title: Supramolecular architecture of photosynthetic membrane in red algae in response to nitrogen starvation.
abstract: The availability of nitrogen is one of the most important determinants that can limit the growth of photosynthetic organisms including plants and algae; however, direct observations on the supramolecular architecture of photosynthetic membranes in response to nitrogen stress are still lacking. Red algae are an important evolutionary group of algae which contain phycobilisomes (PBSs) on their thylakoid membranes, as do cyanobacteria. PBSs function not only as light-harvesting antennae but also as nitrogen storage. In this report, alterations of the supramolecular architecture of thylakoid membranes from red alga Porphyridium cruentum during nitrogen starvation were characterized. The morphology of the intact thylakoid membrane was observed to be round vesicles. Thylakoid membranes were reduced in content and PBSs were degraded during nitrogen starvation. The size and density of PBSs were both found to be reduced. PBS size decreased by less than one-half after 20days of nitrogen starvation, but their hemispherical morphology was retained. The density of PBSs on thylakoid membranes was more seriously affected as time proceeded. Upon re-addition of nitrogen led to increasing of PBSs on thylakoid membranes. This work reports the first direct observation on alterations in the supramolecular architecture of thylakoid membranes from a photosynthetic organism in response to nitrogen stress.
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Long-Sheng
authors.initials: LS
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China. Electronic address: suhn@sdu.edu.cn.
authors.forename: Hai-Nan
authors.initials: HN
authors.lastname: Su
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Li
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Lu-Ning
authors.initials: LN
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Xi-Ying
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China.
authors.forename: Bai-Cheng
authors.initials: BC
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Institute of Marine Science and Technology, Shandong University, Jinan 250100, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
authors.forename: Yu-Zhong
authors.initials: YZ
authors.lastname: Zhang
mesh_terms: D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure*; D009584:Nitrogen / Q000172:deficiency*; D000461:Rhodophyta / Q000378:metabolism / Q000648:ultrastructure*; D013312:Stress, Physiological; D020524:Thylakoids / Q000378:metabolism / Q000648:ultrastructure*
chemical_list: D009584:Nitrogen
keywords: Atomic force microscopy; Nitrogen starvation; Photosynthesis; Phycobilisome; Red algae