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

Malaria no municipio de Humaita, Estado do Amazonas. XV - Inquerito parasitologico em dias consecutivos nos habitantes da regiao. / Malaria in the municipality of Humaita, State of Amazonas. XV - Parasitological survey in consecutive days in inhabitants of the region

Em agosto de 1979, foram estudados 293 individuos do Municipio de Humaita, dos quais 105 eram habitantes dos povoados situados as margens do Rio Madeira, 72 eram indios da Tribo Tenhairim e 116 residentes da zona urbana de Humaita. Cada individuo foi examinado de uma a quatro vezes em dias consecutivos. De todos foi feito esfregaco com sangue obtido pela digito-puncao, fixado pelo metanol, corado pelo Giemsa e lido em microscopio de imersao (1.000 X). Os resultados obtidos revelaram apenas 6 casos positivos (2,04%), sendo 3 habitantes do Rio Madeira e 3 indios. Este metodo, alem de trabalhoso, nao trouxe nenhuma contribuicao para o aumento de taxa de positividade em inquerito parasitologico realizado em area endemica