温度对兰州鲇消化酶活性的影响

测定了兰州鲇(Silurus lanzhouensis)胃、肝胰脏、前肠、中肠、后肠在不同温度(15℃、20℃、25℃、30℃、37℃4、2℃、47℃)条件下的蛋白酶、淀粉酶和脂肪酶的活性。结果表明,随温度的升高,各种酶活性的变化均表现为先增高后下降直至不能检出。消化道各部位蛋白酶的最适温度均为42℃;淀粉酶的最适温度除胃和肝胰脏为37℃外,其他部位均为30℃;脂肪酶的最适温度除后肠为30℃外,其他部位均为25℃。消化酶的最适温度高于其生活水域的水温,反映出消化酶作为酶蛋白的耐热性。最适温度下,蛋白酶活性前肠≈中肠>后肠>肝胰脏≈胃;淀粉酶活性前肠>中肠>肝胰脏>胃>后肠;脂肪酶活性中肠>后肠>前肠≈肝胰脏>胃。研究结果还表明,前肠和中肠是兰州鲇消化蛋白的主要部位,中肠是其消化脂肪的主要部位,而前肠是其消化淀粉的主要部位。在消化酶表现出活性的温度范围内,蛋白酶活性明显高于淀粉酶活性。实验还表明脂肪酶具有活性的温度范围较蛋白酶和淀粉酶窄。     

温度和pH对洞庭鲇鱼消化酶活性的影响

采用酶学分析方法研究了温度和pH对洞庭鲇鱼蛋白酶、脂肪酶和淀粉酶活力的影响。结果表明,在设定的温度和pH范围内,鲇鱼各消化酶的活力均随着温度和pH的升高呈现先升后降的变化趋势。其中,胃蛋白酶的最适温度为40℃,肝胰脏、前肠、中肠和后肠蛋白酶的最适温度为45℃;脂肪酶的最适温度均为35℃;胃淀粉酶的最适温度为35℃,其他部位均为30℃。胃、肝胰脏、前肠、中肠和后肠蛋白酶的适宜pH分别为2.0、8.5、7.5、8.0和8.0;脂肪酶的适宜pH均为7.5;淀粉酶肝胰脏的适宜pH为7.5,其余部位均为7.0。鲇鱼各消化酶活力存在器官特异性。在最适温度下,蛋白酶活力顺序为前肠>肝胰脏>胃>中肠>后肠,脂肪酶的活力顺序均为肝胰脏>胃>前肠>中肠>后肠,淀粉酶的活力顺序为肝胰脏>前肠>中肠>后肠>胃,各部位之间差异显著(P<0.05)。     

温度和pH对白斑狗鱼消化酶活性的影响

目的:通过改变酶的反应温度和pH,离体分析白斑狗鱼体内淀粉酶、蛋白酶和脂肪酶活性变化.方法:分别采用Folin酚法、DNS法和氢氧化钠滴定法测定蛋白酶、淀粉酶和脂肪酶活性.结果:在白斑狗鱼肝胰脏、胃二部位,淀粉酶的最适温度均为30℃,肠道淀粉酶的最适温度为40℃;最适pH值分别为4.0、2.0、7.0.肝胰脏、胃二部位脂肪酶的最适温度均为40℃,肠道脂肪晦的最适温度为50℃;最适pH值分别为5.0,4.0、5.0.肝胰脏、胃、肠道蛋白酶的最适温度均为50℃;最适pH值分别3.0、3.0、9.0.结论:在各自最适温度下,脂肪酶、淀粉酶、蛋白酶比活力均为:肠道＞胃＞肝胰脏.     

牛蛙主要消化酶的分布及pH和温度对消化酶活力的影响

研究了牛蛙消化系统蛋白酶、脂肪酶、淀粉酶和纤维素酶的分布情况以及pH和温度对这些消化酶活力的影响.结果表明:在各自生理pH值下,牛蛙消化系统不同部位蛋白酶活力大小顺序依次为胰脏>胃>中肠>食道>前肠>后肠,胃、肠和胰脏蛋白酶的最适pH值分别为2.2、7.4和9.6,最适温度分别为45℃、50℃和45℃.脂肪酶活力大小顺序依次为胰脏>后肠>中肠>前肠>胃>食道,胃、肠和胰脏脂肪酶的最适pH值分别为2.2、7.4和8.0,最适温度均为50℃.淀粉酶活力大小顺序依次为胰脏>中肠>后肠>前肠>胃>食道,胃、肠道和胰脏淀粉酶的最适pH分别为7.0、8.0和9.6,最适温度均为35℃.在牛蛙消化系统未检测到明显纤维素酶活力.     

虎纹蛙消化道淀粉酶和脂肪酶活力研究

以酶学分析方法研究了虎纹蛙消化道淀粉酶和脂肪酶的分布以及pH和温度对这两种消化酶活力的影响。结果表明：在各自生理pH值条件下,虎纹蛙消化道不同部位淀粉酶活力大小顺序依次为前肠〉中肠〉后肠〉食道〉胃,胃和肠淀粉酶最适pH值分别为8．6和7．0,最适温度分别为35℃和40℃。脂肪酶活力大小顺序依次为中肠〉后肠〉前肠〉胃〉食道,各部位之间差异显著（P〈0．05）,胃和肠脂肪酶的最适pH值均为9．0,最适温度分别为50℃和55℃。     

中华真地鳖中肠主要消化酶的活性研究

以中华真地鳖EupolyphagasinensisWalker为研究材料,测定人工饲养和野生地鳖虫在不同生长阶段消化酶的活性以及温度及pH对人工饲养地鳖虫中肠消化酶活性的影响。结果表明,在地鳖虫生长发育过程中,蛋白酶和脂肪酶活性随发育而逐渐增强,淀粉酶活性却随发育而逐渐减弱。在低龄若虫、高龄若虫和成虫阶段,人工饲养地鳖虫蛋白酶活力比野生地鳖虫低,人工饲养地鳖虫淀粉酶和脂肪酶活力比野生地鳖虫高;在30～60℃的范围内,人工饲养地鳖虫蛋白酶、淀粉酶的适宜温度范围为40～50℃,脂肪酶的适宜温度范围为35～45℃;蛋白酶、淀粉酶和脂肪酶的适宜pH范围分别为6.5～7.5,5.6～6.4和7.5～8.5。     

额尔齐斯河野生丁(鐬)蛋白酶、淀粉酶活性的研究

目的:研究温度、pH、金属离子对新疆额尔齐斯河野生丁(鐬)消化道蛋白酶、淀粉酶活性的影响.方法:酶学和生化法.结果:丁(鐬)蛋白酶活性,后肠＞前肠＞中肠＞肝胰脏;淀粉酶活性,后肠＞中肠＞前肠＞肝胰脏.肠道、肝胰脏蛋白酶的最适温度分别为35℃、40℃,淀粉酶的最适温度均为40℃.消化道各部位蛋白酶、淀粉酶的体外最适pH为7.5.在试验的离子浓度范围,高浓度Ag 、Cu2 抑制酶活力;高浓度Fe3 、Mg2 、Ca2 促进酶活力;Pb 、Ba2 对消化道酶活力影响依浓度和部位而变.结论:消化酶最适温度均高于所处环境温度,最适pH值变化范围偏碱性;不同浓度金属离子对丁(鐬)消化道各部位蛋白酶、淀粉酶活力高低表现出不同的变化趋势.     

pH值对中国龙虾消化酶活力的影响

采用酶学分析方法研究了pH对中国龙虾胃蛋白酶、类胰蛋白酶、淀粉酶、纤维素酶和脂肪酶活力的影响。结果表明,在设定的pH范围内,中国龙虾各消化酶的活力均随着pH的升高呈现先升后降的变化趋势。其中,胃、肠、肝胰腺内胃蛋白酶最适pH均为2.2,类胰蛋白酶最适pH分别为8.8-9.2、8.4、8.8,淀粉酶最适pH分别为7.0、7.0、7.4,纤维素酶最适pH分别为4.2、4.2-4.6、5.4,脂肪酶最适pH分别为7.2-7.6、7.2、6.8-7.2。同时测得中国龙虾胃、肠、肝胰腺内的生理pH分别为5.33、6.93、6.60。中国龙虾的消化酶活力存在器官特异性。在最适pH下,胃蛋白酶活力顺序为胃>肠>肝胰腺,类胰蛋白酶、纤维素酶、脂肪酶的活力顺序均为肝胰腺>肠>胃,淀粉酶的活力顺序为肠>肝胰腺>胃。     

云斑尖塘鳢消化酶活力的研究

本文采用酶学分析方法研究了云斑尖塘鳢在正常摄食状态与饥饿的状态下胃、肠及肝胰脏组织中蛋白酶、淀粉酶和脂肪酶的活性。结果显示,在30℃的条件下,正常摄食组样本在酸性条件下的蛋白酶活力表现为:胃后肠肝胰脏前肠,中性和碱性条件下:后肠肝胰脏前肠及胃;饥饿组样本仅有胃表现出较高的酸性蛋白酶活性,其他器官的蛋白酶活性均很低。在正常和饥饿实验组中肝胰脏的淀粉酶活性均高于其他器官,胃肠的淀粉酶活性均较低。正常摄食组中脂肪酶活力后肠肝胰脏;而在饥饿组中仅有肝胰脏检测到脂肪酶活性。结果表明,云斑尖塘鳢适度饥饿组较正常摄食组消化酶活性大幅降低;其高蛋白酶活力及中等脂肪酶活力与其肉食性相一致;此外云斑尖塘鳢也具备少量的淀粉消化能力。     

温度对南疆沙蜥和密点麻蜥消化酶活性的影响

为探究不同温度对南疆沙蜥Phrynocephalus forsythii和密点麻蜥Eremias multiocellata消化酶活性的影响,本研究测定了不同温度下南疆沙蜥和密点麻蜥的肝脏、胃及十二指肠的消化酶——淀粉酶(碘-淀粉比色法)、脂肪酶(比浊法)及胰蛋白酶(紫外线吸收法)的活性。结果显示,南疆沙蜥和密点麻蜥消化酶活性在4～45℃随着温度升高呈现先上升、后下降的趋势;40℃驯化的南疆沙蜥、35℃驯化的密点麻蜥肝脏、胃及十二指肠的淀粉酶、脂肪酶及胰蛋白酶活性最高。南疆沙蜥和密点麻蜥消化酶活性具有温度依赖性,这与机体在不同温度下的生理机能是密切相关的。同时,2种蜥蜴的消化酶活性最大时的驯化温度明显不同,这与它们偏好的环境温度密切相关。     

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.     

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.     

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.     

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.     

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。     

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.