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Coccomyxa actinabiotis sp. nov. (Trebouxiophyceae, Chlorophyta), a new green microalga living in the spent fuel cooling pool of a nuclear reactor
Author(s) -
Rivasseau Corinne,
Farhi Emmanuel,
Compag Estelle,
Gouvion Saint Cyr Diane,
Lis Robert,
Falconet Denis,
Kuntz Marcel,
Atteia Ariane,
Couté Alain
Publication year - 2016
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/jpy.12442
Subject(s) - biology , extremophile , deinococcus radiodurans , ribosomal rna , deinococcus , botany , bacteria , microorganism , gene , genetics
Life can thrive in extreme environments where inhospitable conditions prevail. Organisms which resist, for example, acidity, pressure, low or high temperature, have been found in harsh environments. Most of them are bacteria and archaea. The bacterium Deinococcus radiodurans is considered to be a champion among all living organisms, surviving extreme ionizing radiation levels. We have discovered a new extremophile eukaryotic organism that possesses a resistance to ionizing radiations similar to that of D. radiodurans . This microorganism, an autotrophic freshwater green microalga, lives in a peculiar environment, namely the cooling pool of a nuclear reactor containing spent nuclear fuels, where it is continuously submitted to nutritive, metallic, and radiative stress. We investigated its morphology and its ultrastructure by light, fluorescence and electron microscopy as well as its biochemical properties. Its resistance to UV and gamma radiation was assessed. When submitted to different dose rates of the order of some tens of mGy · h −1 to several thousands of Gy · h −1 , the microalga revealed to be able to survive intense gamma‐rays irradiation, up to 2,000 times the dose lethal to human. The nuclear genome region spanning the genes for small subunit ribosomal RNA ‐Internal Transcribed Spacer ( ITS ) 1‐5.8S rRNA ‐ ITS 2‐28S rRNA (beginning) was sequenced (4,065 bp). The phylogenetic position of the microalga was inferred from the 18S rRNA gene. All the revealed characteristics make the alga a new species of the genus Coccomyxa in the class Trebouxiophyceae , which we name Coccomyxa actinabiotis sp. nov.