Physical chromosome mapping of repetitive DNA sequences in Nile tilapia Oreochromis niloticus: Evidences for a differential distribution of repetitive elements in the sex chromosomes

Repetitive DNAs have been extensively applied as physical chromosome markers on comparative studies, identification of chromosome rearrangements and sex chromosomes, chromosome evolution analysis, and applied genetics. Here we report the characterization of repetitive DNA sequences from the Nile tilapia (Oreochromis niloticus) genome by construction and screening of plasmid library enriched with repetitive DNAs, analysis of a BAC-based physical map, and hybridization to chromosomes. The physical mapping of BACs enriched with repetitive sequences and C(o)t-1 DNA (DNA enriched for highly and moderately repetitive DNA sequences) to chromosomes using FISH showed a predominant distribution of repetitive elements in the centromeric and telomeric regions and along the entire length of the largest chromosome pair (X and Y sex chromosomes) of the species. The distribution of repetitive DNAs differed significantly between the p arm of X and Y chromosomes. These findings suggest that repetitive DNAs have had an important role in the differentiation of sex chromosomes. (c) 2007 Elsevier Ltd. All rights reserved.

The use of the oxidative stress responses as biomarkers in Nile tilapia (Oreochromis niloticus) exposed to in vivo cadmium contamination

Water contaminants have a high potential risk for the health of populations. Protection from toxic effects of environmental water pollutants primarily involves considering the mechanism of low level toxicity and likely biological effects in organisms who live in these polluted waters. The biomarkers assessment of oxidative stress and metabolic alterations to cadmium exposure were evaluated in Nile tilapia, Oreochromis niloticus. The fish were exposed to 0.35, 0.75, 1.5, and 3.0 mg/l concentrations of Cd2+ (CdCl2) in water for 60 days. Fish that survived cadmium exposure showed a metabolic shift and a compensatory development for maintenance of the body weight gain. We observed a decreased glycogen content and decreased glucose uptake in white muscle. Lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities were also decreased, indicating that the glycolytic capacity was decreased in this tissue. No alterations were observed in total protein content in white muscle due to cadmium exposure suggesting a metabolic shift of carbohydrate metabolism to maintenance of the muscle protein reserve. There was an increase in glucose uptake, CK increased activity, and a clear increase of LDH activity in red muscle of fish with cadmium exposure. Since no alterations were observed in lipoperoxide concentration, while antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were changed in the liver and the red and white muscle of fish with cadmium exposure, we can conclude that oxygen free radicals are produced as a mediator of cadmium toxicity. Resistance development is related with increased activities of antioxidant enzymes, which were important in the protection against cadmium damage, inhibiting lipoperoxide formation. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Analytical approach to the metallomic of Nile tilapia (Oreochromis niloticus) liver tissue by SRXRF and FAAS after 2D-PAGE separation: Preliminary results

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Application of the comet assay in erythrocytes of Oreochromis niloticus (Pisces): a methodological comparison

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Induction of micronucleus and nuclear alterations in fish (Oreochromis niloticus) by a petroleum

In this study, micronucleus and nuclear alterations tests were performed on erythrocytes of Oreochromis niloticus (Perciformes, Cichlidae) in order to evaluate the water quality of the Atibaia river, in an area that receives effluents discharge of a petroleum refinery and also to evaluate the effectiveness of the treatments used by the refinery. Water samples were collected in five different sites related with a refinery from São Paulo State, Brazil. For the micronucleus and nuclear alterations tests, O. niloticus specimens were exposed for 72 h to the water samples and in pure ground water (negative control). The results herein obtained indicated that the treatments used by the refinery diminished the cytogenetic damage; however they were not fully effective, since the final mill has induced damages in the genetic material of the test organism. (C) 2008 Elsevier B.V. All rights reserved.

Genomic organization and comparative chromosome mapping of the U1 snRNA gene in cichlid fish, with an emphasis in Oreochromis niloticus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Visual communication stimulates reproduction in Nile tilapia, Oreochromis niloticus (L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Oxidative stress in Nile tilapia (Oreochromis niloticus) and armored catfish (Pterygoplichthys anisitsi) exposed to diesel oil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biochemical biomarkers in Oreochromis niloticus exposed to mixtures of benzo[a]pyrene and diazinon.

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hematological parameters in Nile Tilápia, Oreochromis niloticus exposed to sub-letal concentrations of mercury

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Triguilho na alimentação da tilápia do nilo (Oreochromis niloticus L.): digestibilidade e desempenho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Colina e betaína em rações purificadas na nutrição da tilápia do Nilo (Oreochromis niloticus)

Problemas metabólicos observados em produções intensivas de tilápias do Nilo (Oreochromis niloticus) têm sido relacionados à deficiência de colina nas rações. Com o objetivo de avaliar o efeito da suplementação dietética da colina na nutrição da espécie, rações purificadas contendo 0; 375; 750; 1.125; 1.500 ou 1.875 mg de cloreto de colina por kg, foram administradas ad libitum por 42 dias a tilápias do Nilo (5,09 ± 0,14 g), estocados em gaiolas de PVC atóxico (volume = 60 L), alojadas em caixas de polipropileno de 1000 L, em ambiente com condições controladas de temperatura e luminosidade, num delineamento experimental em blocos incompletos casualizados, com três parcelas por bloco (n=5). O ganho de peso (GDP) e o índice de conversão alimentar (ICA) de todos os tratamentos foram superiores ao controle. Não foram observadas diferenças para a quantidade de lipídios no fígado e tecido corporal, e sobrevivência (S%). Num segundo experimento, os peixes foram alimentados com rações suplementadas com 1.250 ou 2.500 mg de cloreto de colina por kg; ou 1.000; 2.000 ou 3.000 mg de betaína por kg. Não foram observadas diferenças significativas para S% e acúmulo de lipídeos hepáticos ou corporais; o ICA e GDP dos tratamentos suplementados com colina foram superiores aos dos tratamentos suplementados com betaína, mas não diferiram entre si. Níveis de suplementação superiores a 375 mg de cloreto de colina por kg de alimento melhoram o ICA e o GDP da tilápia do Nilo, mas a betaína não substitui efetivamente a colina em rações para a espécie.