Electric Shock Induces Long-lasting Innate Immune Response In Drosophila Melanogaster

Electric shock is a source of stimulation that is widely used in biological experiments.In fruit fly related research,electric shock is mainly used as a harmful physical stimulus to train fruit flies,and is used in a variety of behavioral analysis such as avoidance,exercise,stress,learning and memory.However,little is known about the effects of electrical stimulation on the physiological,biochemical,and gene expression of Drosophila.Through in-depth analysis of differential expression profiles of transcriptomes,this paper found that electrical stimulation has a significant impact on a variety of important physiological and biochemical processes in Drosophila including innate immune responses.Further studies on antimicrobial peptides have shown that an innate immune response of up to 10 days can be induced with only one electrical stimulation treatment.Interestingly,the induction of innate immunity by electric shock can even last until the next generation.In this paper,the second generation high-throughput sequencing method was used to obtain the transcriptome sequence of the electric shocked Drosophila,and then through bioinformatics analysis,6944 differentially expressed genes were found,of which 3737 genes were up-regulated and 3207 genes were down-regulated.Among the GO enrichment classification items involved in these differentially expressed genes,the biological processes involved mainly include free radical scavenging,immune system,humoral immune response,peptide biosynthesis,mitotic cell cycle,ribosomal biosynthesis,cellular immune response,non-coding RNA processing,DNA repair,gene epigenetics,histone acetylation,DNA replication etc.;the cellular components involved mainly include chromosome components,nucleoplasm components,nuclear chromosome components,nucleolar components,cytoplasmic components,cytoplasmic vesicle components,cell cortex components,cell division components,cytoskeletal components,organelle components etc.;molecular functions involved include ribosome structural composition,nuclease activity,histone binding,mRNA binding,GTP binding,and the like.Our analysis showed that various physiological processes in the body of the fruit fly were affected by electric shock,and the difference in the expression of innate immune-related genes was particularly significant.Therefore,we designed experiments to further verify and explore the innate immune response induced by electric shock.The induced expression of the antimicrobial peptide gene is an important part of the systemic innate immune response of Drosophila,so changes in the expression level of the antimicrobial peptide gene can be used to detect the innate immune response in Drosophila.We used real-time fluorescent quantitative PCR to detect the relative levels of antibacterial peptide mRNA at different time points after the electric shock,including 2hr,4hr,12 hr or 24 hr,and found that the expression level of antibacterial peptide in the fruit fly was 2 hours after being shocked.There has been a significant increase.Shocked with different voltage intensities including 30 v,60v,90 v,120v or 150 v induces an increase in the antimicrobial peptides gene expression.We then tested the relative expression levels of antimicrobial peptides on 5 days,10 days or 15 days after the shock.The expression level of the antibacterial peptide was found to be higher than that of the non-shock control five days and ten days after the electric shock,but the relative expression level of the antimicrobial peptide was lowered to the level of the control on the fifteenth day after the electric shock.Thus,a single electric shock treatment can induce long-term but not lifetime innate immune response.Interestingly,when I examinated the F1 progenies of shocked males and untreated females,I found that the relative antimicrobial peptides gene expression was significantly higher than untreated controls as well.This suggests that electric shock-induced innate immune responses in Drosophila can be transmitted between generations.This effect might require epigenetic modification,but the involved molecular mechanism is still await of further investigation.