Environmental and endogenous control of diapause inTrichogramma species

The 1st feature revealed typical for diapause phenomena inTrichogramma species is the interaction of environmental conditions in both parental and filial generations in induction of diapause in the latter. Lowered temperature during larval development is the ultimate factor evoking diapause in pronymphs but the norm of this thermal reaction is not fixed but varies depending on photoperiod and temperature in the previous generation due to maternal influence. Short day and in some cases high temperature in parental generation enhance tendency to diapause in the progeny. Unlike maternal influence the development to filial generation itself is not (or almost is not) governed by its own photoperiodic reaction. The 2nd typical feature revealed is the occurrence of endogenous process running in the sequence of generations and causing changes in the diapause tendency and underlying reaction norms even under constant rearing conditions.      

盐诱导脯氨酸累积过程中亚胺环己酮的抑制作用

微生物中控制脯氨酸合成的渗透调节基因(osm基因)的转移成功及其抗渗透胁迫能力的提高(Csonka 1980,1981,Le Rudulier和Valentine 1981),启发科学家们把注意力投向高等植物,特别是有经济价值的作物(Bodnar等1989,Nelson等1988,1989,Sanada等1989,Higgins等1987)。采用蛋白质合成抑制剂亚胺环     

豌豆叶绿体脂氧合酶活性与叶片衰老及膜脂过氧化作用的关系

豌豆叶绿体脂氧合酶(LOX)活性在连体叶片衰老过程中变化不大。ABA处理离体叶片2d叶绿体LOX活性升高,处理时间延长活性下降。抗氧化剂α-生育酚、谷胱甘肽、没食子酸丙酯抑制豌豆叶绿体LOX活性。脂质过氧化产物丙二醛对豌豆叶绿体LOX和大豆纯LOX-1的活性均有抑制作用,大豆LOX-1能促进离体豌豆叶绿体膜脂过氧化作用。因此,豌豆叶绿体LOX可能参与叶片衰老过程中叶绿体膜结构和功能的改变,又受膜脂过氧化产物的制约。     

Relationship between radiation induced adaptive response in human fibroblasts and changes in chromatin conformation

Chromatin conformation changes in the normal human fibroblasts VH-10 were studied by the method of anomalous viscosity time dependence (AVTD). Gamma-irradiation of cells in a dose range of 0.1–3 Gy caused an increase in maximal viscosity of cell lysates. Conversely, irradiation of cells with low doses of 0.5 or 2 cGy resulted in a decrease in the AVTD peaks with a maximum effect approximately 40 min after irradiation. The same exposure conditions were used to study a possible adaptive effect of low doses, measured by changes in cell survival. A primary dose of 2 cGy caused significant modification of cell response to a challenge dose. Approximately 20% protection to challenge doses of 0.5 Gy (p < 0.003), 2 Gy (p < 0.02) and 2.5 Gy (p < 0.002) was observed. However, the direction of this effect (adaptation or synergism) was found to be dependent on a challenge dose. The combined effect of 2 cGy and 1 Gy was significantly synergistic, while no modification was observed for 1.5 Gy and 3 Gy. A partial correlation was found between the AVTD changes and cell survival when the combined effect of a primary dose of 2 cGy and challenge dose was examined. The dose of 2 cGy alone increased survival by 16% (p < 0.0003). These results suggest that the low-dose induced effects on survival may be related to chromatin reorganization.     

Effects of social conditions on Juvenile Hormone mediated reproductive development in Bombus terrestris workers

Abstract. During the annual life cycle of the bumble bee Bombus terrestris (L.) colony, there is a stage characterized by worker reproduction in the presence of the queen. It has been proposed that this is a result of a decrease in queen inhibition. This hypothesis was examined by studying the effects of queens taken from colonies at different stages of development on several aspects of worker physiology and behaviour: rates of Juvenile Hormone (JH) release in vitro , ovary development, and behaviour associated with reproduction. After optimizing and validating the radiochemical assay for JH release for bumble bee workers, we found that queenless workers had significantly more developed ovaries and higher rates of release of JH than did queenright workers, confirming and extending previous findings that suggest that bumblebee ovarian development is under JH control. Mated queens, separated from their colony and brood, can have the same inhibitory effect on the reproductive development of callow workers. In contrast, workers confined with virgin queens or in queenless groups demonstrated a significantly higher rate of release of JH, overt aggression and threatening behaviours. However, there were no differences in rates of release of JH between workers confined in groups in the laboratory with queens taken from colonies either before or after the onset of worker reproduction. Furthermore, overt aggression and threatening behaviours were similar and low in both types of groups. These results gave no support to the hypothesis that a decrease in queen inhibition is associated with the onset of worker reproduction. We also show that young workers reared in colonies either before or after worker reproduction occurs, or in queenless colonies, all demonstrated similar, low rates of release of JH. These results suggest that older workers may inhibit the corpora allata of younger workers in queenless colonies.     

电刺激大鼠外侧缰核对延髓甩尾相关细胞的活动和甩尾反射的影响

在浅麻醉大鼠上,在延髓腹内侧结构内观察到三种具有不同放电类型的细胞,即乃尾前放电骤停的撤反应细胞,甩尾前放电骤增的给反应细胞和甩尾无关的中性细胞。电刺激外侧缰核可抑制撤反应细胞的自发放电,加强给反应细胞自发放电,从而易化两类细胞的甩尾相关反应,同时易化伤害刺激引起的甩尾反射。实验结果说明,外侧缰核对节段性防御反射有易化作用,这种易化作用可能是通过延髓内撤反应和反应细胞的协同活动而实现的。     

寄主植物对瓜蚜酯酶活性及其耐药性的影响

寄主植物对瓜蚜无翅胎生雌蚜体重、体色、体内酯酶活性均有明显影响。取食笋瓜、南瓜、瓠子、黄瓜和冬瓜的瓜蚜,体重依次增加,体色渐深,而体内羧酸酯酶活性依次渐低。取食不同奇主植物的瓜蚜对杀虫剂的耐药性与其体内酯酶活性呈正相关。瓜蚜体内羧酸酯酶活性（X）与乐果对瓜蚜的LC50（Y）附会Y=8．3827X－67．8530（r=0．952）,与功夫菊酯对瓜蚜的LC50（Y）附合Y=1．040X－28．89（r=0．985）的线性关系。     

蔷薇属38个野生种果实的维生素含量及其与分组的关系

对蔷薇属 (Rosa) 38个野生种果实 (以下简称蔷薇果 )的经济性状进行了分析 ,并测定了 VC、VE 和胡萝卜素等重要维生素的含量。蔷薇果 VC 含量在该属种间差异很大 ,以秦岭蔷薇 (R.tsinglingensis)的含量为最高 (2 576mg/ 1 0 0 g) ,德钦蔷薇 (R.deqenensis)的含量为最低 (49mg/ 1 0 0 g)。胡萝卜素含量种间差异明显 ,以软条七蔷薇 (R.henryi)的含量为最高 (1 9.2 4 mg / 1 0 0 g) ,黄刺玫 (R.xanthina)的含量为最低 (0 .0 6 mg/ 1 0 0 g)。 VE 含量种间差异较小 ,在 1 .34 mg/ 1 0 0 g(黄刺玫 )至 3.86 mg/ 1 0 0 g(硕苞蔷薇R.bracteata)之间。对蔷薇亚属 54种野生种果实重要维生素含量的统计分析表明 ,维生素含量与分组具有一定相关性 ,尤以 VC 含量与分组的相关性最为明显 ,桂味组和小叶组 Vc含量很高 (均值都高于 1 80 0mg/ 1 0 0 g) ;合柱组、月季组、木香组和硕苞组含量很低 (均值都在 30 0 mg/ 1 0 0 g以下 ) ,芹叶组除宽刺蔷薇 (R.platyacantha) VC含量很高外 ,其余种类含量都很低 (均值为 1 90 mg/ 1 0 0 g)。胡萝卜素含量与分组也具有一定相关性 ,桂味组、芹叶组、合柱组和硕苞组的胡萝卜素含量较高 ,均值在 6 mg/ 1 0 0 g以上 ;月季组、小叶组和木香组含量较低 ,均值在 0 .4mg/ 1 0 0 g以下。V     

水稻幼芽细胞生物膜上的赤霉素结合蛋白的结合特性

在水稻 (Oryza sativa)幼芽中存在膜结合的赤霉素结合蛋白 ,其与 GA3 结合的平衡解离常数(Kd)为 6.5× 1 0 -8mol/ L,总浓度为 0 .3 pmol· mg-1 蛋白质。结合蛋白与 GA3 结合活力在 0℃时比 2 5℃时高 1 4 0 %。它与 GA3 结合的最适 p H为 5。 GA3 与此结合蛋白的结合量随反应时间延长而增加 ,1 h达最大值 ,以后又逐渐下降。 IAA、ABA可与 GA3 竞争赤霉素结合蛋白。     

滇产薄荷的化学研究

研究了滇产３８个薄荷样品,测定了样品的得油率及化学成分。滇产薄荷的得油率在０．１８％￣０．５２％之间。从挥发油中鉴定出了１００多种化学成分,主要含醇、酮、酯、萜烯类化合物。栽培的家薄荷挥发油富含香芹酮、柠檬烯,其化学分类属于香芹酮系列。野生薄荷挥发油富含薄荷醇和薄荷酮,属于薄荷酮系列;部分野薄荷样品,富含香芹酮、环氧辣薄荷烯酮或芳樟醇,属于混合系列。