小球藻RubisCO的纯化及其在异养向自养转变过程中的含量变化

经硫酸铵分部沉淀、ＳｅｐｈａｃｒｙｌＳ－３００和ＤＥＡＥ－纤维素柱层析纯化了小球藻ＲｕｂｉｓＣＯ,得率为１５％,比活力达１．２３２μｍｏｌＣＯ２ｍｓ－１ｍｉｎ－１,分子量是５００ｋＤ,它和菠菜叶片ＲｕｂｉｓＣＯ在分子量、亚基组成和免疫特性等方面相似,反映ＲｕｂｉｓＣＯ在高等和低等植物中有较高的同源性。自养小球藻ＲｕｂｉｓＣＯ占细胞可溶性蛋白质的２４％。而异养转变后的小球藻细胞内不含ＲｕｂｉｓＣＯ。异养小球藻向自养生长转变过程中,２０ｈ后细胞内叶绿素含量逐渐增加,２４ｈ时细胞内出现ＲｕｂｉｓＣＯ,２４ｈ后大量增加,至４１ｈ时含量达最高峰;标志着小球藻细胞光合作用能力的恢复和加强。     

ＴＮＦ—α基因在鱼腥藻７１２０中的表达及其产物的亲和层纯化

用转入ＴＮＦ－α基因并稳定有达了４年多的丝状体蓝藻－鱼腥藻７１２０（Anabaena sp.PCC7120),研究比较了在培养液中氨源（NaNO3)和碳源（NaAc)对转基因灌生长和ＴＮＦ－α基因的不同影响,氨源能稳定外源蛋白的表达,而碳源则影响细胞壁的合成。通过比较不同的破碎细胞的方法,发现超声破碎得到的可溶性总蛋白含量和ＴＮＦ－α含量均要比冻融法高出１倍左右,经过细胸破碎、硫酸铵分级沉淀、常压离子交换液相色析后,除去杂蛋白及大量容易堵柱的糖类等物质,最后通过亲和柱层析,分离出了纯的目标蛋白－重组肿瘤坏死因子（ＴＮＦ－α）。经凝胶电泳鉴定为单一的谱带,分子量为１７kD。     

佛波酯对NIH3T3细胞整合蛋白α_5亚基表达的影响

１００ｎｍｏｌ／Ｌ佛波酯（１２－Ｏ－ｔｅｔｒａｄｅｃａｎｏｙｌｐｈｏｂｏｌ１３－ａｃｅｔａｔｅ,ＴＰＡ）作用于ＮＩＨ３Ｔ３细胞２４ｈ,流式细胞仪检测到细胞表面整合蛋白α５亚基含量增加５２．３％．Ｎｏｒｔｈｅｒｎ杂交方法测定结果亦表明整合蛋白α５亚基ｍＲＮＡ量增加,于２ｈ时达到高峰,为对照的４．１４倍．蛋白激酶Ｃ（ｐｒｏｔｅｉｎｋｉｎａｓｅＣ,ＰＫＣ）的活性增加趋势与之基本一致．运用ＰＫＣ的抑制剂鞘氨醇（ｓｐｈｉｎｇｏ－ｓｉｎｅ）和酷氨酸激酶（ｔｙｒｏｓｉｎｅｋｉｎａｓｅ,ＴＫ）抑制剂４,５,７－三羟基异黄酮（ｇｅｎｅｓｔｅｉｎ）进一步研究,发现两者均可抑制佛波酯对整合蛋白α５亚基表达的上调作用．提示佛波酯对ＮＩＨ３Ｔ３细胞整合蛋白α５亚基表达的调控与ＰＫＣ和ＴＫ均有关．     

论文摘要

豌豆种子中含有豆球蛋白和豌豆球蛋白这两类主要的贮存蛋白,后者是可在亚基结构上所免疫特异蛋白加以区别的混合物。两类蛋白在亚基结构上存在微小的差异,并且在结构和数量上受不同的基因型支配。对豆球蛋白的遗传结构和生物合成的研究表明;有一族为许多前体分子编码的基因,又由这些前体分子产生了分子量约为40×10~3(α球     

甘薯叶片蔗糖酶的分离纯化及其部分性质

纯化酶经聚丙烯酰胺凝胶电泳显示单一蛋白带,ＳＤＳ－ＰＡＧＥ显示一条蛋白带,其亚基分子量为３９．８ｋＤ。用Ｓｅｐｈａｃｒｙｌ Ｓ－２００凝胶过滤测得全酶的分子量为７９．４ｋＤ,该酶由两个相同亚基组成。其表观Ｋｍ为１２ｍｍｏｌ／Ｌ,Ｖｍａｘ为９９．５ｍｇ还原糖ｍｇ＾－１ｐｒｏｔｅｉｎ ｈ＾－１。     

豌豆中可与Gol EL抗体发生免疫学反应的热激诱导蛋白

通过Ｗｅｓｔｅｒｎ印渍方法,发现在豌豆叶存在一种高分子量的蛋白可与ＧｒｏＥＬ抗体发生免疫学反应,它含有两种亚基,分子量分别为６０．４ｋＤ（α）和６５．５ｋＤ（β）,具有弱的ＡＴＰａｓｅ活性。热激处理后此蛋白的表达升高３￣４倍,但外源ＡＢＡ处理并不增加它的表达。用＾３５Ｓ标记蛋白和氯霉素抑制实验表明,此蛋白可能是在８０Ｓ核糖体上合成的胞质蛋白。     

影响豌豆Rubisco组装的因子及其作用机制

将新鲜制备的不含Rubisco的豌豆叶片低分子量（LMW）蛋白组分在离体条件下室温保温48h后,经ND－PAGE分析发现,ATP和Mg^2 是组装的必需条件。随着Mg^2 浓度的增加,组装成的Rubisco量逐渐增加,直至其浓度到2．5mmol/L后达到平衡。K^ 对组装有抑制作用,抑制程度随着K^ 浓度增加逐渐增强,当K^ 浓度为5mmol/L时组装被抑制56％,当K^ 浓度达到40mmol/L时,组装被抑制高达90％以上;但同样浓度的Na^ 则没有抑制作用。另外,以羟自由基对豌豆LMW蛋白组分中的大亚基进行降解处理,对大亚基专一性降解肽谱与对全酶中和相同,也能产生37kD的降解肽段,而且,预先经ATP和Mg^2 处理的样品,LMW组分中37kD的大亚基降解条带会消失,而在20－30kD位置附近产生新的降解条带;而K^ 预处理同样能够产生20－30kD大亚基的降解条带,但其37kD的大亚基降解条带没有消失,这说明K^ 对组装的抑制作用可能是通过与组装中间体结构后产生不利于组装的构象变化实现的。     

限制性核酸内切酶Bsp 63Ⅰ的纯化及性质研究

用Ｂａｃｉｌｌｕｓｓｐｈａｅｒｉｃｕｓ６３菌为材料,经ＤＮＡ－Ｓｅｐｈａｒｏｓｅ和ＣｉｂａｃｒｏｎＢｌｕｅＦ３ＧＡ－Ｓｅｐｈａｒｏｓｅ两步亲和层析,将Ｂｓｐ６３Ⅰ纯化到均一程度。酶比活力达６１４００Ｕ／ｍｇ蛋白。用凝胶过滤法测得该酶分子量为１１３８００。该酶样品在ＳＤＳ－ＰＡＧＥ中呈现为一条蛋白带,并测得其亚基分子量为５６８００。用ＤＮＳ－Ｃｌ法测得该酶Ｎ－末端氨基酸为丙氨酸。上述结果表明该酶分子是由两个相同亚基组成。     

小鼠金属硫蛋白──I cDNA在蓝藻中的克隆和表达

生物工程技术在工业、农业和环境保护上的应用日益广泛,将工程微生物应用于环境污染的治理,是一条快速、安全又经济的途径。本文报道了获得一种清除重金属污染工程藻的研究。将小鼠金属硫蛋白－Ｉ（ｍｏｕｓｅｍｅｔａｌｌｏｔｈｉｏｎｅｉｎ－Ｉ,ｍＭＴ－Ｉ）ｃＤＮＡ基因片段插入到质粒ｐＲＬ４３９上的强启动子ＰｐｓｂＡ之后,并与穿梭载体ｐＤＣ－８相连构建成功大肠杆菌──蓝藻穿梭表达载体ｐＤＣ－ＭＴ,然后通过三亲结合转移法将ｐＤＣ－ＭＴ转入固氮丝状体蓝藻鱼腥藻（Ａｎａｂａｅｎａ）７１２０中,经新霉素筛选获遗传稳定的转外源ＤＮＡ藻株;纯化单藻落扩大培养后,提取蓝藻质粒,斑点杂交确定ｍＭＴ－ＩｃＤＮＡ的转人;在培养基中加入重金属Ｃｄ,培养后收集藻细胞,用ＷｅｓｔｅｒｎＢｌｏｔｔｉｎｇ,极谱法和原子吸收等多种方法确定金属硫蛋白的表达,并计算表达量约为４０μｇＭＴ／ｇ藻鲜重。     

豌豆中可与Gro EL抗体发生免疫学反应的热激诱导蛋白

通过Ｗｅｓｔｅｒｎ印渍方法,发现在豌豆（ＰｉｓｕｍｓａｔｉｖｕｍＬ．）叶存在一种高分子量的蛋白可与ＧｒｏＥＬ抗体发生免疫学反应,它含有两种亚基,分子量分别为６０．４ｋＤ（α）和６５．５ｋＤ（β）,具有弱的ＡＴＰａｓｅ活性。热激处理后此蛋白的表达升高３～４倍,但外源ＡＢＡ处理并不增加它的表达。用３５Ｓ标记蛋白和氯霉素抑制实验表明,此蛋白可能是在８０Ｓ核糖体上合成的胞质蛋白。     

Coral-reef sounds enable nocturnal navigation by some reef-fish larvae in some places and at some times

At Lizard Island, Great Barrier Reef, catches of fish larvae by light traps that broadcast nocturnal reef sounds (noisy traps) were compared with catches by quiet traps over two 2·5 week new-moon periods in November (XI) 2000 and January (I) 2001. Three areas were sampled: near-reef (NR, 500 m from the shore) in I, middle (M, 650 m) in I and XI and offshore (O, >1000 m) in XI. The most abundant taxa captured were Apogonidae, Blenniidae, Chaetodontidae, Lethrinidae, Mullidae and Pomacentridae. Significant differences in catch were found between areas, and a position effect was found at the O and M areas. At the NR and M areas, no taxa had significantly greater catches in quiet traps, but larvae of five taxa had significantly greater catches in noisy traps. These were (areas and times of greater catches): Apogonidae (NR; M XI), Mullidae (M I & XI), Pomacentridae (NR; M I & XI), Serranidae (M I) and Sphyraenidae (NR). At the offshore area, five taxa (Apogonidae, Blenniidae, Chaetodontidae, Mullidae and Pomacentridae) had significantly greater catches in quiet traps and only Lethrinidae had significantly greater catches in noisy traps. Thus some taxa (particularly apogonids and pomacentrids which had catches up to 155% greater in noisy traps, but also lethrinids and mullids, and perhaps others), were attracted to reef sounds at night, but this apparently varied with location and time. The sound-enhanced catches imply a radius of attraction of the sound 1·02–1·6 times that of the light. More than 65 m from the speaker,the broadcast sound levels at frequencies typical of fish hearing were equivalent to background levels, providing a maximum radius of sound attraction in this experiment.     

Antifungal activity of some plant extracts on some pathogenic fungi

The inhibitory activity of five plant extracts viz. Artemisia absinthium L., Rumex obtusifolius L., Taraxacum officinale Weber ex Wiggers, Plantago lanceolata L. and Malva sylvestris L. were evaluated against the mycelial growth of three fungi Alternaria alternata (Fr.) Keissler, Penicillium expansum Link ex Thom. and Mucor piriformis Fisher that cause rot diseases in fruits and vegetables resulting in low yield and quality of fruits and vegetables. Results revealed that all the concentrations of plant extracts brought about significant inhibition in the mycelial growth of these pathogenic fungi. However, the highest concentration caused maximum inhibition in the mycelial growth followed by lower concentrations of plant extracts. The extract of A. absinthium leaves at highest concentration (S) proved highly effective in inhibiting the mycelial growth of all these pathogenic fungi followed by other plant extracts. These plants thus may have potential as the new natural fungicide for management of fungal rot diseases.     

People's concerns about biotechnology: some problems and some solutions

Pharmaceuticals and vaccines made by genetic engineering are well accepted all over the world. In contrast, there are many people, particularly in Europe, who are worried that food, made by the same new technology, may harm their health or cause damage to the environment. This is despite the growing evidence that genetically modified crops have the potential to improve world food security and the fact that there have, as yet, been no adverse results of their use in the food chain. Because of these worries and the mechanisms of politics, agricultural biotechnology has become the target of concerns about food safety (BSE, Foot & Mouth Disease), along with globalisation and the power of multinational companies. These concerns will, hopefully, be overcome by a more open and well-informed dialogue between scientists, opinion leaders, educators and the public. If judiciously applied, genetically modified crops will help increase sustainability and the fight against hunger in the world.     

Introductory review some new thoughts about some old malaria models

Simple models for the dynamics of endemic malaria are reviewed. A reanalysis of Ross's models explains Lotka's interpretation of them, and finds a historical context for the vectorial-capacity construction of an inoculation rate. Important epidemiological parameters are scrutinized. Inference problems are discussed concerning estimating mosquito density, recognizing the maternal-antibody effect, choosing among models for superinfection, and accounting for diagnostic error.     

Cytoembryology of some Malaysian dipterocarps, with some evidence of apomixis

KAUR, A., JONG, K., SANDS, V. E. & SOEPADMO, E., 1986. Cytoembryology of some Malaysian dipterocarps, with some evidence of apomixis. Embryological and cytological studies on some members of the Dipterocarpaceae were undertaken. Of the dipterocarps investigated 83% were diploids. Two new polyploids were observed, namely Shorea resinosa (2 n = 3x = 21) and Hopea subalata (2 n = 3x = 21). Multiple seedlings were observed in H. subalata, Shorea agami, S. argentifolia, S. ovalis, S. pauciflora and S. resinosa. For the first time embryological studies have conclusively demonstrated reproduction by agamospermy in 5. ovalis and S. agami. Considerable evidence leads to the inference that H. subalata, S. resinosa and 5. macroptera are also agamosperms. Each of these produces multiple seedlings. Of these apomictic species three are polyploids, namely S. ovalis (2 n = 4x = 28), H. subalata (2 n = 3x = 21) and S. resinosa (2 n = 3x = 21), whereas S. agami (2 n = 14) and S. macroptera (2 n = 14) are diploids.     

A note on some old and some possible new redox indicators

Summary Starting with the frequently used dye 2,6-dichloroindophenol some of the chemical properties of the quinonimide class of dyes are described. Consideration of the effects of completing a hetero-six-membered ring, as in the azine, thiazine and oxazine classes, on the properties of the compounds is suggested as a lead towards the development of some redox indicators perhaps more desirable than the indophenols. This approach developed from a study of the Liebermann nitroso-reaction for phenols. Some properties of the redox indicators which resulted from that work are described in relation to energy transduction in the chloroplast.