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Applied and Environmental Microbiology

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https://www.readbyqxmd.com/read/28646115/genome-analysis-of-endomicrobium-proavitum-suggests-loss-and-gain-of-relevant-functions-during-the-evolution-of-intracellular-symbionts
#1
Hao Zheng, Carsten Dietrich, Andreas Brune
Bacterial endosymbionts of eukaryotes show progressive genome erosion, but detailed investigations of the evolutionary processes involved in the transition to an intracellular lifestyle are generally hampered by the lack of extant free-living lineages. Here, we characterize the genome of the recently isolated, free-living Endomicrobium proavitum, the second member of the Elusimicrobia phylum brought into pure culture, and compare it to the closely related "Candidatus Endomicrobium trichonymphae" strain Rs-D17, a previously described but uncultured endosymbiont of termite gut flagellates...
June 23, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28646114/staphylococcus-aureus-strain-newman-photoinactivation-and-cellular-response-to-sunlight-exposure
#2
Jill S McClary, Lauren M Sassoubre, Alexandria B Boehm
Sunlight influences microbial water quality of surface waters. Previous studies have investigated photoinactivation mechanisms and cellular photostress responses of fecal indicator bacteria (FIB), including Escherichia coli and enterococci, but further work is needed to characterize photostress responses of bacterial pathogens. Here we investigate the photoinactivation of Staphylococcus aureus (strain Newman), a pigmented, waterborne pathogen of emerging concern. We measured photodecay using standard culture-based assays and cellular membrane integrity; and investigated photostress response by measuring the relative number of mRNA transcripts of select oxidative stress, DNA repair, and metabolism genes...
June 23, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28646113/aerosolization-of-mycotoxins-after-growth-of-toxinogenic-fungi-on-wallpaper
#3
Brankica Aleksic, Marjorie Draghi, Sebastien Ritoux, Sylviane Bailly, Marlène Lacroix, Isabelle P Oswald, Jean-Denis Bailly, Enric Robine
Many fungi can develop on building material in indoor environments if moisture is high enough. Among species that are frequently observed, some are known to be potent mycotoxin producers. This presence of toxinogenic fungi in indoor environments raises the question of the possible exposure of occupants to these toxic compounds by inhalation after aerosolization.This study investigated the mycotoxin production by Penicillium brevicompactum, Aspergillus versicolor and Stachybotrys chartarum during their growth on wallpaper and the possible subsequent aerosolization of produced mycotoxins from contaminated substrates...
June 23, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28646112/crispr-cas12a-assisted-recombineering-in-bacteria
#4
Mei-Yi Yan, Hai-Qin Yan, Gai-Xian Ren, Ju-Ping Zhao, Xiao-Peng Guo, Yi-Cheng Sun
Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas12a (Cpf1) has emerged as an effective genome editing tool in many organisms. Here, we developed and optimized a CRISPR-Cas12a assisted recombineering system to facilitate genetic manipulation in bacteria. Using this system, point mutations, deletions, insertions, and gene replacements can be easily generated on the chromosome or native plasmids in Escherichia coli, Yersinia pestis, and Mycobacterium smegmatis Because CRISPR-Cas12a-assisted recombineering does not require introduction of an antibiotic resistance gene into the chromosome to select for recombinants, it is an efficient approach for generating markerless and scarless mutations in bacteria...
June 23, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28646111/a-bacillus-paralicheniformis-iron-containing-urease-reduces-urea-concentrations-in-rice-wine
#5
Qingtao Liu, Yuqi Chen, Minglai Yuan, Guocheng Du, Jian Chen, Zhen Kang
Urease, as a nickel-containing metalloenzyme, was the first enzyme to be crystallized, and it has a prominent position in the history of biochemistry. In the present study, we identified a nickel urease gene cluster, ureABCEFGDH, from Bacillus paralicheniformis ATCC 9945a and characterized it in Escherichia coli Enzymatic assays demonstrate that this oxygen-stable urease is also an iron-containing acid urease. UreH heterologous expression assays suggest that this accessory protein is involved in transmembrane transportation of nickel and iron ions...
June 23, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625998/structures-compositions-and-activities-of-live-shewanella-biofilms-formed-on-graphite-electrodes-in-electrochemical-flow-cells
#6
Miho Kitayama, Ryota Koga, Takuya Kasai, Atsushi Kouzuma, Kazuya Watanabe
An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with Shewanella oneidensis MR-1 expressing an anaerobic fluorescence protein, and biofilm formation on WE were observed over time during current generation at WE potentials of +0.4 and 0 V (vs. standard hydrogen electrodes) under electrolyte-flow conditions. Electrochemical analyses suggest the presence of unique electron-transfer mechanisms in the +0.4 V biofilm. Microscopic analyses revealed that, different from aerobic biofilms, current-generating biofilm (at +0...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625997/quantifying-vibrio-cholerae-enterotoxicity-in-a-zebrafish-infection-model
#7
Kristie C Mitchell, Paul Breen, Sarah Britton, Melody N Neely, Jeffrey H Withey
Vibrio cholerae is the etiological agent of cholera, an acute intestinal infection in humans characterized by voluminous watery diarrhea. Cholera is spread through ingestion of contaminated food or water, primarily in developing countries that lack the proper infrastructure for proper water and sewage treatment. Vibrio cholerae is an aquatic bacterium that inhabits coastal and estuarine areas, and is known to have several environmental reservoirs, including fish. Our laboratory has recently described the use of the zebrafish as a new animal model for the study of V...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625996/natural-dna-transformation-is-functional-in-lactococcus-lactis-ssp-cremoris-kw2
#8
Blandine David, Amandine Radziejwoski, Frédéric Toussaint, Laetitia Fontaine, Marie Henry de Frahan, Cédric Patout, Sabine van Dillen, Patrick Boyaval, Philippe Horvath, Christophe Fremaux, Pascal Hols
Lactococcus lactis is one of the most commonly used lactic acid bacteria in the dairy industry. Activation of competence for natural DNA transformation in this species would greatly improve the selection of novel strains with desired genetic traits. Here, we investigated the activation of natural transformation in L. lactis ssp. cremoris KW2, a strain of plant origin whose genome encodes the master competence regulator ComX and the complete set of proteins usually required for natural transformation. In the absence of knowledge about competence regulation in this species, we constitutively overproduced ComX in a reporter strain of late competence phase activation and showed, by transcriptomic analyses, a ComX-dependent induction of all key competence genes...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625995/novel-antibiotic-resistance-determinants-from-agricultural-soil-exposed-to-antibiotics-widely-used-in-human-medicine-and-animal-farming
#9
Calvin Ho-Fung Lau, Kalene van Engelen, Stephen Gordon, Justin Renaud, Edward Topp
Antibiotic resistance has emerged globally as one of the biggest threats to human and animal health. Although the excessive use of antibiotics is recognized for accelerating the selection for resistance, there is a growing body of evidence suggesting that natural environments are "hotspots" for the development of both ancient and contemporary resistance mechanisms. Given that pharmaceuticals can be entrained onto agricultural land through anthropogenic activities, this could be a potential driver for the emergence and dissemination of resistance in soil bacteria...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625994/a-small-protein-hemp-is-a-transcriptional-activator-for-hemin-uptake-operon-in-burkholderia-multivorans-atcc-17616
#10
Takuya Sato, Shouta Nonoyama, Akane Kimura, Yuji Nagata, Yoshiyuki Ohtsubo, Masataka Tsuda
Iron and heme play very important roles in various metabolic functions in bacteria, and their intracellular homeostasis is maintained because high concentrations of free forms of these molecules greatly facilitate the Fenton reaction-mediated production of large amounts of reactive oxygen species that severely damage various biomolecules. Ferric uptake regulator (Fur) from Burkholderiamultivorans ATCC 17616 is an iron-responsive global transcriptional regulator, and its fur deletant exhibits pleiotropic phenotypes...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625993/survival-of-h5n1-highly-pathogenic-avian-influenza-virus-in-tissues-derived-from-experimentally-infected-chickens
#11
Yu Yamamoto, Kikuyasu Nakamura, Masaji Mase
Eurasian lineage H5N1 highly pathogenic avian influenza (HPAI) virus has been a severe threat to the poultry industry since its emergence in 1996. The carcass or tissues derived from infected birds may have the risk of the virus spreading to humans, animals, and the surrounding environment. In this study, we investigated the survival of the virus in feather, muscle, and liver tissues collected from six chickens (Gallus gallus) experimentally infected with H5N1 HPAI virus. The tissues were stored at +4°C or +20°C and viral isolation was performed at different times for 360 days...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625992/flow-cytometry-a-powerful-novel-tool-to-assess-viability-of-fungal-conidia-in-metal-working-fluids
#12
D Vanhauteghem, K Demeyere, N Callaert, A Boelaert, G Haesaert, K Audenaert, E Meyer
Fungal contamination of metal working fluids (MWF) is a dual problem in automatized processing plants because resulting fungal biofilms obstruct cutting, drilling and polishing machines. Moreover, some fungal species of MWF comprise pathogens such as Fusarium solani Therefore, the development of an accurate analytical tool to evaluate conidia viability in MWF is important. We developed a flow cytometric method to measure fungal viability in MWF using F. solani as model organism. To validate this method, viable and dead conidia were mixed in several proportions and flow cytometrically analyzed...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625991/different-amplicon-targets-for-sequencing-based-studies-of-fungal-diversity
#13
Francesca De Filippis, Manolo Laiola, Giuseppe Blaiotta, Danilo Ercolini
Target-gene amplicon sequencing is the most exploited high-throughput sequencing application in microbial ecology. The targets are taxonomically relevant genes with the 16S rRNA being the gold standard for bacteria. As for Fungi, the most commonly used target is the internal transcribed spacer (ITS). However, the uneven ITS length among species may promote preferential amplification and sequencing and incorrect estimation of their abundance. Therefore, the use of different targets is desirable. We evaluated the use of three different target amplicons for the characterization of fungal diversity...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625990/bioavailability-of-carbohydrate-content-in-natural-and-transgenic-switchgrasses-for-the-extreme-thermophile-caldicellulosiruptor-bescii
#14
Jeffrey V Zurawski, Piyum A Khatibi, Hannah O Akinosho, Christopher T Straub, Scott H Compton, Jonathan M Conway, Laura L Lee, Arthur J Ragauskas, Brian H Davison, Michael W W Adams, Robert M Kelly
Improving access to the carbohydrate content of lignocellulose is key to reducing recalcitrance for microbial deconstruction and conversion to fuels and chemicals. Caldicellulosiruptor bescii completely solubilizes naked microcrystalline cellulose, yet this transformation is impeded within the context of the plant cell wall by a network of lignin and hemicellulose. Here, the bioavailability of carbohydrates to C. bescii at 70°C was examined for reduced lignin transgenic switchgrass lines COMT3(+) and MYB Trans, their corresponding parental lines (cultivar Alamo) COMT3(-) and MYB WT, and natural variant cultivar Cave-in-Rock (CR)...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625989/rapid-high-throughput-identification-of-anthrax-causing-and-emetic-bacillus-cereus-group-genome-assemblies-using-btyper-a-computational-tool-for-virulence-based-classification-of-bacillus-cereus-group-isolates-using-nucleotide-sequencing-data
#15
Laura M Carroll, Jasna Kovac, Rachel A Miller, Martin Wiedmann
The Bacillus cereus group comprises nine species, several of which are pathogenic. Differentiating between isolates that may cause disease and those that do not is a matter of public health and economic importance, but can be particularly challenging due to the high genomic similarity of the group. To this end, we have developed BTyper, a computational tool that employs a combination of (i) virulence gene-based typing, (ii) multi-locus sequence typing (MLST), (iii) panC clade typing, and (iv) rpoB allelic typing to rapidly classify B...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625988/modification-of-a-pollen-trap-design-to-capture-airborne-conidia-of-entomophaga-maimaiga-and-detection-by-quantitative-pcr
#16
Tonya D Bittner, Ann E Hajek, Andrew M Liebhold, Harold Thistle
The goal of this study was to develop effective and practical field sampling methods for quantifying aerial deposition of airborne conidia of Entomophaga maimaiga over space and time. This important fungal pathogen is a major cause of larval mortality in invasive gypsy moth (Lymantria dispar) populations in the United States. Airborne conidia of this pathogen are relatively large (similar in size to pollen) with unusual characteristics, requiring specialized methods for collection and quantification. Initially, dry sampling (settling of spores from the air onto a dry surface) was used to confirm the detectability of E...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625987/metabolic-engineering-of-actinobacillus-succinogenes-provides-insights-into-succinic-acid-biosynthesis
#17
Michael T Guarnieri, Yat-Chen Chou, Davinia Salvachúa, Ali Mohagheghi, Peter C St John, Darren J Peterson, Yannick J Bomble, Gregg T Beckham
Actinobacillus succinogenes, a gram-negative, facultative anaerobe, exhibits the native capacity to convert pentose and hexose sugars to succinic acid (SA) with high yield as a tricarboxylic acid (TCA) cycle intermediate. In addition, A. succinogenes is capnophilic, incorporating CO2 into SA, making this organism an ideal candidate host for conversion of lignocellulosic sugars and CO2 to an emerging commodity bioproduct sourced from renewable feedstocks. In this work, we report the development of facile metabolic engineering capabilities in A...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625986/the-irr-and-rira-proteins-participate-in-a-complex-regulatory-circuit-and-act-in-concert-to-modulate-bacterioferritin-expression-in-ensifer-meliloti-1021
#18
Daniela Costa, Vanesa Amarelle, Claudio Valverde, Mark R O'Brian, Elena Fabiano
In this work we found that the bfr gene of the rhizobial species Ensifer meliloti, encoding a bacterioferritin iron storage protein, is involved in iron homeostasis and oxidative stress response. This gene is located downstream and overlapping the smc03787 ORF. No well predicted RirA or Irr boxes were found in the region immediately upstream the bfr gene although two presumptive RirA boxes and one presumptive Irr box were present in the putative promoter of smc03787 We demonstrate that bfr gene expression is enhanced under iron sufficient condition and that Irr and RirA modulate this expression...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625985/periplasmic-nicotine-dehydrogenase-ndhab-utilizes-pseudoazurin-as-its-physiological-electron-acceptor-in-agrobacterium-tumefaciens-s33
#19
Wenjun Yu, Rongshui Wang, Haiyan Huang, Huijun Xie, Shuning Wang
Agrobacterium tumefaciens S33 can grow with nicotine as the sole source of carbon, nitrogen, and energy via a novel hybrid of the pyridine pathway and the pyrollidine pathway. Characterization of the enzymes involved in the hybrid pathway is important for understanding its biochemical mechanism. Here we report that the molybdenum-containing nicotine dehydrogenase (NdhAB), which catalyzes the initial step of nicotine degradation, is located in the periplasm of strain S33, while the 6-hydroxynicotine oxidase and 6-hydroxypseudooxynicoine oxidase are in the cytoplasm...
June 16, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28625984/indole-induced-reversion-of-intrinsic-multi-antibiotic-resistance-in-lysobacter-enzymogenes
#20
Yong Han, Yan Wang, Yameng Yu, Haotong Chen, Yuemao Shen, Liangcheng Du
Lysobacter are a group of environmental bacteria that are emerging as a new source of antibiotics. One characteristic of Lysobacter is intrinsic resistance to multiple antibiotics, which had not been studied. To understand the resistant mechanism, we tested the effect of blocking two-component regulator systems (TCS) on antibiotic resistance of L. enzymogenes, a prolific producer of antibiotics. Upon treatment with LED209, an inhibitor of the widespread TCS QseC/QseB, L. enzymogenes produced a large amount of an unknown metabolite that was barely detectable in the untreated culture...
June 16, 2017: Applied and Environmental Microbiology
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