Vicente Gomes

Biomonitoring of the genotoxic potential (micronucleus and erythrocyte nuclear abnormalities assay) of the Admiralty Bay water surrounding the Brazilian Antarctic Research Station “Comandante Ferraz,” King George Island

The micronucleus (Mn) and other kinds of erythrocyte nuclear abnormality (ENA) assays were used to assess the genotoxic potential of the seawater in front of the Brazilian Antarctic Research Station “Comandante Ferraz” (King George Island). In two consecutive summers, the fish Trematomus newnesi was exposed to the seawater in front of the fuel storage tanks and the sewage discharge outlet of the Station in laboratory bioassays and in situ caging assays. After the exposure, frequencies of ENA and Mn were scored on blood smears. Significantly higher Mn and ENA frequencies in relation to those of the controls were observed in fish exposed to both types of water, in both types of experiment. Seawater in front of the fuel tanks and sewage discharge outlet at the Station was found to induce the formation of micronuclei and other ENAs, indicators of genotoxicity. The need for further investigation and the suitability of the methods for screening mutagenic pollution in polar waters are discussed.

EROD activity and genotoxicity in the seabob shrimp Xiphopenaeus kroyeri exposed to benzo[a]pyrene (BaP) concentrations

Seabob shrimp Xiphopenaeus kroyeri is a marine species that lives in shallow waters of coastal environments, often impacted by polycyclic aromatic hydrocarbons (PAH) pollution. In the present study, seabob shrimp were exposed for 96 h to benzo[a]pyrene (BaP) at the nominal concentrations of 100, 200, 400 and 800 microg-L(-1). Animals of the control groups were exposed either to clean water or to the BaP-carrier (DMSO). At the end of the exposures, muscle tissues were sampled for BaP uptake assessment and hepatopancreas and hemolymph for EROD enzyme activity and hemocytes DNA damage, respectively. EROD activity and DNA damage increased significantly as a function of BaP exposure concentrations. Significant correlations between BaP uptake and both EROD activity and DNA damage suggest that they can be used as suitable tools for integrated levels of study on the biomarkers of PAH exposure.

Photo-induced toxicity of anthracene in the Antarctic shallow water amphipod, Gondogeneia antarctica

The photo-induced toxicity of anthracene was investigated as the mortality in Antarctic shallow water amphipod, Gondogeneia antarctica, at different concentrations of anthracene and different periods of exposure to natural sunlight and artificial UVA and UVB radiations. When exposed to natural sunlight, animals contaminated in the dark and placed in clean water or in anthracene solutions showed different degrees of mortality, dose–time dependent. Effects were even more evident when these animals were exposed to artificial UVA or UVB radiations. Depuration seemed to be a slow process. The effects of UV radiation and anthracene alone and the effects of the interactions of these two stressors implied that solar radiation is an important parameter that deserves consideration in the environmental assessment of polycyclic aromatic hydrocarbons in Antarctic coastal waters. G. antarctica proved to be a good bioindicator for the phototoxicity of anthracene in Antarctic shallow waters.

Karyotypes of three species of marine catfishes from Brazil

Os cromossomos de 3 especies de peixes da familia Ariidae - Netuma barba, Genidens genidens e Arius parkeri - foram estudados apos coloracao convencional com Giemsa. As tres especies apresentaram numero modal diploide de 2n = 56. O cariotipo de N. barba compreende 18 pares de cromossomos metacentricos (m), 18 submetacentricos (sm), 18 subtelocentricos (st) e 2 telocentricos (t); o de G. genidens compreende 12 pares m, 20 sm, 20 st e 41; o de A.parkeri compreende 16 m, 16 sm, 22 st e 2 t. Os resultados obtidos sao comparados entre si e com os de outros ariideos encontrados na literatura.

Preliminary study on chromosomes of Antarctic krill, Euphausia superba Dana

SummaryMeiotic chromosomes of antarctic krill, Euphausia superba Dana, collected at Admiralty Bay, are described and the method used to obtain this genetic material is reported. Forty seven dividing meiotic nuclei at diakinesis and metaphase I from seminal glands of four males were examined, all with n= 17 bivalents. The results were compared with those obtained by other workers using krill specimens from the opposite side of the Antarctic continent and apparent differences in chromosome numbers were observed. Possible reasons for these differences and the potential for using cytogenetic techniques to study populations of krill are discussed.

The karyotype of cathorops sp, a marine catfish from brazil

Foram realizados estudos cromossomicos em 25 especimens de Cathorops sp pelo metodo de air-drying. O numero modal diploide encontrado foi de 54 cromossomos sendo 1 par m + sm, 6 pares m, 6 pares sm e 14 pares st. Os resultados sao comparados com dados da literatura referentes a cromossomos de outros ariideos, principalmente de Ariopsis felis e Arius dussumieri.

Estudos cariotípicos de peixes da família Sciaenidae (Teleostei, Perciformes) da região de Cananéia, SP, Brasil: 2. Sobre o cariótipo de Menticirrhus americanus (Linnaeus, 1758)

Estudou-se o cariotipo de Menticirrhus americanus (Linnaeus, 1758), peixes teleosteos da familia Sciaenidae, coletados na regiao estuarino-lagunar de Cananeia, SP, Brasil. Foram realizadas preparacoes de cromossomos mitoticos e meioticos e ensaios de bandeamentos C e G. O numero diploide encontrado para a especie foi de 2n = 48 cromossomos, tipo t cujos tamanhos variaram entre 3,18 µm e 1,47 µm, em media, do maior para o menor par. O primeiro par de homologos apresenta uma constriccao secundaria no terco superior dos cromossomos. O numero haploide encontrado foi n = 24. O conteudo diploide de DNA foi de 1,57 ± 0,03 picogramas por celula. Nao se obteve padrao nitido de bandas G, mas a aplicacao da tecnica facilitou a identificacao de alguns pares adjacentes e a visualizacao da constriccao secundaria. Bandas C localizam-se, principalmente, nas regioes pericentrometricas.

Environmental Assessment of Admiralty Bay, King George Island, Antarctica

Monitoring has been developed by Antarctic Programmes such as Antarctic New Zealand (www.antarcticanz.govt.nz) and the US Antarctic Programme (USAP) (http://www.usap.gov) considering expansion of human activities and inevitable environmental.

Chromosomes of the Antarctic amphipod Waldeckia obesa Chevreux

Mitotic and meiotic chromosomes of the Antarctic lysianassoid amphipod Waldeckia obesa are described. The modal chromosome number is n = 25 and 2n = 50. The potential applications of cytogenetical studies in this group are discussed.

Micropogonias furnieri (Desmarest, 1823): estudo quali-quantitativo da variação ontogenética do padrão eletroforético de proteínas gerais do cristalino

Foram analisadas as possiveis variacoes do padrao eletroforetico de proteinas gerais do cristalino de Micropogonias furnieri (Desmarest, 1823), em funcao do desenvolvimento ontogenetico, do sexo e do ciclo de maturacao das gonadas, com vistas a sua utilizacao em estudos populacionais. Foram analisados, por eletroforese em acetato de celulose, cristalinos de 546 exemplares com comprimento total entre 98 e 710 mm, coletados no periodo de fevereiro de 1975 a fevereiro de 1976, na costa sudeste do Brasil (23oS - 29oS), area ocupada pela populacao I da especie (Vazzoler, 1971). 0 padrao geral obtido foi dividido em 4 conjuntos com 8 fracoes proteicas. Para individuos de mesmo tamanho nao foram constatadas diferencas entre os padroes do cristalino esquerdo e direito, entre padroes de machos e femeas e entre padroes de exemplares com gonadas em diferentes estadios de maturidade. Entretanto, ocorrem acentuadas variacoes quali-quantitativas relacionadas ao desenvolvimento ontogenetico. O conjunto I sofre marcada queda em sua concentracao relativa, enquanto os conjuntos II, III e IV apresentam incremento. 0 conjunto II sofre variacoes qualitativas, apresentando 2 fracoes para individuos jovens (ate 300-350 mm) e apenas uma nos adultos. As fracoes I, II-l, II-2, III-3 e IV-2 apresentam variacoes mais acentuadas ate a classe de 300-350 mm; ocorre estabilizacao da concentracao relativa das fracoes II-1, II-2 e III-3 a partir de 300-350 mm, e da I e IV-2 a partir de 450-500 mm. As fracoes III-1, III-2 e IV-1 apresentam pequenas variacoes, sendo praticamente constantes. Desse modo, para utilizacao dos padroes eletroforeticos de proteinas dos cristalinos como marcadores genetico-bioquimicos em estudos sobre variacoes intra-especificas, algumas estrategias devem ser consideradas, de acordo com os objetivos do estudo: a - comparar apenas as fracoes que se mostraram estaveis durante o desenvolvimento (III-1, III-2, IV-1); b - comparar padroes de exemplares dentro de um estreito intervalo de comprimentos; c - comparar fracoes que variam, apenas para individuos com comprimentos a partir dos quais a concentracao dessas fracoes ja se estabilizou (II-2 e III-3 a partir de 300 mm, e I e IV-2 de 450 mm); d - comparar os padroes globais de individuos que integram o extrato adulto da populacao, quando ja ocorreu estabilizacao do numero e da concentracao das fracoes proteicas. Esta ultima estrategia (d) parece ser a mais viavel, tanto a nivel interespecifico quando a finalidade e restrita a delimitacao espacial de populacoes, como em estudos taxonomicos de niveis superiores, quando nao ha problemas na classificacao de formas jovens.