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Biomedical subjects

C F Curtis

Publications and source records attributed to C F Curtis.

At least 145 records · Page 8Linked to original sources
PubMed1981

Field measurement of the effective dominance of an insecticide resistance in anopheline mosquitos.

Anopheles culicifacies that were susceptible, heterozygous, or homozygous resistant to HCH and dieldrin were differentially marked with fluorescent dusts and released twice weekly into village huts in Pakistan that had been sprayed with four different dosages of HCH to see which of the genotypes died and which survived. The three highest dosages killed all three genotypes in the first four weeks, and heterozygotes and susceptibles for at least 12 weeks. The lowest dosage killed all the susceptibles throughout the period, and all but 0.07% of the heterzygotes. Thus the resistance is effectively recessive at the higher dosages and unlikely to be selected rapidly, as long as the gene frequency is low to start with and the houses are sprayed regularly. Similar releases of partially and completely resistant A. stephensi, and completely resistant A. subpictus, showed greater survival rates on exposure to the high HCH dosages than the same genotypes of A. culicifacies.

Animals↗
PubMed1980

A genetic study of the susceptibility of Anopheles gambiae to Plasmodium berghei.

In a study of the genetics of susceptibility and refractoriness of Anopheles gambiae to Plasmodium species, nine generations of selection resulted in a completely susceptible line and an entirely refractory line to Plasmodium berghei (a rodent malaria). The F1 progeny from reciprocal crosses between the lines differed in their susceptibility to the parasite. Backcrosses to the parent did not produce proportions of susceptible and refractory individuals consistent with single gene inheritance or with cytoplasmic inheritance but the influence of a sex linked factor was demonstrated.

Animals↗
PubMed1980

The susceptibility of Liberian Culex quinquefasciatus to Wuchereria bancrofti in Sri Lanka.

Strains of Culex quinquefasciatus collected in Liberia showed low susceptibility to Wuchereria bancrofti from Liberian donors. However, when the same mosquito strains were fed on W. bancrofti donors from Sri Lanka they showed equally high susceptibility as Sri Lankan C. quinquefasciatus simultaneously fed on the same donors. A Liberian strain did not respond to selection for refractoriness. Thus the strains of W. bancrofti from Liberia and Sri Lanka differ in their ability to infect specific mosquito strains and it is concluded that Liberian C. quinquefasciatus could not provide genes for use in the construction of a refractory strain intended for the replacement of Sri Lankan vector populations.

Animals↗
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↗
PubMed1976

A new sex-linked mutant short wing in Aedes aegypti.

A spontaneous recessive sex-linked mutant short wing has been discovered in the mosquito Aedes aegypti. It is situated less than one cross-over unit from the sex determining locus. In homozygous females, flight is impaired and the survival and fecundity is markedly subnormal. Two possible uses of this gene for genetic control operations are envisaged: (a) to provide automatic sexing of males for release and (b) enhancement of the population control potential of other available genetics systems.

Aedes↗
PubMed1976

Comparative field cage tests of the population suppressing efficiency of three genetic control systems for Aedes Aegypti.

Cycling populations of Aedes aegypti were set up in cages and managed in such a way that the populations had a maximum of threefold recovery potential in response to control measures. Into three such populations daily releases were made of males which had been chemosterilised, or were double translocation heterozygotes (T1T3) or T1T3 with sex ration distortion (DT1T3). Eradication of the populations was achieved with all cases, but the rate of suppression was markedly slower with T1T3 than the other two systems, with which the rates were similar. T1T3 and DT1T3 releases introduced considerable inherited genetic loads into the target populations. The results were in general agreement with computer predictions.

Aedes↗
PubMed1976

Partial loss of cytoplasmic incompatibility with age in males of Culex fatigans.

The cytoplasms of Paris and Delhi strains of Culex fatigans have been reported to be bi-directionally incompatible. However, in the present study it is shown that with increasing age males with Paris cytoplasm show an increasing degree of partial compatibility with Delhi females. A male history of previous mating seems a contributory effect in enhancing the degree of partial compatibility. The relevance of partial compatibility to genetic control of C. fatigans is discussed.

Aging↗
PubMed1976

Population replacement in Culex fatigans by means of cytoplasmic incompatibility. 2. Field cage experiments with overlapping generations.

Three experiments were carried out in field cages to test the principle of "transport" of a desirable gene or chromosome into a wild Culex fatigans population as a result of the sterility in cross-matings associated with cytoplasmic incompatibility. Cycling populations of Delhi origin were established in the cages and daily releases were made of the IS31B strain, which has Paris cytoplasm and carries a male-linked translocation. It was shown that, if sufficient releases were made to establish a majority of the Paris cytoplasmic type, complete replacement by this cytoplasmic type subsequently occurred. However, as a result of partial compatibility of males of the Delhi population with Paris females, "recombinant" males with Paris cytoplasm and no translocation were produced. In an experiment in which a continuous low rate of "immigration" of a strain of Delhi origin was simulated, a gradual increase of the Paris cytoplasm nontranslocated type occurred, and renewed IS31B releases were necessary after 5 months to restore the predominance of this type. The results are compared with computer predictions and discussed in relation to the transport of genes for filaria refractoriness or chromosome translocations into wild populations.

Animals↗