Carotenoid Production by a Novel Isolate of <Emphasis Type="Italic">Microbacterium paraoxydans</Emphasis>

This study reports extraction and characterization of carotenoid pigments from Microbacterium paraoxydans, a non-photosynthetic bacterium, cultivated in Luria–Bertani (LB) medium. The isolate was identified to be moderately halo- and osmo-tolerant capable of withstanding high (~ 6%) salt and sugar (30% w/v sucrose, 20% w/v glucose) concentrations after a brief period of adaptation. The pigments were characterized using a combination of UV–Vis spectral analysis with the λ_max at 407, 436 and 466 nm and ESI–MS with an m/z value at 536.44. The absorption profile of the pigments and their nature was influenced by carbon, nitrogen source and presence of salt in the growth medium. Highest level of pigment (~ 16 g kg dry wt cells^?1) was produced in NH₄Cl supplemented LB medium. The pigment displayed free radical scavenging, anticancer activity, characteristic of the plant carotenoids. Based on the accumulation of pigments under different conditions, a biochemical pathway for synthesis of neurosporene was proposed.     

Adenosine A(1) receptors mediate plasma exudation from the oral mucosa.

The purpose of this study was to pharmacologically characterize the adenosine receptor subtype(s) that mediates adenosine-induced increases in macromolecular efflux from the intact hamster cheek pouch. Using intravital microscopy, we found that 1,3-dipropyl-8-(2-amino-4-chlorophenyl)-xanthine (PACPX), a selective adenosine receptor-1 antagonist, but not 3,7-dimethyl-1-propargylxanthine (DMPX), a selective adenosine receptor-2 antagonist, significantly attenuated adenosine-induced leaky site formation and increased clearance of fluorescein isothiocyanate-labeled dextran (molecular mass, 70 kDa) from the intact hamster cheek pouch (P < 0.05). Both compounds had no significant effects on bradykinin-induced responses. Nanomolar concentrations of R(-)-N(6)-(2-phenylisopropyl)-adenosine [R(-)-PIA], a selective adenosine A(1) agonist, evoked significant, concentration-dependent increases in macromolecular efflux. This response was significantly attenuated by PACPX but not by DMPX. In contrast, CGS-21680, a selective adenosine A(2) agonist, increased macromolecular efflux but only at micromolar concentrations. This response was significantly attenuated by DMPX but not by PACPX. Suffusion of nitroglycerin had no significant effects on R(-)-PIA- and CGS-21680-induced responses. In addition, suffusion of N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, had no significant effects on adenosine-induced responses. Indomethacin had no significant effects on adenosine-, R(-)-PIA-, and CGS-21680-induced increases in macromolecular efflux. Collectively, these data indicate that adenosine increases macromolecular efflux from the intact hamster cheek pouch by stimulating high-affinity adenosine A(1) receptors in a specific, nitric oxide- and prostaglandin-independent fashion.     

Cloning, characterization, and functional expression of a CNP receptor regulating CFTR in the shark rectal gland

In the shark, C-type natriuretic peptide (CNP) is the onlycardiac natriuretic hormone identified and is a potent activator ofCl secretion in the rectalgland, an epithelial organ of this species that contains cysticfibrosis transmembrane conductance regulator (CFTR) Clchannels. We have cloned an ancestral CNP receptor (NPR-B) from theshark rectal gland that has an overall amino acid identity to the humanhomologue of 67%. The shark sequence maintains six extracellular Cyspresent in other NPR-B but lacks a glycosylation site and a Glu residuepreviously considered important for CNP binding. When shark NPR-B andhuman CFTR were coexpressed in Xenopus oocytes, CNP increased the cGMP content of oocytes(EC₅₀ 12 nM) and activated CFTRCl channels(EC₅₀ 8 nM). Oocyte cGMP increased36-fold (from 0.11 ± 0.03 to 4.03 ± 0.45 pmol/oocyte) andCl current increased37-fold (from 34 ± 14 to 1,226 ± 151 nA) in thepresence of 50 nM CNP. These findings identify the specific natriureticpeptide receptor responsible forCl secretion in the sharkrectal gland and provide the first evidence for activation of CFTRCl channels by a clonedNPR-B receptor.     

Molecular docking analysis of modified gedunin from neem with snake venom enzymes

Snakebites are a problem due to the increasing number of deaths and permanent disabilities. There is currently a shortage of antidotes for snakebite. The existing antibody antidote, produced from horse/sheep plasma/sera is expensive, species-dependent, and causes fatal side effects. Therefore, it is of interest use of natural flavonoid named gedunin from the Azadirachta indica (Neem) plant species to combat snakebites. Thus, we show the molecular docking analysis of gedunin (C26H31N2O6F) with enzymes (common in snake species) such as 5-nucleotidase, acetyl cholinesterase, L-aao, metalloproteinase, serine, thrombin and phospholipase A2. The modified gedunin in the enzyme pocket showed improved pharmacological properties for further consideration in combating snakebites.     

Systematic mutagenesis of the Saccharomyces cerevisiae MLH1 gene reveals distinct roles for Mlh1p in meiotic crossing over and in vegetative and meiotic mismatch repair

In eukaryotic cells, DNA mismatch repair is initiated by a conserved family of MutS (Msh) and MutL (Mlh) homolog proteins. Mlh1 is unique among Mlh proteins because it is required in mismatch repair and for wild-type levels of crossing over during meiosis. In this study, 60 new alleles of MLH1 were examined for defects in vegetative and meiotic mismatch repair as well as in meiotic crossing over. Four alleles predicted to disrupt the Mlh1p ATPase activity conferred defects in all functions assayed. Three mutations, mlh1-2, -29, and -31, caused defects in mismatch repair during vegetative growth but allowed nearly wild-type levels of meiotic crossing over and spore viability. Surprisingly, these mutants did not accumulate high levels of postmeiotic segregation at the ARG4 recombination hotspot. In biochemical assays, Pms1p failed to copurify with mlh1-2, and two-hybrid studies indicated that this allele did not interact with Pms1p and Mlh3p but maintained wild-type interactions with Exo1p and Sgs1p. mlh1-29 and mlh1-31 did not alter the ability of Mlh1p-Pms1p to form a ternary complex with a mismatch substrate and Msh2p-Msh6p, suggesting that the region mutated in these alleles could be responsible for signaling events that take place after ternary complex formation. These results indicate that mismatches formed during genetic recombination are processed differently than during replication and that, compared to mismatch repair functions, the meiotic crossing-over role of MLH1 appears to be more resistant to mutagenesis, perhaps indicating a structural role for Mlh1p during crossing over.     

An 11p15 imprinting centre region 2 deletion in a family with Beckwith Wiedemann syndrome provides insights into imprinting control at CDKN1C

We report a three generation family with Beckwith Wiedemann syndrome (BWS) in whom we have identified a 330 kb deletion within the KCNQ1 locus, encompassing the 11p15.5 Imprinting Centre II (IC2). The deletion arose on the paternal chromosome in the first generation and was only associated with BWS when transmitted maternally to subsequent generations. The deletion on the maternal chromosome was associated with a lower median level of CDKN1C expression in the peripheral blood of affected individuals when compared to a cohort of unaffected controls (p<0.05), however was not significantly different to the expression levels in BWS cases with loss of methylation (LOM) within IC2 (p<0.78). Moreover the individual with a deletion on the paternal chromosome did not show evidence of elevated CDKN1C expression or features of Russell Silver syndrome. These observations support a model invoking the deletion of enhancer elements required for CDKN1C expression lying within or close to the imprinting centre and importantly extend and validate a single observation from an earlier study. Analysis of 94 cases with IC2 loss of methylation revealed that KCNQ1 deletion is a rare cause of loss of maternal methylation, occurring in only 3% of cases, or in 1.5% of BWS overall.     

Ribosomal ITS1 sequence-based diversity analysis of anaerobic rumen fungi in cattle fed on high fiber diet

Fiber degradation in the ruminant digestive process is a major activity accomplished by rumen microbes, a process in which the role of fungi is important. Therefore, the present study was conducted to establish the community structure of anaerobic rumen fungi in cattle fed on a high fiber diet using molecular approaches. Total community DNA was extracted, and the ribosomal internal transcribed spacer (ITS) 1 region was amplified, cloned, and sequenced. The resulting nucleotide sequences were used to construct a phylogenetic tree. A total of 52 clones were analyzed, revealing 31 different ITS1 gene phylotypes. Of these, 12 belonged to the genus Orpinomyces (48 % of clones), followed by uncultured Neocallimastigale clones (29 %), Cyllamyces spp. (9 %) and Anaeromyces spp. (8 %). Our results indicate that genus Orpinomyces dominates the rumen fungal community in Indian crossbred Karan Fries cattle.