Screening of alginate lyase-producing bacteria and optimization of media compositions for extracellular alginate lyase production

Background: Alginate is a linear polysaccharide consisting of guluronate [polyG] and mannuronate [polyM] subunits

Methods: In the initial screening of alginate-degrading bacteria from soil, 10 isolates were able to grow on minimal medium containing alginate. The optimization of cell growth and alginate lyase [algL] production was carried out by the addition of 0.8% alginate and 0.2-0.3 M NaCl to the culture medium. Of 10 isolates, one was selected based on its fast growth rate on minimal 9 medium containing 0.4% sodium alginate. The selected bacterium, identified based on morphological and biochemical characteristics, as well as 16S rDNA sequence data, was confirmed to be an isolate belonging to the genus Bacillus and designated as Bacillus sp. TAG8

Results: The results showed the ability of Bacillus sp. TAG8 in utilizing alginate as a sole carbon source. Bacillus sp. TAG8 growth and algL production were augmented with an increase in sodium alginate concentration and also by the addition of 0.2-0.3 M NaCl. Molecular analysis of TAG8 algL gene showed 99% sequence identity with algL of Pseudomonas aeruginosa PAO1. The algL produced by Bacillus sp. TAG8 cleaved both polyM and polyG blocks in alginate molecule, as well as acetylated alginate residues, confirming the bifunctionality of the isolated lyase

Conclusion: The identification of novel algL genes from microbial communities constitutes a new approach for exploring lyases with specific activity against bacterial alginates and may thus contribute to the eradication of persistent biofilms from clinical samples

Production of xanthanases by paenibacillus spp.: complete xanthan degradation and possible applications

Background: A number of microorganisms and their enzymes have been reported as xanthan depolymerizers. Paenibacillus species are well-known polysaccharide hydrolyzing bacteria. However, Paenibacillus alginolyticus and Paenibacillus sp. XD are the only species in the genus which are now known to degrade xanthan

Objectives: Complete biodegradation of the xanthan exopolysaccharide is a rarely found capability among microorganisms. The aim of this study is to survey xanthanase producing bacteria with an appropriate bioactivity for the biopolymer degradation under different environmental conditions

Materials and Methods: The bacteria were isolated based on viscosity reduction of the xanthan solution. Bacterial isolates were identified using rep-PCR [repetitive element-based genomic fingerprinting] and 16S rDNA sequencing. Xanthanases were characterized by measuring their activity at different temperatures, pH values, and NaCl concentrations. Degradation of other polysaccharides and xanthan degradation products were investigated based on the screening plate method and TLC [thin-layer chromatography], respectively

Results: Six isolates from different Paenibacillus species with a complete xanthan degrading capability were isolated from Urmia Lake. Phylogenetic analysis placed these strains within the genus Paenibacillus with the closest relatives that were found to be P. nanensis, P. phyllosphaerae, P. agaridevorans, P. agarexedens, and P. taohuashanense. These isolates displayed different levels of the xanthan biodegradation activity in temperatures ranging from 15 to 55 [degree]C and pH values from 4 to 11. Xanthanolytic activity was generally prevented in presence of NaCl [> 0.1 mol.L-1]. Furthermore, the isolated Paenibacillus spp. could degrade several other polysaccharides including xylan, CMC [carboxymethyl cellulose], starch, alginate, and pectin

Conclusion: Novel strains of the six different Paenibacillus species that were introduced in the present study are able to produce xanthanases with interesting characteristics. In light of the results from this study, special applications, particularly in healthcare, medicine, and the environment is hereby proposed for these enzymes

[Genetic [or factors or variants] mechanisms for sensitivity to the anticoagulant warfarin]

Warfarin has been the mainstay of anticoagulation therapy for more than 50 years. Despite its proven efficacy and low cost, the clinical response to this agent is not predictable and the management of warfarin therapy is challenging because of the large variability in dose requirements and its side effects. Sensitivity to warfarin appears to be multifactorial and polygenic phenomenon. Genetic polymorphisms especially in CYP2C9 and VKORC1 in combination appear to have a major influence on sensitivity to warfarin. Age, sex, weight, disease state, diet, concomitant medications and ethnic affect sensitivity to warfarin. Despite to all limitations because of being multifactor sensitivity to warfarin, prospective studies of genotyping for CYP2C9 and VKORC1 of patients taking warfarin has the clear potential to determine the clinical safe dose of warfarin according to these genetic factors is a practicable goal and set a promising example of personalized medicine. Genetic and non genetic factors affecting sensitivity to warfarin are noticed in this article