PubMed Health⌕ Search

Biomedical subjects

T K Biswas

Publications and source records attributed to T K Biswas.

49 records · Page 3Linked to original sources
PubMed1986

Cationic form of beta-galactosidase in the germinating seeds of Vigna sinensis (Linn) Savi.

The cationic form of beta-galactosidase (EC 3.2.1.23) from the germinating seeds of Vigna sinensis has been separated from its other isoforms by DEAE-cellulose (DE-52) column chromatography and further purified by gel filtration and affinity chromatography. Polyacrylamide gel electrophoresis of the purified enzyme imparted a single protein band. The molecular mass of the enzyme as determined by Sephadex G-150 gel filtration is 58,800 Da. The optimum temperature and the optimum pH are 60 degrees C and 4.5, respectively. Most of the metal ions tested were inhibitory to the enzyme activity. The enzyme has Km for p-nitrophenyl beta-D-galactoside and o-nitrophenyl beta-D-galactoside of 0.56 and 2.0 mM, respectively. The Ki values of galactose and lactose are 2.4 and 70.0 mM, respectively. The energy of activation of PNPG for the enzyme is 10.3 kcal/mol.

Galactosidases↗
PubMed1986

A critical base in the yeast mitochondrial nonanucleotide promoter. Abolition of promoter activity by mutation at the -2 position.

The yeast mitochondrial promoter comprises a highly conserved nonanucleotide sequence, 5'-ATATAAGTA-3'. Transcription is initiated both in vivo and in vitro at the 3'-terminal A (+1). The G at the -2 position is strictly conserved. The requirement for this nucleotide is established by comparing the in vitro promoter activity of nonanucleotides containing any of the four bases at the -2 position, obtained as synthetic oligonucleotides. Only the synthetic promoter having G at the -2 position exhibits any promoter activity.

Base Sequence↗
PubMed1986

Nucleotides flanking the promoter sequence influence the transcription of the yeast mitochondrial gene coding for ATPase subunit 9.

The conserved nonanucleotide sequence functions as a promoter in the yeast (Saccharomyces cerevisiae) mitochondrial genome. A mitochondrial gene, Oli 1, which codes for ATPase subunit 9, has two identical nonanucleotide promoter sequences separated by 78 nucleotides, but they initiate transcription with very different efficiencies in vivo and in vitro. Deletion analysis has revealed that the nucleotide at position +2 of the weak downstream promoter accounts for its poor in vitro transcriptional activity. This finding was confirmed with site-specific mutations at +2 and +3 positions of a consensus synthetic promoter. The nonanucleotide mitochondrial promoter with a pyrimidine at position +2 acts as a weak promoter, whereas the same sequence with a purine at the +2 position functions as a strong promoter. The nucleotide at the +3 position further contributes to the relative promoter strength. These results suggest not only that the conserved nine-nucleotide sequence is required for the correct transcriptional initiation but also that other neighboring nucleotides influence the efficiency of promoter function.

Base Sequence↗
PubMed1985

Characterization of a yeast mitochondrial promoter by deletion mutagenesis.

We have generated collections of mutants of the promoter for the small rRNA gene from the mitochondria of yeast deleted from either the 3' or 5' end. Plasmids containing the partially deleted promoter were assayed for their ability to direct correct transcriptional initiation in a homologous in vitro system. We find that the region required for high-efficiency promoter function lies between positions -10 and +2. Our methods detected no effect of flanking sequences on the strength of this promoter.

Base Sequence↗
PubMed1985

Alkaptonuria.

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

A randomised multicentre study to compare the safety and efficacy of albendazole and metronidazole in the treatment of giardiasis in children.

A randomised control multicentre study to compare the safety and efficacy of albendazole and metronidazole in the treatment of giardiasis in children is reported. One hundred and fifty children of either sex (age range: 2-10 years) were randomised to receive either a single dose of 400 mg of albendazole suspension, or 22.5 mg/kg/day of metronidazole in 3 divided doses for 5 consecutive days. At the end of therapy, majority of children in both treatment groups were symptom free. Two days after completion of therapy, 97% of children in both treatment groups were giardia free in the stools. Side effects were noted in 3 children in the albendazole group, and in 20 children in the metronidazole group. We conclude that albendazole suspension is as effective as metronidazole in the treatment of giardial infection in children. It is safe and has fewer side effects as compared to metronidazole.

Albendazole↗