Morphological differences in human zygotes and embryos cultured in different media.

PURPOSE: To compare the effects of four culture media on the quality of human zygotes and embryos. METHODS: Prospective study analyzing 2289 human embryos cultivated simultaneously in two different culture media: HTF, the default medium, with either Universal IVF, Global or IVF-30 as the secondary media. The sibling oocytes by each patient were randomly divided between the two culture media following intracytoplasmic sperm injection (ICSI). On day 1 the pronuclear stage of zygotes were evaluated and on day 2 embryos were evaluated according to the number of cells, percentage of fragmentation and number of nuclei. Z-test and odds ratios were used in the statistical analysis. RESULTS: There was a higher percentage (55.2%) of class A1 + A2 zygotes with IVF-30 compared with HTF, Global or Universal IVF media (49.1%, 44.7% and 44.2%, respectively). The percentage of Top embryos was significantly higher with Global (40.2%) compared with HTF (21.3%), IVF-30 (25.0%) or Universal IVF media (11.2%). CONCLUSIONS: Global medium produced more Top embryos evaluated on day 2 of development.

Over-expression of a tomato N-acetyl-L-glutamate synthase gene (SlNAGS1) in Arabidopsis thaliana results in high ornithine levels and increased tolerance in salt and drought stresses.

A single copy of the N-acetyl-L-glutamate synthase gene (SlNAGS1) has been isolated from tomato. The deduced amino acid sequence consists of 604 amino acids and shows a high level of similarity to the predicted Arabidopsis NAGS1 and NAGS2 proteins. Furthermore, the N-terminus ArgB domain and the C-terminus ArgA domain found in SlNAGS1 are similar to the structural arrangements that have been reported for other predicted NAGS proteins. SlNAGS1 was expressed at high levels in all aerial organs, and at basic levels in seeds, whereas it was not detected at all in roots. SlNAGS1 transcript accumulation was noticed transiently in tomato fruit at the red-fruit stage. In addition, an increase of SlNAGS1 transcripts was detected in mature green tomato fruit within the first hour of exposure to low oxygen concentrations. Transgenic Arabidopsis plants have been generated expressing the SlNAGS1 gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Three homozygous transgenic lines expressing the transgene (lines 1-7, 3-8, and 6-5) were evaluated further. All three transgenic lines showed a significant accumulation of ornithine in the leaves with line 3-8 exhibiting the highest concentration. The same lines demonstrated higher germination ability compared to wild-type (WT) plants when subjected to 250 mM NaCl. Similarly, mature plants of all three transgenic lines displayed a higher tolerance to salt and drought stress compared to WT plants. Under most experimental conditions, transgenic line 3-8 performed best, while the responses obtained from lines 1-7 and 6-5 depended on the applied stimulus. To our knowledge, this is the first plant NAGS gene to be isolated, characterized, and genetically modified.

Associação entre morfologia do ovócito e taxa de fertilização após ICSI / Relationship between oocyte morphology and fertilization rate after ICSI

OBJETIVO: verificar a possibilidade de selecionar ovócitos que resultariam em maior taxa de fertilização. MÉTODOS: estudo retrospectivo que analisou a taxa de fertilização após ICSI de 957 ovócitos em metáfase II segundo três parâmetros da morfologia ovocitária: granulações citoplasmáticas, espaço perivitelino e fragmentação do primeiro corpúsculo polar. Os ovócitos foram obtidos de 115 ciclos realizados em 107 mulheres atendidas no CRHC, entre abril e dezembro de 2004. Para a análise estatística das diferenças na taxa de fertilização entre ovócitos "normais" e os que apresentavam cada alteração, utilizou-se o teste de chi2, com nível de confiança de 5 e 10 por cento. RESULTADOS: não se observou diferença significativa na taxa de fertilização segundo as características do corpúsculo polar ou espessura do espaço perivitelino. A taxa de fertilização dos ovócitos com espaço perivitelino apresentando debris foi quase 14 pontos percentuais inferior ao dos ovócitos com espaço "ausente" (p=0,055) e a dos ovócitos com citoplasma granular foi sete pontos percentuais inferior à obtida pelos ovócitos com citoplasma de aspecto normal (p<0,10>0,05). CONCLUSÕES: os parâmetros da morfologia do ovócito atualmente utilizados não permitem distinguir claramente aqueles que serão fertilizados dos que não serão.

PURPOSE: to verify the possibility of identifying oocytes that would result in a higher fertilization rate. METHODS: retrospective analysis of the fertilization rate after ICSI of 957 oocytes in metaphase II according to three morphology parameters: cytoplasm inclusions, thickness of the perivitelline space, and fragmentation of the first polar body. Oocytes were obtained from 115 cycles performed among 107 women attended at the "Centro de Reprodução Humana de Campinas", from April to December of 2004. For the statistical analysis of differences in the fertilization rate between 'normal' oocytes and those presenting each alteration, the chi2 test was used with confidence levels of 5 and 10 percent. RESULTS: no significant difference in fertilization rate was observed regarding characteristics of the polar body or thickness of the perivitelline space. Fertilization rate among oocytes with perivitelline space with debris was 14 percentage points lower than among oocytes with absent space (p=0.055) and the rate among oocytes with granular cytoplasm was seven percentage points lower than among oocytes with normal cytoplasm (p<0.10>0.05). CONCLUSIONS: the morphological parameters of oocytes currently being evaluated do not allow us to clearly distinguish those that would lead to a higher fertilization rate and could be used in clinical practice.