ABSTRACT
The present study applied the comet assay to erythrocytes of Oreochromis niloticus with the aim of improving protocols to detect DNA damage in these cells, by using two distinct pHs (pH = 12.1 and pH > 13) and evaluating whether there is a correspondence between silver and ethidium bromide staining. Comets were visually examined and, the frequency of cells with and without damage was obtained, as well as the distribution of classes and scores. By using the Kruskal-Wallis test, our results revealed that pH 12.1 is more effective, although both pHs can be used. Our findings also suggest that silver staining can substitute ethidium bromide, an expensive and highly toxic stain that requires specific equipment for examination.
Subject(s)
Animals , Comet Assay , DNA Damage , Erythrocytes , Fishes/genetics , Ethidium , Silver Staining , Mutagenicity TestsABSTRACT
The Gryllus genus represents one the most complex in the Orthoptera systematic, characterized by a set of cosmopolite and cryptic species, many of them already described. This study compared the songs emitted by Gryllus specimens collected on the UNESP campus in Rio Claro (SP) and the pars stridens morphology and morphometry, to use the results to recognize possible cryptic species and contribute to the discussion of speciation processes. Three groups of crickets were discriminated by differences in the pars stridens and calling songs, characterized by different rhythms, frequencies and note composition, that indicated the presence of three species in the location analyzed, that presented few morphological differences. It is suggested from the results that the use of the pars stridens characteristics and the calling song as diagnostic traits is essential in the Gryllus taxonomy.
O gênero Gryllus destaca-se com um grande número de espécies descritas e representa um dos mais complexos gêneros na sistemática dos Orthoptera, caracterizado por um conjunto de espécies cosmopolitas e crípticas. Este trabalho compara os sons emitidos por espécimens de Gryllus coletados no campus da UNESP em Rio Claro (SP), bem como a morfologia e morfometria das pars stridens, com o objetivo de aplicar os resultados no reconhecimento de possíveis espécies crípticas e contribuir na discussão de processos de especiação. Três grupos de grilos foram discriminados por diferenças nas pars stridens e sons de chamado, caracterizados por diferentes ritmos, freqüências e composição das notas, indicando assim, a presença de três espécies no local analisado, morfologicamente pouco distintas. Diante dos resultados, sugere-se a utilização das características da pars stridens e do som de chamado como caracteres diagnósticos imprescindíveis na taxonomia dos Gryllus.