Light Quantity Affects the Regulation of Cell Shape in Fremyella diplosiphon
Light Quantity Affects the Regulation of Cell Shape in Fremyella diplosiphon
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光量影响双管芙蕾菌细胞形状的调控
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
B. Montgomery
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作者：
B. Pattanaik;Melissa J. Whitaker;B. Montgomery
在一些蓝细菌中，环境光的颜色或普遍波长会影响捕光复合物的蛋白质或色素组成。在某些情况下，浅色或浅色质量会影响细胞形态。色素沉着变化的意义与优化光合作用的光吸收密切相关，而光质量依赖的细胞形态变化的意义则不太清楚。在自然的水生环境中，光的质量和强度在水柱的不同深度同时变化。因此，我们假设，形态的变化，也已归因于可用光的普遍波长的差异可能在很大程度上与光强度的变化。Fremyella diplosiphon在色素沉着和形态学上表现出高度可重复的光依赖性变化。红光（RL）下，F.由于在捕光复合物或藻胆体（PBS）中积累了高水平的藻蓝蛋白（一种吸收RL的色素），diplosiphon细胞的颜色为蓝绿色，并且细胞的形状短而圆。相反，在绿色光（GL）下，F.由于吸收GL的藻红蛋白在PBS中的积累，双虹吸管细胞是红色的，并且是较长的和砖形的。GL在水柱的较低深度处富集，其中总的光水平也降低，即，至水面强度的10%或更低。我们假设，较长的细胞在低光强度下，在不断增加的深度在水柱，这通常也是丰富的绿色波长，与更高水平的总光合色素类囊体膜。为了验证这一假设，我们种植了F。在GL强度增加的情况下，观察细胞的长度是否由于降低的压力而减少，以保持较大的细胞和在高光强度下相关的增加的光合膜容量，而与是否是绿色波长的光无关。
In some cyanobacteria, the color or prevalent wavelengths of ambient light can impact the protein or pigment composition of the light-harvesting complexes. In some cases, light color or quality impacts cellular morphology. The significance of changes in pigmentation is associated strongly with optimizing light absorption for photosynthesis, whereas the significance of changes in light quality-dependent cellular morphology is less well understood. In natural aquatic environments, light quality and intensity change simultaneously at varying depths of the water column. Thus, we hypothesize that changes in morphology that also have been attributed to differences in the prevalent wavelengths of available light may largely be associated with changes in light intensity. Fremyella diplosiphon shows highly reproducible light-dependent changes in pigmentation and morphology. Under red light (RL), F. diplosiphon cells are blue-green in color, due to the accumulation of high levels of phycocyanin, a RL-absorbing pigment in the light-harvesting complexes or phycobilisomes (PBSs), and the shape of cells are short and rounded. Conversely, under green light (GL), F. diplosiphon cells are red in color due to accumulation of GL-absorbing phycoerythrin in PBSs, and are longer and brick-shaped. GL is enriched at lower depths in the water column, where overall levels of light also are reduced, i.e., to 10% or less of the intensity found at the water surface. We hypothesize that longer cells under low light intensities at increasing depths in the water column, which are generally also enriched in green wavelengths, are associated with greater levels of total photosynthetic pigments in the thylakoid membranes. To test this hypothesis, we grew F. diplosiphon under increasing intensities of GL and observed whether the length of cells diminished due to reduced pressure to maintain larger cells and the associated increased photosynthetic membrane capacity under high light intensity, independent of whether it is light of green wavelengths.