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.     

根分泌物及其生态效应

根分泌物是个古老而年轻的研究领域。早在18,19世纪,人们(Plenk,1795;Decandolle,1830)就观察到根分泌物对邻近植株的促生和抑制作用,1904年Hilter提出“根际”的概念,标志着人们对根分泌物及其生态效应的进一步认识。此后人们对根分泌物研究逐步展开。Lyon和Willson(1920)发现,生长于无菌水培液中的植物能释放有机物,为深入研究奠定了基础。但很长一段时间这个研究领域一     

外周损伤引起成年大鼠体感皮层的功能重组

为了了解外周神经损伤对体感皮层分域组构的影响,在成年大鼠上观察了切断坐骨神经(SC)前、即刻和切断后数周内后爪皮层代表区的改变。在盐酸氯胺酮麻醉下,用微电极记录后爪皮肤轻触刺激在对侧体感皮层工区诱发的多单位反应,得出后爪的皮层代表区图。在16例中,8例大鼠观察了切断SC的即时效应。结果表明,不但SC代表区丧失皮肤反应性,原隐神经(SA)代表区的皮肤反应性也明显下降或消失,同时神经元自发活动也明显减弱。另8例大鼠在切断后数周内做了1～3次重复测定。在最初几天,原SA代表区范围内多数记录点的皮肤反应性仍未恢复,但在原SC代表区内,一些记录点转而对SA皮肤轻触刺激起反应。在随后数周内SA代表区进行性地扩张,占领了大部分原SC代表区。这一结果说明成年大鼠外周神经损伤可导致体感皮层发生显著的重组改变。     

Kinetic measurements of fusion of phosphatidylserine-containing vesicles by electron microscopy and fluorometry

Large unilamellar vesicles (REV) containing phosphatidylserine and phosphatidylethanolamine at a ratio of 1:3 were induced to fuse by adding calcium (4 mM). The kinetics of fusion was monitored by fluorometry using terbium or dipicolinic acid-containing vesicles. The morphology and the states of vesicle aggregation and fusion were examined at approx. 2, 30, 60, 150 and 900 s after calcium addition, by rapid quenching and freeze-fracture electron microscopy. The size and the state of aggregation of vesicles are quantitated from 4000 randomly selected vesicles. The aggregation and fusion kinetics as assayed by fluorescence volume mixing is very well simulated and predicted by the mass action model. The model essentially predicts the time course of the distribution of the aggregates and the increase in size of fused particles as measured by electron microscopy, although in some cases the predicted fusion rate exceeds that by morphometric measurement. No morphological features can be defined as fusion intermediates, although bead-like and rim-like materials may be attributed to the remnants of broken diaphragms between fusion partners.     

关于法氏囊内T细胞及腔淋巴细胞的研究

本实验表明,法氏囊内存在一个T淋巴细胞弥散渗透区(DIA),在初生雏鸡中开始形成,一月半发育完善,同样在ISE(滤泡间上皮)上皮层内亦存在少量的弥散T淋巴细胞,上述淋巴细胞与腔淋巴细胞,形态结构极为相似。酯酶活性反应均显示T细胞型。 另外初生雏鸡切除胸腺,不仅影响DIA的发育而且影响滤泡的发育。     

Action of polyethylene glycol on the fusion of human erythrocyte membranes

Summary Factors affecting the polyethylene glycol (PEG)-induced membrane fusion were examined. Human erythrocyte membrane ghosts, cytoskeleton-free vesicles budded from erythrocytes, mechanically disrupted erythrocyte vesicles, and recombinant vesicles from glycophorin and egg phosphatidylcholine were used as models. Fusion was monitored by darkfield light microscopy and by freeze-fracture electron microscopy. Osmotic swelling was found necessary for fusion between membrane ghosts following PEG treatment. The sample with the highest fusion percentage was sealed ghosts incubated in hypotonic media after at least 5 min of treatment in <25% PEG. At similar osmolarity, glycerol, dextran and PEG produced progressively more pronounced intramembranous particle (IMP) patching, correlating with their increasing fusion percentages. The patching of IMP preceded cell-cell contact, and occurred without direct PEG-protein interaction. The presence of cytoskeletal elements in small vesicles had no significant effect on fusion, nor on the aggregation of intramembranous particle (IMP) upon PEG treatment. Disrupting the membrane by lysolecithin, dimethylsulfoxide, retinol or mild sonication resulted in the fragmentation of ghosts without an increase in fusion percentage. The purity of the commercial PEG used had no apparent effect on fusion. We concluded that the key steps in PEG-induced fusion of cell membrane are the creation of IMP-free zones, and the osmotic swelling of cells after the formation of bilayer contacts during the PEG treatment. Cell cytoskeleton affects PEG-induced fusion only to the extent of affecting IMP patching.     

The biological relevance of HPLC-purified vasoactive intestinal polypeptide monoiodinated at tyrosine 10 or tyrosine 22

Three major forms of monoiodinated VIP (M125I-VIP) were isolated after chloramine-T iodination and HPLC purification. The iodinated tyrosine residue was located in each form of M125I-VIP using arginase C and trypsin digestion for obtaining defined fragments containing only one tyrosine residue. The HPLC isolated iodinated fragments thus obtained were used for HPLC comigration studies with iodinated synthetic C and N terminal VIP fragments and for amino acid analysis. The first two eluting peaks 1 and 2 are (M125I-Tyr10-VIP); peak 1 has an oxidized methionine; peak 3 is a (M125I-Tyr22-VIP) which also has an oxidized methionine. A reduced counterpart of peak 3 named peak 4 was isolated by further HPLC analysis. The ability of the different species of M125I-VIP to stimulate adenosine cyclic 3',5'-phosphate (cAMP) production in transformed colonic cells in culture (HT-29) was compared to that of native VIP. The mean potencies of the M125I-VIP species expressed as a percentage relative to the potency of native VIP were, peak (1): 0.98; (2): 0.84; (3): 1.38; (4): 1.48, in the range of concentrations tested (2-60 pM). The M125I-Tyr22-VIP are significantly more active than native VIP (P less than 0.01). Oxidation of methionine or iodination of tyrosine 10 does not significantly modify the biological activity of VIP. We conclude that iodination of Tyr-22 located in the apolar helical COOH-terminal of VIP increases the effectiveness of VIP interaction with its receptors. Thus the tyrosyl residue and the localized hydrophobic features of VIP are critically involved in the function of this neurotransmitter.     

楝科物质对亚洲玉米螟幼虫取食和生长发育的影响

近年来植物成分对昆虫行为和生长发育的影响很受人们重视。对印楝(Azadirachta indica)的研究证明其含有多种杀虫物质(Schmutterer和Ascher等,1981)。国外报道与印楝为近缘种的苦楝(Melia azadirach)也对昆虫有拒食和干扰生长发育的作用(Schmutterer,1981;Tu和Rueda等,1981),并从中分离出了多种活性物质(Cox,1981)。我国也曾研究应用苦楝防治害虫(中国土农药志编辑委员会,1959),最近证明川楝(Melia toosendan)中成分对水稻三化螟有内吸致毒和拒食作用(赵善欢和张     

诱导茄链格孢菌分生孢子形成的新技术

本文报道诱导茄链格孢菌(Alternaria solani)分生孢子形成的一种新技术。生长在马铃薯-葡萄糖-琼脂(PDA)上两天的茄链格孢菌琼脂块移接到玉米培养基上,置于日光灯下照射,诱发分生孢子梗生长。然后,再放在18℃下黑暗培养。12小时后,在菌丝块表面有大量的分生孢子形成。成熟的茄链格孢菌分生孢子用蒸馏水洗脱。     

ATF4在内质网应激调控成骨分化中的作用

为避免内质网中未折叠蛋白质的过度累积,真核细胞能激活一系列信号通路来维持内质网稳态,这个过程称为内质网应激。在骨生长发育中,适宜的内质网应激有助于成骨细胞、破骨细胞和软骨细胞的生长,可以促进骨髓间充质干细胞向成骨细胞分化。而过度的内质网应激会抑制成骨分化,严重的甚至导致骨质疏松、成骨不全等相关骨病的发生。内质网应激时可激活未折叠蛋白质反应,其主要是通过PERK/eIF2α/ATF4信号通路,上调转录激活因子4(ATF4)的表达。ATF4位于许多成骨分化调节因子的下游,是促进成骨分化的关键因子,在内质网应激对成骨分化的调节中发挥重要作用。在成骨分化过程中,适宜的内质网应激能通过激活PERK信号通路,诱导ATF4表达增加,进而上调骨钙素、骨涎蛋白等成骨所必需基因的表达,促进成骨分化。过度的内质网应激会激活ATF4/CHOP促凋亡途径,并导致Bax、胱天蛋白酶等凋亡信号分子的大量产生,进而导致细胞凋亡,抑制成骨分化。由于ATF4在ERS和成骨分化中的重要作用,ATF4在骨质疏松、成骨不全等骨相关疾病的治疗中具有重要意义。本文通过综述ATF4在内质网应激调控成骨分化中的作用机制,为相关骨性疾病治疗提供理论依据。