RESUMEN
Organic acids metabolism and nitrogen (N) metabolism in rice seedlings and the relationship between them are not fully understood. In this study, rice (Oryza sativa L. ssp. Indica) variety "Huanghuazhan" was used as the experimental material, and three N levels (5 mM, 1 mM, and 0 mM NH4NO3) were set by the hydroponic method for different levels of N treatment. Our results showed that the increased content of malate in rice leaves caused by reducing N level was related to the increased synthesis of malate (the activity of leaf PEPC increased)and the decreased degradation of malate (the activity of leaf NADP-ME decreased), while the increased contents of citrate and isocitrate in rice leaves caused by reducing N level might not be caused by the increased biosynthesis, but due to the decrease in degradation of citrate and isocitrate (the activities of leaf CS, ACO, and NADP-IDH decreased). The increased content of malate in rice roots caused by reducing N level might be related to the increased biosynthesis and the decreased degradation of root malate (the activities of root NAD-MDH and PEPC increased, while the activity of NADP-ME decreased). Compared to the control (5 mM NH4NO3), the increased content of citrate in rice roots caused by reducing N level might be related to the increased biosynthesis rather than the decreased degradation of citrate, due to the higher activities of CS and ACO in rice roots under 0 mM N and 1mM N treatment when compared to that of the control ones. At the same time, the increased content of isocitrate in roots was related to the increased isomerization of isocitrate (the activity of root ACO increased) and the decreased degradation of isocitrate (the activity of root NADP-IDH decreased). With the reducing N level, the activities of N metabolism-related enzymes, such as nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT), decreased in rice leaves and roots, resulting in the decreased contents of total free amino acids (TFAAs) and soluble proteins in rice seedlings, and finally led to the growth inhibition. Our results showed that the dynamics of organic acids metabolism caused by reducing N level were different in rice leaves and roots. In conclusion, there was a close correlation between organic acids metabolism and N metabolism in rice leaves and roots under N-limited conditions; furthermore, such a correlation was more obvious in rice leaves than that of roots.
RESUMEN
OBJECTIVE: To summarize the experience in laparoscopic resection of true pancreatic cyst. METHODS: Five patients with true pancreatic cyst, including 1 case of pancreatic head cyst and 4 cases of distal pancreatic cyst, underwent laparoscopic resection. Among them one case with pancreatic head cyst and 4 cases of distal pancreatic cyst underwent simple laparoscopic cyst resection and one case of distal pancreatic cyst underwent laparoscopic distal pancreatectomy with resection of the spleen. The curative effects were evaluated. A follow-up lasting 2 approximately 33 months was conducted. RESULTS: All operations were successful with intraoperative blood loss of 50 to 150 ml. The patients could get up and move about 6 hours after the operation and were recovered and discharged 4 to 6 days later. Follow-up showed that all symptoms disappeared and no recurrence of cyst occurred. CONCLUSION: Laparoscopic resection of true pancreatic cyst is feasible with the advantages of reduced injury and earlier recovery.
