PubMed Health⌕ Search

Biomedical subjects

T Bhowmik

Publications and source records attributed to T Bhowmik.

10 recordsLinked to original sources
PubMed1994

Cloning, characterization and insertional inactivation of the Lactobacillus helveticus D(-) lactate dehydrogenase gene.

A plasmid, designated pSUW100, encoding the D(-)lactate dehydrogenase [D(-)-LDH; NAD+ oxidoreductase, EC 1.1.1.28] from Lactobacillus helveticus CNRZ32 was identified from a genomic library by complementation of Escherichia coli FMJ39. The D(-)LDH gene was localized by Tn5 mutagenesis and subcloning to a 1.4-kb region of pSUW100. A 2-kb DraI fragment of pSUW100 encoding D(-)LDH activity was subcloned and its nucleotide sequence determined. Analysis of this sequence identified a putative 1,014-bp D(-)LDH open reading frame that encodes a polypeptide of 337 amino acid residues with a deduced molecular mass of 38 kDa. The distribution of homology to the CNRZ32 D(-)LDH gene in several lactic acid bacteria was determined by Southern hybridization using an internal fragment of the D(-)LDH gene as a probe. Hybridization was detected in leuconostocs and pediococci but not in lactococci or Lactobacillus casei. An integration plasmid was constructed from pSA3 and a 0.60-kb internal fragment of the D(-)LDH gene. This plasmid was used to construct a D(-)LDH-negative derivative of L. helveticus CNRZ 32 by gene disruption; this derivative was determined as producing only L(+)lactic acid. No significant difference in growth or total lactic acid production was observed between CNRZ32 and its D(-)LDH mutant.

Amino Acid Sequence↗
PubMed1994

Characterization of the Lactobacillus helveticus CNRZ32 pepC gene.

Sequence analysis of the aminopeptidase C gene (pepC) from Lactobacillus helveticus CNRZ32 identified a 1,332-nucleotide open reading frame coding for a polypeptide with motifs characteristic of cysteine proteinases. Homology to the pepC gene appears to be widely distributed among lactic acid bacteria.

Amino Acid Sequence↗
PubMed1993

Gene replacement in Lactobacillus helveticus.

An efficient method for gene replacement in Lactobacillus helveticus CNRZ32 was developed by utilizing pSA3 as an integration vector. This plasmid is stably maintained in CNRZ32 at 37 degrees C but is unstable at 45 degrees C. This method consisted of a two-step gene-targeting technique: (i) chromosomal integration of a plasmid carrying an internal deletion in the gene of interest via homologous recombination and (ii) excision of the vector and the wild-type gene via homologous recombination, resulting in gene replacement. By using this procedure, the chromosomal X-prolyl dipeptidyl aminopeptidase gene (pepXP) of CNRZ32 was successfully inactivated.

Chromosomes, Bacterial↗
PubMed1989

Simple Method To Detect beta-Galactosidase.

A simple and rapid method was developed to detect beta-galactosidase by using alpha- or beta-naphthyl-beta-d-galactopyranoside as substrate and fast garnet GBC as a dye coupler following polyacrylamide gel electrophoresis. This method was specific for beta-galactosidase but not for phospho-beta-galactosidase.

Journal Article↗
PubMed1988

Histological changes in the ovary and uterus of rat after injectable contraceptive therapy.

Histological changes were studied in the ovary and uterus of rats receiving different doses of Depo-Provera (DMPA) and Noristerat (NET-EN) for varying duration. The effect of DMPA on ovarian and uterine tissues was strongly progestational. The whole morphological alteration in the ovary after DMPA therapy appeared to be the atresia of the follicular apparatus with degeneration of the growing follicles. Uterine histology reflected that endometrial tissues gradually became inactive and with prolonged treatment at high doses, atrophy of the endometrium was noted. In NET-EN-treated rats, absence of mature follicles and recent corpora lutea reflected the blockade of ovulation. There was no extreme atrophy of the ovary or endometrium as found with DMPA treatment. With higher doses of NET-EN, endometrial growth was arrested.

Animals↗
PubMed1987

Selection of Lactobacillus acidophilus strains for use in "acidophilus products".

Recent studies by DNA-DNA hybridization revealed that strains now designated as L. acidophilus, can be divided into several groups and only one group should be classified as L. acidophilus. We studied several phenotypic characteristics in representative strains from the six DNA-homology groups of L. acidophilus. No group specific pattern was observed among the strains for fermentation of eight carbohydrates, growth at 15 and 45 degrees C, resistance to 0.2% oxgall, lysis by lysozyme or sensitivity to 17 antibiotics. However, some differences among groups were observed in beta-galactosidase (beta-gal) activity and surface layer (s-layer) protein. Strains in B1 do not have a s-layer or beta-gal while B2 strains also lack a s-layer but do possess beta-gal. All strains in groups A1, A2, A3 and A4, capable of growing in lactose, have beta-gal activity and also have a s-layer composed of protein subunits of different molecular weights (MW). Strains in A1 homology group have a s-layer with 46 Kd protein subunits while strains in other A groups have s-layer protein subunits that varied in MW within each group. On the basis of these two traits several isolates of unknown homology groups have been tentatively placed in A1, B1 or B2 groups. L. acidophilus from A1 group showed strain variation in beta-gal specific activity and rate of acid production and growth. For use in dietary adjuncts, L. acidophilus strains should be selected for these three and other desirable traits. They should be maintained and grown in media containing lactose.

Bacterial Outer Membrane Proteins↗
PubMed1987

Alterations in protein, sialic acid and some enzymes in cervical mucus of female rats during NET-EN treatment.

The effect of norethisterone enanthate (NET-EN) on cervical mucus protein, sialic acid and some enzymes (e.g. peroxidase, alkaline phosphatase and alpha-amylase) were studied in adult female rats. One mg NET-EN every 12 days was found to be an effective contraceptive dose of this drug in this species, acting primarily through the cervical mucus. NET-EN produced a highly significant increase in protein content and peroxidase and alkaline phosphatase activities. However, sialic acid content and amylase activity did not exhibit any definite pattern after NET-EN therapy. The increased protein content together with persistent elevated levels of peroxidase and alkaline phosphatase corroborates the hypothesis that NET-EN creates a progestogenic phase which prevents sperm penetration and thus conception.

Alkaline Phosphatase↗
PubMedDate not supplied

Alterations in blood sugar, protein, and lipid levels in Indian women by norethisterone enanthate.

Fasting levels of sugar, protein, and lipids, namely, cholesterol, triglyceride, and phospholipid, were determined in the blood of 150 women taking an injectable contraceptive, norethisterone enanthate, 200 mg every 60 days for 24 months. Triglyceride and cholesterol showed a statistically significant decrease from 10 and 16 months of use; however, both values returned to control level after use for 24 months. Serum phospholipids and total protein did not show significant changes, while the blood sugar level increased significantly from 12 months onwards and remained elevated (P less than .001) up to the end of the trial period.

Adolescent↗