The anticoagulant effect of leech saliva was traditionally employed in the treatment of diabetes mellitus complications such as peripheral vascular complications.This study was carried out to examine the effect of lee...The anticoagulant effect of leech saliva was traditionally employed in the treatment of diabetes mellitus complications such as peripheral vascular complications.This study was carried out to examine the effect of leech saliva extract(LSE)on blood glucose levels in alloxan-induced diabetic rats.First,LSE was collected from leeches which were fed on a phagostimulatory solution.Second,total protein concentration was estimated using the Bradford assay.Third,diabetic rats were injected subcutaneously(sc)with LSE at doses of 500 and 1 000μg·kg 1body weight(bw).Other diabetic rats were injected sc with insulin at doses of 10 and 20 U·kg 1bw.Another group was injected simultaneously with LSE(250μg·kg 1bw)and insulin(10 U·kg 1bw).Fasting blood glucose(FBG)concentrations were monitored during a study period of eight hours at regular intervals.Findings showed that both doses of LSE resulted in a significant and gradual decrease in FBG starting from 10%18%downfall after two hours of injection reaching the maximal reduction activity of 58%after eight hours.Remarkably,LSE was sufficient to bring the rats to a near norm-glycemic state.The high dose of insulin induced a severe hypoglycemic condition after 2 4 h of injection.The lower dose was able to decline FBG for 2 6 h in rats which became diabetic again after 8 h.On the other hand,the concurrent injection of low doses of LSE and insulin produced a hypoglycemic effect with all rats showing normal FBG levels.Taken together,these findings indicated that the subcutaneous injection of LSE of the medicinal Malaysian leech was able to provide better glycemic control compared with insulin.Moreover,the synergism between LSE and insulin suggests that LSE could be utilized as an adjuvant medication in order to reduce insulin dosage or to achieve better control of blood glucose.展开更多
Fine-root decomposition is a critical process regulating ecosystem carbon cycles and affecting nutrient cycling and soil fertility.However,whether interaction between warming and grazing affects fine-root decompositio...Fine-root decomposition is a critical process regulating ecosystem carbon cycles and affecting nutrient cycling and soil fertility.However,whether interaction between warming and grazing affects fine-root decomposition is still under-researched in natural grasslands.A two-factorial experiment with asymmetric warming(i.e.daytime vs.nighttime and growing season vs.nongrowing season)and moderate grazing(i.e.about average 50%forage utilization rate)was conducted to explore whether warming and grazing affect fine-root decomposition and loss of nutrients during a 2-year decomposition period in an alpine meadow on the Tibetan Plateau.Both warming and grazing facilitated carbon cycling through increase in fine-root decomposition,and influenced element cycling which varies among elements.The effects of warming and grazing on fine-root decomposition and loss of nutrients were additive.Both warming and grazing significantly increased cumulative percentage mass loss and total organic carbon loss of fine roots during the 2-year experiment.Only warming with grazing treatment reduced percentage nitrogen loss,whereas warming,regardless of grazing,decreased percentage phosphorus loss.Warming and grazing alone increased percentage loss of potassium,sodium,calcium and magnesium compared with control.There were no interactions between warming and grazing on fine-root decomposition and loss of nutrients.There was greater temperature sensitivity of decreased phosphorus loss than that of decreased nitrogen loss.Different temperature sensitivities of percentage loss of nutrients from fine-root decomposition would alter ratios of the available nutrients in soils,and may further affect ecosystem structure and functions in future warming.展开更多
基金supported by the grant(No.EDW B 10-0393)from Research-Management Centre,International Islamic University Malaysia
文摘The anticoagulant effect of leech saliva was traditionally employed in the treatment of diabetes mellitus complications such as peripheral vascular complications.This study was carried out to examine the effect of leech saliva extract(LSE)on blood glucose levels in alloxan-induced diabetic rats.First,LSE was collected from leeches which were fed on a phagostimulatory solution.Second,total protein concentration was estimated using the Bradford assay.Third,diabetic rats were injected subcutaneously(sc)with LSE at doses of 500 and 1 000μg·kg 1body weight(bw).Other diabetic rats were injected sc with insulin at doses of 10 and 20 U·kg 1bw.Another group was injected simultaneously with LSE(250μg·kg 1bw)and insulin(10 U·kg 1bw).Fasting blood glucose(FBG)concentrations were monitored during a study period of eight hours at regular intervals.Findings showed that both doses of LSE resulted in a significant and gradual decrease in FBG starting from 10%18%downfall after two hours of injection reaching the maximal reduction activity of 58%after eight hours.Remarkably,LSE was sufficient to bring the rats to a near norm-glycemic state.The high dose of insulin induced a severe hypoglycemic condition after 2 4 h of injection.The lower dose was able to decline FBG for 2 6 h in rats which became diabetic again after 8 h.On the other hand,the concurrent injection of low doses of LSE and insulin produced a hypoglycemic effect with all rats showing normal FBG levels.Taken together,these findings indicated that the subcutaneous injection of LSE of the medicinal Malaysian leech was able to provide better glycemic control compared with insulin.Moreover,the synergism between LSE and insulin suggests that LSE could be utilized as an adjuvant medication in order to reduce insulin dosage or to achieve better control of blood glucose.
基金This research was supported by grants from the National Natural Science Foundation of China(41731175,31770524 and 31872994)the Strategic Priority Research Program A of the Chinese Academy of Sciences(XDA20050101)+1 种基金the Joint Key Research Fund(U20A2005)under cooperative agreement between the National Natural Science Foundation of China(NSFC)and Tibet Autonomous Region(TAR)he Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0302 and 2019QZKK0608).
文摘Fine-root decomposition is a critical process regulating ecosystem carbon cycles and affecting nutrient cycling and soil fertility.However,whether interaction between warming and grazing affects fine-root decomposition is still under-researched in natural grasslands.A two-factorial experiment with asymmetric warming(i.e.daytime vs.nighttime and growing season vs.nongrowing season)and moderate grazing(i.e.about average 50%forage utilization rate)was conducted to explore whether warming and grazing affect fine-root decomposition and loss of nutrients during a 2-year decomposition period in an alpine meadow on the Tibetan Plateau.Both warming and grazing facilitated carbon cycling through increase in fine-root decomposition,and influenced element cycling which varies among elements.The effects of warming and grazing on fine-root decomposition and loss of nutrients were additive.Both warming and grazing significantly increased cumulative percentage mass loss and total organic carbon loss of fine roots during the 2-year experiment.Only warming with grazing treatment reduced percentage nitrogen loss,whereas warming,regardless of grazing,decreased percentage phosphorus loss.Warming and grazing alone increased percentage loss of potassium,sodium,calcium and magnesium compared with control.There were no interactions between warming and grazing on fine-root decomposition and loss of nutrients.There was greater temperature sensitivity of decreased phosphorus loss than that of decreased nitrogen loss.Different temperature sensitivities of percentage loss of nutrients from fine-root decomposition would alter ratios of the available nutrients in soils,and may further affect ecosystem structure and functions in future warming.
