Topography and functional information of plasma membrane

doi:10.1007/s11427-008-0007-y

CORC > 化学研究所 > 中国科学院化学研究所

	Topography and functional information of plasma membrane
	Sun, DeLan 1; Chen, JianMin 1; Song, YanMei 1; Zhu, ChuanFeng 2; Pan, GeBo 2; Wan, LiJun 2
刊名	SCIENCE IN CHINA SERIES C-LIFE SCIENCES
	2008-02-01
卷号	51 期号:2 页码:95-103
关键词	Atomic Force Microscope Winter Wheat Protoplast Plasma Membrane Surface Membrane Protein Invaginated Pits
ISSN号	1006-9305
DOI	10.1007/s11427-008-0007-y
英文摘要	By using atomic force microscope (AFM), the topography and function of the plasmalemma surface of the isolated protoplasts from winter wheat mesophyll cells were observed, and compared with dead protoplasts induced by dehydrating stress. The observational results revealed that the plasma membrane of living protoplasts was in a state of polarization. Lipid layers of different cells and membrane areas exhibited distinct active states. The surfaces of plasma membranes were unequal, and were characterized of regionalisation. In addition, lattice structures were visualized in some regions of the membrane surface. These typical structures were assumed to be lipid molecular complexes, which were measured to be 15.8 +/- 0.09 nm in diameter and 1.9 +/- 0.3 nm in height. Both two-dimensional and three-dimensional imaging showed that the plasmalemma surfaces of winter wheat protoplasts were covered with numerous protruding particles. In order to determine the chemical nature of the protruding particles, living protoplasts were treated by proteolytic enzyme. Under the effect of enzyme, large particles became relatively looser, resulting that their width was increased and their height decreased. The results demonstrated that these particles were likely to be of protein nature. These protein particles at plasmalemma surface were different in size and unequal in distribution. The diameter of large protein particles ranged from 200 to 440 nm, with a central micropore, and the apparent height of them was found to vary from 12 to 40 nm. The diameter of mid-sized protein particles was between 40-60 nm, and a range of 1.8-5 nm was given for the apparent height of them. As for small protein particles, obtained values were 12-40 nm for their diameter and 0.7-2.2 nm for height. Some invaginated pits were also observed at the plasma membrane. They were formed by the endocytosis of protoplast. Distribution density of them at plasmalemma was about 16 pits per 15 mu m(2). According to their size, we classified the invaginated pits into two types-larger pits measuring 139 nm in diameter and 7.2 nm in depth, and smaller pits measuring 96 nm in diameter and 2.3 nm in depth. On dehydration-induced dead protoplasts, the degree of polarization of plasma membranes decreased. Lipid molecular layers appeared relatively smooth, and the quantity of integral proteins reduced a lot. Invaginated pits were still detectable at the membrane surface, but due to dehydration-induced protoplast contraction, the orifice diameter of pits reduced, and their depth increased. Larger pits averagely measuring 47.4 nm in diameter and 31.9 nm in depth, and smaller pits measuring 26.5 nm in diameter and 43 nm in depth at average. The measured thickness of plasma membranes of mesophyll cells from winter wheat examined by AFM was 6.6-9.8 nm, thicker in regions covered with proteins.
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000252876000001
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/65075]
专题	中国科学院化学研究所
通讯作者	Sun, DeLan
作者单位	1.Chinese Acad Sci, Inst Bot, Key Lab Photosynthesis & Environm Mol Physiol, Beijing 100093, Peoples R China 2.Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Sun, DeLan,Chen, JianMin,Song, YanMei,et al. Topography and functional information of plasma membrane[J]. SCIENCE IN CHINA SERIES C-LIFE SCIENCES,2008,51(2):95-103.
APA	Sun, DeLan,Chen, JianMin,Song, YanMei,Zhu, ChuanFeng,Pan, GeBo,&Wan, LiJun.(2008).Topography and functional information of plasma membrane.SCIENCE IN CHINA SERIES C-LIFE SCIENCES,51(2),95-103.
MLA	Sun, DeLan,et al."Topography and functional information of plasma membrane".SCIENCE IN CHINA SERIES C-LIFE SCIENCES 51.2(2008):95-103.