Testes de deterioração controlada e envelhecimento acelerado em sementes de soja.

São considerados eficientes os testes que permitem separar lotes de sementes em diferentes categorias de vigor, quando possuem germinação semelhante. Os testes de deterioração controlada e envelhecimento acelerado têm como princípio a aceleração do processo de deterioração. Neste experimento, conduzido com cinco lotes de sementes de soja da cultivar M 8866, o objetivo foi comparar os testes de deterioração controlada, envelhecimento acelerado e envelhecimento acelerado com teor de água ajustado, para avaliar o vigor desses lotes e verificar o desempenho na emergência a campo. Foi determinado o teor de água dos lotes, pelo método da estufa 105 °C ± 3 °C por 24 horas, em seguida, foi realizado o ajuste de umidade para 23%. Após 49 horas, os lotes atingiram o teor de água de 23%, e as amostras foram pesadas e colocadas em saco de plástico vedado e levados a 10 °C por 24 horas para equilíbrio de umidade. As subamostras com teor de água ajustado e sem ajuste foram submetidas ao envelhecimento acelerado a 41 °C por 48 horas e depois semeadas e colocadas em BOD a 25 °C, com leitura aos cinco dias após semeadura. Para a deterioração controlada as subamostras com teor de água ajustado foram colocadas em banho maria a 41 °C por 24 horas e depois foram semeadas e colocadas em BOD a 25 °C, com leitura aos cinco dias. O teste de envelhecimento acelerado com ajuste do teor de água foi mais eficiente para avaliar o desempenho dos lotes de sementes de soja comparados com emergência em campo. O teste de deterioração controlada em banho maria foi semelhante ao teste de envelhecimento acelerado para avaliar o vigor dos lotes de sementes de soja, separando em três níveis de vigor

Glycosylation with O-linked β-N-acetylglucosamine (O-GlcNAc) induces vascular dysfunction via production of superoxide anion/reactive oxygen species

Overproduction of superoxide anion (•O2-) and O-linked β-N-acetylglucosamine (O-GlcNAc)-modification in the vascular system are contributors to endothelial dysfunction. This study tested the hypothesis that increased levels of O-GlcNAc-modified proteins contribute to •O2- production via activation of NADPH oxidase, resulting in impaired vasodilation. Rat aortic segments and vascular smooth muscle cell (VSMCs) were incubated with vehicle (methanol) or PUGNAc (100 µM). PUGNAc produced a time-dependent increase in O-GlcNAc levels in VSMC and decreased endothelium-dependent relaxation, which was prevented by apocynin and Tiron, suggesting that •O2- contributes to endothelial dysfunction under augmented O-GlcNAc levels. Aortic segments incubated with PUGNAc also exhibited increased levels of ROS, assessed by dihydroethidium fluorescence, and augmented •O2- production, determined by lucigenin-enhanced chemiluminescence. Additionally, PUGNAc treatment increased Nox1 and Nox4 protein expression in aorta and VSMCs. Translocation of p47phox subunit from the cytosol to the membrane was greater in aortas incubated with PUGNAc. VSMCs displayed increased p22phox protein expression after PUGNAc incubation, suggesting that NADPH oxidase is activated in conditions where O-GlcNAc protein levels are increased. In conclusion, O-GlcNAc levels reduce endothelium-dependent relaxation by overproduction of •O2- via activation of NADPH oxidase. This may represent an additional mechanism by which augmented O-GlcNAc levels impair vascular function

Potencial de armazenamento de sementes de soja transgênica X convencional.

A soja Roundup Ready (RR) foi a primeira planta transgênica a ser aprovada para alimentação humana e animal para cultivo no Brasil. No caso da soja resistente ao glyphosate, a tolerância ao herbicida foi obtida pela inserção de um gene oriundo do genoma da Agrobacterium sp. Sob tratamento com esse herbicida, as plantas de soja não são afetadas, em virtude da ação continuada e sistemática dessa enzima alternativa, insensível ao produto. Porém, há relatos de decréscimo no potencial de armazenamento de sementes de soja transgênica, quando comparadas às convencionais. Neste trabalho o objetivo foi avaliar o potencial de armazenamento de sementes de variedades de soja transgênica (RR), comparativo a suas isolinhas não geneticamente modificadas. O potencial fisiológico (germinação e vigor - envelhecimento acelerado e emergência em areia) das variedades transgênicas foi analisado comparativamente com suas isolinhas em quatro períodos de armazenamento, com quatro repetições cada teste. As avaliações foram realizadas a cada dois meses. As variedades testadas foram BRS Valiosa RR e sua isolinha BR 46 Conquista; BRS 255 RR e BRS 137; BRS 245 RR e BRS 133. As variedades foram semeadas na mesma época e local, com o mesmo manejo cultural. Foi realizada capina manual, a colheita foi realizada em R7 e as plantas foram colocadas para secar a sombra. Após secas as vagens foram debulhadas manualmente. As sementes foram armazenadas em câmara refrigerada à temperatura de 18 ºC ± 2 ºC e 75% ± 4% de umidade relativa, até o momento da instalação dos experimentos. Não ocorreram variações nos potenciais de armazenamento entre as variedades transgênicas e suas isolinhas não geneticamente modificadas. O decréscimo do potencial fisiológico das sementes durante o armazenamento foi em função do qualidade inicial independente da variedade

TSPY1 copy number variation influences spermatogenesis and shows differences among Y lineages.

CONTEXT: TSPY1 is a tandemly-repeated gene on the human Y chromosome forming an array of approximately 21–35 copies. The testicular expression pattern and the inferred function of the TSPY1 protein suggest possible involvement in spermatogenesis. However, data are scarce on TSPY1 copy number variation in different Y lineages and its role in spermatogenesis. OBJECTIVES: We sought to define: 1) the extent of TSPY1 copy number variation within and among Y chromosome haplogroups; and 2) the role of TSPY1 dosage in spermatogenic efficiency. MATERIALS AND METHODS: A total of 154 idiopathic infertile men and 130 normozoospermic controls from Central Italy were analyzed. We used a quantitative PCR assay to measure TSPY1 copy number and also defined Y haplogroups in all subjects. RESULTS: We provide evidence that TSPY1 copy number shows substantial variation among Y haplogroups and thus that population stratification does represent a potential bias in case-control association studies. We also found: 1) a significant positive correlation between TSPY1 copy number and sperm count (P < 0.001); 2) a significant difference in mean TSPY1 copy number between patients and controls (28.4 ± 8.3 vs. 33.9 ± 10.7; P < 0.001); and 3) a 1.5-fold increased risk of abnormal sperm parameters in men with less than 33 copies (P < 0.001). CONCLUSIONS: TSPY copy number variation significantly influences spermatogenic efficiency. Low TSPY1 copy number is a new risk factor for male infertility with potential clinical consequences

Phenotypic variation within European carriers of the Y-chromosomal gr/gr deletion is independent of Y-chromosomal background.

BackgroundPrevious studies have compared sperm phenotypes between men with partial [1] deletions within the AZFc region of the Y chromosome with non-carriers, with variable results. Here, we have investigated a separate question, the basis of the variation in sperm phenotype within gr/gr deletion carriers, which ranges from normozoospermia to azoospermia. Differences in the genes removed by independent gr/gr deletions, the occurrence of subsequent duplications or the presence of linked modifying variants elsewhere on the chromosome have been suggested as possible causal factors. We set out to test these possibilities in a large sample of gr/gr deletion carriers with known phenotypes spanning the complete range.ResultsWe assembled a collection of 169 men diagnosed with gr/gr deletions from six centres in Europe and one in Australia, and characterized the DAZ and CDY1 copies retained, the presence or absence of duplications and the Y-chromosomal haplogroup. Although our study had good power to detect factors that accounted for 655.5% of the variation in sperm concentration, no such factor was detected. A negative effect of gr/gr deletions followed by b2/b4 duplication was observed within the normospermic group, which remains to be further explored in a larger study population. Finally, we observed significant geographical differences in the frequency of different subtypes of gr/gr deletions which may have relevance for the interpretation of case control studies dealing with admixed populations.ConclusionsWe conclude that the phenotypic variation of gr/gr carriers in men of European origin is largely independent of the Y-chromosomal background

STIM1/Orai1 contributes to sex differences in vascular responses to calcium in spontaneously hypertensive rats. Clin. Sci. (Lond

Sex differences in Ca 2 + -dependent signalling and homoeostasis in the vasculature of hypertensive rats are well characterized. However, sex-related differences in SOCE (store-operated Ca 2 + entry) have been minimally investigated. We hypothesized that vascular protection in females, compared with males, reflects decreased Ca 2 + mobilization due to diminished activation of Orai1/STIM1 (stromal interaction molecule 1). In addition, we investigated whether ovariectomy in females affects the activation of the Orai1/STIM1 pathway. Endothelium-denuded aortic rings from male and female SHRSP (stroke-prone spontaneously hypertensive rats) and WKY (Wistar-Kyoto) rats and from OVX (ovariectomized) or sham female SHRSP and WKY rats were used to functionally evaluate Ca 2 + influx-induced contractions. Compared with females, aorta from male SHRSP displayed: (i) increased contraction during the Ca 2 + -loading period; (ii) similar transient contraction during Ca 2 + release from the intracellular stores; (iii) increased activation of STIM1 and Orai1, as shown by the blockade of STIM1 and Orai1 with neutralizing antibodies, which reversed the sex differences in contraction during the Ca 2 + -loading period; and (iv) increased expression of STIM1 and Orai1. Additionally, we found that aortas from OVX-SHRSP showed increased contraction during the Ca 2 + -loading period and increased Orai1 expression, but no changes in the SR (sarcoplasmic reticulum)-buffering capacity or STIM1 expression. These findings suggest that augmented activation of STIM1/Orai1 in aortas from male SHRSP represents a mechanism that contributes to sex-related impaired control of intracellular Ca 2 + levels. Furthermore, female sex hormones may negatively modulate the STIM/Orai1 pathway, contributing to vascular protection observed in female rats