科研之友
微信
新浪微博
Facebook
分享链接
摘要
The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies being distinguished: strategy I involves the induction of a Fe(III)-chelate reductase (ferrireductase) along with Fe(II) or Fe(III) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine, plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the green alga Tetraselmis suecica. Short term radio-iron uptake studies indicate that iron is taken up by Tetraselmis in a time and concentration dependent manner consistent with an active transport process. Based on inhibitor and other studies it appears that a reductive-oxidative pathway such as that found in yeast and the green alga Chlamydomonas reinhardtii is likely. Upon long term exposure to Fe-57 we have been able, using a combination of Mossbauer and X-ray absorption spectroscopies, to identify three metabolites. The first exhibits Mossbauer parameters typical of a [Fe4S4](2+) cluster and which accounts for approximately 10% of the total intracellular iron pool. The second displays a spectrum typical of a [(FeO6)-O-II] system accounting for approximately 2% of the total pool. The largest component (ca. 85+%) consists of polymeric iron-oxo mineral species with parameters between that of the crystalline ferrihydrite core of animal ferritins and the amorphous hydrated ferric phosphate of bacterial and plant ferritins.
- 出版日期2012-11
