Homozygous chromosomal aberrations in Anopheles stephensi

Homozygotes for six autosomal paracentric inversions, an inserted paracentric inversion, an autosomal translocation, and two X-chromosome-chromosome 3 translocations in Anopheles stephensi are described. Three of these aberrations are being maintained in pure strains without the necessity of selection.

Inversion polymorphisms in natural populations of Anopheles stephensi

A preliminary survey of natural populations of Anopheles stephensi Liston in Pakistan has uncovered the presence of 16 autosomal paracentric inversions. Twelve previously undescribed inversions were observed in the field populations and an additional new one was seen in a laboratory colony. A comparison of urban and rural populations showed striking differences in the kinds and frequencies of paracentric inversions.

Vector incrimination studies and observations on species A and B of the taxon Anopheles culicifacies in Pakistan

Studies on anopheline mosquitoes in selected villages of Punjab Province, Pakistan have incriminated Anopheles culicifacies species A as the primary malaria vector. Although An. stephensi and An. subpictus showed higher immediate gut infection rates, estimations of relative abundance, age structure and survivorship, and observations of late gut and salivary gland infection rates suggested that neither species was a major vector in these villages. A survey of An. culicifacies populations detected the presence of both species A and B in several localities in Pakistan. Laboratory investigations demonstrated that both species are capable of supporting the extrinsic cycle of Plasmodium vivax. No recombination was observed between X-linked loci in species A/species B hybrid females; however, recombination was observed between loci in chromosome 2. Allelic tests between the X-linked white eye locus in species A and an X-linked white eye mutant in species B showed that the two loci are not allelic.

Induced chromosomal aberrations and linkage group-chromosome correlation in Anopheles stephensi

Genetic and cytogenetic investigations of 14 strains of Anopheles stephensi with induced chromosomal aberrations have resulted in the assignment of the three linkage groups to their respective chromosomes. In addition, the correlation between the ovarian polytene chromosomes and the mitotic chromosomes was demonstrated. Indirect evidence for the presence of heterochromatic segments in the chromosomal complement was found.

Antibacterial action of quinolones on Escherichia coli. I. Structure/activity relationship

Quinolones, a large group of substituted heterocyclic compounds synthesized by ICI (U.K.), showed antibacterial activity both in vivo and in vitro studies. In the present work an attempt was made to evaluate their antibacterial activity in relation to their chemical structure. Active compounds possess carboxylic and nitroside groups. Regarding the pattern of growth inhibition quinolone with carboxylic side group showed a different behaviour than quinolone possessing nitro side group.

Anopheles culicifacies Giles: a release-recapture experiment with cohorts of known age with implications for malaria epidemiology and genetical control in Pakistan

A mark-release-recapture experiment with the progeny of wild collected Anopheles culicifacies was performed during the monsoon season of 1978 at the village of Khano-Harni, a malarious area situated in Lahore District, Punjab Province, Pakistan. The recapture rates of males and females released at breeding and resting sites were statistically comparable and totalled 8.0% for females and 5.9% for males collected resting in houses and cattle sheds. Mating occurred mostly on the night following the evening of release when the females were about two days old. Insemination rates for females released at resting and breeding sites were statistically comparable. The initial gonotrophic cycle required four days; subsequent cycles occurred at two-day intervals with re-feeding on the same night as oviposition. Constant daily survivorship estimated from the decline in recaptures per day was 0.568 for females and 0.676 for males. Female survivorship estimated by vertical age grading methods ranged from 0.472 to 0.820. Horizontal life tables were calculated from the decline in recaptures and from vertical age-grading techniques and indicated that female or male life expectancy at emergence was less than 2.5 days. Population size was calculated using the Lincoln Index, Jackson's positive and negative methods and Itô's modification of Jackson's positive method and averaged from 1045.5 to 1049.6 females and from 449.1 to 1323.7 males. The relationship of these results to malaria transmission and genetical control is discussed.