Dimethylsulphoniopropionate (DMSP), DMSP-lyase activity (DLA) and dimethylsulphide (DMS) in 10 species of coccolithophore
Dimethylsulphoniopropionate (DMSP), DMSP-lyase activity (DLA) and dimethylsulphide (DMS) in 10 species of coccolithophore
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DOI：
10.3354/meps08596
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发表时间：
2010-01-01
影响因子：
2.5
通讯作者：
Malin, Gill
中科院分区：
文献类型：
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作者：
Franklin, Daniel J.;Steinke, Michael;Malin, Gill
对10种球石藻进行了批量培养，研究了二甲基磺酰丙酸酯（DMSP）用量（pg DMSP细胞（-1））、细胞内DMSP浓度（mM）、体内和体外DMSP裂解酶活性（DLA）和二甲基硫化物（DMS）浓度。选择的物种跨越了存在于颗石藻中的系统发育和大小范围。我们的总体目标是检验被认为是“模式”球石藻物种的埃米利亚·赫胥利（Emiliania huxleyi）是否在DMSP、DLA和DMS方面具有代表性，因为其他球石藻对温带和热带水域的浮游植物生物量和碳通量有重大贡献。DMSP在所有物种中均被发现，并且DMSP配额与细胞体积显著相关，反映了DMSP作为相容溶质在该群体中的基本生理作用。这种DMSP配额-细胞体积关系可用于计算不同物种对总DMSP的相对贡献。降低养分利用率（在养分浓度降低10倍的条件下分批生长）对DMSP配额没有显著影响。与DMSP相反，DLA和DMS浓度在不同物种间存在差异。cocolithophore DLA仅在E. huxleyi和Gephyrocapsa oceanica中发现，我们发现DLA仅限于这两个亲缘关系密切的物种。如果DLA仅限于一个子集的颗石藻，那么这些物种更有可能直接在海洋中排放DMS。我们的研究结果表明，在球石藻形成稳定种群的生态系统中，除赫胥利外的其他物种可以对颗粒DMSP库做出重大贡献，从而对微生物环的DMSP潜在可用量做出重大贡献。
We investigated dimethylsulphoniopropionate (DMSP) quota (pg DMSP cell(-1)), intracellular DMSP concentration (mM), in vitro and in vivo DMSP-lyase activity (DLA) and dimethylsulphide (DMS) concentration in batch cultures of 10 species of coccolithophore. Species were chosen to span the phylogenetic and size range that exists within the coccolithophores. Our overall objective was to examine if Emiliania huxleyi, considered a 'model' coccolithophore species, is representative in terms of DMSP, DLA and DMS, because other coccolithophores contribute substantially to phyto-plankton biomass and carbon fluxes in temperate and tropical waters. DMSP was found in all species, and DMSP quotas correlated significantly with cell volume, reflecting the fundamental physiological role of DMSP as a compatible solute in this group. This DMSP quota-cell volume relationship can be used to calculate the relative contribution of different species to total DMSP. Lowered nutrient availability (batch growth at a 10-fold lower nutrient concentration) did not significantly affect DMSP quota. In contrast to DMSP, DLA and DMS concentration were variable between the subset of species investigated. Coccolithophore DLA is known only in E. huxleyi and Gephyrocapsa oceanica, and we found DLA to be restricted to these closely related species. If DLA is restricted to a subset of coccolithophores, then those species are more likely to emit DMS directly in the sea. Our results indicate that in ecosystems where coccolithophores form stable populations, species other than E. huxleyi can make significant contributions to the particulate DMSP pool and hence to the amount of DMSP potentially available to the microbial loop.