Two new species of Mycodrosophila (Diptera, Drosophilidae) proposed by molecular and morphological approaches, with a key to American species

ABSTRACT There are approximately 130 species of MycodrosophilaOldenberg, 1914 worldwide, although only nine species were recorded in American countries so far, three of which are exclusively Nearctic, five exclusively Neotropical and one found in both biogeographic regions (Mycodrosophila projectans). Such a small number of American species is likely a consequence of collecting bias, which favors the capture of frugivorous drosophilids, and to the general absence of Neotropical Mycodrosophila studies in the last 50 years. Here, we describe two commonly sampled species of Mycodrosophila from the Amazonian and Pampa Brazilian biomes, which share morphological similarities with Mycodrosophila neoprojectans and M. projectans, respectively. We compared sequences of the mitochondrial gene cytochrome oxidase subunit I (COI), external morphology characteristics and male terminalia among these species. Based on a DNA barcoding approach coupled to morphological differences, we proposed the delimitation of two new species, Mycodrosophila hofmanni sp. nov. and Mycodrosophila valentae sp. nov. An updated key to identifying Neotropical and Nearctic Mycodrosophila species is also provided.

Over-activation of the Drosophila melanogaster hsp83 gene by selenium intoxication

Selenium is an important dietary micronutrient and an essential component of selenoproteins and the active sites of some enzymes, although at high concentrations it is toxic. We investigated diphenyl diselenide ((C6H5)2Se2 ) for its effects on the developmental stages of Drosophila melanogaster and found that in the larval and pupae stages the toxic threshold for this compound when added to the banana-agar medium on which the larva were fed was 350 µmol. In adult flies, fed on the same media, there were no observable toxic effects below 500 µmol but there were toxic effects above 600 µmol, indicating that adult flies were more resistant to selenium intoxication. In larvae, a when diphenyl diselenide was present above the toxic threshold there was increased activation of the hsp83 heat shock protein gene. Selenium promotes oxidation of sulfhydryl groups and affects the folding of proteins and this could explain the over-expression of hsp83 because the product of this gene is involved in protein folding and defense responses, including the response to heat shock.

Transposable elements P and gypsy in natural populations of Drosophila willistoni

The presence and integrity of the P transposon and the gypsy retrotransposon in the genome of 18 samples of natural Drosophila willistoni populations collected from a large area of South America were Southern blot screened using Drosophila melanogaster probes. The aim of this screening was provide further knowledge-base on the geographical distribution of D. willistoni and to carry out an inter-population analysis of the P and gypsy elements present in the genomes of the populations analyzed. The fragment patterns obtained indicate that both the P and gypsy elements are ancient in the D. willistoni genome, but whereas the gypsy retroelement appears to be invariable and stable the P element varies between populations and appears to still have some capacity for mobilization.

A low-cost apparatus for transforming Drosophila and detecting green fluorescent protein (GFP) genetic markers

We describe the transformation of white mutant Drosophila simulans with a piggyBac transposon vector and a green fluorescent marker (GFP) and show how to construct inexpensive micro-manipulation and epifluorescence equipment for use in transposon-mediated germ-line transformation. Although the number of G0 adult flies (16) obtained in relation to the number of injected eggs was very low (12.5 percent) it was comparable to the proportion described by other authors and can be considered as a good rate of transformation.