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W Köhler

Publications and source records attributed to W Köhler.

At least 145 records · Page 8Linked to original sources
PubMed1984

Quantitative differences in specific binding of fibrinogen fragment D by M-positive and M-negative group-A streptococci.

Selected M-positive and M-negative group-A streptococcal strains were investigated with respect to their selective absorption of plasmin fibrinogen degradation products (FDP) in a simple batch technique. After incubation of killed streptococci with the FDP mixture, the centrifuged supernatants were investigated by SDS-electrophoresis and the binding capacity of the strains was calculated by evaluation of the scanning curves of stained gels. It was found that there is a specific uptake of the C-terminal fragment D by both M-positive and M-negative strains. Although the M-positive strains bound more fragment D (30%-80%) than did the M-negative strains (10%-15%), it could be clearly shown that the loss of M-protein was not necessarily linked with a total disappearance of fibrinogen binding activity. Fragment D blocked the agglutination of streptococci by fibrinogen. Washing the streptococci preincubated with FDP with a 0.1 M citric acid, 6 M urea buffer, pH 3.0, restored agglutination. Treatment of FDP-incubated bacteria with this buffer was found to be a means of recovering pure fragment D from streptococcal cells. It is suggested that M-positive and M-negative streptococci have qualitatively similar binding sites. These receptors might be reduced in the M-negative streptococci. Human serum albumin and Tween 20 did not influence the interaction between streptococcus and fibrinogen.

Agglutination↗
PubMed1984

[T-proteins of Streptococcus pyogenes. IV. Isolation of T1-protein using affinity chromatography on immobilized fibrinogen].

T-protein of Streptococcus pyogenes, type 1 (strain SF 130 Griffith) was extracted by enzymatic treatment of the cells with trypsin and partially purified by ion exchange chromatography on DEAE cellulose and gel chromatography on ultrogel ACA 44. The crude T protein still showing serologically type specific and cross reactions finally was applied to a fibrinogen sepharose column. Components eluted with the neutral buffer (0.05 M phosphate, 0.2 M NaCl, 0.02% NaN3, pH 7.0) reacted serologically in the same manner as the crude T protein. By using 0.1 M citrate, 6 M urea pH 3.0 buffer a type specifically reacting protein (T1-TRYP-F) was eluted from the fibrinogen column. T1-TRYP-F showed identical precipitation lines with the recently characterized T1-protein (T1-TRYP-I) purified by immunochromatography on type specific anti-T antibodies. Comparison of the SDS-patterns of T1-TRYP-F and T1-TRYP-I revealed a less complex molecular size subunit structure for the fibrinogen binding T1-TRYP-F (two bands of 60000 and 70000) as found for T1-TRYP-I, which showed serologically active peptides between 30000 to about 500000. It is discussed that T protein also may be linked covalently with fibrinogen receptors as it has been reported for M protein.

Amino Acids↗
PubMed1984

Comparative studies on surface hydrophobicity of streptococcal strains of groups A, B, C, D and G.

Cell surface hydrophobicity of group A, B, C, D and G streptococcal strains has been studied and compared in a new test based on the fact that the degree of bacterial aggregation in ammonium sulphate depends on amphiphilic surface antigens. M-positive group A strains showing good growth in normal human blood aggregated in the standard salt aggregation test at very low concentrations of ammonium sulphate, while M-negative strains, which were killed in normal human blood, usually aggregated at high salt concentrations. Agents such as 2 M-KSCN, 2 M-guanidine. HC1 or 2 M-urea decreased the aggregation of the M-positive strains in the salt aggregation test while non ionic detergents such as Tween 20 (1%, w/v) and ethylene glycol (2 M) did not affect cell aggregation. Binding of fibrinogen and albumin resulted in a decrease of surface hydrophobicity of the group A M-positive strains. Group B strains possess a hydrophilic surface character and did not aggregate, while group C and G strains behaved in the salt aggregation test like M-negative strains of group A streptococci. Group D strains did not aggregate even at high ammonium salt concentrations. The results are discussed in relation to the influence of lipoteichoic acid and other surface antigens on strains of the various groups, and it is suggested that M protein and possibly also other surface proteins contribute to the high surface hydrophobicity of group A strains.

Ammonium Sulfate↗
PubMed1984

[Cultural and serologic studies of the colonization of mycoplasmas in hemodialysis and kidney transplant patients].

According to the present investigations the frequency of the proof of mycoplasms in the urine of haemodialysed patients and patients who underwent renal transplant operations does not differ from that of healthy control persons. A routine proof of mycoplasms is not proved necessary for the groups of patients examined. The standardisation of the plasms of urea--of patients with different pictures of a disease--resulted in a dominance of the Serovar III. No relation could be seen between Serovar and haemadsorption ability of the plasms of urea. The haemadsorption rate was significantly higher in isolates of patients than in isolates of healthy persons.

Adolescent↗
PubMed1984

[Isolation and characterization of erythrogenic toxins. VII. Study of the erythrogenic toxin type C produced by Streptococcus pyogenes].

Erythrogenic toxin (ET) type C was purified from culture filtrates of Streptococcus pyogenes strains NY 5, T 18, and AT 13. Methods used included ammonium sulfate precipitation, phosphate precipitation, column chromatography on CM-Sepharose and Sephadex G 100, and isoelectric focusing in Sephadex gel. The molecular weight was determined by SDS gel electrophoresis as 25,500. The preparation reacted only with homologous antiserum (anti-C), but not with antitoxins types A or B in double diffusion tests. The isoelectric point was determined to be 6.8 by analytical isoelectric focusing. Also the amino acid composition was determined. The toxin was found to be mitogenic (as well as pyrogenic and toxic for rabbits). The ET type C is digested by trypsin, pepsin, chymotrypsin and Pronase E, but is rather stable when treated with papain or streptococcal proteinase.

Amino Acids↗
PubMed1983

Isolation and characterization of erythrogenic toxins. V. Communication: identity of erythrogenic toxin type B and streptococcal proteinase precursor.

Production of erythrogenic toxin type B by Streptococcus pyogenes strain T19 was found to be strongly dependent on the pH of the cultivation medium. Maximum yields (greater than 100 mg of toxin/1) were obtained at pH 6.0. In contrast no toxin production was serologically detectable at pH values above 6.5. Purified B-toxin was shown to consist of two components when assayed by SDS-electrophoresis. The molecular weight of the two components was estimated to be 30 000 and 12 000. Isoelectric focusing revealed a heterogeneity of the preparation with isoelectric points between 8.0 and 9.0. Streptococcal proteinase precursor was isolated from culture supernatants of strains T19 and B220 by ammonium sulfate crystallization and purification on CM-Sepharose CL 6B. The protein obtained was homogeneous by SDS-gel electrophoresis and had a molecular weight of 44 000. After autocatalytic activation with mercaptoethanol two bands appeared corresponding to molecular weights 30 000 and 12 000. Isoelectric focusing of proteinase precursor preparations yielded a double band at pI 8.2-8.3. However, activation of precursor to active proteinase finally resulted in a change of the pI to 9.0. Erythrogenic toxin type B, streptococcal proteinase precursor, its intermediate activation products and the active proteinase itself reacted serologically identical with anti B-toxin antiserum. Streptococcal proteinase precursor provoked a delayed skin reaction and was pyrogenic as well as mitogenic. Its pyrogenic activity could be inhibited by antiserum against scarlet fever toxin (Wellcome Laboratories). We therefore believe erythrogenic toxin type B to be identical with streptococcal proteinase precursor. This helps to understand the heterogeneity of B toxin, its inactivation by trypsin and the different protocols for toxin production described in the literature.

Amino Acids↗
PubMed1983

Purification and characterization of erythrogenic toxins of Streptococcus pyogenes. VI. Mitogenic activity of isoelectrically focused erythrogenic toxin preparations and culture supernatants of group A streptococci.

Isoelectric focusing (IF) was used to separate erythrogenic toxins (ET) type A, B and C from concentrated culture filtrates of Streptococcus pyogenes strains. The ET's were identified by their mitogenic activity on human lymphocytes in the lymphocyte transformation test: purified ET type A appeared at pH 5.3, ET type C at pH 6.8 and ET type B at pH 7.5 to 8.5; the ET type B was only biologically active when PAGE IF was used. IF on Sephadex G 100 failed to yield active B toxin. The application of as little as 0.1 micrograms ET type A to an isoelectric focusing gel was still sufficient to detect a mitogenic peak in the eluates. ET type A was identified in nine out of 10 culture filtrates, ET type C in 4 out of 10. Detection of ET type B (identical with streptococcal proteinase proenzyme) in culture filtrates after IF proved to be difficult. Here the pH of cultivation media and the autocatalytic conversion of streptococcal proteinase proenzyme to activated proteinase have to be considered.

Bacterial Proteins↗
PubMed1983

[Effect of physical parameters on the production of streptococcal extracellular proteins in cultures with stabilized pH. II. Effect of temperature on the formation of streptococcal extracellular products].

The influence of the cultivation temperature on growth and production of extracellular proteins was examined for the group C streptococcus S. equisimilis, strain H 46 A. The temperature range studied was from 28 degrees C to 43 degrees C. The analytical methods used included the determination of enzyme activities, isoelectric focusing and crossed immunoelectrophoresis. The strain was able to grow in the entire temperature range with maximum growth at 28 degrees C. The amounts of extracellular proteins elaborated depended on both the cultivation temperature and the biomass production. The specific temperature for optimal production of certain enzymes were determined. The majority of these was produced at optimal rate at a temperature of 28 degrees C. Besides isoelectric focusing and crossed immunoelectrophoresis showed that additional proteins exist, the production of which was reduced at low temperatures. Isoelectric focusing revealed that in a temperature range from 28 degrees C to 37 degrees C approximately 28 different extracellular proteins were produced. In the same temperature range the presence of about 30 antigens was demonstrated by crossed immunoelectrophoresis.

Acid Phosphatase↗
PubMed1983

[Determination of haptoglobin by agglutination with anti-Hp on latex particles].

Human sera are able to agglutinate latex particles sensitized with antihaptoglobin serum produced from sheep. The agglutination depends on the haptoglobin types. Similar to the agglutination of T4-streptococci the titer of Hp 1-1 is very low and the titers of sera of the types Hp 2-1 and Hp 2-2 are 1:160 or higher.

Agglutination Tests↗
PubMed1982

[The significance of air contamination for the taking of blood cultures in open systems].

The importance of the air contamination, when open blood culture systems were used, was emphasized by investigation series in 20 test persons. The proportion of contaminated cultures correlated with the opening time and the size of the opening area of the culture systems applied. The moist cleaning of the room performed before the taking of the blood culture and low numbers of patients in the rooms clearly improved the portion of contamination.

Air Microbiology↗
PubMed1982

Tissue cages for study of experimental streptococcal infection in rabbits. I. Production of erythrogenic toxins in vivo.

Tissue cages implanted subcutaneously were used to infect rabbits with erythrogenic toxin (ET) producing streptococci. The in-vivo production of ET was followed during the infection by immunoprecipitation analyses of the tissue cage fluid (TCF). ET types A and C were mainly detected during the first week of infection, but, as late as 4 weeks after the inoculation, ET was occasionally found in TCF. The nonspecific mitogenic activity of ET on human lymphocytes was also used as a biological marker to recognize ET in TCF. Mitogenic activity was detected in 90% of samples during the first week. In order to characterize the mitogenic material released by growing streptococci, TCF was electrofocused in polyacrylamide gel. The eluates of sliced gels were checked for mitogenic activity and compared with a purified ET preparation containing ET types A and C. It could be verified that ET type A was produced under in-vivo conditions by strains NY-5 and SF130, while ET type C was produced by strain T18. Differences between production of toxins in vitro and in vivo might be of significance for the understanding of the pathogenetic mechanisms in streptococcal infection.

Animals↗