Abstract Synthetic polymers have long been used to modify various properties of proteins such as activity and solubility. Polyethylene glycol (PEG) has been widely used to form adducts with enzymes and antibodies. In this study, the polyoxazoline family of water‐soluble polymers was used to synthesize adducts containing a synthetic peptide recognized by a monoclonal antibody (MAb) directed against human protein C (hPC). This is the first application of direct conjugation of unterminated or “living” polymer to a peptide. The avidity of the antibody for the various adducts was characterized with respect to size and hydrophilicity of methyl‐ and ethyl‐substituted polyoxazoline polymers (POX). Avidity of the adducts was not found to be dependent upon the hydrophilicity and was slightly decreased due to polymer modification. The methyl‐POX‐peptide adducts were found to be highly water soluble, while the ethyl‐POX‐peptide adducts showed sporadic problems with aqueous solubility. Because the polymer‐peptide adducts retained avidity for the antibody, polyoxazoline polymers may have potential application to protein‐adduct chemistry.
RBx 11760, a novel oxazolidinone, was investigated for in vitro and in vivo activity against Clostridium difficile. The in vitro activity of RBx 11760 and three other agents against 50 diverse C. difficile clinical isolates and other obligate anaerobic bacteria was determined. The effect of RBx 11760 on sporulation and toxin production was determined against different C. difficile isolates. We used a hamster infection model to investigate the efficacy of RBx 11760, vancomycin and metronidazole. The mechanism of action of RBx 11760 against C. difficile ATCC 43255 was determined by macromolecular synthesis inhibition. RBx 11760 MICs were in the range of 0.5–1 mg/L for C. difficile isolates, and it demonstrated concentration-dependent killing of C. difficile ATCC 43255 and C. difficile 6387 up to 2–4× MIC (1–2 mg/L). RBx 11760, at concentrations as low as 0.25–0.5 mg/L, resulted in a significant reduction in de novo toxin production as well as sporulation in different C. difficile isolates. In contrast, vancomycin, metronidazole and linezolid had little or no effect on toxin production and appeared to promote the formation of spores. In the hamster infection model, treatment with RBx 11760 resulted in prolonged survival of animals as compared with vancomycin or metronidazole, which correlated well with the histopathology results. Macromolecular labelling results suggest that RBx 11760 is a potent inhibitor of bacterial protein synthesis. RBx 11760 showed excellent in vitro and in vivo activity against C. difficile, and it could be a promising novel candidate for future drug development against C. difficile infection.
C. freundii, a member of Enterobacteriaceae was isolated from nearby sewage and characterised. With optimum conditions, its hydrogen production capacity and efficiency was tested in synthetic medium containing glucose as carbon and energy source. C. freundii was grown in a 51 fermentor under batch anaerobic conditions. The total production of gas was 8.91 in the volumetric ratio of 63% H2 and 37% CO2 in 11 hr from 30.8 g glucose. From 1 mole of glucose 1.286 mole of hydrogen was produced (YH2/s). The rate of gas production (rQ) and hydrogen production (rH2) was 0.71 and 0.45 1/hr respectively. The strain appears to be a better one for hydrogen production compared to the earlier Citrobacter spp reported.
Chitosan is a natural biopolymer whose rich amine functionality confers water solubility at low pH. At higher pH's (greater than 6. 5), the amines are deprotonated and chitosan is insoluble. To attain water solubility under basic conditions we enzymatically grafted the hydrophilic compound chlorogenic acid onto chitosan. Despite its name, chlorogenic acid is a nonchlorinated phenolic natural product that has carboxylic acid and hydroxyl functionality. The enzyme in this study was tyrosinase, which converts a wide range of phenolic substrates into electrophilic o-quinones. The o-quinones are freely diffusible and can undergo reaction with the nucleophilic amino groups of chitosan. Using slightly acidic conditions (pH = 6), it was possible to modify chitosan under homogeneous conditions. When the amount of chlorogenic acid used in the modification reaction exceeded 30% relative to chitosan's amino groups, the modified chitosan was observed to be soluble under both acidic and basic conditions, and to have a pH window of insolubility at near neutral pH. 1H NMR spectra confirmed that chitosan was chemically modified, although the degree of modification was low. Copyright 1999 John Wiley & Sons, Inc.
Using analogies from nature, we investigated the possibility that tyrosinase-catalyzed reactions of 3,4-dihydroxyphenethylamine (dopamine) could confer water-resistant adhesive properties to semidilute solutions of the polysaccharide chitosan. Rheological measurements showed that the tyrosinase-catalyzed, and subsequent uncatalyzed, reactions lead to substantial increases in the viscosity of the chitosan solutions. Samples from these high-viscosity modified-chitosans were spread onto dry glass slides, the slides were lapped and clipped together either in air or after being submerged in water, and the bound slides were held under water for several hours. Adhesive shear strengths of over 400 kPa were observed for these modified chitosan samples, while control chitosan solutions conferred no adhesive strength (i.e., the glass slides separated in the absence of measurable forces). High viscosities and water-resistant adhesive strengths were also observed when semidilute chitosan solutions were treated with the known cross-linking agent, glutaraldehyde. Further studies indicate a relationship between the increased viscosities and water-resistant adhesion. These results demonstrate that the renewable biopolymer chitosan can be converted into a water-resistant adhesive.
_____________________________________________________________________________________________ ABSTRACT Biodiesel has turned into the need of the hour with the massively expanding transportation sector. With the shrinking scope of fossil fuel reliance newer options such as green plants were targeted as the alternative source. The first and second generation biofuel resources comprised the edible and non-edible plants. Since these plants were competing with the food and land availability the third generation biofuel source was selected meticulously to overcome these disadvantages. Thus algae were the ultimate choice as its growth requirements were limited to marine or freshwater, least fertile terrain and sunlight. Several algal species, including both macroalgae and microalgae are studied extensively for their hydrocarbon producing capacity. Sargassum, Chlorella vulgaris, Botryococcus braunii, Chlamydomonas and Desmococcus olivaceous are some of the algal species which are targeted for various reasons. Botryococcus braunii is a green, microalgae known for its high hydrocarbon content. In this study, we have attempted to analyze the transcriptome data of two races of B braunii. The transcriptome data was subject to pre-processing as it contains some low quality reads. After the quality check the obtained high quality reads were assembled using Trinity transcriptome assembler. The short reads were assembled into contigs. These contigs were further annotated using BlastX. The reads with the homologous hits were analyzed for the presence of enzymes involved in the hydrocarbon biosynthesis. Hence, in this study, we were able to map the transcripts corresponding to the enzymes involved in various pathways. Keywords: Algae, Biodiesl, Botryococcus braunii , NGS, Transcriptome. _____________________________________________________________________________________________ INTRODUCTION Locomotion is vital for human survival, hence fuel consumption in the transport sector ranges up to 80% of total fuel usage. The demographic growth and fuel accessibility are continually being contrarily corresponding. In recent times fuel has become the symbol of economic threat as India imports 90% of crude oil from oil producing countries [1]. To handle this disparity the quest for alternative fuel resources have coordinated towards the green assets, the plants and green growth. The initial two generations of biodiesel sources were the edible and non-edible plants [2]. The sources were rivaling nourishment yields and land accessibility. Presently, the third generation biofuel resources are centered towards the microalgal biomass [3]. Green growth can develop effortlessly in less fertile terrains with the accessibility to daylight and water. This allowed researchers to characterize the algae and optimize methods for their growth. Algae with a total of 139,704 species as reported in Algabase [url http://www.algaebase.org/] has been classified into macroalgae and microalgae. According to 2012 reports, researchers across the globe have started investigating
A number of microorganisms were selected from soil and sediment samples which were known to have been previously exposed to nitrate ester contaminants. The two most effective bacteria for transforming glycerol trinitrate (GTN) were identified as Bacillus thuringiensis/cereus and Enterobacter agglomerans. For both isolates, denitration activities were expressed constitutively and GTN was not required for induction. Dialysis of cell extracts from both isolates did not affect denitration, which indicates that dissociable and depletable cofactors are not required for denitration. With thin-layer chromatography and high-performance liquid chromatography, the denitration pathway for both isolates was shown to be a sequential denitration of GTN to glycerol dinitrate isomers, glycerol mononitrate isomers, and ultimately to glycerol. GTN was observed to be completely converted to glycerol during a long-term incubation of cell extracts.
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