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Search Results: 1 - 10 of 7493 matches for " Claudio;Wasko "
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Mitochondrial DNA variation in wild populations of Leporinus elongatus from the Paraná River basin
Martins, Cesar;Wasko, Adriane P.;Oliveira, Claudio;Foresti, Fausto;
Genetics and Molecular Biology , 2003, DOI: 10.1590/S1415-47572003000100006
Abstract: leporinus elongatus, a fish species widely distributed throughout the paraná river basin in south america, is an important fishery resource and a valuable species in aquaculture programs. despite its great economic importance, several wild populations have been suffering a drastic reduction. the comprehension of its population structure represents an important step for the conservation of these organisms in natural environments, and also for the selection of wild stocks to be used in hatchery programs. in order to understand the genetic-population structure of l. elongatus, d-loop mitochondrial dna analyses were applied in six wild populations of the species. the results were used to estimate the levels of within and among population genetic variability. although the d-loop variations could not be correlated to the geographic distribution of these organisms, it was possible to detect high levels of genetic variability within each population and the occurrence of exclusive population haplotypes, which suggests a partial genetic differentiation among them. the obtained data can be useful in selecting fish stocks that preserve a better genetic diversity of l. elongatus for use in conservation and/or hatchery programs.
Mitochondrial DNA variation in wild populations of Leporinus elongatus from the Paraná River basin
Martins Cesar,Wasko Adriane P.,Oliveira Claudio,Foresti Fausto
Genetics and Molecular Biology , 2003,
Abstract: Leporinus elongatus, a fish species widely distributed throughout the Paraná River basin in South America, is an important fishery resource and a valuable species in aquaculture programs. Despite its great economic importance, several wild populations have been suffering a drastic reduction. The comprehension of its population structure represents an important step for the conservation of these organisms in natural environments, and also for the selection of wild stocks to be used in hatchery programs. In order to understand the genetic-population structure of L. elongatus, D-loop mitochondrial DNA analyses were applied in six wild populations of the species. The results were used to estimate the levels of within and among population genetic variability. Although the D-loop variations could not be correlated to the geographic distribution of these organisms, it was possible to detect high levels of genetic variability within each population and the occurrence of exclusive population haplotypes, which suggests a partial genetic differentiation among them. The obtained data can be useful in selecting fish stocks that preserve a better genetic diversity of L. elongatus for use in conservation and/or hatchery programs.
Identification and description of distinct B chromosomes in Cyphocharax modestus (Characiformes, Curimatidae)
Santos, Lessandra Viviane De Rosa;Foresti, Fausto;Martins, Cesar;Oliveira, Claudio;Wasko, Adriane Pinto;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008000200019
Abstract: cytogenetic analyses were performed in cyphocharax modestus, collected at paranapanema river and tietê river (s?o paulo state, brazil). a karyotype with 2n = 54 chromosomes was observed in the animals from both brazilian freshwater river systems. one to four b chromosomes were also detected in individuals from the paranapanema river, which represents the probable first report of more than a single supernumerary element in a species of the curimatidae group. c-banding revealed centromeric and telomeric heterochromatin blocks in several chromosomes of the normal karyotype complement of c. modestus. moreover, while some b chromosomes were characterized by the complete absence of c-bands, others were totally heterochromatic. although there was a prevalence of b chromosomes in males of c. modestus, at least one supernumerary element was found in males and/or females of several other populations of the species, which suggests that the presence of these chromosomes seems to represent a general trait of c. modestus. a possible origin of the described b chromosomes may be related to the occurrence of a chromosome non-disjunction followed by the loss of euchromatic segments, an event that should have occurred in chromosomes that present conspicuous centromeric heterochromatic blocks and even in chromosomes that lack c-bands in this region, resulting in small supernumerary elements.
Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes)
Santos, Lessandra Viviane de Rosa;Foresti, Fausto;Wasko, Adriane Pinto;Oliveira, Claudio;Martins, Cesar;
Genetics and Molecular Biology , 2006, DOI: 10.1590/S1415-47572006000200009
Abstract: the 5s ribosomal dna (5s rdna) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5s rdna coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (nts). to contribute to knowledge on the organization and evolution of vertebrate 5s rdna we used pcr, nucleotide sequencing, southern blot hybridization and chromosome fluorescence in situ hybridization (fish) to investigate 5s rdna tandem repeats in the south american curimatidae fish steindachnerina insculpta and cyphocharax modesta. 5s rdna repeats of 180 base pairs (bp) from both species were pcr-generated and sequenced evidencing the shortest 5s rdna monomer so far described in eukaryote species. southern blotting revealed that both species contained two tandem 5s rdna classes, the pcr amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by pcr. chromosome mapping of the 5s rdna repeats identified a major locus in both species and a second minor locus only in c. modesta. the southern blot and chromosome mapping data indicate the presence of different types of 5s rdna tandem repeats in the curimatidae genome.
Discrimination of Shark species by simple PCR of 5S rDNA repeats
Pinhal, Danillo;Gadig, Otto BF;Wasko, Adriane P;Oliveira, Claudio;Ron, Ernesto;Foresti, Fausto;Martins, Cesar;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008000200033
Abstract: sharks are suffering from intensive exploitation by worldwide fisheries leading to a severe decline in several populations in the last decades. the lack of biological data on a species-specific basis, associated with a k-strategist life history make it difficult to correctly manage and conserve these animals. the aim of the present study was to develop a dna-based procedure to discriminate shark species by means of a rapid, low cost and easily applicable pcr analysis based on 5s rdna repeat units amplification, in order to contribute conservation management of these animals. the generated agarose electrophoresis band patterns allowed to unequivocally distinguish eight shark species. the data showed for the first time that a simple pcr is able to discriminate elasmobranch species. the described 5s rdna pcr approach generated species-specific genetic markers that should find broad application in fishery management and trade of sharks and their subproducts.
5S rDNA characterization in twelve Sciaenidae fish species (Teleostei, Perciformes): depicting gene diversity and molecular markers
Alves-Costa, Fernanda A.;Martins, Cesar;Matos, Fernanda Del Campos de;Foresti, Fausto;Oliveira, Claudio;Wasko, Adriane P.;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008000200025
Abstract: in order to extend the genetic data on the sciaenidae fish family, the present study had the purpose to characterize pcr-generated 5s rdna repeats of twelve species of this group through page (polyacrylamide gel electrophoresis) analysis. the results showed the occurrence of at least two different 5s rdna size classes in all the species. moreover, 5s rdna repeats of one of the studied species - isopisthus parvipinnis - were cloned and subjected to nucleotide sequencing and southern blot membrane hybridization analyses, which permitted to confirm the existence of two major 5s rdna classes. phylogenetic analysis based on the nucleotide sequences of different 5s rdna repeats of i. parvipinnis lead to their separation into two major clusters. these results may reflect the high dynamism that rules the evolution rate of 5s rdna repeats. the obtained data suggest that 5s rdna can be useful in genetic analyses to identify species-specific markers and determine relationships among species of the sciaenidae group.
A Review of Microsatellite Markers and their Application on Genetic Diversity Studies in Parrots  [PDF]
Flavia T. Presti, Adriane P. Wasko
Open Journal of Genetics (OJGen) , 2014, DOI: 10.4236/ojgen.2014.42010
Abstract:

The ability of a population to adapt to a changing environment depends on its genetic variation. Thus, the study of genetic diversity within and among species or populations is especially important on conservation biology scopes. One way to assess the genetic diversity is through the use of microsatellite molecular markers. Microsatellites have been widely used to answer population genetics issues as gene flow, parentage, and population structure, mostly resulting in data on the distribution of genetic variability within and among natural populations, which are essential for ex situ and in situ conservation procedures. As the Psittacidae family comprehends one of the birds group with the largest number of endangered species, studies that aim to investigate the genetic diversity of these animals may support their conservation. This article is a review of genetic data on parrots, through the use of microsatellite markers, that have been published since 2004.

Efficiency of pair formation in a model society
Mateusz Wasko,Krzysztof Kulakowski
Physics , 2006,
Abstract: In a recent paper a set of differential equations was proposed to describe a social process, where pairs of partners emerge in a community. The choice was performed on a basis of attractive resources and of random initial preferences. An efficiency of the process, defined as the probability of finding a partner, was found to depend on the community size. Here we demonstrate, that if the resources are not relevant, the efficiency is equal to unity; everybody finds a partner. With this new formulation, about 80 percent of community members enter to dyads; the remaining 20 percent form triads.
Identities among actin-encoding cDNAs of the Nile tilapia (Oreochromis niloticus) and other eukaryote species revealed by nucleotide and amino acid sequence analyses
Poletto, Andréia B.;Wasko, Adriane P.;Oliveira, Claudio;Azevedo, Alexandre;Carvalho, Robson F.;Silva, Maeli Dal Pai;Foresti, Fausto;Martins, Cesar;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008000200031
Abstract: actin-encoding cdnas of nile tilapia (oreochromis niloticus) were isolated by rt-pcr using total rna samples of different tissues and further characterized by nucleotide sequencing and in silico amino acid (aa) sequence analysis. comparisons among the actin gene sequences of o. niloticus and those of other species evidenced that the isolated genes present a high similarity to other fish and other vertebrate actin genes. the highest nucleotide resemblance was observed between o. niloticus and o. mossambicus a-actin and b-actin genes. analysis of the predicted aa sequences revealed two distinct types of cytoplasmic actins, one cardiac muscle actin type and one skeletal muscle actin type that were expressed in different tissues of nile tilapia. the evolutionary relationships between the nile tilapia actin genes and diverse other organisms is discussed.
Mapping 18S ribosomal genes in fish of the genus Brycon (Characidae) by fluorescence in situ hybridization (FISH)
Wasko, Adriane Pinto;Galetti Jr., Pedro Manoel;
Genetics and Molecular Biology , 2000, DOI: 10.1590/S1415-47572000000100025
Abstract: the present study provides data on the nucleolar organizer regions (nors) of seven brycon species based on mapping of the 18s rrna genes by fluorescence in situ hybridization (fish). fluorescent signals were observed on the telomere of the long arm of two large submetacentric chromosomes, thus confirming the number and location of nors previously revealed by other classical cytogenetic techniques. although there were no inter- or intra-individual variations in the number and location of the 18s loci, nor size polymorphism was observed between homologous chromosomes. the clustering and conservation of nors in a single chromosome pair indicates a high level of nor stability among species of the genus brycon.
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