Morphological and cytochemical characterization of female Anopheles albimanus (Diptera: Culicidae) hemocytes.

Hemocytes of 2- to 3-d-old female Anopheles albimanus Wiedemann are described by morphology, cytochemistry, and functional criteria. Supplemented Grace's insect medium in a modified Foley's perfusion method was used to obtain hemolymph from An. albimanus. Morphological analysis indicated 3 types of hemocytes were present, prohemocytes, plasmatocytes, and granular cells. Prohemocytes were small round cells with a high nuclear/cytoplasmic ratio. Plasmatocytes were the most abundant cell types in the hemolymph, and appeared as small to large and spindle-shaped cells with round or elongate nucleus, variable number of vacuoles, small granules, and pseudopodia. Granular cells were small to large and round with a large number of cytoplasmic granules, vacuoles, and numerous filopodia. Ultrastructurally, prohemocytes were undifferentiated with abundant free ribosomes and with few small electron-dense granules. Plasmatocytes were rich in mitochondria, rough endoplasmic reticulum, free ribosomes, small electron-dense granules, numerous peripheral vacuoles and with an important organelle polarization. Granular cells contained numerous large electron-dense granular inclusions and vacuoles. Cytochemical studies showed that plasmatocytes and granular cells have cationic bactericidal proteins. Only granular cells showed phenoloxidase and probably lysosomal activities. In vitro functional studies demonstrated that both plasmatocytes and granular cells were able to attach to glass slides, and only plasmatocyte had phagocytic activity and motility. These results characterize the hemocytes of An. albimanus and suggest that plasmatocytes and granular cells may have a role in defense responses to foreign organisms.

Establishment and characterization of a cell line from the mosquito Anopheles albimanus (Diptera: Culicidae).

A new cell line designated LSB-AA695BB, was established from embryos of the mosquito Anopheles albimanus. The primary culture was initiated in April, 1995, and the first passage was made 48 days later. Serial subcultures of the cells have been carried through 90 passage from Abril 1995 to February 1996. The cells were grown at 28 degrees C in MK/VP12 medium, supplemented with 20% fetal bovine serum: the pH tolerance ranged between 6.8 to 7.0. The cells have also been adapted to MM/VP12 medium under the same pH, temperature and serum concentration. The majority of the cells were a fibroblast-type. Isozyme characterization showed a pattern similar to that of An. albimanus pupae and adults but distinct from Ae. taeniorhynchus and Ae. albopictus (C6/36) mosquito cell lines. The culture was shown to be free of mycoplasma, bacteria and fungi. Microsporidia contamination of transovarial transmission was controlled with 6.0 micrograms/ml of albendazole.

A new cytotype of Anopheles nuneztovari from western Venezuela and Colombia.

Cytogenetic analysis of the larval polytene chromosomes of Anopheles nuneztovari from 5 collection sites in Táchira and Zulia states northwest of the Andean Cordillera in western Venezuela and from 2 sites in the Department of Valle, western Colombia, revealed what appears to be a distinctive cytotype informally designated as An. nuneztovari C. Its chromosomes are homosequential with those of An. nuneztovari B from western Venezuela southeast of the Cordillera but differ in the presence of a well-defined chromocenter and unique inversion polymorphisms. The large complex inversion in western Venezuela, 2Lb, is present at a frequency of 0.263 and deviates significantly from Hardy-Weinberg equilibrium in 3 of the 5 sites. Two smaller inversions (2Lc and 2Ld) that are included in 2Lb are present in the Colombian samples at a frequency of 0.300.

Chromosomal differences in populations of Anopheles nuneztovari.

Anopheles nuneztovari from 3 localities in Brazil, 2 in Venezuela, and 1 in Colombia were subjected to chromosome analysis. The Venezuelan and Colombian populations, responsible for malaria transmission in certain areas of these countries, differ in an X-chromosome arrangement from the Brazilian specimens, the difference apparently being due to the fixation of an inversion in the homozygous state in one population. It was possible to identify 216 specimens from Venezuela and Colombia and 190 from Brazil by the X-chromosome. A. nuneztovari and its close relatives may be easily distinguished in this way. Diagnostic descriptions of the chromosomes and a standard map, based on the Brazilian population, are provided.