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Biomedical subjects

S Sharma

Publications and source records attributed to S Sharma.

At least 1,369 records · Page 76Linked to original sources
PubMed1981

Cloning of the uvrC gene of Escherichia coli: expression of a DNA repair gene.

We have cloned the uvrC gene of Escherichia coli, using an F' plasmid carrying the uvrC region as a source of DNA. Two plasmids, pSC101 and pBR322, were used as cloning vectors. The recombinant plasmids were selected for their ability to complement the uvrC defect of E. coli strains AB1884 and N177. We conclude that the uvrC structural gene is contained in a 1.9-kilobase DNA fragment. The protein encoded by the uvrC gene appears to have a monomer molecular weight of 64,500 as analyzed by denaturing polyacrylamide gel electrophoresis. Strains containing multicopy uvrC+ plasmids overproduce a factor that is missing in lysates of uvrC- mutants and required for an in vitro model repair reaction. The expression of uvrC+ hybrid plasmids suggests that the structural gene is separated by at least 0.8 kilobase from the regulatory region.

DNA Repair↗
PubMed1981

BCG induced immunity to Mycobacterium leprae in mice.

One to three BCG vaccinations were given to various groups of mice--25 to 2 days preceding challenge with Myco. leprae. Harvesting of Myco. leprae was done every month upto a period of 7 months. Lymph node enlargement was taken as an indicator of successful vaccination. An increasing degree of protection was noted in BCG immunised mice as observed by a reduced number of bacilli harvested. Protection afforded was proportional to the number of doses of BCG given.

Animals↗
PubMed1981

Myco. leprae infection in normal, thymectomised irradiated and thymus transplanted mice.

Normal mice and thymectomised, X-irradiated and thymic transplanted groups of mice were challenged with 10(3) Myco. leprae in the foot pad. Course of infection was studied for a period of seven months by sacrificing animals every month and counting the bacilli from the pooled tissues. In the thymectomised irradiated group the counts showed a plateau from 5th month onwards, whereas in control and thymus implant group the counts rose in 6th and 7th months.

Animals↗
PubMed1980

DNA polymerase III-dependent repair synthesis in response to bleomycin in toluene-treated Escherichia coli.

Bleomycin (BLM) is an antitumor drug which interacts with and damages DNA. We have reported a repair response dependent on DNA polymerase I in toluene-treated Escherichia coli. We report here that DNA polymerase III can also catalyze a repair response in toluene-treated E. coli following exposure to BLM. Polymerase III-mediated synthesis differs because it is ATP-dependent, whereas polymerase I-mediated repair synthesis is not. Polymerase III repair synthesis is independent of replicative synthesis, as demonstrated in a polA-, dnaBts strain, or use of Novobiocin to inhibit replication, and replication persists in the presence of repair synthesis. It appears that ATP-dependent repair synthesis in response to BLM is also present in polA+ strains. Repair synthesis does not require the uvrA gene product.

Bleomycin↗
PubMed1980

Personality structure and adjustment pattern in bronchial asthma.

A controlled study was conducted on 25 bronchial asthma patients in order to understand their personality structure, interpersonal relationships, conflicts and adjustment patterns. Psychometric evaluation was done by administering Rorschach's test, Eysenck's rating scale for anxiety and neurasthenic tendency, and sentence completion test. The results revealed that the asthmatics were intelligent but inhibited. They had covert aggression, neurotic constriction and marked affectional and dependency needs. They had considerable anxiety and were unable to use their energy for constructive work. Excessive dependency on the mother and sexual disturbance were prominently noticeable. They were possessed with irrational fears, guilt feelings and insecurity. Though high goals were set they were unable to achieve them. The present data suggest avenues for further research in the cross-cultural field.

Adolescent↗
PubMed1980

Some circulating factors which influence granulocyte-monocyte production in the chick with myeloblastic leukemia.

Soft-agar cloning was used to investigate possible granulopoietic-monopoietic regulatory defects in the chick with myeloblastic leukemia induced by avian myeloblastosis virus. The plasma levels of granulocyte-monocyte colony-stimulating activity (CSA) of normal and leukemic plasmas were the same when undiluted or unfractionated plasmas were tested. However, dilution or fractionation revealed elevations in plasma CSA levels in the leukemic animals. Most of the activity in both normal and leukemic plasma eluted in the void-volume peak during Sephadex G-200 gel filtration, and the CSA levels in the leukemic peak were increased 5- to 10-fold. This increase did not reflect higher levels of an inhibitory lipoprotein eluting in the void volume since the differential between normal and leukemic plasma was present after delipidation. We therefore investigated the possibility that a nonlipoprotein inhibitor was present. Sephadex G-200 chromatography of leukemic plasma revealed that a potent inhibitor of colony formation was present in one of the peaks of material eluting from the column. Eight micrograms of this material inhibited colony formation by 50%. This inhibitory material was not detected in corresponding fractions obtained after chromatography of normal plasma. These data show that plasma from the chick with myeloblastic leukemia has marked elevated levels of CSA and that it also contains an inhibitor of colony formation which is absent or present at very low levels in normal plasma. Finally, leukemic plasma contained abundant amounts of avian myeloblastosis virus polypeptides which are being investigated for possible relationships to the above-described activities.

Animals↗