取食雄蜂蛹粉对龟纹瓢虫和异色瓢虫卵黄发生的影响

本文比较了龟纹瓢虫Proylea japonica和异色瓢虫Harmonia axyridis取食蚜虫和取食雄蜂蛹粉时的卵黄发生情况.当取食雄蜂蛹粉时,体内卵黄蛋白出现迟,积累速度慢,产卵前期长.但用保幼激素类似物ZR512点滴处理后则能达到与食蚜对照相当的水平.ZR512对取食雄蜂蛹粉瓢虫的作用显著大于取食岈虫者.进一步的研究表明,ZR512能促进这两种瓢虫取食雄蜂蛹粉,但对成虫的体重没有明显的影响.因此推论,雄蜂蛹粉基本能够满足这两种瓢虫生殖的营养需要,但对其内分泌有一定的影响,使瓢虫处于类似生殖滞育的状态.本文根据不同食物条件对卵黄蛋白发生的影响不同,建议用卵黄蛋白的量作为生理指标,以快速初步筛选和评估人工饲料.     

两种品系油菜植株成分与蚜虫种群消长及成蚜翅型的关系

本文研究两种品系油菜植株成分与桃蚜(Myzus persicae(Sulzer))、萝卜蚜(Lipaphis erysimi(Kaltenbach))的种群消长及成蚜翅型的关系.经分析得出如下结果:1.桃蚜种群消长与苏氨酸、赖氨酸、组氨酸、丙氨酸、硬脂酸等含量有关;桃蚜成蚜无翅率与精氨酸、谷氨酸、酪氨酸、异亮氨酸等含量有关.2.萝卜蚜种群消长与苏氨酸、蛋氨酸、异亮氨酸、苯丙氨酸、酪氨酸、含水量有关;萝卜蚜成蚜无翅率与含水量.亚麻酸.苏氨酸、油酸,天门冬氨酸、丝氯酸、亚油酸等含量有关.     

Thromboxane receptor antagonism combined with thromboxane synthase inhibition. 6. 4-substituted 3-pyridinylalkanoic acids.

(3-Pyridinyl)alkanoic acids substituted at the 4-position with an (arylsulfonamido)alkyl group were synthesized and found to behave as platelet thromboxane receptor antagonists (TxRAs) and thromboxane synthase inhibitors (TxSIs). The compounds behaved as agonists at the vascular receptor for thromboxane A₂.     

商陆根中抗真菌蛋白的分离和特性研究

从美洲商陆(Phytolacca americana L.)夏天采集的2—4年生宿根中分离了二种抗真菌蛋白,称为PAFP-R_1和PAFP-R_2。分离程序包括用盐溶液提取,经CM-Sephadex离子交换层析、凝胶过滤层析和羟基磷灰石柱层析纯化。在PGA培养基上,0.1mg/ml蛋白明显抑制木霉菌丝的生长;但对细菌的增殖,即使1mg/ml也无抑制作用。用SDS-PAGE测得二者的相对分子量各为13kD和15kD,单多肽链,等电点约为5.8。用酚-硫酸法未测出含糖。二种蛋白均高含半胱氨酸(19mol/mol)。用Edman降解法测得二者的N末端均为Ala。秋天采集的根中,这二种蛋白含量均很低,但富含由二条PAFP-R_1肽链以双硫键联结的二聚体,它无抗真菌活性。冬天宿根中抗真菌蛋白主要成分是Mr为17kD的单肽链蛋白。上述蛋白对于人红血球均无凝集活性,因此不是PWM的成分。以上结果说明,商陆根中有多种具抗真菌活性的蛋白,成分随季节发生变化,它们都是不含糖,高含半胱氨酸,分子量小于20kD的单肽链蛋白。     

Mechanism for the opioid-induced twitch potentiations of frog's skeletal muscle

The twitch-potentiating effects of opioids in the frog's skeletal muscle which are naloxone resistant and nonstereospecific were further studied. The rapid kinetics of the onset and of the offset (following washout) of the opioid effect indicates that the site for this action is the surface membrane of the muscle fibre. On the other hand, the lack of any twitch-potentiating effect by naloxone methylbromide, a quaternary derivative of naloxone, suggests that opioids which potentiate the twitch must enter the lipid phase of the membrane to act. Intracellular microelectrode experiments revealed no relation between the opioid effects on membrane electrical events and twitch potentiation. Blocking slow calcium channels with D-600 did not modify the opioid-induced twitch potentiation. The twitch potentiation was antagonized by increasing the extracellular calcium concentration, [Ca2+]o, to 8.64 mM. The effects of closely spaced multiple electrical pulses revealed that the opioids decreased the summated response relative to predrug controls. The results suggest that opioids facilitate the process of excitation-contraction coupling in the frog's skeletal muscle by the release of an additional amount of "trigger calcium" following a single electrical stimulus, thereby generating a potentiated twitch.     

Genotype dependent variation in mycorrhizal colonization and response to inoculation of pearl millet

Summary Genotypes of pearl millet (Pennisetum americanum L. Leeke) were examined for differences in vesicular-arbuscular mycorrhizal (VAM) colonization and response to inoculation. For thirty genotypes tested across three field locations there was a range of mycorrhizal colonization intensity between 25 and 56%. In another experiment with two male-sterile lines, restorer lines and their derived crosses, grown in pots filled with non-sterilized soil there were significant differences between genotypes for colonization by mycorrhiza. This showed hostgenotype dependence for mycorrhizal colonization.Root growth rates, mycorrhizal root length, percentage root colonization and plant growth and P uptake were studied in ten genotypes. A set of 3 genotypes with similar root lengths varied significantly with regard to mycorrhizal root length and the percentage colonization. This supports the suggestion that VAM colonization and spread is dependent on the host genotype. The growth responses differed significantly between the genotypes and they also differed in their responses to P uptake and VAM inoculation. The utility of host-genotype dependent differences in VAM symbiosis in plant breeding is discussed.Journal Article No. 453     

Production of l-Phenylalanine from Starch by Analog-Resistant Mutants of Bacillus polymyxa

p-Fluorophenylalanine-resistant mutants of starch-degrading Bacillus polymyxa ATCC 842, generated by ethyl methanesulfonate mutagenesis followed by incubation with caffeine, overproduced small amounts of l-phenylalanine (l-phe) from starch. A beta-2-thienylalanine-resistant mutant (BT-7) derived from p-fluorophenylalanine mutant (C-4000 FP-4) and resistant to both p-fluorophenylalanine and beta-2-thienylalanine produced 0.5 g of l-phe and 0.15 g of l-tyrosine per liter from 10 g of starch per liter when growing in a minimal medium. trans-Cinnamic acid (CA) was also excreted by both mutants, indicating the possibility of l-phenylalanine ammonia-lyase-induced deamination of l-phe to CA. The amount of l-phe-derived CA detected in BT-7 was less compared with mutant C-4000 FP-4. CA production was induced in the parent only when l-phe was used as a sole nitrogen source. Time of CA production in the two mutants could be delayed by addition of other nitrogen sources, an indication of possible l-phenylalanine ammonia-lyase inhibition or repression. The presence of l-phenylalanine ammonia-lyase in B. polymyxa mutant C-4000 FP-4 was confirmed by assays of cell-free extracts from cells grown in starch minimal medium containing l-phe as the sole nitrogen source. Preliminary studies of the regulation of deoxy-d-arabino-heptulosonate-7-phosphate synthase and prephenate dehydratase in the wild-type strain showed that deoxy-d-arabino-heptulosonate-7-phosphate synthase was subject to feedback inhibition by l-phe, l-tyrosine, and l-tryptophan. Inhibition by each amino acid was to a similar extent singly or in combination at a 0.5 mM level of each amino acid. Prephenate dehydratase was feedback inhibited by l-phe, but not by l-tyrosine or l-tryptophan or both. In the double analog-resistant mutant BT-7, deoxy-d-arabino-heptulosonate-7-phosphate synthase had specific activity similar to that in the wild type, and the enzyme was still subject to feedback inhibition. However, prephenate dehydratase had increased specific activity and it was also insensitive to feedback inhibition by l-phe. The overproduction of aromatic amino acids by BT-7 was thought to be due, at least in part, to deregulation of feedback inhibition of prephenate dehydratase. Chorismate mutase was not subject to feedback inhibition in the wild type and was unaffected in the mutant.     

楝科植物油及种核粉抽提物对稻瘿蚊产卵忌避作用及防治试验

稻瘿蚊Orseolia oryzae发生世代亟叠,复杂,为害严重,是我国华南地区及东南亚水稻产区的重要害虫。近几年来,我们应用楝科等杀虫植物进行了防治试验,本文主要报道楝科种子油及其抽提物引起产卵稻瘿蚊忌避反应及防治效果。     

Purification and general properties of δ-aminolaevulate dehydratase from Nicotiana tabacum L

1. delta-Aminolaevulate dehydratase (EC 4.2.1.24) was purified 80-fold from tobacco leaves and its properties were studied. 2. The enzyme had optimum pH7.4 in potassium phosphate buffer, K(m)6.25x10(-4)m at 37 degrees and pH7.4, optimum temperature 45 degrees and an activation energy of 11100 cal./mole. 3. The enzyme lost activity when prepared in the absence of cysteine, and this activity was only partly restored by the later addition of thiols. Reagents for thiol groups inactivated the enzyme. 4. Mg(2+) was essential for activity, and EDTA and Fe(2+) were inhibitory; Mn(2+) was an activator or an inhibitor depending on the concentration.     

三化螟有效积温的研究——Ⅰ.各虫态期的发育零点和其有效积温

1.三化螟卵、幼虫和蛹的发育起点和发育零点都系实测结果。卵的孵化零点为16℃,胚胎发育零点为15℃,幼虫发育零点为12℃,幼虫的化蛹零点和蛹的羽化零点都为15℃。 2.三化螟各虫态的有效积温,卵平均为81.1日度,幼虫为507.2日度,蛹为103.7日度,共计为692.0日度。卵和蛹的有效积温随着温度的上升而增加,而幼虫的则恰为相反。 3.发育零点的测定方法有实测,计算和图测三种。后面两种方法所得的结果都与实测的有一定的距离。