| The ecdysteroid receptor(ECR)plays an important roles in controlling insect ecdysisthe and normal development growth.ECR can bind to ultraspiracle(USP)becoming EcR/USP heterodimer which stimulates the process of insect molting cascade,and effect insect development,metamorphosis and reproduction.Tailless is a transcription factor,belonging to the steroid nuclear receptor family.The physiological ligand of this receptor is still unidentified and belong to orphan nuclear receptor.Tailless has been found to regulate the segmentation and the production of the nervous system.The Extradeticle gene was a cofactor,it was requisite in the development of arthropod appendages and the formation of insect back sheets.Homothorax is also a cofactor,which plays an important role in the formation of appendages and nervous system.Aspartame and Sodium benzoate,are widely used in modern food.Although the harmfulness has been reduced to the lowest level,the risk of these substances causing harm to the human body still exists.Studies have shown that aspartame has an effect on the growth and development of mice,flaming red ants,human brain and Drosophila nervous system,and sodium benzoate has reproductive and neurotoxicity to beautiful nematodes,growth and development of crawler and thermophilic four-membrane insects,and has an effect on the nervous system of rats.Polyrhachis vicina Roger is a typical social insect,it has obvious characteristics of caste differentiation,This species also has a certain nutritional value,it can be used to cure some human diseases,and get easily.Therefore,it is also a good material for experiment.This study focuses on two part.Part one,RNAi technique was used to silence PvEcR and PvTll.Observation of morphological changes of the ant bodies before and after interference were statistics,which was used to evaluate PvEcR and PvTll regulating the growth and development of P.vinica.qRT-PCR technique was used to explore the correlation between PvEcR with PvTll and PvExd at mRNA level,Analysis of the effects of three factors on the growth and development of P.vicina.And its influence on different classes of insects.Part two,two kinds of food additives,Aspartame and sodium benzoate,were used to treat different caste adults of P.vicina with different concentrations,qRT-PCR technique was used to detect the expression of PvEcR?PvTll?PvExd and PvHth in the body before and after the feeding treatment at the level of mRNA.Observation and statistics of phenotypic changes of the ants before and after feeding treatment were performence.The effects of aspartame and sodium benzoate on the growth,development and grade differentiation were speculated.The results are as follows:1.The dsEcR was introduced into the ant body by feeding.The results showed that the 4th instar larvae were abnormal development,the molting of pupaes were blocked,the abdomen of workers were abnormal and the wings of males were incomplete.The abdomen of the females turned brown;the body weight of the ants decreased;except for the female,the mortality rate of the males and the workers increased,which indicated that PvEcR-RNAi had a direct effect on the normal growth and development of P.vicina.QRT-PCR technique was used to study the correlation between PvEcR and PvTll,as well as PvExd in mRNA.We can see that after PvEcR-RNAi,The levels of PvEcR mRNA were significantly down-regulated in pupa,workers,males and females.The effect on PvTll of males was the greatest,females was second,workers and the 4th instar larvae was weaker.The effect on PvExd in the 4th instar larvae was the greatest,females were the second,pupa and workers were the smallest,and the change of PvExd in males was obvious.The contrast of different genes in the same caste showed that the influence of PvTll expression on different caste adults was greater than that of PvExd after PvEcR interference,which may exhibit that the correlation between PvEcR and PvTll was greater than that of PvEcR and PvExd.2.Feeding method were used to knock down PvTll.The results showed that the expression level of PvTll mRNA in 4th instar larvae,pupae,workers,males and females decreased significantly after PvTll-RNAi.PvEcR and PvExd were up-regulated significantly in male ants after PvTll-RNAi,but down-regulated significantly in 4th instar larvae,pupae,workers and females,but there was no significant change in PvEcR in workers.The above studies showed not obvious changes for PvExd after PvTll-RNAi in worker ants.The results show that there is a certain correlation between PvTll and PvEcR as well as PvExd.The shape changes of the ants were observed.It was found that the mortality changes of the ants had the lowest effect on female ants,followed by male ants and the third pupae,and had the greatest effect on the 4th instar larvae.The phenotypes of 4th instar larvae,pupa and adult adults of different castes before and after PvTll-RNAi were observed by ZEISS anatomical microscope.The results showed that the effect of PvTll-RNAi to larvae were greater than that of adults in shapes.3.Five concentrations of aspartame were used to feed ants to detect the expression of PvEcR?PvTll?PvExd?PvHth.The results showed that after feeding with Aspartame,PvEcR only changed significantly in female ants(P<0.05),PvTll in the 4th instar larvae and pupae(P<0.01),and the trend was the same as that in the 4th instar larvae and pupae(P<0.01).On the 12th day after soaking the 4th instar larvae,PvExd was significantly changed(P<0.01),suggesting the effect of Aspartame on gene expression.The statistical mortality showed that this substance had the lowest effect on females,followed by males,and had the greatest effect on pupae.The results of body weight measurement showed that the weight of female and male ants decreased and there were cross-changes between 4th instar and pupae.The effect of this substance on body length was not obvious,and the phenotypic abnormality was not obvious.It was suggested that Aspartame had a great effect on the life span of P.vicina.4.Five concentrations of sodium benzoate were used to feed ants to detect the expression of PvEcR?PvTll?PvExd?PvHth.After statistical analysis,1.5g/L was selected for follow-up experiments.The results showed that after sodium benzoate was treated with different caste adults of P.vicina,the PvEcR was significantly down-regulated in females and pupae(P<0.01).PvTll was significantly down-regulated in females and up-regulated in pupae(P<0.05),PvExd in males and female ants(P<0.05).It is suggested that sodium benzoate had a certain effect on the normal gene expression,and the effect of sodium benzoate was more obvious than aspartame.The statistical mortality showed that sodium benzoate had the greatest effect on pupae,followed by 4th instar larvae,and female ants had the lowest effect.The results of body weight measurement showed that the body weight of the adults was decreased and the shape of the worm was slightly abnormal.It is suggested that sodium benzoate has a certain effect on the growth and development of ants and the expression of their genes.In this study,the correlation between PvEcR and PvTll as well as PvExd was investigated for the first time.PvTll was silenced effectively by RNAi technique for the first time.The importance of this gene to the growth and development of P.vicina was observed.and the correlation between PvTll and PvEcR as well as PvExd was explored from the level of mRNA.It can provide a basis for further study of the three genes in the future.In this study,the effects of different concentrations of aspartame and sodium benzoate on the normal expression of PvTll?PvExd?PvHth in P.vicina,were detected for the first time.It provides some research basis for understanding the toxicological effect of these two kinds of food additives. |
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