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Registros recuperados: 14
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Comparative analysis of spermiogenesis and sperm ultrastructure in Callichthyidae (Teleostei: Ostariophysi: Siluriformes) Neotropical Ichthyology
Spadella,Maria A.; Oliveira,Claudio; Quagio-Grassiotto,Irani.
In Corydoradinae, the presence of spermatids in the lumen of the testicular tubules together with spermatozoa suggests that spermatogenesis is of the semicystic type, whereas in Callichthyinae, sperm production occurs entirely within spermatocysts in the germinal epithelium, characterizing cystic spermatogenesis. Spermiogenesis in Callichthyinae is characterized by an initial lateral development of the flagellum, the presence of nuclear rotation to different degrees, an eccentric or medial formation of a nuclear fossa, formation of a cytoplasmic channel, and presence of centriolar migration, being more similar to type I spermiogenesis. In Corydoradinae, spermiogenesis is characterized by eccentric development of the flagellum, the absence of nuclear...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Catfish; Spermatid; Spermatozoa; Phylogeny; Morphology.
Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252007000300014
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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
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Comparative description and discussion of spermiogenesis and spermatozoal ultrastructure in some species of Heptapteridae and Pseudopimelodidae (Teleostei: Siluriformes) Neotropical Ichthyology
Quagio-Grassiotto,Irani; Spadella,Maria Angélica; Carvalho,Márcio de; Oliveira,Claudio.
The data obtained in the present study on spermiogenesis and spermatozoal ultrastructure of Pseudopimelodidae and Heptapteridae show that they share some characteristics, but greatly differ from each other. The main differences are the occurrence of type I spermiogenesis in Pseudopimelodidae and type III in Heptapteridae, the presence of nuclear fossa in Pseudopimelodidae and its absence in Heptapteridae, the presence of long midpiece in Pseudopimelodidae and short midpiece in Heptapteridae, the presence of cytoplasmic canal in Pseudopimelodidae and its absence in Heptapteridae, the presence of many large vesicles in the midpiece of Pseudopimelodidae and the presence of very long vesicles placed in the peripheral distal region in Heptapteridae, and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Catfish; Spermatid; Sperm; Structure; Phylogeny.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000300008
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Cytogenetic studies in three species of Lutjanus (Perciformes: Lutjanidae: Lutjaninae) from the Isla Margarita, Venezuela Neotropical Ichthyology
Nirchio,Mauro; Rondón,Rodolfo; Oliveira,Claudio; Ferreira,Irani A.; Martins,Cesar; Pérez,Julio; Sola,Luciana; Rossi,Anna Rita.
In the present study, three species of Lutjaninae, Lutjanus analis, L. griseus and L. synagris, were analyzed by conventional Giemsa staining, C-banding and silver staining, to reveal active Nucleolus Organizer Regions (NORs). Fluorescent in situ hybridization (FISH) was also applied to establish the number and location of the ribosomal gene clusters (18S and 5S rRNA genes). Counts of diploid metaphasic cells revealed a diploid modal chromosome complement composed of 48 acrocentric chromosomes in both L. analis and L. griseus. Two cytotypes were observed in L. synagris: cytotype I, with 2n=48 acrocentric chromosomes, found in 19 specimens, and cytotype II, with 46 acrocentric chromosomes and one large metacentric, found in two specimens. The large...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Karyotype; Ribosomal genes; NOR polymorphism; C-banding; Robertsonian rearrangement.
Ano: 2008 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252008000100012
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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
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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
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Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps(Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela Neotropical Ichthyology
Oliveira,Claudio; Nirchio,Mauro; Granado,Ángel; Levy,Sara.
Fish of the family Prochilodontidae are considered one of the most important components of commercial and subsistence fishery in freshwater environments in South America. This family consists of 21 species and three genera. In the present study, the karyotypes of Prochilodus mariae, Semaprochilodus kneri, and S. laticeps from Caicara del Orinoco, Bolivar State, Venezuela were studied. The species P. mariae, S. kneri and S. laticeps exhibited 2n=54 chromosomes (40 metacentric and 14 submetacentric), a single chromosome pair with nucleolus organizer regions, and a large amount of heterochromatin found at centromeric and pericentromeric positions in almost all chromosomes. The P. mariae specimens studied displayed 0 to 3 supernumerary microchromosomes. The...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Karyotype; C-band; NOR banding; Chromossome evolution; Characiformes.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100005
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New species of Moenkhausia Eigenmann, 1903 (Characiformes: Characidae) with comments on the Moenkhausia oligolepis species complex Neotropical Ichthyology
Benine,Ricardo C.; Mariguela,Tatiane C.; Oliveira,Claudio.
A new species of Moenkhausia is described from tributaries of the rio Paraguay, Brazil. The new species is diagnosed from congeners by characters related to body coloration, the number of lateral line scales, the degree of poring of the lateral line, and number of scales rows above and below the lateral line. Molecular analyses using partial sequences of the mitochondrial gene Cytochrome Oxidase I from specimens of the new species and specimens belonging to morphologically similar species demonstrated that the new species is easily differentiated by their high genetic distance and by their position in the phylogenetic hypothesis obtained through the Maximum Parsimony methodology. The analyses of three samples of M. oligolepis also revealed that they have...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Taxonomy; Systematic; Molecular Phylogeny; COI gene; Moenkhausia sanctaefilomenae.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252009000200005
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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
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Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae) on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences Neotropical Ichthyology
Mendonça,Fernando Fernandes; Oliveira,Claudio; Gadig,Otto Bismarck Fazzano; Foresti,Fausto.
Sharks of the genus Rhizoprionodon can be considered some of the most important predators along the trophic coastal marine ecosystems and represent an important economic resource for the small-scale fisheries, especially on the Brazilian coastline. In order to analyze the population structure of the shark Rhizoprionodon lalandii of São Paulo, Southeastern coast of Brazil, levels of genetic diversity were identified by nucleotide sequence analyses of the mitochondrial DNA control region. The results obtained from this study present moderate values of haplotype diversity and low nucleotide diversity. Although the AMOVA tests (ΦST = 0.08394, P < 0.01) had shown slightly differences among the studied samples, evidence for the occurrence of population...
Tipo: Info:eu-repo/semantics/article Palavras-chave: D-loop; Haplotypes; Mitochondrial control region; Shark conservation.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252009000200012
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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
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Revision of the genus Pseudotocinclus (Siluriformes: Loricariidae: Hypoptopomatinae), with descriptions of two new species Neotropical Ichthyology
Takako,Adriana Kazue; Oliveira,Claudio; Oyakawa,Osvaldo Takeshi.
The genus Pseudotocinclus is revised and two new species are described: Pseudotocinclus juquiae from the Ribeira de Iguape basin and Pseudotocinclus parahybae from the rio Paraíba do Sul basin. The presence of a small naked area on the snout tip distinguishes P. tietensis from P. parahybae and P. juquiae, which have the snout tip covered with small platelets. In addition, P. tietensis has four transverse dark-brown bands on the dorsum coalesced with the midlateral stripe instead of three, as in its congeners. Pseudotocinclus juquiae is distinguished from its congeners by having the orbital ring very prominent and conspicuous, a characteristic not found in P. tietensis or P. parahybae. These three species also differ from their congeners by meristic and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Taxonomy; South America; Biogeography; Brazil; Coastal drainages.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000400007
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Spermiogenesis and spermatozoa ultrastructure in five species of the Curimatidae with some considerations on spermatozoal ultrastructure in the Characiformes Neotropical Ichthyology
Quagio-Grassiotto,Irani; Gameiro,Maria Carolina; Schneider,Tatiana; Malabarba,Luiz Roberto; Oliveira,Claudio.
Spermiogenesis in the curimatid species, Steindachnerina insculpta, Cyphocharax gillii, C. modestus, C. spilotus, and Potamorhina altamazonica, is characterized by lateral development of the flagellum, nuclear rotation, eccentric nuclear fossa formation, and chromatin compacted into thick fibers. These spermatozoa exhibit a spherical head containing a nucleus with the chromatin highly condensed into thick fibers with small electron-lucent areas, and no acrosome. The nuclear fossa is of the moderate type and eccentric and penetrated by the centriolar complex. The midpiece is small, has many elongate vesicles, and a short cytoplasmic channel. Mitochondria may be elongate, branched or C-shaped, and are separated from the initial segment of the axoneme by the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fish; Spermatid; Sperm; Ultrastructure.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252003000100004
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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
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