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Proceedings of the 31 st European Peptide SymposiumMichal Lebl, Morten Meldal, Knud J. Jensen, Thomas Hoeg-Jensen (Editors)European Peptide Society, 2010Protection Against Heat Stress Injury of Deuterohemin Peptidein C. elegansGuan Wang, Pengfei Li, Shuwen Guan, Changrun Guo, Limin ZhuHongkuan Fan, and Liping Wang *College of Life Science, Jilin University, Changchun, 130012, P.R. ChinaIntroductionHeat stress will have a profound impact on Caenorhabditis elegans(C.elegans. Mild heatstimulation can cause hormesis and lead to extend the longevity. On the other handcontinued heat stress would cause reduced life expectancy [1]. In this experiment C.eleganswas kept at 30 o C and 35 o C after adult to establish the sustained heat stress model. Adeuterohemin peptide called DhHP-6, which have already been proved that it can extendthe lifespan of C.elegans [2], can raise the survival rate of C.elegans cultured in theenvironment of 30 o C and extend the longevity in the 35 o C. There have been the similarresults in the daf-16 or sir-2.1 mutation strain indicating that DhHP-6 can protect C.elegansform the heat stress in a sir-2.1 and daf-16 independent way. The subsequent experimentused real time-PCR to investigate the differences in gene expression before and after heatshock. The results show that DhHP-6 can significantly increase the expression of heatshock protein HSP-16.1 and decrease the expression of sir-2.1,msh-2 and xpa-1 after heatshock. Combining with other gene data suggest a possible explanation for the protectiveeffect of DhHP-6 on the C.elegans: the presence of DhHP-6 can decrease the highoxidation level caused by heat shock and accelerate the main response to stress byshortening the time for HSP's up-regulation.Results and DiscussionDhHP-6, as a kind of peroxidase simulation, can help C.elegans to prolong the lifespan andincrease the survival rate under a model of heat environment established in this experiment.Experiment proved that whether at 30 o C or 35 o C DhHP-6 have a protective effect on thewild type of C.elegans under the heat stress. DhHP-6 still have obvious protect effect totwo kinds of mutations worm,CF1038(daf-16 [3] mutations)and VC199 (sir-2.1 [4]mutations), which of the mutation gene are the key factor in the two most important ofsignaling pathways of stress resistance in the two heat stress conditions. The mutation ofdaf-16 and sir-2.1 does not effect the protection of DhHP-6 to worm under heat stressimplying DhHP-6 heat protective effect has no daf-16 and sir-2.1 dependency. Anothernotable result is comparison with wild type loss of daf-16 or sir-2.1 seen to lead to decreasethe tolerance of heat for C.elegans.To further explore which pathway the DhHP-6 of the heat protective effect forC.elegans may be adopted. This study examines the effect of DhHP-6 to gene expressionfor C.elegans under heat stress. The results can show that the gene expression of the ctl-1one of cytoplasmic catalase in C.elegans [5] displays a certain reduction after given DhHP-6 in the wild type suggesting that the DhHP-6 can reduce oxidative pressure of C.elegans.The result after heat shock shows that the heat stress protective effect of DhHP-6 inC.elegans is likely to be achieved by effect on the level of intracellular oxidation. As forgene sir-2.1, both in wild-type and the daf-16 mutant strain have shown a reduction of theexpression after given DhHP-6. The result may be due to DhHP-6 that can reduce the levelof oxidative stress in C.elegans. The down regulation of sir-2.1 after heat shock alsoreflects the heat stress resistance of DhHP-6 to the early life of C.elegans is not dependenton sir-2.1 gene pathway, which is consistent with the results that DhHP-6 heat protectiveeffect have not sir-2.1 dependency. After that we examined hsp-16.1, an important HSP inC.elegans [6]. The results show that the expression of hsp-16.1 was significantly increasedin the presence of DhHP-6 with further increase after heat shock. But the expression of hsp-16.1 wasn't increased in the absence of DhHP-6 after heat shock that may be due to theshort time interval between heat shock and extraction of total RNA so that there's notenough time to change the expression and the existence of DhHP-6 can shorten the time forstress resistance. These results also indicated that the DhHP-6 protects C. elegans reducingheat damage from heat environment by up-regulation hsp-16.1. It is notable that there aresimilar results in the daf-16 mutant strain indicating that the up-regulation effect to hsp-348