摘要:

The genes responsible for inducible erythromycin resistance in a set of DU 4916‐strains ofStaphylococcus aureuswere eliminated spontaneously or after exposure to ethidium bromide or heat. In transductions they were transferred into wildtype (rec+) and recombinationless (rec‐) strains at similar frequencies. If rec+ strains were used as recipients, the transfer frequencies of inducible erythromycin resistance would not be stimulated after increasing doses of ultraviolet irradiation of the phage lysate, whereas the transfer frequency of chromosomal cadmium resistance would be tenfold stimulated. These facts support the suggestion that the genes for inducible erythromycin resistance are carried on a plasmid. Treatments with acriflavine or ethidium bromide could not elucidate the connection with methicillin‐ and inducible erythromycin resis

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02235.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

A complement fixation (CF) test employing a mixture of whole bacteria from twenty non‐capsulatedH. influenzaestrains as antigen was used for studying antibodies againstH. influenzaein a group of patients with acute otitis media and in a group of children without signs of respiratory tract infection (RTI). In the group of 192 children (0–16 years of age) without RTI, CF titres were found in more than half the number of children under one month of age, while such titres were not demonstrated in children aged 1 month—1 year. Only a few children aged 1–2 years showed a CF titre, but in the subsequent age groups, CF titres were found to be present at increasing frequency, up to about 80 per cent. Sera from 141 patients with acute otitis media (96 children and 45 adults) were studied by means of samples generally obtained initially and after 10 days of penicillin therapy. The analyses showed that the initial titres of patients in Group I (H. influenzaenot isolated) were similar to those of patients in Group II (H. influenzaeisolated initially and 10 days later). The same average titres were found in Group I in samples taken after 10 days, while increased titres were registered for more than half the number of patients in Group II. The titres of children and adults with otitis media were similar. Patients whose recovery was delayed or poor showed titre increases less frequently than those who recovered within 10 days. The results of the present study using a CF test employing whole, non‐capsulated bacteria indicate the suitability of this test as a diagnostic aid in respiratory tract infection where non‐capsulatedH. influenzaeis suspected to be the infe

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02236.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Forty‐two consecutive patients with biopsy verified chronic hepatitis and available serum specimens were examined for the occurrence of Australia antigen, antinuclear antibodies, smooth muscle antibodies and mitochondrial antibodies. Twelve patients with persistent Australia antigen, but without circulating autoantibodies (group 1) were compared with twenty‐seven patients without Australia antigen, but with circulating autoantibodies (group 2). Young males with a history of serum hepatitis were predominant in group 1, while most of the patients in group 2 were middle‐aged women with an insidious onset of the disease. The biochemical activity of the liver disease was more pronounced in group 2. It is concluded, that the histological defined chronic hepatitis may include several disease entities of which at least two can be separated by the serology. The relevance of this classification is supported by the fact, that there are more patients developing cirrhosis in group 2 than in gr

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02237.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Competent and incompetent variants of five strains ofNeisseria meningitidiswere examined by negative stain electron microscopy with the aim of detecting a possible correlation between the competent state in DNA mediated transformation and the presence of special surface structures. As previously reported for species ofMoraxella, a correlation between the occurrence of fimbriae at or near the cells and a high level of competence was found. Various conditions of cultivation were investigated to see if small, previously unnoticed, differences in type of growth could exist between the competent and incompetent variants. No difference could be detected in colony morphology on solid medium. However, in statically incubated broth the competent variants were distinguished by forming a surface pellicle after one to two days of growth.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02238.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Three extracellular proteolytic enzymes are produced byStaphylococcus aureusV8. In order to develop a method to determine the activities of the individual enzymes in culture supernatants, the kinetics of the hydrolysis of casein, catalysed by purified enzymes, were studied. Using 1 per cent casein (pH 7.4) as a substrate, zero‐order reactions were obtained for all three enzymes. The Kmvalues were 0.59 per cent, 0.19 per cent and 0.29 per cent for protease I, II and III, respectively. Using previously established data on the sensitivity of the different proteases to EDTA and cysteine, a method for the determination of the activity of each enzyme in mixed samples was developed. The hydrolysis of casein in agar and agarose gels was also studied to permit interpretation of different patterns of proteolysis around colonies of staphylococci growing on casein agar media. Different types of zones were obtained in the casein agar gels with the enzymes, indicating different substrate specificities. Under certain conditions a specific pattern of proteolysis could be attributed to the activity of one of the proteases or a mixture of these. The detection limits in casein agarose gels were approximately 25 ng/ml for protease I, 350 ng/ml for protease II, and 500 ng/ml for protease III with a test volume of 0.05 m

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02239.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

The inactivation by EDTA of an extracellular protease, produced byStaphylococcus aureus, strain V8, was studied by the use of radioactive enzyme, gel chromatography and quantitative immunological methods. It was shown that the removal of Ca2+ from the enzyme by treatment with EDTA (5 mM) at 4° C resulted in irreversible loss of its activity on casein. This inactivation was not accompained by any measurable change in the molecular weight or immunoprecipitating properties of the protease. If treatment with EDTA were performed at 37° C, the loss of activity on casein would be followed by a subsequent loss of the immunoprecipitating properties of the enzyme, which was shown to be due to degradation of the enzyme. The degradation started after the loss of detectable enzyme activity. Thus it may be suggested that the removal of Ca2+ from the enzyme resulted in an altered tertiary structure of the protease in which the active site was hidden so that it could not reach the large substrate molecules i.e. casein and that, though inactive against casein, the calcium‐free enzyme was capable of degrading itself to peptides with molecular weights in the range 4,000–

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02240.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

The role of calcium in the production of an extracellular proteolytic enzyme (protease III) fromStaphylococcus aureus, strain V8 has been studied. No protease III was found in cultures grown in a casein hydrolysate medium containing EDTA at a concentration of 0.1 mM. Addition of Ca2+ during growth in this medium resulted in an accumulation of protease III in the culture. The appearance of protease was the result ofde novo proteinsynthesis. No inactive protease III could be detected in cultures grown in the presence of EDTA by electrophoresis in antibody containing agarose gels. However, protease III specific antibodies could be absorbed or blocked by supernatant fluids from cultures grown in the presence of EDTA, indicating that degradation products of the enzyme possessing antigenic determinants were present. It was concluded that calcium was neither necessary for synthesis nor for excretion of protease III but was required for the stability of the enzyme.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02241.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

DNA base composition (per cent GC) of thirteen coagulase‐negative staphylococci has been determined. The strains originate from urinary tract infection and include members both of the genusMicrococcusandStaphylococcusin the sense laid down by theSubcommittee on Taxonomy of Staphylococci and Micrococci.All strains were found to have a per cent GC in the range typical of staphylococci (30–40). It is concluded that this observation supports the proposal byBaird‐Parkerto place organisms of this type in the genusStaphyloc

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02242.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Vaccinia haemagglutinin was isolated from HeLa cells and purified by a two step ultra‐centrifugation procedure. In the first step the crude haemagglutinin was adjusted to 10 per cent sucrose and layered on top of 40 per cent sucrose. Fractions containing haemagglutinin were adjusted to 50 per cent sucrose, and 40 per cent sucrose was layered on top of this, The haemagglutinin which was recovered in the top fractions, contained no other proteins detectable by polyacrylamide electrophoresis and gave no precipitation line on double diffusion in agar against a vaccinia antiserum. The density range in sucrose was 1.08 to 1.18 g/cm3, indicating the lipoprotein nature of the materia

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02243.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Strains ofStaphylococcus aureusisolated from the nares of hares and mink were tested with the basic sets of human and bovine phages and with factor sera prepared against human staphylococci. Of 21 hare strains the 17 which belonged biochemically to the D biotype agglutinated strongly inh2factor serum and were lysed by group II phages. Four hare strains and all 108 mink strains, which belonged biochemically to the E (canine) biotype, were not lysed by the phages even at RTD X 1,000. Serologically the four hare strains (probably of canine origin) contained thea5antigen whereas only 17 per cent of the mink strains were typable, exhibiting weak reactions and no definite pattern.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1973.tb02244.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY