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S Adhya

Publications and source records attributed to S Adhya.

138 records · Page 8Linked to original sources
PubMed1973

In vitro repression of the transcription of gas operon by purified gal repressor.

We have studied the in vitro repression of gal mRNA synthesis by the gal repressor from Escherichia coli. By use of a four-step purification procedure involving chromatography on phosphocellulose, DEAE-cellulose, and an affinity resin, the gal repressor has been purified about 1600-fold from a crude cell extract. The purification was aided by use of a cell extract made after prophage induction of cells lysogenic for bacteriophage lambda that carries the gal repressor gene (galR). The highly purified gal repressor is an effective and specific repressor of in vitro synthesis of gal mRNA with lambda gal DNA as template. Both D-fucose and D-galactose overcome the action of gal repressor; the half-maximal concentrations of D-fucose and D-galactose for overcoming the action of repressor are 1 mM and 0.5 mM, respectively. The repressor fails to repress gal-specific transcription when the gal DNA contains a cis-dominant operator constitutive (O(c)) mutation. We conclude that the gal repressor recognizes the gal operator site and acts by preventing gal transcription.

Ammonium Sulfate↗
PubMed1971

Phosphoglucomutase mutants of Escherichia coli K-12.

Bacteria with strongly depressed phosphoglucomutase (EC 2.7.5.1) activity are found among the mutants of Escherichia coli which, when grown on maltose, accumulate sufficient amylose to be detectable by iodine staining. These pgm mutants grow poorly on galactose but also accumulate amylose on this carbon source. Growth on lactose does not produce high amylose but, instead, results in the induction of the enzymes of maltose metabolism, presumably by accumulation of maltose. These facts suggest that the catabolism of glucose-1-phosphate is strongly depressed in pgm mutants, although not completely abolished. Anabolism of glucose-1-phosphate is also strongly depressed, since amino acid- or glucose-grown pgm mutants are sensitive to phage C21, indicating a deficiency in the biosynthesis of uridine diphosphoglucose or uridine diphosphogalactose, or both. All pgm mutations isolated map at about 16 min on the genetic map, between purE and the gal operon.

Bacteriological Techniques↗
PubMed1966

Glucose effect and the galactose enzymes of Escherichia coli: correlation between glucose inhibition of induction and inducer transport.

Adhya, Sankar (University of Wisconsin, Madison), and Harrison Echols. Glucose effect and the galactose enzymes of Escherichia coli: correlation between glucose inhibition of induction and inducer transport. J. Bacteriol. 92:601-608. 1966.-The inhibitory effect of glucose on the induction of the enzymes required for galactose utilization ("glucose effect") was studied in Escherichia coli. Experiments on the uptake into the cell of labeled inducers (d-galactose-C(14) and d-fucose-H(3)) pointed to inhibition at the level of inducer transport as the possible primary mechanism of the glucose effect in the case of the gal enzymes. This interpretation was supported by the finding that a mutant constitutive for the lac enzymes was resistant to glucose inhibition of galactose induction of the gal enzymes; the mutant had acquired a glucose-resistant alternative transport mechanism for galactose via the constitutively synthesized galactoside permease. Further support for the transport inhibition model was provided by the finding that glucose did not substantially inhibit induction of the gal enzymes when glucose and galactose were produced intracellularly by beta-galactosidase hydrolysis of lactose, even if excess glucose was added. The inducer uptake experiments also showed that d-galactose and d-fucose probably enter the cell via different transport systems, although uptake of both compounds was inhibited by glucose.

Carbon Isotopes↗
PubMedDate not supplied

Toxoplasmosis in women of child bearing age and infant follow up after in-utero treatment.

A total of 540 women (including 70 pregnant cases) of child bearing age with bad obstetrical history were tested serologically for anti-toxoplasma antibody using microlatex agglutination test. Forty two women including 5 cases of pregnancy were found to be seropositive in a titre of 1:32 or more. Maximum prevalence (10.2%) and highest titer of anti-toxoplasma antibodies were observed in women of 35-42 years age group. The overall prevalence of toxoplasmosis in these women was 7.7%, whereas it was 7.1% in pregnant women. Further studies are needed to estimate the exact rate of prevalence of infection. Of the 70 pregnant women, 5 were seropositive and two of them acquired infection during pregnancy which was detected by IgM immunosorbent assay. Seropositive pregnant women were treated using combined regimen of sulfadiazine and pyrimethamine. Four infected women with pregnancy were followed up and one did not turn up subsequently. There was spontaneous abortion in one case and in 3 other cases full term normal babies were delivered. Incidence of toxoplasmosis in women is low because of infrequent and uncommon practices of ingesting undercooked or uncooked food stuff specially meat by a substantial number of the population surveyed.

Adolescent↗
PubMedDate not supplied

Neonatal candidemia.

Fifty five clinically diagnosed cases of neonatal septicaemia of the nursery ward, Medical College Hospital Calcutta were subjected to blood culture on two consecutive days in all cases. Bacterial isolates were found in 34 (61.8%) cases as pure growth and candida species from 9 (16.4%) as pure culture. Remaining 12 samples did not yield any growth. Species distribution of candida showed C. albicans 6, C. parapsilosis 2, and C. guillermondii 1. Asphyxia neonatorum was the common feature in all cases of candidaemia. All neonates with candidal infection were low-birth-weight and premature. C. albicans, the predominant species (66.6%) recovered, was responsible for a localised outbreak of infection in the nursery.

Candidiasis↗
PubMedDate not supplied

Outbreak of neonatal septicemia with multidrug resistant Klebsiella pneumoniae.

A nosocomial outbreak of neonatal septicemia due to K. pneumoniae occurred in nursery during June-July, 1991. Klebsiella pneumoniae (Klebocin type 314) was recovered from blood of 33 (70.2%) of 47 neonates with septicemia. Multiple drug resistance was observed in all the cases. The same strain of K. pneumoniae was recovered from the neonates and environment of nursery and labour room as well. The outbreak was attributable to environmental dissemination.

Cross Infection↗
PubMedDate not supplied

Detection of Leishmania in the blood of early kala-azar patients with the aid of the polymerase chain reaction.

Samples from 39 patients with symptoms suggestive of early visceral leishmaniasis were independently assayed by microscopy of tissue smears, enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) of blood deoxyribonucleic acid. Of these patients, 19 were confirmed as positive or negative by all 3 tests; 11 patients (28%) negative by smear were positive by ELISA and PCR; and 7 (18%) were positive by PCR alone. These results demonstrate the high sensitivity of the non-invasive PCR and, to a smaller extent, ELISA, in the early diagnosis of visceral leishmaniasis.

Animals↗
PubMedDate not supplied

Systems for generating and detecting mutations in the galactose operon promoter region.

We discuss the use of plasmid systems which enable us to generate and detect mutations in the Escherichia coli galactose operon promoter region. We describe the isolation of mutants which map the galactose promoters and which pinpoint the sites for the binding of the cyclic AMP-binding protein (CRP) and the galactose repressor. Finally, we describe how such mutations can be transferred from the plasmid systems to the intact galactose operon on the host chromosome.

Bacterial Proteins↗