致死的

Reactive oxygen species causing DNA oxidative damage comes from two kinds of ways:one is from cellular normal physiological metabolism;the other is from outer environment.Redox-sensitive green fluorescent protein was expressed in Saccharomyces cerevisiae.Recombinant cells were evaluated in monitoring the changes in the redox state of living cells when challenged with toxicologically relevant metal ions NaAsO_2 or Pb(NO_3)_2 by measuring emission intensity at 510 nm with a Hitachi F6500 fluorescence spectrophotometer,roGFP expressed in yeast responded not only to typical membrane-permeant oxidants H_2O_2 and reductants DTT,but also to toxicological metal ion-induced intracellular redox changes in a dose-dependent manner.Moreover,exposure of yeast cells to NaAsO_2 or Pb(NO_3)_2 at concentrations that induced redox changes reported by roGFP caused up to 2～3 fold increases in DNA mutation frequency.This mutagenic effect was largely caused by oxidative stress since blocking the production of hydryl radicals with thiourea significantly reduced the mutation rate as well as delayed the cell death.

本文将对氧化还原状态变化敏感的绿色荧光蛋白roGFP1-R12，在酵母细胞中实现了多拷贝强表达；荧光扫描经强氧化剂H_2O_2和还原剂DTT以及环境中重金属NaAsO_2或Pb(NO_3)_2处理后的酵母细胞悬液，测定510 nm处的荧光发射强度结果显示，表达的绿色荧光蛋白对氧化还原水平敏感，且在510 nm处的荧光强度与一定的重金属浓度呈正相关，即roGFP1-R12在510nm处的荧光发射值随重金属浓度的增高而增强，从而说明重金属对细胞的毒性在一定程度上很可能是通过破坏细胞内的氧化还原平衡发生作用；同时通过该绿色荧光蛋白对胞内氧化还原状态变化的响应情况可以来实时检测环境中的重金属；遗传学的点突变频率及致死率实验数据表明，重金属能导致菌体的点突变频率和致死率升高，且活性氧的清除剂巯基脲能明显降低这种点突变和致死率，说明由重金属引发的这种点突变和致死效应在很大程度上是依赖于重金属对细胞诱导产生的氧化胁迫。

Biological characteristics of the pathogen and the resistance of 13 cultivars of tea plant to tea brown blight were studied by means of natural infection in the field and artificial inoculation in vitro. Resistant cultivars and susceptible cultivars of tea plant were divided. And the resistance mechanism was researched tentatively. The findings are as follows: 1 Some biological characteristics of the pathogenic fungus The experiment result showed: the optimum temperature for the growth of fungus mycelium was from 24 to 27℃, the optimum temperature for sporulation ranged 22 to 30℃. Treated at 54℃ in 10 minutes, the spores didn't germinate. The optimum pH for the growth of the mycelium was 5.1～5.9, the optimum pH for sporulation ranged 5.0～6.0. Light had no much effect on the growth of fungus mycelium, but had much effect on the reproduction of the spore.

首先，研究了茶云纹叶枯病病菌的生物学特性；其次，通过田间抗性调查和室内人工接种鉴定，对 13 个茶树品种进行了抗病性鉴定；第三，在前人研究的基础上，对茶树抗病机理作了更深入的研究，结果发现： 1 病原菌的生物学特性病原菌的分生孢子萌发的最适温度范围为 24～27℃，菌丝生长的最适温度范围为 22～30℃；致死温度为 55℃；菌丝生长的最适 pH 范围为 5.1～5.9，孢子萌发的最适 pH 范围是 5.0～6.0；光照对病菌生长速度及分生孢子萌发影响不大，但对其产孢的影响很大，特别是有光照与无光照处理之间差异显著，光照有利于分生孢子的形成。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。