Acclimation to low [CO2] by an inorganic carbon-concentrating mechanism in Cyanophora paradoxa
Acclimation to low [CO2] by an inorganic carbon-concentrating mechanism in Cyanophora paradoxa
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DOI：
10.1111/j.1365-3040.2007.01715.x
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发表时间：
2007-11-01
影响因子：
7.3
通讯作者：
Loeffelhardt, W.
中科院分区：
文献类型：
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作者：
Burey, S. C.;Poroyko, V.;Loeffelhardt, W.
蓝囊藻含有蓝色素，具有原核分裂特征的质体，如肽聚糖壁和中心蛋白质包涵体。虽然该中心体包括大部分的酶核酮糖1，5-二磷酸羧化酶/氧合酶Rubisco），但C. paradox悖论has only been hypothesized假设.在这里，我们提出的生理数据支持CCM：CO2交换活性以及对无机碳的表观亲和力被发现增加CO2限制应力下。此外，表达序列标签（EST）的C。从两个cDNA文库中获得了paradoxa，一个来自在高[CO2]条件下生长的细胞，一个来自在低[CO2]条件下生长的细胞。从2378个cDNA序列组装的cDNA微阵列平台显示，142个基因显着响应从高到低[CO2]的转变。基因表达的趋势与莱茵衣藻和蓝藻集胞藻6803（两者均具有CCM）的报告结果相当。在受[CO2]调控的基因中，在C. paradoxa，可能在CCM中起作用。这些结果和多面体外观的中央机构进一步支持的假说，一个独特的“真核羧基”的蓝藻。
The glaucocystophyte Cyanophora paradoxa contains cyanelles, plastids with prokaroytic features such as a peptidoglycan wall and a central proteinaceous inclusion body. While this central body includes the majority of the enzyme ribulose 1,5-bisphosphate carboxylase/oxgenase Rubisco), the presence of a carbon-concentrating mechanism (CCM) in C. paradoxa has only been hypothesized. Here, we present physiological data in support of a CCM: CO2 exchange activity as well as apparent affinity against inorganic carbon were found to increase under CO2-limiting stress. Further, expressed sequence tags (ESTs) of C. paradoxa were obtained from two cDNA libraries, one from cells grown in high [CO2] conditions and one from cells grown under low [CO2] conditions. A cDNA microarray platform assembled from 2378 cDNA sequences revealed that 142 genes significantly responded to a shift from high to low [CO2]. Trends in gene expression were comparable to those reported for Chlamydomonas reinhardtii and the cyanobacterium Synechocystis 6803, both possessing a CCM. Among genes regulated by [CO2], transcripts were identified encoding carbonic anhydrases (CAs), Rubisco activase and a putative bicarbonate transporter in C. paradoxa, likely functionally involved in the CCM. These results and the polyhedric appearance of the central body further support the hypothesis of a unique 'eukaryotic carboxysome' in Cyanophora.