Isolation and characterization of photosystem II of Porphyra yezoensis ueda

The thylakoid membranes were isolated and purified from gametophyte of Porphyrayezoensis Ueda (P yezoensis) by sucrose density gradient ultracentrifugation. After R yezoensis gametophyte thylakoid membranes were solubilized with SDS, the photosystem 11 (PSII) particles were isolated and purified. The activity of PSII particles was determined with DCIP (2,6-dichloroindophenol) photoreduction reaction. The composition of purified PSII particles was detected by SDS-PAGE. As a result, seven proteins including 55 kD protein, 47 kD protein, 43 kD protein, 33 kD protein, 31 kD protein, 29 kD protein, and 18 kD protein were found. Compared with PSII particles of higher plants and other algae, they were identified as D1/D2 complex, CP47, CP43, 33 kD protein, D1, D2 and cyt c-550 respectively. Besides, other three new proteins of 20 kD, 16 kD and 14 kD respectively were found. Among these extrinsic proteins, the 16 kD and 14 kD proteins had not been reported previously, and the 20 kD protein was found for the first time in multicellular red algae.

Isolation and characterization of photosystem II from the filamentous sporophyte of Porphyra yezoensis

Thylakoid membranes were isolated and purified from diploid filamentous sporophytes of Porphyra yezoensis Ueda using sucrose density gradient ultracentrifugation (SDGUC). After thylakoid membranes were solubilized with SDS, the photosystem II (PSII) particles with high 2, 6-dichloroindophenol (DCIP) photoreduction activity were isolated by SDGUC. The absorption and fluorescence spectra, DCIP photoreduction activity and oxygen evolution activity of the thylakoid membranes and PSII particles were determined. The polypeptide composition of purified PSII particles was distinguished by SDS-PAGE. Results showed that PSII particles of sporophytes differed from the gametophytes in spectral properties and polypeptide composition. Apart from 55 kDa D1-D2 heterodimer, CP47, CP43, 33 kDa protein was also detected. However, cyt c-550, 20 kDa, 14 kDa and 16 kDa proteins found in PSII particles from gametophytes were not detected in the sporophytes.

The solution properties of phenolphthalein poly(arylether sulfone) .1. The solubility behavior and determination of M-II equations

A series of narrow molecular weight distribution fractions of phenolphthalein polyarylether sulfone(PES-C) had been prepared, The <(M) over bar (w)> of these fractions were determined by conventional light scattering method. The [eta] and the Huggins slope constant k' in DMF, CHCl3 and 1,2-dichloroethane were also determined. The Huggins constants are greater than 0.5 in all of these solvents showing a special solubility behavior. The Mark-Houwink equations of PES-C in these solvents at 25 degrees C are [eta] = 2.79 x 10(-2) <(M) over bar (0.615)(w)> (DMF); [eta] = 3.96 x 10(-2) <(M) over bar (0.58)(w)> (CHCl3); [eta] = 7.40 x 10(-2) <(M) over bar (0.52)(w)> (CH2ClCH2Cl).

ELECTROOXIDATION OF A CHLORIDE COMPLEX OF PLATINUM(II) AT A GLASSY-CARBON ELECTRODE

The electro-oxidation of PtCl42- was studied on a glassy carbon (GC) electrode. A Pt(IV) complex was formed on the electrode surface through coordination to the oxygen atom of an oxide functional group on the electrode, which results in its deactivation. The ferri/ferrocyanide redox couple was used as a probe to examine the activity of the GC electrode. X-ray photoelectron spectroscopy was employed to characterize the platinum on the electrode surface, and showed that the oxidation state of the Pt element changes depending on the electrochemical treatment of GC electrode. The platinum complex on the surface of the GC electrode can be transformed to Pt-0 by cycling the electrode between -0.25 and +1.65 V/SCE in 0.1 M H2SO4 solution. The above procedure can be used to disperse platinum ultramicroparticles on the surface of a GC electrode.

三种红藻光合作用色素系统的比较研究

本研究分为三个部分：1.以坛紫菜（Porphyra haitanesis Chang et Zheng）的叶状体和丝状体为研究对象，比较坛紫菜叶状体和丝状体的光合色素、色素蛋白的组成，并提取纯化藻红蛋白、藻蓝蛋白、藻胆体及类囊体膜和光系统。研究结果表明坛紫菜叶状体和丝状体色素及色素蛋白的含量不同，藻红蛋白是主要的色素蛋白，坛紫菜叶状体和丝状体的藻红蛋白的含量分别为2.9mg藻红蛋白/g鲜重、4.2mg藻红蛋白/g鲜重，这表明坛紫菜叶状体和丝状体藻红蛋白含量丰富，是提取藻红蛋白很好的材料。藻胆体的性质差异不大，但类囊体膜差异显著，从坛紫菜叶状体中分离到了两种不同的类囊体膜带，光系统Ⅰ(PSⅠ)和PSⅡ分别结合在两条类囊体膜带上，但从坛紫菜丝状体中也分离到两条类囊体膜带，它们的光谱性质和蛋白组成相似，仅放氧速率和DCIP活性有差异，从坛紫菜丝状体中我们仅分离到PSⅡ。坛紫菜叶状体PSⅡ有5种外在蛋白(33、20、Cytc 550、15、12kDa蛋白)，而坛紫菜丝状体外在蛋白仅有4条，缺少12kDa蛋白。2. 以在中国江苏部分地区进行了大规模的商业化栽培的突变体条斑紫菜（Porphyra yezoensis Ueda）和野生型条斑紫菜为研究对象，比较其色素及色素蛋白组成、对不能光质的利用率及藻胆体的组成。条斑紫菜和突变型条斑紫菜对不同的光质利用效果有差异，在白光的照射下，野生型紫菜的放氧速率最大，而突变型紫菜在黄光照射下的放氧速率最大。条斑紫菜野生型与突变型色素含量上有明显的差异,突变型紫菜的藻红蛋白含量明显减少而藻蓝蛋白的含量增加。通过杂交的方法证实诱变所获得条斑紫菜突变体为细胞质突变，但是突变型紫菜却发生了由细胞核编码的γ亚基的缺失，这表明突变型紫菜藻红蛋白含量和性质发生了明显的变化。3. 为了找出淡水红藻-深紫美芒藻(Compsopogon coeruleus (Balbis) Montagne)分布狭窄及生物产量低的原因，本文对深紫美芒藻在不同的盐离子浓度下的放氧速率及藻胆体色素组成和结构上进行研究。结果显示：微量的NaCl（0.1mM）促进深紫美芒藻放氧，而深紫美芒藻在较高的NaCl（1、10mM）, NaH2PO4 （0.1、1、10mM）和 NH4NO3（0.1、1、10mM）溶液中却没有检测到氧气的产生。这与深紫美芒藻生长的环境一致即深紫美芒藻生活在低盐浓度、低营养的泉水中。深紫美芒藻的藻胆体是由藻红蛋白、藻蓝蛋白及别藻蓝蛋白组成，上面结合α、β和γ亚基，含有藻红胆素、藻篮胆素，但缺乏缺少藻尿胆素。

SYNTHESIS AND CRYSTAL-STRUCTURE OF THE TRIS(CYCLOPENTADIENYL)PHENYL COMPLEX OF NEODYMIUM, (LI-BULLET-3DME)[(ETA-5-C5H5)3NDC6H5]

(Li.3DME)[eta(5)-C5H5)3NdC6H5], 1 was synthesized by the reaction of NdCl3.2LiCl, 2 equivalents of cyclopentadienylsodium and one equivalent of phenyllithium in THF at -78-degrees-C, and crystallized from THF and DME. The crystal structure of 1 was determined by X-ray diffraction method at -80-degrees-C. The crystal of 1 is triclinic, space group P1BAR with a = 15.752(6), b = 16.232(3), c = 23.038(7) angstrom, alpha = 108.81(2), beta = 93.31(3), gamma = 108.38(2)-degrees, Z = 6 and D = 1.33 g/cm3. Least-squares refinement (5732 observed reflections) led to a final R of 0.053. The complex consists of disconnected ion pairs of (Li.3DME)+ and [(eta(5)-C5H5)3NdC6H5]-. The neodymium atom was connected to three eta(5)-bonded cyclopentadienyls and one sigma-bonded phenyl in a distorted tetrahedral arrangement with Nd-C(sigma-) 2.593(17), 2.613(13) and 2.601(13) angstrom.

Phycobilisomes linker family in cyanobacterial genomes: divergence and evolution

Cyanobacteria are the oldest life form making important contributions to global CO2 fixation on the Earth. Phycobilisomes (PBSs) are the major light harvesting systems of most cyanobacteria species. Recent availability of the whole genome database of cyanobacteria provides us a global and further view on the complex structural PBSs. A PBSs linker family is crucial in structure and function of major light-harvesting PBSs complexes. Linker polypeptides are considered to have the same ancestor with other phycobiliproteins (PBPs), and might have been diverged and evolved under particularly selective forces together. In this paper, a total of 192 putative linkers including 167 putative PBSs-associated linker genes and 25 Ferredoxin-NADP oxidoreductase (FNR) genes were detected through whole genome analysis of all 25 cyanobacterial genomes (20 finished and 5 in draft state). We compared the PBSs linker family of cyanobacteria in terms of gene structure, chromosome location, conservation domain, and polymorphic variants, and discussed the features and functions of the PBSs linker family. Most of PBSs-associated linkers in PBSs linker family are assembled into gene clusters with PBPs. A phylogenetic analysis based on protein data demonstrates a possibility of six classes of the linker family in cyanobacteria. Emergence, divergence, and disappearance of PBSs linkers among cyanobacterial species were due to speciation, gene duplication, gene transfer, or gene loss, and acclimation to various environmental selective pressures especially light.

Comparison between compsopogon coeruleus and porphyra yezoensis in their O-2 evolution rates and phycobilisome composition

In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P yezoensis was R-phycoerythrin containing alpha, beta, and gamma subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of alpha, beta, and gamma subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type.

Structural analysis of peptides of PSII light-harvesting complexes in siphonous green algae, Codium fragile

peptide composition and arrangement of 4 major light-harvesting complexes LHCP1-3 and LHCP3, isolated from siphonous green algae (Codium fragile (Sur.) Hariot.) were investigated. LHCP1 showed five main peptides, 34.4, 31.5, 29.5, 28.2 and 26.5 kD in SDS-PAGE, the 34.4 and 31.5 kD peptides were never found in higher plants. LHCP3 contained the other four kinds of LHCP1 peptides except 34.4 kD, while LHCP3, consisted of only 28.2 and 26.5 kD peptides. We found that 34.4, 28.2 and 26.5 kD peptides were easy to decompose from LHCP1 when subjected to SDS-PACE without pretreatment. They might be located at the exterior of LHCP1, while the 31.5 and 29.5 kD peptides were at the central part. The 28.2 and 26.5 kD peptides often occurred in CPa, the center complex of PS II. They are possibly the LHC II peptides tightly associated with CC II. According to the results described above, a peptide map of LHCP1 was sketched.