Dissecting the sugarcane expressed sequence tag (SUCEST) database: unraveling flower-specific genes

Existem quase 260.000 clones independentes, seqüenciados a partir da extremidade 5', no banco de dados do SUCEST (Sugarcane Expressed Sequence Tag), os quais foram obtidos a partir de 37 bibliotecas de cDNA preparadas de diferentes tecidos. Este grande número de etiquetas de seqüências expressas (ESTs) fornece uma oportunidade, sem precedentes em plantas, de realizar um 'digital differential screening' em bibliotecas de cDNA selecionadas. Geralmente, a freqüência de um determinado EST está correlacionada ao acúmulo de transcritos nos tecidos dos quais as bibliotecas de cDNA foram construídas, e desta forma, é possível comparar o transcriptoma completo de diferentes tecidos, usando uma análise computacional de um banco de dados de ESTs. Em nossa pesquisa, analisamos os ESTs de cana-de-açúcar de acordo com sua expressäo tecidual e identificamos mais de 1.000 putativos genes específicos de flor. O fato de que usando esta técnica fomos capazes de identificar homólogos em cana-de-açúcar, de vários genes previamente descritos como específicos de pólen, sustenta este método de estimar especificidade tecidual. Além disto, ESTs com similaridade a genes específicos de órgäos reprodutivos foram revelados, como por exemplo, o gene que codifica uma proteína meiótica essencial para a montagem do complexo sinaptonêmico e sinapse normal. Esta abordagem também permitiu a identificaçäo de muitas seqüências anônimas, específicas de flor, que säo boas candidatas para novos genes envolvidos com a reproduçäo de plantas. Este trabalho descreve a análise dos níveis de expressäo gênica de 24 clusters de ESTs, durante o desenvolvimento floral, usando um 'northern blot digital' construído a partir da contagem direta dos ESTs das bibliotecas näo-normalizadas de cDNAs de cana-de-açúcar.

Inflammatory and anti-inflammatory effects of soybean agglutinin

Soybean agglutinin (SBA) lectin, a protein present in raw soybean meals, can bind to and be extensively endocytosed by intestinal epithelial cells, being nutritionally toxic for most animals. In the present study we show that SBA (5-200 mug/cavity) injected into different cavities of rats induced a typical inflammatory response characterized by dose-dependent exudation and neutrophil migration 4 h after injection. This effect was blocked by pretreatment with glucocorticoid (0.5 mg/kg) or by co-injection of N-acetyl-galactosamine (100 x [M] lectin), but not of other sugars (100 x [M] lectin), suggesting an inflamatory response related to the lectin activity. Neutrophil accumulation was not dependent on a direct effect of SBA on the macrophage population since the effect was not altered when the number of peritoneal cells was increased or decreased in vivo. On the other hand, SBA showed chemotactic activity for human neutrophils in vitro. A slight increase in mononuclear cells was observed 48 h after ip injection of SBA. Phenotypic analysis of these cells showed an increase in the CD4+/CD8- lymphocyte population that returned to control levels after 15 days, suggesting the development of an immune response. SBA-stimulated macrophages presented an increase in the expression of CD11/CD18 surface molecules and showed some characteristics of activated cells. After intravenous administration, SBA increased the number of circulating neutrophils and inhibited in a dose-dependent manner the neutrophil migration induced by ip injection of carrageenan into peritoneal cavities. The co-injection of N-acetyl-galactosamine or mannose, but not glucose or fucose, inhibited these effects. The data indicate that soybean lectin is able to induce a local inflammatory reaction but has anti-inflammatory effect when present in circulating blood.

Prevalence of anemia among school-children from Rio-Acima (State of Minas Gerais, Brazil): use of the standardized prevalence method and evaluation of iron deficiency

The prevalence of anemia and iron deficiency was investigated in 332 children aged 7 to 15 years, 156 (47 per cent) boys and 176 (53 per cent) girls enrolled in the schools of the municipality of Rio Acima, MG. Seventy-four children were white (22.3 per cent), 218 were mulatto (65.7 per cent), and 40 were black (12 per cent). Mean hemoglobin level was 12.75 ñ 0.75 g/ dl. Lower values were determined for black children (12.32 + 0.87 g/dl) compared to white (l2.76 ñ 0.99 g/dl) and mulatto (12.81 ñ 0.94 g/dl) children. The prevalence of anemia was 16.6 per cent when determined on the basis of the percentage of children with hemoglobin values lower than the 3rd percentile for age and sex (standard method), and 36.2 per cent when determined by the standardized prevalence method for the evaluation of the prevalence of malnutrition in populations. Depletion of iron reserves was 8.13 per cent for the population in general and 20 per cent for the anemic children. This low prevalence of iron deficiency may have been the result of the value adopted as the lower normal limit (10 ng/ml) for serum ferritin values. The small percentage of anemic children with iron depletion may also be justified by the standard of normality adopted for hemoglobin values which was originally elaborated for the white population of North America and Finland and therefore may be inadequate for the population studied here, of diverse racial composition.