Studies On Nutritional Analysis Of Lipids And Their Mechanism Of Immune Regulation In Chrysomya Megacephala (Fabricius)

Chrysomya megacephala（Fabricius）（Diptera:Calliphoridae） belongs to Chrysomya genus,Calliphoridae family,Diptera order,The common vehicle insect.C.megacephala is used for material,This article analysed the component of C.megacephala,especially nutrition of lipid,evaluated extraction method and nutrition function of lipid;Otherwise, Immunology method was used to research lipid in cell immunology mechanism afrter intrusing by sexterior microbe,the main findings are as follows:1.Analyses of Nutritional Components in C.megacephala（Fabricius）The analyses of nutritional Components of C.megacephala（Fabricius） were determined in this research.The results showed that the nutritioned dry content of C. megacephala larva,pupa and adult were 6.83%,2.07%,3.70%,crude protein were 63.72%,76.81%and 70.54%,and crude fat were 16.43%,12.82%,7.23%,respectively. The total amino acid were 56.39%,55.61%and 59.12%,essential amino acid（E） account s for 48.34%,53.08%and 43.91%of total amino acid,E/N were 10.94,1.13 and 0.81,E/T were 3.22,3.54 and 2.93,respectively.The unsaturated fatty acidsfor uas 68.1%,61.9%,65.9%of the total fatty acids.The nutritional components of C. megacephala larva,pupa and adult contained microelement and frequent element that was necessitous to human being or animal,but not inspected the toxic heavy metals, such as Cd or Pb.The index of C.megacephala nutritional components were higher than fish meal,housefly and Larv ussore pupa so that it was a better resource of insect protein.2.Reducing blood lipids effect and Phospho-lipin extraction and determination of oil from C.megacephala Fabricius larvaeEffect of larval oil of C.megacephala Fabricius on hyperlipemia was studied. Hyperlipemia model was established in mice.The oil was garaged to the mice for 5 weeks.Blood samples were sampled.The levels of blood lipids were detected.The pathological changes in the liver were observed microscopically.The result reveals that larva oil of C.megacephala Fabricius could obviously reduce contents of TC,TG,and LDL-C（p＜0.05 or 0.01）;and the increase of LDL-C（p＜0.05） in serum shows a relationship between the quantity and the effect.Successfully feeding the mice with larva oil of C.megacephala has a protection effect to the liver cells.It can be concluded that larval oil of C.megacephala has a therapeutic effect on hyperlipemia.larvae of C. megacephala phospho-lipin content is 2%-4%,Obtains big end of Jin Yingyou the phosphatide main group to divide into PE and PC,Also PE content＞PC content.3.Eicosanoid regulate the nodulation infect action of Escherichia coli to larvae of C. megacephala.Nodulation is the predominant cellular defense reaction to bacterial challenges in insects.In this study,third instar larvae of C.megacephala were injected with bacteria,E. coli（10⁶ CFU/mL,2 uL）,immediately prior to injection of inhibitors of eicosanoid biosynthesis,which sharply reduced nodulation response.Test larvae were treated with specific inhibitors of phospholipase A₂（dexamethasone）,cyclooxygenase（indomethacin, ibuprofen and piroxicam）,dual cyclooxygenase / lipoxygenase（phenidone） and lipoxygenase（esculetin） that reduced nodulation except esculetin.The influence of bacteria was obvious within 2 h of injection（5 nodules/larva）,and increased to a maximum after 8 h（with 15 nodules/larva）,and then significantly reduced over 24 h（9 nodules/larva）.The inhibitory influence of dexamethasone was apparent within 2 h of injection（4 vs 5 nodules/larva）,and nodulation was significantly reduced,compared to control,over 24 h（5 vs 8 nodules/larva）.Increased dosages of ibuprofen,indomethacin, piroxicam and phenidone led to decreased number of nodules.Nodules continued to exist during the pupal stage.However,the effects of dexamethasone were reversed by treating bacteria-injected insects with an eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid.These findings approved our view that eicosanoid can mediate cellular defense mechanisms in response to bacterial infections in another Dipteran insect C. megacephala.4.Eicosanoid regulate the nodulation infect action of Ureaplasma urealyticum to larvae of C.megacephala.Nodulation is the temporally and quantitatively most important cellular defense response to bacterial,fungal and some viral infections in insects.We tested the hypothesis that prostaglandins and other eicosanoids are responsible for mediating nodulation reactions to bacterial infection in larvae of the blowfly C.megacephala.Third-instar larvae treated with U.urealyticum formed nodules in a challenge dose-dependent manner. Nodulation was evoked shortly after injection and reached a maximum of approximately 25 nodules/larva within 8 h.Larvae treated with the glucocorticoid,dexamethasone and the cyclooxygenase inhibitors,indomethacin and piroxicam were impaired in their ability to form nodules following U.urealyticum infection.The number of nodules decreased with increasing doses of piroxicam.Contrarily,treating larvae with the lipooxygenase inhibitor,esculetin,and the dual cyclooxygenase/lipooxygenase inhibitor,phenidone did not influence nodulation reactions to infection.Supplying dexamethasone-treated larvae with the eicosanoid precursor,arachidonic acid,reversed the inhibitory effect of dexamethasone on nodulation.We infer from these results that eicosanoids mediate nodulation reactions to infection of a bacterial species that lacks cell walls in larvae of the blowfly,C.rnegacephala.5.Eicosanoid regulate the nodulation infect action of AcMNPV to larvae of C. megacephala.The third instar larvae of C.rnegacephala were infected by AcMNPV,the nodulation action was soon engendered,the peak of nodule number presented from 4 h to 10 h and reached maximum at 8 h;the nodule number was 30 per maggot when the AcMNPV concentration of 10⁶ CFU/ml;the nodule number not change along with vary in low concentration range.The nodulation action would significantly decreased if the larvae was infected by phospholipase A₂ inhibitor,dexamethasone,cyclo-oxygenase inhibitor, ibuprofen,indomethacin,piroxicam after injection of AcMNPV;However,the lipoxygenase inhibitors,esculetin,cyclo-oxygenase and lipoxygenase double inhibitors, phenidone has no significant effect on decreasing the number of nodulation action or the ability of forming nodulation.Within certain concentration range,the number of nodulation decreased when the concentration of indomethacin was increased.The effect of nodulation that caused by invasion of AcMNPV can be inhibited by phospholipase A2 inhibitor dexamethasone,while the inhibition can be reversed if the larvae was treated with eicosanoid,which suggests that eicosanoid may involve in the forming ofnodulation.The nodule number was reduced along with the increasement of indomethacin concentration, 24 per maggot treated by dimethyl sulfoxide and 8 per maggot treated by high concentration indomethacin.All the results showed that,eicosanoid can regulate the cellular defense reaction of calliphoridae insect of diptera after they invaded by virus. Eicosanoid hypothesis was further proved in the cellular immune regulation,it exists in cellular immune regulation of C.megacephala.6.Eicosanoid regulate the nodulation infect action of Beauveria bassiana to larvae of C. megacephala.The third instar larvae of C.megacephala were infected by fungus B.bassiana to induce nodulation,the peak of nodule number presented from 6 h to 10 h and reached maximum of 58 at 8 h;the nodule number related to the concentration,40 per maggot of 10⁶ CFU/ml and 5 per maggot in B.bassiana nutrient solution.Treating larvae of C. megaeephala with the Phospholipase A₂ inhibitor,dexamethasone,cyclooxygenase inhibitors,indomethacin,ibuprofen,piroxicam,nodulation reactions to fungal infection were all reduced strongly;but the lipoxygenase inhibitor,esculetin and the dual cyclooxygenase/lipoxygenase inhibitor,phenidone,did not.57 per maggot treated by dimethyl sulfoxide decreased linearly to 10 per maggot treated by high concentration bounaud（P＜0.05）,and no significant difference among high concentration bounaud.The dexamethasone effects on larvae were reversed by treating fungi-injected insects with the eicosanoid-precursor polyunsaturated fatty acid,arachidonic acid.By contrast,palmitic acid,which is not a substate for eicosanoid biosynthesis,did not reverse the influence of dexamethasone on nodulation reactions.7.Inoculate microbes evokes microaggregation reactions in hemocytes isolated from larvae of C.megacephalaHemocytes microaggregation formation is the important process of nodulation,this study indicated that it can be induced by some outcomers,which includes U.urealyticum andEscherichia coli and B.bassiana and AcMNPV be observed under microscoope.The results showed that the apex number of microaggregation appeared after 30 min infection by outcomer microoganisms and also increased with the concentration of microoganisms. To compare with the control group,the ability of formation of microaggregation is decreased in treatment with Phospholipase A₂ inhibitor,dexamethasone,however,the larvae of C.megacephala with injection eicosanoid-precursor polyunsaturated fatty acid, arachidonic acid can reverse the effects of Phospholipase A₂ inhibitor,dexamethasone. The results also showed that cyclooxygenase inhibitors can inhibit the microaggregation formation in effect,and with the negative relative between increased concentration of inhibitors and decresed microoganism number,but the lipoxygenase inhibitor can not affect the microaggregation formed.Thus all the evidence supported the arachidonic acid involved nodulation response reaction.