Variations in angiotensin-converting enzyme gene insertion/deletion polymorphism in Indian populations of different ethnic origins

The pattern of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in the Indian population is poorly known. In order to determine the status of the polymorphism, young unrelated male army recruits were screened. The population had cultural and linguistic differences and lived in an environment that varied significantly from one region to another. Analysis of the genotype, showed higher frequency of the insertion allele in four of the five groups i.e. I allele frequency was significantly higher (P< 005) in Dogras, Assamese and Kumaonese. The deletion allele frequency was comparatively higher in the fifth group that belonged to Punjab. A correlation was observed between the genotype and enzyme activity. Involvement of a single D allele in the genotype enhanced the activity up to 37.56 ± 313%. The results suggested ethnic heterogeneity with a significant gene cline with higher insertion allele frequency. Such population-based data on various polymorphisms can ultimately be exploited in pharmacogenomics.     

On Neodiaptomus schmackeri (Poppe & Richard, 1892) (Crustacea,Copepoda)

Neodiaptomus schmackeri and related species are redescribed. The synonymy of this species with N. strigilipes and N. handeli is discussed.     

Mercuric Ion Stabilizes Levansucrase Secreted by <Emphasis Type="Italic">Acetobacter nitrogenifigens</Emphasis> Strain RG1<Superscript>T</Superscript>

The purification and characterization of an extracellular levansucrase enzyme produced by novel nitrogen-fixer Acetobacter nitrogenifigens strain RG1^T is described. Culture conditions were optimized for maximum levansucrase production. Levansucrase purified to homogeneity by tenfold purification has a molecular weight of 65 kDa, contained four cysteine residues, polymerized raffinose and was stable for 21 days at pH 6.0 when stored at 4 °C or −20 °C but was vulnerable to DTT and β-mercaptoethanol. Interestingly, this enzyme showed enhanced hydrolytic and polymerization activity in the presence of mercuric ion which, to our knowledge, is the first report for any levansucrase enzyme characterized so far. Evidences obtained from Native PAGE, tryptophan fluorescence study and activity measurements at different temperatures and in the presence of thiol modifying agents, show that mercuric ion stabilizes the enzyme. Levan, synthesized by the enzyme, has a molecular weight of 7,080 kDa and was shown to be a homopolymer of fructose.     

Nitric oxide reduces sickle hemoglobin polymerization: potential role of nitric oxide-induced charge alteration in depolymerization

We previously demonstrated that inhaling nitric oxide (NO) increases the oxygen affinity of sickle red blood cells (RBCs) in patients with sickle cell disease (SCD). Our recent studies found that NO lowered the P₅₀ values of sickle hemoglobin (HbS) hemolysates but did not increase methemoglobin (metHb) levels, supporting the role of NO, but not metHb, in the oxygen affinity of HbS. Here we examine the mechanism by which NO increases HbS oxygen affinity. Because anti-sickling agents increase sickle RBC oxygen affinity, we first determined whether NO exhibits anti-sickling properties. The viscosity of HbS hemolysates, measured by falling ball assays, increased upon deoxygenation; NO treatment reduced the increment. Multiphoton microscopic analyses showed smaller HbS polymers in deoxygenated sickle RBCs and HbS hemolysates exposed to NO. These results suggest that NO inhibits HbS polymer formation and has anti-sickling properties. Furthermore, we found that HbS treated with NO exhibits an isoelectric point similar to that of HbA, suggesting that NO alters the electric charge of HbS. NO–HbS adducts had the same elution time as HbA upon high performance liquid chromatography analysis. This study demonstrates that NO may disrupt HbS polymers by abolishing the excess positive charge of HbS, resulting in increased oxygen affinity.     

Proteasome inhibition protects HT22 neuronal cells from oxidative glutamate toxicity

Oxidative stress caused by glutathione depletion after prolonged exposure to extracellular glutamate leads to a form of neuronal cell death that exhibits morphologically mixed features of both apoptosis and necrosis. However, specific downstream executioners involved in this form of cell death have yet to be identified. We report here that glutamate exposure does not activate caspase-3 in the HT22 neuronal cell line. Furthermore, no cytoprotection was achieved with either the pan-caspase inhibitor Z-VAD-fmk or the caspase-3-specific inhibitor DEVD-CHO. In contrast, inhibition of the proteasome by lactacystin protected both HT22 cells and rat primary neuronal cells against cell lysis. In parallel, oxidatively altered and ubiquitinated proteins accumulated in the mitochondrial fraction of cells after proteasome inhibition. These findings suggest that caspases can be decoupled from oxidative stress under some conditions, and implicate the ubiquitin/proteasome pathway in neuronal cell death caused by oxidative glutamate toxicity.     

Isolation of an unusual metabolite 2-allyloxyphenol from a marine actinobacterium, its biological activities and applications

A marine actinobacterium isolated from the Bay of Bengal, India and previously found to be producing an antimicrobial and cytotoxic terpenoid was further investigated for antimicrobial metabolites. The bacterium was preliminarily identified as a new species of the genus Streptomyces (strain MS1/7). The cell-free culture broth was extracted with n-butanol and purified using silica gel column chromatography and high-performance liquid chromatography. Molecular characterization was done using ESI mass, IR and ¹H and ¹³C NMR spectrometry. 2-Allyloxyphenol (MW 150; C₉H₁₀O₂), a synthetic drug and chemical intermediate, was obtained as a natural product for the first time. Serendipitous natural occurrence provided new insights into the synthetic molecule. 2-Allyloxyphenol was found to be inhibitory to 21 bacteria and three fungi in the minimum range 0.2–1.75 mg mL⁻¹ determined by agar dilution method. 2-Allyoxyphenol possesses strong antioxidant property (IC₅₀ 22 μg mL⁻¹, measured by 1, 1-diphenyl-2-picryl hydrazyl scavenging activity). Hydroxyl and allyloxy groups in 2-allyloxyphenol were responsible for antimicrobial and antioxidant activities. 2-Allyloxyphenol has marked resemblance to smoky aroma and is two to three times more active as an antimicrobial than some commercial smoke-flavour compounds. Absence of hemolytic toxicity, potential carcinogenicity, cytotoxicity and reports of toxic reactions in literature suggest possible application of 2-allyloxyphenol as a food preservative and an oral disinfectant.     

Characterization and emulsifying property of a carbohydrate polymer produced by Bacillus pumilus UW-02 isolated from waste water irrigated agricultural soil

Bacillus pumilus UW-02, an isolate from agricultural soil irrigated with waste water was found to produce a carbohydrate polymer in the form of extracellular polysaccharide (EPS) in glucose mineral salts medium (GMSM). The recovery rates of EPS by ion-exchange and gel filtration chromatography were around 63% and 90%, respectively. As evident from HPLC and FT-IR analyses, the EPS was found to be a heteropolymer consisting glucose, mannose, xylose, arabinose, and N-acetyl glucosamine as monomer units. Different oligosaccharide combinations namely hexose(4), hexose(6) pentose(1) and hexose(10) pentose(1) are obtained after partial hydrolysis of EPS using MALDI-ToF-MS. Electron micrographs portrayed the intense affinity of the EPS molecules for each other, thereby justifying its viscosifying and thickening properties. The EPS with an average molecular weight of 218 kDa and thermal stability up to 180 °C showed pseudoplastic rheology and significant emulsifying activities.