Flebotomíneos do Estado de Tocantins, Brasil (Diptera: Psychodidae) / Phlebotomine sand flies in the State of Tocantins, Brazil (Diptera: Psychodidae)

Between 1997-1998, the authors carried out sporadic collection of sand flies in the municipalities of Paraíso de Tocantins, Monte do Carmo, Porto Nacional and Monte Santo all in the Tocantins State of northern Brazil. Human bait was used in Monte Santo and a battery operated light trap in other municipalities. The ecotypes chosen for the traps were in the peridomiciles, inside the houses, in the forest and the orchard. We identified 2,677 sand flies, belonging to 32 species. The most abundant species of sand flies were Lutzomyia whitmani, Lutzomyia longipalpis, Lutzomyia carmelinoi, Lutzomyia evandroi, Lutzomyia longipennis and Lutzomyia antunesi. Collections from the forest showed greater diversity of species, while the largest number of sand flies were caught around the houses. Several species known or suspected to be vectors of Leishmania in other regions of Brazil were captured.

Nos anos de 1997 e 1998 realizaram-se capturas esporádicas de flebotomíneos nos municípios de Paraíso de Tocantins, Monte do Carmo, Porto Nacional e Monte Santo, todos localizados no estado de Tocantins, região norte do Brasil, com o intuito de conhecer a fauna flebotomínica da região. No município de Monte Santo utilizou-se isca humana e nos demais armadilhas luminosas CDC. Os ecótopos utilizados foram: peridomicílio, intradomicílio, mata e pomar. Foram capturados 2.677 flebotomíneos, pertencentes a 32 espécies. As mais freqüentes foram Lutzomyia whitmani, Lutzomyia longipalpis, Lutzomyia carmelinoi, Lutzomyia evandroi, Lutzomyia longipennis e Lutzomyia antunesi. As capturas na mata apresentaram maior diversidade de espécies, enquanto no peridomicílio houve maior número de exemplares capturados. Foram capturadas neste estado várias espécies vetoras em outras regiões do Brasil.

Characterization of constitutive and putative differentially expressed mRNAs by means of expressed sequence tags, differential display reverse transcriptase-PCR and randomly amplified polymorphic DNA-PCR from the sand fly vector Lutzomyia longipalpis

Molecular studies of insect disease vectors are of paramount importance for understanding parasite-vector relationship. Advances in this area have led to important findings regarding changes in vectors' physiology upon blood feeding and parasite infection. Mechanisms for interfering with the vectorial capacity of insects responsible for the transmission of diseases such as malaria, Chagas disease and dengue fever are being devised with the ultimate goal of developing transgenic insects. A primary necessity for this goal is information on gene expression and control in the target insect. Our group is investigating molecular aspects of the interaction between Leishmania parasites and Lutzomyia sand flies. As an initial step in our studies we have used random sequencing of cDNA clones from two expression libraries made from head/thorax and abdomen of sugar fed L. longipalpis for the identification of expressed sequence tags (EST). We applied differential display reverse transcriptase-PCR and randomly amplified polymorphic DNA-PCR to characterize differentially expressed mRNA from sugar and blood fed insects, and, in one case, from a L. (V.) braziliensis-infected L. longipalpis. We identified 37 cDNAs that have shown homology to known sequences from GeneBank. Of these, 32 cDNAs code for constitutive proteins such as zinc finger protein, glutamine synthetase, G binding protein, ubiquitin conjugating enzyme. Three are putative differentially expressed cDNAs from blood fed and Leishmania-infected midgut, a chitinase, a V-ATPase and a MAP kinase. Finally, two sequences are homologous to Drosophila melanogaster gene products recently discovered through the Drosophila genome initiative

Biology of nymphs of Rhodnius robustus Larrousse, 1927 (Hemiptera, reduviidae), fed on pigeon or on Swiss mouse blood in laboratory conditions

The duration of the life cycle of Rhodnius robustus Larrousse, 1927 as well as the mortality rate of each nymphal instar were studied comparing groups fed on pigeon or on mouse blood weekly or fortnightly. This species showed a better development and lower mortality rate when fed on swiis mouse. The intervals between feedings apparently did not have influence on the shorteing of the cycle. We suggest that laboratoy colonies and experiments with R. robustus are better maintained when these triatomines are fed on swiss mouse.