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Epiphytic bacteria on the Antarctic ice diatom Amphiprora kufferathii M anguin cleave hydrogen peroxide produced during algal photosynthesis
Author(s) -
Hünken M.,
Harder J.,
Kirst G. O.
Publication year - 2008
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.2008.00040.x
Subject(s) - biology , axenic , bacteria , diatom , microbiology and biotechnology , catalase , proteobacteria , botany , marine bacteriophage , biochemistry , enzyme , 16s ribosomal rna , genetics
The Antarctic ice diatom Amphiprora kufferathii M anguin is always accompanied by epiphytic bacteria in its natural habitat. To investigate the nature of this relationship, axenic cultures of A. kufferathii were obtained by ampicillin treatment. Diatom cultures without bacteria were less dense. The bacteria were shown to consume hydrogen peroxide produced by the diatom during photosysnthesis and algal photosynthesis after a hydrogen peroxide shock recovered faster in the presence of bacteria. Three proteobacterial strains isolated from a culture of A . kufferathii were phylogenetically affiliated with the alphaproteobacterial genus Sulfitobacter , the gammaproteobacterial genus Colwellia , and the genus Pibocella of the Bacteriodetes . Native protein gel electrophoresis and enzyme activity staining revealed the presence of superoxide dismutase and glutathione reductase in the isolated bacteria and in A. kufferathii cultures. Catalase was detected in bacterial extracts but not in axenic cultures of A. kufferathii . These observations indicate that the epiphytic bacteria make a significant contribution to the diatom’s antioxidative defences. The relationship between the bacteria and A. kufferathii seems to be beneficial for both partners and enhances growth of Amphiprora in the sea ice.