[Show abstract][Hide abstract] ABSTRACT: Pseudogulbenkiania ferrooxidans strain 2002 was isolated as a lithoautotrophic, Fe(II)-oxidizing, nitrate-reducing bacterium. Phylogenetically, it is in a clade within the family Neisseriaceae in the order Nessieriales of the class Betaproteobacteria. It is anticipated that comparative genomic analysis of this strain with other nitrate-dependent, Fe(II)-oxidizing bacteria will aid in the elucidation of the genetics and biochemistry underlying this critically important geochemical metabolism.
Journal of bacteriology 05/2012; 194(9):2400-1. DOI:10.1128/JB.00214-12 · 2.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Azospira suillum strain PS (formally Dechlorosoma suillum strain PS) is a metabolically versatile betaproteobacterium first identified for its ability to grow by dissimilatory reduction
of perchlorate and chlorate [denoted (per)chlorate]. Together with Dechloromonas species, these two genera represent the dominant (per)chlorate-reducing bacteria in mesophilic freshwater environments. In
addition to (per)chlorate reduction, A. suillum is capable of the anaerobic oxidation of humic substances and is the first anaerobic nitrate-dependent Fe(II) oxidizer outside
the Diaphorobacter and Acidovorax genera for which there is a completed genome sequence.
Journal of bacteriology 05/2012; 194(10):2767-8. DOI:10.1128/JB.00124-12 · 2.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Despite their importance in iron redox cycles and bioenergy production, the underlying physiological, genetic, and biochemical mechanisms of extracellular electron transfer by Gram-positive bacteria remain insufficiently understood. In this work, we investigated respiration by Thermincola potens strain JR, a Gram-positive isolate obtained from the anode surface of a microbial fuel cell, using insoluble electron acceptors. We found no evidence that soluble redox-active components were secreted into the surrounding medium on the basis of physiological experiments and cyclic voltammetry measurements. Confocal microscopy revealed highly stratified biofilms in which cells contacting the electrode surface were disproportionately viable relative to the rest of the biofilm. Furthermore, there was no correlation between biofilm thickness and power production, suggesting that cells in contact with the electrode were primarily responsible for current generation. These data, along with cryo-electron microscopy experiments, support contact-dependent electron transfer by T. potens strain JR from the cell membrane across the 37-nm cell envelope to the cell surface. Furthermore, we present physiological and genomic evidence that c-type cytochromes play a role in charge transfer across the Gram-positive bacterial cell envelope during metal reduction.
[Show abstract][Hide abstract] ABSTRACT: The levels of integron abundance and diversity in soil amended with pig slurry were studied. Real-time PCR illustrated a significant increase in class 1 integron prevalence after slurry application, with increased prevalence still evident at 10 months after application. Culture-dependent data revealed 10 genera, including putative human pathogens, carrying class 1 and 2 integrons.
[Show abstract][Hide abstract] ABSTRACT: Acidovorax ebreus strain TPSY is the first anaerobic nitrate-dependent Fe(II) oxidizer for which there is a completed genome sequence. Preliminary protein annotation revealed an organism optimized for survival in a complex environmental system. Here, we briefly report the completed and annotated genome sequence of strain TPSY.
Journal of bacteriology 12/2009; 192(5):1475-6. DOI:10.1128/JB.01449-09 · 2.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The prevalences of three sulfonamide resistance genes, sul1, sul2, and sul3 and sulfachloropyridazine (SCP) resistance were determined in bacteria isolated from manured agricultural clay soils and
slurry samples in the United Kingdom over a 2-year period. Slurry from tylosin-fed pigs amended with SCP and oxytetracycline
was used for manuring. Isolates positive for sul genes were further screened for the presence of class 1 and 2 integrons. Phenotypic resistance to SCP was significantly higher
in isolates from pig slurry and postapplication soil than in those from preapplication soil. Of 531 isolates, 23% carried
sul1, 18% sul2, and 9% sul3 only. Two percent of isolates contained all three sul genes. Class 1 and class 2 integrons were identified in 5% and 11.7%, respectively, of sul-positive isolates. In previous reports, sul1 was linked to class 1 integrons, but in this study only 8% of sul1-positive isolates carried the intI1 gene. Sulfonamide-resistant pathogens, including Shigella flexneri, Aerococcus spp., and Acinetobacter baumannii, were identified in slurry-amended soil and soil leachate, suggesting a potential environmental reservoir. Sulfonamide resistance
in Psychrobacter, Enterococcus, and Bacillus spp. is reported for the first time, and this study also provides the first description of the genotypes sul1, sul2, and sul3 outside the Enterobacteriaceae and in the soil environment.