REARRANGEMENT OF LIGHT-HARVESTING BACTERIOCHLOROPHYLL HOMOLOGS AS A RESPONSE OF GREEN SULFUR BACTERIA TO LOW-LIGHT INTENSITIES
REARRANGEMENT OF LIGHT-HARVESTING BACTERIOCHLOROPHYLL HOMOLOGS AS A RESPONSE OF GREEN SULFUR BACTERIA TO LOW-LIGHT INTENSITIES
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DOI：
10.1007/bf00032232
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发表时间：
1995-07-01
影响因子：
3.7
通讯作者：
GARCIAGIL, LJ
中科院分区：
文献类型：
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作者：
BORREGO, CM;GARCIAGIL, LJ
对两种含BChl c的绿色绿色硫细菌（Chlorobium limicola和C. chlorovibrioides）和2种棕色的BChl e（C. phaeobacteroides和C. phaeovibrioides）在不同光强度下孵育。所有的物种都对从50到1 μ Einstein（E）m（-2）s（-1）的光强度的降低做出了反应，增加了捕光色素、细菌叶绿素和类胡萝卜素的特定含量。在临界光强度（0.5 ~ 0.1 μ E·m（-2）·s（-1））下，只有棕色的绿球藻能够生长，但比生长速率很低（0.002天（-1）mg prot（-1））。发现法尼基-细菌叶绿素同系物的相对含量变化很大，特别是BChl e（1）和BChl e（4），它们分别被初步鉴定为[M，E]和[I，E] BChl（F）e。当光照强度从50 μ E m（-2）s（-1）降低到0.1 μ E m（-2）s（-1）时，前者几乎完全丧失，而后者则从7.2%增加到38.4%和从13.6%增加到42.0%。phaeobacteroides和C. phaeovibrioides。棕色物种的叶绿体内的高度烷基化的色素分子的含量的增加被解释为一种生理机制，以提高向反应中心的能量转移的效率。本研究为了解棕色植物对极弱光适应的生理基础提供了线索。
The pigment composition of two species of green-colored BChl c-containing green sulfur bacteria (Chlorobium limicola and C. chlorovibrioides) and two species of brown-colored BChl e-containing ones (C. phaeobacteroides and C. phaeovibrioides) incubated at different light intensities have been studied. All species responded to the reduction of light intensity from 50 to 1 mu Einstein(E) m(-2) s(-1) by an increase in the specific content of light harvesting pigments, bacteriochlorophylls and carotenoids. At critical light intensities (0.5 to 0.1 mu E m(-2) s(-1)) only brown-colored chlorobia were able to grow, though at low specific rates (0.002 days(-1) mg prot(-1)). High variations in the relative content of farnesyl-bacteriochlorophyll homologues were found, in particular BChl e(1) and BChl e(4), which were tentatively identified as [M, E] and [I, E] BChl(F) e, respectively. The former was almost completely lost upon reduction of light intensity from 50 to 0.1 mu E m(-2) s(-1), whereas the latter increased from 7.2 to 38.4% and from 13.6 to 42.0% in C. phaeobacteroides and C. phaeovibrioides, respectively. This increase in the content of highly alkylated pigment molecules inside the chlorosomes of brown species is interpreted as a physiological mechanism to improve the efficiency of energy transfer towards the reaction center. This study provides some clues for understanding the physiological basis of the adaptation of brown species to extremely low light intensities.