Séamus Fanning, Ying Li, Xiao Chen Ma, Di Zhang, Yao Zhao, Biao Zeng, Feng Qin Li
Laboratory-based pathogen isolation, identification, and toxicity determination were performed on samples from a suspected case of infant botulism. Mice injected with cultures generated from the enema sample and ingested Powered infant formula (PIF) presented typical signs of botulism. Antitoxins to polyvalent botulinum neurotoxins (BoNTs) and monovalent BoNT type B antitoxin had protective effects. Clostridium botulinum isolated from the enema and residual PIF samples were positive for type B toxin. Pulsed-field gel electrophoresis (PFGE) revealed that the two strains of C...
June 2017: Biomedical and Environmental Sciences: BES
https://www.readbyqxmd.com/read/28700055/biological-and-molecular-properties-of-yellow-venom-of-the-amazonian-coral-snake-micrurus-surinamensis
#2
Fabiana da Rocha Oliveira, Maria das Dores Nogueira Noronha, Jorge Luis Lopez Lozano
INTRODUCTION: The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. METHODS: Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. RESULTS AND CONCLUSIONS: Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity...
May 2017: Revista da Sociedade Brasileira de Medicina Tropical
https://www.readbyqxmd.com/read/28696422/metagenomic-binning-of-a-marine-sponge-microbiome-reveals-unity-in-defense-but-metabolic-specialization
#3
Beate M Slaby, Thomas Hackl, Hannes Horn, Kristina Bayer, Ute Hentschel
Marine sponges are ancient metazoans that are populated by distinct and highly diverse microbial communities. In order to obtain deeper insights into the functional gene repertoire of the Mediterranean sponge Aplysina aerophoba, we combined Illumina short-read and PacBio long-read sequencing followed by un-targeted metagenomic binning. We identified a total of 37 high-quality bins representing 11 bacterial phyla and two candidate phyla. Statistical comparison of symbiont genomes with selected reference genomes revealed a significant enrichment of genes related to bacterial defense (restriction-modification systems, toxin-antitoxin systems) as well as genes involved in host colonization and extracellular matrix utilization in sponge symbionts...
July 11, 2017: ISME Journal
https://www.readbyqxmd.com/read/28691660/endoribonuclease-type-ii-toxin-antitoxin-systems-functional-or-selfish
#4
Bhaskar Chandra Mohan Ramisetty, Ramachandran Sarojini Santhosh
Most bacterial genomes have multiple type II toxin-antitoxin systems (TAs) that encode two proteins which are referred to as a toxin and an antitoxin. Toxins inhibit a cellular process, while the interaction of the antitoxin with the toxin attenuates the toxin's activity. Endoribonuclease-encoding TAs cleave RNA in a sequence-dependent fashion, resulting in translational inhibition. To account for their prevalence and retention by bacterial genomes, TAs are credited with clinically significant phenomena, such as bacterial programmed cell death, persistence, biofilms and anti-addiction to plasmids...
July 8, 2017: Microbiology
https://www.readbyqxmd.com/read/28690609/diversity-prevalence-and-longitudinal-occurrence-of-type-ii-toxin-antitoxin-systems-of-pseudomonas-aeruginosa-infecting-cystic-fibrosis-lungs
#5
Sandra B Andersen, Melanie Ghoul, Ashleigh S Griffin, Bent Petersen, Helle K Johansen, Søren Molin
Type II toxin-antitoxin (TA) systems are most commonly composed of two genes encoding a stable toxin, which harms the cell, and an unstable antitoxin that can inactivate it. TA systems were initially characterized as selfish elements, but have recently gained attention for regulating general stress responses responsible for pathogen virulence, formation of drug-tolerant persister cells and biofilms-all implicated in causing recalcitrant chronic infections. We use a bioinformatics approach to explore the distribution and evolution of type II TA loci of the opportunistic pathogen, Pseudomonas aeruginosa, across longitudinally sampled isolates from cystic fibrosis lungs...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28690594/toxin-%C3%AE-triggers-a-survival-response-to-cope-with-stress-and-persistence
#6
María Moreno-Del Álamo, Mariangela Tabone, Virginia S Lioy, Juan C Alonso
Bacteria have evolved complex regulatory controls in response to various environmental stresses. Protein toxins of the ζ superfamily, found in prominent human pathogens, are broadly distributed in nature. We show that ζ is a uridine diphosphate-N-acetylglucosamine (UNAG)-dependent ATPase whose activity is inhibited in vitro by stoichiometric concentrations of ε2 antitoxin. In vivo, transient ζ expression promotes a reversible multi-level response by altering the pool of signaling purine nucleotides, which leads to growth arrest (dormancy), although a small cell subpopulation persists rather than tolerating toxin action...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28687759/emerging-patterns-of-plasmid-host-coevolution-that-stabilize-antibiotic-resistance
#7
Thibault Stalder, Linda M Rogers, Chris Renfrow, Hirokazu Yano, Zachary Smith, Eva M Top
Multidrug resistant bacterial pathogens have become a serious global human health threat, and conjugative plasmids are important drivers of the rapid spread of resistance to last-resort antibiotics. Whereas antibiotics have been shown to select for adaptation of resistance plasmids to their new bacterial hosts, or vice versa, a general evolutionary mechanism has not yet emerged. Here we conducted an experimental evolution study aimed at determining general patterns of plasmid-bacteria evolution. Specifically, we found that a large conjugative resistance plasmid follows the same evolutionary trajectories as its non-conjugative mini-replicon in the same and other species...
July 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28677629/mechanisms-for-differential-protein-production-in-toxin-antitoxin-systems
#8
Heather S Deter, Roderick V Jensen, William H Mather, Nicholas C Butzin
Toxin-antitoxin (TA) systems are key regulators of bacterial persistence, a multidrug-tolerant state found in bacterial species that is a major contributing factor to the growing human health crisis of antibiotic resistance. Type II TA systems consist of two proteins, a toxin and an antitoxin; the toxin is neutralized when they form a complex. The ratio of antitoxin to toxin is significantly greater than 1.0 in the susceptible population (non-persister state), but this ratio is expected to become smaller during persistence...
July 4, 2017: Toxins
https://www.readbyqxmd.com/read/28676719/srna-and-cis-antisense-srna-identification-in-staphylococcus-aureus-highlights-an-unusual-srna-gene-cluster-with-one-encoding-a-secreted-peptide
#9
Julie Bronsard, Gaetan Pascreau, Mohamed Sassi, Tony Mauro, Yoann Augagneur, Brice Felden
The human pathogen Staphylococcus aureus expresses a set of transcriptional factors and small RNAs (sRNAs) to adapt to environmental variations. Recent harmonization of staphylococcal sRNA data allowed us to search for novel sRNAs using DETR'PROK, a computational pipeline for identifying sRNA in prokaryotes. We performed RNA-Seq on Newman strain and identified a set of 48 sRNA candidates. To avoid bioinformatic artefacts, we applied a series of cut-offs and tested experimentally each selected intergenic region...
July 4, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28675659/characterization-of-a-deinococcus-radiodurans-mazf-a-uaca-specific-rna-endoribonuclease
#10
Tatsuki Miyamoto, Yuri Ota, Akiko Yokota, Tetsushi Suyama, Satoshi Tsuneda, Naohiro Noda
Microbes are known to withstand environmental stresses by using chromosomal toxin-antitoxin systems. MazEF is one of the most extensively studied toxin-antitoxin systems. In stressful environments, MazF toxins modulate translation by cleaving single-stranded RNAs in a sequence-specific fashion. Previously, a chromosomal gene located at DR0417 in Deinococcus radiodurans was predicted to code for a MazF endoribonuclease (MazFDR0417 ); however, its function remains unclear. In the present study, we characterized the molecular function of MazFDR0417 ...
July 3, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28674066/contribution-of-the-chromosomal-ccdab-operon-to-bacterial-drug-tolerance
#11
Kritika Gupta, Arti Tripathi, Alishan Sahu, Raghavan Varadarajan
One of the first identified and best studied toxin-antitoxin systems in Escherichia coli is the F-plasmid based CcdAB system. This system is involved in plasmid maintenance through post-segregational killing. More recently, ccdAB homologs have been found on the chromosome, including in pathogenic strains of E. coli and other bacteria. However the functional role of chromosomal ccdAB genes, if any, has remained unclear. We show that both the native ccd operon of the E.coliO157 strain, as well as the ccd operon from the F- plasmid, when inserted on the E...
July 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28669616/clostridium-difficile-chimeric-toxin-receptor-binding-domain-vaccine-induced-protection-against-different-strains-in-active-and-passive-challenge-models
#12
Jing-Hui Tian, Gregory Glenn, David Flyer, Bin Zhou, Ye Liu, Eddie Sullivan, Hua Wu, James F Cummings, Larry Elllingsworth, Gale Smith
Clostridium difficile is the number one cause of nosocomial antibiotic-associated diarrhea in developed countries. Historically, pathogenesis was attributed two homologous glucosylating toxins, toxin-A (TcdA) and toxin-B (TcdB). Over the past decade, however, highly virulent epidemic strains of C. difficile (B1/NAP1/027) have emerged and are linked to an increase in morbidity and mortality. Increased virulence is attributed to multiple factors including: increased production of A- and B-toxins; production of binary toxin (CDT); and the emergence of more toxic TcdB variants (TcdB(027))...
July 24, 2017: Vaccine
https://www.readbyqxmd.com/read/28652353/disentangling-the-effects-of-selection-and-loss-bias-on-gene-dynamics
#13
Jaime Iranzo, José A Cuesta, Susanna Manrubia, Mikhail I Katsnelson, Eugene V Koonin
We combine mathematical modeling of genome evolution with comparative analysis of prokaryotic genomes to estimate the relative contributions of selection and intrinsic loss bias to the evolution of different functional classes of genes and mobile genetic elements (MGE). An exact solution for the dynamics of gene family size was obtained under a linear duplication-transfer-loss model with selection. With the exception of genes involved in information processing, particularly translation, which are maintained by strong selection, the average selection coefficient for most nonparasitic genes is low albeit positive, compatible with observed positive correlation between genome size and effective population size...
June 26, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28637172/identification-of-four-type-ii-toxin-antitoxin-systems-in-actinobacillus-pleuropneumoniae
#14
Chengkun Zheng, Xigong Zhao, Ting Zeng, Manman Cao, Jiali Xu, Guolin Shi, Jinquan Li, Huanchun Chen, Weicheng Bei
Toxin-antitoxin systems are small genetic elements that are widely prevalent in the genomes of bacteria and archaea. These modules have been identified in various bacteria and proposed to play an important role in bacterial physiology and virulence. However, their presence in the genomes of Actinobacillus species has received no attention. In this study, we describe the identification of four type II TA systems in Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia. Reverse transcription PCR analysis revealed that the genes encoding the toxin and antitoxin are co-transcribed...
June 20, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28621109/comparative-genomic-analysis-of-lactobacillus-plantarum-gb-lp1-isolated-from-traditional-korean-fermented-food
#15
Jihyun Yu, Sojin Ahn, Kwondo Kim, Kelsey Caetano-Anolles, Chanho Lee, Jungsun Kang, Kyungjin Cho, SookHee Yoon, Dae-Kyung Kang, Heebal Kim
As probiotics play an important role in maintaining a healthy gut flora environment through antitoxin activity and inhibition of pathogen colonization, they have been of interest to the medical research community for quite some time now. Probiotic bacteria such as Lactobacillus plantarum, which can be found in fermented food, are of particular interest given their easy accessibility. We performed whole genome sequencing and genomic analysis on a GB-LP1 strain of L. plantarum isolated from Korean traditional fermented food; this strain is well known for its functions in immune response, suppression of pathogen growth and anti-toxin effects...
June 16, 2017: Journal of Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28620370/environmental-t4-family-bacteriophages-evolve-to-escape-abortive-infection-via-multiple-routes-in-a-bacterial-host-employing-altruistic-suicide-through-type-iii-toxin-antitoxin-systems
#16
Bihe Chen, Chidiebere Akusobi, Xinzhe Fang, George P C Salmond
Abortive infection is an anti-phage mechanism employed by a bacterium to initiate its own death upon phage infection. This reduces, or eliminates, production of viral progeny and protects clonal siblings in the bacterial population by an act akin to an "altruistic suicide." Abortive infection can be mediated by a Type III toxin-antitoxin system called ToxINPa consisting of an endoribonuclease toxin and RNA antitoxin. ToxINPa is a heterohexameric quaternary complex in which pseudoknotted RNA inhibits the toxicity of the toxin until infection by certain phages causes destabilization of ToxINPa, leading to bacteriostasis and, eventually, lethality...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28612721/-addiction-of-toxin-antitoxin-systems-to-a-chaperone-in-mycobacterium-tuberculosis
#17
Patricia Bordes, Pierre Genevaux
No abstract text is available yet for this article.
May 2017: Médecine Sciences: M/S
https://www.readbyqxmd.com/read/28575517/comprehensive-classification-of-the-pin-domain-like-superfamily
#18
Dorota Matelska, Kamil Steczkiewicz, Krzysztof Ginalski
PIN-like domains constitute a widespread superfamily of nucleases, diverse in terms of the reaction mechanism, substrate specificity, biological function and taxonomic distribution. Proteins with PIN-like domains are involved in central cellular processes, such as DNA replication and repair, mRNA degradation, transcription regulation and ncRNA maturation. In this work, we identify and classify the most complete set of PIN-like domains to provide the first comprehensive analysis of sequence-structure-function relationships within the whole PIN domain-like superfamily...
May 31, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28575388/functional-details-of-the-mycobacterium-tuberculosis-vapbc26-toxin-antitoxin-system-based-on-a-structural-study-insights-into-unique-binding-and-antibiotic-peptides
#19
Sung-Min Kang, Do-Hee Kim, Ki-Young Lee, Sung Jean Park, Hye-Jin Yoon, Sang Jae Lee, Hookang Im, Bong-Jin Lee
Toxin-antitoxin (TA) systems are essential for bacterial persistence under stressful conditions. In particular, Mycobacterium tuberculosis express VapBC TA genes that encode the stable VapC toxin and the labile VapB antitoxin. Under normal conditions, these proteins interact to form a non-toxic TA complex, but the toxin is activated by release from the antitoxin in response to unfavorable conditions. Here, we present the crystal structure of the M. tuberculosis VapBC26 complex and show that the VapC26 toxin contains a pilus retraction protein (PilT) N-terminal (PIN) domain that is essential for ribonuclease activity and that, the VapB26 antitoxin folds into a ribbon-helix-helix DNA-binding motif at the N-terminus...
May 31, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28574452/two-synechococcus-genes-two-different-effects-on-cyanophage-infection
#20
Ayalla Fedida, Debbie Lindell
Synechococcus is an abundant marine cyanobacterium that significantly contributes to primary production. Lytic phages are thought to have a major impact on cyanobacterial population dynamics and evolution. Previously, an investigation of the transcriptional response of three Synechococcus strains to infection by the T4-like cyanomyovirus, Syn9, revealed that while the transcript levels of the vast majority of host genes declined soon after infection, those for some genes increased or remained stable. In order to assess the role of two such host-response genes during infection, we inactivated them in Synechococcus sp...
June 2, 2017: Viruses
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