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| Registros recuperados: 45 | |
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| Almejo Vázquez,Lizette I.; Iglesias Andreu,Lourdes G.; Escobedo Gracia-Medrano,Rosa Maria. |
| RESUMEN El comportamiento meiótico es de gran importancia para el desarrollo de programas de mejoramiento genético, especialmente en especies como la vainilla (Vanilla planifolia Jacks.), que se ven severamente afectadas por diversos factores bióticos y abióticos derivados de su estrecha base genética. Por ello, el presente trabajo se planteó con el objetivo de evaluar el comportamiento meiótico del morfotipo comercial "Mansa" del municipio de Papantla de Olarte, Veracruz, México. Para ello, se colectaron botones florales de diferentes tamaños y se fijaron en Carnoy, utilizando la técnica de la calabaza, seguido de una tinción con acetocarmín al 2% (p/v) para observar claramente todas las etapas del proceso meiótico. Se observó un comportamiento meiótico... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citogenética; Cromosomas; Meiosis; Mejoramiento genético; Orchidaceae. |
| Ano: 2022 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2022000300464 |
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| TARAZONA¹,ARIEL; LÓPEZ,ANGELA; OLIVERA-ANGEL,MARTHA. |
| La producción de embriones in vitro ha sido una herramienta útil para el desarrollo de técnicas como la clonación y la transgénesis, que han revolucionado los campos de la ciencia y la tecnología. La técnica básica para la maduración, fertilización y cultivo in vitro de los embriones produce, desde sus inicios, bajas tasas de desarrollo hasta el estadío de blastocisto con índices reducidos de viabilidad de los mismos. Los avances en el conocimiento de la dinámica celular durante estos procesos condujo a la hipótesis, de que la maduración, entendida como el reinicio del ciclo meiótico, la reorganización del ooplasma y la regulación de la expresión génica, juegan un papel fundamental para sustentar el desarrollo temprano de los embriones, esta capacidad de... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Complejo folicular; Maduración; Meiosis; Ooplasma. |
| Ano: 2010 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2010000300001 |
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| Pessim, Cleide; UEM; Pagliarini, Maria Suely; UEM; Jank, Liana; Embrapa; Kaneshima, Alice Maria de Souza; Universidade Estadual de Maringá; Bonato, Andréa Beatriz Mendes; Universidade Estadual de Maringá. |
| Panicum maximum Jacq. is one of the most cultivated grasses in the world. The intraspecific hybridization breeding program underway at Embrapa Beef Cattle aims at combining several agronomic characteristics in a single plant with high seed production. Four intraspecific hybrids originated from the cross between sexual tetraploid female plants with apomictic tetraploid male plants, including the genitors, were cytologically evaluated in the meiotic process throughout conventional methodology. Hybrids and genitors showed high meiotic stability. The percentage of abnormal cells among them ranged from 6.7 to 14.2%. Abnormalities recorded were irregular chromosome segregation, chromosome stickiness, and absence of the first cytokinesis, but the latter did not... |
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Palavras-chave: 5.01.03.05-9 breeding program; Meiosis; Intraspecific hybrids; Panicum maximum 5.01.03.05-9 breeding program; Meiosis; Intraspecific hybrids; Panicum maximum. |
| Ano: 2010 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/6461 |
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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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| 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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| 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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| A fin de investigar las relaciones genómicas entre especies de la serie Turnera (x= 5), se lleva a cabo un programa de cruzamientos controlados y se obtuvieron numerosos híbridos. Entre las especies con flores amarillas de la serie Turnera, T. krapovickasii, T. scabra y T. subulata poseen citotipos diploide y autotetraploide. Hasta el momento se desconocen el grado de aislamiento reproductivo entre diploides y tetraploides y el grado de afinidad genómica de estas especies a nivel tetraploide. En este trabajo se presentan los resultados del análisis citogenético de los híbridos intraespecíficos triploides (2n=3x=15) de T. krapovickasii y T. scabra y los híbridos tetraploides (2n=4x=20) T. krapovickasii × T. scabra y T. subulata × T. scabra. En los híbridos... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Turnera; Meiosis; Relaciones genómicas; Triploides; Tetraploides. |
| Ano: 2017 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1851-23722017000400008 |
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| Godoy,Sara Mataroli de; Pereira,Andréia Rodrigues Alonso; Romagnolo,Mariza Barion; Risso-Pascotto,Claudicéia. |
| The Alchornea triplinervia specie belongs to the Euphorbiaceae family, one of the main families of the Brazilian flora. In order to contribute to a better understanding of the specie, a counting of chromosome number and the microsporogenesis analysis of A. triplinervia were done. The inflorescences were collected in the municipalities of Paranavaí and Diamante do Norte, State of Paraná, Brazil, and the slides were prepared by squashing technique and staining with 1% acetic carmine. The analysis were performed using an optical microscope and showed a chromosome number for the specie equal to 2n=8x=72. Irregularities in the chromosome segregation process were the main meiotic abnormalities, presenting typical polyploid behavior. Other irregularities were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Euphorbiaceae; Chromosome number; 2n gametes; Meiosis; Polyploid. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782012000600012 |
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| Pereira Sühsner,Claudia; Honfi,Ana I; Ferrucci,María S; Deginani,Norma. |
| El presente trabajo tuvo por objeto caracterizar cariológicamente las especies del género Passiflora L., subgénero Passiflora, del Distrito Félix Pérez Cardozo, Guairá, Paraguay. Por primera vez, se da a conocer el número cromosómico en meiosis 2n = 9II para P. alata Curtis y P. caerulea L. También, se confirma el número cromosómico de 2n = 9II para P. edulis Sims. El comportamiento meiótico en todas las especies estudiadas fue normal, con segregación regular de los cromosomas. La asociación cromosómica frecuentemente encontrada en diacinesis y metafase I fue de bivalentes. Las pocas irregularidades meióticas observadas consistieron en cromosomas rezagados en anafase I y fases asincrónicas en meiosis II, sin embargo, la viabilidad de polen es alta, entre... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Meiosis; Passiflora; Viabilidad del polen. |
| Ano: 2016 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932016000100004 |
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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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| 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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| Registros recuperados: 45 | |
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