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Biomedical subjects

R Murata

Publications and source records attributed to R Murata.

At least 145 records · Page 8Linked to original sources
PubMed1973

Role of zinc in the production of Clostridium perfringens alpha toxin.

Clostridium perfringens was found to produce alpha toxin in a synthetic medium containing zinc; in medium containing no zinc, a little toxin was detected in the early logarithmic phase of growth and it disappeared rapidly. No intracellular accumulation of alpha toxin protein occurred whether or not zinc was present in the medium. In zinc-deficient medium, the organisms produced and released into the surrounding medium the protein specifically precipitable with alpha antitoxin in an amount comparable to that of alpha toxin produced in the zinc-containing medium. The protein combined rapidly in some unknown way with zinc to form the active and stable alpha toxin.

Antitoxins↗
PubMed1971

International collaborative studies on the pertussis vaccine potency assay. Part played by the challenge in the mouse-protection test.

Because of wide variations in the methods used to assay the potency of pertussis vaccine, the effect of the type of challenge used in the mouse-protection test was studied. Eight laboratories took part in a collaborative investigation and the potencies of 4 pairs of vaccines were estimated. Two methods were used, a "local method" using local strains and procedures for challenge, and a "study method" using a distributed strain and a specified procedure. For both methods the challenge level (mouse LD(50)) and the number of colony-forming units per challenge dose varied greatly between laboratories.The results of the collaborative assay show that the use of a common challenge, Bordetella pertussis strain 18-323, and a uniform method for preparing the challenge did not reduce the heterogeneity of the results. Other factors influencing the results of potency assays, such as the use of different strains of mice and the effect of levels of challenge, have still to be investigated.

Animals↗