RESUMO
Plant Dicer-like (DCL) and Argonaute (AGO) are the key enzymes involved in anti-virus post-transcriptional gene silencing (AV-PTGS). Here we show that AV-PTGS exhibited nucleotide preference by calculating a relative AV-PTGS efficiency on processing viral RNA substrates. In comparison with genome sequences of dicot-infecting Turnip mosaic virus (TuMV) and monocot-infecting Cocksfoot streak virus (CSV), viral-derived small interfering RNAs (vsiRNAs) displayed positive correlations between AV-PTGS efficiency and G+C content (GC%). Further investigations on nucleotide contents revealed that the vsiRNA populations had G-biases. This finding was further supported by our analyses of previously reported vsiRNA populations in diverse plant-virus associations, and AGO associated Arabidopsis endogenous siRNA populations, indicating that plant AGOs operated with G-preference. We further propose a hypothesis that AV-PTGS imposes selection pressure(s) on the evolution of plant viruses. This hypothesis was supported when potyvirus genomes were analysed for evidence of GC elimination, suggesting that plant virus evolution to have low GC% genomes would have a unique function, which is to reduce the host AV-PTGS attack during infections.
Assuntos
Arabidopsis , Genética , Virologia , Composição de Bases , Dactylis , Genética , Virologia , Genes de Plantas , Genes Virais , Modelos Genéticos , Mostardeira , Genética , Virologia , Doenças das Plantas , Genética , Virologia , Proteínas de Plantas , Metabolismo , Vírus de Plantas , Genética , Virulência , Plantas , Genética , Virologia , Potyvirus , Genética , Virulência , Interferência de RNA , RNA de Plantas , Genética , RNA Interferente Pequeno , Química , Genética , Metabolismo , RNA Viral , Química , Genética , Metabolismo , Complexo de Inativação Induzido por RNA , Metabolismo , Ribonuclease III , Metabolismo , Seleção Genética , Especificidade por SubstratoRESUMO
Background: Cardiopulmonary bypass (CPB) may reduce the numbers of platelets and cause platelet function disorder. Postoperative bleeding is one of the most common complications in patients undergoing cardiac surgery. Objectives: (1) To study changes platelet count and platelet aggregation with ADP in patients undergoing CPB. (2) To identify the relationship between the postoperative bleeding and these parameters. Subjects and method: Crossectional descriptive study on 35 patients of three groups: congenital heart diseases, valvular heart diseases and coronary artery disease. Results: Platelet count and platelet aggregation with ADP reduce. Conclusion: There is a considerably change in the number of platelets and disturbance of platelet function in patients undergoing CPB. No remarkable evidence on relationship between posttoperative bleeding and above disorders.
Assuntos
Agregação Plaquetária , Ponte CardiopulmonarRESUMO
Background: Cardiac surgery with cardiopulmonary bypass (CPB) can cause haemostatic abnormalities that increase the risk of postoperative hemorrhage. Objectives: (1) To study changes of coagulation in cardiac patients undergoing surgery with CPB. (2) To research the relationship between duration of cardiopulmonary bypass, coagulation tests and postoperative hemorrhage complications. Subjects and methods: A cross sectional descriptive study was carried out on 252 patients (105 women, 147 men) undergoing cardiac surgery with CPB due to congenital heart disease and acquired heart disease at Viet Duc Hospital from December 2005 to August 2006. Results: After surgery, 54 patients had to transfuse the blood products, accounting for 21.4% rate. 21 cases had abnormal bleeding (8.3%). 12 patients assigned to re-operate due to bleeding (4.8%). There was an inverse correlation between platelet counts after surgery with duration of CPB and duration of aortic clamping. Relationship between rate of prothrombin, APTT, fibrinogen after surgery and duration of CPB and duration of aortic clamping was not seen. Duration of CPB prolonging over 120 minutes related to postoperative hemorrhage complication (OR=2.69 (p<0.5)). Reduced platelet count increased the risk of postoperative hemorrhage but not statistically significant (OR=1.36; p>0.05). Prothrombin ratio of less than 50% associated with the risk of postoperative hemorrhage (OR=4.83; p<0.01). Conclusion: The routine coagulation tests can help monitor clotting in patients after cardiac surgery
Assuntos
Hemorragia , Terapêutica , Ponte CardiopulmonarRESUMO
Knowledge, attitude and behaviour for HIV/AIDS in pupils of the high school in Luong Son district, Hoa Binh province