The Research On Dopamine Regulating Lifespan And Behaviors In Silkworm, Bombyx Mori

Melanin is a coloring pattern which is very important for generating insect body color diversity in nature.Meanwhile,melanin has many biological advantages such as the diversity of body color,important regulators in ecological adaptation and so on.It is closely related to body resistance,quality of life,energy conservation,courtship ability,fertility and innate immunity.The silkworm,Bombyx mori,is a kind of Lepidoptera,with a long history of domestication and abundant genetic mutations.At present,there are more than seven hundred strains of genetic mutations in silkworms.The silkworm is a valuable research material which is involved in body color and mimicry,life and aging,medicine and pathology,ecology and environment,and domestication etc.Recently,our research team has found a longevity and phenotype of a recessive melanic mutant strain?sex-controlled melanism,sml?.Its black male moths have significant longevity characteristics.However,what causes the phenomenon of longevity of the melanized individuals are still not clearly.My research is based on the longevity and melanin phenotype of the melanic sml mutant.By choosing many silkworm related mutants which are melanin metabolic pathway materials,we had investigated the difference in longevity of those mutant strains.Our study found that dopamine is not only involved in the melanin metabolism pathway,but also serves as one of the material bases for regulating the lifespan and affecting age-related behaviors in silkworms.The study lays a good foundation for further exploration of the molecular mechanism of dopamine in physiological function and control of the lifespan.Therefore,using silkworm as an experimental animal model to explore and study the dopamine participation in the control mechanism of lifespan is very significant.At the same time,the prospects are very broad in the future.The related research results are as follows:1.Lifespan is closely related to dopamine in silkworm.In order to explore the link between the melanin and lifespan,we had investigated the difference in several melanic longevity mutant strains in silkworms.We have found that the lifespan of black moth?Dz-mln,Dz-Bm?are significantly higher than the control Dz.Therefore,we speculate that melanization may extend the lifespan in silkworms.In addition,we also found the white moth Dz-ch is significantly higher than the control Dz.While the lifespan of another sch,whose female moth is significantly shorter than the control Dz.According to those moths'genetic background,we found that they were all involve in the melanin metabolic pathways in silkworms.The dopamine content may different in those moths'body.Based on our large amount of statistical data,we speculate that some of the melanic strains accompanying with the longevity may be closely related with the appropriate dopamine levels in vivo.For the sake of confirming our hypothesis,we used the UPLC-MC/MC method to detect the levels of dopamine in the melanic mutant strains and control strains.The related experimental results confirmed that the melanic mutant strains who have a melanism and longevity phenotype,are accompanying the higher levels of dopamine.It is further confirmed that dopamine may involve in the mechanism of lifespan in silkworms.The results confirmed that dopamine could participate in the regulation of lifespan process in silkworm.2.Dopamine regulate lifespan and behaviors in silkworm,Bombyx moriTo more clearly explore the mechanism of dopamine participation in regulation of lifespan.Next,the different dose levels of dopamine and its inhibitors were injected into the wild-type strains.It was found that the injection of dopamine at a range of suitable doses could prolong the lifespan of silkworm moths.As a result,it was found that dopamine could extend the lifespan of silkworm moth at a certain dose range(2.5x10^-3mmol¹.25x10^-3 mmol).However,the higher doses of dopamine(5x10^-3 mmol)could lead to the lifespan was shortened in the silkworm moth;Moreover,the lower dose of dopamine(5x10^-5 mmol)was not significant for the lifespan in the silkworm moth.In contrast,the inhibitors could cause a reduction for the lifespan in the silkworm moths.Our research confirmed that the suitable dosing ranges of dopamine can prolong the life quality and cause the longevity in silkworm moth.For the sake of exploring what the pathway of dopamine could cause the longevity it is in silkworm moths,we examined the total antioxidant capacity of the treated silkworm moths and some related strains.After the dopamine injection,it was found that the total antioxidant capacity was increased in those silkworm moths;The total antioxidant capacity of the longevity mutant silkworm moth?the higher dopamine content?was also higher than the wild type Dz.The research results confirmed that the increase of dopamine could cause the longevity in silkworm moth,which may play a role through raising the total body resistance in vivo.In order to explore the effect of dopamine on the behavior in silkworms,we have investigated the behavioral changes of the silkworm moths.We found that dopamine could increases the males'courtship ability and improve the courtship ability of the elderly moths.In addition,after the dopamine injection in vivo,the proportion of homosexual mating in male moth increases.Our results proved that dopamine has a very important and significant effect on the behaviors in silkworm.