Nutrient regulation of bacterial production and ectoenzyme activities in the subtropical North Pacific Ocean
Nutrient regulation of bacterial production and ectoenzyme activities in the subtropical North Pacific Ocean
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DOI：
10.1016/s0967-0645(00)00158-2
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发表时间：
2001-01-01
影响因子：
3
通讯作者：
Karl, DM
中科院分区：
文献类型：
--
作者：
Donachie, SP;Christian, JR;Karl, DM
细菌与开放海洋中的溶解有机物(DOM)之间的相互作用知之甚少。虽然某些化合物可能会不成比例地调节异养活性，但人们对其潜在的过程知之甚少。通过1996年12月至1998年4月的10次航行，我们研究了ALOHA站(北纬22度45‘度，西经158度)0.8微米过滤海水(FSW)培养中异养(非色素)细菌细胞产量、每细胞α-和β-葡萄糖苷酶和亮氨酸氨基肽酶(LAP酶)活性以及(14)C-葡萄糖吸收对有机和无机营养添加(葡萄糖、单一氨基酸、NH(4)(+)、NO(3)(-))的响应。添加葡萄糖(1um)或单一外源氮源(1um N)的FSW与单独FSW相比，细菌产量没有显著变化。此外，添加有机氮和无机氮、有机氮加葡萄糖、无机氮加葡萄糖的FSW对异养细菌产量无显著影响。然而，添加外源葡萄糖(0.38um)+1um无机氮(NH(4)(+))的FSW的细胞产量明显高于单独FSW、添加葡萄糖的FSW和以1um N为氨基酸(组氨酸、酪氨酸、亮氨酸)的FSW。添加葡萄糖、葡萄糖和氨基酸的搅拌搅拌槽异养细菌产量与单独搅拌搅拌槽相比差异不显著。当外源葡萄糖+NH(4)(+)或NO(3)(-)时，细胞特异性LAP活性显著高于未修饰的FSW，而氨基酸、葡萄糖、NH(4)(+)或NO(3)(-)单独作用很小或没有影响。α-葡萄糖苷酶活性随外源组氨酸和酪氨酸的添加而增加。我们的结果表明，Aloha站的异养活性可以由特定化合物的丰度来调节，而不考虑它们的总浓度。Aloha站的细菌之间可能同时存在营养缺乏症和从葡萄糖合成细胞蛋白的现象，而且胞外酶表达的调节与产品的可用性无关。(C)2001爱思唯尔科学有限公司。保留所有权利。
Interactions between Bacteria and dissolved organic matter (DOM) in the open ocean are poorly understood. While it is likely that particular compounds may disproportionately regulate heterotrophic activity, very little is known about the underlying processes. Through 10 cruises between December 1996 and April 1998 we investigated how heterotrophic (non-pigmented) Bacteria cell production, per cell alpha- and beta -glucosidase and leucine aminopeptidase (LAPase) activities, and (14)C-glucose uptake in 0.8 mum filtered seawater (fsw) cultures at Station ALOHA (22 degrees 45 'N, 158 degreesW) responded to organic and inorganic nutrient additions (glucose, single amino acids, NH(4)(+), NO(3)(-)). Bacterial cell production did not change significantly in fsw with glucose (1 muM) or single exogenous N sources (1 muM N) compared to that in fsw alone. Furthermore, there was no significant difference in heterotrophic bacterial cell production in fsw amended with organic or inorganic N, nor between that in fsw with organic N and glucose, or inorganic N and glucose. Cell production did increase significantly, however, in fsw with exogenous glucose (0.38 muM) plus 1 muM inorganic N (NH(4)(+)) relative to that in fsw only, in fsw with glucose, and in fsw with 1 muM N as amino acids (His, Tyr, Leu). There was no significant difference between heterotrophic bacterial cell production in fsw with glucose, glucose plus amino acids, and that in fsw alone. Cell-specific LAPase activity increased significantly relative to that in unamended fsw when exogenous glucose plus NH(4)(+) or NO(3)(-) were provided, but amino acids, glucose, NH(4)(+) or NO(3)(-) alone had little or no effect. alpha -Glucosidase activity tended to increase with exogenous His and Tyr additions. Our results suggest that heterotrophic activity at Station ALOHA can be regulated by the abundance of particular compounds, regardless of their total concentrations. It appears that auxotrophy and de novo synthesis of cell protein from glucose may coexist among Bacteria at Station ALOHA, and that regulation of ectoenzyme expression is independent of product availability. (C) 2001 Elsevier Science Ltd. All rights reserved.