Geobacter lovleyi sp. nov. strain SZ, a novel metal-reducing and tetrachloroethene-dechlorinating bacterium

A bacterial isolate, designated strain SZ, was obtained from noncontaminated creek sediment microcosms based on its ability to derive energy from acetate oxidation coupled to tetrachloroethene (PCE)-to-cis-1,2-dichloroethene (cis-DCE) dechlorination (i.e., chlororespiration). Hydrogen and pyruvate served as alternate electron donors for strain SZ, and the range of electron acceptors included (reduced products are given in brackets) PCE and trichloroethene [cis-DCE], nitrate [ammonium], fumarate [succinate], Fe(III) [Fe(II)], malate [succinate], Mn(IV) [Mn(II)], U(VI) [U(IV)], and elemental sulfur [sulfide]. PCE and soluble Fe(III) (as ferric citrate) were reduced at rates of 56.5 and 164 nmol min(-1) mg of protein(-1), respectively, with acetate as the electron donor. Alternate electron acceptors, such as U(VI) and nitrate, did not inhibit PCE dechlorination and were consumed concomitantly. With PCE, Fe(III) (as ferric citrate), and nitrate as electron acceptors, H(2) was consumed to threshold concentrations of 0.08 +/- 0.03 nM, 0.16 +/- 0.07 nM, and 0.5 +/- 0.06 nM, respectively, and acetate was consumed to 3.0 +/- 2.1 nM, 1.2 +/- 0.5 nM, and 3.6 +/- 0.25 nM, respectively. Apparently, electron acceptor-specific acetate consumption threshold concentrations exist, suggesting that similar to the hydrogen threshold model, the measurement of acetate threshold concentrations offers an additional diagnostic tool to delineate terminal electron-accepting processes in anaerobic subsurface environments. Genetic and phenotypic analyses classify strain SZ as the type strain of the new species, Geobacter lovleyi sp. nov., with Geobacter (formerly Trichlorobacter) thiogenes as the closest relative. Furthermore, the analysis of 16S rRNA gene sequences recovered from PCE-dechlorinating consortia and chloroethene-contaminated subsurface environments suggests that Geobacter lovleyi belongs to a distinct, dechlorinating clade within the metal-reducing Geobacter group. Substrate versatility, consumption of electron donors to low threshold concentrations, and simultaneous reduction of electron acceptors suggest that strain SZ-type organisms have desirable characteristics for bioremediation applications.     

A new Bacillus pasteurii urease inhibitor from Euphorbia decipiens

Inhibition of Bacillus pasteurii urease enzyme by 3,7,15-tri-O-acetyl-5-O-nicotinoyl-13,14-dihydroxymyrsinol (1), a diterpene ester with a myrsinol-type skeleton, isolated from Euphorbia decipiens Boiss. and Buhse, was un-competitive consistent with the molecular docking results. The Ki value was 117.40 +/- 0.7 microM.     

Pistagremic acid a new leishmanicidal triterpene isolated from Pistacia integerrima Stewart

The present study was designed to investigate the whole plant of Pistacia integerrima Stewart in order to examine the pharmacological basis of the use of the plant in folk medicine for the treatment of infectious diseases and disorder. Phytochemical and pharmacological studies led to the isolation of a new triterpene pistagremic acid (3-methyl-7-(4,4,10,13,14-pentamethyl-3-2,3,4,5,6,7,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)-oct-3-enoic). Pistagremic acid showed significant leishmanicidal activity (IC(50): 6.71 ± 0.09 μM) against Leishmania major (DESTO) promastigotes in comparison to standard compound amphotericin B (IC(50): 0.21 ± 0.06 μM).     

A randomized controlled trial of interventions to impede date palm sap contamination by bats to prevent nipah virus transmission in bangladesh

Background

Drinking raw date palm sap is a risk factor for human Nipah virus (NiV) infection. Fruit bats, the natural reservoir of NiV, commonly contaminate raw sap with saliva by licking date palm’s sap producing surface. We evaluated four types of physical barriers that may prevent bats from contacting sap.

Methods

During 2009, we used a crossover design and randomly selected 20 date palm sap producing trees and observed each tree for 2 nights: one night with a bamboo skirt intervention applied and one night without the intervention. During 2010, we selected 120 trees and randomly assigned four types of interventions to 15 trees each: bamboo, dhoincha (local plant), jute stick and polythene skirts covering the shaved part, sap stream, tap and collection pot. We enrolled the remaining 60 trees as controls. We used motion sensor activated infrared cameras to examine bat contact with sap.

Results

During 2009 bats contacted date palm sap in 85% of observation nights when no intervention was used compared with 35% of nights when the intervention was used [p<0.001]. Bats were able to contact the sap when the skirt did not entirely cover the sap producing surface. Therefore, in 2010 we requested the sap harvesters to use larger skirts. During 2010 bats contacted date palm sap [2% vs. 83%, p<0.001] less frequently in trees protected with skirts compared to control trees. No bats contacted sap in trees with bamboo (p<0.001 compared to control), dhoincha skirt (p<0.001) or polythene covering (p<0.001), but bats did contact sap during one night (7%) with the jute stick skirt (p<0.001).

Conclusion

Bamboo, dhoincha, jute stick and polythene skirts covering the sap producing areas of a tree effectively prevented bat-sap contact. Community interventions should promote applying these skirts to prevent occasional Nipah spillovers to human.     

Molecular variation at the SLC6A3 locus predicts lifetime risk of PTSD in the Detroit Neighborhood Health Study

Recent work suggests that the 9-repeat (9R) allele located in the 3'UTR VNTR of the SLC6A3 gene increases risk of posttraumatic stress disorder (PTSD). However, no study reporting this association to date has been based on population-based samples. Furthermore, no study of which we are aware has assessed the joint action of genetic and DNA methylation variation at SLC6A3 on risk of PTSD. In this study, we assessed whether molecular variation at SLC6A3 locus influences risk of PTSD. Participants (n?=?320; 62 cases/258 controls) were drawn from an urban, community-based sample of predominantly African American Detroit adult residents, and included those who had completed a baseline telephone survey, had provided blood specimens, and had a homozygous genotype for either the 9R or 10R allele or a heterozygous 9R/10R genotype. The influence of DNA methylation variation in the SLC6A3 promoter locus was also assessed in a subset of participants with available methylation data (n?=?83; 16 cases/67 controls). In the full analytic sample, 9R allele carriers had almost double the risk of lifetime PTSD compared to 10R/10R genotype carriers (OR?=?1.98, 95% CI?=?1.02-3.86), controlling for age, sex, race, socioeconomic status, number of traumas, smoking, and lifetime depression. In the subsample of participants with available methylation data, a significant (p?=?0.008) interaction was observed whereby 9R allele carriers showed an increased risk of lifetime PTSD only in conjunction with high methylation in the SLC6A3 promoter locus, controlling for the same covariates. Our results confirm previous reports supporting a role for the 9R allele in increasing susceptibility to PTSD. They further extend these findings by providing preliminary evidence that a "double hit" model, including both a putatively reduced-function allele and high methylation in the promoter region, may more accurately capture molecular risk of PTSD at the SLC6A3 locus.     

A novel moderately halophilic bacterium for decolorizing azo dye under high salt condition

Halomonas sp strain GTW was newly isolated from coastal sediments contaminated by chemical wastewater and was identified to be a member of the genus Halomonas by 16S rDNA sequence analysis and physical and biochemical tests. The optimal decolorization conditions were as follows: temperature 30°C, pH 6.5.0–8.5, NaCl 10–20% (w/v) and the optimal carbon source was yeast exact. The results of experiments demonstrated that the bacteria could decolorize different azo dyes under high salt concentration conditions, and the decolorization rate of five tested azo dyes could be above 90% in 24 h. The exploitation of the salt-tolerant bacteria in the bio-treatment system would be a great improvement of conventional biological treatment systems and the bio-treatment concept.     

Pharmacological activities of crude acetone extract and purified constituents of Salvia moorcraftiana Wall.

The crude acetone extract of aerial parts of Salvia moorcraftiana Wall. was screened for various biological activities including Lemna bioassay, antifungal, antibacterial, leishmanicidal, insecticidal activities and brine shrimp cytotoxicity. It was found to possess strong phytotoxic activity against Lemna aequinoctials Welve. and moderate antifungal activity against animal and plant pathogens. The purified chemical constituents were tested for enzyme inhibition activity. Two constituents (compounds 3 and 8) were found to be effective inhibitors of alpha-glucosidase.     

The halophilic alkalithermophile Natranaerobius thermophilus adapts to multiple environmental extremes using a large repertoire of Na+(K+)/H+ antiporters

Natranaerobius thermophilus is an unusual extremophile because it is halophilic, alkaliphilic and thermophilic, growing optimally at 3.5 M Na⁺, pH^55°C 9.5 and 53°C. Mechanisms enabling this tripartite lifestyle are essential for understanding how microorganisms grow under inhospitable conditions, but remain unknown, particularly in extremophiles growing under multiple extremes. We report on the response of N. thermophilus to external pH at high salt and elevated temperature and identify mechanisms responsible for this adaptation. N. thermophilus exhibited cytoplasm acidification, maintaining an unanticipated transmembrane pH gradient of 1 unit over the entire extracellular pH range for growth. N. thermophilus uses two distinct mechanisms for cytoplasm acidification. At extracellular pH values at and below the optimum, N. thermophilus utilizes at least eight electrogenic Na⁺(K⁺)/H⁺ antiporters for cytoplasm acidification. Characterization of these antiporters in antiporter-deficient Escherichia coli KNabc showed overlapping pH profiles (pH 7.8–10.0) and Na⁺ concentrations for activity ( K _0.5 values 1.0–4.4 mM), properties that correlate with intracellular conditions of N. thermophilus . As the extracellular pH increases beyond the optimum, electrogenic antiport activity ceases, and cytoplasm acidification is achieved by energy-independent physiochemical effects (cytoplasmic buffering) potentially mediated by an acidic proteome. The combination of these strategies allows N. thermophilus to grow over a range of extracellular pH and Na⁺ concentrations and protect biomolecules under multiple extreme conditions.