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We have earlier reported a novel reductive pathway for o-nitrobenzoate (ONB) degradation (at 0.5 mM) in Arthrobacter protophormiae RKJ100, which proceeds via the formation of o-hydroxylaminobenzoate (HABA) and anthranilate (AA). During growth of this organism at 40 times higher concentration (20 mM) of ONB, 3-hydroxyanthranilate (HAA) was identified as an intermediate by thin layer chromatography, gas chromatography and high performance liquid chromatography studies. Crude cell extracts of ONB-grown cells showed HAA 3,4-dioxygenase activity suggesting HAA as a terminal aromatic intermediate of the catabolic energy-yielding pathway as shown before in Pseudomonas fluorescens strain KU-7. HAA is further cleaved to 2-amino-3-carboxymuconic-6-semialdehyde by the action of HAA 3,4-dioxygenase. In this report we propose that ONB degradation occurs via the formation of HABA and the pathway branches at this point to form the two different aromatic intermediates AA and HAA by the action of a reductase and a mutase, respectively. [ABSTRACT FROM AUTHOR]

Background: Bioethanol obtained by fermenting cellulosic fraction of biomass holds promise for blending in petroleum. Cellulose hydrolysis yields glucose while hemicellulose hydrolysis predominantly yields xylose. Economic feasibility of bioethanol depends on complete utilization of biomass carbohydrates and an efficient co-fermenting organism is a prerequisite. While hexose fermentation capability of Saccharomyces cerevisiae is a boon, however, its inability to ferment pentose is a setback.Results: Two xylose fermenting Kodamaea ohmeri strains were isolated from Lagenaria siceraria flowers through enrichment on xylose. They showed 61% glucose fermentation efficiency in fortified medium. Medium engineering with 0.1% yeast extract and peptone, stimulated co-fermentation potential of both strains yielding maximum ethanol 0.25 g g−1 on mixed sugars with ~ 50% fermentation efficiency. Strains were tolerant to inhibitors like 5-hydroxymethyl furfural, furfural and acetic acid. Both K. ohmeri strains grew well on biologically pretreated rice straw hydrolysates and produced ethanol.Conclusions: This is the first report of native Kodamaea sp. exhibiting notable mixed substrate utilization and ethanol fermentation. K. ohmeri strains showed relevant traits like utilizing and co-fermenting mixed sugars, exhibiting excellent growth, inhibitor tolerance, and ethanol production on rice straw hydrolysates. [ABSTRACT FROM AUTHOR]

Clostridium carboxidivorans strain P7T is a strictly anaerobic acetogenic bacterium that produces acetate, ethanol, butanol, and butyrate. The C. carboxidivorans genome contains all the genes for the carbonyl branch of the Wood-Ljungdahl pathway for CO2 fixation, and it encodes enzymes for conversion of acetyl coenzyme A into butanol and butyrate. [ABSTRACT FROM AUTHOR]

Oligotropha carboxidovorans OM5T (DSM 1227, ATCC 49405) is a chemolithoautotrophic bacterium with the capability to utilize carbon monoxide, carbon dioxide, and hydrogen. It is also capable of heterotrophic growth under appropriate environmental conditions. Here we report the annotated genome sequence of the circular chromosome of this organism. [ABSTRACT FROM AUTHOR]

More than 98% of reported human listeriosis cases are caused by Listeria monocytogenes serotypes within lineages I and II. Serotypes within lineage III (4a and 4c) are commonly isolated from environmental and food specimens. We report the first complete genome sequence of a lineage III isolate, HCC23, which will be used for comparative analysis. [ABSTRACT FROM AUTHOR]

FKBP22, an Escherichia coli -made peptidyl-prolyl cis - trans isomerase, has shown considerable homology with Mip-like virulence factors. While the C-terminal domain of this enzyme is used for executing catalytic function and binding inhibitor, the N-terminal domain is employed for its dimerization. To precisely determine the underlying factors of FKBP22 dimerization, its structural model, developed using a suitable template, was carefully inspected. The data show that the dimeric FKBP22, like dimeric Mip proteins, has a V-like shape. Further, it dimerizes using 40 amino acid residues including Ile 9, Ile 17, Ile 42, and Ile 65. All of the above Ile residues except Ile 9 are partly conserved in the Mip-like proteins. To confirm the roles of the partly conserved Ile residues, three FKBP22 mutants, constructed by substituting them with an Ala residue, were studied as well. The results together indicate that Ile 65 has little role in maintaining the dimeric state or enzymatic activity of FKBP22. Conversely, both Ile 17 and Ile 42 are essential for preserving the structure, enzymatic activity, and dimerization ability of FKBP22. Ile 42 in particular looks more essential to FKBP22. However, none of these two Ile residues is required for binding the cognate inhibitor. Additional computational studies also indicated the change of V-shape and the dimeric state of FKBP22 due to the Ala substitution at position 42. The ways Ile 17 and Ile 42 protect the structure, function, and dimerization of FKBP22 have been discussed at length.Communicated by Ramaswamy H. Sarma.

Background: Colistin was considered as the most effective antibiotic against Acinetobacter baumannii, a widely-known opportunistic pathogen. In recent years, a number of colistin resistant strains have also been reported., Objective: This work is commenced to investigate the contribution of efflux pumps toward resistance to colistin-like cyclic polypeptide antibiotics, since the efflux pumps serve as the escape routes leading to drug-resistance., Methods: RNA was extracted from A. baumannii isolates cultured from samples procured by tracheal aspiration of infected patients. The expressions of gene(s) that played major roles in the regulation of efflux pump families and involvement of integron systems were studied using real time PCR. Antimicrobial susceptibility tests were conducted to investigate antibiotic resistance of the isolates., Results: It was observed that genes coding for sugE, ydhE, ydgE, mdfA, ynfA and tolC significantly contributed to resistance against colistin antibiotics, however, no significant transcriptional change was observed in the efflux pump, MexAB-OprM. Results suggest that A. baumanii readily pumps out colistin via efflux pumps belonging to MATE and SMR family., Conclusion: Integral role of efflux pumps and integron 1 genetic system was elucidated towards evolution of multi-drug resistant strain(s). Therefore, for accurate therapeutics, an early detection of efflux genes is crucial before prescribing against colistin resistant A. baumanii., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

The chlorinated insecticide hexachlorocyclohexane (HCH) has been used extensively in the past, and contaminated sites are present throughout the world. Toward their bioremediation, we isolated a bacterium Pseudomonas aeruginosa ITRC-5 that mediates the degradation of all the four major isomers of HCH under aerobic conditions, both in liquid-culture and contaminated soils. In liquid-culture, the degradation of alpha- and gamma-HCH is rapid and is accompanied with the release of 5.6 micromole chloride ions and 4.1 micromole CO2 micromole(-1) HCH-isomer. The degradation of beta- and delta-isomers is slow, accompanied with the release of 0.9 micromole chloride ions micromole(-1) HCH-isomer, and results in a transient metabolite 2,3,4,5,6-pentachlorocyclohexan-1-ol. The strain ITRC-5 also mediates the degradation of alpha-, beta-, gamma-, and delta-isomers in contaminated soils, where degradation of otherwise persistent beta- and delta-HCH is enhanced severalfold in the presence of alpha- or gamma-HCH. The degradation of soil-applied beta- and delta-HCH under aerobic conditions has not been reported earlier. The isolate ITRC-5 therefore demonstrates potential for the bioremediation of HCH-wastes and contaminated soils.