Phylogenetic diversity and biotechnological potentials of marine bacteria from continental slope of eastern Arabian Sea

Marine environments are substantially untapped source for the isolation of bacteria with the capacity to produce various extracellular hydrolytic enzymes, which have important ecological roles and promising biotechnological applications. Hydrolases constitute a class of enzymes widely distributed in nature from bacteria to higher eukaryotes. Marine microbial communities are highly diverse and have evolved during extended evolutionary processes of physiological adaptations under the influence of a variety of ecological conditions and selection pressures. A number of marine hydrolases have been described, including amylases, lipases and proteases, which are being used extensively for biotechnological applications. The present study was carried out to isolate marine bacteria from continental slope sediments of the eastern Arabian Sea and explore their biotechnological potential. Among the 119 isolates screened, producers of amylases (15%), caseinases (40%), cellulases (40%), gelatinases (60%), lipases (26%), ligninases (33%), phytase (11%) and Malachite Green dye degraders (16%) were detected. Phylogenetic analysis based on 16S rRNA gene sequencing showed that predominant marine sediment bacteria possessing more than four enzymatic activities belonged to the phyla Firmicutes and Proteobacteria, was assigned to the genera Bacillus, Planococcus, Staphylococcus, Chryseomicrobium, Exiguobacterium and Halomonas. Biodegradation of the dye Malachite Green using the liquid decolorization assay showed that both the individual cultures (Bacillus vietnamensis, Planococcus maritimus and Bacillus pumilus) and their consortium were able to decolorize more than 70% of dye within 24?h of incubation. This is the first report on diversity and extracellular hydrolytic enzymatic activities and bioremediation properties of bacteria from continental slope sediment of eastern Arabian Sea.     

Novel classes of fatty acid and retinol binding protein from nematodes

Parasitic nematodes have recently been found to produce proteins which represent two new classes of fatty acid and retinoid binding protein. The first is the nematode polyprotein allergens/antigens (NPAs) which, as their name suggests, are synthesised as large polyproteins which are subsequently cleaved at regularly spaced sites to form multiple copies of a fatty acid binding protein of approximately 14.5 kDa. Binding studies using molecular environment-sensitive fluorescent ligands have shown that the binding site is highly unusual, producing blue-shifting in fluorescence to an unprecedented degree, suggesting a remarkably non-polar environment and isolation from solvent water. Computer-based structural predictions and biophysical observations have identified the NPAs as highly helical proteins which might form a four helix bundle, so constitute a new class of lipid binding protein from animals. The second class, like the NPAs, binds both fatty acids and retinol, but with a higher affinity for the latter. These are also highly helical but are structurally distinct from the NPAs. The biological function of these new classes of protein are discussed in the context of both the metabolic requirements of the parasites and the possible role of the proteins in control of the immune and inflammatory environment of the tissue sites parasitised.     

Evidence for a common mucosal immunologic system. I. Migration of B immunoblasts into intestinal, respiratory, and genital tissues.

The origins of immunoglobulin-containing cells in intestinal, respiratory, mammary, and genital tissues were studied in CBA/J female mice by using an adoptive lymphocyte transfer method. Within 24 hr after transfer, [3H]thymidine-labeled donor mesenteric lymph node (MLN) cells were observed in recipient gut, cervix and vagina, uterus, mammary glands, and MLN, where approximately 60% contained IgA and 25% IgG. In peripheral lymph nodes (PLN), 44% of the labeled cells after MLN transfer contained IgG, whereas only 8% were of the IgA isotype. The preference of the MLN to populate mucosal sites was clear from the results. Labeled PLN cells were transferred and the majority of these returned to their sites of origin and contained IgG. Of the small number of labeled PLN cells found in mucosal tissues, approximately equal percentages (30%) of IgA- anti IgG-containing cells were seen. Dividing cells prepared from mediastinal (bronchial) lymph nodes (BLN) showed a propensity to localize in the lungs rather than the intestine. However, the predominant immunoglobulin content of these donor cells in gut, lungs, and MLN was IgA. In recipient PLN, most labeled BLN cells contained IgG. These data support the concept of a common mucosal immunologic system.     

Identification of B2 Bradykinin Binding Sites on Cultured Cortical Astrocytes

Bradykinin was found to bind to specific high-affinity sites in cultured cortical astrocytes from rat brain, and this binding appeared to be specific for the B2 bradykinin receptor subtype. Nonlinear regression analysis of saturation experiments using a computer programme revealed a single KD of 16.6 +/- 2.6 nM and a Bmax of 352.2 +/- 30.7 fmol/mg of protein. These results indicate that astrocytes possess bradykinin receptors and that these are predominantly of the B2 subtype.     

Differentiation of isolates of Discula umbrinella (Teleomorph: Apiognomonia errabunda) from beech, chestnut, and oak using randomly amplified polymorphic DNA markers.

Genetic variation in 30 isolates of Discula umbrinella derived from beech, chestnut, and oak was assessed using randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphic markers. Polymerase chain reaction amplifications with 17 primers produced 134 different DNA fragments. Three RAPD fragments were subsequently used for Southern hybridization. By these techniques up to four different individuals could be detected in the same leaf. The presence of several individuals within a single leaf indicates a finely tuned balance between the endophyte and its host. Cluster analysis of all arbitrary primed amplified DNA fragments showed that the isolates could be placed into four groups corresponding to their host origin. The high percentage of private RAPD variants within groups is consistent with low gene flow.