Caracterização citogenética em Schlumbergera truncata (Haworth) Moran e Schlumbergera × buckleyi (T. Moore) Tjaden (Cactaceae)

O número cromossômico diplóide de Schlumbergera truncata e Schlumbergera x buckleyi, de indivíduos com diferentes tipos de coloração de pétalas, foi determinado usando-se pontas de raízes. A utilização de 8-hidroxiquinoleína 0,003 M à 36 °C por 3 horas possibilitou melhor separação cromossômica. Técnica de bandeamento C e de coloração Giemsa permitiram o estudo cariológico dessas espécies. O híbrido Schlumbergera × buckleyi (rósea) apresenta 2n = 22 cromossomos com fórmula cariotípica 16 M + 6 SM. Schlumbergera truncata, apresentando pétalas nas cores vermelha, branca e pink, possui 2n = 22 cromossomos, formulação cariotípica idêntica à de Schlumbergera × buckleyi, enquanto a planta com flores de coloração amarelada mostrou 2n = 34 cromossomos. A classificação cromossômica foi baseada no índice centromérico. Nas plantas que apresentam coloração vermelha, branca, pink e rósea nas pétalas, o melhor período de obtenção de metáfases corresponde ao período de florescimento. Schlumbergera truncata com flores amareladas apresenta dois picos anuais de divisão mitótica. Esses resultados dão suporte à um melhor entendimento da biologia no gênero Schlumbergera e auxiliam na classificação taxonômica nos casos onde apenas as características fenotípicas não são suficientemente confiáveis para a classificação das plantas no mesmo táxon.

Chromosomal aberrations induced by 5-azacytidine combined with VP-16 (etoposide) in CHO-K1 and XRS-5 cell lines

A cytogenetic study was carried out with 5-azacytidine (5-azaC) and etoposide (VP-16) in CHO-K1 and XRS-5 (mutant cells deficient for double-strand break rejoining) cell lines to verify the interaction effects of the drugs in terms of induction of chromosomal aberrations. 5-azaC is incorporated into DNA causing DNA hypomethylation, and VP-16 (inhibitor of topoisomerase 11 enzyme) is a potent clastogenic agent. Cells in exponential growth were treated with 5-azaC for I h, following incubation for 7 h, and posttreatment with VP16 for the last 3 h. In K1 cells, the combined treatments induced a significant reduction in the aberrations induced in the X and A (autosome) chromosomes, which are the main target for 5-azaC. However, in XRS-5 cells, the drug combination caused a significant increase in the aberrations induced in those chromosomes, but with a concomitant reduction in the randomly induced-aberrations. In addition, each cell line presented characteristic cell cycle kinetics; while the combined treatment induced an S-arrest in K1 cells, alterations in cell cycle progression were not found for XRS-5, although each drug alone caused a G2-arrest. The different cell responses presented by the cell lines may be explained on the basis of the evidence that alterations in chromatin structure caused by 5-aza-C probably occur to a different extent in K1 and XRS-5 cells, since the mutant cells present a typical hyper-condensed chromosome structure (especially the X- and A chromosomes), but, alternatively, 5-aza-C could induce reactivation of DNA repair genes in XRS-5 cells. Teratogenesis Carcinog. Mutagen. Suppl. 1:171-186, 2003. (C) 2003 Wiley-Liss, Inc.

Whole-genome analysis for backfat thickness in a tropically adapted, composite cattle breed from Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parthenogenetic activation of bovine oocytes using single and combined strontium, ionomycin and 6-dimethylaminopurine treatments

In vitro-matured (IVM) bovine oocytes were activated with single and combined treatments of strontium (S), ionomycin (1) and 6-DMAP (D). Using oocytes IVM for 26 h, we observed that activation altered cell cycle kinetics (faster progression, MIII arrest, or direct transition from MII to pronuclear stage) when compared to in vitro fertilization. The effect of oocyte age on early parthenogenesis was assessed in oocytes IVM for 22, 26 and 30 h. Better results in pronuclear development were obtained in treatments ISD (81.7%) at 22 h; D (66.7%), IS (63.3%), ID (73.3%) and ISD (76.7%) at 26 h; and D (86.7%), IS (85.0%) and ID (78.3%) at 30 h. Higher cleavage occurred on ISD (80.0%) at 22 h; ID (83.3%) and ISD (91.7%) at 26 h; and 1 (86.7%), IS (90.0%), ID (85.0%) and ISD (95.0%) at 30 h. More blastocysts were achieved in ID (25.0%) and ISD (18.3%) at 22h; and in ID at 26h (45.0%) and 30h (50.0%). We also observed that IS allowed higher haploid (77.4%) embryonic development, whilst ID was better for diploid (89.1%) development. It was concluded that association of S and D without I was not effective for blastocyst development; treatments using S were less influenced by oocyte age, but when S was associated with D there was a detrimental effect on aged oocytes; treatment ISD promoted higher activation and cleavage rates in young oocytes and ID protocol was the best for producing blastocysts.

Effect of Vitrification of Feline Ovarian Cortex on Follicular and Oocyte Quality and Competence

Cryopreservation of ovarian cortex has important implications in the preservation of fertility and biodiversity in animal species. Slow freezing of cat ovarian tissue resulted in the preservation of follicular morphology and in the follicular development after xenografting. Vitrification has been recently applied to ovarian tissues of different species, but no information is available on the effect of this method on feline ovarian cortex. Moreover, meiotic competence of fully grown oocytes isolated from cryopreserved tissue has not been reported. The aim of this study was to evaluate the effect of vitrification of feline ovarian cortex on follicular morphology and oocyte integrity, as well as meiotic competence. A total of 352 fragments (1.52 mm3) were obtained from ovarian cortical tissues: 176 were vitrified and 176 were used fresh as control. Histological evaluation of fresh and vitrified fragments showed intact follicles after cryopreservation procedures with no statistically significant destructive effect from primordial to antral follicles. After IVM, oocytes collected from vitrified ovarian fragment showed a higher proportion of gametes arrested at germinal vesicle (GV) stage compared to those isolated from fresh control tissue (33.8% vs 2.9%; p < 0.001). However, oocytes isolated from vitrified tissues were able to resume meiosis, albeit at lower rate than those collected from fresh tissues (39.8% vs 85.9%; p < 0.00001). Vitrification induced changes in the organization of cytoskeletal elements (actin microfilaments and microtubules) of oocytes, but significantly only for actin network (p < 0.001). Finally, chromatin configuration within the GV was not affected by the cryopreservation procedure. Our study demonstrated that vitrification preserves the integrity of ovarian follicles and that oocytes retrieved from cryopreserved tissue maintain the capability of resuming meiosis. To our knowledge, this has not previously been reported in the cat.

Effects of Hormonal Supplementation on Nuclear Maturation and Cortical Granules Distribution of Canine Oocytes During Various Reproductive Stages

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of sequence of insemination after simultaneous thawing of multiple semen straws on conception rate to timed AI in suckled multiparous Nelore cows

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Isolamento e caracterização ultraestrutural de folículos pré-antrais de vacas da raça Nelore (Bos taurus indicus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Assessment of field fertility and several in vitro sperm characteristics following the use of different Angus sires in a timed-AI program with suckled Nelore cows

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphologic and morphometric analysis of testis of Pseudis limellum (Cope, 1862) (Anura, Hylidae) during the reproductive cycle in the Pantanal, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Degenerative process and cell death in salivary glands of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae) semi-engorged female exposed to the acaricide permethrin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Correlação entre a citologia aspirativa por agulha fina e a histologia no diagnóstico de tumores mamários de cadelas

Foram estudados tumores de mama em cadelas, comparando o seu padrão citológico, obtido através da Citologia Aspirativa por Agulha Fina (CAAF), com os resultados da histopatologia. Num período de um ano, as cadelas trazidas ao Hospital Veterinário -- UNESP -- Câmpus de Jaboticabal foram submetidas a exérese cirúrgica dos tumores mamários. As amostras foram avaliadas de acordo com parâmetros estruturais utilizados nos tumores mamários humanos, como grau de atipia, critérios nucleares, padrão de cromatina e nucléolos, alta celularidade e pouca coesão intercelular. Utilizaram-se estes critérios para diferenciar tumores mamários benignos de malignos com 63% de diagnósticos concordantes, sensibilidade de 73% e especificidade de 83%. Nossos dados mostraram ter uma correlação positiva com o prognóstico, demonstrando que é possível reconhecer variáveis estruturais de malignidade na citopatologia para obter um diagnóstico precoce e um prognóstico seguro.

Effects of scrotal insulation in Nellore bulls (Bos taurus indicus) on seminal quality and its relationship with in vitro fertilizing ability

The objectives of this study were to assess the effects of induced testicular degeneration in Bos taurus indicus (Nellore) bulls on changes in seminal characteristics and fertilizing ability of sperm. Four Nellore bulls (30-36-month-old, 500-550 kg) with good seminal quality (> 80% motile and morphologically normal sperm) had serotal insulation applied for 5 d. Semen was collected by electroejaculation and cryopreserved at a the pre-insulation moment, and 7, 14, and 21 d after insulation was removed. Gross motility, vigor of sperm movement (1-5), acrosome integrity, sperm morphology (phase-contrast microscopy), nuclear vacuoles and abnormal chromatin (Feulgen-stain) were determined after sperm preparations for in vitro fertilization (IVF). Prior to IVF, sperm were separated using a Percoll gradient (45% and 90%). Normal sperm decreased (P < 0.05) 14 and 21 d after insulation was removed. on 14 and 21 d, the incidence of head defects (9.7 +/- 0.6 and 17.0 +/- 0.8, respectively; mean +/- S.E.M) was higher (P < 0.05) in agreement with the incidence of nuclear vauoles (14.0 +/- 5.0 and 12.3 +/- 2.3) and abnormal chromatin (24.4 +/- 7.2 and 30.8 +/- 2.8). Although the frequency of cleaved oocytes decreased only on 21 d (P < 0.05), blastocyst rates were lower (P < 0.05) than pre-insulation on 14 and 21 d. In regression analyses, only nuclear vacuoles, head defects and intact acrosome accounted for differences in cleavage (R(2) = 0.38, 0.48, and 0.30, respectively) and blastocyst rates (R(2) = 0.35, 0.37, and 0.44). Abnormal chromatin was associated only with blastocyst rates (R(2) = 0.35). In conclusion, blastocyst rate was more sensitive than cleavage rate and the assessment of nuclear integrity is recommended to predict the fertilizing ability of bull sperm. (c) 2008 Elsevier B.V. All rights reserved.

Cytogenetic characterization of F1, F2 and backcross hybrids of the Neotropical catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum (Pimelodidae, Siluriformes)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

First report of a B chromosome in a natural population of Astyanax altiparanae (Characiformes, Characidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)