Genomic investigations of acute munitions exposures on the health and skin microbiome composition of leopard frog (Rana pipiens) tadpoles.

Natural communities of microbes inhabiting amphibian skin, the skin microbiome, are critical to supporting amphibian health and disease resistance. To enable the pro-active health assessment and management of amphibians on Army installations and beyond, we investigated the effects of acute (96h) munitions exposures to Rana pipiens (leopard frog) tadpoles and the associated skin microbiome, integrated with RNAseq-based transcriptomic responses in the tadpole host. Tadpoles were exposed to the legacy munition 2,4,6-trinitrotoluene (TNT), the new insensitive munition (IM) formulation, IMX-101, and the IM constituents nitroguinidine (NQ) and 1-methyl-3-nitroguanidine (MeNQ).

Multiple stressors in multiple species: Effects of different RDX soil concentrations and differential water-resourcing on RDX fate, plant health, and plant survival.

Response to simultaneous stressors is an important facet of plant ecology and land management. In a greenhouse trial, we studied how eight plant species responded to single and combined effects of three soil concentrations of the phytotoxic munitions constituent RDX and two levels of water-resourcing. In an outdoor trial, we studied the effects of high RDX soil concentration and two levels of water-resourcing in three plant species.

Effects of chitin and temperature on sub-Arctic soil microbial and fungal communities and biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4-dinitrotoluene (DNT).

Climate warming in the Arctic and the thawing of frozen carbon stocks are leading to uncertainty as to how bacterial communities will respond, including pollutant degrading bacteria. This study investigated the effects of carbon stimulation and temperature on soil microbial community diversity and explosive biodegradation in two sub-Arctic soils. Chitin as a labile carbon source stimulated overall microbial activities as reflected by increases in basal respiration (three to tenfold) and potential nitrification activity (two to fourfold) compared to unamended soil.

Enhanced plasmid-mediated bioaugmentation of RDX-contaminated matrices in column studies using donor strain Gordonia sp. KTR9.

Horizontal gene transfer (HGT) is the lateral movement of genetic material between organisms. The RDX explosive-degrading bacterium Gordonia sp. KTR9 has been shown previously to transfer the pGKT2 plasmid containing the RDX degradative genes (xplAB) by HGT.

Rhizosphere Microbial Communities of and From Restored and Natural Tidal Marshes on Deer Island, Mississippi.

The U. S. Gulf of Mexico is experiencing a dramatic increase in tidal marsh restoration actions, which involves planting coastal areas with smooth cordgrass () and black needlerush () for erosion control and to provide habitat for fish and wildlife.

RDX degradation in bioaugmented model aquifer columns under aerobic and low oxygen conditions.

Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation.

Biodegradation of insensitive munition formulations IMX101 and IMX104 in surface soils.

The biodegradation potential of insensitive munition melt cast formulations IMX101 and IMX104 was investigated in two unamended training range soils under aerobic and anaerobic growth conditions. Changes in community profiles in soil microcosms were monitored via high-throughput 16S rRNA sequencing over the course of the experiments to infer key microbial phylotypes that may be linked to IMX degradation. Complete anaerobic biotransformation occurred for IMX101 and IMX104 constituents 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one during the 30-day incubation period with Camp Shelby (CS) soil.

Comparative Genomics and Metabolic Analysis Reveals Peculiar Characteristics of Rhodococcus opacus Strain M213 Particularly for Naphthalene Degradation.

The genome of Rhodococcus opacus strain M213, isolated from a fuel-oil contaminated soil, was sequenced and annotated which revealed a genome size of 9,194,165 bp encoding 8680 putative genes and a G+C content of 66.72%. Among the protein coding genes, 71.

Evaluation of Biostimulation and Bioaugmentation To Stimulate Hexahydro-1,3,5-trinitro-1,3,5,-triazine Degradation in an Aerobic Groundwater Aquifer.

Hexahydro-1,3,5-trinitro-1,3,5,-triazine (RDX) is a toxic and mobile groundwater contaminant common to military sites. This study compared in situ RDX degradation rates following bioaugmentation with Gordonia sp. strain KTR9 (henceforth KTR9) to rates under biostimulation conditions in an RDX-contaminated aquifer in Umatilla, OR.

Metagenomic analysis of denitrifying wastewater enrichment cultures able to transform the explosive, 3-nitro-1,2,4-triazol-5-one (NTO).

Removal of 3-nitro-1,2,4-triazol-5-one (NTO) was investigated in conjunction with heterotrophic and autotrophic denitrifying growth conditions by a microbial consortium from a wastewater treatment plant. Microcosms were supplemented with molasses, methanol, or thiosulfate. Cultures were passaged twice by transferring 10 % of the culture volume to fresh media on days 11 and 21.

Evaluation of microbial transport during aerobic bioaugmentation of an RDX-contaminated aquifer.

In situ bioaugmentation with aerobic hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading bacteria is being considered for treatment of explosives-contaminated groundwater at Umatilla Chemical Depot, Oregon (UMCD). Two forced-gradient bacterial transport tests of site groundwater containing chloride or bromide tracer and either a mixed culture of Gordonia sp. KTR9 (xplA (+)Km(R)), Rhodococcus jostii RHA1 (pGKT2 transconjugant; xplA (+)Km(R)) and Pseudomonas fluorescens I-C (xenB (+)), or a single culture of Gordonia sp.

Laboratory evaluation of bioaugmentation for aerobic treatment of RDX in groundwater.

The potential for bioaugmentation with aerobic explosive degrading bacteria to remediate hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contaminated aquifers was demonstrated. Repacked aquifer sediment columns were used to examine the transport and RDX degradation capacity of the known RDX degrading bacterial strains Gordonia sp. KTR9 (modified with a kanamycin resistance gene) Pseudomonas fluorescens I-C, and a kanamycin resistant transconjugate Rhodococcus jostii RHA1 pGKT2:Km+.

Dissemination of bacterial fluoroquinolone resistance in two multidrug-resistant enterobacteriaceae.

Bacterial resistance to antimicrobials has become one of the greatest challenges for clinical microbiologists and healthcare practitioners worldwide. Acquisition of resistance genes has proven to be difficult to characterize and is largely uncontrollable in the environment. Here we sought to characterize conjugal horizontal gene transfer of plasmid-encoded fluoroquinolone resistance genes from two strains of Enterobacteriaceae, one clinical and one from a municipal wastewater treatment plant environment.

Biotransformation of explosives by Reticulitermes flavipes--associated termite Endosymbionts.

Background/aims: Termites have an important role in the carbon and nitrogen cycles despite their reputation as destructive pests. With the assistance of microbial endosymbionts, termites are responsible for the conversion of complex biopolymers into simple carbon substrates. Termites also rely on endosymbionts for fixing and recycling nitrogen.

Draft Genome Sequence of the Multidrug-Resistant Escherichia coli Strain LR09, Isolated from a Wastewater Treatment Plant.

We report the draft genome sequence of Escherichia coli O1:H6 strain LR09, which was isolated from a wastewater treatment plant and displays high resistance to five fluoroquinolone antimicrobials. The assembled data determine that the strain clusters with E. coli phylogroup F and harbors a plasmid conferring resistance to a broad spectrum of antibiotics.

Role of nitrogen limitation in transformation of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) by Gordonia sp. strain KTR9.

The transcriptome of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine)-degrading strain Gordonia sp. strain KTR9 and its glnR mutant were studied as a function of nitrogen availability to further investigate the observed ammonium-mediated inhibition of RDX degradation. The results indicate that nitrogen availability is a major determinant of RDX degradation and xplA gene expression in KTR9.

Functional characterization of pGKT2, a 182-kilobase plasmid containing the xplAB genes, which are involved in the degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine by Gordonia sp. strain KTR9.

Several microorganisms have been isolated that can transform hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a cyclic nitramine explosive. To better characterize the microbial genes that facilitate this transformation, we sequenced and annotated a 182-kb plasmid, pGKT2, from the RDX-degrading strain Gordonia sp. KTR9.

Single nucleotide polymorphism analysis of the major tripartite multidrug efflux pump of Escherichia coli: functional conservation in disparate animal reservoirs despite exposure to antimicrobial chemotherapy.

AcrAB-TolC imparts a strong intrinsic resistance phenotype to many clinically significant molecules in Escherichia coli. This complex is composed of a pump, AcrB, and a periplasmic protein, AcrA, that exports substrates through a common outer membrane porin, TolC. A sequence survey of the pump-specific components, acrA and acrB, was conducted on three discrete animal reservoirs: rodents, bovines, and catfish.

Interaction of dietary resveratrol with animal-associated bacteria.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), an antifungal phytoalexin produced by grapes, peanuts, and Japanese knotweeds, is thought to be a beneficial dietary phytochemical in red wine and grape juice. Information on its antibacterial properties and biotransformation, however, is limited. We surveyed the interactions of resveratrol with 43 strains of bacterial species that are often animal- or human-associated.

Transformation of N-phenylpiperazine by mixed cultures from a municipal wastewater treatment plant.

Samples from a wastewater treatment plant were used as inocula for mixed cultures dosed with N-phenylpiperazine (NPP), a model compound containing the piperazine ring found in many fluoroquinolones. Chemical analyses showed that NPP (50 mg liter(-1)) disappeared in 12 days, with the appearance of a transient metabolite and two nitrosated compounds.

The recent evolution of pentachlorophenol (PCP)-4-monooxygenase (PcpB) and associated pathways for bacterial degradation of PCP.

Man-made polychlorinated phenols such as pentachlorophenol (PCP) have been used extensively since the 1920s as preservatives to prevent fungal attack on wood. During this time, they have become serious environmental contaminants. Despite the recent introduction of PCP in the environment on an evolutionary time scale, PCP-degrading bacteria are present in soils worldwide.

Detection and decontamination of residual energetics from ordnance and explosives scrap.

Extensive manufacturing of explosives in the last century has resulted in widespread contamination of soils and waters. Decommissioning and cleanup of these materials has also led to concerns about the explosive hazards associated with residual energetics still present on the surfaces of ordnance and explosives scrap. Typically, open burning or detonation is used to decontaminate ordinance and explosive scrap.

Characterization of JP-7 jet fuel degradation by the bacterium Nocardioides luteus strain BAFB.

In the fall of 1996, numerous bacteria capable of degrading JP-7 jet fuel were isolated from soil collected at Beale Air Force Base in northern California. The most prevalent organism, identified as Nocardioides luteus by16s rRNA sequencing (MIDI Labs, Inc.), was selected for further analysis.