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https://www.readbyqxmd.com/read/28820009/expression-of-a-vibrio-parahaemolyticus-toxin-in-escherichia-coli-results-in-chromosomal-dna-degradation
#1
Jing Zhang, Saki Taniguchi, Hironori Ito, Kazuhiro Iiyama, Madoka Hino, Tsutomu Katayama, Makoto Kimura
A toxin-antitoxin system, vp1842/vp1843, locates within a superintegron on the Vibrio parahaemolyticus genome chromosome I whose toxin gene vp1843 encodes a DNA nicking endonuclease. We found that the vp1843 expression in Escherichia coli cells strongly induced chromosomal DNA degradation. On the basis of these observations, we discuss a possible physiological role of vp1842/vp1843 in V. parahaemolyticus.
August 18, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28802584/molecular-characterization-of-the-pa3j1-plasmid-from-the-psychrotolerant-antarctic-bacterium-pseudomonas-sp-ant_j3
#2
Krzysztof Romaniuk, Tomasz Krucon, Przemyslaw Decewicz, Adrian Gorecki, Lukasz Dziewit
The knowledge on plasmids of cold-active bacteria is highly limited. In this study, the molecular characterization of the pA3J1 plasmid of Antarctic psychrotolerant bacterium Pseudomonas sp. ANT_J3 was performed. Within this plasmid, thirteen putative open reading frames were identified. Nine of them encoded proteins involved in replication, partitioning, postsegregational elimination of plasmid-less cells (via a toxin-antitoxin system activity), multimer resolution and mobilization by conjugal transfer. These genes constitute the plasmid backbone...
August 9, 2017: Plasmid
https://www.readbyqxmd.com/read/28798741/deinococcus-radiodurans-toxin-antitoxin-mazef-dr-mediates-cell-death-in-response-to-dna-damage-stress
#3
Tao Li, Yulan Weng, Xiaoqiong Ma, Bing Tian, Shang Dai, Ye Jin, Mengjia Liu, Jiulong Li, Jiangliu Yu, Yuejin Hua
Here we identified a functional MazEF-dr system in the exceptionally stress-resistant bacterium D. radiodurans. We showed that overexpression of the toxin MazF-dr inhibited the growth of Escherichia coli. The toxic effect of MazF-dr was due to its sequence-specific endoribonuclease activity on RNAs containing a consensus 5'ACA3', and it could be neutralized by MazE-dr. The MazF-dr showed a special cleavage preference for the nucleotide present before the ACA sequence with the order by U>A>G>C. MazEF-dr mediated the death of D...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28777088/production-biophysical-characterization-and-crystallization-of-pseudomonas-putida-graa-and-its-complexes-with-grat-and-the-grata-operator
#4
Ariel Talavera, Hedvig Tamman, Andres Ainelo, San Hadǽi, Abel Garcia-Pino, Rita Hõrak, Albert Konijnenberg, Remy Loris
The graTA operon from Pseudomonas putida encodes a toxin-antitoxin module with an unusually moderate toxin. Here, the production, SAXS analysis and crystallization of the antitoxin GraA, the GraTA complex and the complex of GraA with a 33 bp operator fragment are reported. GraA forms a homodimer in solution and crystallizes in space group P21, with unit-cell parameters a = 66.9, b = 48.9, c = 62.7 Å, β = 92.6°. The crystals are likely to contain two GraA dimers in the asymmetric unit and diffract to 1...
August 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
https://www.readbyqxmd.com/read/28770009/complete-genome-sequence-of-a-commensal-bacterium-hafnia-alvei-cba7124-isolated-from-human-feces
#5
Hye Seon Song, Joon Yong Kim, Yeon Bee Kim, Myeong Seon Jeong, Jisu Kang, Jin-Kyu Rhee, Joseph Kwon, Ju Suk Kim, Jong-Soon Choi, Hak-Jong Choi, Young-Do Nam, Seong Woon Roh
BACKGROUND: Members of the genus Hafnia have been isolated from the feces of mammals, birds, reptiles, and fish, as well as from soil, water, sewage, and foods. Hafnia alvei is an opportunistic pathogen that has been implicated in intestinal and extraintestinal infections in humans. However, its pathogenicity is still unclear. In this study, we isolated H. alvei from human feces and performed sequencing as well as comparative genomic analysis to better understand its pathogenicity. RESULTS: The genome of H...
2017: Gut Pathogens
https://www.readbyqxmd.com/read/28737000/chemoprofile-and-functional-diversity-of-fungal-and-bacterial-endophytes-and-role-of-ecofactors-a-review
#6
REVIEW
Aiyatullah Shah, Qazi Parvaiz Hassan, Saleem Mushtaq, Aabid Manzoor Shah, Aehtesham Hussain
Endophytes represent a hidden world within plants. Almost all plants that are studied harbor one or more endophytes, which help their host to survive against pathogens and changing adverse environmental conditions. Fungal and bacterial endophytes with distinct ecological niches show important biological activities and ecological functions. Their unique physiological and biochemical characteristics lead to the production of niche specific secondary metabolites that may have pharmacological potential. Identification of specific secondary metabolites in adverse environment can also help us in understanding mechanisms of host tolerance against stress condition such as biological invasions, salt, drought, temperature...
July 24, 2017: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/28732463/common-and-phylogenetically-widespread-coding-for-peptides-by-bacterial-small-rnas
#7
Robin C Friedman, Stefan Kalkhof, Olivia Doppelt-Azeroual, Stephan A Mueller, Martina Chovancová, Martin von Bergen, Benno Schwikowski
BACKGROUND: While eukaryotic noncoding RNAs have recently received intense scrutiny, it is becoming clear that bacterial transcription is at least as pervasive. Bacterial small RNAs and antisense RNAs (sRNAs) are often assumed to be noncoding, due to their lack of long open reading frames (ORFs). However, there are numerous examples of sRNAs encoding for small proteins, whether or not they also have a regulatory role at the RNA level. METHODS: Here, we apply flexible machine learning techniques based on sequence features and comparative genomics to quantify the prevalence of sRNA ORFs under natural selection to maintain protein-coding function in 14 phylogenetically diverse bacteria...
July 21, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28729858/toxin-antitoxin-systems-in-estuarine-synechococcus-strain-cb0101-and-their-transcriptomic-responses-to-environmental-stressors
#8
David Marsan, Allen Place, Daniel Fucich, Feng Chen
Bacterial toxin-antitoxin (TA) systems are genetic elements composed of a toxin gene and its cognate antitoxin, with the ability to regulate growth. TA systems have not previously been reported in marine Synechococcus or Prochlorococcus. Here we report the finding of seven TA system pairs (Type II) in the estuarine Synechococcus CB0101, and their responses of these TA genes to under different stress conditions, which include; nitrogen and phosphate starvation, phage infection, zinc toxicity, and photo-oxidation...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28726719/sima-cells-for-a-serotype-specific-and-sensitive-cell-based-neutralization-test-for-botulinum-toxin-a-and-e
#9
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/28724903/co-expression-network-analysis-of-toxin-antitoxin-loci-in-mycobacterium-tuberculosis-reveals-key-modulators-of-cellular-stress
#10
Amita Gupta, Balaji Venkataraman, Madavan Vasudevan, Kiran Gopinath Bankar
Research on toxin-antitoxin loci (TA loci) is gaining impetus due to their ubiquitous presence in bacterial genomes and their observed roles in stress survival, persistence and drug tolerance. The present study investigates the expression profile of all the seventy-nine TA loci found in Mycobacterium tuberculosis. The bacterium was subjected to multiple stress conditions to identify key players of cellular stress response and elucidate a TA-coexpression network. This study provides direct experimental evidence for transcriptional activation of each of the seventy-nine TA loci following mycobacterial exposure to growth-limiting environments clearly establishing TA loci as stress-responsive modules in M...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28705271/molecular-and-epidemiological-characterization-of-infant-botulism-in-beijing-china
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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