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DOI | 10.1073/pnas.1908165116 |
Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean | |
Cornejo-Castillo, Francisco M.; Zehr, Jonathan P. | |
2019 | |
发表期刊 | PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA |
ISSN | 0027-8424 |
出版年 | 2019 |
卷号 | 116期号:37页码:18269-18271 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | Cyanobacterial diazotrophs are considered to be the most important source of fixed N-2 in the open ocean. Biological N-2 fixation is catalyzed by the extremely O-2-sensitive nitrogenase enzyme. In cyanobacteria without specialized N-2-fixing cells (heterocysts), mechanisms such as decoupling photosynthesis from N-2 fixation in space or time are involved in protecting nitrogenase from the intracellular O-2 evolved by photosynthesis. However, it is not known how cyanobacterial cells limit O-2 diffusion across their membranes to protect nitrogenase in ambient O-2-saturated surface ocean waters. Here, we explored all known genomes of the majormarine cyanobacterial lineages for the presence of hopanoid synthesis genes, since hopanoids are a class of lipids that might act as an O-2 diffusion barrier. We found that, whereas all non-heterocyst-forming cyanobacterial diazotrophs had hopanoid synthesis genes, none of the marine Synechococcus, Prochlorococcus (non-N-2-fixing), and marine heterocyst-forming (N-2-fixing) cyanobacteria did. Finally, we conclude that hopanoid-enriched membranes are a conserved trait in non-heterocyst-forming cyanobacterial diazotrophs that might lower the permeability to extracellular O-2. This membrane property coupled with high respiration rates to decrease intracellular O-2 concentration may therefore explain how non-heterocyst-forming cyanobacterial diazotrophs can fix N-2 in the fully oxic surface ocean. |
英文关键词 | oxygen diffusion barrier hopanoid lipids nitrogen fixation marine cyanobacteria |
领域 | 地球科学 ; 气候变化 ; 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000485145400023 |
WOS关键词 | MARINE CYANOBACTERIUM ; OXYGEN ; PROCHLOROCOCCUS ; TRICHODESMIUM |
WOS类目 | Multidisciplinary Sciences |
WOS研究方向 | Science & Technology - Other Topics |
URL | 查看原文 |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/205172 |
专题 | 地球科学 资源环境科学 气候变化 |
作者单位 | Univ Calif Santa Cruz, Dept Ocean Sci, Santa Cruz, CA 95064 USA |
推荐引用方式 GB/T 7714 | Cornejo-Castillo, Francisco M.,Zehr, Jonathan P.. Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2019,116(37):18269-18271. |
APA | Cornejo-Castillo, Francisco M.,&Zehr, Jonathan P..(2019).Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,116(37),18269-18271. |
MLA | Cornejo-Castillo, Francisco M.,et al."Hopanoid lipids may facilitate aerobic nitrogen fixation in the ocean".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 116.37(2019):18269-18271. |
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