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https://www.readbyqxmd.com/read/28436122/metabolic-engineering-of-escherichia-coli-for-production-of-2-phenylethylacetate-from-l-phenylalanine
#1
Daoyi Guo, Lihua Zhang, Hong Pan, Xun Li
In order to meet the need of consumer preferences for natural flavor compounds, microbial synthesis method has become a very attractive alternative to the chemical production. The 2-phenylethanol (2-PE) and its ester 2-phenylethylacetate (2-PEAc) are two extremely important flavor compounds with a rose-like odor. In recent years, Escherichia coli and yeast have been metabolically engineered to produce 2-PE. However, a metabolic engineering approach for 2-PEAc production is rare. Here, we designed and expressed a 2-PEAc biosynthetic pathway in E...
April 24, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28425179/resilience-of-the-prokaryotic-microbial-community-of-acropora-digitifera-to-elevated-temperature
#2
Andrian P Gajigan, Leomir A Diaz, Cecilia Conaco
The coral is a holobiont formed by the close interaction between the coral animal and a diverse community of microorganisms, including dinoflagellates, bacteria, archaea, fungi, and viruses. The prokaryotic symbionts of corals are important for host fitness but are also highly sensitive to changes in the environment. In this study, we used 16S ribosomal RNA (rRNA) sequencing to examine the response of the microbial community associated with the coral, Acropora digitifera, to elevated temperature. The A. digitifera microbial community is dominated by operational taxonomic unit (OTUs) affiliated with classes Alphaproteobacteria and Gammaproteobacteria...
April 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28419759/regulation-of-burkholderia%C3%A2-cenocepacia-biofilm-formation-by-rpon-and-the-c-di-gmp-effector-berb
#3
Mustafa Fazli, Morten Rybtke, Elisabeth Steiner, Elisabeth Weidel, Jens Berthelsen, Julie Groizeleau, Wu Bin, Boo Zhao Zhi, Zhang Yaming, Volkhard Kaever, Michael Givskov, Rolf W Hartmann, Leo Eberl, Tim Tolker-Nielsen
Knowledge about the molecular mechanisms that are involved in the regulation of biofilm formation is essential for the development of biofilm-control measures. It is well established that the nucleotide second messenger cyclic diguanosine monophosphate (c-di-GMP) is a positive regulator of biofilm formation in many bacteria, but more knowledge about c-di-GMP effectors is needed. We provide evidence that c-di-GMP, the alternative sigma factor RpoN (σ54), and the enhancer-binding protein BerB play a role in biofilm formation of Burkholderia cenocepacia by regulating the production of a biofilm-stabilizing exopolysaccharide...
April 16, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28419748/the-known-genetic-potential-for-microbial-communities-to-degrade-organic-phosphorus-is-reduced-in-low-ph-soils
#4
Ian D E A Lidbury, Tandra Fraser, Andrew R J Murphy, David J Scanlan, Gary D Bending, Alexandra M E Jones, Jonathan D Moore, Andrew Goodall, Mark Tibbett, John P Hammond, Elizabeth M H Wellington
In soil, bioavailable inorganic orthophosphate is found at low concentrations and thus limits biological growth. To overcome this phosphorus scarcity, plants and bacteria secrete numerous enzymes, namely acid and alkaline phosphatases, which cleave orthophosphate from various organic phosphorus substrates. Using profile hidden Markov modeling approaches, we investigated the abundance of various non specific phosphatases, both acid and alkaline, in metagenomes retrieved from soils with contrasting pH regimes...
April 16, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28401707/myxobacteria-in-high-moor-and-fen-an-astonishing-diversity-in-a-neglected-extreme-habitat
#5
Kathrin I Mohr, Tanja Zindler, Joachim Wink, Elke Wilharm, Marc Stadler
Increasing antibiotic resistances of numerous pathogens mean that myxobacteria, well known producers of new antibiotics, are becoming more and more interesting. More than 100 secondary metabolites, most of them with bioactivity, were described from the order Myxococcales. Especially new myxobacterial genera and species turned out to be reliable sources for novel antibiotics and can be isolated from uncommon neglected habitats like, for example, acidic soils. Almost nothing is known about the diversity of myxobacteria in moors, except some information from cultivation studies of the 1970s...
April 11, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28397401/anaerobic-utilization-of-fe-iii-xenosiderophores-among-bacteroides-species-and-the-distinct-assimilation-of-fe-iii-ferrichrome-by-bacteroides-fragilis-within-the-genus
#6
Edson R Rocha, Anna S Krykunivsky
In this study, we show that Bacteroides species utilize Fe(III)-xenosiderophores as the only source of exogenous iron to support growth under iron-limiting conditions in vitro anaerobically. Bacteroides fragilis was the only species able to utilize Fe(III)-ferrichrome while Bacteroides vulgatus ATCC 8482 and Bacteroides thetaiotaomicron VPI 5482 were able to utilize both Fe(III)-enterobactin and Fe(III)-salmochelin S4 as the only source of iron in a dose-dependent manner. We have investigated the way B. fragilis assimilates Fe(III)-ferrichrome as initial model to understand the utilization of xenosiderophores in anaerobes...
April 11, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28397370/conservation-and-diversity-of-the-irre-ddro-controlled-radiation-response-in-radiation-resistant-deinococcus-bacteria
#7
Laurence Blanchard, Philippe Guérin, David Roche, Stéphane Cruveiller, David Pignol, David Vallenet, Jean Armengaud, Arjan de Groot
The extreme radiation resistance of Deinococcus bacteria requires the radiation-stimulated cleavage of protein DdrO by a specific metalloprotease called IrrE. DdrO is the repressor of a predicted radiation/desiccation response (RDR) regulon, composed of radiation-induced genes having a conserved DNA motif (RDRM) in their promoter regions. Here, we showed that addition of zinc ions to purified apo-IrrE, and short exposure of Deinococcus cells to zinc ions, resulted in cleavage of DdrO in vitro and in vivo, respectively...
April 11, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28371510/acuc-a-histone-deacetylase-contributes-to-the-pathogenicity-of-aeromonas-hydrophila
#8
Qingling Jiang, Wenbo Chen, Yingxue Qin, Lixing Huang, Xiaojin Xu, Lingmin Zhao, Qingpi Yan
The interactions of pathogens and phagocytes are complex. Our study demonstrated that Aeromonas hydrophila B11 can survive in the macrophagocytes of Tilapia mossambica. To explore the regulatory processes of A. hydrophila survival in the macrophagocytes, we used the mini-Tn10 transposon mutagenesis system to build a mutant library by mixing Escherichia coli Sm10 (pLOFKm) and A. hydrophila B11. In total, 102 mutant colonies were detected, and 11 of them showed reduced survival in macrophagocytes. The mutant with the most severe phenotype, AM73, was chosen for further research...
March 30, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28371280/response-of-the-rhizosphere-prokaryotic-community-of-barley-hordeum-vulgare-l-to-elevated-atmospheric-co2-concentration-in-open-top-chambers
#9
Márton Szoboszlay, Astrid Näther, Esther Mitterbauer, Jürgen Bender, Hans-Joachim Weigel, Christoph C Tebbe
The effect of elevated atmospheric CO2 concentration [CO2 ] on the diversity and composition of the prokaryotic community inhabiting the rhizosphere of winter barley (Hordeum vulgare L.) was investigated in a field experiment, using open-top chambers. Rhizosphere samples were collected at anthesis (flowering stage) from six chambers with ambient [CO2 ] (approximately 400 ppm) and six chambers with elevated [CO2 ] (700 ppm). The V4 region of the 16S rRNA gene was PCR-amplified from the extracted DNA and sequenced on an Illumina MiSeq instrument...
March 30, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28349673/involvement-of-oxidative-stress-in-protocatechuic-acid-mediated-bacterial-lethality
#10
Taofeek O Ajiboye, Ramat S Habibu, Kabiru Saidu, Fatimah Z Haliru, Hikmat O Ajiboye, Najeeb O Aliyu, Oluwayemisi B Ibitoye, Judith N Uwazie, Hamdalat F Muritala, Sharafa A Bello, Idris I Yusuf, Aisha O Mohammed
The involvement of oxidative stress in protocatechuic acid-mediated bacterial lethality was investigated. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) of protocatechuic acid against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus are 600 and 700 μg/ml, 600 and 800 μg/ml, and 600 and 800 μg/ml, respectively. The optical densities and colony-forming units of protocatechuic acid-treated bacteria decreased in time-dependent manner. Protocatechuic acid (4× MIC) significantly increased the superoxide anion content of E...
March 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28349670/metabolic-engineering-to-expand-the-substrate-spectrum-of-pseudomonas-putida-toward-sucrose
#11
Hannes Löwe, Lukas Schmauder, Karina Hobmeier, Andreas Kremling, Katharina Pflüger-Grau
Sucrose is an important disaccharide used as a substrate in many industrial applications. It is a major component of molasses, a cheap by-product of the sugar industry. Unfortunately, not all industrially relevant organisms, among them Pseudomonas putida, are capable of metabolizing sucrose. We chose a metabolic engineering approach to circumvent this blockage and equip P. putida with the activities necessary to consume sucrose. Therefore, we constructed a pair of broad-host range mini-transposons (pSST - sucrose splitting transposon), carrying either cscA, encoding an invertase able to split sucrose into glucose and fructose, or additionally cscB, encoding a sucrose permease...
March 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28349658/revision-and-reannotation-of-the-halomonas-elongata-dsm-2581-t-genome
#12
Friedhelm Pfeiffer, Irina Bagyan, Gabriela Alfaro-Espinoza, Maria-A Zamora-Lagos, Bianca Habermann, Alberto Marin-Sanguino, Dieter Oesterhelt, Hans J Kunte
The genome of the Halomonas elongata type strain DSM 2581, an industrial producer, was reevaluated using the Illumina HiSeq2500 technology. To resolve duplication-associated ambiguities, PCR products were generated and sequenced. Outside of duplications, 72 sequence corrections were required, of which 24 were point mutations and 48 were indels of one or few bases. Most of these were associated with polynucleotide stretches (poly-T stretch overestimated in 19 cases, poly-C underestimated in 15 cases). These problems may be attributed to using 454 technology for original genome sequencing...
March 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28349644/changes-to-cholesterol-trafficking-in-macrophages-by-leishmania-parasites-infection
#13
Geo Semini, Daniel Paape, Athina Paterou, Juliane Schroeder, Martin Barrios-Llerena, Toni Aebischer
Leishmania spp. are protozoan parasites that are transmitted by sandfly vectors during blood sucking to vertebrate hosts and cause a spectrum of diseases called leishmaniases. It has been demonstrated that host cholesterol plays an important role during Leishmania infection. Nevertheless, little is known about the intracellular distribution of this lipid early after internalization of the parasite. Here, pulse-chase experiments with radiolabeled cholesteryl esterified to fatty acids bound to low-density lipoproteins indicated that retention of this source of cholesterol is increased in parasite-containing subcellular fractions, while uptake is unaffected...
March 27, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28332311/characterization-of-blue-light-irradiation-effects-on-pathogenic-and-nonpathogenic-escherichia-coli
#14
Courtney M Abana, John R Brannon, Rebecca A Ebbott, Taryn L Dunigan, Kirsten R Guckes, Hubaida Fuseini, Jennifer Powers, Bridget R Rogers, Maria Hadjifrangiskou
Blue light irradiation (BLI) is an FDA-approved method for treating certain types of infections, like acne, and is becoming increasingly attractive as an antimicrobial strategy as the prevalence of antibiotic-resistant "superbugs" rises. However, no study has delineated the effectiveness of BLI throughout different bacterial growth phases, especially in more BLI-tolerant organisms such as Escherichia coli. While the vast majority of E. coli strains are nonpathogenic, several E. coli pathotypes exist that cause infection within and outside the gastrointestinal tract...
March 22, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28326685/hugonella-massiliensis-gen-nov-sp-nov-genome-sequence-and-description-of-a-new-strictly-anaerobic-bacterium-isolated-from-the-human-gut
#15
Ziena Elsawi, Amadou Hamidou Togo, Mamadou Beye, Grégory Dubourg, Claudia Andrieu, Nicholas Armsrtong, Magali Richez, Fabrizio di Pinto, Fadi Bittar, Noémie Labas, Pierre-Edouard Fournier, Didier Raoult, Saber Khelaifia
The human gut is composed of a large diversity of microorganisms, which have been poorly described. Here, using culturomics, a new concept based on the variation in culture conditions and MALDI-TOF MS identification, we proceed to explore the microbial diversity of the complex ecosystem of the human gut. Using this approach, we isolated strain AT8(T) (=CSUR P2118 =  DSM 101782) from stool specimens collected from a 51-year-old obese French woman. Strain AT8(T) is a strictly anaerobic, nonmotile, nonspore-forming gram-positive coccus that do not exhibit catalase and oxidase activities...
March 21, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28318117/transcriptional-regulation-of-cpsq-mfpabc-and-mfpabc-by-calr%C3%A2-in-vibrio-parahaemolyticus
#16
He Gao, Lingyu Zhang, George Osei-Adjei, Wenhui Yang, Dongsheng Zhou, Xinxiang Huang, Huiying Yang, Zhe Yin, Yiquan Zhang
The cpsQ-mfpABC locus is transcribed as two operons, i.e., cpsQ-mfpABC and mfpABC, in Vibrio parahaemolyticus, and both of them are all required for biofilm formation. CalR belongs to the LysR-type transcriptional regulator family, and was originally identified as a repressor of the swarming motility and T3SS1 genes expression in V. parahaemolyticus. In the present work, a combination of qRT-PCR, primer extension, LacZ fusion expression, electrophoretic mobility shift assay, and DNase I footprinting assays were employed to elucidate the regulatory mechanisms of cpsQ-mfpABC and mfpABC by CalR...
March 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28318115/microbial-players-and-processes-involved-in-phytoplankton-bloom-utilization-in-the-water-column-of-a-fast-flowing-river-dominated-estuary
#17
Maria W Smith, Lydie Herfort, Caroline S Fortunato, Byron C Crump, Holly M Simon
Fueled by seasonal phytoplankton blooms, the Columbia River estuary is a natural bioreactor for organic matter transformations. Prior metagenome analyses indicated high abundances of diverse Bacteroidetes taxa in estuarine samples containing phytoplankton. To examine the hypothesis that Bacteroidetes taxa have important roles in phytoplankton turnover, we further analyzed metagenomes from water collected along a salinity gradient at 0, 5, 15, 25, and 33 PSU during bloom events. Size fractions were obtained by using a 3-μm prefilter and 0...
March 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28317294/comparative-genome-analysis-reveals-important-genetic-differences-among-serotype-o1-and-serotype-o2-strains-of-y-%C3%A2-ruckeri-and-provides-insights-into-host-adaptation-and-virulence
#18
Desirée Cascales, José A Guijarro, Ana I García-Torrico, Jessica Méndez
Despite the existence of a commercial vaccine routinely used to protect salmonids against Yersinia ruckeri, outbreaks still occur, mainly caused by nonmotile and lipase-negative strains (serotype O1 biotype 2). Moreover, epizootics caused by other uncommon serotypes have also been reported. At the moment, one of the main concerns for the aquaculture industry is the expanding range of hosts of this pathogen and the emergence of new biotypes and serotypes causing mortality in fish farms and against which the vaccine cannot protect...
March 20, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28303666/is-the-methanogenic-community-reflecting-the-methane-emissions-of-river-sediments-comparison-of-two-study-sites
#19
Prem Prashant Chaudhary, Martin Rulík, Martin Blaser
Studies on methanogenesis from freshwater sediments have so far primarily focused on lake sediments. To expand our knowledge on the community composition of methanogenic archaea in river sediments, we studied the abundance and diversity of methanogenic archaea at two localities along a vertical profile (top 50 cm) obtained from sediment samples from Sitka stream (the Czech Republic). In this study, we compare two sites which previously have been shown to have a 10-fold different methane emission. Archaeal and methanogen abundance were analyzed by real-time PCR and T-RFLP...
March 16, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28299913/endophytic-fungi-harbored-in-the-root-of-sophora-tonkinensis-gapnep-diversity-and-biocontrol-potential-against-phytopathogens
#20
Yu Qun Yao, Fang Lan, Yun Ming Qiao, Ji Guang Wei, Rong Shao Huang, Liang Bo Li
This work, for the first time, investigated the diversity of endophytic fungi harbored in the xylem and phloem of the root of Sophora tonkinensis Gapnep from three geographic localities with emphasis on the influence of the tissue type and geographic locality on endophytic fungal communities and their potential as biocontrol agents against phytopathogens of Panax notoginseng. A total of 655 fungal strains representing 47 taxa were isolated. Forty-two taxa (89.4%) were identified but not five taxa (10.6%) according to morphology and molecular phylogenetics...
March 15, 2017: MicrobiologyOpen
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