Effects of diesel and interactions with copper and other metals in an estuarine sediment microbial community.

Estuarine sediment microcosms were treated with combinations of diesel, copper (at two levels), and a mixture of heavy metals (mercury, cadmium, lead, and chromium; at two levels) mimicking the contaminant loadings found in harbor sediments. The effects on the microbial community were monitored by polar lipid fatty acid analysis. Diesel addition increased microbial biomass, caused shifts in some fatty acid structural groups, and decreased starvation biomarkers.

Treatment of nitric acid-, U(VI)-, and Tc(VII)-contaminated groundwater in intermediate-scale physical models of an in situ biobarrier.

Metal and hydrogen ion acidity and extreme nitrate concentrations at Department of Energy legacywaste sites pose challenges for successful in situ U and Tc bioimmobilization. In this study, we investigated a potential in situ biobarrier configuration designed to neutralize pH and remove nitrate and radionuclides from nitric acid-, U-, and Tc-contaminated groundwater for over 21 months. Ethanol additions to groundwater flowing through native sediment and crushed limestone effectively increased pH (from 4.

Physiological and taxonomic description of the novel autotrophic, metal oxidizing bacterium, Pseudogulbenkiania sp. strain 2002.

A lithoautotrophic, Fe(II) oxidizing, nitrate-reducing bacterium, strain 2002 (ATCC BAA-1479; =DSM 18807), was isolated as part of a study on nitrate-dependent Fe(II) oxidation in freshwater lake sediments. Here we provide an in-depth phenotypic and phylogenetic description of the isolate. Strain 2002 is a gram-negative, non-spore forming, motile, rod-shaped bacterium which tested positive for oxidase, catalase, and urease.

Multiply methyl-branched fatty acids and diacids in the polar lipids of a microaerophilic subsurface microbial community.

A previously unreported series of di- and tri-methylated fatty acids, as well as saturated and monounsaturated diacids were identified in polar lipids isolated from environmental subsurface sediment samples. Mechanisms are proposed for their formation, but their origin and role in cell membranes remains unknown.

Radiofrequency ablation for primary lung cancer and pulmonary metastases.

Lung cancer remains one of the leading causes of death throughout the world. Although surgery is the gold standard treatment for lung cancer, the majority of patients are not resectable at the time of diagnosis. Even among patients who are potentially resectable, many are treated nonoperatively because of inadequate pulmonary reserve or advanced comorbidities.

Prevalence of lysogeny among soil bacteria and presence of 16S rRNA and trzN genes in viral-community DNA.

Bacteriophages are very abundant in the biosphere, and viral infection is believed to affect the activity and genetic diversity of bacterial communities in aquatic environments. Lysogenic conversion, for example, can improve host fitness and lead to phage-mediated horizontal gene transfer. However, little is known about lysogeny and transduction in the soil environment.

Changes in microbial community composition and geochemistry during uranium and technetium bioimmobilization.

In a previous column study, we investigated the long-term impact of ethanol additions on U and Tc mobility in groundwater (M. M. Michalsen et al.

Identification and isolation of a Castellaniella species important during biostimulation of an acidic nitrate- and uranium-contaminated aquifer.

Immobilization of uranium in groundwater can be achieved through microbial reduction of U(VI) to U(IV) upon electron donor addition. Microbial community structure was analyzed in ethanol-biostimulated and control sediments from a high-nitrate (>130 mM), low-pH, uranium-contaminated site in Oak Ridge, TN. Analysis of small subunit (SSU) rRNA gene clone libraries and polar lipid fatty acids from sediments revealed that biostimulation resulted in a general decrease in bacterial diversity.

Uranium removal from groundwater via in situ biostimulation: Field-scale modeling of transport and biological processes.

During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community.

Analysis of diurnal and vertical microbial diversity of a hypersaline microbial mat.

Microbial mats are prokaryotic communities that provide model systems to analyze microbial diversity and ecophysiological interactions. Community diversity of microbial mat samples was assessed at 8:00 a.m.

Monitoring diel variations of physiological status and bacterial diversity in an estuarine microbial mat: an integrated biomarker analysis.

Microbial mats are highly productive microbial systems and a source of not-yet characterized microorganisms and metabolic strategies. In this article, we introduced a lipid biomarker/microbial isolation approach to detect short-term variations of microbial diversity, physiological and redox status, and also characterize lipid biomarkers from specific microbial groups that can be further monitored. Phospholipid fractions (PLFA) were examined for plasmalogens, indicative of certain anaerobes.

Lysophosphatidylethanolamine is a substrate for the short-chain alcohol dehydrogenase SocA from Myxococcus xanthus.

Short-chain alcohol dehydrogenases (SCADHs) synthesize a variety of intercellular signals and other chemically diverse products. It is difficult to predict the substrate of a SCADH on the basis of amino acid sequence homology, as the substrates are not known for most SCADHs. In Myxococcus xanthus, the SCADH CsgA is responsible for C signaling during fruiting body development, although the mechanism is unclear.

Novel lipids in Myxococcus xanthus and their role in chemotaxis.

Organisms that colonize solid surfaces, like Myxococcus xanthus, use novel signalling systems to organize multicellular behaviour. Phosphatidylethanolamine (PE) containing the fatty acid 16:1omega5 (Delta11) elicits a chemotactic response. The phenomenon was examined by observing the effects of PE species with varying fatty acid pairings.

Influence of agricultural antibiotics and 17beta-estradiol on the microbial community of soil.

Agricultural pharmaceuticals are a major environmental concern because of their hazardous effects on human and wildlife. This study analyzed phospholipid ester-linked fatty acids (PLFAs) and quinones to investigate the effects of a steroid (17beta-estradiol) and agricultural antibiotics (chlortetracycline and tylosin) on soil microbes in the laboratory. Two different types of soil were used: Sequatchie loam (0.

Application of nonlinear analysis methods for identifying relationships between microbial community structure and groundwater geochemistry.

The relationship between groundwater geochemistry and microbial community structure can be complex and difficult to assess. We applied nonlinear and generalized linear data analysis methods to relate microbial biomarkers (phospholipids fatty acids, PLFA) to groundwater geochemical characteristics at the Shiprock uranium mill tailings disposal site that is primarily contaminated by uranium, sulfate, and nitrate. First, predictive models were constructed using feedforward artificial neural networks (NN) to predict PLFA classes from geochemistry.

Microbial incorporation of 13C-labeled acetate at the field scale: detection of microbes responsible for reduction of U(VI).

A field-scale acetate amendment experiment was performed in a contaminated aquifer at Old Rifle, CO to stimulate in situ microbial reduction of U(VI) in groundwater. To evaluate the microorganisms responsible for microbial uranium reduction during the experiment, 13C-labeled acetate was introduced into well bores via bio-traps containing porous activated carbon beads (Bio-Sep). Incorporation of the 13C from labeled acetate into cellular DNA and phospholipid fatty acid (PLFA) biomarkers was analyzed in parallel with geochemical parameters.

Phospholipid furan fatty acids and ubiquinone-8: lipid biomarkers that may protect dehalococcoides strains from free radicals.

Dehalococcoides species have a highly restricted lifestyle and are only known to derive energy from reductive dehalogenation reactions. The lipid fraction of two Dehalococcoides isolates, strains BAV1 and FL2, and a tetrachloroethene-to-ethene-dechlorinating Dehalococcoides-containing consortium were analyzed for neutral lipids and phospholipid fatty acids. Unusual phospholipid modifications, including the replacement of unsaturated fatty acids with furan fatty acids, were detected in both Dehalococcoides isolates and the mixed culture.

Microbiological and geochemical heterogeneity in an in situ uranium bioremediation field site.

The geochemistry and microbiology of a uranium-contaminated subsurface environment that had undergone two seasons of acetate addition to stimulate microbial U(VI) reduction was examined. There were distinct horizontal and vertical geochemical gradients that could be attributed in large part to the manner in which acetate was distributed in the aquifer, with more reduction of Fe(III) and sulfate occurring at greater depths and closer to the point of acetate injection. Clone libraries of 16S rRNA genes derived from sediments and groundwater indicated an enrichment of sulfate-reducing bacteria in the order Desulfobacterales in sediment and groundwater samples.

Diversity of the microeukaryotic community in sulfide-rich Zodletone Spring (Oklahoma).

The microeukaryotic community in Zodletone Spring, a predominantly anaerobic sulfide and sulfur-rich spring, was examined using an 18S rRNA gene cloning and sequencing approach. The majority of the 288 clones sequenced from three different locations at Zodletone Spring belonged to the Stramenopiles, Alveolata, and Fungi, with members of the phylum Cercozoa, order Diplomonadida, and family Jakobidae representing a minor fraction of the clone library. No sequences suggesting the presence of novel kingdom level diversity were detected in any of the three libraries.

Effect of agricultural antibiotics on the persistence and transformation of 17beta-estradiol in a Sequatchie loam.

A laboratory incubation study was conducted to investigate the effect of agricultural antibiotics (sulfamethazine, tylosin, and chlortetracycline) on the persistence and transformation of 17beta-estradiol in Sequatchie loam. We measured concentrations of 17beta-estradiol and its primary metabolite (estrone) in soils spiked with antibiotics and 17beta-estradiol. Dehydrogenase activity (DHA) was also measured as an indicator of the total microbial activity of the soils.

Comparison of three extraction methods for 17beta-estradiol in sand, bentonite, and organic-rich silt loam.

Extraction is an important procedure for samples that contain soil because other compounds in soil may affect analysis of estrogens. This study was conducted to evaluate three different extraction methods for 17beta-estradiol in soil. Sand, bentonite, and organic-rich silt loam were spiked with 1 mg kg(-1) of 17beta-estradiol as a model compound of estrogens.

Feasibility of assessment of regulatory lipids in breath condensate as potential presymptomatic harbingers of pulmonary pathobiology.

Regulatory lipids from the airway surface readily form aerosols that can be recovered non-invasively by cooling expired breath to form breath condensate (BC). Regulatory lipids have been detected previously utilizing enzyme-linked-immunosorbent serologic assay (ELISA). Here we test the feasibility of assessment of regulatory lipids in BC by mass spectrometry so presently unknown lipid regulatory components can be detected without addition of specific antibodies as in the ELISA procedure.

Combined phospholipid biomarker-16S rRNA gene denaturing gradient gel electrophoresis analysis of bacterial diversity and physiological status in an intertidal microbial mat.

A combined lipid biomarker-16S rRNA gene denaturing gradient gel electrophoresis analysis was used to monitor changes in the physiological status, biomass, and microbial composition of a microbial mat. In the morning hours, an increase in the biomass of layers containing a high density of phototrophs and a decrease in the growth rate in the deep layers were observed. The combined approach also revealed differences in major groups of microorganisms, including green nonsulfur, gram-positive, and heterotrophic bacteria.

Synthesis and anticonvulsant evaluation of some new 2-substituted-3-arylpyrido[2,3-d]pyrimidinones.

A series of 2-substituted-3-arylpyrido[2,3-d]pyrimidinones was prepared for evaluation as potential anticonvulsants. In murine screening, compounds 4a-c having a 2-oxo-2-(4-pyridyl)ethyl group in the 2-position and a 2-substituted phenyl moiety at the 3-position of the pyridopyrimidinone system displayed the most potent anti-seizure activity in both the maximal electroshock (MES) and pentylenetetrazol (scPTZ) tests at doses in the 3-10mg/kg range. Compound 4c showed no agonist activity at the GABA(A) receptor and was unable to block presynaptic sodium and calcium channels in vitro.

Atmospheric pressure chemical ionization and atmospheric pressure photoionization for simultaneous mass spectrometric analysis of microbial respiratory ubiquinones and menaquinones.

An atmospheric pressure photoionization (APPI) source and an atmospheric pressure chemical ionization (APCI) source were compared for the selective detection of microbial respiratory ubiquinone and menaquinone isoprenologues using tandem mass spectrometry. Ionization source- and compound mass-dependent parameters were optimized individually for both sources, using the available quinone standards. Detection levels for the two ion sources were determined with ubiquinone-6 (UQ6) and menaquinone-4 (MK4, vitamin K2) standards using flow injection analysis and selected reaction monitoring (SRM).