Biological Study On Individual Death Of Drosophila Melanogaster

When a multicellular organism dies,its time as an individual is over,but the cells that make up it will remain active after death for a considerable period.In recent years,many literatures have reported the temporal changes of gene expression after individual death,and even the time of death can be predicted accurately through the changes of gene expression.Compared to after death stage,the gene expression data in the dying stage are harder to come by.One of the reason is that dying stage are hard to define,so there are few reports on the expression of individual genes during the dying stage.Drosophila melanogaster is an excellent model organism.In this paper,based on a large amount of behavioral data,I determine a fly as dying fly if it has been in a supine posture for more than 20 minutes.A real-time monitoring and recording device was set up to allow efficiently collecting the near-death,death and control fly samples.RNA was extracted from fly heads and sent out for lncRNA sequencing.The sequencing results showed that the expression levels of stress response,cell proliferation and differentiation genes in the dying flies were significantly different from those of death flies or control flies.The nervous system plays a leading role in the regulation of physiological functions.Central nervous system diseases rank number one among all causes of residents death,according to China's the third national investigation.As an important model of neurobiology,Drosophila models of many human central nervous system diseases have been constructed.However,how the central nervous system regulates the basic life activities in Drosophila remains unclear.In this study,I use thermogenetic tools to artificially activated the majority of neurons in the adult fly brain(Elav-Gal4>UAS-TrpA1 or ChaT-Gal4>UAS-TrpA1).The results show that shifting flies into restrictive temperature for 6 hours is sufficient to induce irreversible death,suggesting that normal brain function is important for the survival of adult flies.Thus,the central nervous system of Drosophila melanogaster might play an important and evolutionarily conserved role in regulating essential physiological processes.In order to identify brain circuits that control the essential physiology,I screened 576 Gal4 strains that mainly labeled the central nervous system with similar thermogenetic approaches to artificially activate or block neuronal activity and observe the lethality rate.The screening reveals 29 lines that resulted in a mortality rate greater than 80% after 48 hours of neuronal blockade or activation;among them,the mortality rate of 16 lines reaches 100%.In addition,my analyses suggest that 12 h of treatment was a turning point with a sharp increase inmortality.Only 9 of the above 29 lines show a mortality rate higher than 80% after 12 h of temperature shift.