蒸汽爆破处理沙柳原料酶解条件优化

研究蒸汽爆破预处理对沙柳原料酶解效果的影响,通过响应曲面实验设计法优化蒸汽爆破处理沙柳原料的酶解工艺。结果表明,蒸汽爆破预处理沙柳原料的最佳蒸汽爆破处理条件：压力3.5 MPa、维压时间300 s; 蒸汽爆破最佳酶解条件：pH 4.8、温度53.5 ℃、 每克底物酶加量29.8 FPU。在最优条件下,蒸汽爆破处理沙柳原料的酶解率可以达到最大值87.92%,并验证了数学模型的有效性,试验结果表明蒸汽爆破预处理可以有效提高沙柳原料的水解率。     

胃蛋白酶水解绿豆分离蛋白的工艺

选用胃蛋白酶对绿豆分离蛋白进行酶法水解,考察了原料预处理条件、pH、温度、底物浓度等对酶解的影响,结果表明：原料预处理最适条件为沸水浴中90℃处理20min,在37℃、pH1．8、底物质量分数7％、酶量6000U／g条件下酶解180min,水解度（DH％）为19．86％,达到了制备小肽的水解度要求。实验证明,经过水解,绿豆分离蛋白各功能特性得到很好的改善。     

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)。     

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。     

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%.     

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。     

海马总蛋白提取及其酶解条件优化

为了提取海马总蛋白并确定最佳的酶解条件,将海马粉碎后采用水提法提取海马总蛋白。分别选用木瓜蛋白酶、碱性蛋白酶、中性蛋白酶和胰蛋白酶,在不同酶解p H、时间、温度和E/S条件下进行单因素和正交试验法对海马总蛋白的酶解条件进行优化。利用聚丙烯酰胺凝胶电泳和BCA法来分别检测不同条件下的酶解情况及其蛋白含量,根据蛋白水解度来确定其最佳的酶解条件。实验结果表明:从10 g干海马中提取总蛋白为1.056 g,蛋白浓度为0.106 g/m L。海马总蛋白的最佳水解酶为碱性蛋白酶,其最佳酶解条件为:p H 9,E/S为5%,温度为50℃,时间为3 h,获得海马总蛋白的最大水解度为96.9%。研究获得了海马总蛋白及其最佳酶解条件,并为海马多肽生物活性研究奠定了基础。     

胃蛋白酶和木瓜蛋白酶水解核桃蛋白工艺研究

以核桃粕为原料,以水解度为考察指标,研究胃蛋白酶和木瓜蛋白酶对核桃蛋白的水解作用.结果表明：木瓜蛋白酶为酶解核桃蛋白最佳酶,其最佳酶解条件为底物浓度4％、酶质量分数5％、酶解 pH 值为7．0、酶解温度50℃、酶解时间4 h;在该条件下,木瓜蛋白酶酶解核桃蛋白水解度可高于25．76％.     

海参制备胶原蛋白肽工艺研究

主要研究以海参体壁为原料制备胶原蛋白肽的工艺条件,通过单因素和正交试验对酶解条件进行优化。结果表明,使用木瓜蛋白酶的酶解效果最好,最佳酶解条件为:酶解温度55℃、p H值7.0、加酶量2%、料液比1:30和提取时间3 h,此条件下海参胶原蛋白肽水解度达到14.23%。     

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%.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.