用于RNA干扰研究的大肠杆菌表达系统的条件优化

选取在E.coli中对于dsRNA表达比较重要的3个因素,即诱导时间、诱导温度和诱导剂IPTG浓度。利用已经构建好的大肠杆菌E.coli HT115(DE3),并结合正交试验设计研究dsRNA在HT115(DE3)内的最优表达条件。结果表明,工程菌在诱导时间8 h、诱导温度30℃、诱导剂浓度10.0 mmol/L的培养条件下所得到的dsRNA表达量最大。     

Studies on the acetylcholinesterase of Anopheles albimanus resistant and susceptible to organophosphate and carbamate insecticides

Acetylcholinesterase from fourth instar Anopheles albimanus larvae was studied in vitro. The acetylcholinesterase from both the resistant and susceptible strains behaved as a single enzyme “type,” with straight pseudo first-order insecticide inhibition lines which intersected the Y axis at 100%. The enzyme from resistant larvae was more slowly inhibited than the susceptible enzyme; bimolecular rate constants (k_i) differed by approximately 1.2- to 6-fold for a range of organophosphorous compounds and 17- to 1570-fold for the carbamates. There was a good correlation between the levels of resistance and the acetylcholinesterase inhibition rates.     

Growth of pot roses and post-harvest rate of water loss as affected by air humidity and temperature variations during growth under continuous light

The effect of diurnal variations in air humidity and temperature under continuous lighting period (LP) on growth, flowering and water loss were studied in two pot-rose cultivars.     

黄瓜对热处理的热受性及生理反应

本文通过42℃、37℃22个处理和对照20℃对黄瓜的叶绿素含量、果实硬度、可滴定酸和可溶性固形物、Vc含量以及热处理过程中呼吸速率、MDA含量，SOD、POD、CAT活性的变化，研究了热处理对黄瓜品质和生理的影响，热处理可以促进果实硬度的下降、叶绿素的降解、Vc含量和可滴定酸的降低，同时促进呼吸速率升高、丙二醛的积累，促进膜脂保护酶POD、SOD的升高．从黄瓜热受性研究表明“新丹四号”黄瓜42℃处理时间要控制在12h以内，37℃处理时间控制在24h以内为宜．为热处理在果蔬采后方面的应用和进一步研究提供借鉴。     

巢式PCR快速鉴定鸡传染性支气管炎病毒的研究

鸡传染性支气管炎病毒（ＩＢＶ）经鸡胚增殖后,直接用尿囊液提取ＲＮＡ后反转录成ｃＤＮＡ,用ＩＢＶ基因３’端的ＵＴＲ１－／ＵＴＲ２＋和ＵＴＲ３－／ＵＴＲ４＋两对引物进行巢式ＰＣＲ,所检测的４个ＩＢＶ标准参考株和１６个ＩＢＶ野毒株均得到了预期的１７４ｂｐ大小的片段,而鸡新城疫病毒（ＮＤＶ）,鸡传染性法氏囊病毒（ＩＢＤＶ）及正常鸡胚尿囊液经同样处理没有可见片段出现。本试验不需纯化册毒只需０５ｍｌ病毒尿囊液即可在２４小时内得到准确的试验结果。这表明与其它ＩＢＶ鉴定方法相比,该法具有快速、灵敏、特异的优点。     

鹿茸多肽对冈田酸诱导的小鼠海马神经元HT22细胞损伤模型中PI3K、AKT、Caspase-9表达的影响

目的观察鹿茸多肽对冈田酸(OA)诱导的小鼠海马神经元HT22细胞损伤模型中磷脂酰肌醇-3激酶(PI3K)、蛋白激酶B(AKT)、半胱氨酸蛋白酶-9(Caspase-9)表达的影响,探讨鹿茸多肽对HT22细胞损伤模型的保护作用机制。方法采用含10%胎牛血清(FBS)培养液(DMEM/F12)传代培养HT22细胞7d后,分为正常对照组、二甲基亚砜(DMSO)对照组、OA细胞损伤模型组、鹿茸多肽高、中、低剂量组。正常对照组给予含10%FBS的DMEM/F12,DMSO对照组给予DMSO终浓度<0.01%的DMEM/F12,OA细胞损伤模型组给予10nmol OA的DMEM/F12,鹿茸多肽高、中、低剂量组分别给予50、500、1000μg/ml的DMEM/F12,于37℃、5%CO2条件下孵育24h。利用噻唑蓝(MTT)比色法检测细胞存活率,酶联免疫法(ELISA)检测各组实验细胞内PI3K、AKT含量,蛋白质印迹法(Western Blot)检测各组实验细胞内PI3K、AKT、Caspase-9表达水平。结果MTT比色法检测结果表明,与OA细胞损伤模型组比较,鹿茸多肽能够明显提高细胞存活率(P<0.05);ELISA检测结果表明,与OA细胞损伤模型组比较,鹿茸多肽能够明显提高受损HT22细胞内PI3K、AKT含量(P<0.05或P<0.01);Western Blot检测结果表明,与OA细胞损伤模型组比较,鹿茸多肽能够明显提高受损HT22细胞内PI3K、AKT、Caspase-9表达水平(P<0.05或P<0.01)。结论鹿茸多肽对OA诱导的HT22细胞损伤模型具有保护作用,作用机制可能与调节受损HT22细胞内PI3K、AKT、Caspase-9表达水平相关。     

Mitochondrial changes during storage of untreated or CIPC-treated potatoes

During storage of potato tubers (Solanum tuberosum L., var. Bintje), important changes appear which affect respiratory control, $\text{ADP}\text{O}$, intensity of O₂ consumption in the presence of different substrates, and NAD⁺ dependence, In mitochondria extracted under strictly similar conditions, from patato tubers stored at 4°C, the respiratory control (RC) maintains a value near 4 for 4 to 5 months. It then declines progressively to low values. At 20°C, a stable RC of 4 can be observed for several months, which then decreases at the end of dormancy. Then, the RC increases sharply; at this stage, $\text{ADP}\text{O}$ are abnormally low, and, some time later, NAD⁺ dependence disappears. Mitochondria treated with 250 μM chlorpropham show a 50% inhibition of the electron transfer with exogenous NADH as substrate. After tuber treatment with 1% chlorpropham, sprouting is inhibited for several months. The activities of mitochondria extracted from such tubers remain unaffected by the treatment. The use of this phenylcarbamate for potato tuber treatment permits obtaining functional mitochondria from tubers after a slightly longer period of storage.     

盐分胁迫下喷施γ-氨基丁酸对水稻秧苗生长的影响

为探究喷施γ-氨基丁酸（GABA）对不同程度盐分胁迫下水稻秧苗生长的影响,以天津主栽粳稻品种天隆优619为研究对象,在秧苗采用穴盘培育到3叶1心时,分别用0、25、50、75、100 mmol/L NaCl溶液水培,并设置叶面喷施4 mmol/L GABA处理,以叶面喷水作为对照组,调查水稻的生长指标和3种抗氧化酶活性。结果表明,随着盐分胁迫程度的增加,水稻的株高增量、叶面积呈下降趋势,死叶率、根系干鲜比、叶片POD和SOD酶活性呈上升趋势,根系活力和叶片APX酶活性呈先升后降趋势。在相同盐分胁迫下,与不喷施GABA对照相比,喷施GABA处理表现为：株高增量增加1.7%~32.4%,死叶率降低1.6%~23.3%,根干质量减少9.3%~22.0%,根系活力增加1.2%~94.4%,叶片POD、SOD和APX酶活性分别增加5.0%~20.8%、9.8%~17.3%和7.2~64.4%。可见,叶面喷施4 mmol/L GABA能够提高供试水稻的耐盐性,促进同化物优先向地上部分配。     

不同粒度的砂土对HT200磨损性能的试验研究

在磨料磨损试验机上,考察了不同粒度的土壤对灰铸铁HT200磨损性能的影响,用扫描电子显微镜观察HT200试样磨痕表面的形貌,分析磨痕形成机理.结果表明:随着土壤粒度的增大,HT200材料磨损量随之增大;显微观察发现HT200磨损表面形成隆起与凹谷,还有少量沟槽;土壤对HT200的磨损主要是脆化剥落形成的,塑性变形较轻.