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Biomedical subjects

A B Banerjee

Publications and source records attributed to A B Banerjee.

At least 19 recordsLinked to original sources
PubMed2002

A new method of colorimetric assay of beta-lactamase suitable for estimation of beta-lactamase inhibition in crude microbial culture filtrates.

A simple procedure is described for the rapid assay of beta-lactamases suitable for use in the quantitation of beta-lactamase inhibition in crude culture filtrates of soil microbes. The proposed method is based on measuring the blue reaction product (lambda max 750 nm) formed during reduction of phosphomolybdic acid with reducing products generated from beta-lactam hydrolysis and is not influenced significantly by the metabolites of microbial culture filtrates which often interfere with conventional beta-lactamase assay techniques.

Actinobacteria↗
PubMed1999

Antimicrobial screening of some Indian spices.

In India, spices have been traditionally used since ancient times, for the preservation of food products as they have been reported to have antiseptic and disinfectant properties. In this respect, a preliminary screening for antimicrobial activities of 35 different Indian spices has been carried out. Of the spices surveyed, the results indicate that clove, cinnamon, bishop's weed, chilli, horse raddish, cumin, tamarind, black cumin, pomegranate seeds, nutmeg, garlic, onion, tejpat, celery, cambodge, have potent antimicrobial activities against the test organisms Bacillus subtilis (ATCC 6633), Escherichia coli (ATCC 10536) and Saccharomyces cerevisiae (ATCC 9763). The results also establish the traditional use of spices as food preservatives, disinfectants and antiseptics.

Anti-Bacterial Agents↗
PubMed1996

Reduction of methylglyoxal in Escherichia coli K12 by an aldehyde reductase and alcohol dehydrogenase.

Two enzymes, one NADPH-dependent and another NADH-dependent which catalyze the reduction of methylglyoxal to acetol have been isolated and substantially purified from crude extracts of Escherichia coli K12 cells. Substrate specificity and formation of acetol as the reaction product by both the enzymes, reversibility of NADH-dependent enzyme with alcohols as substrates and inhibitor study with NADPH-dependent enzyme indicate that NADPH-dependent and NADH-dependent enzymes are identical with an aldehyde reductase (EC 1.1.1.2) and alcohol dehydrogenase (EC 1.1.1.1) respectively. The K(m) for methylglyoxal have been determined to be 0.77 mM for NADPH-dependent and 3.8 mM for NADH-dependent enzyme. Stoichiometrically equimolar amount of acetol is formed from methylglyoxal by both NADPH- and NADH-dependent enzymes. In phosphate buffer, both the enzymes are active in the pH range of 5.8-6.6 with no sharp pH optimum. Molecular weight of both the enzymes were found to be 100,000 +/- 3,000 by gel filtration on a Sephacryl S-200 column. Both NADPH- and NADH-dependent enzymes are sensitive to sulfhydryl group reagents.

Alcohol Dehydrogenase↗
PubMed1996

Rapid ultraviolet spectrophotometric determination of bronopol: application to raw material analysis and kinetic studies of bronopol degradation.

A simple and rapid spectrophotometric assay is described for bronopol determination in raw material. The method is based on the measurement of absorbance (at 244 nm) of bromonitroethanol (sodium salt of aci-form), the chromophoric derivative formed from bronopol instantaneously by a retroaldol reaction in the presence of 0.1 M NaOH. This derivative has a molar absorption coefficient of 8330 (at absorption maximum, 244 nm) and its absorbance follows a linear relationship with the concentration of bronopol within the range 5-25 micrograms ml-1. It has been validated that the spectrophotometric method can be applied successfully to the analysis of bronopol in raw material. The sensitivity of the method towards bronopol degradation in aqueous solution is comparable to that obtained by gas-liquid chromatography and enzymatic assays described elsewhere. Thus the proposed method is suitable for use in the study of the kinetics of bronopol degradation. A simple and sensitive detection of bronopol and bromonitroethanol (down to 2 micrograms) on a silica gel 60 F254 precoated thin layer chromatography plate based on the formation of the chromophoric derivative in the presence of ammonia vapour has been described.

Anti-Infective Agents↗
PubMed1995

Glyoxalase III from Escherichia coli: a single novel enzyme for the conversion of methylglyoxal into D-lactate without reduced glutathione.

A single novel enzyme, glyoxalase III, which catalyses the conversion of methylglyoxal into D-lactate without involvement of GSH, has been detected in and purified from Escherichia coli. Of several carbonyl compounds tested, only the alpha-ketoaldehydes methylglyoxal and phenylglyoxal were found to be substrates for this enzyme. Glyoxalase III is active over a wide range of pH with no sharp pH optimum. In its native form it has an M(r) of 82000 +/- 2000, and it is composed of two subunits of equal M(r). Glutathione analogues, which are inhibitors of glyoxalase I, do not inhibit glyoxalase III. Glyoxalase III is found to be sensitive to thiol-blocking reagents. The p-hydroxymercuribenzoate-inactivated enzyme could be almost completely re-activated by dithiothreitol and other thiol-group-containing compounds, indicating the possible involvement of thiol group(s) at or near the active site of the enzyme.

Aldehyde Oxidoreductases↗
PubMed1989

Methylglyoxal-catabolizing enzymes of Leishmania donovani promastigotes.

Methylglyoxal is a toxic metabolite with growth inhibitory properties against Leishmania donovani promastigotes. We have shown in the present study that both log and stationary phase promastigotes of L. donovani can catabolize methylglyoxal to D-lactate as the major end product. The specific activity of methylglyoxal reductase was found to be the highest of all the catabolic enzymes. In contrast, the anabolic pathway for methylglyoxal could not be detected. Moreover, when control promastigotes or promastigotes in which the glycolytic pathway was inhibited were incubated with glucose, glycerol or dihydroxyacetone phosphate as energy source, neither methylglyoxal nor D-lactate could be detected.

Alcohol Oxidoreductases↗
PubMed1989

Effect of heat-shock & nutritional stress on the expression of a neutral thiol protease in Leishmania donovani promastigotes.

The soluble intracellular protease was partially purified from L. donovani promastigotes. The activity of this enzyme increased with increase in temperature from 25 degrees C to 37 degrees C and was active optimally at 70 degrees C. This protease activity appeared to be decreased due to heat-shock of the promastigotes for 4 h at 37 degrees C and increased due to nutrient starvation. Inhibition of the protease by p-chloromercuribenzoate and iodoacetamide suggested that this enzyme could be a thiol protease.

Animals↗
PubMed1985

Purification and partial characterization of an exocellular proteinase from Trichophyton rubrum.

An exocellular proteinase produced by Trichophyton rubrum in a glucose-peptone broth was purified from lyophilized and dialysed culture filtrate of the dermatophyte by Sephadex G-100 gel filtration and preparative polyacrylamide gel electrophoresis. The purified enzyme was a homogeneous protein of molecular weight 34700 and it could hydrolyse azoalbumin, casein, bovine serum albumin, alpha-N-benzoyl-L-arginine ethyl ester and p-toluenesulfonyl-L-arginine methyl ester but not N-benzoyl-L-tyrosine ethyl ester, alpha-N-benzoyl-DL-arginine-p-nitroanilide and keratin. The enzyme showed an alkaline pH optimum and was not activated by divalent metal ions but inhibited strongly by phenylmethylsulfonylfluoride. Thus the enzyme was identified as an alkaline serine proteinase.

Chromatography, Gel↗
PubMed1983

Effect of undecanoic acid on lipid composition of Trichophyton rubrum.

Phospholipid and neutral lipid composition of undecanoic acid (UDA) resistant mutant of Trichophyton rubrum were compared with those of the UDA sensitive parent strain of this dermatophyte. When grown in glucose-peptone broth under identical conditions, contents of neutral and phospholipids in UDA resistant mutant were nearly double of those in the UDA sensitive parent strain. Glyceride, sterol, sterol ester and phospholipid contents of mycelium increased when UDA sensitive strain was grown in presence of low concentration of UDA, sufficient to cause partial growth inhibition of this strain. UDA in growth medium did not change the lipid composition of the UDA resistant mutant.

Drug Resistance, Microbial↗
PubMed1983

Urease activity in Trichophyton mentagrophytes.

Urease activity was detected in the dermatophyte Trichophyton mentagrophytes cells at early exponential phase of growth. Specific activity of urease decreased with culture age. At exogenous urea concentrations above 2 mM formation of urease was inhibited. The pH optimum lay at 7-7.5, the Km being 14 mM. No urease activity could be detected in cell-free culture fluid of T. mentagrophytes. No endo- or exocellular urease activity could be detected in a T. rubrum strain grown with or without urea.

Ammonia↗
PubMed1982

Effect of undecanoic acid on the production of exocellular lipolytic and keratinolytic enzymes by undecanoic acid-sensitive and -resistant strains of Trichophyton rubrum.

Effects of undecanoic acid on exocellular lipase, phospholipase A and keratinase activities of wild type undecanoic acid-sensitive (udas) and an undecanoic acid-resistant mutant (udar) of Trichophyton rubrum (derived from the udas strain) were determined. Undecanoic acid inhibited the production of exocellular lipase and keratinase but stimulated the production of exocellular phospholipase A in T. rubrum udas. Undecanoic acid did not affect exocellular lipase production by T. rubrum udar. Lipase production by the udar mutant was lower than that of the udas parent. No exocellular keratinase could be detected in the udar strain which had very low capacity for invasion of keratinized tissue.

Drug Resistance, Microbial↗
PubMed1982

Effect of undecanoic acid on phospholipid metabolism in Trichophyton rubrum.

At its minimum inhibitory concentration, undecanoic acid (UDA) inhibits biosynthesis of phosphatidyl serine, phosphatidyl ethanolamine and polyphosphoinositol but does not inhibit the synthesis of phosphatidyl glycerol, phosphatidyl choline, phosphatidyl inositol and phosphatidic acid in Trichophyton rubrum. At higher concentration, however UDA inhibits biosynthesis of all phosphatides present in this dermatophyte. UDA also affects catabolism of these phosphatides. This inhibitory effect of UDA may be partially responsible for its toxic action on T. rubrum.

Fatty Acids↗