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S K Poddar

Publications and source records attributed to S K Poddar.

27 records · Page 2Linked to original sources
PubMed1987

Central nervous system infections in Benghazi, Libya: experience from a community-based adult medical neurology set-up.

During a 2-year period, a total of 43 incident cases of central nervous system infections occurred in the adult (aged 15 years and above) population in Benghazi, Libya. This comprised 17 patients with aseptic meningitis, 10 acute bacterial meningitis, four tuberculous meningitis, five encephalitis, four neurosyphilis, two hydatidosis and one bilharzial myelopathy. The aetiology of the aseptic meningitis and encephalitis could not be established. The annual incidence rates of aseptic, septic and tuberculous meningitis, and encephalitis were 3.4, 2, 0.8 and 1 per 100,000 population, respectively.

Adolescent↗
PubMed1986

Chromosome analysis by two-dimensional fingerprinting.

A two-dimensional fingerprinting technique has been developed that allows large, cell genome-size DNA's to be analyzed by restriction endonuclease cleavage and separation of DNA fragments by agarose gel electrophoresis. Equations have been derived to determine the genome size and number of cleavage sites from analysis of the distribution of fragment lengths. Genome sizes of Escherichia coli strain JM101 and two strains of the mycoplasma Acholeplasma laidlawii measured by this method are in agreement with published values. Other uses of two-dimensional fingerprinting for studies of prokaryotic and eukaryotic genome structure and organization are described.

Acholeplasma laidlawii↗
PubMed1986

Type I topoisomerase activity after infection of enucleated, synchronized mouse L cells by vaccinia virus.

The time course of appearance of type I topoisomerase activity after the infection of mouse L cytoplasts by vaccinia virus was determined. When the enucleation procedure was carried out with unsynchronized cell cultures, a high level of host-cell-specific type I topoisomerase activity was found associated with the resulting cytoplasts. If cells were first synchronized by the two-cycle thymidine block method and then enucleated after release, the level of host type I topoisomerase activity was also high for S-phase-enucleated cells but was very low for cytoplasts prepared from cells previously synchronized and enucleated during either the G1 or the G2 phase. After the infection of G1-phase-enucleated cytoplasts with vaccinia virus, newly synthesized type I topoisomerase activity first appeared at about 3 h postinfection. Virosomes were isolated from the infected, synchronized cytoplasts and assayed for the presence of type I topoisomerase activity. The activity remained at the top of a sucrose gradient, well resolved from the virosome fraction, at the low salt levels (0.01 M KCl, 0.01 M Tris hydrochloride, pH 8.0) normally used in the course of virosome purification. If the sedimentation was at the higher salt concentration (0.15 M KCl) at which the enzyme shows optimal activity, type I topoisomerase cosedimented with the virosome fraction onto the sucrose gradient cushion. These results show that the type I topoisomerase activity dependent upon vaccinia virus infection may be detected with high sensitivity in G1-phase-enucleated cytoplasts. The association with virosomes is consistent with an involvement of topoisomerase activity either in DNA replication or in late transcription.

Animals↗
PubMed1985

Heterogeneous progeny viruses are produced by a budding enveloped phage.

Infection of Acholeplasma laidlawii cells by the temperate enveloped mycoplasma virus L2 results in production of three morphological forms of progeny L2 virus: L2-I, L2-II, and L2-III. These morphological forms can be separated by velocity sedimentation and agarose gel electrophoresis. The latter technique was used to size the quasi-spherical particles: L2-I is 74 nm, L2-II is 88 nm, and L2-III is 132 nm in diameter. The protein composition of the three L2 forms is the same, although there are differences in protein stoichiometric ratios. L2-I, L2-II, and L2-III have the same 11.8 kilobase pair superhelical DNA genome. However, UV inactivation studies and restriction frequency measurements indicate that L2-I and L2-III each contain 1 genome copy, while L2-II contains 2-3 genome copies.

Acholeplasma laidlawii↗
PubMed1984

Effect of novobiocin on mycoplasma virus L2 replication.

L2 is a temperate mycoplasma virus containing 11.8 kilobase pairs of negatively superhelical double-stranded DNA. We observed L2 DNA with less superhelicity in novobiocin-treated cells than that in untreated cells. However, although no change in viral DNA superhelicity could be found in novobiocin-treated novobiocin-resistant cells, L2 production decreased in these novobiocin-treated cells.

Acholeplasma laidlawii↗
PubMedDate not supplied

Detection and discrimination of B pertussis and B holmesii by real-time PCR targeting IS481 using a beacon probe and probe-target melting analysis.

A beacon probe was designed to detect one of the two documented single nucleotide changes in IS481 target allele of Bordetella holmesii genome as compared to Bordetella pertussis. PCR amplified product targeting a region of IS481 in presence of the probe was subjected to a post-PCR hybridization and melting cycle. Hybrid of the probe with B. pertussis specific target had a different thermal stability than that with allele having the single nucleotide change in B. holmesii. The melting of B. pertussis-probe hybrid occurred in a single phase; while that of B. holmesii-probe hybrid was biphasic-one for allele identical to that in B. pertussis and the other for that with a single nucleotide change in B. holmesii genome, with a difference in melting temperature (T(m)) of 6.5 degrees C. The characteristic melting profile and T(m) analysis was the basis for discriminatory detection of B. pertussis from B. holmesii. The method was applied in a representative set of clinical isolates of B. pertussis and B. holmesii and the result was in agreement with conventional culture method.

Bordetella↗