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| Registros recuperados: 45 | |
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| Pires Bione,Nilton Cesar; Suely Pagliarini,Maria; Alves de Almeida,Leones. |
| A spontaneous male-sterile, female-fertile mutation affecting bivalent arrangement at the metaphase plate and cytokinesis was detected in line BR98-197 of the soybean breeding program developed by Embrapa - National Soybean Research Centre. Untill diakinesis, meiosis was normal with chromosome pairing as bivalents. From this phase, in several meiocytes, bivalents were not able to organize a single metaphase plate and remained scattered in the cytoplasm in a few or several groups. In these meiocytes, chromosomes segregated in both divisions giving rise to several micronuclei. However, the main cause of male sterility was the absence of cytokinesis after telophase II. Instead of the typical tetrads of microspores, four nucleate coenocytic microspores were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glycine max; Meiosis; Metaphase plate; Cytokinesis; Male sterility. |
| Ano: 2005 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0327-95452005000200004 |
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| Ferreira,Kátia; Torres,Giovana Augusta; Carvalho,Isabelle Vilela de; Davide,Lisete Chamma. |
| The objective of this work was to compare the meiotic behavior and pollen grain viability of three species of Crotalaria. Slides for meiotic analysis were prepared by the air-drying technique. Pollen grain viability was measured by three staining procedures (Alexander's solution, tetrazolium chloride and fluorescein diacetate) and in vitro germination in a sucrose solution. Eight bivalents were observed, confirming previous reports on populations from other regions of Brazil, as well as from other countries. All species showed abnormal meiotic behavior as follows: in Crotalaria micans, cytomixis and abnormal chromosome pairing in diakinesis; in C. spectabilis, abnormal chromosome pairing in diplotene; in C. zanzibarica, shrunk nuclei in leptotene and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crotalaria; Cytogenetics; Cytomixis; Meiosis; Pollen grain viability. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2009001200012 |
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| Mendes-Bonato,Andréa Beatriz; Pagliarini,Maria Suely; Valle,Cacilda Borges do. |
| This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brachiaria; Interspecific hybrid; Meiosis; Spindle abnormality; Tropical grass. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100023 |
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| Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina. |
| In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023 |
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| Sousa,Saulo M.; Reis,Aryane C.; Gomes,Shaiany S.L.; Bernardo,Karina B.; Salimena,Fátima R.G.; Viccini,Lyderson F.. |
| The genus Heteropterys is one of the major genera in Malpighiaceae. However, few cytological and palynological studies were reported. The present work described for the first time the chromosome number, heterochromatin pattern, meiotic behavior, pollen viability and palynological aspects of Heteropterys ubellata, a very spread species. One large Brazilian population was evaluated using conventional techniques for meiotic studies and acetolyse to access the pollen morphology. The species showed 2n = 20 chromosomes, normal meiotic development and viable pollens. Great blocks of heterochromatin were observed around the centromers. DAPI staining was positive for centroeric heterochroatin, hile CMA3 ark as observed just at terinal regions of one pair of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome number; Heterochromatin pattern; Heteropterys umbellata; Malpighiaceae; Meiosis; Pollen viability. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652010000400009 |
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| Stavale,Leila Miguel; Schneider,Marielle Cristina; Araujo,Douglas; Brescovit,Antonio Domingos; Cella,Doralice Maria. |
| Theridiidae is a derived family within the Araneoidea clade. In contrast to closely related groups, the 2n(male) = 20+X1X2 with acro/telocentric chromosomes is the most widespread karyotype among the theridiid spiders. In this work, the cytogenetic analysis of Argyrodes elevatus revealed original chromosome features different from those previously registered for Theridiidae, including the presence of 2n(male) = 20+X with meta/submetacentric chromosomes. Most individuals of Nesticodes rufipes showed family conserved karyotype characteristics. However, one individual had a 2n(male) = 24 due to the presence of an extra chromosome pair, which exhibited regular behavior and reductional segregation during meiosis. After silver staining, mitotic cells exhibited... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome morphology; Cytogenetic; Meiosis; Nucleolar organizer region; Sex chromosome system. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400012 |
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| Bhaumik,Pranami; Ghosh,Priyanka; Ghosh,Sujay; Feingold,Eleanor; Ozbek,Umut; Sarkar,Biswanath; Dey,Subrata Kumar. |
| Abstract Alzheimer's disease and Down syndrome often exhibit close association and predictively share common genetic risk-factors. Presenilin-1 (PSEN-1) and Apolipoprotein E (APOE) genes are associated with early and late onset of Alzheimer's disease, respectively. Presenilin −1 is involved in faithful chromosomal segregation. A higher frequency of the APOE ε4 allele has been reported among young mothers giving birth to Down syndrome children. In this study, 170 Down syndrome patients, grouped according to maternal meiotic stage of nondisjunction and maternal age at conception, and their parents were genotyped for PSEN-1 intron-8 and APOE polymorphisms. The control group consisted of 186 mothers of karyotypically normal children. The frequencies of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome; Genetic polymorphism; Karyotype; Meiosis; Microsatellite markers. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000400577 |
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| RISSO-PASCOTTO, C.; MENDES-BONATO, A. B.; PAGLIARINI, M. S.; VALLE, C. B. do. |
| Em gramíneas forrageiras do gênero Brachiaria, populações poliplóides naturais são abundantes e geralmente apomíticas, enquanto as diploídes, que se reproduzem sexualmente, são raras. Considerando-se a estreita correlação existente entre poloploidia e apomixia neste gênero, e a necessidade de identificação de genótipos sexuais compatíveis para o sucesso de hibridação, conhecimentos de características citológicas básicas como modo de reprodução, comportamento meiótico e nível de ploidia tornam-se essenciais para direcionar os programas de melhoramento. Durante análises desenvolvidas na Universidade Estadual de Maringá, com acessos de várias espécies de uma coleção de germoplasma, mantida na Embrapa Gado de Corte, três acessos, sendo um B.... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Braquiária; Feed grasses.; Brachiaria Decumbens; Brachiaria Ruziziensis; Citogenética Vegetal; Gramínea Forrageira; Meiose; Poliploidia.; Cytogenetics; Polyploidy.; Meiosis. |
| Ano: 2003 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/324062 |
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| Pareja Ordóñez,Nancy Maricela; Santacruz Ordóñez,Nazira Katherine; Ordóñez Jurado,Héctor Ramiro; Lagos Burbano,Tulio César. |
| Se realizó un análisis del comportamiento meiótico de las especies de lulo S. hirtum, S. quitoense y S. sessiliflorum, siguiendo la metodología convencional para los estudios de microsporogénesis. Se tomaron botones florales en diferentes estados de desarrollo, fijándolos por 24 horas en una solución de tres partes de etanol por una parte de ácido acético, saturada con trazas de cristales de cloruro férrico. Para la preparación de las placas se siguió la técnica de aplastamiento, se liberaron las células madres del grano de polen y finalmente se hicieron las observaciones bajo microscopía de luz. El análisis mostró que la meiosis se presenta en longitudes de antera que van desde los 2,79 mm hasta los 4,45 mm. La normalidad meiótica fue del 100%, tanto para... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Meiosis; Variabilidad; Microsporogénesis; Índice meiótico; Normalidad meiótica. |
| Ano: 2010 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122010000400002 |
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| Mendes-Neto,Ernani de Oliveira; Vicari,Marcelo Ricardo; Campaner,Carlos; Nogaroto,Viviane; Artoni,Roberto Ferreira; Almeida,Mara Cristina. |
| Cytogenetic analysis of Astylus antis using mitotic and meiotic cells was performed to characterize the haploid and diploid numbers, sex determination system, chromosome morphology, constitutive heterochromatin distribution pattern and chromosomes carrying nucleolus organizer regions (NORs). Analysis of spermatogonial metaphase cells revealed the diploid number 2n = 18, with mostly metacentric chromosomes. Metaphase I cells exhibited 2n = 8II+Xyp and a parachute configuration of the sex chromosomes. Spermatogonial metaphase cells submitted to C-banding showed the presence of small dots of constitutive heterochromatin in the centromeric regions of nearly all the autosomes and on the short arm of the X chromosome (Xp), as well as an additional band on one of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sex chromosomes; Meiosis; Metaphase; FISH; 18S rDNA. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200007 |
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| Fradkin,Maia; Greizerstein,Eduardo; Paccapelo,Héctor; Ferreira,Víctor; Grassi,Ezequiel; Poggio,Lidia; Ferrari,María Rosa. |
| We studied three different tricepiros: (Don Santiago x Don Noé), (Cumé x Horovitz) and (Cumé x Don Noé). The tricepiro (Don Santiago x Don Noé) was obtained by crossing the triticale Don Santiago INTA (AABBRR, 2n = 6x = 42) with the trigopiro Don Noé INTA (AABBDDJJ, 2n = 8x = 56). The number of chromosomes for the F1 was 2n = 49, the most frequent meiotic configuration being 14 bivalents and 21 univalents. The univalents were situated in the periphery of the equatorial plane, whereas the bivalents were located in the central zone. The chromatids in some of the univalents split when bivalents underwent reductional division in anaphase I. There were few laggard chromosomes or chromatids at this phase. The number of chromosomes (2n = 48-58) was high and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hybrids; Meiosis; Tricepiro; Univalents; Reductional division. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400022 |
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| Adona,P.R.; Leal,C.L.V.. |
| The effect of concentration and exposure period of bovine oocytes to butyrolactone I (BLI) on meiotic block and in vitro maturation (IVM) kinetics was studied. In experiment 1, all oocytes were at germinal vesicle stage (GV), after 6h in culture with 0, 50 and 100µM BLI. After 12h, all oocytes cultured with 50 and 100µM BLI remained in GV. After 24h, less oocytes were in GV with 50µM (82%) than with 100µM BLI (99%, P<0.05). In experiment 2, after 6h IVM, 93% of control oocytes (IVM only) were in GV, while treated oocytes (100µM BLI for 6, 12 or 24h prior to IVM) showed less oocytes in GV with increased exposure period to BLI prior to IVM (83 and 73%, for 6h and 12h, P<0.05). For a 24h inhibition, GV rates were similar to 12h (70%, P>0.05). After... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bovine; Meiosis; Oocyte; Butyrolactone I; Kinetics; Nuclear maturation. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-09352006000300011 |
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| Hernández-Quintero,JD; Reyes-Valdés,MH; Mendoza-Rodríguez,DV; Gómez-Martínez,M; Rodríguez-Herrera,R. |
| El género Dasylirion es un grupo de plantas típicas del Desierto Chihuahuense, perennes, de un comportamiento sexual dioico y denominadas comúnmente sotoles. Es un género poco estudiado desde el punto de vista biológico y se desconocen las bases de su dinámica reproductiva. En este trabajo se estudió el número cromosómico y el comportamiento meiótico de Dasylirion cedrosanum en el municipio de Saltillo, Coahuila, una localidad del noreste de México. Para la preparación de cromosomas mitóticos se utilizó una técnica basada en un tratamiento enzimático con pectoliasa y celulasa, así como tinción con acetocarmín. Para el estudio meiótico se recolectaron botones florales masculinos, se fijaron y se tiñeron con el mismo colorante. Como resultado, se reportan... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dasylirion cedrosanum; Dioecia; Cromosomas; Mitosis; Meiosis. |
| Ano: 2015 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-56572015000100015 |
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| Registros recuperados: 45 | |
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