Acid-Catalyzed Stereoselective Cyclization of Germacrene D

A monohalomethane-producing enzyme, S-adenosyl-L-methionine-dependent halide ion methyltransferase (EC 2.1.1.-) was purified from the marine microalga Pavlova pinguis by two anion exchange, hydroxyapatite and gel filtration chromatographies. The methyltransferase was a monomeric molecule having a molecular weight of 29,000. The enzyme had an isoelectric point at 5.3, and was optimally active at pH 8.0. The K_m for iodide and SAM were 12 mM and 12 μM, respectively, which were measured using a partially purified enzyme. Various metal ions had no significant effect on methyl iodide production, suggesting that the enzyme does not require metal ions. The enzyme reaction strictly depended on SAM as a methyl donor, and the enzyme catalyzed methylation of the I^-,Br^-, and Cl^- to corresponding monohalomethanes and of bisulfide to methyl mercaptan.     

红褐斑腿蝗卵黄蛋白的分离纯化及性质分析

用蒸馏水沉淀法、凝胶过滤、蛋白质电泳等方法提取纯化了红褐斑腿蝗Catantops pinguis (Stål)的卵黄蛋白,并对其性质进行了分析。电泳结合不同的染色方法证明红褐斑腿蝗的卵黄蛋白为一种糖脂复合蛋白,其分子量约为548 kD,由7个亚基组成,亚基分子量分别为147.3,100.2,95.9,59.6,53.6,49.0和42.2 kD。卵黄蛋白经高效液相色谱分析检测到17种氨基酸和NH₃峰,其中谷氨酸（Glu）百分含量最高,达13.46%,天冬氨酸（Asp）、亮氨酸（Leu）、半胱氨酸（Cys）、精氨酸（Arg）含量比较高,脯氨酸（Pro）、组氨酸（His）、赖氨酸（Lys）含量较低。     

The neo-XY system of Catantops humilis (Acrididae: Catantopinae) in Malaysia

Catantops humilis lives on the leguminous covercrop in young rubber and oil palm plantations on the coastal plains of Peninsular Malaysia. The grasshopper has high dispersal capability, and migrates when the trees mature, so distribution of populations changes regularly. Southern populations have normal 2 n =23, XO/24, XX complements. In Selangor State two morphologically indistinguishable chromosomal forms comprising XO and neo-XY males with basic homozygote and fusion heterozygote females, exist sympatrically in the same microhabitat in eight localities. In one population where occasional sharp reduction in numbers and migration occur, the centric rearrangement has attained a 40–50% frequency. A further mixed population was found 300 km north. Consideration is given to the possibilities that these mixed populations are part of a broad region of hybridization between two chromosomal races, or that they represent a widespread polymorphism.     

Studies on the fine structure of Glaucocystis nostochinearum Itzigs. II. Membrane morphology and taxonomy

The fine structure of the alga Glaucocystis nostochinearum Itzigs. has been studied by thinsectioning and freeze-etching. Many of the features already established by sectioning have been verified but different conclusions are drawn, particularly with regard to the photosynthetic organs. The action of glycerol solutions on the morphology of the plasmalemma as revealed by freeze-etching is shown to be of general importance for the freeze-etching of plant cells and of particular importance in elucidating the true form of the plasmalemma in Glaucocystis. The literature regarding the taxonomic position of Glaucocystis has been reviewed, and, along with a completely new demonstration of plasmalemma structure, an attempt has been made to reclassify this organism.     

Reproductive bionomics of two sublittoral amphipods in a Bay of Fundy estuary

The reproductive bionomics of two Canadian sublittoral amphipods, Casco bigelowi and Leptocheirus pinguis, are compared in a Bay of Fundy estuary. Casco is semelparous and Leptocheirus iteroparous, although both have a biannual life history. The relatively high reproductive potential of each species, Casco with a reproductive potential of 12.5 and Leptocheirus with 25.5 young per year, is dictated by a combination of wave-caused sediment washout and prédation within the estuary.     

红褐斑腿蝗的耐寒能力及其季节性变化

用测定过冷却点的方法研究了红褐斑腿蝗(Catantops pinguis (Stal))在不同季节的抗寒能力,并就虫体含水量、粗脂肪、总蛋白和总糖等成分在不同季节的变化及其对过冷却点的影响进行了探讨.结果表明,红褐斑腿蝗的过冷却点存在显著的季节性差异,依次为秋季种群((-23.1 ± 0.2 )℃)＜ 越冬后种群((-19.3 ± 0.1) ℃)＜ 夏季种群((-4.0 ± 0.1) ℃).含水率在生长期极显著高于越冬期,越冬初期和越冬后期变化不大,说明红褐斑腿蝗在越冬准备期已排出了体内多余的游离水.越冬后蝗虫体内总糖含量和脂肪含量均显著低于越冬初期,说明蝗虫在越冬时主要靠消耗体内的碳水化合物和脂肪物质来维持体温,体内的营养物质消耗极大,导致越冬后过冷却点显著上升.含水率和含脂率在两性间差异不显著,雌性蝗虫的总蛋白含量在夏季种群略高于雄性,越冬期显著低于雄性,可能与雌蝗孕卵过程中动用了大量营养物质有关.     

ISOLATION OF THREE NOVEL LONG‐CHAIN POLYUNSATURATED FATTY ACID Δ9‐ELONGASES AND THE TRANSGENIC ASSEMBLY OF THE ENTIRE PAVLOVA SALINA DOCOSAHEXAENOIC ACID PATHWAY IN NICOTIANA BENTHAMIANA1

The transgenic aerobic synthesis of long‐chain polyunsaturated fatty acids (LC‐PUFA) will in most land plants commence with either a Δ6‐desaturation or a Δ9‐elongation. Numerous Δ6‐desaturases have been characterized, but only one Δ9‐elongase has been reported in peer‐reviewed literature. In the present study, we describe the isolation of three additional Δ9‐elongases from the class Haptophyceae and demonstrate that the Δ9‐elongase group contains highly conserved regions, which differentiate them from other ELO‐type elongases. One such important difference is the presence of an LQxFHH motif instead of the usual LHxYHH motif, a feature that should simplify further gene discovery efforts in this group of enzymes. Moreover, the identification of the Pavlova salina (N. Carter) J. C. Green Δ9‐elongase completes the isolation of the entire P. salina docosahexaenoic acid (DHA) pathway, and we describe the assembly of this pathway in Nicotiana benthamiana. Finally, we comment on possible explanations for the widespread presence of the Δ6‐desaturated fatty acid stearidonic acid (SDA, 18:4^Δ6,9,12,15) in the plastidial lipids of organisms using the Δ9‐elongase pathway.     

红褐斑腿蝗血细胞的形态与分类

利用光学显微镜和显微数码拍照系统,对红褐斑腿蝗Catantops pinguis(Stal)血细胞的形态进行观察和分类。结果在红褐斑腿蝗血淋巴中观察到5种血细胞,分别是原血胞、浆血胞、粒血胞、珠血胞和囊血胞。原血胞为小型圆形细胞,边缘圆滑、清晰,核质比例很大。粒血胞多为中型,形状不规则,边缘凹突不平,内含较大的异质性溶酶体颗粒。浆血胞多为中型,刚离体时形状较规则,常呈圆形、卵圆形。浆血胞内缺乏大的颗粒,细胞核大而圆形,细胞质内具许多小型颗粒状物质。浆血胞离体后形状变化较多,常发展出伪足,呈丝状、短芒状、钩状或片状伪足。珠血胞多为大、中型,外形大体呈圆形,但边缘由于大小不等的珠形内含物突出,呈花瓣状。囊血胞多为中型,圆形或椭圆形,细胞质内具有大小不一的带有折光性的颗粒或块状物,细胞边缘比较光滑。     

Leakage of 5′-Guanosine Monophosphate from Candida lipolytica (IFO, 0746) and Its Mutants

5′-Guanosine monophosphate (5′-GMP) was found to leak from Candida lipolytica (IFO, 0746) and its mutant Y and Sm.

Mutant Sm obtained from the parent strain by treatment with N-methyl-N′-nitro-N-nitrosoguanidine (NTG) and ultraviolet irradiation was found to leak 5′-GMP at 5 times the amount of the parent strain. The properties of mutant Y and Sm were compared with the parent strain, and differences were present in growth, amount of 5′-GMP leakage and ribonuclease activity.     

红褐斑腿蝗的食物消耗与利用及其对温度的依赖性

昆虫是变温动物 ,外界温度的波动会影响昆虫的体温 ,这也必然会影响昆虫的新陈代谢 ,从而引起一系列生理生化反应。红褐斑腿蝗 [Ｃａｔａｎｔｏｐｓｐｉｎ ｇｕｉｓ(Ｓｔａｌ) ]是浙江农田常见的蝗类害虫 ,分布广 ,数量多 ,常为害玉米 (Ｚｅａｍａｙｓ)、豆类 (Ｇｌｙｃｉｎｅｍａｘ)及茶树 (Ｃａｍｌｌｉａｓｉｎｅｎｓｉｓ)。据作者观察 ,该种蝗虫常以成虫越冬 ,而浙江省冬季最冷的 1月份平均气温为 2 5～ 7 5℃ ,极端低温多年平均在 - 8℃以下。文献研究表明 ,红褐斑腿蝗的过冷却点可达 - 2 0℃以下 (有关结果拟另文发表 ) ,显示其具…