Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms 1
Use of exogenous glycine betaine and its precursor choline as osmoprotectants in Antarctic sea‐ice diatoms 1
复制标题
外源甘氨酸甜菜碱及其前体胆碱作为南极海冰硅藻渗透保护剂的用途1
DOI：
10.1111/jpy.12839
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发表时间：
2019
影响因子：
2.9
通讯作者：
Valentin, K.
中科院分区：
文献类型：
--
作者：
Torstensson, Anders;Young, Jodi N.;Carlson, Laura T.;Ingalls, Anitra E.;Deming, Jody W.;Valentin, K.
在海冰的季节性冻结和融化期间所经历的宽盐度范围可能限制了许多生物过程。微生物通常通过吸收、产生和释放相容溶质来防止盐度波动。然而，关于甘氨酸甜菜碱（GBT）的使用或命运知之甚少，甘氨酸甜菜碱是最常见的相容溶质之一，在面临盐度变化的海冰硅藻中。我们量化了细胞内的浓度，并使用[14C]标记的化合物来追踪三种南极海冰硅藻（snitzschia lecointei,Naviculacf）中含氮渗透物GBT及其前体胆碱的吸收和归宿。在- 1°C下，白蜡蒿和白蜡蒿。实验表明，这些硅藻具有有效的GBT转运体，但对胆碱的吸收较少。两种化合物都没有呼吸。摄取GBT可以保护细胞免受高渗休克，并减少细胞外多糖inN的产生。低渗休克后残留GBT的85%被lecointeiccells释放。海冰硅藻快速清除和释放相容溶质的能力可能是在盐度急剧波动中生存的重要策略。相容溶质的释放和再循环可能在海冰半封闭盐水中藻-细菌相互作用和氮循环中起重要作用。
Wide salinity ranges experienced during the seasonal freeze and melt of sea ice likely constrain many biological processes. Microorganisms generally protect against fluctuating salinities through the uptake, production, and release of compatible solutes. Little is known, however, about the use or fate of glycine betaine (GBT hereafter), one of the most common compatible solutes, in sea‐ice diatoms confronted with shifts in salinity. We quantified intracellular concentrations and used [14C]‐labeled compounds to track the uptake and fate of the nitrogen‐containing osmolyte GBT and its precursor choline in three Antarctic sea‐ice diatomsNitzschia lecointei,Naviculacf.perminuta,andFragilariopsis cylindrusat −1°C. Experiments show that these diatoms have effective transporters for GBT, but take up lesser amounts of choline. Neither compound was respired. Uptake of GBT protected cells against hyperosmotic shock and corresponded with reduced production of extracellular polysaccharides inN. lecointeicells, which released 85% of the retained GBT following hypoosmotic shock. The ability of sea‐ice diatoms to rapidly scavenge and release compatible solutes is likely an important strategy for survival during steep fluctuations in salinity. The release and recycling of compatible solutes may play an important role in algal–bacterial interactions and nitrogen cycling within the semi‐enclosed brines of sea ice.