Efeito de várias disponibilidades hídricas, atuando como pré-condicionamento fisiológico durante a germinação das sementes de milho, no desenvolvimento das plântulas

The present paper considers the possible effects of physiological pre-treatment during the beginning of corn seeds germination in environments variable as to water availability (0 to -12 atm ). Periods of defficiency followed by 5 days without hydric limitations were compared with a control that remained equally, without reservations as to the disposability of water during 5 days. Results indicated that hydric pre-treatment of seeds can, if property adapted in its details, provide some advantages in the development of the seedlings derived from them. Chemical fungicide treatment of the seeds, submmited to the hydric pre-treatment may not be beneficial to the seedlings; as indicated by, in some isolated cases, the production of abnormalities in the embryonic structures.O presente trabalho buscou estimar os eventuais efeitos de pré-condicionamento fisiológico promovidos, durante o início da germinação das sementes de milho, por ambientes variáveis quanto à disponibilidade de água (0 a -12 atm). Para tanto, os períodos de deficiência eram sucedidos por prazos fixos de 5 dias sem limitações hídricas e comparados com uma testemunha que permaneceu, igualmente, sem restrições quanto à disponibilidade de água durante 5 dias. Os resultados encontrados indicaram que a técnica de pré-condicionamento hídrico das sementes pode, se devidamente adaptada em seus detalhes, propiciar algumas vantagens no desenvolvimento das plântulas delas oriundas. Adicionalmente, o tratamento químico fungicida das sementes, submetidas a pré-condicionamento hídrico, pode não trazer os benefícios esperados às plântulas; há casos isolados, ligados a produção de anormalidades nas estruturas embrionárias, em que o seu efeito é prejudicial

Microencapsulated Starter Culture During Yoghurt Manufacturing, Effect on Technological Features

The potential of living cell microencapsulation in sustaining cells’ viability, functionality and targeted release in gastrointestinal tract is relatively well documented. Differently, the effects exerted by the capsules on cell metabolic activities during fermentation of a food matrix as well as on cell physiology are poorly addressed. This paper aimed at studying the effects of chitosan-alginate capsules (matrix and core-shell) on metabolic activities of Streptococcus thermophilus and probiotic Lactobacillus delbrueckii during milk fermentation for yoghurt production. This food system has been used to monitor growth, acidification kinetics and strain proteolytic activity. Bacterial viability has been monitored during yoghurt storage at 4 °C for 28 days and an in vitro digestion to evaluate the protective effect exerted by the capsules. Furthermore, production of volatile metabolites associated with starter culture activity was monitored by headspace solid-phase microextraction-GC/MS to explore possible influence of microenvironment on cell metabolism. Results indicate that both kinds of capsules influenced at different extent cell functionalities (growth, acidification and proteolysis), while they improve cell viability during yoghurt storage and simulated gastrointestinal passage. The volatile pattern revealed that capsules influenced their production in yoghurt: 12 out of 28 volatiles recovered in yoghurt fermented by free and encapsulated starters had significantly different concentration. However, concentration of the main aroma constituents (e.g. acetaldehyde, diacetyl, acetoin) was not significantly affected. Due to the leakage of bacteria from microcapsules during fermentation, the final product resulted in co-existing of free and still encapsulated cells, with the main advantage of an increased viability during yoghurt storage and simulated digestion of the encapsulated counterpart.</p

Effect of erythropoietin therapy and withdrawal on blood coagulation and fibrinolysis in hemodialysis patients

Effect of erythropoietin therapy and withdrawal on blood coagulation and fibrinolysis in hemodialysis patients. Erythropoietin (EPO) therapy in hemodialysis patients may be associated with an enhanced risk of vascular access and extracorporeal thrombosis. Assessment of blood coagulation and fibrinolysis was performed monthly on a group of 21 hemodialysis patients treated with EPO, and on four iron-deficient hemodialysis patients treated with iron dextran infusions alone. Seventeen of the EPO treated patients were also monitored after withdrawal of EPO to allow hemoglobin to fall to pre-EPO levels, and 16 of these patients during a second subsequent phase of EPO therapy with EPO administered using the alternative route (subcutaneous/intravenous) from the first phase of treatment. Ten untreated hemodialysis patients with intrinsically high hemoglobins were studied as controls. EPO was associated with significant increases in the endothelial product Factor VIII von Willebrand factor antigen (FVIIIvWFAg), and plasma fibrinogen, to levels comparable to those observed in the untreated control patients. Both FVIIIvWFAg and fibrinogen remained significantly elevated when EPO was withdrawn. Whole blood platelet aggregation (spontaneous, collagen, and ADP-induced) also increased following EPO, collagen and ADP-induced aggregation, increasing further when EPO was withdrawn. Transient but significant changes occurred in plasma measures of thrombin-antithrombin III complex, prostacyclin stimulating factor, and protein C during the first EPO treatment phase, and also thrombin-antithrombin III complex during the second treatment phase, all favoring a tendency to thrombosis. D-dimer increased significantly following EPO withdrawal. Erythrocyte deformability, and granulocyte aggregation did not change. There was no effect of route of EPO administration (subcutaneous or intravenous) or EPO dose on any of these parameters. The iron dextran treated patients had increased platelet aggregation and tissue plasminogen activator antigen in association with a smaller increment in hemoglobin. In conclusion, EPO may be associated with changes in blood coagulation and fibrinolysis: (a) transiently, during the initial months of therapy, (b) after correction of anemia, and (c) following EPO withdrawal. Some of these changes could influence the risk of thrombosis during EPO therapy

Novel indices reveal that pollinator exposure to pesticides varies across biological compartments and crop surroundings

International audienceDeclines in insect pollinators have been linked to a range of causative factors such as disease, loss of habitats, the quality and availability of food, and exposure to pesticides. Here, we analysed an extensive dataset generated from pesticide screening of foraging insects, pollen-nectar stores/beebread, pollen and ingested nectar across three species of bees collected at 128 European sites set in two types of crop. In this paper, we aimed to (i) derive a new index to summarise key aspects of complex pesticide exposure data and (ii) understand the links between pesticide exposures depicted by the different matrices, bee species and apple orchards versus oilseed rape crops. We found that summary indices were highly correlated with the number of pesticides detected in the related matrix but not with which pesticides were present. Matrices collected from apple orchards generally contained a higher number of pesticides (7.6 pesticides per site) than matrices from sites collected from oilseed rape crops (3.5 pesticides), with fungicides being highly represented in apple crops. A greater number of pesticides were found in pollen-nectar stores/beebread and pollen matrices compared with nectar and bee body matrices. Our results show that for a complete assessment of pollinator pesticide exposure, it is necessary to consider several different exposure routes and multiple species of bees across different agricultural systems

Metodologia para germinação de sementes de Leonurus sibiricus L Methodology for Leonurus sibiricus L. seed germination

O objetivo do trabalho foi investigar a influência de diferentes temperaturas, o comportamento fotoblástico e a absorção de água de sementes de Leonurus sibiricus L. Essa espécie medicinal é originária da Índia, distribuída pela Ásia, África e América, utilizada no tratamento de reumatismo, problemas dermatológicos e respiratórios. Para tanto, as sementes foram submetidas a temperaturas entre 5 a 40ºC, com intervalos de 5ºC, e alternadas de 20/30, 20/25 e 25/30ºC, com 5 repetições de 50 sementes cada, em condições de luz e escuro. No estudo da absorção de água as sementes foram colocadas para germinar na temperatura de 20ºC e na presença da luz e pesadas para avaliar o ganho de água durante todo o processo germinativo, até a protrusão da radícula. Pelos resultados verificou-se que os maiores porcentuais de germinação e índice de velocidade de germinação ocorreram na temperatura constante de 20ºC, e nas temperaturas alternadas 20/25, 25/30, 25/30ºC sob luz. Houve germinação na temperatura mínima de 10ºC e na máxima 40ºC. No ensaio de absorção de água verificou-se que as sementes iniciam a protrusão da radícula com 65 horas de exposição e seguem padrão trifásico na curva de absorção. O modelo estatístico ajustado para a espécie foi y = 1,869 (1 - 0,414 exp ( -0,201t) + exp [-2,397 + 0,037 (t - 65)], com R²= 0,9998.<br>The aim of this study was to investigate the influence of different temperatures on the photoblastic response and water uptake of Leonurus sibiricus L. seeds. This medicinal species is from India and has been distributed over Asia, Africa and America, where it is used in the treatment of rheumatic, dermatological and respiratory disorders. Thus, seeds were subjected to temperatures between 5 and 40ºC, at 5ºC intervals, and 20/30, 20/25 and 25/30ºC alternate temperatures, with five replicates of 50 seeds each, under light and dark conditions. In the study of water uptake, seeds were allowed to germinate at 20ºC under light and weighed throughout the germinative process until radicle protrusion. The highest germination percentage and speed index were detected at 20ºC constant temperature and at 20/25, 25/30 and 25/30ºC alternate temperatures under light. There was germination at 10ºC (minimum temperature) and at 40ºC (maximum temperature). The study on water uptake showed that seeds began radicle protrusion at 65h exposure and follow the triphasic pattern in the uptake curve. The statistical model fit for the species was y = 1.869 (1 - 0.414 exp (-0.201 t) + exp [-2.397 + 0.037 (t - 65)], R² = 0.9998