“8455”小麦植株化学成分与麦蚜（长管蚜、二叉蚜）种群消长的关系

通过对两种肥力条件下的“8455”小麦植株化学成分与麦长管蚜和麦二叉蚜种群消长关系的研究与分析,结果表明可溶性糖、含钾量、含水量是影响麦二叉蚜种群消长的主要因子,胱氨酸是影响麦长管蚜种群消长的主要因子。     

麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报

麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报张玉铭,马永清（中国科学院石家在农业现代化研究所,０５００２１）ＡｌｌｅｌｏｐａｔｈｉｃＥｆｆｅｃｔｏｆＷｈｅａｔＳｔｒａｗＭｕｌｃｈｉｎｇｏｎＳｅｅｄｌｉｎｇＧｒｏｗｔｈａｎｄＤｅｖｅｌｏｐｍｅｎ...     

Inhibition of mugineic acid-ferric complex uptake in barley by copper, zinc and cobalt

The interfering effects of copper, zinc, and cobalt on the uptake of mugineic acid-ferric complex were studied in barley ( Hordeum vulgare , cv. Minorimugi) grown in nutrient solution. Short-term uptake experiments of 3 h were performed utilizing both ionic and mugineic acid-complex forms of each metal at two different concentrations. Copper was most effective in decreasing iron uptake when added in an ionic form at either concentration. The inhibition order at higher concentrations followed Cu(II) > Zn(II) ≥ Co(II), Co(III), which is consistent with the stability constants of these metal complexes with mugineic acid. The displacement of iron from its mugineic acid complex by these metals is suggested as a probable explanation for the decreased iron uptake. The inhibitory effect of metal complexes with mugineic acid on iron uptake was only found in cases with higher concentrations of Cu(II) and Zn(II) complexes. Deformation of the specific iron transport system in the plasma membrane due to their adsorption may be responsible for this effect.     

波形蛋白、核纤层蛋白与排核关系的研究

以网织红细胞与K_(582)细胞融合形成的胞质体杂种细胞K-RRneo为研究对象,对Vimentin、Lamin蛋白与K-RRneo细胞分化排核的关系进行了研究。结果表明:随着K-RRneo细胞的分化,Vimentin mRNA、Lamin蛋白表达明显降低,与我们整装电镜观察及Western印迹分析所得到的结论相一致,证实了薛社普提出的Vimentin、Lamin蛋白在红系细胞分化排核中所起的作用,为最终阐明红系细胞分化排核机制提供了新线索。     

中国稻蝗属细胞分类学研究(英文)

本文对分布于中国境内11省区,27个采集地点的八种稻蝗进行了染色体C带核型比较研究。结果表明:中华稻蝗Oxya chinensis,上海稻蝗O.shanghaiensis,无齿稻蝗O.adentata C带分布型式相似,但染色体分组型式、交叉定位数据以及异染色质含量具有差异;山稻蝗O.agauisa具有本身独特的带纹结构,与本属其它种类迥异;双带稻蝗O.bicingula染色体带型结构相似于山稻蝗及中华稻蝗类群,表明三者在进化历程中有一定联系。小稻蝗O.hyla intricata中一个亲缘种团(Sibling species group),体现在种内的形态差异及染色体带型结构的不同。显示该种近期内分化速率较高。据此,本文讨论了稻蝗属内八个种相互间的亲缘关系和分类地位,本文认为稻蝗属内务物种进化速率是不均衡的,这种状态应归因于各物种的遗传背景和环境因素的影响。     

Bioenergetics of sulfur reduction in the hyperthermophilic archaeon Pyrococcus furiosus.

The bioenergetic role of the reduction of elemental sulfur (S0) in the hyperthermophilic archaeon (formerly archaebacterium) Pyrococcus furiosus was investigated with chemostat cultures with maltose as the limiting carbon source. The maximal yield coefficient was 99.8 g (dry weight) of cells (cdw) per mol of maltose in the presence of S0 but only 51.3 g (cdw) per mol of maltose if S0 was omitted. However, the corresponding maintenance coefficients were not found to be significantly different. The primary fermentation products detected were H2, CO2, and acetate, together with H2S, when S0 was also added to the growth medium. If H2S was summed with H2 to represent total reducing equivalents released during fermentation, the presence of S0 had no significant effect on the pattern of fermentation products. In addition, the presence of S0 did not significantly affect the specific activities in cell extracts of hydrogenase, sulfur reductase, alpha-glucosidase, or protease. These results suggest either that S0 reduction is an energy-conserving reaction, i.e., S0 respiration, or that S0 has a stimulatory effect on or helps overcome a process that is yield limiting. A modification of the Entner-Doudoroff glycolytic pathway has been proposed as the primary route of glucose catabolism in P. furiosus (S. Mukund and M. W. W. Adams, J. Biol. Chem. 266:14208-14216, 1991). Operation of this pathway should yield 4 mol of ATP per mol of maltose oxidized, from which one can calculate a value of 12.9 g (cdw) per mol of ATP for non-S0 growth. Comparison of this value to the yield data for growth in the presence of S0 reduction is equivalent to an ATP yield of 0.5 mol of ATP per mol of S0 reduced. Possible mechanism to account for this apparent energy conservation are discussed.     

Pore formation by the sea anemone cytolysin equinatoxin II in red blood cells and model lipid membranes

Summary The interaction ofActinia equina equinatoxin II (EqT-II) with human red blood cells (HRBC) and with model lipid membranes was studied. It was found that HRBC hemolysis by EqT-II is the result of a colloid-osmotic shock caused by the opening of toxin-induced ionic pores. In fact, hemolysis can be prevented by osmotic protectants of adequate size. The functional radius of the lesion was estimated to be about 1.1 nm. EqT-II increased also the permeability of calcein-loaded lipid vesicles comprised of different phospholipids. The rate of permeabilization rised when sphingomyelin was introduced into the vesicles, but it was also a function of the pH of the medium, optimum activity being between pH 8 and 9; at pH 10 the toxin became markedly less potent. From the dose-dependence of the permeabilization it was inferred that EqT-II increases membrane permeability by forming oligomeric channels comprising several copies of the cytolysin monomer. The existence of such oligomers was directly demonstrated by chemical cross-linking. Addition of EqT-II to one side of a planar lipid membrane (PLM) increases the conductivity of the film in discrete steps of defined amplitude indicating the formation of cation-selective channels. The conductance of the channel is consistent with the estimated size of the lesion formed in HRBC. High pH and sphingomyelin promoted the interaction even in this system. Chemical modification of lysine residues or carboxyl groups of this protein changed the conductance, the ion selectivity and the current-voltage characteristic of the pore, suggesting that both these groups were present in its lumen.     

Crystal structures of two cyclic pseudopentapeptides containing ψ[CH2S] and ψ[CH2SO] backbone surrogates

The solid state conformations of cyclo[Gly–Proψ[CH₂S]Gly–D –Phe–Pro] and cyclo[Gly–Proψ[CH₂–(S)–SO]Gly–D –Phe–Pro] have been characterized by X-ray diffraction analysis. Crystals of the sulfide trihydrate are orthorhombic, P2₁2₁2₁, with a = 10.156(3) Å, b = 11.704(3) Å, c = 21.913(4) Å, and Z = 4. Crystals of the sulfoxide are monoclinic, P2₁, with a = 10.662(1) Å, b = 8.552(3) Å, c = 12.947(2) Å, β = 94.28(2), and Z = 2. Unlike their all-amide parent, which adopts an all-trans backbone conformation and a type II β-turn encompassing Gly-Pro-Gly-D -Phe, both of these peptides contain a cis Gly¹-Pro² bond and form a novel turn structure, i.e., a type II′ β-turn consisting of Gly–D –Phe–Pro–Gly. The turn structure in each of these peptides is stabilized by an intramolecular H bond between the carbonyl oxygen of Gly¹ and the amide proton of D -Phe⁴. In the cyclic sulfoxide, the sulfinyl group is not involved in H bonding despite its strong potential as a hydrogen-bond acceptor. The crystal structure made it possible to establish the absolute configuration of the sulfinyl group in this peptide. The two crystal structures also helped identify a type II′ β-turn in the DMSO-d₆ solution conformers of these peptides. © 1993 John Wiley & Sons, Inc.     

中国熊猴的分类整理

本文通过查看国内收藏的标本对M.assamensis进行了分类整理,认为M.a.coolidgei的亚种地位应予恢复,滇西地区熊猴可能代表一个新类群。通过t检验,滇南和越南等地与滇西北和西藏东南部等地熊猴头骨的某些特征表现出显著或极显著差异。作为区分coolidgei与assamensis的指标:coolidgei体型较小,肩背毛较短,35—75mm,背毛环纹略显或不明显,0—2环,体色更为灰暗;assamensis体型较大,肩背毛较长,85—110mm,背毛环纹明显,3—4环。