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Microbiology

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https://www.readbyqxmd.com/read/27926818/disruption-of-miaa-provides-insights-into-the-regulation-of-phenazine-biosynthesis-under-suboptimal-growth-conditions-in-pseudomonas-chlororaphis-30-84
#1
Jun Myoung Yu, Donping Wang, Leland S Pierson, Elizabeth A Pierson
Many products of secondary metabolism are activated by quorum sensing (QS), yet even at cell densities sufficient for QS, their production may be repressed under suboptimal growth conditions via mechanisms that still require elucidation. For many beneficial plant-associated bacteria, secondary metabolites such as phenazines are important for their competitive survival and plant-protective activities. Previous work established that phenazine biosynthesis in Pseudomonas chlororaphis 30-84 is regulated by the PhzR/PhzI QS system, which in turn is regulated by transcriptional regulator Pip, two-component system RpeA/RpeB, and stationary-phase/stress sigma factor RpoS...
December 7, 2016: Microbiology
https://www.readbyqxmd.com/read/27926815/identification-of-lysophospholipase-protein-from-spiroplasma-eriocheiris-and-verification-of-its-function
#2
Huanxi Zhu, Peng Liu, Jie Du, Jian Wang, Yunting Jing, Jia Zhang, Wei Gu, Wen Wang, Qingguo Meng
Spiroplasma eriocheiris is known to cause the tremor disease in the Chinese mitten crab Eriocheir sinensis; however, the molecular characterization of this pathogen is still unclear. S. eriocheiris has the ability to invade and survive within mouse 3T6 cells. The invasion process may require causing damage to the host cell membrane by chemical, physical, or enzymatic means. In this study, we systematically characterized a novel lysophospholipase (lysoPL) of S. eriocheiris TDA-040725-5T. The gene that encodes lysoPL in S...
December 7, 2016: Microbiology
https://www.readbyqxmd.com/read/27926824/identification-and-characterization-of-chemosensors-for-d-malate-unnatural-enantiomer-of-malate-in-ralstonia-pseudosolanacearum
#3
Mattana Tunchai, Akiko Hida, Shota Oku, Yutaka Nakashimada, Takahisa Tajima, Junichi Kato
Ralstonia pseudosolanacearum Ps29 is attracted by nonmetabolizable D-malate, an unnatural enantiomer. Screening of a complete collection of single-mcp-gene deletion mutants of Ps29 revealed that the RSc1156 homolog is a chemosensor for D-malate. An RSc1156 homolog deletion mutant of Ps29 showed decreased but significant responses to D-malate, suggesting the existence of another D-malate chemosensor. McpM previously had been identified as a chemosensor for L-malate. We constructed an RSc1156 homolog mcpM double deletion mutant and noted that this mutant failed to respond to D-malate; thus, the RSc1156 homolog and McpM are the major chemosensors for D-malate in this organism...
December 2, 2016: Microbiology
https://www.readbyqxmd.com/read/27902439/evidence-that-pneumococcal-walk-is-regulated-by-stkp-through-protein-protein-interaction
#4
Gro Anita Stamsås, Daniel Straume, Zhian Salehian, Leiv Sigve Håvarstein
WalRK is the only two-component regulatory system essential for viability in Streptococcus pneumoniae. Despite its importance, the biological role of this system is not well understood. However, previous studies have shown that it has a crucial role in controlling pneumococcal cell division. Considerable efforts have been made to understand how the WalRK system is regulated, but no signal(s) sensed by the WalK histidine kinase has been identified so far. Here, we provide evidence that the serine/threonine protein kinase StkP modulates the activity of WalK through direct protein-protein interaction, suggesting that this interaction is one of the signals sensed by WalK...
November 29, 2016: Microbiology
https://www.readbyqxmd.com/read/27902413/methanosarcina-acetivorans-utilizes-a-single-nadph-dependent-thioredoxin-system-and-contains-additional-thioredoxin-homologs-with-distinct-functions
#5
Addison C McCarver, Faith H Lessner, Jose M Soroeta, Daniel J Lessner
The thioredoxin system plays a central role in the intracellular redox maintenance in the majority of cells. The canonical system is comprised of an NADPH-dependent thioredoxin reductase (TrxR) that reduces the disulfide reductase thioredoxin (Trx). Although Trx is encoded in almost all sequenced genomes of methanogens, its incorporation into their unique physiology is not well understood. Methanosarcina acetivorans contains a single TrxR (MaTrxR) and seven Trx (MaTrx1-7) homologs. We previously showed that MaTrxR and at least MaTrx7 comprise a functional NADPH-dependent thioredoxin system...
November 29, 2016: Microbiology
https://www.readbyqxmd.com/read/27902435/overexpression-of-the-fratricide-immunity-protein-comm-leads-to-growth-inhibition-and-morphological-abnormalities-in-streptococcus-pneumoniae
#6
Daniel Straume, Gro Anita Stamsås, Zhian Salehian, Leiv Sigve Håvarstein
The important human pathogen Streptococcus pneumoniae is a naturally transformable species. When developing the competent state, it expresses proteins involved in DNA-uptake, DNA-processing and homologous recombination. In addition to the proteins required for the transformation process, competent pneumococci express proteins involved in a predatory DNA-acquisition-mechanism termed fratricide. This is a mechanism by which the competent pneumococci secrete a muralytic fratricin termed CbpD, which lyse susceptible sister cells or closely related streptococcal species...
November 28, 2016: Microbiology
https://www.readbyqxmd.com/read/27902428/high-concentrations-of-intracellular-ap4a-and-or-ap5a-in-developing-myxococcus-xanthus-cells-inhibit-sporulation
#7
Yoshio Kimura, Chihiro Tanaka, Katsuho Sasaki, Masashi Sasaki
Diadenosine polyphosphates (ApnA) are thought to act as signaling molecules regulating stress responses and biofilm formation in prokaryotes. However, ApnA function in Myxococcus xanthus remains unknown. Here, we investigated the role of ApnA in M. xanthus, using the wild-type and ApnA hydrolase (apaH) mutant strains exposed to various stress conditions. In both wild-type and apaH mutant cells cultured on starvation medium (CF agar), the levels of intracellular diadenosine tetraphosphate (Ap4A) and pentaphosphate (Ap5A) increased several fold during the first 16 h of development, and decreased gradually thereafter...
November 28, 2016: Microbiology
https://www.readbyqxmd.com/read/27902442/the-whcd-gene-of-corynebacterium-glutamicum-plays-roles-in-cell-division-and-envelope-formation
#8
Dong-Seok Lee, Younhee Kim, Heung-Shick Lee
In this study, we analyzed the whcD gene from Corynebacterium glutamicum, which encodes a homolog of whiB, a Streptomyces coelicolor gene required for the sporulation of aerial hyphae. Deletion of the gene (ΔwhcD) severely affected cell growth in C. glutamicum. The ΔwhcD strain exhibited a large, filamentous, branched, and bud-shaped morphology with multiple septa. The transcription levels of the cell division genes involved in Z-ring assembly and septal peptidoglycan synthesis, including ftsZ, sepF, ftsQ, and ftsI, were markedly decreased in the ΔwhcD strain...
November 24, 2016: Microbiology
https://www.readbyqxmd.com/read/27902438/dna-double-strand-break-repair-is-involved-in-desiccation-resistance-of-sinorhizobium-meliloti-but-is-not-essential-for-its-symbiotic-interaction-with-medicago-truncatula
#9
Pierre Dupuy, Benjamin Gourion, Laurent Sauviac, Claude Bruand
The soil bacterium Sinorhizobium meliloti, a nitrogen-fixing symbiont of legume plants, is exposed to numerous stress conditions in nature, some of which cause the formation of harmful DNA double strand breaks (DSB). In particular, the reactive oxygen (ROS) and nitrogen (RNS) species produced during symbiosis, and the desiccation occurring in dry soils, are conditions which induce DSB. Two major systems of DSB repair are known in S. meliloti: homologous recombination (HR) and non-homologous end-joining (NHEJ)...
November 23, 2016: Microbiology
https://www.readbyqxmd.com/read/27902434/interaction-and-signalling-networks-a-report-from-the-fourth-young-microbiologists-symposium-on-microbe-signalling-organisation-and-pathogenesis
#10
Clare L Kirkpatrick, Oliver Lesouhaitier, Jacob G Malone, Shi-Qi An, Delphine L Caly
No abstract text is available yet for this article.
November 23, 2016: Microbiology
https://www.readbyqxmd.com/read/27902423/characterization-of-cis-elements-in-the-promoter-of-trz2-encoding-schizosaccharomyces-pombe-mitochondrial-trna-3-end-processing-enzyme
#11
Jinyu Liu, Linting Huang, Yirong Wang, Ying Huang
The endonuclease tRNase Z is responsible for the 3'-end processing of tRNA precursors, which is one of the essential steps in tRNA maturation. The fission yeast Schizosaccharomyces pombe contains two essential tRNase ZL genes (trz1 and trz2) involved in nuclear and mitochondrial tRNA 3'-end processing, respectively. Our previous studies suggest that trz2 is expressed at a very low level. Here we report characterization of the trz2 promoter. Using lacZ as a reporter, we show that the trz2 promoter contains a HomolD box and a very weak diverged TATA element...
November 22, 2016: Microbiology
https://www.readbyqxmd.com/read/27902417/lantibiotics-produced-by-actinobacteria-and-their-potential-applications-a-review
#12
Karen Gomes, Rafael Silva Duarte, Maria do Carmo de Freire Bastos
The phylum Actinobacteria, which comprises a great variety of Gram-positive bacteria with a high G+C content in their genomes, is known for its large production of bioactive compounds, including those with antimicrobial activity. Among the antimicrobials, bacteriocins, ribosomally-synthesized peptides, represent an important arsenal of potential new drugs to face the increasing prevalence of resistance to antibiotics among microbial pathogens. The actinobacterial bacteriocins form a heterogeneous group of substances that is difficult to adapt to most proposed classification schemes...
November 22, 2016: Microbiology
https://www.readbyqxmd.com/read/27902426/unravelling-the-biosynthesis-of-pyriculol-in-the-rice-blast-fungus-magnaporthe-oryzae
#13
Stefan Jacob, Thomas Grötsch, Andrew J Foster, Anja Schüffler, Patrick H Rieger, Louis P Sandjo, Johannes C Liermann, Till Opatz, Eckhard Thines
Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus Magnaporthe oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives...
November 17, 2016: Microbiology
https://www.readbyqxmd.com/read/27902436/exploring-the-parameters-of-post-segregation-killing-using-heterologous-expression-of-secreted-toxin-barnase-and-antitoxin-barstar-in-an-e-coli-case-study
#14
Dorien S Coray, Brigitta Kurenbach, Jack A Heinemann
Post-segregational killing (PSK) is a phenotype determined by plasmids using a toxin and an antitoxin (TA) gene pair. Loss of the genes depletes the cell's reserve of antitoxin and allows the toxin to act upon the cell. PSK benefits mobile elements when it increases reproductive success relative to other mobile competitors. A side effect of PSK is that plasmids become refractory to displacement from the cell during growth as a monoculture. Most PSK systems use a cytoplasmic toxin, but the external toxins of bacteriocins also have a PSK-like effect...
November 16, 2016: Microbiology
https://www.readbyqxmd.com/read/27902415/inversion-of-correia-repeat-enclosed-elements-in-neisseria-gonorrhoeae
#15
Firat Elbeyioglu, Sabrina B Roberts, Russell Spencer-Smith, Madhuri Pulijala, Marta A Zelewska, Jean-Christophe Nebel, Lori As Snyder
Neisseria gonorrhoeae is capable of causing gonorrhoea and more complex diseases in the human host. Within the gonococcal genome are over 100 copies of the IS-like Correia Repeat Enclosed Element, which has been predicted to be mobile within the neisserial genomes. Although there is evidence of ancestral movement of these elements, no previous study has provided evidence for current mobilisation. The Correia Repeat Enclosed Element has the ability to alter gene expression and regulation in many ways: by insertional mutagenesis; by introducing promoter elements; by generating mRNA processing sites, and by association with ncRNAs...
November 16, 2016: Microbiology
https://www.readbyqxmd.com/read/27902425/virulence-adaptations-of-pseudomonas-aeruginosa-isolated-from-patients-with-non-cystic-fibrosis-bronchiectasis
#16
Taylor Evart Woo, Jessica Duong, Nicole M Jervis, Harvey R Rabin, Michael D Parkins, Douglas Gordon Storey
Pseudomonas aeruginosa is a major pathogen in chronic lung diseases such as cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis (nCFB). Much of our understanding regarding infections in nCFB patients is extrapolated from findings in CF with little direct investigation on the adaptation of P. aeruginosa in nCFB patients. As such, we investigated whether the adaptation of P. aeruginosa was indeed similar between nCFB and CF. From our prospectively collected biobank we identified 40 nCFB patients who had repeated P...
November 8, 2016: Microbiology
https://www.readbyqxmd.com/read/27902427/phenotypic-and-genetic-characterization-of-multi-drug-resistant-staphylococcus-aureus-in-the-tropics-of-southeast-asia
#17
Siti Norayuni Mohd Zulkeflle, Yus Amira Yusaimi, Norio Sugiura, Koji Iwamoto, Masafumi Goto, Motoo Utsumi, Nor'azizi Bin Othman, Zuriati Zakaria, Hirofumi Hara
Antibiotic resistance has become a major public health problem throughout the world. The presence of antibiotic resistant bacteria such as Staphylococcus aureus (S. aureus) and antibiotic resistance genes (ARGs) in hospital wastewater is cause for great concern today. In this study, 276 S. aureus isolates were recovered from hospital wastewater samples in Malaysia. All of the isolates were screened for susceptibility to nine different classes of antibiotics: ampicillin (AMP), ciprofloxacin (CFX), gentamicin (GMN), kanamycin (KMN), erythromycin (ERM), vancomycin (VAN), trimetoprim and sulfamethaxazole (TM-SMZ), chloramphenicol (CMP), tetracycline (TET), and nalidixic acid (NAL)...
November 3, 2016: Microbiology
https://www.readbyqxmd.com/read/27902416/the-xylella-fastidiosa-codiro-strain-associated-with-the-olive-quick-decline-syndrome-in-southern-italy-belongs-to-a-clonal-complex-of-the-subspecies-pauca-that-evolved-in-central-america
#18
Marco Scortichini, Simone Marcelletti
Xylella fastidiosa, a xylem-limited bacterium transmitted by xylem-fluid feeding Hemiptera insects, causes economic losses of both woody and herbaceous plant species. A X. fastidiosa subsp. pauca strain, namely CoDiRO, was recently found to be associated with the "olive quick decline syndrome" in southern Italy (i.e., Apulia region). Recently, some X. fastidiosa strains intercepted in France from Coffea spp. plant cuttings imported from Central and South America were characterized. The introduction of infected plant material from Central America in Apulia was also postulated even though an ad hoc study to confirm this hypothesis is lacking...
November 2, 2016: Microbiology
https://www.readbyqxmd.com/read/27902440/synechococcus-diversity-along-a-trophic-gradient-in-the-osterseen-lake-district-bavaria
#19
Joachim Ruber, Franziska Bauer, Andrew Millard, Uta Raeder, Jürgen Geist, Katrin Zwirglmaier
Picocyanobacteria are important primary producers in freshwater, however there is still a knowledge gap regarding their diversity at the strain level. For this reason, the microbial diversity of four lakes with different trophic states was investigated by sequencing of the 16S rRNA gene using universal primers. The study was performed in selected lakes of the Osterseen Lake District, Germany, from 2012 to 2014 (Lake Schiffhuettensee: eutrophic; Lake Ostersee: meso-oligotrophic; Lake Groebensee: oligotrophic; Lake Lustsee: oligotrophic)...
November 1, 2016: Microbiology
https://www.readbyqxmd.com/read/27902421/domain-evolution-in-enzymes-of-the-neopullulanase-subfamily
#20
Andrea Kuchtova, Stefan Janecek
Among the glycoside hydrolases (GHs) classified within the CAZy database, the α-amylase family GH13 containing ~30 different enzyme specificities and more than 37,000 sequences, represents one of the largest GH families. Earlier, based on a characteristic sequence motif in their 5th conserved sequence region (CSR), the two closely related subfamilies, the so-called oligo-1,6-glucosidase and neopullulanase subfamilies were described. Currently the two subfamilies cover several CAZy-defined GH13 subfamilies because the α-amylase family GH13 has officially been divided into 41 subfamilies...
November 1, 2016: Microbiology
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