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Biomedical subjects

S Narang

Publications and source records attributed to S Narang.

At least 55 records · Page 3Linked to original sources
PubMed1982

Radiation induced reciprocal translocations and inversions in Anopheles albimanus.

Reciprocal translocations and inversions were induced in Anopheles albimanus Wiedemann by irradiation of males with X rays. A total of 1669 sperm were assayed, and 175 new aberrations were identified as follows: 102 reciprocal translocations (67 autosomal and 35 sex-linked), 45 pericentric inversions, and 28 paracentric inversions. Eleven of the translocations were nearly whole-arm interchanges, and these were selected for the construction of "capture systems" for compound chromosomes. Two double-heterozygous translocation strains and four homozygous translocation strains were established. Anopheles albimanus females were irradiated, and a pseudolinkage scheme involving mutant markers was employed to identify reciprocal translocations. The irradiation of females was very inefficient; only one translocation was recovered from 1080 ova tested.

Animals↗
PubMed1981

Isozymes of Culex p. fatigans. III. Genetics of leucine-amino-peptidase.

Zymograms of leucine-amino-peptidase (LAP) of the mosquito Culex pipiens fatigans Wiedemann (C. p. quinquefasciatus) showed 20 isozyme bands in the fourth instar larvae, 13 in the pupae and 3 in the older adults. Homozygous strains of Lap-1F (Fast) and Lap-1S (Slow) were isolated and linkage studies carried out. Lap-1F and Lap-1S allozymes act as codominant alleles, are sex linked and are located in linkage group I. The gene sequence is e-M-mar-Lap-1 (eye-gap, maroon-eye, leucine-amino-peptidase-1), and the linkage distances in the M-mar and mar-Lap-1 segments are 22.0 and 10.5, respectively. Gene frequency analysis of natural populations from Brazil and Pakistan showed the S allele was more frequent in the Brazilian populations whereas F was more frequent in the Pakistani populations. Fixation of F allele had occurred in two Pakistani populations.

Alleles↗
PubMed1979

Histochemical and electrophoretical studies in normal and infected Biomphalaria glabrata. II. Acid and alkaline phosphatase.

Various organs of normal and infected Biomphalaria glabrata were analysed, electrophoretically and histochemically, with respect to the acid phosphatase and alkaline phosphatase activity. In general, digestive gland, ovotestis and stomach show an increase in acid phosphatase activity in infected snails, whereas kidney and albumen gland show less activity. Alkaline phosphatase does not show any significant different in activity between normal and infected snails. Electrophoretically digestive glands of snails, twenty days after infection, show an extra faint band, whereas seven days after infection, the snails do not show any such extra band. Histochemically also after twenty days, infected snails show more activity in the sporocyst region, but those infected for only seven days, do not show any increase in acid phosphatase activity.

Acid Phosphatase↗
PubMed1979

[Genetics of anapheline populations. III. Electrophoretic analysis of Anopheles aquasalis (Diptera: Culicidae) (author's transl)].

Genetic variation at 26 loci in a natural population of Anopheles aquasalis has been studied by zymogram technique. Average proportion of polymorphic loci is 23% (criterion I) and 34% (criterion II). On the average 8.1% of the genome is in heterozygous condition in each individual. The degree of genetic variability varies from locus to locus. Some enzymes such as AO, alpha-GPDH, 3 loci of HK, 3 loci of LAP, 3 loci of MDH, GOT, 3 loci of ODH and one locus of EST (EST-4), are monomorphic. Of the rest, proportion of heterozygosity varies from the minimum of 0.041 at Xdh-2 to a maximum of 0.493 at Est-2. Similarly, except for the loci Est-2 and Est-3, proportion of heterozygote individuals is extremely low. A. aquasalis has a higher genetic identity with A. evansae (I = 0.625) than with A. argyritarsis (I = 0.543). There seems to be direct correlation between the genetic variability of a species and its capacity to explore diverse ecological nitches.

Animals↗
PubMed1978

Cloned seventeen-nucleotide-long synthetic lactose operator is biologically active.

A 17-nucleotide-long synthetic DNA molecule constituting the minimal recognition sequence of the lactose operator has been cloned in E. coli using the vehicle pBR313 and a synthetic HindIII adaptor. The clones containing the lac-pBR313 hybrid DNA constitutively produced beta-galactosidase. The level of beta-galactosidase was high and comparable to that obtained in cells carrying a 21-nucleotide-long synthetic lac operator on pMB9 plasmid or cells carrying a natural lac operator on pOP203-1 plasmid.

DNA↗
PubMed1978

Formation of asbestos bodies under the influence of parenteral iron overload.

The effect of parenteral administration of iron (dextran) on the number of asbestos fibers in the lungs, formation of asbestos bodies and the development of interstitial fibrosis was studied in guinea pigs exposed intratracheally to anthophyllite dust. The treatment did not accelerate, either qualitatively or quantitatively, the formation of asbestos bodies or retard the development of interstitial fibrosis. The number of naked asbestos fibers was also similar in anthophyllite-inoculated animals to those similarly inoculated, but having had, additionally, a previous saturation with iron.

Animals↗
PubMed1977

Dissolution of silicic acid from dusts of kaolin, mica and talc and its relation to their hemolytic activity. -- an in vitro study.

Hemolysis induced by native kaolin dust was found to run parallel to the amount of silicic acid dissolved from it. Native mica and talc dusts were hemolytic only to a small extent and the silicic acid dissolution from these dusts was also smaller in comparison to that of native kaolin. The proportionality between hemolysis and the amount of dissolved silicic acid was not consistently observed in the case of acid, alkali and water treated kaolin, mica and talc dusts.

Animals↗
PubMed1976

Alcohol dehydrogenase of Biomphalaria glabrata (Molusca: Pulmonata): polymorphism, genetic analysis, and interspecific variations.

Alcohol dehydrogenase of Biomphalaria glabrata has been characterized by electrophoresis, substrate specificities, and other physiochemical means. It exists as a multiple molecular form possessing a minimum number of three bands in ovotestis, five in digestive gland, and six in albumen gland. Each organ shows characteristic electrophoretic forms which differ in substrate specificities and the response to the organomercurial inhibitor p-hydroxymercuribenzoate. Mercaptoethanol treatment has no effect on any electrophoretic form. Genetic analyses of the electrophoretic variants show that three different loci are responsible for the synthesis of the various electrophoretic forms observed in this species. Different species vary in their electrophoretic patterns. A possible role of alcohol dehydrogenase isozymes in the phylogenetic relationship among three species, B. glabrata, B. tenagophila, and B. straminea, has been discussed.

Alcohol Oxidoreductases↗
PubMed1976

Glucose-6-phosphate dehydrogenase of Biomphalaria glabrata (Say , 1818) (Mollusca: Pulmonata). Characterization and inheritance pattern.

Glucose-6-phosphate dehydrogenase of Biomphalaria glabrata has been characterized by electrophoresis, kinetic properties and inheritance pattern. It exists as a single electrophoretic band with no polymorphism in the natural population studied during the present investigations. There are no organ-specific differences in electrophoretic pattern. The enzyme from the homogenates of various organs e.g., albumen gland, digestive gland, ovotestis and columellar muscle show similar physico-chemical parameters, such as optima for pH, NADP and glucose-6-phosphate. Incorporation of NADP is essential for maintaining the stability of the enzyme, failing which, there appear artifactual variations in electrophoretic mobility of the enzyme. The apparent lack of polymorphism in natural population of Biomphalaria glabrata has been discussed.

Animals↗
PubMed1976

Genetic variation in two natural populations of Biomphalaria tenagophila: esterases and alcohol dehydrogenase.

The polymorphism of two natural populations of snails, Biomphalaria tenagophila, from São José dos Campos, São Paulo State (SJ) and from Núcleo Bandeirante, Distrito Federal (BN), was studied with respect to esterase and alcohol dehydrogenase (ADH) zymograms. The two population zymograms do not differ qualitatively. However the high frequency of esterase a and b bands in SJ and of e,f and h in NB, is a diagnostic mark. Moreover, frequency of band e alone can be used to distinguish the two populations. The high frequency of 3-banded ADH phenotype is a diagnostic mark of the SJ population.

Alcohol Oxidoreductases↗
PubMed1975

Malate dehydrogenase of a mosquito, Culex p. quinquefasciatus: developmental changes, polymorphism, and physicochemical characterization.

Malate dehydrogenase (MDH) of larval, pupal, and adult stages of Culex p. quinquefasciatus has been characterized by electrophoresis, isoelectric focusing, and other physicochemical means. It exists as a multiple molecular form possessing a large number of isoenzymes, from a minimum of three in early instar larvae to as many as 14 in adults. The isoenzyme pattern changes during development with respect to both relative activity and the appearance of some new forms and disappearance of others. Each developmental stage possesses a characteristic electrophoretic and gel isoelectric focusing pattern. MDH isoenzymes differ in their response to heat and thiol reagents. Similar electrophoretic variants from larvae, pupae, and adults show great differences in their response to heat treatment at 50 C and 56 C, indicating some differentiation of isoenzymes in each stage of development. Homogenization of whole mosquitos in mercaptoethanol solution results in a sharp increase in the activity of the principal bands and a decrease or disappearance of minor ones. The possibility of some minor bands being "conformers" arising due to nongenetic factors is discussed.

Animals↗