4PU—30对水稻叶片的保绿效应

4PU—30对水稻离体叶圆片和抽穗后整株叶片的衰老均有明显的延缓效应,在离体叶圆片培养中其效应比6—BA大。     

豇豆叶片衰老过程中多胺氧化酶活性的变化（简报）

豇豆幼苗的连体和离体叶片衰老过程中多胺氧化酶（PAO）活性与叶绿素和蛋白质的含量都呈下降趋势,它们的降幅依次是：PAO活性大于叶绿素含量大于蛋白质含量;用氨基胍抑制离体叶圆片PAO活性,不能延缓叶绿素和蛋白质的含量下降。     

乙酰水杨酸处理对猕猴桃果实成熟衰老的影响及其作用机理

以不同后熟软化阶段猕猴桃果肉组织圆片为材料 ,在 2 0℃下用 1.0mmol L(pH 3.5 )的乙酰水杨酸(ASP)分别处理 4、12和 2 4h后 ,分析其对果实成熟衰老相关因子的影响。结果表明 ,随着果实成熟衰老 ,内源游离SA下降 ,LOX活性增加 ,超氧自由基 (O- ·2 )生成速率增加 ,乙烯释放量加大 ;ASP处理促使组织内源SA水平的增加 ,降低了O- ·2 生成速率 ,抑制了LOX、ACC合成酶和ACC氧化酶的活性以及乙烯的生成。推测ASP可能作为O- ·2 等自由基清除剂 ,通过负反馈调控LOX途径 ,延缓果实的成熟衰老     

番茄果实成熟过程中钙调素含量变化及其与乙烯生成的关系

应用酶联免疫吸附法(ELISA)测定番茄(Lycopersicon esculentum Mill大红品种)果实成熟过程中钙调素(CaM)含量的变化。果实开始成熟(发白期),CaM含量随着呼吸跃变上升,成熟时(粉红期)达到最大,过熟衰老时则下降。果实内部乙烯浓度、ACC含量及其合成酶活性也随跃变而增加,随过熟衰老而降低。GaM含量在果实不同部位中的分布有明显差异,跃变上升期以子房腔组织含量最高,并由中心向外逐渐降低,外周果皮含量最低。此时用外源乙烯催熟处理促进各部位CaM增加。成熟衰老时子房腔组织首先衰老,CaM含量大为降低,但在中柱和果皮中却高于跃变上升期。外源乙烯促进衰老使CaM下降。Ca~(2+)促进番茄圆片CaM含量增高和乙烯产生,CaM抑制剂CPZ,TFP在降低CaM含量的同时也抑制乙烯的产生。     

茶多酚抑菌作用的研究

茶多酚又名茶单宁、茶鞣质,是茶叶中一类以儿茶素为主的多酚类化合物。已证实它有止渴提神、延缓衰老、抗肿瘤、抑制TPA促癌作用,且是很强的氧化剂。笔者用滤纸圆片和牛津杯法,测试茶多酚对十一种细菌、两种酵母、四种霉菌等三大类微生物的抑制作用,以探讨茶多酚新的作用和开拓应用新途径。     

细胞壁中富含羟脯氨酸蛋白质与烟草叶细胞扩大生长的关系

从生长良好的烟草叶钻下圆片进行离体培养。发现在含有2 ppm 6BA的MS培养液中加入游离的羟脯氨酸,能明显地抑制烟草叶圆片的扩大生长.羟脯氨酸浓度在0.05 mM到0.8 mM范围内与圆片的扩大生长呈显著负相关。用~(14)C-脯氨酸餵饲培养了3天的烟草叶圆片,发现在无激素的MS培养液中和在含有2 ppm 6BA+0.3 mM羟脯氨酸的MS培养液中生长缓慢的圆片,其放射性掺入圆片和掺入蛋白质的量均低于在含2 ppm 6BA的MS培养液中迅速生长的圆片。然而,生长缓慢的圆片,其细胞质水溶性部分和细胞壁部分羟脯氨酸/脯氨酸之比值却都高于迅速生长的圆片。这意味着富含羟脯氨酸蛋白质的大量形成可能不利于细胞的扩大生长。细胞壁中放射性的掺入量随餵饲时间的延长而增加,羟脯氨酸/脯氨酸比值也随餵饲时间的延长而提高,这说明在细胞壁中亦可能有脯氨酸的羟基化过程发生。     

介绍一种饲养蚜虫的方法——新的叶子圆片法

<正> Adams and van Emden(1972)介绍了多种饲养蚜虫的方法,其中之一就是Hughes andWoolcock(1965)报道的叶子圆片法(以下称老的叶子圆片法)。即将切割成的叶子圆片飘浮在修改了的Hoagland-Sayder植物营养液上,蚜虫则在叶子圆片上取食。这种方法在蚜虫试验工作中,一直被广泛应用。1981年,R.J.Milner博士对老的叶子圆片法进行了改进(以下称新的叶子圆片法)。作者在近几年蚜虫、蚜茧蜂的研究工作中,对新的叶子圆片法的效果进行了考查,并多次在试验工作中应用此法饲养蚜虫(如Lin and Hughes,1984),发现该法简便易行、效果良好。作者还看到用这种方法饲养叶螨、蚧虫,同样方便可行。今将新的叶子圆片法的装置和应用方法作一介绍。     

ONPG圆片的制备和应用

用国产材料及试剂,自制β－半乳糖甙酶试验用ＯＮＰＧ圆片。经过菌种试验和临床实验室应用证明,使用此种圆片与常规试管法和国外的同类圆片进行对比试验,所得结果完全一致。此种圆片使用方便,易于保存,可以长期使用,且节约试剂,达到国外同类制品的质量,有助于保证和提高细菌鉴定工作质量。     

温度对UV-B诱导的烟草叶圆片DNA损伤的影响

环丁烷嘧啶二聚体(CPD)和6-4光产物(6-4PP)是两种主要的UV-B诱导的DNA光损伤产物。利用单克隆抗体酶联免疫吸附分析法(ELISA),研究了温度对UV-B诱导的烟草叶圆片DNA损伤的影响。室温(24℃)条件下,UV-B处理引起了烟草叶圆片DNA中CPD和6-4PP的积累。0℃条件下,UV-B处理的烟草叶圆片DNA中CPD和6-4PP的积累比室温下分别降低了9.8%和12%。UV-B诱导的DNA损伤曾被认为是纯粹的光化学过程而与不受温度影响,而本实验结果表明,UV-B诱导的烟草叶圆片DNA形成CPD和6-4PP的过程具有温度依赖性。这一特性有利于植物对全球变化的适应,因而具有重要的生态学意义。     

ca2 +对苹果果实细胞膜透性 保护酶活性和保护物质含量的影响

CaCl2处理“金冠”苹果果肉圆片,明显地增加Ca2+含量,降低K+外渗。不同浓度Ca2+程度不同地提高圆片超氧化物歧化酶、过氧化氢酶活性和谷胱甘肽、抗坏血酸含量,降低H2O2含量和相对电导率。本文认为：Ca2+能提高保护酶活性和保护物质含量,有利于保护细胞膜结构。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Determination of stoichiometry of radioiodination of proteins

A sensitive method for the detection of small quantities of hydrophobic antioxidant free radical scavengers such as butylatedhydroxytoluene (BHT) and butylatedhydroxyanisole (BHA) in aqueous samples is described. The procedure involves extraction of the hydrophobic free radical scavenger into an organic solvent phase, followed by the subsequent reaction of an aliquot of this extract with the stable cation radical tris(p-bromophenyl)amminium hexachloroantimonate (TBACA). In experiments with BHT and BHA, the loss of TBACA absorbance at 730 nm was found to be linearly proportional to the amount of antioxidant added, with quantities of BHT as small as 200 pmol being easily detectable. In aqueous suspensions of dimyristoylphosphatidylcholine vesicles, assays of the aqueous BHT concentration showed that BHT partitioned strongly into the membrane phase, achieving very high BHT/phospholipid ratios. For a given concentration of BHT, partitioning into the membrane phase was greater in large, multilamellar liposomes than in either small, single-walled vesicles or in purified rat brain synaptic vesicle membranes. Direct assay of BHT and BHA in phospholipid membranes, however, was complicated by a nonspecific interaction between TBACA and the phospholipid.