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Applied and Environmental Microbiology

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https://www.readbyqxmd.com/read/29330191/thermophilic-alkaline-fermentation-followed-by-mesophilic-anaerobic-digestion-for-efficient-hydrogen-and-methane-production-from-waste-activated-sludge-focusing-on-dynamics-of-bacterial-pathogens-as-revealed-by-the-combination-of-metagenomic-and-qpcr-analysis
#1
Jingjing Wan, Yuhang Jing, Yue Rao, Shicheng Zhang, Gang Luo
Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste activated sludge (WAS) was investigated. TM process was also compared to mesophilic alkaline fermentation followed by mesophilic anaerobic digestion (MM) process and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 mLH2/gVS) and methane yield (150.7 mLCH4/gVS) in TM process were higher than those (6.7 mLH2/gVS and 127.8 mLCH4/gVS) in MM process...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330190/influence-of-pig-farming-on-the-human-s-nasal-microbiota-the-key-role-of-the-airborne-microbial-communities
#2
Julia G Kraemer, Alban Ramette, Suzanne Aebi, Anne Oppliger, Markus Hilty
It has been hypothesized that the environment can influence the composition of the nasal microbiota. However, the direct influence of pig farming on the anterior and posterior nasal microbiota is unknown. Using a cross-sectional design, pig farms (n=28) were visited in 2014-2015 and nasal swabs from 43 pig farmers and 56 pigs as well as 27 air samples taken in the vicinity of pig enclosure were collected. As controls, nasal swabs from 17 cow farmers and 26 non-animal exposed individuals were also included. Analyses of the microbiota were performed based on 16S rRNA amplicon sequencing and the DADA2 pipeline to define sequence variants (SVs)...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330189/targeted-synthesis-and-characterization-of-a-gene-cluster-encoding-nad-p-h-dependent-3%C3%AE-3%C3%AE-and-12%C3%AE-hydroxysteroid-dehydrogenases-from-eggerthella-cag-298-a-gut-metagenomic-sequence
#3
Sean M Mythen, Saravanan Devendran, Celia Méndez-García, Isaac Cann, Jason M Ridlon
Gut metagenomic sequences provide a rich source of microbial genes, the majority of which are annotated by homology or unknown. Genes and gene pathways that encode enzymes catalyzing biotransformation of host bile acids are important to identify in gut metagenomic sequences due to the importance of bile acids on gut microbiome structure and host physiology. Hydroxysteroid dehydrogenases (HSDH) are pyridine nucleotide-dependent enzymes with stereo-specificity and regio-specificity for bile acid and steroid hydroxyl groups...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330188/germination-outgrowth-and-vegetative-growth-kinetics-of-dry-heat-treated-individual-spores-of-bacillus-species
#4
Lin He, Zhan Chen, Shiwei Wang, Muying Wu, Peter Setlow, Yong-Qing Li
DNA damage kills dry-heated spores of Bacillus subtilis, but dry heat-treatment effects on spore germination and outgrowth have not been studied. This is important, since if dry heat-killed spores germinate and undergo outgrowth, toxic proteins could be synthesized. Here, Raman spectroscopy and differential interference contrast microscopy were used to study germination and outgrowth of individual dry heat-treated B. subtilis and Bacillus megaterium spores. Major findings in this work were as follows. 1) Spores dry heat-treated at 140°C for 20 min nearly all lost viability but retained their Ca2+-dipicolinic acid (CaDPA) depot...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330187/acquisition-of-a-novel-sulfur-oxidizing-symbiont-in-the-gutless-marine-worm-inanidrilus-exumae
#5
C Bergin, C Wentrup, N Brewig, A Blazejak, C Erséus, O Giere, M Schmid, P De Wit, N Dubilier
Gutless phallodrilines are marine annelid worms without a mouth or gut, which live in an obligate association with multiple bacterial endosymbionts that supply them with nutrition. In this study, we discovered an unusual symbiont community in the gutless phallodriline Inanidrilus exumae that differs markedly from the microbiome of all other 22 examined host species. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization revealed that I. exumae harboured co-occurring gamma-, alpha- and deltaproteobacterial symbionts, while all other known host species harbour gamma- and either alpha- or deltaproteobacterial symbionts...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330186/effect-of-plasmid-design-and-type-of-integration-event-on-recombinant-protein-expression-in-pichia-pastoris
#6
Thomas Vogl, Leigh Gebbie, Robin W Palfreyman, Robert Speight
Pichia pastoris (syn. Komagataella phaffii) is one of the most common eukaryotic expression systems for heterologous protein production. Expression cassettes are typically integrated in the genome to obtain stable expression strains. In contrast to Saccharomyces cerevisiae, where short overhangs are sufficient to target highly specific integration, long overhangs are more efficient in P. pastoris and ectopic integration of foreign DNA can occur. Here, we aimed to elucidate the influence of ectopic integration by high throughput screening of >700 transformants and whole genome sequencing of 27 transformants...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330185/the-mgte-homolog-fici-acts-as-a-secondary-ferrous-iron-importer-in-shewanella-oneidensis-strain-mr-1
#7
Brittany D Bennett, Kaitlyn E Redford, Jeffrey A Gralnick
The transport of metals into and out of cells is necessary for the maintenance of appropriate intracellular concentrations. Metals are needed for incorporation into metalloproteins but become toxic at higher concentrations. Many metal transport proteins have been discovered in bacteria, including the Mg2+ transporter-E (MgtE) family of passive Mg2+/Co2+ cation-selective channels. Low sequence identity exists between members of the MgtE family, indicating that substrate specificity may differ among MgtE transporters...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330184/microbiomes-in-dishwashers-analysis-of-the-microbial-diversity-and-putative-opportunistic-pathogens-in-dishwasher-biofilm-communities
#8
Prem Krishnan Raghupathi, Jerneja Zupančič, Asker Daniel Brejnrod, Samuel Jacquiod, Kurt Houf, Mette Burmølle, Nina Gunde-Cimerman, Søren J Sørensen
Extreme habitats are not only limited to natural environments, but also apply to man-made systems, for instance household appliances such as dishwashers. Limiting factors, such as high temperatures, high and low pH, high NaCl concentrations, presence of detergents and shear force from water during washing cycles define the microbial survival in this extreme system. Fungal and bacterial diversity in biofilms isolated from rubber seals of 24 different household dishwashers were investigated using next generation sequencing...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330183/campylobacter-jejuni-colonization-in-the-crow-gut-involves-high-deletion-within-the-cytolethal-distending-toxin-gene-cluster
#9
Keya Sen, Jingrang Lu, Piyali Mukherjee, Tanner Berglund, Eunice Varughese, Asish K Mukhopadhyay
Campylobacter spp. are major causes of gastroenteritis worldwide. The virulence potential of Campylobacter shed in crow feces obtained from a roost area in Bothell, Washington, was studied and compared with isolates from other parts of Washington, and from a different crow spp., 7000 miles away, in Kolkata, India. Campylobacter was isolated from 61% and 69 % of the fecal samples obtained from Washington and Kolkata, respectively and were confirmed to be C. jejuni The cytolethal distending toxin (CDT) gene cluster from these isolates revealed a truncated sequence of about 1400 bp...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330182/fluorescence-recovery-allows-the-implementation-of-a-fluorescence-reporter-gene-platform-applicable-for-the-detection-and-quantification-of-horizontal-gene-transfer-in-anoxic-environments
#10
Rafael Pinilla, Leise Riber, Søren J Sørensen
The study of horizontal gene transfer (HGT) in microbial communities has been revolutionized by significant advances in cultivation-independent methods based on fluorescence reporter gene technologies. Recently, the combination of these novel approaches with flow cytometry has presented itself as one of the most powerful tools to study the spread of mobile genetic elements (MGEs) in the environment. However, the use of fluorescent markers like green fluorescent protein (GFP) and mCherry is limited by environmental constraints that affect the correct maturation of their fluorophores, such as oxygen availability and pH levels...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330181/a-novel-l-glutamate-exporter-of-corynebacterium-glutamicum
#11
Yu Wang, Guoqiang Cao, Deyu Xu, Liwen Fan, Xinyang Wu, Xiaomeng Ni, Shuxin Zhao, Ping Zheng, Jibin Sun, Yanhe Ma
Besides metabolic pathways and regulatory networks, transport systems are also pivotal for cellular metabolism and hyper-production of biochemicals using microbial cell factories. Identification and characterization of transporters are therefore of great significance for understanding and engineering of transport reactions. Herein, a novel l-glutamate exporter MscCG2 that extensively exists in Corynebacterium glutamicum strains but is distinct from the only known l-glutamate exporter MscCG was discovered in an industrial l-glutamate producing C...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330180/genomic-and-phenotypic-characterization-of-type-strains-and-dairy-associated-isolates-in-the-bacillus-cereus-group-indicates-considerable-intra-clade-variability-in-toxin-production-and-cytotoxicity
#12
Rachel A Miller, Jiahui Jian, Sarah M Beno, Martin Wiedmann, Jasna Kovac
While some species in the B. cereus group are well-characterized human pathogens (e.g., B. anthracis and B. cereus s.s.), the pathogenicity of other species (e.g., B. pseudomycoides) either has not been characterized or is presently not well understood. To provide an updated characterization of the pathogenic potential of species in the B. cereus group, we classified a set of 52 isolates, including 8 type strains and 44 environmental isolates from dairy-associated sources, into 7 phylogenetic clades and characterized them for (i) the presence of toxin genes, (ii) phenotypic characteristics used for identification, and (iii) cytotoxicity to human epithelial cells...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330179/influence-of-type-i-fimbriae-and-fluid-shear-stress-on-bacterial-behavior-and-multicellular-architecture-of-early-escherichia-coli-biofilms-at-single-cell-resolution
#13
Liyun Wang, Robert Keatch, Qi Zhao, John A Wright, Clare E Bryant, Anna L Redmann, Eugene M Terentjev
Biofilm formation on abiotic surfaces in food and medical industry can cause severe contamination and infection, yet how biological and physical factors determine cellular architecture of early biofilms and bacterial behavior of the constituent cells remains largely unknown. In this study we examine the specific role of type-I fimbriae in nascent stages of biofilm formation and the response of micro-colonies to environmental flow shear at single-cell resolution. The results show that type-I fimbriae are not required for reversible adhesion from plankton, but critical for irreversible adhesion of Escherichia coli (E...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330178/development-of-an-efficient-genome-editing-tool-in-bacillus-licheniformis-using-crispr-cas9-nickase
#14
Kaifeng Li, Dongbo Cai, Zhangqian Wang, Zhili He, Shouwen Chen
Bacillus strains are important industrial bacteria that can produce various biochemical products. However, low transformation efficiencies and a lack of effective genome editing tools have hindered its widespread application. Recently, clustered regularly interspaced short palindromic repeat (CRISPR)/cas9 techniques have been utilized in many organisms as genome editing tools because of their high efficiency and easy manipulation. In this study, an efficient genome editing method was developed for Bacillus licheniformis using a CRISPR-Cas9 nickase integrated into the genome of B...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29330177/incidence-of-facultative-bacterial-endosymbionts-in-spider-mites-associated-with-local-environment-and-host-plant
#15
Yu-Xi Zhu, Yue-Ling Song, Yan-Kai Zhang, Ary A Hoffmann, Jin-Cheng Zhou, Jing-Tao Sun, Xiao-Yue Hong
Spider mites are frequently associated with multiple endosymbionts whose infection patterns often exhibit spatial and temporal variation. However, the association between endosymbiont prevalence and environmental factors remains unclear. Here, we surveyed endosymbionts in natural populations of the spider mite, Tetranychus truncatus, in China, screening 935 spider mites from 21 localities and 12 host plant species. Three facultative endosymbiont lineages, Wolbachia, Cardinium, and Spiroplasma, were detected at different infection frequencies (52...
January 12, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29305515/sapovirus-in-wastewater-treatment-plants-in-tunisia-prevalence-removal-and-genetic-characterization
#16
Miguel F Varela, Imen Ouardani, Tsuyoshi Kato, Syunsuke Kadoya, Mahjoub Aouni, Daisuke Sano, Jesús L Romalde
Sapovirus (SaV), from the Caliciviridae family, are enteric viruses that cause acute gastroenteritis. SaV are shed at high concentrations with faeces to wastewater, which are usually discharged at the aquatic environments or reused for irrigation without efficient treatments. This study analyzed the incidence of human SaV in four wastewater treatment plants from Tunisia during a period of 13 months (December 2009 to December 2010). Detection and quantification were carried out using RT-qPCR methods, obtaining a prevalence of 39...
January 5, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29305514/metals-and-methanotrophy
#17
Jeremy D Semrau, Alan A DiSpirito, Wenyu Gu, Sukhwan Yoon
Aerobic methanotrophs have long been known to play a critical role in the global carbon cycle, capable of converting methane to biomass and carbon dioxide. Interestingly, these microbes exhibit great sensitivity to copper and rare earth elements, with expression of key genes involved in the central pathway of methane oxidation controlled by the availability of these metals. That is, these microbes have a "copper-switch" that controls expression of alternative methane monooxygenases and a "rare earth element-switch" that controls expression of alternative methanol dehydrogenases...
January 5, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29305513/production-of-4-hydroxybenzoic-acid-by-an-aerobic-growth-arrested-bioprocess-using-metabolically-engineered-corynebacterium-glutamicum
#18
Yukihiro Kitade, Ryoma Hashimoto, Masako Suda, Kazumi Hiraga, Masayuki Inui
Corynebacterium glutamicum was metabolically engineered to produce 4-hydroxybenzoic acid (4-HBA), a valuable aromatic compound used as a raw material for the production of liquid crystal polymers and paraben. C. glutamicum was found to have a higher tolerance to 4-HBA toxicity than previously reported hosts used for the production of genetically engineered 4-HBA. To obtain higher titers of 4-HBA, we employed a stepwise overexpression of all seven target genes in the shikimate pathway in C. glutamicum Specifically, multiple chromosomal integrations of a mutated aroG from Escherichia coli, encoding a DAHP synthase, and wild-type aroCKB from C...
January 5, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29305512/molecular-epidemiology-of-dairy-cattle-associated-escherichia-coli-carrying-blactx-m-genes-in-washington-state
#19
Josephine A Afema, Sara Ahmed, Thomas E Besser, Lisa P Jones, William M Sischo, Margaret A Davis
An increase in prevalence of commensal Escherichia coli carrying blaCTX-M genes among dairy cattle was observed between 2008 and 2012 in Washington State. To study the molecular epidemiology of this change, we selected 126 blaCTX-M-positive and 126 blaCTX-M-negative isolates for multi-locus sequence typing (MLST) and antibiotic resistance phenotyping from E. coli obtained during a previous study. For 99 isolates we also determined the blaCTX-M alleles using PCR and sequencing and identified the replicon types of blaCTX-M carrying plasmids...
January 5, 2018: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29305511/a-cytoplasmic-antiholin-is-embedded-in-frame-with-the-holin-in-a-lactobacillus-fermentum-bacteriophage
#20
Tingting Guo, Yongping Xin, Chenchen Zhang, Jian Kong
In double-stranded DNA bacteriophages, infection cycles are ended by host cell lysis through the action of phage-encoded endolysins and holins. The precise timing of lysis is regulated by the holin inhibitors, named antiholins. Sequence analysis has revealed that holins with a single transmembrane domain (TMD) are prevalent in Lactobacillus bacteriophages. A temperate bacteriophage of Lbfermentum, ϕPYB5, has a two-component lysis cassette containing endolysin Lyb5 and holin Hyb5. The hyb5 gene is 465-bp long, encoding 154 amino acid residues with an N-terminal TMD and a large cytoplasmic C-terminal domain...
January 5, 2018: Applied and Environmental Microbiology
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