Avaliação da diversidade genética de Sitophilus zeamais, Motschulsky, 1855 (Coleoptera: Curculionidae) utilizando isoenzimas em amostras de diversas regiões do Brasil e do Paraguai

O manejo das principais pragas de grãos armazenados tem sido feito, preferencialmente, com o uso de inseticida o que representa um enorme risco no desenvolvimento de resistência. Há muitos estudos com o Sitophilus zeamais visando seu controle, porém poucos analisando a variabilidade genética desta espécie. Este trabalho teve como objetivo estimar a variabilidade genética de S. zeamais em 10 amostras de diferentes localidades, destas, oito são do Brasil: Tunápolis (SC), Iguatemi (PR), Piracicaba (SP), Coimbra (MG), Maracaju (MS), Canarana (MT), Jataí (GO), Picos (PI) e duas são do Paraguai: Amambay e Pedro Juan Caballero. Para tal, foi utilizada a técnica de eletroforese de isozimas, em gel de amido para analisar seis sistemas enzimáticos (AAT, ACP, GPI, IDH, MDH e ME) e em gel de poliacrilamida que permitiu analisar uma enzima (EST). Concluiu-se que a espécie apresenta alta variabilidade genética (He), diferenciação moderada entre as amostras e as amostras foram agrupadas em três grupos

Biochemical comparison of two Hypostomus populations (Siluriformes, Loricariidae) from the Atlântico Stream of the upper Paraná River basin, Brazil

Two syntopic morphotypes of the genus Hypostomus - H. nigromaculatus and H. cf. nigromaculatus (Atlântico Stream, Paraná State) - were compared through the allozyme electrophoresis technique. Twelve enzymatic systems (AAT, ADH, EST, GCDH, G3PDH, GPI, IDH, LDH, MDH, ME, PGM and SOD) were analyzed, attributing the score of 20 loci, with a total of 30 alleles. Six loci were diagnostic (Aat-2, Gcdh-1, Gpi-A, Idh-1, Ldh-A and Mdh-A), indicating the presence of interjacent reproductive isolation. The occurrence of few polymorphic loci acknowledge two morphotypes, with heterozygosity values He = 0.0291 for H. nigromaculatus and He = 0.0346 for H. cf. nigromaculatus. FIS statistics demonstrated fixation of the alleles in the two morphotypes. Genetic identity (I) and distance (D) of Nei (1978) values were I = 0.6515 and D = 0.4285. The data indicate that these two morphotypes from the Atlântico Stream belong to different species

Allozyme differentiation of two populations of the genus Neoplecostomus Eigenmann & Eigenmann, 1888 (Teleostei, Loricariidae) from the upper Paraná River basin, Brazil

Allozyme electrophoresis was used to examine 12 enzymatic systems in two populations of the genus Neoplecostomus from the Paraná River basin. Samples of Neoplecostomus sp. 1 were collected in Paraitinguinha stream of the Tietê River basin, in the municipality of Salesópolis, São Paulo State, and those of Neoplecostomus sp. 2 from São Domingos stream of the Rio Grande River basin, in the municipality of Muzambinho, Minas Gerais State. The genetic variability of the two populations was estimated by Nei’s expected heterozygosity and was considered lower than average for populations of freshwater fish. The proportion of polymorphic loci was low (only 5.26% for the locus Idh). The low frequency of heterozygosity for both populations revealed a high fixation of alleles for each locus. Homozygote excess was observed in both populations. The values of Nei’s genetic identity and the presence of loci with different allele frequencies in both populations may imply that the two populations belong to different species. The genetic variability between populations was compared to other data for loricariids