STABILITY OF SUSPENSIONS OF SOLID PARTICLES OF PROTEINS AND PROTECTIVE ACTION OF COLLOIDS

1. It is shown that the concentrations of different salts required to precipitate suspensions of gelatin-coated collodion particles in water are practically identical with the concentrations of the same salts required for the "salting out" of gelatin from aqueous solutions. Neither effect shows any relation to the electrical double layers surrounding the particles. 2. It is shown that at the isoelectric point of gelatin, suspensions of gelatin-coated collodion particles are not stable and it had been shown previously that gelatin is least soluble at the isoelectric point. The addition of salt increases both the solubility of gelatin in water as well as the stability of suspensions of gelatin-coated collodion particles in water, and both effects increase with the valency of one of the ions of the salt. 3. This latter effect is not due to any charges conferred on the gelatin particles by the salts, since the cataphoretic experiments show that salts like NaCl, Na₂SO₄, or CaCl₂, which at the isoelectric point of gelatin increase the solubility of gelatin as well as the stability of suspensions of gelatin-coated collodion particles, leave the particles practically uncharged in the concentrations in which the salts are efficient. 4. It follows from all these facts that the stability of suspensions of gelatin-coated particles in water depends on the solubility of gelatin in water; e.g., on the chemical affinity of certain groups of the gelatin molecule for water. 5. Though crystalline egg albumin is highly soluble in water, the stability of collodion particles coated with crystalline egg albumin does not depend upon the affinity of the albumin molecule for water, but depends practically alone on the electrical double layer surrounding each particle. As soon as the P.D. of this double layer falls below 13 millivolts, the suspension is no longer stable. 6. The critical potential for the stability of suspensions of collodion particles coated with genuine egg albumin is the same as that for particles of boiled (denatured) white of egg. Since through the process of heating, egg albumin loses its solubility in water, it is inferred that egg albumin undergoes the same change when it forms a film around a solid particle like collodion. 7. The influence of electrolytes on the stability of suspensions of collodion particles coated with casein or edestin was similar to that of collodion particles coated with egg albumin. The experiments are, however, complicated by the fact that near the isoelectric point CaCl₂ and even NaCl cause a suspension again at concentrations of about M/2 or 1 M, while still higher concentrations may cause a precipitation again. These latter effects have no connection with double layers, but belong probably in the category of solubility phenomena. 8. These experiments permit us to define more definitely the conditions for a general protective action of colloids. Protective colloids must be capable of forming a durable film on the surface of the suspended particles and the molecules constituting the film must have a higher attraction for the molecules of the solvent than for each other; in other words, they must possess true solubility. Only in this case can they prevent the precipitating action of low concentrations of electrolytes on particles which are kept in suspension solely by the high potentials of an electrical double layer. Thus gelatin films, in which the attraction of the molecules for water is preserved, have a general protective action, while crystalline egg albumin, casein, and edestin, which seem to lose their attraction for water when forming a film, have a protective action only under limited conditions stated in the paper.     

光照对蕨类植物配子体假根向重力性的影响

对８种蕨类植物配子体假根向重力性反应的研究结果表明,除卷柏Ｓｅｌａｇｉｎｅｌｌａ ｔａｍａｒｉｓｃｉｎａ Ｓｐｒｉｎｇ配子体假根无向重力性反应并且其生长方向与光照方向无关外,其它７种的配子体假根均有向重力性反应,并且假根的向重力性反应在配子体发育初期,因光照的方向不同而异,表现为负向光性。随着配子体发育至片状体阶段,光对其向重力性反应的影响逐渐减弱,而重力的影响增强。在蕨类植物配子体发育初期,光对     

黑莓鲜果及其加工品的营养成分

本文首次报道了黑莓引入南京后其果实和加工品的营养成分。结果表明:黑莓鲜果富含V_E,还含有较高的钾、锌、铁、硒等矿质元素以及γ-氨基丁酸。其加工品也都不同程度地保持了黑莓的营养特点。黑莓汁饮料和黑莓果酱值得大力开发。     

中国人头发截面大小和形态的初步观察

本文观察了91名中国人头发的截面特征,包括短径、长径、截面指数和截面积,并与其他种族进行了比较。发现中国人头发最粗,截面形状较接近圆形,唯长径显著小于黑人。本文还对头发截面特征的性别差异和个体差异进行了变差分析。根据本文的观察结果,对司法鉴定中头发的形态学检验问题提出了初步意见。     

SOME ASPECTS OF THE MANAGEMENT OF BILATERAL CALCULUS DISEASE OF THE KIDNEY

In the diagnosis of bilateral calculus disease of the kidneys, it is important to differentiate between cystine, uric acid, calcium oxalate and phosphate renal lithiasis. Methods for distinguishing one from another are described.Dietary therapy is the method of choice for cystine and uric acid lithiasis.In calcium and phosphate urolithiasis, dietary therapy is a very useful adjunct. It must be regulated by careful studies of its effect on urinary calcium precipitability, a new test for which is described based upon the demonstration of the existence of two forms of calcium in the urine.Irrigation therapy for calcium phosphate and phosphate lithiasis is briefly discussed.Surgical therapy for large renal phosphatic calculi is discussed to show how considerations of renal counterbalance and urinary calcium, magnesium and phosphate excretion through damaged kidney substances influence the surgical plan in each case.     

松毛虫卵期几种寄生蜂的共寄生现象及其对寄生率的影响

松毛虫赤跟蜂 Trichogramma dendrolimi Matsumura 白跗平腹Pseudanastatusalbitarsis Ashmead松毛虫宽缘金小蜂Pachyneuron olitarium(Harig), 松毛虫黑卵蜂 Telenomus dendrolimusi Chu和大蛾卵跳小蜂Ooenvyrtus Kuwanae(Howard)是松毛虫卵期几种主要寄生蜂。通过对上述几种寄生蜂寄生习性的研究表明：赤眼蜂和平腹小蜂不但能寄生新鲜害虫卵,还可以寄生对方已寄生并巳发育1-3天的寄生卵,但羽化串均不高;松毛虫宽缘金小蜂不寄生新鲜害虫卵,专门寄生赤眼蜂寄生后巳发育1-7,天的寄生卵,其中又以赤眼蜂发育3-5天的卵寄生串和羽化率为最高。除赤眼蜂和平腹小蜂可以混合使用外,其它蜂种混用都不同程度地存在相互排挤的现象。如果先让平腹小蜂寄生尔后再让赤眼蜂寄生或先让赤眼蜂寄生,尔后再让跳小蜂或黑卵蜂寄生,能够提高卵块寄生串和充分发挥各自天敌的作用。     

医院内新生儿手掌菌群的调查

本文对１１５例产科分娩的正常新生儿手掌细菌菌群的种类、分布及其药物敏感性进行了调查。结果表明,出生１～１２小时的新生儿感染率为５７８％,１２～２４小时的新生儿感染率为７５％,２４小时～５天的新生儿感染率为９７１％。共检细菌１６１株,其中革兰氏阳性细菌１３５株,占８３８％,包括金黄色葡萄球菌８７株,占５４０４％;表皮葡萄球菌８株,占４９６％;腐生葡萄球菌２株,占１２４％。革兰氏阴性细菌２６株,占１６１５％。包括大肠埃希氏菌１２株,占７４５％;阴沟肠杆菌３株,占１８６％;异型枸椽酸杆菌３株,占１８６％;丙二酸盐阴性枸椽酸杆菌６株,占３７３％。所检出的细菌对丁胺卡那霉素和氟哌酸敏感率较高,分别为９４２％和３７４％,对青霉素、氨苄青霉素、庆大霉素、西力欣、头孢三嗪均耐药。生产方式和性别与感染率无显著相关性。     

EVALUATION OF THERAPY OF PERIPHERAL POLYNEURITIS

Peripheral polyneuritis is not a disease entity but a mystery. The underlying cause should be searched for, but since often it cannot be found, treatment should be started simultaneously with the search. Conservative measures should be tried first—vitamin B complex, niacin, riboflavin, pyridoxine and thiamine chloride; next, injections of liver extract. Then, if no specific condition amenable to treatment has been discovered and if the patient is seriously incapacitated and becoming worse, hospitalization for trial with BAL is indicated.     

INHIBITION OF CONTRACTION RESPONSES OF HYDRA

The contraction reponse ot hydra to intermittent light stimulationmay be inhibited by exposing the animal to reduced glutathione(GSH). Such inhibitory acthity is dependent on: (1) the concentrationof GSH; (2) the pH of the medium; (3) previous exposure to GSH;and (4) the nutritional state of the animal. Hydra adapt tolO^–5 M GSH so that after approximately an hour the frequenciesof lightinduced contractions are restored to control levels.Such adaptation to GSH is due to changes occurring within theanimal rather than to the degradation of the glutathione molecule.S-methyl glutathione blocks contractions in response to light,showing that the sulfhydryl group is not essential for inhibition.Analogs with sterically large groups substituted for the sulfhydrylgroup, such as oxidized glutathione and S-acetyl glutathione,have no inhibitory activity. These compounds, however, reducethe inhibitory effect of GSH, indicating competition for theGSH receptor. Contractions of hydra in response to intermittent mechanicalagitation are also inhibited by GSH. The duration of inhibitionis dependent on the GSH concentration. Both oxidized glutathioneand S-acetyl glutathione reduce the inhibitory effect of GSH. Hydra adapted to the dark for 24 hours show a marked suppressionof contractions in response to mechanical agitation when exposedto light. On exposure to light, such animals elongate to approximatelyone and a half times their dark adapted length, and are relativelyinsensitive to agitation. The mechanisms by which such stimuliinhibit the contraction responses of hydra remain to be determined.     

文昌鱼Sertoli细胞超微结构的进一步研究

用光镜和电镜技术观察厦门文昌鱼(Branchiostoma belcheri Gray)精巢中Sertoli细胞在不同发育时期的细微结构后发现:精巢发育Ⅰ—Ⅱ期,Sertoli细胞贴近基底膜,与生殖细胞相间排列;Ⅲ—Ⅳ期时,逐渐向管腔方向移动;这种细胞在核的顶部及其周围胞质中,有丰富的粗面内质网、发育良好的高尔基复合体、大量溶酶体及糖元颗粒,并可见精细胞附着在Sertoli细胞的胞质中。据此,我们认为Sertoli细胞具有营养、吞噬和释放精子的功能。本文旨在为研究这种细胞的内分泌功能提供有价值的依据。     

猕猴桃嫁接试验

本文报道猕猴桃不同嫁接时期、嫁接方法和不同分类群的砧木试验结果,猕猴桃最适宜的嫁接时期是落叶后至翌年萌芽前,嫁接方法以切接为好,嫁接成活率均在90％以上。同种和同一分类群的砧穗间有良好的亲和力,嫁接均有较高的成活率。不同分类群间嫁接效果较差,如中华猕猴桃桂海4号嫁接于中华猕猴桃砧木上的成活率,生长情况均比嫁接其它分类群为砧的有显著差异。     

GENETICS OF RESISTANCE OF SALIX SERICEA TO A DIVERSE COMMUNITY OF HERBIVORES

We measured resistance of Salix sericea, the silky willow, to a diverse assemblage of 12 herbivores. We investigated the potential for multispecies coevolution among these herbivores by measuring genetic correlations between pairs of herbivores interacting within the component community. After measuring herbivore attack on half-sib families of potted S. sericea during three years, we found significant narrow-sense heritabilities of resistance to Phyllonorycter salicifoliella and Phyllocnistis sp. in 1991. Thus, there is the potential for selection on resistance to these two herbivores. Despite the many significant phenotypic correlations between herbivore abundances within a year, most genetic correlations between herbivore abundances within a year were not significant. The genetic and phenotypic correlation structure varied from year to year in this three-year study. Thus, it appears that there is the potential for evolution of resistance to the two herbivores for which we found significant heritabilities, but multispecies coevolution seems unlikely.     

蜀龙头骨及脑颅的解剖

本文对蜥脚类蜀龙(Shunosaurus)的脑颅分别从其头骨特征、脑垂体、耳区、视觉系统、脑神经等诸方面进行了较为详细的解剖研究,结果表明 Shunosaurus 内颈动脉不分叉;基蝶骨突强烈收缩;外淋巴囊出现在中耳及 IX、X、XI 孔与颈静脉孔内分外合等现象十分独特.因此,Shunosaurus 应视为一种特化的原始蜥脚类.     

亚热带地区部队皮肤真菌病及其病原菌的调查研究

亚热带地区是皮肤真菌病的高发地区,据报道,云南边防某部皮肤真菌病发病率为57.8％,占皮肤病发病率的第一位,美军在越南战争期间,发生的所有皮肤病中,最常见的是皮肤真菌感染,而且造成了非战斗减员。战争后期,美军把皮肤病的防治作为其疾病防治的重点。因此,我们于1992年10月底对海南地区部队皮肤真菌病的发病情况进行了流行病学凋查,并对皮肤真菌病的病原菌进行了分离鉴定,现报告如下。     

ULTRASTRUCTURE OF AUXIN-INDUCED TUMORS OF THE COLEORHIZA-EPIBLAST OF WHEAT

When wheat is germinated in high concentrations of certain auxins, the coleorhiza-epiblast grows in an excessive and disorganized manner and resembles a callus. Wheat was germinated in 10⁻³ M indoleacetic acid or in water. There was greater net synthesis of DNA, RNA, and protein in the tumor tissue than in control tissue. Control and tumor tissue was fixed for electron microscopy 1, 2, 3, and 4 days after sowing. In contrast to the controls, many more lipoidal bodies appeared in 1-day-old, auxin-treated tissue and thereafter diminished in number. In 2- and 3-day-old tumor tissue, small membraneous fragments were prominent but disappeared in older tissue. With time, the following changes became progressively more pronounced: cytoplasmic vacuolation, appearance of myelin figures, polyribosome configurations and extensive profiles of rough endoplasmic reticulum, and sloughing of cytoplasmic contents into and accumulation of electron-dense material in vacuoles. Possible factors in susceptibility of certain tissues to tumor formation are discussed.     

A QUANTITATIVE ANALYSIS OF THE MEGAGAMETOPHYTE OF FIVE SPECIES OF CORNUS L.

Comparisons of variations of morphological features, treated quantitatively, of the megagametophytic stages in Cornus asperifolia Michaux., C. stricta Lam., C. amomum Miller, C. florida L., and C. alternifolia L. suggest differences in growth patterns of their megagametophytes. The successful application of the clearing fluid 41/2 (Herr Fluid) affords adequate data for assessment of quantitative features of such minute plants. This method, less time consuming than traditional paraffin sectioning techniques, allows for statistical treatment of a sufficient number of species for valid inferences of angiospermous embryological features. An investigation of megagametophytic size was directed both to successive stages within each species and to each stage among all five species. In both instances, means, confidence intervals (CI), and growth increments (GI) were compared. Without exception, the largest means for length and width occurred in the 8-nucleate stage for all species. The greatest GI for length occurred in the 8-nucleate stage for C. stricta, C. alternifolia, and C. asperifolia and in the 4-nucleate stage for C. florida. The 4- and 8-nucleate GI were nearly equal for C. amomum. Overlapping of 95 % CI between successive stages indicated uniform growth between stages for the megagametophyte. Only C. asperifolia had CI overlapping between all successive stages for length and width. These five species are clearly separated on the basis not only of variations in qualitative features but also on megagametophytic growth patterns among species.     

THE EFFECT OF THE CONCENTRATION OF ENZYME ON THE RATE OF DIGESTION OF PROTEINS BY PEPSIN

1. In certain cases the rate of digestion of proteins by pepsin is not proportional to the total concentration of pepsin. 2. It is suggested that this is due to the fact that the enzyme in solution is in equilibrium with another substance (called peptone for convenience) and that the equilibrium is quantitatively expressed by the law of mass action, according to the following equation. See PDF for Equation It is assumed that only the uncombined pepsin affects the hydrolysis of the protein. 3. The hypothesis has been put in the form of a differential equation and found to agree quantitatively with the experimental results when the concentration of pepsin, peptone, or both is varied. 4. Pepsin inactivated with alkali enters the equilibrium to the same extent as active pepsin. 5. Under certain conditions (concentration of peptone large with respect to pepsin, and concentration of substrate relatively constant) the relative change in the amount of active pepsin is inversely proportional to the concentration of peptone and the equation simplifies to Schütz''s rule. 6. An integral equation is obtained which holds for the entire course of the digestion (except for the first few minutes) with varying enzyme concentration. This equation is identical in form with the one derived by Arrhenius for the action of ammonia on ethyl acetate. 7. It is pointed out that there are many analogies between the action of pepsin on albumin solutions and the action of toxins on an organism.     

中国水仙六倍体的诱导和染色体数目的变异(简报)

中国水仙(Narcissus tazetta L.var.chinensis Roem)属于石蒜科水仙属多年生草本花卉植物。中国水仙的品种不多,在福建漳州地区主要栽培品种为单瓣水仙,此外,还有重瓣和“金三角”两个品种。中国水仙为三倍体植物,染色体数目为2n=3x=30[1-3],其高度不孕性,只开花不结实,靠子鳞茎进行无性繁殖繁衍后代。由于长期的无性繁殖和病毒感染,现存种质退化、品质下降,花朵数明显减少、香味变淡、生长势差、鳞茎变小、抗性减弱等问题,严重影响了该花卉的进一步生产和发展。因此,采用现代生物工程技术(体细胞杂交技术、转基因技术等)改良中国水仙,培育中国水仙新品种迫在眉睫。     

乙酰胆碱对培养T细胞功能的作用

本文研究不同浓度（１０＾－１０－１０＾－４ｍｏｌ／Ｌ）乙酰胆碱（ＡＣｈ）对离体培养的大鼠脾脏Ｔ淋巴细胞增殖的影响,并探讨其作用机制。实验结果表明：１０＾－９－１０＾－４ｍｏｌ／Ｌ可显著增强Ｔ细胞由刀豆素Ａ（Ｃ－Ａ）诱导的增殖反应,以１０＾－７－１０＾－６ｍｏｌ／Ｌ时最强。淋巴细胞先用ＡＣｈ刺激１ｈ或者刺激１ｈ后洗弃ＡＣｈ,再用ＣｏｎＡ诱导６ｈ的Ｔ细胞的增殖。１０＾－７－１０－６ｍｏｌ／Ｌ阿托品可阻     

森林群落类型分布的方位信息识别

本文通过对森林航空遥感图片经光学付里叶变换所获得的频谱分布曲线,应用模糊数学中的方位信息比较法,在不同类型森林的遥感图片的频谱之间建立了——对应的模糊关系,进行了对森林遥感图象的模式识别,并给出了与实际情况相一致的判别结果。