藻类通过与细菌的共生关系获得维生素B12
Martin T Croft1, Andrew D Lawrence, Evelyne Raux-Deery
1Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
Nature
|November 4, 2005
概括
许多藻类需要维生素B12 (科巴胺) 才能生长,主要是用于甲氨酸合成酶. 这种维生素B12附属性进化了多次,细菌可能是来源,这表明了关键的藻类-细菌共生.
科学领域:
- 生物化学 生物化学
- 海洋生物学 海洋生物学
- 微生物学 微生物学
背景情况:
- 维生素B12 (科巴胺) 对人类健康至关重要,但由于缺乏依赖性酶,植物中缺少.
- 藻类与植物不同,可能富含维生素B12,但其在这些生物体中的作用和来源尚不清楚.
- 超过一半的被调查的藻类物种 (326种中有171种) 是可巴拉胺辅食性,需要外部的维生素B12来生长.
研究的目的:
- 阐明维生素B12在藻类中的代谢作用.
- 调查藻类王国中可巴胺辅性的进化起源.
- 为了确定藻类的维生素B12来源.
主要方法:
- 对326种藻类进行了调查,以确定对生长的科巴拉的需求.
- 分析了维生素B12在藻类代谢中的功能.
- 研究了可巴胺辅助性变化的进化模式.
主要成果:
- 维生素B12主要作为藻类中 metionin合成酶的辅因子起作用.
- 在藻类中,可巴胺辅性已经独立地进化了多次,这可能是由于维生素B12独立的氨酸合成酶的丧失.
- 细菌共生体被确定为辅食藻类维生素B12的可能来源.
结论:
- 维生素B12在藻类中的主要作用是作为甲氨酸合成酶的辅因子.
- 藻类中广泛存在的可巴胺辅助性突出显示了由酶损失驱动的融合进化.
- 藻类和细菌之间存在重要的共生关系,用于维生素B12的获取.
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