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https://www.readbyqxmd.com/read/28549325/graphene-oxide-in-the-water-environment-could-affect-tetracycline-antibiotic-resistance
#1
Mei-Ting Guo, Guo-Sheng Zhang
In recent years, the influence of new materials like nanoparticles in the water environment on biological substances has been widely studied. Antibiotic resistance genes (ARGs) represent a new type of pollutant in the environment. Graphene oxide (GO), as a nano material, because of its unique structure, may have an impact on antibiotic resistance bacteria (ARB) and ARGs; however the research in this area is rarely reported. Therefore, this study mainly investigated the effects of GO on bacterial antibiotic resistance...
May 3, 2017: Chemosphere
https://www.readbyqxmd.com/read/28547727/isolation-purification-and-chemical-characterization-of-a-new-angucyclinone-compound-produced-by-a-new-halotolerant-nocardiopsis-sp-hr-4-strain
#2
Yamina Hadj Rabia-Boukhalfa, Yannick Eveno, Solange Karama, Okba Selama, Béatrice Lauga, Robert Duran, Hocine Hacène, Véronique Eparvier
A halotolerant Actinobacteria strain HR-4 was isolated from a salt lake soil sample in Algerian Sahara. Analysis of 16S rDNA gene sequence showed that strain HR-4 belonged to the genus Nocardiopsis. The similarity level ranges between 97.45 and 99.20% with Nocardiopsis species and Nocardiopsis rosea being the most closely related one. Morphological, physiological and phylogenetic characteristics comparisons showed significant differences with the nearest species. These data strongly suggest that strain HR-4 represents novel species...
June 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28547376/nonribosomal-peptides-and-polyketides-of-burkholderia-new-compounds-potentially-implicated-in-biocontrol-and-pharmaceuticals
#3
Qassim Esmaeel, Maude Pupin, Philippe Jacques, Valérie Leclère
Bacteria belonging to the genus Burkholderia live in various ecological niches and present a significant role in the environments through the excretion of a wide variety of secondary metabolites including modular nonribosomal peptides (NRPs) and polyketides (PKs). These metabolites represent a widely distributed biomedically and biocontrol important class of natural products including antibiotics, siderophores, and anticancers as well as biopesticides that are considered as a novel source that can be used to defend ecological niche from competitors and to promote plant growth...
May 25, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28546842/opportunities-and-challenges-for-the-sustainable-production-of-structurally-complex-diterpenoids-in-recombinant-microbial-systems
#4
REVIEW
Katarina Kemper, Max Hirte, Markus Reinbold, Monika Fuchs, Thomas Brück
With over 50.000 identified compounds terpenes are the largest and most structurally diverse group of natural products. They are ubiquitous in bacteria, plants, animals and fungi, conducting several biological functions such as cell wall components or defense mechanisms. Industrial applications entail among others pharmaceuticals, food additives, vitamins, fragrances, fuels and fuel additives. Central building blocks of all terpenes are the isoprenoid compounds isopentenyl diphosphate and dimethylallyl diphosphate...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28546547/bioturbation-as-a-key-driver-behind-the-dominance-of-bacteria-over-archaea-in-near-surface-sediment
#5
Xihan Chen, Thorbjørn Joest Andersen, Yuki Morono, Fumio Inagaki, Bo Barker Jørgensen, Mark Alexander Lever
The factors controlling the relative abundances of Archaea and Bacteria in marine sediments are poorly understood. We determined depth distributions of archaeal and bacterial 16S rRNA genes by quantitative PCR at eight stations in Aarhus Bay, Denmark. Bacterial outnumber archaeal genes 10-60-fold in uppermost sediments that are irrigated and mixed by macrofauna. This bioturbation is indicated by visual observations of sediment color and faunal tracks, by porewater profiles of dissolved inorganic carbon and sulfate, and by distributions of unsupported (210)Pb and (137)Cs...
May 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28546214/rna-polymerase-motions-during-promoter-melting
#6
Andrey Feklistov, Brian Bae, Jesse Hauver, Agnieszka Lass-Napiorkowska, Markus Kalesse, Florian Glaus, Karl-Heinz Altmann, Tomasz Heyduk, Robert Landick, Seth A Darst
All cellular RNA polymerases (RNAPs), from those of bacteria to those of man, possess a clamp that can open and close, and it has been assumed that the open RNAP separates promoter DNA strands and then closes to establish a tight grip on the DNA template. Here, we resolve successive motions of the initiating bacterial RNAP by studying real-time signatures of fluorescent reporters placed on RNAP and DNA in the presence of ligands locking the clamp in distinct conformations. We report evidence for an unexpected and obligatory step early in the initiation involving a transient clamp closure as a prerequisite for DNA melting...
May 26, 2017: Science
https://www.readbyqxmd.com/read/28546025/molecular-and-functional-characterization-of-a-glycosylated-galactose-binding-lectin-from-mytilus-californianus
#7
Efrén García-Maldonado, Patricia Cano-Sánchez, Alejandra Hernández-Santoyo
Lectins play crucial roles for innate immune responses in invertebrates by recognizing and eliminating pathogens. In this study, a lectin from the mussel Mytilus californianus (MCL) was identified and characterized. The lectin was purified by affinity chromatography in α-lactose-agarose resin showing an experimental molecular weight of 18000 Da as determined by SDS-PAGE and MALDI-TOF mass spectrometry. It was specific for binding d-galactose and N-Acetyl-d-galactosamine that contained carbohydrate moieties that were also inhibited by melibiose and raffinose...
May 22, 2017: Fish & Shellfish Immunology
https://www.readbyqxmd.com/read/28545669/are-russian-propolis-ethanol-extracts-the-future-for-the-prevention-of-medical-and-biomedical-implant-contaminations
#8
Ashwin Ambi, Julia Bryan, Katherine Borbon, Daniel Centeno, Tianchi Liu, Tung Po Chen, Thomas Cattabiani, Christian Traba
BACKGROUND: Most studies reveal that the mechanism of action of propolis against bacteria is functional rather than structural and is attributed to a synergism between the compounds in the extracts. HYPOTHESIS/PURPOSE: Propolis is said to inhibit bacterial adherence, division, inhibition of water-insoluble glucan formation, and protein synthesis. However, it has been shown that the mechanism of action of Russian propolis ethanol extracts is structural rather than functional and may be attributed to the metals found in propolis...
July 1, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/28545305/clostridium-difficile-toxins-a-and-b-receptors-pores-and-translocation-into-cells
#9
Kathleen E Orrell, Zhifen Zhang, Seiji N Sugiman-Marangos, Roman A Melnyk
The most potent toxins secreted by pathogenic bacteria contain enzymatic moieties that must reach the cytosol of target cells to exert their full toxicity. Toxins such as anthrax, diphtheria, and botulinum toxin all use three well-defined functional domains to intoxicate cells: a receptor-binding moiety that triggers endocytosis into acidified vesicles by binding to a specific host-cell receptor, a translocation domain that forms pores across the endosomal membrane in response to acidic pH, and an enzyme that translocates through these pores to catalytically inactivate an essential host cytosolic substrate...
May 26, 2017: Critical Reviews in Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28545259/identification-of-diacetonamine-from-soybean-curd-residue-as-a-sporulation-inducing-factor-toward-bacillus-spp
#10
Aki Ikeda, Dongyeop Kim, Yasuyuki Hashidoko
Under bioassay-guided investigation, a sporulation-inducing factor (SIF) toward Bacillus spp. was searched for in methanol (MeOH) extracts of soybean curd residues, and diacetonamine (1) was identified as the active compound. SIF was first isolated as a monoacetylated derivative (2, 4.1 mg from 655 g soybean curd residues), and its chemical structure was elucidated by field desorption mass spectrometry, electron ionization mass spectrometry, and nuclear magnetic resonance (NMR) analyses. After 48-h incubation, 40 µM diacetonamine hydrochloride (1b) exhibited sporulation-inducing activity with 35% sporulation frequency toward a Bacillus amyloliquefaciens wild-type strain (AHU 2170), whereas 40 µM diacetone acrylamide (3) showed 99% sporulation induction, which was much higher than that of 1b...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28544612/ecology-adaptation-and-function-of-methane-sulfidic-spring-water-biofilm-microorganisms-including-a-strain-of-anaerobic-fungus-mucor-hiemalis
#11
Enamul Hoque, Johannes Fritscher
Ecological aspects, adaptation, and some functions of a special biofilm and its unique key anaerobic fungus Mucor hiemalis strain EH11 isolated from a pristine spring (Künzing, Bavaria, Germany) are described. The spring's pure nature is characterized by, for example, bubbling methane, marine-salinity, mild hydrothermal (~19.1°C), sulfidic, and reductive-anoxic (Eh : -241 to -253 mV, O2 : ≤ 0.1 mg/L) conditions. It is geoecologically located at the border zone between Bavarian Forest (crystalline rocky mountains) and the moor-like Danube River valley, where geological displacements bring the spring's water from the deeper layers of former marine sources up to the surface...
May 24, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28544290/organic-co-prodrugs-structure-co-release-rate-relationship-studies
#12
Binghe Wang, Zhixiang Pan, Xingyue Ji, Vayou Chittavong, Wei Li, Kaili Ji, Mengyuan Zhu, Jun Zhang
Carbon monoxide (CO) is an endogenously produced gasotransmitter in mammals, and may have signaling roles in bacteria as well. It has many recognized therapeutic effects. A significant challenge in this field is the development of pharmaceutically acceptable forms of CO delivery with controllable and tunable release rates. Herein, we describe the structure-release rate studies of the first class of organic CO-prodrugs that release CO in aqueous solution at neutral pH.
May 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28544098/crystal-structure-of-the-sensor-domain-of-baes-from-serratia-marcescens-fs14
#13
Ya Zhang, Shenshen Qiu, Shanshan Jia, Dongqing Xu, Tingting Ran, Weiwu Wang
The sensor histidine kinases of two-component signal-transduction systems (TCSs) are essential for bacteria to adapt to variable environmental conditions. The two-component regulatory system BaeS/R increases multidrug and metal resistance in Salmonella and Escherichia coli. In this study, we report the X-ray structure of the periplasmic sensor domain of BaeS from Serratia marcescens FS14. The BaeS sensor domain (34-160) adopts a mixed α/β-fold containing a central four-stranded antiparallel β-sheet flanked by a long N-terminal α-helix and additional loops and a short C-terminal α-helix on each side...
May 24, 2017: Proteins
https://www.readbyqxmd.com/read/28543534/a-chimeric-protein-of-cfa-i-cs6-subunits-and-ltb-sta-toxoid-could-protect-immunized-mice-against-enterotoxigenic-escherichia-coli
#14
Narges Zeinalzadeh, Ali Hatef Salmanian, Goli Goujani, Jafar Amani, Ghasem Ahangari, Asal Akhavian, Mahyat Jafari
Enterotoxigenic Escherichia Coli (ETEC) strains are the most common bacteria causing diarrhea in children in developing countries and travelers to these areas. Colonization factors (CFs) and enterotoxins are the main virulence determinants in ETEC pathogenesis. Heterogeneity of CFs commonly considered as the bottleneck to achieve an effective vaccine. On the other hand, it is believed that a broad spectrum protection against ETEC would be available when the anti-CF and anti-enterotoxin immunity were induced simultaneously...
May 23, 2017: Microbiology and Immunology
https://www.readbyqxmd.com/read/28542634/crystallographic-characterization-of-the-high-potential-iron-sulfur-protein-in-the-oxidized-state-at-0-8-%C3%A3-resolution
#15
Hiraku Ohno, Kazuki Takeda, Satomi Niwa, Tomotaka Tsujinaka, Yuya Hanazono, Yu Hirano, Kunio Miki
High-potential iron-sulfur protein (HiPIP) is a soluble electron carrier protein of photosynthetic bacteria with an Fe4S4 cluster. Although structural changes accompanying the electron transfer are important for understanding of the functional mechanism, the changes have not been clarified in sufficient detail. We previously reported the high-resolution crystal structures of HiPIP from a thermophilic purple bacterium Thermochromatium tepidum in the reduced state. In order to perform a detailed comparison between the structures in different redox states, the oxidized structure should also be revealed at high resolution...
2017: PloS One
https://www.readbyqxmd.com/read/28542542/comparative-analysis-of-bacterial-community-structure-in-the-rhizosphere-of-maize-by-high-throughput-pyrosequencing
#16
Yi Yang, Na Wang, Xinyan Guo, Yi Zhang, Boping Ye
In this study, we designed a microcosm experiment to explore the composition of the bacterial community in the rhizosphere of maize and bulk soil by sequencing the V3-V4 region of the 16S rRNA gene on the Illumina system. 978-1239 OTUs (cut off level of 3%) were found in rhizosphere and bulk soil samples. Rhizosphere shared features with the bulk soil, such as predominance of Acidobacteria, Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Gemmatimonadetes and TM7. At genus level, many of the dominant rhizosphere genera (Chitinophaga, Nitrospira, Flavobacterium, etc...
2017: PloS One
https://www.readbyqxmd.com/read/28542462/a-human-monocytic-nf-%C3%AE%C2%BAb-fluorescent-reporter-cell-line-for-detection-of-microbial-contaminants-in-biological-samples
#17
Claire Battin, Annika Hennig, Patrick Mayrhofer, Renate Kunert, Gerhard J Zlabinger, Peter Steinberger, Wolfgang Paster
Sensing of pathogens by innate immune cells is essential for the initiation of appropriate immune responses. Toll-like receptors (TLRs), which are highly sensitive for various structurally and evolutionary conserved molecules derived from microbes have a prominent role in this process. TLR engagement results in the activation of the transcription factor NF-κB, which induces the expression of cytokines and other inflammatory mediators. The exquisite sensitivity of TLR signalling can be exploited for the detection of bacteria and microbial contaminants in tissue cultures and in protein preparations...
2017: PloS One
https://www.readbyqxmd.com/read/28541183/pausing-guides-rna-folding-to-populate-transiently-stable-rna-structures-for-riboswitch-based-transcription-regulation
#18
Hannah Steinert, Florian Sochor, Anna Wacker, Janina Buck, Christina Helmling, Fabian Hiller, Sara Keyhani, Jonas Noeske, Steffen Kaspar Grimm, Martin M Rudolph, Heiko Keller, Rachel Anne Mooney, Robert Landick, Beatrix Suess, Boris Fürtig, Jens Wöhnert, Harald Schwalbe
In bacteria, the regulation of gene expression by cis-acting transcriptional riboswitches located in the 5'-untranslated regions of messenger RNA requires the temporal synchronization of RNA synthesis and ligand binding-dependent conformational refolding. Ligand binding to the aptamer domain of the riboswitch induces premature termination of the mRNA synthesis of ligand-associated genes due to the coupled formation of 3'-structural elements acting as terminators. To date, there has been no high resolution structural description of the concerted process of synthesis and ligand-induced restructuring of the regulatory RNA element...
May 25, 2017: ELife
https://www.readbyqxmd.com/read/28540925/microorganisms-and-ocean-global-change
#19
REVIEW
David A Hutchins, Feixue Fu
The prokaryotic and eukaryotic microorganisms that drive the pelagic ocean's biogeochemical cycles are currently facing an unprecedented set of comprehensive anthropogenic changes. Nearly every important control on marine microbial physiology is currently in flux, including seawater pH, pCO2, temperature, redox chemistry, irradiance and nutrient availability. Here, we examine how microorganisms with key roles in the ocean carbon and nitrogen cycles may respond to these changes in the Earth's largest ecosystem...
May 25, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28540424/screening-and-optimizing-of-inhibitors-for-ammonia-oxidizing-bacteria-in-sediments-of-malodorous-river
#20
Jianhua Wang, Yan He, Jin Zhu, Huimin Guan, Minsheng Huang
The proper use of selective ammonia-oxidizing archaea (AOA) and/or ammonia-oxidizing bacteria (AOB) inhibitors is critical to distinguish AOA and AOB contribution. In this research, three inhibitors including ampicillin, dicyandiamide (DCD), and allylthiourea (ATU) were examined mainly focusing on inhibiting dosage, adaptability, and effects. The results showed that the optimized inhibitory dosage of ampicillin, DCD, and ATU was separately 1.5 g L(-1), 1 mM, and 25 μM. Among the three inhibitors, ATU exhibited the strongest and persistent inhibition effects and resulted in up to 90% inhibition in the AOB-enriched culture...
May 24, 2017: Applied Microbiology and Biotechnology
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