IRON DEPRIVATION IN CYANOBACTERIA
IRON DEPRIVATION IN CYANOBACTERIA
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DOI：
10.1007/bf02186073
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发表时间：
1994-04-01
影响因子：
3.3
通讯作者：
STRAUS, NA
中科院分区：
文献类型：
--
作者：
FERREIRA, F;STRAUS, NA
铁是几乎所有生物体中电子传输的重要组成部分。它对于蓝藻等光养生物尤其重要，因为完整功能性的光合作用机构需要 22-23 个铁。由于含氧生态系统中铁在中性 pH 值以上的溶解度较低，严重限制了水生微生物对铁的生物利用度，因此蓝细菌和其他微生物已经发展出许多反应来应对缺铁。蓝藻对铁胁迫的反应包括合成一种有效的、基于铁载体的系统来清除铁以及用黄素氧还蛋白替代铁氧还蛋白。蓝细菌的另一个反应涉及光捕获装置的改变，包括出现一种新的、铁胁迫诱导的光系统 II、叶绿素结合蛋白。尽管细胞色素 c-553 在质体蓝蛋白（一种含铜蛋白质）中具有潜在的非铁替代物，但铁胁迫似乎有利于细胞色素 c-553 的利用，因为铁载体也结合铜并形成排除在细胞之外的复合物。本文主要旨在综述活跃生长的蓝藻培养物对铁胁迫条件（其中铁存在但基本上不溶）的分子和生理反应，并将这些反应与铁饥饿区分开来，其中铁的量系统中的铁不足以促进细胞生长。
Iron is an essential component of electron transport in almost all living organisms. It is particularly important to phototrophs like cyanobacteria because 22-23 irons are required for a complete functional photosynthetic apparatus. Since the low solubility of Fe... above neutral pH in oxic ecosystems severely limits the biological availability of iron to aquatic microorganisms, cyanobacteria and other microbes have developed a number of responses to cope with iron deficiency. Cyanobacterial responses to iron stress include the synthesis of an efficient, siderophore-based system to scavenge iron and the substitution of ferredoxin with flavodoxin. An additional response in cyanobacteria involves the alteration of the light-harvesting apparatus that includes the appearance of a new, iron-stress-induced, photosystem II, chlorophyll-binding protein. Although cytochrome c-553 has a potential non-iron-containing replacement in plastocyanin, a copper-containing protein, iron stress appears to favor the utilization of cytochrome c-553 because siderophores also bind copper and form a complex that is excluded from the cell.This paper is intended primarily as a review of molecular and physiological responses of actively growing cyanobacterial cultures to conditions of iron stress, where iron is present but essentially insoluble, and to differentiate these responses from iron starvation, where the amount of iron in the system is not sufficient for cell growth.