Non-Immunological Precipitation of Serum by Sodium Dodecyl Sulfate in Agar Diffusion

Marmoset serum or serum of other species of animal may react with sodium dodecyl sulfate and forms nonspecific precipitin lines in agar diffusion. The protein detergent complexes are not readily dialyzable. Therefore precipitin lines derived from studies that use sodium dodecyl sulfate-treated antigens in agar diffusion must be interpreted with caution.     

Nonspecific Precipitation of Serum Proteins by Sodium Lauryl Sulfate in Agar Diffusion and Immunoelectrophoresis

The anionic detergent sodium lauryl sulfate (SLS), in a final concentration of 0.1% and greater, reacted with whole serum in agar diffusion and immunoelectrophoresis to form artifactual precipitin lines. These lines occurred when either Ionagar or agarose was used as the supporting gel and were not affected by the presence of urea and 2-mercaptoethanol. Analytic chemical tests confirmed that the precipitating agent is SLS, and staining techniques showed that the detergent precipitates both protein and lipoprotein components of whole serum. Multiple artifactual precipitin lines occurred with a wide variety of animal sera, and a single line formed with human 7S immunoglobulin. Hence, in agar diffusion studies in which SLS is present in the test system, these artifactual lines may be easily misinterpreted as true antigen-antibody precipitin reactions.     

Precipitation Reactions in Agar Between Swine Serum and Homologous Pancreas Extracts

Hyperimmune anti-hog cholera and nonimmune swine sera yielded approximately 50% more precipitation reactions in agar-gel diffusion tests with pancreas extracts from SPF noninfected swine than with extracts obtained from swine experimentally infected with virulent hog cholera virus. The pancreas-reacting property of swine serum was determined to be relatively heat stable, withstanding 68 C for 30 minutes. Of various swine serum fractions tested, the only one that reacted with pancreas extracts contained gamma, beta and alpha-globulins. In the absence of alpha-globulin, precipitation reactions were not observed. Sera of newborn SPF piglets, containing 50% alpha-2 globulin, formed more intense precipitation lines with swine pancreas extracts than were formed by the sera of their dams with the same extracts. The pancreas-reacting activity of swine sera was completely removed by absorption with pancreatic tissue. This property was not removed by absorption with guinea pig kidney, or beef, swine or human erythrocytes. Maceration of pancreatic tissue released reactive substances in a polydispersed form. This was demonstrated by the ability of almost all supernates and sediments from differential centrifugation of such preparations to form precipitation lines with swine sera. Reactive substances from swine pancreas were found to be relatively heat labile, being inactivated in one hour at 56C. No evidence was obtained in this study to indicate that the observed precipitation reactions were related to hog cholera virus and its corresponding antibody. The reactions are believed to have resulted from the interaction of protein-related substances present in normal swine pancreas with a relatively heat stable component, possibly alpha-globulin, in swine serum.     

Serological Comparison of the Three Morphological Phases of Coccidioides immitis by the Agar Gel Diffusion Method

Hyperimmune sera against spherules and against arthrospores of Coccidioides immitis were prepared by inoculation of rabbits. The antibody content of these sera was studied by the agar gel diffusion method. It was observed that antispherule pooled sera formed multiple precipitin bands with extracts of spherules and of arthrospores. The antiarthrospore pooled serum, however, failed to precipitate with the spherule extract, and formed a single band in the presence of an arthrospore solution. When the spherule and the arthrospore extracts were tested with a variety of different antisera, it was observed that the spherule preparation formed bands only in combination with anti-purified spherule pooled serum, whereas the arthrospore extract precipitated with anti-purified spherule, antiarthrospore, and anti-Histoplasma capsulatum pooled sera. It was also observed that a spherule culture supernatant solution formed five precipitin bands in combination with anti-spherule pooled sera, formed one band with pooled antiserum from rabbits with coccidioidomycosis, and did not precipitate in the presence of antiarthrospore pooled serum. Coccidioidin, however, formed two bands in the presence of any of these antisera. It was therefore concluded that extracts from the spherule phase of C. immitis differed from solutions obtained from the arthrospore and mycelial phases.     

Antimicrobial Residues in Milk. Comparison of Different Agar Diffusion Methods

Different agar diffusion methods were compared in order to find a sensitive method for the detection of various antimicrobial residues in milk. A total of 588 producer milk samples were analyzed using subsets of the most sensitive methods. With the IDF method, 2 positive cases (0.34 %) appeared among the producer milk samples, with the Thermocult method 13 positive cases (2.21 %) and with the Test agar pH 8 method with trimethoprim and glucose 4 positive cases (0.68 %). A combination of the IDF method and the Test agar pH 8 method resulted in 6 positive cases (1.02 %) and a combination of the Thermocult method and the Test agar pH 8 method in 17 positive cases (2.89 %). With penicillinase 41 % of the positive cases were identified as β-lactam antibiotics and with p-aminobenzoic acid 18 % of the positive cases were identified as sulphonamides. 41 % of the positive cases remained unexplained. The best combination for the detection of antimicrobial agents in milk seems to be that of the Thermocult method and the Test agar pH 8 method with trimethoprim and glucose.     

Prolongation of Microbiological Air Sampling by a Monolayer on Agar Gel

The useful life of agar in aerosol samplers is greatly extended by treatment with a dilute emulsion of oxyethylene docosanol. Growth of viable organisms is unaffected.     

Saponin Adjuvants. IV. Evaluation of The Adjuvant Quil a in the Vaccination of Cattle Against Foot-And-Mouth Disease

The saponin adjuvant Quil A has been investigated in the vaccination of cattle against foot-and-mouth disease. Using a Frenkel type vaccine a dose-response relationship has been established between Quil A and neutralizing antibody titres. Ten ml of vaccine was combined with 0, 50, 200, 800, and 3200 µg of Quil A. The combinations were each injected into 4 animals. The local reaction on the site of injection produced by injection of the vaccine alone and in combination with different doses of Quil A has been estimated. On this basis a therapeutical dose at 1 mg of Quil A has been estimated to combine maximum adjuvant effect with a minimum of adverse reactions. This dose has been tested in the vaccination of cattle with FMD vaccines derived from BHK suspension cell virus of type O and A respectively. The vaccines were tested in 10 ml and 5 ml doses with or without Quil A, and each in 4 animals. It is concluded that Quil A is a valuable adjuvant for use in the induction of neutralizing antibodies against foot-and-mouth disease in cattle.     

Gibberellin-like Substances Obtained from Chilled Plants of Dianthus barbatus L. by an Agar Diffusion Technique

Plants of Dianthus barbatus with a cold requirement for floweringwere subjected to chilling treatments at 5 °C. An agar diffusiontechnique was used to collect gibberellin-like substances fromshoot tips excised from these plants and from plants that hadbeen kept in the glasshouse at a minimum temperature of 14 °C.Shoot tips from chilled plants gave markedly higher yields ofgibberellin-like substances. The effect of chilling was no longerso apparent if plants were returned to the higher temperaturesof the glasshouse for 1 week before the shoot tips were excised. The proportion of plants that flowered as a result of the differentchilling treatments varied widely but this variation was notassociated with any obvious differences in the yields of gibberellin-likesubstances. Application of gibberellins to plants grown at aminimum temperature of 14 °C did not promote flowering.     

Agarose Gel Electrophoretic Fractionation of Serum Proteins in Adult Cattle. II. A Study Of Cows with Different Diseases

In 283 dairy cows suffering from internal disorders the serum proteins were studied by agarose gel electrophoresis supplemented by total protein and albumin determinations. The clinical diagnoses could be grouped according to protein pattern. Group 1 (abomasal displacement and traumatic muscle injury) did not appreciably affect the serum protein concentrations and represented primarily non-inflammatory diseases or diseases of non-infectious origin. Group 2 (leukosis) occupied an exceptional position, with heavy lowering of albumin unaccompanied by a corresponding rise of total globulin. The γ-globulin concentration was significantly lowered. Group 3 (acute traumatic peritonitis) represented an acute inflammatory process with increase chiefly of the α-globulins, while the γ-globulin concentration was normal. Group 4 (chronic traumatic peritonitis, summer mastitis, chronic subclinical mastitis, chronic laminitis and polyarthritis, urinary tract infection, abscess, and sub-acute-chronic pneumonia) comprised diseases chiefly of chronic inflammatory character and with infectious origin. Especially characteristic was the heavy rise of globulins in general and of γ-globulin in particular. In most cases there was a large increase also of the α- and p-globulin fractions.     

Saponin Adjuvants. Vi. The Adjuvant Activity of Quil a in Trivalent Vaccination of Cattle and Guinea Pigs Against Foot-And-Mouth Disease

The saponin adjuvant Quil A was investigated in trivalent vaccination against foot-and-mouth disease with a concentrated vaccine based on BHK suspension cell virus of the serotypes O, A and G. The activity in cattle was estimated on the basis of seroneutra-lizing antibodies. Five and 10 ml doses with or without 1 mg of Quil A were each injected into 6 animals. Seroneutralizing antibodies were estimated at regular intervals during a period of 29 weeks. The activity in guinea pigs was estimated by experimental challenge. One ml doses of serial 4-fold dilutions of the vaccine with or without 50 µg of Quil A were injected into 24 groups of 20 guinea pigs. Challenge was given 3 weeks after vaccination. It was concluded that Quil A showed adjuvant activity in cattle and guinea pigs with all the serotypes used in the trivalent vaccination.     

Detection of Chlamydial Antibodies in Animal Sera by Double Diffusion in Gel

Postinoculation sera collected from pigeons, turkeys, guinea pigs, sheep, a calf, a rabbit, and a horse experimentally infected with various strains of Chlamydia psittaci yielded a high incidence of positive reactions when tested by double diffusion in gel. Antigen was a deoxycholate extract of SA-2 strain of C. trachomatis. Good correlation was obtained with results of complement fixation tests, whereas double diffusion in gel was less sensitive. Immunoelectrophoresis of the antigen revealed presence of two antigens in the extract.     

Agar Diffusion Method for Negative Staining of Microbial Suspensions in Salt Solutions

Microbial suspensions in a saline medium can be prepared for negative staining by a simple agar diffusion method that achieves a high degree of particle concentration.     

12. Separation of Small Infective Components of MEFj Poliomyelitis and Horsesickness Viruses by Migration into Agar Gels

ABSTRACT

From gel diffusion experiments it is concluded that the slower sedimenting components of MEF, poliomyelitis and African horsesickness viruses are definitely smaller particles than the infective components with higher sedimentation constants. They were capable of migrating into agar gel which held back the components with higher sedimentation constants. The possibility that their differing sedimentations on centrifugation depend on factors other than size, such as lipoid content, can therefore probably be excluded. In the case of horsesickness virus an additional infective component with a sedimentation constant of approximately 100 S was shown. This is additional to the two components with sedimentation constants of 180 S and 476 S which have been previously identified (Poison and Madsen*).     

张昌颖教授生平

张昌颖教授是我国著名的生物化学家、教育家,中国共产党党员,是一位在我国生物化学界受到广泛尊敬和爱戴的老前辈。张昌颖教授于1906年2月14日出生于四川省富顺县一个书香世家。1921-1923年,张教授就读于四川成都高等师范附属中学。由于自幼勤奋好学、奋发努力,于1923年考进清华学校(清华大学前身)读书;就读清华学校期间又考取了官费留美预备班,并于1929年赴美留学,在威斯康辛大学攻读化学专业、先后以优异成绩获学士(1931年)、硕士(1932年)及博士(1933年)学位。1933-1934年,就职于美国威斯康辛大学农学院。上个世纪30年代的旧中国灾难深重…     

An Egg-yolk Agar Diffusion Assay for Monitoring Phospholipase C in Cultures of Clostridium welchii

An egg-yolk agar diffusion assay of phospholipase C has been developed and investigated. The results demonstrate the necessity for strict control of the pH and volume of the egg-yolk agar and of the temperature and duration of incubation of the assay plates. The method has been used to monitor phospholipase C production in cultures of Clostridium welchii sparged continuously with CO₂ in N₂ and shows that maximal concentration occurs after ca. 6-8 h incubation at 37°C. The concentration falls slowly during subsequent anaerobic incubation supporting the opinion that Cl. welchii may elaborate a proteinase which destroys phospholipase C.