The donor side of photosystem II is impaired in a Cd2+-tolerant mutant strain of the unicellular green algaChlamydomonas reinhardtii
The donor side of photosystem II is impaired in a Cd2+-tolerant mutant strain of the unicellular green algaChlamydomonas reinhardtii
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DOI：
10.1078/0176-1617-00705
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发表时间：
2002
影响因子：
4.3
通讯作者：
J. Voigt;K. Nagel
中科院分区：
文献类型：
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作者：
J. Voigt;K. Nagel
总结发现单细胞绿色衣藻耐镉突变株的生长在光自养条件下受损，但在兼养条件下不受损。与野生型细胞相比，光合自养生长的突变体的氧释放大大降低，并且需要更高的光子注量率用于光补偿氧消耗/产生和最大氧释放。在乙酸盐存在下生长时，莱茵衣藻细胞产氧能力下降，不通气。在这些条件下生长的野生型细胞在转移到光自养条件后立即显示出相当低但显著的氧释放。这种残留的氧气生产完全抑制在乙酸盐的存在下，显然是由于乙酸盐抑制的水裂解复合物。然而，在我们的耐镉突变株的情况下，即使在乙酸盐的存在下也测量了残余氧的产生。去除乙酸盐后，由耐镉突变株的氧释放增加到比野生型细胞测得的更高的速率，但需要相当高的光子注量率的光补偿的氧消耗/生产和最大的氧释放。羟胺引起的荧光水平的更强的降低进一步证实了光系统II的供体侧在我们的耐镉突变株中受到影响的结论。
Summary Growth of a cadmium-tolerant mutant strain of the unicellular green alga Chlamydomonas reinhardtii was found to be impaired under photoautrotrophic, but not under mixotrophic conditions. As compared to wild-type cells, oxygen evolution by the photoautotrophically grown mutant was considerably decreased and higher photon fluence rates were required both for light compensation of oxygen consumption/production and maximal oxygen evolution. The capability for oxygen production was decreased in Chlamydomonas reinhardtii cells when grown in the presence of acetate without aeration. Wild-type cells grown under these conditions showed a rather low but significant oxygen evolution immediately after transfer to photoautotrophic conditions. This residual oxygen production was completely suppressed in the presence of acetate, obviously due to acetate inhibition of the water-splitting complex. In the case of our cadmium-tolerant mutant strain, however, residual oxygen production was measured even in the presence of acetate. After removal of acetate, oxygen evolution by the cadmium-tolerant mutant strain was increased to higher rates than measured for wild-type cells, but considerably higher photon fluence rates were required both for light compensation of oxygen consumption/production and maximal oxygen evolution. The conclusion that the donor side of photosystem II is affected in our cadmium-tolerant mutant strain was further corroborated by a stronger decrease of the fluorescence level caused by hydroxylamine.