制备1,5-二磷酸核酮糖的简易方法

核酮糖1,5—二磷酸羧化酶—加氧酶(RuBPCase—Oase)是植物叶绿体中最丰富的蛋白质,它有两种催化功能:在CO_2分压高时,使1,5—二磷酸核酮糖(RuBP)羧化,产生2分子的3—磷酸甘油酸(PGA);而在O_2分压高时,使RuBP加氧,产生1分子PGA和1分子2—磷酸乙醇酸(光呼吸的主要底物),反应如下:     

Rubisco的分子生物学

核酮糖1.5一二磷酸羧化酶一氧合酶(Ribulosel,5-bisphosphate carboxylase-oxygenase,E.C.1.1.1.39,缩写为Rubisco)催化核酮糖二磷酸(RuBP)的羧化反应和氧合反应(oxygenation):     

羧基阿拉伯糖醇—1,5—二磷酸的制备

光合CO_2的固定受二磷酸核酮糖羧化酶加氧酶(Rubis CO)活性的调节,而RubisCO的活性又决定于该酶活化形式酶~(-A)CO_2-Mg~(2 )-二磷酸核酮糖(E-~ACO_2-Mg~(2 )-RuBP)复合物的数量,羧基阿拉伯糖醇-1,5-二磷酸(CABP)是RuBP强有力的竞争     

与粮农相关的植物蛋白质工程

本文扼要综述近年来国际间关于1,5-二磷酸核酮糖羧化酶-加氧酶的蛋白质工程、植物甜味蛋白质工程和改良农作物食用品质的蛋白质工程所取得的研究进展,认为这些与粮农相关的植物蛋白质工程在我国生物技术的开发应用中应该得到充分重视。     

Rubisco活化机制

Ｒｕｂｉｓｃｏ活化机制廖祥儒,朱新产（西北农业大学,陕西杨陵７１２１００）关键词Ｒｕｂｉｓｃｏ,ＣＯ_２,活化酶,ＣＡＩＰ１,５－二磷酸核酮糖羧化酶／氧合酶（Ｒｕｂｉｓｃｏ）是目前仅知的５种具有双功能催化活性的酶之一。它既能催化１,５－二磷酸核酮糖（?..     

陆地棉GhrbcMT基因克隆、表达与功能初步分析

植物的rbcMT基因编码核酮糖1,5-二磷酸羧化酶/加氧酶大亚基N-甲基转移酶(ribulose1,5 bisphosphate carboxylase/oxygenase large subunitε-N-methyltransferase, rbcMT),可能催化双功能酶核酮糖1,5-二磷酸羧化酶/加氧酶大亚基14位赖氨酸的ε-氨基的甲基化过程,目前在豌豆、小麦、烟草等中被鉴定出,可能参与调控植物生长发育,但有关GhrbcMT基因生物学功能研究尚未报道。该研究以陆地棉(Gossypium hirsutum L.)为材料,提取叶片总RNA,反转录合成cDNA,利用PCR技术克隆棉花核酮糖1,5-二磷酸加氧酶/羧化酶大亚基甲基转移酶基因(GhrbcMT)全长cDNA,对该基因进行生物信息学分析,采用荧光定量PCR(qRT-PCR)对GhrbcMT基因进行组织特异性表达分析,并用病毒诱导的基因沉默(virus-induced gene silencing, VIGS)技术降低GhrbcMT在植株中的表达水平,同时用乙醇浸泡法提取野生型与GhrbcMT干涉株系的叶片叶绿素进行含量分析。结果显示, GhrbcMT蛋白质序列存在多个潜在磷酸化与糖基化位点, Loop结构占56.94%,构象灵活。GhrbcMT基因在棉花叶片中特异性表达, GhrbcMT干涉株系的GhrbcMT表达水平显著降低,棉花出现明显的生长缓慢、节间距缩短、植株矮小、花药败育等表型, GhrbcMT基因表达水平的降低对棉花植株的营养生长和育性具有显著影响。该研究通过对1,5-二磷酸核酮糖加氧酶/羧化酶大亚基甲基转移酶功能初步探究,为进一步探究植株生长发育和育性调控机理提供参考。     

核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)

文章就核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)的分布、结构、性质、分类与功能的研究进展作了介绍。     

适于蛋白双向电泳的水稻叶片样品提取方法初探

在水稻基因组测序完成后,利用蛋白质组学技术揭示水稻基因功能的研究,已成为水稻分子生物学研究的热点之一。水稻叶片作为DNA研究的便利材料被经常使用,但对蛋白质研究来说,占叶片全蛋白50%～60%的核酮糖二磷酸羧化酶（RuBP羧化酶）对低丰度蛋白常常造成掩盖。以水稻叶片为材料,用不同浓度的聚乙二醇（PEG）去除叶片中RuBP羧化酶。通过SDS-PAGE垂直电泳比较发现,浓度为17%的PEG对去除RuBP羧化酶效果最好,所获得的蛋白质样品可以得到质量较高的双向电泳图谱。     

RubisCO的研究进展

1,5-二磷酸核酮糖羧化酶/加氧酶(RubisCO)是调节光合和光呼吸,决定净光合作用的一个关键酶;也是植物可溶性蛋白质中含量最高的蛋白质.该酶广泛存在于植物及一些微生物体内.综述了近年来有关RubisCO的一些研究进展. 包括RubisCO的基本性质、结构与功能、酶基因工程、酶活性调节及其活化酶等.     

蚕豆核酮糖1，5-磷酸羧化酶／加氧酶大亚基基因的分子克隆

核酮糖l,5－二磷酸羧化酶／加氧酶由大亚基(Ls)和小亚基组成。Ls由叶绿体DNA编码。蚕豆Ls的基因已被克隆到pBR322。应用几种限制性内切酶酶解以及Southern印迹法构建了该重组质粒的物理图谱。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.