| Because of the abuse of pesticide, there is more and more pesticide residues in the environment. People’s long-term exposure to environmental pesticide can cause various diseases such as cancer. How to effectively detect the trace pesticide residues in the environment is an issue of great concern to scientists now. Due to the long-term artificial environmental breeding, silkworm resistance quality has greatly degraded, which is more sensitive to various pollutants. Through distribution in a certain area of monitoring, abnormal biomarkers, thereby warning of pesticide residues in the environment pollution occurs. This study used the sensitivity of the silkworm to explore whether it can be used as a biomarker of carrier to monitor pesticide residues in the environment. In our experiment, we used male and female silkworm in fifth instar. Under this concentration, we fed mulberry leaves exposed totrace phoxim to male and female silkworms continuously until they mounted. We investigated and counted growth and development as well as its main economic indicators of the silkworm under treatment of trace concentrations phoxim, And then the enzymatic activity of CarE, ACP and AKP were measured. At the same time we also used serum containing of0.05mg/L of phoxim to culture BmN cells and detected cell damage through microscopic observation and single cell gel electrophoresis technology. Through these studies we mainly got the following results:1. Continuous trace concentrations (0.05mg/L) continuous feeding of phoxim has little impact on male and female silkworm individual weight. Compared with the control group, the female silkworm P=0.547>0.05, male silkworm P=0.633>0.05, showing no significant differences exist among them. We investigated and counted the nest, cocoon and other economic indicators of female and male silkworm among the treatment group and the control group, compared with the control group P<0.01in terms of mounting and cocoon, which indicate there was significant difference affected by the phoxim. However the other major economic indicators by t test, there is no significant difference from the control group with P>0.05. Trace concentrations of phoxim affected the mounting, cocoon silkworm, which indicated that it influenced normal physiological function of silkworm and could be used in subsequent experiment.2. Under the stress of0.05mg/L organophosphorus pesticides phoxim, we measured CarE, ACP and AKP enzyme activity of the male and female silkworm in the gut, fat body and the blood, which varied differently in these tissues. The CarE enzyme activity of male and female silkworm were supressed in the three organizations.The female silkworms were significantly supressed after the Id and3d, while male silkworms were significantly supressed from1d to7d; The ACP enzymen activity in three organizations were also supressed, especifally the inhibitory effect of the late5th instar midgut was notable, and female silkworm fat body ACP activity hibition was highly significant. After trace phoxin treatment, AKP activity in the three organizations increased, the fat body and blood of enzyme activity have very significant and significant differences compared with controls. After comprehensive comparison, the CarE can be used as candidate biomarkers to detect trace organophosphorus pesticide residues in the environment.3. After the0.05mg/L organophosphorus pesticides phoxim treatment, major elements K and Mg content in the blood of silkworm are higher than that in the control group, Na and Ca content lower than that in the control groups, the K content increased most significantly, were21.2%(female) and18.3%(males). Trace elements Fe, Cu content increased, Mn, Zn content decreased, which Cu, Mn, Zn there was a significant difference in the change, Cu increased15%(females) and19%(male), Mn reduced by23.0%(female) and32.4%(male), Zn reduced by24%(females) and41%(male). Comprehensive analysis life elements of silkworm blood, K, Cu, Mn, and Zn can be used as organophosphorus pesticide residue monitoring of candidate biomarkers, but its physiological function requires further study.4. Microscopic observation of cultured cells showed that apoptosis occurred in most of the cells cultured by serum containing0.05mg/L phoxim after24h. The CAPS software showed BmN cells of treatment group exhibited as high as95.34%tail phenomenon, in control group1and2of BmN cells only6.28%and6.28%tail phenomenon appeared respectively, suggesting trace phoxim will cause serious damage to the cell DNA. Using silkworm BmN cells sensitivity to pesticides can also be used as acandidate biomarker to monitor trace pesticide residues in the environment.5. In this experiment, we adopted the0.05mg/L of phoxim concentration, which is the national standard for pesticide recidues on phoxim residue maximum allowable conxentrztion.Under the stress of this concentration, CarE, ACP and AKP enzyme activity in5th silkworn intestine, fat body and blood, life element content and activity of in vivo cultured cells have obvious response compared with control groups. This showed that the silkworm is very sensitive to organophosphorus pesticide.Even by trace concentration of stress, the physiological aspect will change significantly, these changes pare can be used as a candidate biomarker of environmental detection of pesticide residue. |
PDF Full Text Request