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Halomethane production by vanadium‐dependent bromoperoxidase in marine Synechococcus
Author(s) -
Johnson Todd L.,
Brahamsha Bianca,
Palenik Brian,
Mühle Jens
Publication year - 2015
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10135
Subject(s) - strain (injury) , chemistry , bromoform , synechococcus , vanadium , cyanobacteria , environmental chemistry , biology , bacteria , chromatography , organic chemistry , genetics , anatomy , chloroform
To investigate the role of vanadium‐dependent bromoperoxidase (VBPO) for the production of halogenated methanes in marine prokaryotes, we measured VBPO activity and halomethane production in two strains of Synechococcus ; one with VBPO (strain CC9311) and one without VBPO (strain WH8102). A mutant strain of CC9311, VMUT2, in which the gene for VBPO is disrupted, was also tested. A suite of halomethanes was measured in the headspace above cultures as well as in the culture medium with a purge‐and‐trap method. Monohalomethanes were the most consistently produced molecules among the three strains tested. Additionally, CC9311 produced 301 ± 109 molecules cell −1 d −1 of bromoform (CHBr 3 ) when VBPO activity was detected, while production was not significantly different from zero when VBPO activity was not detected. VBPO activity and CHBr 3 production were only detected when cultures of CC9311 were stirred, which may contribute to the often moderate to weak correlations between CHBr 3 concentration and biological markers in the ocean. No production was seen by VMUT2 or WH8102. These data show that CHBr 3 production rates are dramatically increased with or exclusive to the presence of VBPO, supporting its involvement in CHBr 3 synthesis. This study thus provides genetic evidence that certain strains of marine Synechococcus , under particular conditions, can be a natural source of marine CHBr 3 , which contributes to ozone depletion in the stratosphere.