摘要:

FiveEscherichia colistrains were established as antigenic test strains for five new polysaccharide K antigens: K95, K96, K97, K98 and K100. K95 to K98 served already as test strains of O antigens O75, O77, O81 and O107, respectively. F147, which is test strain of K100, had O antigen O75.

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01947.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Staphylococcalα‐toxin was produced in a fluid medium based on acid hydrolysed casein using strain Wood 46.α‐Toxin and several other proteins were precipitated from bacteria‐free culture supernatants by heating at 60° C for 20 min. The process was influenced by the pH of the solution. The toxin was completely inactivated and the precipitate contained a number of proteins if the pH of the solution was adjusted to 4.0–5.0. Heat precipitation of solutions having a pH of 6.0–7.0‐ resulted in a partial inactivation ofα‐toxin. The precipitates at this pH contained less of the additional proteins and had higher relative amounts ofα‐toxin than precipitates formed at a lower pH. The precipitate was dissolved in 8 M urea with the resultant activation of the haemolysin. Pureα‐toxin with a molecular weight of 39,000 was obtained by electrophoresis in 8 M urea at pH 8.6 in ordinary tubes for polyacrylamide electrophoresis. The separation time was 45 min. The minor component ofα‐toxin with a pI of 7.4 could be demonstrated by the same method. A non‐haemolytic protein with a molecular weight of 27,500 which existed in at least two charged forms, was shown to have an antigenic relationship to the toxin with

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01948.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Prolonged cultivation of strain Wood 46 in fluid cultures resulted in a selection of mutants with low or no haemolytic activity. In one group of mutants, four out of five strains showed no production ofα‐toxin when examined by polyacrylamide gel electrophoresis and by double diffusion in agar. Two major extracellular proteins which have been identified by other methods as degradation products ofα‐toxin were also absent. The absence ofα‐toxin did not affect growth in fluid or solid media. Fibrinolysin was produced by these mutants but at a much lower rate than by the wild type. A second group of mutants was characterized by a slow rate of growth on rabbit blood agar and showed a heterogeneous extracellular protein pattern. These mutants had a high growth rate in fluid medium consisting of acid hydrolysed proteins. Production of fibrinolysin was absent or low in three out of four mutants in the second group. The slow growth and low production ofα‐haemolysin in rabbit blood agar probably was caused by deficient extracellular proteolytic activity of

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01949.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The importance of the species of blood employed for detection of haemolysis in seventy‐seven Haemophilus strains of human and porcine origin was studied. Significant differences in the visibility of haemolytic zones obtained on the different blood agar media were observed. In decreasing order, the suitability of the species of blood was: calf, sheep, human, rabbit, poultry and horse blood. On plates containing washed sheep or calf red cells the haemolysin of all 36 strains ofHaemophilus pleuropneumoniaeacted synergistically with the β‐toxin of theStaphylococcus aureusstrain used as “feeder strain”, giving rise to a lytic phenomenon resembling the CAMP

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01950.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Serum samples from people born between the years 1895 and 1970 were collected and tested for antibody to hepatitis B surface antigen (anti‐HBs) by passive haemagglutination (PHA) and radioimmunoassay (RIA), and for antibody to hepatitis B core antigen (anti‐HBc) by immunoelectroosmophoresis (IEOP). Neither anti‐HBsnor anti‐HBcwas detected in the serum from anyone under 15 years of age. The prevalence of anti‐HBsand anti‐HBcshowed peaks of 9.2 and 8.3 per cent, respectively, in the age group of 40–49 years. The distribution of antibody was equal between men and women. Eighty per cent of the sera with anti‐HBswere also positive for anti‐HBc. All sera positive for anti‐HBcalso

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01951.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The effect of human leukocyte interferon on cultured U‐amnion cells was examined, and several biological parameters were registered. Multiplication of Vesicular stomatitis virus and the virus‐produced cytopathogenic effect was prevented. The growth rate of uninfected cells was reduced, as well as the spontaneous release of3H‐uridine. These effects were observed following treatment with 10 units of interferon per ml. No morphological alterations could be detected by scanning electron microscopy after 24 or 72 hours treatment with up to 2000 units interferon p

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01952.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

During the years 1966–1974, 167,297 strains isolated from 167,297 patients or staff members in Danish hospitals were registered at Statens Seruminstitut. All the strains were phage‐typed and examined for production of a ‘Tween’‐80‐splitting enzyme and resistance to mercuric chloride. 158,236 strains were examined for resistance to antibiotics. Since 1968, a steep decrease in the number of strains resistant to three or more antibiotics (multiple‐resistant) and in strains of the 83A complex was noticed. In recent years an increase in strains belonging to phage‐group I and in those referred to as miscellaneous and non‐identified was registered. The increase in the non‐typable strains might be explained by the shift of the concentration of the typing phages from 1000 X RTD to 100 X RTD. It is concluded that at least two factors may have contributed to the reduction of the multiple‐resistant strains: an altered antibiotic policy, restricting the use of streptomycin and tetracyclines, and an improved hospital hygiene, diminishing the spread of identical strains within the various departments. However, it is emphasized that the consumption of methicilli

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01953.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Neomycin, chloramphenicol, gentamycin, rifampicin and oxytetracycline were tested for their influence on virusinduced interferon (IF) production in mice. Repeated intraperitoneal (i.p.) injections of antibiotics were given to produce significant serum concentrations during the time of IF production, induced by i.p. injections of Newcastle disease virus (NDV). IF titres in antibiotic‐treated mice determined 6 hours after induction were compared to titres in control mice given NDV only. The IF production was not significantly modified in most of the antibiotic treated mice. Only the highest dose of chloramphenicol (2500 μg/mouse) appeared to cause a reduction in IF production (p<0.10). Addition of antibioticsin vitrodid not alter the antiviral titres of

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01954.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Human sera collected at the end of 1975 were studied for HI antibodies to influenza A/Mayo Clinic/103/74 (Hsw1N1). The frequent occurrence of these antibodies in subjects born before 1930 suggested that they are present in about 25 per cent of the Finnish population. During the H3N2 epidemic in winter 1975–76 a low response of antibodies to A/swine‐like viruses was recorded in about half of the influenza patients with a pre‐existing titre, but not in any of the patients without pre‐existing antibodies. A comparison of samples collected in 1969 and 1975 suggested that at the community level the antibodies to A/swine‐like viruses have not decreased during the era of the H3N

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01955.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Groups of red mice and CF1 mice immunized intravenously with varying doses of a weak or a strong strain of BCG or a strain ofMycobacterium tuberculosiswere challenged 3 weeks after immunization with 0.1 or 0.2 ml 10‐2Listeria monocytogenesinjected intravenously, simultaneously with a non‐immunized control group. The acquired resistance was determined on the basis of the number of survivors and the survival times of the animals that died spontaneously. In the red mice, the strong BCG strain induced a definitely higher resistance than the weak strain, and theM. tuberculosisstrain a slightly higher resistance than the BCG strains. As in red mice, the resistance of CF1 mice was higher in animals immunized withM. tuberculosisthan in those immunized with the BCG strains. However, the difference in the survival times of mice immunized with the two strains of BCG was much less than in red mice, and was only clearly significant as regards one of the doses used. The relationship between the virulence of a mycobacterial strain and its ability to induce acquired resistance against an infection with listeria or against an infection with virulent tubercle bacilli is discussed. It is concluded that red mice are more suitable than CF1 mice for evaluation of the protective potency of a BCG str

ISSN:0304-131X    

DOI:10.1111/j.1699-0463.1976.tb01956.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY