Structural analysis of glycerol-3-phosphate dehydrogenase from several Drosophila species

Interpopulation variability among Panstrongylus megistus (Hemiptera: Reduviidae) from Brazil

Comparisons were made among Panstrongylus megistus (Burmeister) from three areas of Brazil (Bahia, Minas Gerais, and Santa Catarina), where populations differ with regard to their degree of association with human dwellings. The following characters were studied: morphology of the eggs and the male genitalia; morphometry of the head and thorax; isoenzyme profile; enzymatic activity of the alpha-glycerophosphate dehydrogenase (alpha-GPDH); and cytogenetics. In general, differences were observed in the weight, diameter, and length of the egg among Bahia, Minas Gerais, and Santa Catarina populations. Differences were not observed in the architecture of the egg exochorion. The size of the median process of the pygophore of the male genitalia of individuals from Bahia differed from the other two populations. The Minas Gerais population presented the largest number of denticles in the endosome process. The morphometry of the head and thorax differentiated Santa Catarina from the Bahia and Minas Gerais populations. Phosphoglucomutase (EC 5.4.2.2., PGM) was the only enzyme out of 11 that showed polymorphism; the population from Minas Gerais was most polymorphic, whereas the population from Santa Catarina was monomorphic. Study of the alpha-GPDH activity and cytogenetics did not reveal differences among the three populations. Analysis of all the characters studied together with information on these three populations from previous publications allowed a phenogram to be constructed. Two distinct groups were evident, one represented by Santa Catarina and the other by Bahia and Minas Gerais. Considering the greater variability of the Minas Gerais and Bahia populations, we propose the inclusion of these states within the area of origin of P. megistus.

alpha-glycerophosphate dehydrogenase activity in flight muscles of triatomine bugs Panstrongylus megistus and Triatoma sordida

The alpha-glycerophosphate dehydrogenase (alpha-GPDH) activity in flight muscles of Panstrongylus megistus and Triatoma sordida, vectors of Chagas disease in Brazil, was studied. Both species showed higher enzymatic activities in fliers than in non-fliers insects. T. sordida exhibited a higher proportion of flier insects than P. megistus. A possible role of alpha-GPDH on triatomines flight is discussed.

Low activity sn-glycerol-3-phosphate dehydrogenase variants in natural populations of Drosophila melanogaster

Eleven Australian natural populations of Drosophila melanogaster were screened by electrophoresis for evidence of null and/or low activity variants at the Gdph locus. Of 5018 alleles investigated, 57 had markedly lower GDPH activity, as judged by their heterozygous phenotypes, than control alleles. GPDH assays of 13 of these variant alleles showed that whilst they were heterogeneous in their properties and included electrophoretic variants and two categories of low-activity variant, there were no true null alleles. The most common low-activity variants exhibited dominance for GPDH activity in heterozygotes with normal alleles, and were shown to share this property with an allele previously isolated from a London (UK) population (Langley et al., 1981).

Sequence, structure and evolution of the gene coding for sn-glycerol-3-phosphate dehydrogenase in Drosophila melanogaster

We present the complete nucleotide and deduced amino acid sequence for the gene encoding Drosophila sn-glycerol-3-phosphate dehydrogenase. A transcription unit of 5kb was identified which is composed of eight protein encoding exons. Three classes of transcripts were shown to differ only in the 3'-end and to code for three protein isoforms each with a different C-terminal amino acid sequence. Each transcript is shown to arise through the differential expression of three isotype-specific exons at the 3'-end of the gene by a developmentally regulated process of 3'-end formation and alternate splicing pathways of the pre-mRNA. In contrast, the 5'-end of the gene is simple in structure and each mRNA is transcribed from the same promoter sequence. A comparison of the organization of the Drosophila and murine genes and the primary amino acid sequence between a total of four species indicates that the GPDH gene-enzyme system is highly conserved and is evolving slowly.

Molecular cloning and characterization of esterase-6, a serine hydrolase of Drosophila

The Est-6 gene of Drosophila melanogaster was cloned by screening libraries with synthetic oligonucleotides corresponding to tryptic peptides from purified esterase-6 (Est-6) protein. cDNA clones were isolated that hybridized in situ to the site of Est-6 on chromosome 3 at 69A1. Inserts in putative Est-6 cDNA clones were 1.85 kilobases (kb) long, and blot hybridization analysis of electrophoretically fractionated RNA, using a cDNA clone as a probe, revealed two transcripts, of 1.68 and 1.83 kb. The two transcripts showed the same developmental profile as the Est-6 protein. Neither transcript was detected in an Est-6-null line. The cDNA fragment was homologous to a 2.3-kb EcoRI-BamHI fragment in genomic clones, and this region was interrupted by the 8-kb B104 transposable element in the Est-6-null line. Conceptual translation of the cDNA sequence revealed a protein of 548 residues with 19% sequence similarity to acetylcholinesterase from the Torpedo ray.