酶解魔芋飞粉制备高F值寡肽最佳工艺条件的研究

目的:为了得到高F值寡肽,需要对蛋白质进行水解。方法:采用酶法水解魔芋飞粉制备高F值寡肽。通过对蛋白质水解度的测定,确定了碱性蛋白酶和链霉蛋白酶的最佳酶解条件:碱性蛋白酶加酶量0.1%,底物浓度3.75%,pH9.0,水解温度45℃,时间5h;链霉蛋白酶加酶量0.03%,pH8.0,水解温度50℃,时间7h。酶解液再经过凝胶层析分离纯化后可用于制备高F值寡肽。     

酶法提取金乌贼墨汁中黑色素的工艺条件研究

以金乌贼墨汁为原料,采用单因素试验,对胰蛋白酶,木瓜蛋白酶,胃蛋白酶,中性蛋白酶和碱性蛋白酶等五种酶提取黑色素的效果进行比较分析,筛选出水解效果较好的碱性蛋白酶。并通过正交试验,优化了碱性蛋白酶酶解金乌贼墨汁的最佳工艺,实验结果表明,在底物浓度2%、水解温度50℃、pH值为7.4,加酶量4200U/g和水解8h的条件下进行水解的效果较好。     

超高压酶解酪蛋白及其产物在动物细胞培养中的应用

以牦牛酪蛋白为底物,游离氨基酸含量为指标,在超高压条件下分别采用胰蛋白酶、胃蛋白酶、木瓜蛋白酶、中性蛋白酶、碱性蛋白酶和胰酶六种不同的酶水解酪蛋白并筛选出最佳用酶,并在单因素实验的基础上采用正交实验确定最佳用酶水解酪蛋白的最佳工艺条件。最后探讨水解产物在细胞培养中的应用。结果表明,胰酶水解效果最好,用其在底物浓度15%,E/S=1∶5、水解压力150 MPa,温度为45℃,pH 7.5条件下水解4h后水解产物中游离氨基酸含量高达52.18%。酶解产物对BHK-21细胞没有细胞毒性,而具有促生长作用。这为酪蛋白的进一步开发利用和蛋白质水解产物在细胞培养中的应用奠定基础。     

几种蛋白酶对文蛤肉的酶解工艺条件研究

以文蛤为原料,水解度为指标,从胰蛋白酶,木瓜蛋白酶,胃蛋白酶和风味蛋白酶中选出水解效果较好的胰蛋白酶和木瓜蛋白酶.并通过实验确定了胰蛋白酶,木瓜蛋白酶单酶水解及两者组合复合酶解文蛤肉的最佳工艺.结果表明:复合水解效果最佳.最佳工艺:先添加胰酶6000 u/g(原料),水解温度50℃,固液比1:3(V/W),pH 8.0,在此条件下水解6 h;然后改变条件,温度55℃,pH 5.5,底物浓度1:3(V/W),添加木瓜蛋白酶2000 u/g(原料),在此条件下水解2 h.通过实验验证,胰蛋白酶和木瓜蛋白酶组合在该条件下对文蛤肉蛋白具有较好的水解效果,其水解度为28.15%.     

Alcalase碱性蛋白酶对中华稻蝗蛋白水解条件的研究

本试验采用Alcalase碱性蛋白酶对中华稻蝗蛋白进行水解,研究其蛋白酶解条件和酶解物的抗氧化性(用抑制邻苯三酚自氧化率来表示).结果表明,实验室最佳酶解条件为:底物浓度1%,pH值8.0,温度55℃,水解时间4 h,加酶量(V/V,%)为10%.在此条件下其酶解物具有明显的抗氧化活性,对邻苯三酚自氧化的抑制率可达40%,水解度为51%.     

曼氏无针乌贼墨汁黑色素的提取工艺研究

曼氏无针乌贼墨汁的主要成分是黑色素、蛋白质及灰分。使用酶解法去除杂质,获得高纯度墨汁黑色素。通过对碱性蛋白酶、中性蛋白酶、酸性蛋白酶、胃蛋白酶、木瓜蛋白酶、胰蛋白酶的水解效果进行比较,挑选出水解效果最好的蛋白酶。通过单因素实验,比较不同p H值、温度、加酶量、水解时间,对黑色素提取的影响。在单因素实验的基础上,通过正交试验优化黑色素的提取工艺。实验结果表明,高纯度的黑色素可以用1.5%碱性蛋白酶在温度为50℃,p H值10.5和底物浓度为2%的条件下酶解4 h获得。     

牦牛骨蛋白的酶解条件研究

以蛋白质水解度为评价指标,辅以固形物溶出率,比较了中性蛋白酶、菠萝蛋白酶和木瓜蛋白酶对牦牛骨蛋白的水解效果,研究了酶用量、料液比(底物浓度)、酶解时间对水解度的影响,采用正交试验对酶解条件进行了优化。结果显示,木瓜蛋白酶是牦牛骨蛋白水解的适宜催化剂。在一定条件下,样品水解度随酶用量和酶解时间的增加而增大,底物浓度过低或过高均不利于原料中蛋白质的酶解。木瓜蛋白酶水解牦牛骨蛋白最佳条件为:酶解温度60℃,酶解时间8 h,酶用量3500 U/g蛋白质,料液比1:25(g:m l)。     

高温瞬时α化大米中可酶促水解α氨基氮含量的测定

经单因素和正交实验优化,高温瞬时α化大米的蛋白质酶促水解条件为:pH3.0,温度30℃,液固质量比为15,水解时间3 h,加酶量为2.0SAPU.g-1米粉。在该水解条件下测定不同处理条件下大米的酶促水解α氨基氮含量,揭示了其在高温瞬时α化过程中的变化规律,在一定程度上可用于指导生产。     

扇贝边蛋白资源酶法水解条件的优化

以扇贝边为原料,首先分析了其营养成分,结果表明,扇贝边干物质中蛋白质的含量为67.6%。然后用ASI,398枯草杆菌中性蛋白酶通过液体发酵对扇贝边蛋白资源进行了酶解条件优化,实验了酶解温度、酶的用量、酶水解时间和底物浓度等4因素对酶解效率的影响,确定了扇贝边的最佳水解条件:即酶解温度为50℃,蛋白酶的加入量为0.5%,即250U·ml^-1,底物浓度为6%,酶解时间为3h。     

双酶法制备螺旋藻多肽的工艺研究

选用碱性蛋白酶和木瓜蛋白酶结合的双酶法对螺旋藻蛋白进行水解。其中,对木瓜蛋白酶水解螺旋藻蛋白的工艺进行优化。以水解度为指标,研究了酶解时间、酶与底物比、pH和酶解温度4种因素对酶解反应的影响。在此基础上设计了3因素(加酶量、酶解温度和pH)3水平的响应面试验。结果表明碱性蛋白酶水解螺旋藻蛋白的最佳酶解条件为:加酶量4300 U/g,pH 7.0,酶解温度55℃,酶解时间160 min;木瓜蛋白酶的最佳酶解条件为:酶底比为4.5%,酶解温度60℃,pH 6.5,酶解时间210 min。利用碱性蛋白酶和木瓜蛋白酶结合的双酶法制得的多肽水解度可达32.90%,与单酶法相比,水解度明显提高。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.