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Siderophores from Marine Microorganisms and Their Applications 总被引:4,自引:1,他引:3
LIJunfeng CHIZhenming 《中国海洋大学学报(英文版)》2004,3(1):40-47
1 Introduction Ironisanessentialelementwhichisdifficulttoob tainduetoitslowsolubilityunderthephysiologicalconditions ,anditisalsothemostimportanttransitionmetalionfornearlyalllivingsystems.Manypatho genicbacteriausuallyobtainironfromtheiron bind ingprot… 相似文献
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The excretion of siderophores and the reduction of organic iron-complexes at the cell surface are common reactions of terrestrial plants, fungi and bacteria in response to low availability of iron. However, there is much less evidence for the use of these strategies by marine phytoplankton. It has been argued that siderophore excretion is inefficient in an aquatic environment due to rapid diffusion. This study examines how diffusion and chemical reactions in the microenvironment of a phytoplankton cell influence the efficiency of both strategies to increase the bioavailability of iron and to reduce iron stress. A numerical model of the cell surroundings is presented that calculates the concentration distribution for different iron species and allows to study the effect of siderophores or surface reductases. It calculates the efficiency of these mechanisms, defined as the quotient between the increase in iron uptake rate and the excretion rate of siderophores or electrons, needed to obtain this increase. The dependence of this efficiency on rates of iron coordination reactions, on diffusivity, and on the kinetics of iron uptake is discussed with the aid of some analytical calculations. 相似文献
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