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	Provedor de dados International Journal of Morphology (1) Autor Haque,Azimul (1) Haque,Ziaul (1) Quasem,Md. Abul (1) Palavra-chave Cortex (1) Medulla (1) Morphometry (1) Oocyte (1) Ovarian follicles (1) Tipo do documento Journal article (1) Ano 2016 (1) País Chile (1) Idioma Inglês (1)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 52 Primeira ... 1 2 3 ... Última Estimated frequency of B-chromosomes and population density of Astyanax scabripinnis paranae in a small stream Braz. J. Genet. Porto-Foresti,Fábio; Oliveira,Claudio; Maistro,Edson Luis; Foresti,Fausto. A study was made of the frequency of B-chromosomes and the population density of Astyanax scabripinnis paranae (Pisces, Characidae, Tetragonopterinae) from three stretches of the Cascatinha stream (Botucatu, SP). In the first stretch the population was estimated to be about 212 individuals and among 35 karyotyped specimens, 23 carried one macro B-chromosome; in the second stretch the population was estimated to be about 650 individuals and among 20 specimens karyotyped, two possessed one macro B-chromosome; in the third stretch the population was estimated to be about 107 individuals and among 10 specimens karyotyped, one carried one macro B-chromosome. A significant difference was observed in the frequency of macro B-chromosomes in females (57%) and males... Tipo: Info:eu-repo/semantics/article Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000300004 Nuclear DNA content of thirty species of Neotropical fishes Genet. Mol. Biol. Carvalho,Margarida Lima; Oliveira,Claudio; Foresti,Fausto. The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or... Tipo: Info:eu-repo/semantics/article Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100009 Comparative cytogenetic and morphological analysis of Astyanax scabripinnis paranae (Pisces, Characidae, Tetragonopterinae) Genet. Mol. Biol. Maistro,Edson Luis; Oliveira,Claudio; Foresti,Fausto. Cytogenetic and morphological studies were carried out on nine local populations of Astyanax scabripinnis paranae. All populations exhibited 2n = 50 chromosomes as well as conspicuous differences involving karyotype morphology, number and position of nucleolar organizer regions (NORs) and amount and/or locations of constitutive heterochromatin blocks. A quantitative study of the cytogenetic data showed that eight populations possessed different karyotypes. Morphological analyses based on nine measurements and two meristic parameters were effective in establishing clear identification of five populations. Comparative analysis of cytogenetic and morphological traits suggests that chromosomal changes have occurred at a more rapid rate than morphological... Tipo: Info:eu-repo/semantics/article Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200005 R- and G-band patterns in Astyanax scabripinnis paranae (Pisces, Characiformes, Characidae) Genet. Mol. Biol. Maistro,Edson Luis; Foresti,Fausto; Oliveira,Claudio. The absence of longitudinal bands in fish chromosomes has been associated with technical problems in chromosome preparations or the absence of a structural compartmentalization in the fish genome. In the present study, a R-banding pattern was obtained using a replication banding technique by in vivo treatment with 5-bromodeoxyuridine (5-BrdU). G-banding patterns were obtained after trypsin treatment and also after chromosome cleavage by in situ treatment with the restriction endonuclease BamHI. A similar G-banding pattern was also obtained after cleavage with the endonuclease HinfI. Presence of a resolute R- and G-banding patterns shows that Astyanax scabripinnis paranae chromosomes could present an isochore-like structure similar to that found in other... Tipo: Info:eu-repo/semantics/article Ano: 1999 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200011 Analysis of the synaptonemal complex of the nine-banded armadillo, Dasypus novemcinctus Genet. Mol. Biol. Scavone,Márcia Denise da Paixão; Oliveira,Claudio; Bagagli,Eduardo; Foresti,Fausto. The synaptonemal complex (SC) of three specimens of the nine-banded armadillo (Dasypus novemcinctus) was analyzed. Thirty-two bivalents (2n = 64) were observed, 31 of them being autosomes and one an XY sexual bivalent. Chromosome synapsis processes and nucleolus structure changes were analyzed in zygotene and pachytene cells, allowing a detailed description of the beginning of meiotic prophase in this species. There was complete synapsis of X and Y chromosomes. Some abnormalities in SC were observed in cells during zygotene and at the beginning of pachytene, but not in cells in the middle and late pachytene, suggesting the occurrence of synaptic adjustments in their SC. Tipo: Info:eu-repo/semantics/other Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000300020 Sympatric occurrence of two cytotypes of Astyanax scabripinnis (Characiformes, Characidae) Genet. Mol. Biol. Maistro,Edson Luis; Oliveira,Claudio; Foresti,Fausto. Among four specimens of Astyanax scabripinnis sympatrically collected from the Tamanduá stream (State of São Paulo, Brazil), three, named cytotype I, had 2n = 50 chromosomes (6M + 26SM + 4ST + 14A) and a fundamental number (FN) of 86, and one specimen, named cytotype II, had 2n = 48 chromosomes (6M + 28SM + 4ST + 10A) and FN = 86. Besides the difference in diploid number, the cytotypes showed a clear difference in the distribution of constitutive heterochromatin. One NOR-bearing chromosome pair was detected in both cytotypes and one specimen of cytotype I had multiple NORs (tree chromosome pairs). Robertsonian translocations and an increase or loss of heterochromatin are proposed to explain the karyotypic divergence observed. Some aspects related to the... Tipo: Info:eu-repo/semantics/other Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200021 Description of a ZZ/ZW sex chromosome system in Thoracocharax cf. stellatus (Teleostei, Characiformes, Gasteropelecidae) Genet. Mol. Biol. Carvalho,Margarida Lima; Oliveira,Claudio; Foresti,Fausto. The family Gasteropelecidae is composed of three genera and eight species. This study shows that Thoracocharax cf. stellatus has 2n = 52 chromosomes for both sexes. The five males studied showed 8 metacentric, 16 submetacentric, 4 subtelocentric, and 24 acrocentric chromosomes; the seven females showed only one submetacentric chromosome, belonging to pair 11, and one extra acrocentric chromosome, smaller than all the other chromosomes, characterizing the presence of a ZZ/ZW sex chromosome system in this species. Nucleolus organizing regions (NORs) were detected on the short arms of the subtelocentric chromosome pair 13. Constitutive heterochromatin was identified at pericentromeric and terminal positions in almost all chromosomes. The W chromosome was... Tipo: Info:eu-repo/semantics/article Palavras-chave: Sex chromosomes; ZW; DNA content; Fish; Evolution. Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000300008 Analysis of NOR distribution in cultivated and naturalized stocks of rainbow trout (Oncorhynchus mykiss) Genet. Mol. Biol. Porto-Foresti,Fábio; Oliveira,Claudio; Tabata,Yara A.; Rigolino,Marcos G.; Foresti,Fausto. In salmonid species, nucleolar organizing regions (NORs) have frequently been found on a single chromosome pair. However, some other, smaller yet active NORs have also been described. In the present study, NORs were found to be located in different positions on the chromosomes of 12 rainbow trout samples (11 cultivated and one naturalized stocks). Three phenotypes were found: 1) NORs located on two submetacentric chromosomes, in a subterminal position on the short arm (AA); 2) NORs located on two submetacentric chromosomes, in a subterminal position on the long arm (BB); and 3) NORs located on two submetacentric chromosomes, one in a subterminal position on the short arm, and the other in a subterminal position on the long arm (AB). Phenotype AA was... Tipo: Info:eu-repo/semantics/article Palavras-chave: NOR polymorphism; Fish cytogenetics; Rainbow trout. Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000400009 Nuclear DNA content determination in Characiformes fish (Teleostei, Ostariophysi) from the Neotropical region Genet. Mol. Biol. Carvalho,Margarida Lima; Oliveira,Claudio; Navarrete,Maria Clara; Froehlich,Otávio; Foresti,Fausto. In the present study, nuclear DNA content was analyzed in 53 species of Characiformes fish from the Neotropical region. Diploid number ranged from 2n = 48 in Astyanax fasciatus, Gymnocorymbus ternetzi and Hyphessobrycon griemi to 2n = 102 in Potamorhina squamoralevis, with a modal number of 54 chromosomes. Nuclear DNA content ranged from 1.70 ± 0.04 pg of DNA per diploid nucleus in Acestrorhynchus pantaneiro to 3.94 ± 0.09 pg in Tetragonopterus chalceus. A general analysis showed a mean value of 2.9 pg of DNA per diploid nucleus. Very similar DNA content values were observed in the species of the family Cynodontidae which showed a variation of 3% between the two genera studied. Small variations were observed between populations of Gymnocorymbus ternetzi,... Tipo: Info:eu-repo/semantics/article Palavras-chave: Nuclear DNA; DNA content; Chromosome; Fish; Evolution. Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000100010 Mitochondrial DNA variation in wild populations of Leporinus elongatus from the Paraná River basin Genet. Mol. Biol. Martins,Cesar; Wasko,Adriane P.; Oliveira,Claudio; Foresti,Fausto. 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.... Tipo: Info:eu-repo/semantics/article Palavras-chave: Conservation genetics; D-loop; Genetic variability; Leporinus elongatus; MtDNA. Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000100006 Cytogenetic analysis of five species of the subfamily Corydoradinae (Teleostei: Siluriformes: Callichthyidae) Genet. Mol. Biol. Shimabukuro-Dias,Cristiane Kioko; Oliveira,Claudio; Foresti,Fausto. In the present study, five callichthyid species belonging to the subfamily Corydoradinae were karyotyped: three species of Aspidoras and two of Corydoras. The three species of Aspidoras had the same diploid number, 2n = 46 chromosomes, similar karyotypic formulae, with most chromosomes metacentric or submetacentric, single interstitial Ag-NORs and C-band positive segments mainly found in the centromeric position. The comparative analysis of cytogenetic data available for the genus Aspidoras and other species of Corydoradinae suggest that several events of centric fusion occurred in the origin of the species of Aspidoras. The two analyzed species of Corydoras showed high diploid numbers, 2n = 74 in C. sodalis and 2n = 90 in C. britskii. While C. sodalis... Tipo: Info:eu-repo/semantics/article Palavras-chave: Fish cytogenetic; Karyotype; NOR; C-banding; Karyotypic evolution. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400014 Nuclear DNA content in 20 species of Siluriformes (Teleostei: Ostariophysi) from the Neotropical region Genet. Mol. Biol. Fenerich,Paulo César; Foresti,Fausto; Oliveira,Claudio. In the present study, 20 species of Siluriformes fish were analyzed in order to determine their nuclear DNA content and compare these data with their diploid number. In addition, the extension and importance of the changes that occurred during the process of diversification in the group of Neotropical freshwater catfish were investigated. The only species studied of the family Doradidae, Rhinodoras d'orbignyi (2n = 58), presented 3.46 ± 0.13 pg of DNA. Among the species of the family Heptapteridae, the values of nuclear DNA content and the diploid numbers ranged from 1.13 ± 0.09 pg of DNA in Pimelodella sp. (2n = 46) to 2.38 ± 0.07 pg of DNA in Imparfinis mirini (2n = 58). The family Loricariidae showed the widest variation in diploid number and nuclear... Tipo: Info:eu-repo/semantics/article Palavras-chave: Nuclear DNA; DNA content; Chromosome; Fish; Evolution. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000300008 A lethal effect associated with polymorphism of the NOR-bearing chromosomes in rainbow trout (Oncorhynchus mykiss) Genet. Mol. Biol. Porto-Foresti,Fábio; Oliveira,Claudio; Gomes,Eduardo A.; Tabata,Yara A.; Rigolino,Marcos G.; Foresti,Fausto. Cytogenetic analysis of a rainbow trout stock showed that the nucleolar organizing regions were located subterminally on the long arm of a submetacentric chromosome pair and occurred as a single chromosomal segment (phenotype N1) or as two chromosomal segments separated by a short euchromatic segment (phenotype N2). Cytogenetic analysis also showed that there were N1N1 and N1N2 individuals but no N2N2 individuals. Analysis of the different includedphenotypes incluted that the population was not in Hardy-Weinberg equilibrium (chi² = 19.333; p < 0.01), and that a higher frequency of individuals had the N1N2 phenotype. Experimental crosses involving four males (two N1N1 and two N1N2) and four females (one N1N1 and three N1N2) yielded eight broods. There... Tipo: Info:eu-repo/semantics/article Palavras-chave: NOR polymorphism; Paracentric inversion; Fish cytogenetics; Rainbow trout. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000100009 Karyotype description of five species of Trichomycterus (Teleostei: Siluriformes: Trichomycteridae) Genet. Mol. Biol. Sato,Luciana Ramos; Oliveira,Claudio; Foresti,Fausto. Trichomycteridae is a family of small catfish which are widely distributed throughout Southern Central America and South America. The present study showed that the cis-Andean species Trichomycterus florensis, Trichomycterus sp. aff. Trichomycterus itatiyae, Trichomycterus reinhardti, Trichomycterus davisi and Trichomycterus auroguttatus had 2n = 54 chromosomes (42 metacentric, 10 submetacentric and 2 subtelocentric), with T. reinhardti, T. auroguttatus and T. sp. aff. T. itatiyae exhibiting only one chromosome pair with silver-stained nucleolus organizer regions (NORs). The cytogenetic data suggest the existence of at least two groups of species in the cis-Andean representatives of the genus Trichomycterus. In the first group the first metacentric pair is... Tipo: Info:eu-repo/semantics/article Palavras-chave: Chromosome evolution; NOR banding; Fish. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000100008 Cytotaxonomic diagnosis of Trichomycterus diabolus (Teleostei: Trichomycteridae) with comments about its evolutionary relationships with co-generic species Neotropical Ichthyology Torres,Rodrigo A.; Oliveira,Claudio; Foresti,Fausto. The karyotype and the Ag-NOR location of a sample of Trichomycterus diabolus collected in the córrego Hortelã (Botucatu, São Paulo, Brazil) are described. The species exhibited 2n=56 chromosomes (42 metacentrics, 12 submetacentrics and 2 subtelocentrics) and the nucleolus organizing region located near to the centromere on the long arm of the largest metacentric pair. The presence of 2n=56 chromosomes in T. diabolus is an interesting characteristic since until now all cis-Andean species karyotyped presented 2n=54 chromosomes while almost all trans-Andean species presented different diploid numbers. The possible origin of this unexpected karyotypic form is discussed. Tipo: Info:eu-repo/semantics/article Palavras-chave: Trichomycterinae; Karyotype; Chromosome evolution; Fish cytogenetic. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300003 Biologia populacional de Astyanax altiparanae Garutti &amp; Britski (Teleostei, Characidae) do médio Rio Paranapanema, Paraná, Brasil Zoologia Orsi,Mário Luís; Carvalho,Edmir Daniel; Foresti,Fausto. O objetivo desse trabalho foi a determinação da estrutura populacional da espécie. Foram escolhidos quatro locais de amostragem com características ambientais distintas na bacia do rio Tibagi. As amostragens foram realizadas mensalmente no período de janeiro de 1997 a fevereiro de 1998. Um total de 1553 indivíduos foram capturados, apresentando constância em todos os trechos, com as maiores abundâncias nos trechos do rio Congonhas (76 %). Variações ocorreram entre os trechos por fase de desenvolvimento e classes de comprimento e na distribuição espacial, demonstrando que a espécie apresenta estrutura populacional diferenciada. A espécie apresentou grande capacidade adaptativa exploratória, utilizando estratégias diferenciadas na estrutura da população. A... Tipo: Info:eu-repo/semantics/article Palavras-chave: Ecologia; Peixes; Tibagi. Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752004000200008 Surprising genomic diversity in the Neotropical fish Synbranchus marmoratus (Teleostei: Synbranchidae): how many species? Neotropical Ichthyology Torres,Rodrigo Augusto; Roper,James Joseph; Foresti,Fausto; Oliveira,Claudio. Chromosomes and nuclear DNA content variation in the eel Synbranchus marmoratus were studied in seven samples taken from rio Paraguay and rio Paraná basins to examine whether karyotype and nuclear DNA content variations could offer useful information for the characterization of independent evolutionary lineages in the genus and construction of evolutionary and biogeographical hypotheses. The occurrence of different karyotypes was already described for this species; however, a new cytotype from rio Miranda was discovered. Nuclear DNA content showed a wide variation among samples and individuals, ranging from 5.2 to 9.1 pg of DNA/nuclei. An analysis of variance confirmed the occurrence of significant differences among samples. In a deeper series of analyses,... Tipo: Info:eu-repo/semantics/article Palavras-chave: Fish DNA; Chromosomes; Genome diversity; Karyotype; Synbranchus marmoratus. Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000200005 Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes) Genet. Mol. Biol. Santos,Lessandra Viviane de Rosa; Foresti,Fausto; Wasko,Adriane Pinto; Oliveira,Claudio; Martins,Cesar. 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... Tipo: Info:eu-repo/semantics/article Palavras-chave: Cyphocharax modesta; Steindachnerina insculpta; 5S rDNA; Chromosomes; FISH; Nucleotide sequence. Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000200009 Karyological characterization of four Neotropical fish species of the genus Hisonotus (Teleostei, Loricariidae, Hypoptopomatinae) from distinct Brazilian river basins Genet. Mol. Biol. Andreata,Artur Antonio; Oliveira,Claudio; Foresti,Fausto. The karyotypes of four Hisonotus species (two provisionally-named species A and D, H. nigricauda, and H. leucofrenatus) were found to have the same diploid number of 2n = 54 and interstitial silver-staining nucleolus organizer regions (Ag-NORs) located on the long arm of the largest metacentric pair. The C-banding pattern appeared to be species-specific, with one group (H. nigricauda and the unnamed species A and D) being characterized by small amounts of positive C-banded segments and containing a sub-group (species A and D) identified by a large positive C-banded segment on a small metacentric chromosome pair. The second group contained different samples of H. leucofrenatus, characterized by a larger amount of C-band positive segments spread over several... Tipo: Info:eu-repo/semantics/article Palavras-chave: Fish cytogenetics; Karyotypes; Ag-NORs; C-band; Chromosome evolution. Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100013 Seminal analysis, cryogenic preservation, and fertility in matrinxã fish, Brycon cephalus (Günther, 1869) BABT Ninhaus-Silveira,Alexandre; Foresti,Fausto; Veríssimo-Silveira,Rosicleire; Senhorini,José Augusto. Aiming to improve fish reproduction techniques, the characterization and cryopreservation of semen of Brycon cephalus were performed. The seminal characteristics observed were: an almost transparent, milky semen with a mean volume of 4mL, and sperm concentration of 9.617±1.630 x 10(6) spermatozoa/mm³. Spermatozoa (length = 31.288 ±4.47µm) were of the aquasperm type and displayed a small, round head (length = 1.727 ±0.18 µm; width = 1.752 ±0.17µm) without acrosomal vesicle, nucleus with highly condensed chromatin forming coarse clots and centriolar complex located in the nuclear fossa; a midpiece (length = 2.561±0.44µm), narrowed rearward, with a cytoplasmic canal; and a flagellum (length = 29.521 ±4.37µm). Fertilization tests with thawed semen demonstrated... Tipo: Info:eu-repo/semantics/article Palavras-chave: Semen characteristics; Cryopreservation; Brycon cephalus; Ultrastructure; Fish. Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000500015 Registros recuperados: 52 Primeira ... 1 2 3 ... Última

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