Effects Of Mixed Exposure To Methyl And Propyl Parabens On Genes Related To Stress Resistance, Reproduction And Vitellogenin Expression In Drosophila

P-hydroxybenzoic acid esters,also known as parabens,are a class of esters formed by the dehydration condensation of p-hydroxybenzoic acid and alcohols.Because of its low toxicity,high efficiency,broad-spectrum antibacterial characteristics,it is widely used as a preservative in personal care products,medicines and food.Methylparaben（MP）and propylparaben（PP）are used most frequently.Parabens have always been considered relatively safe preservatives,but studies have shown that they have estrogenic effects,and their effects on the growth,development and reproductive system of organisms cannot be ignored.Therefore,studying the effects of parabens on reproduction and Yolk Protein expression of D.melanogaster is helpful to evaluate the safety of parabens as preservatives.In this study,the Canton-S strain of Drosophila melanogaster was used as experimental material.D.melanogaster was exposed through a mixture of MP and PP（mass ratio 1:1）by control group 0 mg/L and concentration groups of 300 mg/L,700 mg/L,and 1000 mg/L for 5 d,10 d,15 d,20 d and 25 d to explore its effects on the expression of anti-stimulus,reproduction and vitellin-related genes PI3K,AKT1,dTOR,EcR,JHAMT and Yolk1 of D.melanogaster from the physiological and molecular levels.The results are as follows:（1）The climbing ability of male and female fruit flies basically decreased with the extension of days after MP and PP mixed exposure.In the high concentration group 1000 mg/L,the climbing ability of female flies was extremely significantly reduced at 5 d and 10 d（P<0.01）,while the climbing ability of male fruit flies was significantly reduced when exposed for 5 days（P<0.05）,and the climbing ability was extremely significantly reduced at 25 days（P<0.01）.However,the climbing ability decline in the low and medium concentration groups was not significant In terms of hunger resistance ability,female flies exposed for 10 d,the low-concentration group increased extremely significantly（P<0.01）,the high-concentration group increased significantly（P<0.05）,and the medium and high-concentration groups began to be extremely significant decrease after exposure for 15 d（P<0.01）,the hunger resistance ability of male fruit flies is greatly reduced compared with females,and it basically shows a downward trend with the prolongation of exposure days.The hunger resistance ability of the concentration group increased significantly（P<0.01）after exposure for 5 d.After exposure for 15 d and 20 d,the low and medium concentration groups increased to varying degrees,while the high concentration group exposed for 10 d significantly decreased（P<0.05）.The heat resistance ability of male and female flies decreases with the prolongation of exposure days.Except for female fruit flies,the high concentration began to increase from 15 days,the heat resistance ability of each concentration group decreased,while the heat resistance ability of male fruit flies was significantly reduced（P<0.05）.（2）MP and PP mixed exposure to different days of female fruit flies,concentration group as a whole promote fruit flies spawning,and increased total egg production for 10 consecutive days,and the 700 mg/L group had the most obvious increase.The sexual ability of female fruit flies decreased with the increase of concentration,and the sexual ability of the 300 mg/L group decreased with the extension of exposure days.（3）The relative expression levels of PI3K,AKT1 and dTOR genes in female flies after different days of mixed MP and PP exposure increased to varying degrees,especially exposure 15 d,the expression levels of the three genes increased in the 300 mg/L and 700 mg/L group.The relative expression of EcR gene changed in the same trend in the 10 d.and the relative expression in the concentration group was down-regulated,and the relative expression in the 700 mg/L group was the highest.The relative expression in the concentration group was increased sharply after exposure for 15 d,and the relative expression in the 700 mg/L group was the highest.The JHAMT gene expression increased to varying degrees,since 15 d of exposure,however,JHAMT expression has been almost upregulated in the concentration groups,at 25 d,relative expression levels of the three concentration groups all increased,And the relative expression level of the 300 mg/L group is the highest,which is significantly different from other groups.The concentration groups up-regulated the expression of Yolk1 gene.In summary,this study investigated the effects of MP and PP mixed exposure on anti-stimulus,reproduction,and signal pathways and genes that regulate the expression of vitellin in female fruit flies,preliminarily explored the effects of the mixture of MP and PP on the reproduction of Drosophila,and providing data reference for evaluating the safety of parabens.