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S K Subbarao

Publications and source records attributed to S K Subbarao.

67 records · Page 4Linked to original sources
PubMed1977

Segregation of cytoplasmic incompatibility properties in Culex pipiens fatigans.

Maternally inherited variants, which arose within a laboratory colony of Culex pipiens fatigans, have been studied by rearing cultures from single egg rafts. Segregation, i.e, variation of cytoplasmic incompatibility properties between the male progeny of individual females, was demonstrated. Also, from the daughters of individual females, sub-lines were derived within which all the males showed the same incompatibility or compatibility properties. Among the descendants of tetracycline-treated individuals were lines which superficially simulated these phenomena, but theses lines ultimately reverted to the cytoplasmic compatibility type of the strain which was submitted to the treatment. The types of variation s in cytoplasmic incompatibility properties that have been studied are discussed.

Animals↗
PubMedDate not supplied

Plasmodium vivax: enzyme polymorphism in isolates of Indian origin.

185 isolates of Plasmodium vivax were collected from patients visiting the malaria clinic run by the National Malaria Eradication Programme, Delhi, India. Percoll gradient centrifugation was used to concentrate P. vivax parasites from 0.4 to 0.5 ml of blood collected by finger prick. The parasite concentrate from each isolate was electrophoretically analysed for lactate dehydrogenase (LDH), NADP-dependent glutamate dehydrogenase (GDH), glucose phosphate isomerase (GPI) and adenosine deaminase (ADA). Variations were observed in GPI, GDH and ADA systems. Four electrophoretic forms of GPI and 5 each of GDH and ADA were observed. Electrophoretic mobilities of the different isoenzymic forms in P. vivax were identical to those reported for P. falciparum, indicating that the 2 species cannot be differentiated on the basis of electrophoretic patterns of the 4 enzyme systems studied.

Adenosine Deaminase↗
PubMedDate not supplied

Genetic structure of Plasmodium vivax isolates in India.

Variations in the allelic composition of glucose phosphate isomerase (GPI), NADP-dependent glutamate dehydrogenase (GDH) and adenosine deaminase (ADA) enzyme systems of Plasmodium vivax were observed in isolates of Indian origin in 1985-1993. No significant difference was observed in allelic frequencies in different years. The data indicated random distribution of GPI, GDH and ADA alleles among the isolates, suggesting that loci for these enzymes were not linked. A high proportion of the isolates comprised at least 2 genetically distinct clones, the mean number of clones per isolate being 1.4. There was no significant difference in the number of oocysts in Anopheles stephensi fed on uniclonal and multiclonal isolates. No difference was observed in the proportions of uniclonal and multiclonal isolates during low and high transmission periods.

Adenosine Deaminase↗
PubMedDate not supplied

X-linkage of malic enzyme in Anopheles culicifacies species B.

A survey for malic enzyme (Me) in laboratory strains of species A and species B of Anopheles culicifacies had uncovered two electrophoretic variants, slow and fast, in two strains of species B. Genetic analysis revealed the two variants to be codominant alleles segregating at a locus, Me, which is sex linked. Because of the XX-XY sex determining mechanism, in F1 females, two electromorphs, viz., slow and fast, were observed, whereas in males only one electromorph of maternal origin was seen. Linkage experiments with another X-linked mutant, white eye (w), indicated the map distance between the two loci to be 9.52 +/- 0.86.

Animals↗
PubMedDate not supplied

Dynamics of malaria transmission under changing ecological scenario in and around Nanak Matta Dam, Uttaranchal, India.

To understand the transmission dynamics of malaria in three different ecotypes, namely watershed (forest), seepage (Nanak Matta Dam) and plain (non-forest, non-dam) areas of Nainital and Udham Singh Nagar districts of Uttaranchal, entomological and parasitological investigations were carried out from July 1996 to June 1997. In the three ecotypes, average per man hour densities of adult vector species in human dwellings and cattlesheds recorded were high for Anopheles culicifacies from April to September and October to March for An. fluviatilis. Prevalence of both An. culicifacies and An. fluviatilis was higher in the forest area as compared to other two areas. Observations on gonotrophic condition revealed endophilic tendency of both vector species. Higher number of both vector species were found in outdoor than indoor during night human bait collections. Out of 864 specimens of An. fluviatilis dissected, one showed natural infection of sporozoites in salivary glands in the month of November from the forest area only. Sibling species study of An. fluviatilis revealed the presence of species S for the first time in the forest area. Parasitological investigations also depicted high incidence of malaria in the forest area as compared to other two areas. Overall results from the study indicated active malaria transmission in the forest area.

Adult↗
PubMedDate not supplied

Ahaptoglobinemia (HpO) and malaria in India.

Haptoglobin (Hp) polymorphism analysed among P. vivax and P. falciparum patients and malaria negative subjects from areas with different epidemiological situations had shown high incidence of ahaptoglobinemia (HpO) among malaria patients. A definite association of HpO with P. vivax as well as P. falciparum malaria in Indian subjects had been observed. However, low sensitivity and reliability of HpO index indicates that it can not be a good indicator for determination of malaria endemicity. About 75 per cent of HpO subjects with P. vivax infection when treated with chloroquine showed typable Hp polymorphs by 8-9 days of post-treatment.

Haptoglobins↗