用猪血生产混合氨基酸工艺中水解时间的研究

<正> 用蛋白质水解法生产混合氨基酸,水解时间是一个至关重要的问题。水解时间太短,水解不完全,含肽量高,水解时间过长,会引起许多氨基酸酌破坏,即降低了得率又浪费了能源。我们在用阴离子交换树脂法脱酸法,以猪血为源料生产混合氨基酸工艺扩大试验时,对干猪血块的水解时间与水解程度的关系透行了探索,实验的结果列于下表:     

The Destruction of Cytoplasmic Basophilia with Mineral Acids

Cytoplasmic basophilia may be selectively destroyed by the mineral acids, HNO₃, HCl and H₂SO₄. Their specificity is similar to that of ribonuclease. The optimal conditions for their use are 3°C. for 16 hours at 2M concentrations. Removal of cytoplasmic basophilia as with ribonuclease, malt diastase and perchloric acid is most effective on sections prepared from tissues fixed in solutions containing no chromates. Under the conditions herein reported the mineral acids appear to be a satisfactory and economical substitute for ribonuclease or perchloric acid.     

Antimicrobial Activity of 8-Quinolinols, Salicylic Acids, Hydroxynaphthoic Acids, and Salts of Selected Quinolinols with Selected Hydroxy-Acids

Seventy-seven compounds were screened by the disc-plate method against strains of five bacteria and five fungi. A new constant was proposed to describe the antimicrobial activity of a compound in a defined system of organisms. This constant includes not only the inhibitory level of activity of the material but also the number of organisms inhibited. This constant, the antimicrobial spectrum index, was compared with the antimicrobial index of Albert.     

Metabolism of Arachidonic Acid to Epoxyeicosatrienoic Acids. Hydroxyeicosatetraenoic Acids, and Prostaglandins in Cultured Rat Hippocampal Astrocytes

Abstract: We have recently shown that brain slices are capable of metabolizing arachidonic acid by the epoxy-genase pathway. The purpose of this study was to begin to determine the ability of individual brain cell types to form epoxygenase metabolites. We have examined the astrocyte epoxygenase pathway and have also confirmed metabolism by the cyclooxygenase and lipoxygenase enzyme systems. Cultured rat hippocampal astrocyte homogenate, when incubated with radiolabeled [³H]-arachidonic acid, formed products that eluted in four major groups designated as R_17–30, R_42–50, R_51–82, and R_83–90 based on their retention times in reverse-phase HPLC. These fractions were further segregated into as many as 13 peaks by normal-phase HPLC and a second reverse-phase HPLC system. The principal components in each peak were structurally characterized by gas chromatography/electron impact-mass spectrometry. Based on HPLC retention times and gas chromatography/electron impactmass spectrometry analysis, the more polar fractions (R_17–30) contained prostaglandin D₂ as the major cyclooxygenase product. Minor products included 6-keto prostaglandin F_1α, prostaglandin E₂, prostaglandin F_2α, and thromboxane B₂. Fractions R_42–50, R_51–82. and R_83–90 contained epoxygenase and lipoxygenase-like products. The major metabolite in fractions R_83–90 was 5, 6-epoxyeicosatrienoic acid (EET). Fractions R_51–82 contained 14, 15-and 8, 9-EETs, 12-and 5-hydroxyeicosatetraenoic acids, and 8, 9-and 5, 6-dihydroxyeicosatrienoic acids (DHETs). In fractions R_42–50, 14, 15-DHET was the major product. When radiolabeled [³H]14, 15-EET was incubated with astrocyte homogenate, it was rapidly metabolized to [³H]14, 15-DHET. The metabolism was inhibited by submicromolar concentration of 4-phenylchalcone oxide, a potent inhibitor of epoxide hydrolase activity. Formation of other polar metabolites such as triols or epoxyalcohols from 14, 15-DHET was not observed. In conclusion, astro-cytes readily metabolize arachidonic acid to 14, 15-EET, 5, 6-EET, and their vicinal-diols. Previous studies suggest these products may affect neuronal function and cerebral blood flow.     

Compartmentation of Organic Acids in Corn Roots. III. Utilization of Exogenously Supplied Acids

The rates of utilization of exogenously supplied ¹⁴C labeled acids by corn roots was compared to the utilization of these acids generated endogenously in the mitochondria from acetate-³H. ¹⁴C-labeled citrate, pyruvate, succinate, glutamate or aspartate were supplied with acetate-³H in a 15 minute pulse and the ¹⁴C and ³H contents of extracted acids were measured over a 4 hour period. It was found, in contrast to previous experiments with malate, that these exogenously added acids were used as rapidly as the endogenous forms. Apparently, therefore, these acids penetrate readily into the mitochondria and do not enter cytoplasmic pools which are not in ready equilibrium with those in the mitochondria. Small amounts of labeled glutamate were produced from succinate-2,3-³H by corn root tissue. Since glutamate would not be expected to be labeled by reactions of the tricarboxylic acid cycle it was concluded that it was produced rather directly from succinate. The minor pool of glutamate generated in this way retained its radioactivity while that generated in the cycle was rapidly lost. An extra-mitochondrial location of this pool of glutamate is therefore suggested.     

Qualitative Identification of Carboxylic Acids,Boronic Acids,and Amines Using Cruciform Fluorophores

Molecular cruciforms are X-shaped systems in which two conjugation axes intersect at a central core. If one axis of these molecules is substituted with electron-donors, and the other with electron-acceptors, cruciforms'' HOMO will localize along the electron-rich and LUMO along the electron-poor axis. This spatial isolation of cruciforms'' frontier molecular orbitals (FMOs) is essential to their use as sensors, since analyte binding to the cruciform invariably changes its HOMO-LUMO gap and the associated optical properties. Using this principle, Bunz and Miljanić groups developed 1,4-distyryl-2,5-bis(arylethynyl)benzene and benzobisoxazole cruciforms, respectively, which act as fluorescent sensors for metal ions, carboxylic acids, boronic acids, phenols, amines, and anions. The emission colors observed when these cruciform are mixed with analytes are highly sensitive to the details of analyte''s structure and - because of cruciforms'' charge-separated excited states - to the solvent in which emission is observed. Structurally closely related species can be qualitatively distinguished within several analyte classes: (a) carboxylic acids; (b) boronic acids, and (c) metals. Using a hybrid sensing system composed from benzobisoxazole cruciforms and boronic acid additives, we were also able to discern among structurally similar: (d) small organic and inorganic anions, (e) amines, and (f) phenols. The method used for this qualitative distinction is exceedingly simple. Dilute solutions (typically 10^-6 M) of cruciforms in several off-the-shelf solvents are placed in UV/Vis vials. Then, analytes of interest are added, either directly as solids or in concentrated solution. Fluorescence changes occur virtually instantaneously and can be recorded through standard digital photography using a semi-professional digital camera in a dark room. With minimal graphic manipulation, representative cut-outs of emission color photographs can be arranged into panels which permit quick naked-eye distinction among analytes. For quantification purposes, Red/Green/Blue values can be extracted from these photographs and the obtained numeric data can be statistically processed.     

Accq.Tag法测定氨基酸口服液的氨基酸含量

采用AccQ .Tag法对氨基酸口服液中游离氨基酸和牛磺酸含量进行了分离测定。产品中氨基酸总量达 85mg/ml以上 ,共 1 3种氨基酸。必需氨基酸与非必需氨基酸比例为 2 .2 0～ 2 .50∶1 ,支 /芳比为 2 .30～ 2 .55∶1 .配方接近于FAO氨基酸比例模式 ,以FAO氨基酸模式及化学评分评价了该制剂的营养价值 ,基本上不存在限制氨基酸 ,化学评分均在 90分以上。     

The Production of Organic Acids

Abstract

The production of organic acids covers two aspects: first, the metabolic pathways involved in the biosynthesis, and, second, the industrial process strategy adopted. The review seeks to show the underlying biochemical similarities in the biosynthesis of organic acids and the resulting similarities in the commercial processes.

Two groups of acids are defined, those with a “long” biosynthetic path from glucose, involving much of the glycolytic pathway and the tricarboxylic acid cycle, and those acids with a “short pathway”, essentially a biotransformation of glucose. The regulation of the pathways and the future developments in metabolic control theory and genetic manipulations relating to them are considered. The organisms used industrially are also limited, Aspergillus sp. and Candida yeasts; again the underlying metabolic similarities lead to similar strategies for all the acids discussed.     

The Chemistry of Areneboronic Acids

Benzeneboric acid causes a marked increase in the endogenous fermentation of pressed baker's yeast. It is shown that an increased leakage of trehalose occurs and it is suggested that benzeneboronic acid affects the permeability of the cytoplasmic membranes.     

The Flexibility of the Nucleic Acids: (III) The Interaction of an Aliphatic Diamine,Putrescine, with Flexible B-DNA

Abstract

A theoretical modelling of the interaction of putrescine (H⁺ ₃N—(CH₂)₄—(-N⁺H₃) with DNA is carried out, introducing two new features which make the simulation of this interaction considerably more realistic. Firstly, the DNA to which putrescine is bound is fully flexible and thus able to respond to the distorting influence of the ligand. Secondly, the effect of changing the ratio of DNA base pairs per bound ligand is explicitly modelled. In this way. we have been able to confirm the experimentally known preference of putrescine binding with AT base pairs in B-DNA, but we also show, through the new features introduced, that the nature of the binding site of the ligand and the resulting impact on DNA conformation is strongly modified by the ligand binding density.     

Sugar Level, Fermentability, and Acceptability of Straw Treated with Different Acids

The sugar level, fermentability, and acceptability by voles of ryegrass straw treated with different acids were compared. Sugar release was highest with HCl, but acceptability was best with H₃PO₄ treatment. Candida utilis grew about equally well on all of the treated samples, except the one treated with 0.5 N HCl. That sample supported no growth, possibly because the level of chloride or degradation products of monomeric sugars was too high. Fermentability and palatability of straw were highest when treated with a combination of 0.23 N HCl and 0.15 N H₃PO₄. Fermentation with Aureobasidium pullulans further increased the palatability of the acid-treated straw.     

血液杆菌Haem atobacter sp.细胞脂肪酸测定的影响因素

应用美国MIDI公司Sherlock MIS系统检测一株归属于血液杆菌属的新菌种Haematobacter sp.HNMC11807的细胞脂肪酸组成,探讨不同培养方法和条件对其细胞脂肪酸组成的影响。采用不同培养条件培养微生物细胞,即不同的培养基组成、固液类型和培养时间;分析比较细胞脂肪酸检测结果存在的差异。同时对比分析仪器专用的两种检测体系,即常规标准和快速标准体系,对样品脂肪酸测定结果的影响。结果发现,细胞脂肪酸组成与其培养条件密切相关,且差异显著。因此,在应用该系统做微生物分类鉴定时,必需严格遵守特定的、统一的培养条件平行进行。     

复合氨基酸治疗眼角膜溃疡的研究

复合氨基酸在临床上的应用越来越被人们重视,我们利用水解猪血粉的方法得到含１７种氨基酸的复合液,配制成滴眼剂用于多种原因引起的眼角膜溃疡疾病的治疗研究取得了较好的效果。