Eva Philipp

Elucidating the mechanisms underlying longevity is a pivotal challenge in biomedical sciences. The bivalve Arctica islandica is a unique model for ageing research as it is one of the longest-lived complex animal species on earth with a maximum life span of > 400 years. A repeatedly presumed strategy leading to the extreme longevity in A. islandica is the occurrence of self-induced phases of metabolic rate depression (MRD). Duration and frequency of MRD phases may vary between populations due to different environmental conditions like temperature or oxygen and thus might be one factor determining the difference in maximum life span observed between A. islandica populations. While a maximum age of 410 years is found for the Iceland population, A. islandica from the Baltic Sea population show a shorter life span of < 50 years. To investigate the role of MRD phases to attain a long life span and for a comprehensive overview of transcriptional changes under different oxygen/metabolic conditions, transcriptomes of normoxic, anoxic and reoxygenation treated individuals of A. islandica from the long lived Iceland population will be generated by pyrosequencing (Illumina). Gene expression changes will be analyzed with the help of a previously generated A. islandica transcriptome (2.9 mio reads, 454 technology). Gene expression analysis (qPCR) of selected candidate genes from the transcriptome approach will then be used to investigate population specific MRD responses under different oxygen (normoxia, anoxia, reoxygenation) and temperature (4, 7, 14 °C) regimes. Old individuals of both populations will be used for this approach and individual ages will be determined by age rings counts in the shell. Transcriptional responses will be compared with environmental temperature and oxygen conditions of the two populations, deduced from measurements of respective shell proxies (IFM-Geomar) and data-mining of literature and public databases. The results will provide insight whether MRD phases may be beneficial to attain a long life span and elucidate the role of environmental factors on modulating MRD patterns and maximum life span in A. islandica.