A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed ...A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.展开更多
Chronic pollution in aquatic ecosystems can lead to many adverse effects,including a greater susceptibility to pathogens among resident biota.Trifloxystrobin(TFS)is a strobilurin fungicide widely used in Asia to contr...Chronic pollution in aquatic ecosystems can lead to many adverse effects,including a greater susceptibility to pathogens among resident biota.Trifloxystrobin(TFS)is a strobilurin fungicide widely used in Asia to control soybean rust.However,it has the potential to enter aquatic ecosystems,where it may impair fish resistance to viral infections.To explore the potential environmental risks of TFS,we characterized the antiviral capacities of fish chronically exposed to TFS and subsequently infected with spring viraemia of carp virus(SVCV).Although TFS exhibited no significant cytotoxicity at the tested environmental concentrations during viral challenge,SVCV replication increased significantly in a time-dependent manner within epithelioma papulosum cyprini(EPC)cells and zebrafish exposed to 25μg/L TFS.Results showed that the highest viral load was more than 100-fold that of the controls.Intracellular biochemical assays indicated that autophagy was induced by TFS,and associated changes included an increase in autophagosomes,conversion of LC3-II,accumulation of Beclin-1,and degradation of P62 in EPC cells and zebrafish.In addition,TFS markedly decreased the expression and phosphorylation of mTOR,indicating that activation of TFS may be associated with the mTORmediated autophagy pathway.This study provides new insights into the mechanism of the immunosuppressive effects of TFS on non-target aquatic hosts and suggests that the existence of TFS in aquatic environments may contribute to outbreaks of viral diseases.展开更多
[ Objective] The paper was to confirm the best application period and frequency of 75% trifloxystrobin ·tebuconazole WG against rice blast and rice sheath blight. [ Method] Influences of different dosages and dif...[ Objective] The paper was to confirm the best application period and frequency of 75% trifloxystrobin ·tebuconazole WG against rice blast and rice sheath blight. [ Method] Influences of different dosages and different application periods of 75% trifloxystrobin · tebuconazole WG on control effects against rice blast and rice sheath blight, as well as their effects on rice yields were studied in the paper. [Result] The control effects of three different fungicides application treatments against rice sheath blight were 80.24%, 83.0% and 67.99%, and the control effects against rice blast were 56.4%, 49.11% and 61.1%, respective- ly. Advanced application of fungicide for two times had good prevention effect against rice sheath blight ; properly delayed application of fungicides for two times was conducive to improving the control effect against rice blast, and one time application of sufficient fungicide during middle booting stage had higher control effect than application for two times. Effective panicle number per unit area, total grain number, 1 000-grain weight and moisture content of various fungicide application treat- ments did not have significant difference with those of the treatments without fungicide application, but grain number per panicle in treatments applied with fungicide was higher than the treatment without application. [ Conclusion] 75% Trifloxystrobin ·tebuconazole WG has better control effect on rice blast and sheath blight, which helps to promote the formation of rice grain and increases yield significantly. The fungicide application against rice sheath blight should be appropriately ad- vanced, and application for one time against panicle blast after middle booting stage is helpful to improve the control effect.展开更多
基金Project supported by the National Tea Research Foundation, Kolkata,India
文摘A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.
基金This work was supported by the National Natural Science Foundation of China(31902410)Program of State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products(KF20200106)+1 种基金Natural Science Foundation of Zhejiang Province(LY21C190002)Foundation of Ningbo City of China(202003N4120)。
文摘Chronic pollution in aquatic ecosystems can lead to many adverse effects,including a greater susceptibility to pathogens among resident biota.Trifloxystrobin(TFS)is a strobilurin fungicide widely used in Asia to control soybean rust.However,it has the potential to enter aquatic ecosystems,where it may impair fish resistance to viral infections.To explore the potential environmental risks of TFS,we characterized the antiviral capacities of fish chronically exposed to TFS and subsequently infected with spring viraemia of carp virus(SVCV).Although TFS exhibited no significant cytotoxicity at the tested environmental concentrations during viral challenge,SVCV replication increased significantly in a time-dependent manner within epithelioma papulosum cyprini(EPC)cells and zebrafish exposed to 25μg/L TFS.Results showed that the highest viral load was more than 100-fold that of the controls.Intracellular biochemical assays indicated that autophagy was induced by TFS,and associated changes included an increase in autophagosomes,conversion of LC3-II,accumulation of Beclin-1,and degradation of P62 in EPC cells and zebrafish.In addition,TFS markedly decreased the expression and phosphorylation of mTOR,indicating that activation of TFS may be associated with the mTORmediated autophagy pathway.This study provides new insights into the mechanism of the immunosuppressive effects of TFS on non-target aquatic hosts and suggests that the existence of TFS in aquatic environments may contribute to outbreaks of viral diseases.
基金Supported by National Science and Technology Projects （2012BAD19B03）.
文摘[ Objective] The paper was to confirm the best application period and frequency of 75% trifloxystrobin ·tebuconazole WG against rice blast and rice sheath blight. [ Method] Influences of different dosages and different application periods of 75% trifloxystrobin · tebuconazole WG on control effects against rice blast and rice sheath blight, as well as their effects on rice yields were studied in the paper. [Result] The control effects of three different fungicides application treatments against rice sheath blight were 80.24%, 83.0% and 67.99%, and the control effects against rice blast were 56.4%, 49.11% and 61.1%, respective- ly. Advanced application of fungicide for two times had good prevention effect against rice sheath blight ; properly delayed application of fungicides for two times was conducive to improving the control effect against rice blast, and one time application of sufficient fungicide during middle booting stage had higher control effect than application for two times. Effective panicle number per unit area, total grain number, 1 000-grain weight and moisture content of various fungicide application treat- ments did not have significant difference with those of the treatments without fungicide application, but grain number per panicle in treatments applied with fungicide was higher than the treatment without application. [ Conclusion] 75% Trifloxystrobin ·tebuconazole WG has better control effect on rice blast and sheath blight, which helps to promote the formation of rice grain and increases yield significantly. The fungicide application against rice sheath blight should be appropriately ad- vanced, and application for one time against panicle blast after middle booting stage is helpful to improve the control effect.
