Consulta: creatorFacets:"Margarido,Vladimir Pavan"
Registros recuperados: 17
Data/hora: 09/06/2024 10:32:55

Natural triploidy in Leporinus cf. elongatus bearing sex chromosomes
Provedor de dados: Genetics and Molecular Biology
Autores: Molina,Wagner Franco; Margarido,Vladimir Pavan; Galetti Jr,Pedro Manoel.
Although several cases of natural triploidy in fish have already been described, spontaneous polyploidy in species with differentiated sex chromosomes are rare. We report the occurrence of a triploid fish (3n = 81) Leporinus cf. elongatus, a species characterized by a highly differentiated ZZ/ZW sex chromosome system, from the São Francisco river. The occurrence of a ZZZ triploid adult indicates the viability of this chromosome constitution in this fish.
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Polyploidy; Triploid fish; ZW chromosomes; Sex chromosomes; Anostomidae.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400010

Heterochromatin patterns and karyotype relationships within and between the genera Brycon and Salminus (Pisces, Characidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Margarido,Vladimir Pavan; Galetti Junior,Pedro Manoel.
Chromosomes of two Brycon species (B. lundii and B. microlepis) and Salminus hilarii were analyzed. Based on constitutive heterochromatin distribution patterns, karyotypic relationships within and between Bryconinae and Salmininae were examined. A monophyletic origin for the genus Brycon, comprising at least two chromosome synapomorphies (presence of two large submetacentric bearing paracentromeric and telomeric heterochromatin), is suggested. Moreover, Bryconinae and Salmininae may represent a monophyletic unit among Characidae, as they share several chromosome features.
Tipo: Info:eu-repo/semantics/article
Ano: 1999
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300012

Karyotypic differentiation through chromosome fusion and number reduction in Imparfinis hollandi (Ostariophysi, Heptapteridae)
Provedor de dados: Genetics and Molecular Biology
Autores: Margarido,Vladimir Pavan; Moreira-Filho,Orlando.
The Neotropical Heptapteridae fish Imparfinis hollandi, endemic to the Iguaçu River Basin (Brazil), was cytogenetically analyzed and the diploid chromosome number of 2n = 42 chromosomes was determined (22m + 10sm + 10st), the lowest diploid number in this genus and family. Like other Heptapteridae species, only one NOR-bearing chromosome pair was detected by silver nitrate staining. Dark heterochromatic blocks were visualized in only three chromosome pairs, and chromomycin A3+ bands were coincident with Ag-NORs. Although no intercalary (TTAGGG)n sequence was observed through FISH with a telomere probe, an asymmetric karyotype showing four large chromosome pairs with diploid chromosome number reduction suggests that tandem chromosome fusions probably...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Siluriformes; Chromosome banding; Chromosomal rearrangements; (TTAGGG)n.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200012

Cytogenetic analyses of two endemic fish species from the São Francisco River basin: Conorhynchus conirostris and Lophiosilurus alexandri (Siluriformes)
Provedor de dados: Genetics and Molecular Biology
Autores: Marques,Marilza Barbosa de Almeida; Moreira-Filho,Orlando; Garcia,Caroline; Margarido,Vladimir Pavan.
Two Siluriformes species endemic to the São Francisco River basin were characterized by conventional and differential cytogenetic analyses involving C-banding, Ag-nucleolar organizer region (NOR) and chromomycin A3 (CMA3) staining, and FISH (fluorescent in situ hybridization) with 18S and 5S rDNA probes. Conorhynchus conirostris presents a higher diploid number (2n = 60) than those detected in Pimelodidae representatives, whereas Lophiosilurus alexandri, with a karyotype of 2n = 54 chromosomes, presents a chromosomal constitution similar to that found in the family Pseudopimelodidae. Plesiomorphic characteristics such as single NORs at terminal positions are found in both species, as revealed by CMA3 and silver nitrate staining, and FISH with a 18S rDNA...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Incertae sedis; Pimelodidae; Pseudopimelodidae; RDNA; Siluriformes.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200008

Cytotaxonomy of Parodon nasus and Parodon tortuosus (Pisces, Characiformes): A case of synonymy confirmed by cytogenetic analyses
Provedor de dados: Genetics and Molecular Biology
Autores: Bellafronte,Elisangela; Margarido,Vladimir Pavan; Moreira-Filho,Orlando.
Morphological and cytogenetical studies were carried out on the freshwater fish Parodon nasus and Parodon tortuosus in order to evaluate a putative synonymy. The diploid chromosome number observed in both species was 2n = 54 (48M/SM and 6ST) with no differences between the sexes. Despite slight differences in the pattern of heterochromatin distribution and the number of cusps in symphysean teeth, the location of nucleolar organizer regions (NORs) and 5S rRNA genes (both species-specific features) were similar in both species. The remarkable similarity observed between these allopatric species supports recent taxonomical reviews indicating that P. tortuosus is a synonym for P. nasus.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; Parodontidae; Systematics; 18S rDNA; 5S rDNA.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000500010

Amplification of a GC-rich heterochromatin in the freshwater fish Leporinus desmotes (Characiformes, Anostomidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Margarido,Vladimir Pavan; Galetti Junior,Pedro Manoel.
This is the first description of the karyotype of Leporinus desmotes. The diploid female number was 2n = 54 meta- and submetacentric chromosomes. The nucleolar organizing regions (NORs) were studied by silver nitrate staining and rDNA fluorescence in situ hybridization (FISH) and were found to be located in the telomeric region of the long arm of the 9th pair. C-banding revealed centromeric and telomeric heterochromatin segments in most chromosomes. Intercalar blocks of heterochromatin were observed in the long arm of six chromosome pairs. Besides a NOR-adjacent heterochromatin, all of the intercalar heterochromatic segments were brightly fluorescent by mithramycin staining. These data suggest that a unique amplification of a primordial GC-rich...
Tipo: Info:eu-repo/semantics/article
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000300012

Contributions to the taxonomy of Trachelyopterus (Siluriformes): comparative cytogenetic analysis in three species of Auchenipteridae
Provedor de dados: Neotropical Ichthyology
Autores: Santos,Dayane Petik dos; Felicetti,Denise; Baumgärtner,Lucas; Margarido,Vladimir Pavan; Blanco,Daniel Rodrigues; Moreira-Filho,Orlando; Lui,Roberto Laridondo.
ABSTRACT Auchenipteridae is divided into subfamilies Centromochlinae and Auchenipterinae. Parauchenipterus is included in the latter and is subject of taxonomic discussions concerning its validation or synonymization with Trachelyopterus. Herein, three species from two hydrographic basins were cytogenetically analyzed: Parauchenipterus striatulus from Doce River and two sympatric species, P. galeatus and Trachelyopterus coriaceus, from the Araguaia River. Diploid number of 58 chromosomes was verified for all species, but P. striatulus has different karyotype formula from the others. The three species have heterochromatin located in terminal regions of almost all chromosomes and in pericentromeric region on acrocentric chromosomes. Simple NORs was verified...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cryptic species; FISH; Parauchenipterus; Problematic taxonomy; 5S rDNA.
Ano: 2021
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252021000100214

First chromosomal analysis of Gymnorhamphichthys britskii: the remarkable lowest diploid value within the family Rhamphichthyidae (Gymnotiformes)
Provedor de dados: Neotropical Ichthyology
Autores: Fernandes,Carlos Alexandre; Aguiar,Allan Kardec Moreira de; Paiz,Leonardo Marcel; Baumgärtner,Lucas; Piscor,Diovani; Margarido,Vladimir Pavan.
ABSTRACT Gymnorhamphichthys britskii is a Neotropical electric fish of family Rhamphichthyidae described from the Paraná-Paraguay system. This study reports the first karyotypic description of G. britskii collected from the upper Paraná river basin, which presented 2n=38 chromosomes, karyotype composed of 14 metacentric, 8 submetacentric, 2 subtelocentric and 14 acrocentric chromosomes, and fundamental number as 62 for both sexes. Heteromorphic sex chromosomes were absent. A single pair of nucleolar organizing regions (NORs) was detected in the submetacentric chromosome pair number 9 by silver staining and confirmed by the 18S rDNA probe. The 5S rDNA was located in a single chromosome pair. Heterochromatic regions were clearly observed in the short arms of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ag-NORs; C-banding; Fish cytogenetics; Karyotype evolution; Repetitive sequences.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300205

Cytogenetic markers as tools in delimiting species of the highly diverse Neotropical fish Bryconamericus (Characiformes: Characidae)
Provedor de dados: Neotropical Ichthyology
Autores: Prestes,Anahiê Bortoncello; Nardelli,Aline; Paiz,Leonardo Marcel; Gavazzoni,Mariane; Margarido,Vladimir Pavan.
ABSTRACT Bryconamericus is a highly diverse group of characid fishes, being cytogenetic a valuable tool for the delimitation of species. Bryconamericus aff. iheringii (Upper Uruguay/Lower Paraná), B. coeruleus (Upper Paraná), B. cf. ecai e B. cf. eigenmanni (Upper Uruguay) were studied cytogenetically, and presented 2n=52 chromosomes, with interpopulational/interspecific variation of karyotype and fundamental number. Heterochromatin was evidenced in pericentromeric, telomeric and interstitial regions, and it was shown to be an important cytogenetic marker. Single nucleolar organizing regions (NORs) were found in B. cf. eigenmanni, B. cf. ecai and B. aff. iheringii (Lower Paraná), and multiple in B. aff. iheringii (Upper Uruguay) and B. coeruleus, with...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome rearrangements; Co-localization; Cytotaxonomy; Cytosystematics; Intra and interspecific variation; Ribosomal genes.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252019000300203

Karyotypic diversity between allopatric populations of the group Hoplias malabaricus (Characiformes: Erythrinidae): evolutionary and biogeographic considerations
Provedor de dados: Neotropical Ichthyology
Autores: Blanco,Daniel Rodrigues; Lui,Roberto Laridondo; Bertollo,Luiz Antonio Carlos; Margarido,Vladimir Pavan; Moreira Filho,Orlando.
Three populations of the group Hoplias malabaricus from the hydrographic basins of the São Francisco, Araguaia/Tocantins and Xingu Rivers in Brazil were analyzed using classic cytogenetic methods (Giemsa staining, C-banding and Ag-NORs) and molecular methods (fluorescent in situ hybridization with 18S rDNA, 5S rDNA and 5SHindIII satellite DNA probes). The chromosome markers allowed the characterization of these populations as belonging to karyomorph A and the detection of inter-population divergences. These differences likely stem from different evolutionary histories resulting from geographic isolation between populations associated to the dispersive mode of these organisms, reinforcing genetic diversity in the group Hoplias malabaricus.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; Trahira; Karyomorph A; FISH; Geographic isolation.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252010000200015

Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition
Provedor de dados: Neotropical Ichthyology
Autores: Kowalski,Samantha; Paiz,Leonardo Marcel; da Silva,Maelin; Machado,Amanda de Souza; Feldberg,Eliana; Traldi,Josiane Baccarin; Margarido,Vladimir Pavan; Lui,Roberto Laridondo.
ABSTRACT Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Centromochlinae; Cytogenetics; Sex chromosome system; Taxonomy; ZZ/ZW.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252020000300203

Evidence of the color pattern variation in populations of Gymnotus pantanal (Gymnotiformes) from three streams in the upper Paraná River basin, Brazil
Provedor de dados: Neotropical Ichthyology
Autores: Frana,Vitor André; Graça,Weferson Júnio da; Gubiani,Éder André; Konerat,Jocicléia Thums; Margarido,Vladimir Pavan.
Color pattern is an important character in the systematics and alpha-taxonomy of electric fishes of the genus Gymnotus. This paper presents evidence of color variation in populations of G. pantanal found in the streams Jacutinga and Pinheirinho, in the upper Paraná River basin, southern Brazil. Color variations were corroborated for morphological and cytogenetic data. Our results show the importance of integrating morphologic and cytogenetic data in the taxonomy of the Gymnotus species.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gymnotidae; Gymnotus pantherinus species-group; La Plata River basin; Karyotype.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252011000200011

B chromosome and NORs polymorphism in Callichthys callichthys (Linnaeus, 1758) (Siluriformes: Callichthyidae) from upper Paraná River, Brazil
Provedor de dados: Neotropical Ichthyology
Autores: Konerat,Jocicléia Thums; Bueno,Vanessa; Baumgartner,Lucas; Martins-Santos,Isabel Cristina; Margarido,Vladimir Pavan.
B chromosomes are extra chromosomes from the normal chromosomal set, found in different organisms, highlighting their presence on the group of fishes. Callichthys callichthys from the upper Paraná River has a diploid number of 56 chromosomes (26 m-sm + 30 st-a) for both sexes, with the presence of a sporadically acrocentric B chromosome. Moreover, one individual presented a diploid number of 57 chromosomes, with the presence of a morphologically ill-defined acrocentric B chromosome in all analyzed cells. The physical mapping of 5S and 18S rDNA shows multiple 5S rDNA sites and only one pair of chromosomes with 18S sites in C. callichthys, except for two individuals. These two individuals presented a third chromosome bearing NORs (Ag-staining and 18S rDNA)...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: 18S rDNA; 5S rDNA; Chromosomal rearrangements; FISH; Supernumerary chromosome.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252014000300603

The role of chromosomal fusion in the karyotypic evolution of the genus Ageneiosus (Siluriformes: Auchenipteridae)
Provedor de dados: Neotropical Ichthyology
Autores: Lui,Roberto Laridondo; Blanco,Daniel Rodrigues; Martinez,Juliana de Fátima; Margarido,Vladimir Pavan; Venere,Paulo Cesar; Moreira Filho,Orlando.
Ageneiosus is the most widely distributed genus of the family Auchenipteridae among South American river basins. Although chromosome studies in the family are scarce, this genus has the largest number of analyzed species, with 2n = 54 to 56 chromosomes, differing from the rest of the family (2n = 58). This study aimed to analyze Ageneiosus inermis from the Araguaia River basin. The diploid number found was of 56 chromosomes. Heterochromatin was allocated in terminal region of most chromosomes, plus a pericentromeric heterochromatic block in pair 1, a pair distinguished by size in relation to other chromosomes pairs. AgNORs were detected in only one submetacentric chromosome pair, which was confirmed by FISH. 5S rDNA was present in only one metacentric...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: C banding; Cytogenetic Markers; [GATA]n sequence; RDNA-FISH; [TTAGGG]n sequence.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252013000200327

Update on the ichthyofauna of the Piquiri River basin, Paraná, Brazil: a conservation priority area
Provedor de dados: Biota Neotropica
Autores: Cavalli,Daiane; Frota,Augusto; Lira,Angelica Dorigon; Gubiani,Éder André; Margarido,Vladimir Pavan; Graça,Weferson Júnio da.
Abstract: Knowledge of the fish species in river basins is among the minimum requirements for the management of water and fish resources. Therefore, the aim of this study was to update the fish species composition of the Piquiri River basin, upper Paraná River basin. Data were gathered from recent information published in specialized literature and records for ichthyology collections. This update reports the occurrence of 152 fish species distributed in 8 orders, 31 families, and 89 genera. Non-native species accounted for 20% of all species, and the construction of the Itaipu Power Plant and its fish ladder were the main vectors of introduction. Three percent of the species were endangered, and 11% were classified as migratory. The Piquiri River basin...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ichthyofaunal survey; Species knowledge; Preservation; Upper Paraná River basin.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032018000200305

Cytogenetic studies in three species of the genus Oligosarcus
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Rubert,Marceléia; Margarido,Vladimir Pavan.
Karyotypic studies were carried out on three species of the genus Oligosarcus: O. paranensis, O. pintoi, and O. longisrostris. All of them showed a diploid number of 50 chromosomes and the same karyotypic formulae (4M + 10SM + 16ST + 20A). Silver nitrate staining revealed single NORs in O. longirostris and multiple NORs in O. paranensis and O. pintoi. Heterochromatin seemed to play an important role in the chromosomal diversification of these species. Based on cytogenetical data, speciation hypotheses within this group were proposed, reinforcing the importance of chromosomal studies for a better understanding of evolution within the genus Oligosarcus, as well as within the family Characidae.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetic studies; Oligosarcus; Acestrorhynchinae; Chromosome banding.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132007000100015

Cytogenetics and biogeography: considerations about the natural origin of Hoplias malabaricus (Characiformes, Erythrinidae) on the Iguaçu river
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Vicari,Marcelo Ricardo; Pazza,Rubens; Artoni,Roberto Ferreira; Margarido,Vladimir Pavan; Bertollo,Luiz Antonio Carlos.
Hoplias malabaricus (trahyra) is a widespread fish species over the Neotropical region with diversified inter-populational karyotypes (cytotypes), which may correspond to a species complex. Despite the wide distribution in the South American basins, some authors have questioned its natural origin in the Iguaçu river, an important Brazilian river basin which is characterized by several endemic fish species. We have analyzed the karyotype of H. malabaricus from different collection sites of this river, by conventional and banding methods. Our results, in addition to our previous data concerning geographic distribution of the cytotypes, contribute to better understand the origin of H. malabaricus on the Iguaçu river, reinforcing the proposition that it is a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; Karyotypes distribution; Endemism.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000300015