N-酰基高丝氨酸内酯降解酶的抗体制备与鉴定

根据已报道的aiiA基因及attM基因序列设计引物,分别从蜡质芽孢杆菌(Bacillus cereus)和土壤根癌农杆菌(Agrobacterium tumefaciens)中PCR扩增获得aiiA基因及attM基因,构建蛋白表达载体pET30a-aiiA及pET30a-attM,在大肠杆菌BL21中诱导表达。利用AiiA解酯酶蛋白和AttM解酯酶蛋白在SDS-PAGE中对应的产物直接成兔免疫,提取血清进行ELISA和Western Blot检测。SDS-PAGE检测发现aiiA基因及attM基因能高效表达AiiA解酯酶蛋白和AttM解酯酶蛋白。ELISA检测结果表明,抗体含量高,稀释106倍依然为有效值。Western Blot检测结果表明抗体可特异性结合目的蛋白。应用检测结果表明抗体血清能检测到N-酰基高丝氨酸内酯降解酶相关基因的产物,在验证群体感应和群体淬灭等方面将具有应用价值。

米糠膨化浸出技术的应用

米糠中解酯酶和脂肪氧化酶的存在 ,使米糠的储运、保鲜十分困难 ,挤压膨化法是对米糠进行杀酵保鲜的有效方法。通过对米糠的组成与特性的分析和研究 ,着重介绍了米糠膨化的目的、作用 ;膨化机的操作方法和操作技巧 ;干式膨化和湿式膨化的优缺点 ;米糠膨化料浸出的工艺技术和操作方法。

米糠预处理工艺介绍

米糠经预处理后既可钝化解酯酶活性,提高储存稳定性,又可获得孔隙度、渗透性良好、大小适中的米糠料粒,为后续浸出生产创造有利条件。常用的米糠预处理工艺主要有干式膨化、湿式膨化和米糠造粒3种,本文介绍了这3种工艺的操作要点、影响因素、各自的优缺点和适用场合。

Activities of lipoxygenase and phenylalanine ammonia lyase in poplar leaves induced by insect herbivory and volatiles

A study was conducted to explore the defense response in woody plants after insect herbivory. The activities of two enzymes, lipoxygenase （LOX）, a key enzyme ofjasmonate （JA） pathway, and phenylalanine ammonia lyase （PAL）, a rate-limiting enzyme of phenyl- propanoid pathway, were measured in the leaves of one-year-old poplar （Populus simonii × P. pyramidalis ＇Opera 8277＇） cuttings after Clostera anachoreta larvae attack. The results show that the increased activities of LOX and PAL were found not only in the leaves wounded by C. anachoreta larvae but also in their tipper systemic leaves, indicating that JA and phenylpropanoid pathways were activated, and the defense response was stimulated systemically. The increase in LOX and PAL activities in neighboring intact poplar cuttings sug- gested that there exists the interplant communication between poplar plants mediated by the herbivore-induced volatiles. Methyl jasmonate （MeJA） was also proved to be an airborne signal to induce defense response in P simonii × P pyramidalis ＇Opera 8277＇ cuttings.

Study on Characters of Major Hydrolase Isozymes in Wheat Seeds

ObjectiveThis study aimed to investigate the characters of major hydrolase isozymes in wheat seeds. MethodThe spectra of amylase, esterase and proteolytic enzyme isozymes in the germ, endosperm and radicle were studied in detail during the germination process using the polyacrylamide gel electrophoresis（PAGE）. ResultThe results indicated that isozymes of amylase and esterase changed obviously in the endosperm during the germination, while isozymes of proteolytic enzyme exhibited distinct variation in the germ and radicle. ConclusionThis study provides basic data for effeciently improving the germination rate of crop seeds in the future.

Selection of Strains Producing Lipase with Transesterification Activity and Its Characterization

The interest for lipase production is due to the ability of this enzyme to catalyze some reactions, such as the transesterification. Although industrial biodiesel is produced chemically, there are several problems associated with this technology that can be prevented through the use of lipases. The present work aimed to select microorganisms with potential for production of lipase with transesterification activity. The lipase from Burkholderia cepacia was the one with the most promising results for this type of reaction, showing results of hydrolytic activity at 37 ℃and pH 8.0. The pH and volume of crude enzyme extract that showed favorable for synthesis ofbiodiesel is at about pH 6.0 and 3.75 mL, respectively, which represents approximately 42% of water in the system, ensuring the conversion of nearly 60% to biodiesel.

Biodegradation of Phthalate Esters by a Newly Isolated Acinetobacter sp. Strain LMB-5 and Characteristics of Its Esterase

Phthalate esters （PAEs） are extensively applied in industry, and they migrate to environment during the process of production, employ, and treatment and axe difficult to be degraded in nature. However, some microorganisms could use them as the carbon source to growth. In this study, an Acinetobacter sp. strain LMB-5, capable of utilizing PAEs, was isolated from a vegetable greenhouse soil. The degradation capability of strain LMB-5 was also investigated by incubation in mineral salt medium containing different PAEs, dimethyl phthalate （DMP）, diethyl phthalate （DEP）, di-n-butyl phthalate （DBP）, and di-（2-ethylhexyl） phthalate （DEHP）. The strain could grow well with DMP, DEP, DBP, and DEHP. When the concentration of DBP increased from 100 to 400 mg L-1, the half-life extended from 9.5 to 15.5 h. In the concentration range of DBP, the degradation ability of strain LMB-5 could be described by first-order kinetics. During the biodegradation of DBP, three intermediates, 1,2-benzenedicaxboxylic acid,butyl methyl ester, DMP, and phthalic acid （PA） were detected, and the proposed pathway of DBP was identified. By analysis of bioinformatics, one esterase was cloned from the genome of LMB-5 and expressed in Escherichia coll. It displayed an ability to break the ester bonds of DBP. The enzyme exhibited maximal activity at pH 7.0 and 40 ℃ with DBP as the substrate. It was activated by Cu2＋ and Fe3＋ and had a high activity in the presence of low concentrations of methanol or dimethylsulfoxide （each 10%, volume：volume）. The Acinetobacter sp. strain LMB-5 may make a contribution to the remediation of soils polluted by PAEs in the future.

Influence of electroacupuncture therapy of tonifying the kidney and regulating governor vessel on Aβ related degradation enzymes in the hippocampus of a rat model of Alzheimer's disease induced by Aβ_(1-42)

Objective： To explore influence of electroacupuncture（EA） therapy of tonifying the kidney and regulating governor vessel on amyloid beta（Aβ） related degradation enzymes in the hippocampus of a rat model of Alzheimer＇s disease（AD） induced by Aβ（1-42）.Methods： Forty Wistar male rats were randomly divided into 4 groups： a normal group, a sham operation group, a model group and an EA group, 10 rats in each one. The rats in normal group were normally fed. The rats in sham operation group were bilaterally injected in the hippocampus with 5 μL of saline and they were normally fed after the injection. The rats in the model group and the EA group were bilaterally injected in the hippocampus with 5 μL of Aβ（1-42） on each side. Rats in the EA group received EA of 5 Hz continuous wave at the ＂Bǎihuì（百会 GV20）＂ and bilateral ＂Shènshū（肾俞 BL23）＂ for a duration of 15 min per time every day and continuously for 15 days. After 15 days, the hippocampal expression levels of insulin degrading enzyme（IDE）, lipoprotein（LPL）, transthyretin（TTR）, apolipoprotein E（APoE）,a2 macroglobulin（a2 M） and Aβ（1-42） of the 4 groups were tested by Western blot.Results： Compared with the sham operation group, the expression levels of IDE, LPL, TTR, APoE and a2 M in the hippocampus were significantly lower（P〈 0.05, P〈 0.01） and the expression of Aβ（1-42） was significantly higher（P〈 0.01） in the model group. Compared with the model group, the expression levels of IDE, LPL, TTR,APoE and a2 M in the hippocampus of these rats were significantly lower（P〈 0.05,P〈 0.01）, the expression of Aβ（1-42） was significantly higher（P〈 0.01） in the EA group.Conclusion： EA therapy of tonifying the kidney and regulating governor vessel can enhance the expression of IDE, LPL, TTR, APoE, and a2 M in the hippocampus of AD rats injected by Aβ（1-42）, and may consequently promote the degradation of aβ（1-42） to help improve the pathological manifestations of AD and therefore delay its progression.