蒜头中SOD的提取研究

蒜头含有丰富的超氧化物歧化酶(SOD),采用磷酸缓冲液,通过盐析、超滤、冷冻干燥等工艺提取纯化SOD,得出SOD提取的最佳工艺条件:缓冲液体积35 m L(对于30 mg新鲜去外膜的蒜瓣)、pH值7.7、超声提取时间10 min及(NH4)2SO4饱和度为45%。实验结果对进一步优化SOD酶的提取纯化工艺以及酶的临床应用具有指导意义。     

重组蛹虫草超氧化物岐化酶脱辅基蛋白的表达、纯化及其活性重建

目的表达并纯化重组蛹虫草超氧化物歧化酶脱辅基蛋白,并考查各种金属离子对其活性重建的作用。方法用不含Cu2+和Zn2+的培养基培养重组菌株,并表达重组蛋白,采用DEAE-FF和CM-52进行纯化;在脱辅基蛋白溶液中加入Cu2+、Mn2+、Mg2+、Ni2+或Ag+,测定SOD酶活力的变化。结果蛹虫草脱辅基Cu,Zn-SOD在不含Cu2+和Zn2+的培养基中得到表达,纯化后的样品经SDS-PAGE分析,在相对分子质量17000处出现单一条带,经活性电泳分析无酶活力;脱辅基蛋白活性重建的最适宜Cu2+浓度为0.005mmol/L,但其紫外吸收图谱与天然SOD不同;0.1mmol/L的Mn2+、Mg2+、Ni2+、Ag+重建的酶活力远低于Cu2+重建的cm-SOD的酶活力。结论已成功表达并纯化了蛹虫草脱辅基Cu,Zn-SOD,各种金属离子只能有限地重建脱辅基Cu,Zn-SOD的活性。     

啤酒酵母泥中一种新型SOD的提取

啤酒酵母泥以异丙醇破壁处理,以磷酸钾缓冲液提取超氧化物歧化酶(SOD),通过单因素和正交实验优化了提取条件。结果表明,提取SOD的最佳条件是:以100%浓度异丙醇破壁处理150 min,以pH 5.0磷酸钾缓冲液为提取剂,液料比36 m L/g。在此条件下,SOD的得率为1 257.2 U/g。纯化后的SOD酶液主要含有分子量大小为25.46 k D和49.53 k D两种蛋白,其中分子量25.46 KD的蛋白与NCBI蛋白质数据库中baker’s yeast中SOD的分子量相符合,该酶理论等电点为8.49,与中文文献中报道的SOD均不同,是一种新型SOD。     

啤酒酵母泥中一种新型SOD的提取

啤酒酵母泥以异丙醇破壁处理,以磷酸钾缓冲液提取超氧化物歧化酶(SOD),通过单因素和正交实验优化了提取条件。结果表明,提取SOD的最佳条件是:以100%浓度异丙醇破壁处理150 min,以pH 5.0磷酸钾缓冲液为提取剂,液料比36 m L/g。在此条件下,SOD的得率为1 257.2 U/g。纯化后的SOD酶液主要含有分子量大小为25.46 k D和49.53 k D两种蛋白,其中分子量25.46 KD的蛋白与NCBI蛋白质数据库中baker’s yeast中SOD的分子量相符合,该酶理论等电点为8.49,与中文文献中报道的SOD均不同,是一种新型SOD。     

从大蒜萃余物中提取超氧化物歧化酶研究

通过对大蒜中优先提取超氧化物歧化酶(SOD)与超临界CO2萃取蒜油后提取SOD的对比实验,结果表明,从大蒜萃余物中提取的SOD相对于优先从新鲜大蒜中提取的SOD活力相差不到10%。说明萃余物仍有很大的利用价值。     

膜分离提取大蒜SOD及其水溶性多肽研究

采用膜分离技术,考察磷酸缓冲液pH值、浸提时间、热变性温度、热变性时间因素对SOD活性的影响,提取大蒜中的SOD及其水溶性多肽。经正交试验确定了提取大蒜SOD的最佳提取条件:缓冲液pH为7.8,提取时间为60min,热变性温度60℃,热变性时间为20min,在此条件下,SOD活力达到了411.92 U/g。产物用SDS-PAGE分析,得出8条蛋白多肽条带。     

蛹虫草多糖提取分离方法的研究进展

蛹虫草含有虫草素、虫草酸、虫草多糖等多种高药理价值的化合物。其中蛹虫草多糖的含量为4%～10%,是其主要有效成分,具有抗癌、抗氧化、增强免疫等作用。本文综述了蛹虫草多糖的提取、分离方法的研究进展,为后续药理研究以及产业化生产提供参考。     

石榴叶超氧化物歧化酶的纯化及性质研究

利用有机溶剂分级沉淀法从石榴叶中分离出超氧化歧化酶(SOD),研究了分离纯化的最佳工艺条件,并对其性质进行了探讨。结果表明,当石榴叶(g)与磷酸缓冲液(mL)之比为1∶2,磷酸缓冲液pH值为7.6,提取时间为1.5 h。氯仿-乙醇混合物量为提取液的0.25倍,丙酮量为粗酶液的1倍时,分离效果最佳。温度0~60℃,pH 4~9范围内酶的活性稳定。过氧化氢和乙醇-氯仿试验表明,该酶属Cu.Zn-SOD。研究结果为SOD提供了新的酶源。     

响应面分析法优化蛹虫草液体发酵培养基

目的运用响应面分析法对蛹虫草液体发酵培养基进行优化,以提高蛹虫草发酵液中抗肿瘤活性物质的含量。方法以对肝癌细胞抑制率为指标,首先进行单因素试验优选出培养基中最佳氮源及其浓度以及葡萄糖和磷酸二氢钾(KH_2PO_4)最佳浓度;再采用响应面分析法确定关键因素之间的配比。结果蛹虫草最佳液体发酵培养基为:葡萄糖浓度20.22 g/L,蛋白胨浓度17.57 g/L,KH2_PO_4浓度0.92 g/L,硫酸镁浓度0.5g/L,在该条件下,肝癌细胞抑制率为70.121%,与模型预测值(70.938%)相接近。结论运用响应面分析法对蛹虫草液体发酵培养基进行了优化,从根本上提高了各活性物质的产量,对后续蛹虫草抗癌活性的研究具有重要意义。     

从紫皮大蒜萃余物中提取SOD

通过对紫皮大蒜中优先提取SOD与超临界CO2萃取蒜油后提取SOD的对比研究,实验结果表明,从紫皮大蒜萃余物中提取的SOD相对于优先从新鲜紫皮大蒜中提取的SOD活力相差不到10%。说明紫皮大蒜萃余物仍有很大的利用价值。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。