STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS : II. ON DILUTE SOLUTIONS OF PROTEINS FROM EMBRYONIC AND OTHER TISSUES

1. An extensive investigation has been made of protein particle shape using the methods of flow-birefringence and anomalous viscosity measurement in the coaxial cell. 2. As a result of investigations on a number of proteins, it is concluded that they may be divided into four groups. Group A consists of those which show flow-anomaly both in the bulk phase and in the surface film. These also show flow-birefringence in the bulk phase. Examples: tobacco mosaic disease virus nucleoprotein; myosin. Though corpuscular proteins, they have elongated particles before denaturation. Group B consists of those which show flow-anomaly only (in the first instance) in the surface film, and no flow-birefringence in the bulk phase. They are probably close to spherical in shape in solution, but form elongated particles as they denature in the surface film. After this process has been completed, they may show flow-anomaly also in the bulk phase. Some proteins show flow-anomaly in the surface film immediately it forms, others only show it after a certain time has elapsed for the building up of the film. We designate the former as group B₁ and the latter as group B₂. Group B₁, immediate surface film flow-anomaly. Examples: serum euglobulin, amphibian embryo euglobulin b. Group B₂, slowly appearing surface film flow-anomaly. After the film has once been fully formed and then dispersed by shaking, the solution may have the properties of that of a protein in group B₁; i.e., anomalous flow in the film may occur immediately on testing in the viscosimeter. Examples: avian ovalbumin, amphibian embryo pseudoglobulin. Group C consists of those proteins which show flow-anomaly neither in the bulk phase nor in the surface film, under the conditions used by us. They are probably close to spherical in shape. Examples: insulin, methaemoglobin, amphibian embryo euglobulin c, mucoproteins. 3. The theoretical significance of protein fibre molecules, whether native or formed by denaturation in the living cell, is discussed, especially in relation to experimental morphology and cytology.     

STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS : I. GENERAL BEHAVIOUR OF PROTEINS SUBJECTED TO SHEAR

1. A coaxial viscosimeter which permits the simultaneous determination of relative and anomalous viscosity and of flow-birefringence is described. Flow-anomaly and flow-birefringence are regarded as characteristic of elongated micelles and molecules. 2. Such methods have been applied to dilute solutions of proteins. The conditions under which the coaxial (Couette) viscosimeter measures the viscosity of the bulk phase and the surface film phase respectively have been investigated and are described. 3. The general behaviour of protein solutions subjected to shear is summarised.     

STUDIES ON THE ANOMALOUS VISCOSITY AND FLOW-BIREFRINGENCE OF PROTEIN SOLUTIONS : III. CHANGES IN THESE PROPERTIES OF MYOSIN SOLUTIONS IN RELATION TO ADENOSINETRIPHOSPHATE AND MUSCULAR CONTRACTION

1. An investigation of the physicochemical properties of myosin has been carried out. Prepared under standard conditions, the ratio of flow-birefringence to protein concentration is uniform. The effect of electrolytes, pH, and urea on the flow-birefringence and viscosity (relative and anomalous) of myosin has been examined. 2. Decrease or abolition of flow-birefringence does not necessarily imply far reaching denaturation, since such effects can be reversed by a variety of means. 3. When a myosin solution is treated with adenosinetriphosphate, its flow-birefringence is decreased (average 48 per cent), its anomalous viscosity is retained, and its relative viscosity is decreased (average 14 per cent). The full effect of adenosinetriphosphate is obtained at 0.004 M; a molarity very much less than that of other substances which decrease the flow-birefringence of myosin. 4. The changes in the physicochemical properties of myosin brought about by adenosinetriphosphate are spontaneously reversible, and are connected with the enzymatic action of the protein as adenosinetriphosphatase. 5. Effects similar to those of adenosinetriphosphate on the physicochemical properties of purified myosin have been obtained so far only with inosinetriphosphate. 6. Inorganic phosphate is split off by myosin from inosinetriphosphate as well as from adenosinetriphosphate. Inorganic triphosphate is split by 1 to 2 per cent solution of three times precipitated myosin. 7. Adenosinediphosphate and inorganic triphosphate act as competitive inhibitors with adenosinetriphosphate, blocking the fall of flow-birefringence. 8. The implications of the results, and the conception of active enzymic groups attached to proteins participating in cell structure, whether contractile or non-contractile, are discussed in relation to present views on muscle physiology and other biological problems.     

DONNAN EQUILIBRIUM AND THE PHYSICAL PROPERTIES OF PROTEINS : III. VISCOSITY.

1. Gelatin solutions have a high viscosity which in the case of freshly prepared solutions varies under the influence of the hydrogen ion concentration in a similar way as the swelling, the osmotic pressure, and the electromotive forces. Solutions of crystalline egg albumin have under the same conditions a comparatively low viscosity which is practically independent of the pH (above 1.0). This difference in the viscosities of solutions of the two proteins seems to be connected with the fact that solutions of gelatin have a tendency to set to a Jelly while solutions of crystalline egg albumin show no such tendency at low temperature and pH above 1.0. 2. The formulæ for viscosity demand that the difference in the order of magnitude of the viscosity of the two proteins should correspond to a difference in the relative volume occupied by equal masses of the two proteins in the same volume of solution. It is generally assumed that these variations of volume of dissolved proteins are due to the hydration of the isolated protein ions, but if this view were correct the influence of pH on viscosity should be the same in the case of solutions of gelatin, of amino-acids, and of crystalline egg albumin, which, however, is not true. 3. Suspensions of powdered gelatin in water were prepared and it was found, first, that the viscosity of these suspensions is a little higher than that of gelatin solutions of the same concentration, second, that the pH influences the viscosity of these suspensions similarly as the viscosity of freshly prepared gelatin solutions, and third, that the volume occupied by the gelatin in the suspension varies similarly as the viscosity which agrees with the theories of viscosity. It is shown that this influence of the pH on the volume occupied by the gelatin granules in suspension is due to the existence of a Donnan equilibrium between the granules and the surrounding solution.     

POLLINATION SYSTEMS OF SYMPATRIC IPOMOEA HEDERACEA AND I. PURPUREA AND THE SIGNIFICANCE OF INTERSPECIFIC POLLEN FLOW

Mathematical models estimated that xenogamy accounted for 7% and 35% of the stigmatic pollen loads of Ipomoea hederacea and I. purpurea, respectively, in experimental populations. The xenogamy estimate for I. hederacea agreed closely with outcrossing estimates previously reported for this species. The discrepancy between the xenogamy estimate and the previously reported outcrossing estimate for I. purpurea could be explained by differing pollinator flight patterns between experimental and natural populations and/or by selection for cross pollen in the pistil of I. purpurea. Interspecific pollen flow from I. purpurea to emasculated flowers of I. hederacea reduced seed production in the latter. The possible significance of interspecific pollen flow from I. purpurea for the evolution of autogamy in I. hederacea was discussed.     

PHYSICOCHEMICAL PROPERTIES OF THE PROTEOLYTIC ENZYME FROM THE LATEX OF THE MILKWEED,ASCLEPIAS SPECIOSA TORR. SOME COMPARISONS WITH OTHER PROTEASES : I. CHEMICAL PROPERTIES,ACTIVATION-INHIBITION,pH-ACTIVITY,AND TEMPERATURE-ACTIVITY CURVES

1. A study has been made of the properties of a hitherto unreported proteolytic enzyme from the latex of the milkweed, Asclepias speciosa. The new protease has been named asclepain by the authors. 2. The results of chemical, diffusion, and denaturation tests indicate that asclepain is a protein. 3. Like papain, asclepain dots milk and digests most proteins, particularly if they are dissolved in concentrated urea solution. Unlike papain, asclepain did not clot blood. 4. The activation and inhibition phenomena of asclepain resemble those of papain, and seem best explained on the assumption that free sulfhydryl in the enzyme is necessary for proteolytic activity. The sulfhydryl of asclepain appears more labile than that of papain. 5. The measurement of pH-activity curves of asclepain on casein, ovalbumin, hemoglobin, edestin, and ovovitellin showed no definite digestion maxima for most of the undenatured proteins, while in urea solution there were well defined maxima near pH 7.0. Native hemoglobin and ovovitellin were especially undigestible, while native casein was rapidly attacked. 6. Temperature-activity curves were determined for asclepain on hemoglobin, casein, and milk solutions. The optimum temperature was shown to increase with decreasing time of digestion.     

中华眼镜蛇蛇毒因子(CVF)对补体系统的作用及与人补作C_3和其他蛇毒抗原性关系

中华眼镜蛇蛇毒经DEAE-Sepharose CL-6B。HPLC等多次柱层析分离出有抗补体及溶血活性的眼镜蛇蛇毒因子(Cobra venom factor,CVF),纯化后的CVF在聚丙烯酰胺凝胶电泳图谱上呈单一区带,分子量为225000—230000,等电点为6.20。用二硫苏糖醇还原经SDS-聚丙烯酰胺凝胶电泳得三类亚基,其分子量总和为237,000。 体外抗补体及溶血试验表明,CVF的作用是通过补体旁路途经使总补体活力下降。双向免疫电泳鉴定,发现CVF与人血清作用后,其中补体成分C_3分子的抗原性发生改变,则表明CVF的作用是通过激活补体成分C_3而发挥的。给豚鼠腹腔注射CVF(0.15ug/g体重)后,其血清总补体水平下降到正常值的3％以下,7天后回升,13天后恢复到正常水平。 单相免疫电泳表明,CVF与人补体C_3抗血清间无任何交叉免疫反应,但人血清与CVF抗血清间有微弱的免疫沉淀反应。另外,CVF的氨基酸组成与人补体C_3也较为相似。鉴定还表明眼镜蛇科中四种蛇毒与CVF抗血清有强烈的免疫沉淀反应,蝰蛇毒及海蛇毒也有免疫沉淀反应,但只有眼镜蛇毒具有抗补体活性。     

NOVEL WAY OF CAPPING mRNA TRIMER AND STUDIES OF ITS INTERACTION WITH HUMAN NUCLEAR CAP-BINDING COMPLEX

Binding of mRNA 5′ cap by the nuclear cap-binding complex (CBC) is crucial for a wide variety of mRNA metabolic events. The interaction involving the CBP20 subunit of CBC is mediated by numerous hydrogen bonds and by stacking of the tyrosine sidechains with two first bases of the capped mRNA. To examine a possible role of a longer mRNA chain in the CBC-cap recognition, we have synthesized an mRNA tetramer using a novel way of capping an RNA trimer and determined its affinity for CBC by fluorescence titration.     

应用探针及影印技术分离产2—KGA蛭弧菌及其生物学特性

应用SMA探针技术,以及HB－HG影印技术,从103个样品中分离出三林产2－KGA的蛭弧菌J26、91－2、91－4,通过对J26初步发酵实验表明：J26经10批次发酵平均产2－KGA达到50－60mg／ml。另外,对J26主要生物学特性进行了研究,尤其对J26作为蛭弧菌的主要特性──浸染性进行了研究,证实了J26是一株具有侵入宿主生长周期和不依赖宿主生长周期两种生长繁殖模式的兼性蛭弧菌。     

利用硬皮病病人的自发抗体研究着丝点抗原的保守性及其性质

本文分别用四种CREST综合症硬皮病病人自发抗着丝点血清,对六种类型的细胞进行了间接免疫荧光染色。染色结果表明:这种着丝点抗原在进化中保持了高度的保守性,它在哺乳类、爬行类、两栖类、鱼类、无脊椎动物昆虫纲甚至植物细胞中都具有相似的抗原性。另外,本文对这种着丝点抗原的性质也进行了研究,细胞化学分析表明:人喉癌细胞Hep-2和中华大蟾蜍骨髓细胞内的这种着丝点抗原,它们具有完全相似的抗原性质,均为紧密结合的非组蛋白。本文中所用的实验方法在临床上可直接应用于抗着丝点抗体的检测,因此,具有一定的实践意义。     

STUDIES ON SYSTEMIC FUNGICIDES. I. FUNGICIDAL PROPERTIES OF THE ARYLOXYALKYLCARBOXYLIC ACIDS

A method is described for assessing the systemic activity of compounds in checking the infection of broad bean ( Vicia faba ) by the fungi Botrytis cinerea or B. fabae. Treatment consisted in allowing the roots of young seedlings to stand in a solution containing 10 p.p.m. of the chemical for 2–3 weeks. The plants, together with controls, were then inoculated and when symptoms had had time to develop, the degree of chocolate spot infection was assessed. Several methods of disease assessment were examined and are critically discussed.
Certain phenoxyalkylcarboxylic acids tested by this method consistently gave a reduction in the mean size of fungus lesions on the bean leaves, clearly indicating systemic fungicidal action. The most promising substances were 2:4:6-trichlorophenoxyacetic, pentachlorophenoxyacetic and pentachlorophenoxy iso butyric acids. Further experiments with these compounds involving soil treatment, stem injection and spray application are described, and in most cases systemic fungicidal activity was clearly demonstrated. Certain compounds caused visible damage to the plants or resulted in a reduction in growth.
The results presented indicate that phenoxy acids can be fairly readily translocated in bean plants and that they tend to accumulate in actively growing tissues. It is considered unlikely, however, that they persist for long periods in plant tissue.
In the soil, the compounds appeared to remain effective for a considerable time, particularly the less soluble pentachloro acids, suggesting that soil application might provide a safe and useful method of treatment.     

STUDIES ON BLOOD COAGULATION : II. THE FORMATION OF FIBRIN FROM THROMBIN AND FIBRINOGEN

Although calcium is essential for the formation of thrombin, it can be recovered quantitatively from formed horse thrombin without affecting its coagulating activity. Citrate also has no significant effect. As stated in the text, this does not exclude the possibility that thrombin is actually a calcium compound present in minute concentration; but confirming the results of Hammarsten, it does show that fibrin cannot be a calcium-protein compound unless one assumes molecular weights for fibrinogen greater than 1,000,000. Although the available experimental data concerning the properties of thrombin, the kinetics of its reaction with fibrinogen, and the quantitative relationships between the two do not allow a definite decision as to whether thrombin is an enzyme analogous to rennin, or whether it combines with fibrinogen to form an insoluble compound, fibrin, the weight of evidence does favor the enzyme theory. A given quantity of thrombin can form at least 200 times its weight of fibrin, and in view of the crudeness of the preparation this ratio is probably many times greater. There is no apparent stoichiometric relationship between thrombin and fibrinogen, and thrombin does not disappear from a mixture of the two until the moment of coagulation; the quantity which then disappears is many times the minimal quantity necessary to form the amount of fibrin produced.     

STUDIES OF GAS AND ELECTROLYTE EQUILIBRIA IN THE BLOOD : IX. THE DISTRIBUTION OF ELECTROLYTES BETWEEN TRANSUDATES AND SERUM.

1. Analyses have been made of the electrolytes and proteins of serum and transudates from human subjects. 2. The distribution ratios of HCO₃, Cl, Na, and H⁺ deviated from unity as predicted by the Gibbs-Donnan law for similar heterogeneous systems. 3. Analyses of serum, and of artificial salt solutions approximating edema fluid in composition, after equilibration across collodion membranes showed distributions similar to those between serum and edema fluid in vivo.