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Applied and Environmental Microbiology

Mukesh Jain, Alejandra Munoz-Bodnar, Dean W Gabriel
Methylglyoxal (MG) is a cytotoxic, non-enzymatic byproduct of glycolysis that readily glycates proteins and DNA, resulting in carbonyl stress. Glyoxalase I and II (GloA and GloB) sequentially convert MG into D-lactic acid using glutathione (GSH) as a cofactor. The glyoxalase system is essential for the mitigation of MG-induced carbonyl stress, preventing subsequent cell death, and recycling GSH for maintenance of cellular redox poise. All pathogenic Liberibacters identified to date are uncultured, including "Candidatus Liberibacter asiaticus", a psyllid endosymbiont and causal agent of the severely damaging citrus disease 'huanglongbing'...
September 22, 2017: Applied and Environmental Microbiology
H Nothaft, M E Perez-Muñoz, G J Gouveia, R M Duar, J J Wanford, L Lango-Scholey, C G Panagos, V Srithayakumar, G S Plastow, C Coros, C D Bayliss, A S Edison, J Walter, C M Szymanski
Source attribution studies report that consumption of contaminated poultry is the primary source for acquiring human campylobacteriosis. Oral administration of an engineered Escherichia coli strain expressing the Campylobacter jejuni N-glycan reduces bacterial colonization in specific-pathogen-free leghorn chickens, but only a fraction of birds respond to vaccination. Optimizing the vaccine for commercial broiler chickens has great potential to prevent pathogen entry into the food chain. Here, we tested the same vaccination approach in broilers and observed similar efficacy in pathogen load reduction, stimulation of host IgY response, lack of C...
September 22, 2017: Applied and Environmental Microbiology
Arthur Guljamow, Marco Kreische, Keishi Ishida, Anton Liaimer, Bjørn Altermark, Lars Bähr, Christian Hertweck, Rudolf Ehwald, Elke Dittmann
Terrestrial symbiotic cyanobacteria of the genus Nostoc exhibit a large potential for the production of bioactive natural products of the nonribosomal peptide, polyketide and ribosomal peptide classes, yet most of the biosynthetic gene clusters are silent under conventional cultivation conditions. In the present study, we have utilized a high-density cultivation approach recently developed for phototrophic bacteria to rapidly generate biomass of the filamentous bacteria up to a density of 400 g wet weight/L...
September 22, 2017: Applied and Environmental Microbiology
Nan Li, Yongtao Zhu, Benjamin R LaFrentz, Jason P Evenhuis, David W Hunnicutt, Rachel A Conrad, Paul Barbier, Connor W Gullstrand, Jack E Roets, Jonathan L Powers, Surashree S Kulkarni, Devon H Erbes, Julio C García, Pin Nie, Mark J McBride
Flavobacterium columnare, a member of the phylum Bacteroidetes, causes columnaris disease in wild and aquaculture-reared freshwater fish. The mechanisms responsible for columnaris disease are not known. Many members of the phylum Bacteroidetes use type IX secretion systems (T9SSs) to secrete enzymes, adhesins, and proteins involved in gliding motility. The F. columnare genome has all of the genes needed to encode a T9SS. gldN, which encodes a core component of the T9SS, was deleted in wild type strains of F...
September 22, 2017: Applied and Environmental Microbiology
J H Shahbazian, P D Hahn, S Ludwig, J Ferguson, P Baron, A Christ, K Spicer, P Tolomeo, A M Torrie, W B Bilker, V C Cluzet, B Hu, K Julian, I Nachamkin, S C Rankin, D O Morris, E Lautenbach, M F Davis
Patients with community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) infections contribute to MRSA contamination of the home environment, and may be re-exposed to MRSA strains from this reservoir. This study evaluates One Health risk factors that focus on the relationship between humans, animals and the environment for increased prevalence of multiple antimicrobial resistant MRSA in the home environment. During a trial of patients with CO-MRSA infection, MRSA was isolated from the household environment at baseline and three months later, following randomization of patients and household members to mupirocin-based decolonization therapy or education control...
September 22, 2017: Applied and Environmental Microbiology
Mianmian Chen, Lei Zhang, Sheikheldin A Abdelgader, Li Yu, Juntian Xu, Huochun Yao, Chengping Lu, Wei Zhang
The use of phages as antibacterial agents is limited by their generally narrow host range. The aim of this study was to make a T4-like phage, WG01, obtain the host range of another T4-like phage, QL01, by replacing its host determinant gene region with that of QL01. This process triggered a direct expansion of the WG01 host range. The offspring of WG01 obtained the host ranges of both QL01 and WG01, as well as the ability to infect eight additional host bacteria in comparison to the wildtype strains. WQD had the widest host range; therefore, the corresponding QD fragments could be used for constructing a homologous sequence library...
September 22, 2017: Applied and Environmental Microbiology
Vincent G Martinson, Javier Carpinteyro-Ponce, Nancy A Moran, Therese A Markow
Almost all animals possess microbial gut communities, but the nature of these communities varies immensely. For example, in social bees and mammals, composition is relatively constant within species and dominated by specialist bacteria that do not live elsewhere; whereas, in laboratory studies and field surveys of Drosophila melanogaster, gut communities consist of bacteria that are ingested with food and that vary widely among individuals and localities. We addressed whether an ecological specialist in its natural habitat has a microbiota dominated by gut specialists or by environmental bacteria...
September 22, 2017: Applied and Environmental Microbiology
Carlos A Loncoman, Carol A Hartley, Mauricio J C Coppo, Paola K Vaz, Andrés Diaz-Méndez, Glenn F Browning, Maricarmen García, Stephen Spatz, Joanne M Devlin
Recombination is a feature of many alphaherpesviruses that infect people and animals. Infectious laryngotracheitis virus (ILTV - Gallid alphaherpesvirus 1), causes respiratory disease in chickens, resulting in significant production losses in poultry industries worldwide. Natural (field) ILTV recombination is widespread, particularly recombination between attenuated ILTV vaccine strains to create virulent viruses. These virulent recombinants have had a major impact on animal health. Recently, the development of a single nucleotide polymorphism (SNP) genotyping assay for ILTV has helped to understand ILTV recombination under laboratory settings...
September 22, 2017: Applied and Environmental Microbiology
Cui-Wei Chu, Bin Liu, Na Li, Shi-Gang Yao, Dan Cheng, Jia-Dong Zhao, Ji-Guo Qiu, Xin Yan, Qin He, Jian He
Thiobencarb is a thiocarbamate herbicide used in rice paddies worldwide. Microbial degradation plays a crucial role in the dissipation of thiobencarb in the environment. However, the physiological and genetic mechanisms underlying thiobencarb degradation remain unknown. In this study, a novel thiobencarb degradation pathway was proposed in Acidovorax sp. T1. Thiobencarb was oxidized and cleaved at the C-S bond, generating diethylcarbamothioic S-acid and 4-chlorobenzaldehyde (4CDA). 4CDA was then oxidized to 4-chlorobenzoic acid (4CBA) and hydrolytically dechlorinated to 4-hydroxybenzoic acid (4HBA)...
September 22, 2017: Applied and Environmental Microbiology
Nicole Wiesemann, Lucy Bütof, Martin Herzberg, Gerd Hause, Lutz Berthold, Barbara Etschmann, Joël Brugger, Gema Martinez-Criado, Dirk Dobritzsch, Sacha Baginsky, Frank Reith, Dietrich H Nies
The bacterium Cupriavidus metallidurans is capable of reducing toxic gold(I/III)-complexes and biomineralizing them into metallic gold (Au) nanoparticles, thereby mediating the (trans)formation of Au nuggets. In Au-rich soils, most transition metals do not interfere with the resistance of this bacterium to toxic mobile Au-complexes and can be removed from the cell by plasmid-encoded metal efflux systems. Copper is a noticeable exception: the presence of Au-complexes and Cu-ions results in synergistic toxicity, which is accompanied by an increased cytoplasmic Cu content and formation of Au nanoparticles in the periplasm...
September 22, 2017: Applied and Environmental Microbiology
Hugo Oliveira, Graça Pinto, Hanne Hendrix, Jean-Paul Noben, Jan Gawor, Andrew M Kropinski, Małgorzata Łobocka, Rob Lavigne, Joana Azeredo
Providencia rettgeri is emerging as a new opportunistic pathogen with high antibiotic resistance. The need to find alternative methods to control antibiotic resistant bacteria and the recent advances in phage therapy motivates the search of new phages able to infect Providencia spp.. This study describes the isolation and characterization of an obligatory lytic phage vB_PreS_PR1 (PR1) with therapeutic potential against drug-resistant P. rettgeri PR1 is a siphovirus. Its virion DNA size (118,537 bp), transcriptional organization, terminal repeats (10,461 bp) and nicks in the 3' -5' strand are similar to those of phage T5...
September 22, 2017: Applied and Environmental Microbiology
David H Kingsley, Johnna P Fay, Kevin Calci, Régis Pouillot, Jacquelina Woods, Haiqiang Chen, Brendan A Niemira, Jane M Van Doren
This study examined the inactivation of human norovirus (HuNoV) GI.1 and GII.4 by chlorine under conditions that mimic sewage treatment. Using a porcine gastric mucin-magnetic bead (PGM-MB) assay, no statistically significant loss in HuNoV binding (inactivation) was observed for secondary effluent treatments of ≤25 ppm total chlorine, while for both strains 50 and 100 ppm treatments resulted in ≤0.8 log10 and ≥3.9 log10 reductions, respectively. Treatments of 10, 25, 50, and 100 ppm chlorine inactivated 0...
September 22, 2017: Applied and Environmental Microbiology
Lara M Jochum, Xihan Chen, Mark A Lever, Alexander Loy, Bo Barker Jørgensen, Andreas Schramm, Kasper U Kjeldsen
Most sulfate-reducing microorganisms (SRM) present in subsurface marine sediments belong to uncultured groups only distantly related to known SRM and it remains unclear how changing geochemical zones and sediment depth influence their community structure. We mapped the community composition and abundance of SRM by amplicon-sequencing and quantifying dsrB, which encodes dissimilatory sulfite reductase subunit beta, in sediment samples covering different vertical geochemical zones ranging from the surface sediment to the deep sulfate-depleted subsurface at four locations in Aarhus Bay, Denmark...
September 22, 2017: Applied and Environmental Microbiology
Yuanyuan Cheng, Dandan Wang, Jingyan Gu, Junge Li, Huihui Liu, Fuchuan Li, Wenjun Han
Bifunctional alginate lyases can efficiently degrade alginate comprised of mannuronate (M) and guluronate (G), but their substrate-degrading modes have not been thoroughly elucidated to date. In this study, we present Aly1 as a novel bifunctional endolytic alginate lyase of the genus Flammeovirga The recombinant enzyme showed optimal activity at 50°C and pH 6.0. The enzyme produced unsaturated disaccharide (UDP2) and trisaccharide fractions as the final main alginate digests. Primary substrate-preference tests and further structure identification of various size-defined final oligosaccharide products demonstrated that Aly1 is a bifunctional alginate lyase and prefers G to M...
September 22, 2017: Applied and Environmental Microbiology
Rui Gao, Honglei Liu, Luying Xun
Heterotrophic bacteria have recently been reported to oxidize sulfide by using sulfide:quinone oxidoreductase (SQR) and persulfide dioxygenase (PDO) to sulfite and thiosulfate. In chemolithotrophic bacteria, both SQR and PDO have been reported to function in the periplasmic space with SQR as a peripheral membrane protein whose C-terminus inserts into the cytoplasmic membrane and PDO as a soluble protein. Cupriavidus pinatubonensis JMP134, best known for its ability to degrade 2,4-dichlorophenoxyacetic acid and other aromatic pollutants, has a gene cluster of sqr and pdo encoding CpSQR and CpPDO2...
September 22, 2017: Applied and Environmental Microbiology
Michael J Mitsch, George C diCenzo, Alison Cowie, Turlough M Finan
Symbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using a genetic and systems-level analyses. Expression of a malate specific transporter (MaeP) in Sinorhizobium meliloti Rm1021 dct mutants unable to transport C4-dicarboxylates resulted in malate import rates up to 30% that of wild type...
September 15, 2017: Applied and Environmental Microbiology
Ana Vieira, Amritha Ramesh, Alan M Seddon, Andrey V Karlyshev
Campylobacter jejuni is a foodborne pathogen recognized as the leading cause of human bacterial gastroenteritis. The wide use of antibiotics in medicine and in animal husbandry has led to an increased incidence of antibiotic resistance in Campylobacter In addition to a role in multidrug resistance, the Campylobacter CmeABC RND-type efflux pump, which is associated with multidrug resistance (MDR), may also be involved in virulence. As a vehicle of pathogenic microorganisms, the protozoan Acanthamoeba is a good model for the investigation of bacterial survival in the environment and molecular mechanisms of pathogenicity...
September 15, 2017: Applied and Environmental Microbiology
Doris Tisch, Kyle R Pomraning, James R Collett, Michael Freitag, Scott E Baker, Chia-Ling Chen, Paul Wei-Che Hsu, Yu Chien Chuang, Andre Schuster, Christoph Dattenböck, Eva Stappler, Michael Sulyok, Stefan Böhmdorfer, Josua Oberlerchner, Ting-Fang Wang, Monika Schmoll
The filamentous fungus Trichoderma reesei is predominantly found in the tropics, but also in more temperate regions, such as Europe and is widely known as producer of high amounts of plant cell wall degrading enzymes. We sequenced the genome of the sexually competent isolate CBS999.97, which is phenotypically different from female sterile QM6a, but can cross sexually with QM6a. Transcriptome data for growth on cellulose showed that entire CAZyme families are consistently differentially regulated between these strains...
September 15, 2017: Applied and Environmental Microbiology
Pongdet Piromyou, Teerana Greetatorn, Kamonluck Teamtisong, Panlada Tittabutr, Nantakorn Boonkerd, Neung Teaumroong
Bradyrhizobium encompasses a variety of bacteria that can live in symbiotic and endophytic associations with leguminous and non-leguminous plants such as rice. Therefore, it can be expected that rice endophytic bradyrhizobia can be applied in the rice-legume crop rotation system. Some endophytic bradyrhizobial strains were isolated from rice (Oryza sativa L.) tissues. The rice biomass could be enhanced when supplying KNO3, NH4NO3, or urea with bradyrhizobial strain inoculation, especially strain SUTN9-2. In contrast, the strains which suppressed rice growth were photosynthetic bradyrhizobia and also found to produce nitric oxide (NO) in the rice root...
September 15, 2017: Applied and Environmental Microbiology
Brett L Mellbye, Eva Spieck, Peter J Bottomley, Luis A Sayavedra-Soto
The genomes of many bacteria that participate in nitrogen cycling through the process of nitrification contain putative genes associated with acyl-homoserine lactone (AHL) quorum sensing (QS). AHL QS or bacterial cell-cell signaling is a method of bacterial communication and gene regulation and may be involved in nitrogen oxide fluxes or other important phenotypes in nitrifying bacteria. Here, we carried out a broad survey of AHL production in nitrifying bacteria in three steps. First, we analyzed the evolutionary history of AHL synthase and AHL receptor homologs in sequenced genomes and metagenomes of nitrifying bacteria to identify AHL synthase homologs in ammonia-oxidizing bacteria (AOB) of the genera Nitrosospira and nitrite-oxidizing bacteria (NOB) of the genera Nitrococcus, Nitrobacter, and Nitrospira Next, we screened cultures of both AOB and NOB cultures with uncharacterized AHL synthase genes and AHL synthase-negative nitrifiers by bioassay...
September 8, 2017: Applied and Environmental Microbiology
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