Distribution of ice activities among polar microalgae

Abstract

Diatoms and other microalgae in the sea are mainly primary producers in polar marine ecosystem. Of these organisms, polar cryophilic microalgae are cold-adapted microorganisms which grow well at 2℃ to 3℃ but not more than 10℃. Culture collections in Korea Polar Research Institute (KOPRI) have more than 100 microalgal strains which are obtained from Dasan Station, Arctic and King Sejong Station, Antarctic. These organisms are cultivating at 2℃ and are exposed to light for 24 hours. It is known that microorganisms living in polar regions have several strategies for surviving from extremely cold environment such as excretion of ice-binding proteins .We screened the activity of ice-binding proteins in order to check the existence of ice-binding proteins excreted from microalgae in culture collection. So far, we measured the ice binding activity of AnM and ArM series by ice-pitting instrument. Among them, it was found that KOPRI AnM0013, KOPRI AnM0020, KOPRI AnM0021, KOPRI AnM0035, KOPRI AnM0040, KOPRI AnM0060 and KOPRI ArM0051 have relatively strong ice binding activity. Two of them, KOPRI AnM0020 and KOPRI AnM0060 have the strongest activity by morphological observation of ice pittings. Also, we conducted SDS-PAGE in order to confirm the distributions of proteins excreted from cells. In the future, we are going to measure the ice binding activity of the freshwater microalgae in the polar area and to screen the activity of antifreeze proteins in polar microalgae.