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Studies on Pneumococcal Polysaccharide
[摘要] Biosynthesis of C14-SI is easily accomplished by the addition of C14-glucose to the culture medium in which the pneumococci are grown. Approximately 4.5 per cent of the radioactivity thus introduced into the medium is present in the purified C14-SI. Introduction of 100 μc of C14-glucose per liter of culture medium is sufficient to adequately label SI for identification in animal tissue extracts when the dosage is 500 μg per mouse. If smaller antigenic dosages are to be used additional C14-glucose would probably be required for adequate labeling if the counting technique described is to be used.Significant comparative counts due to C14-SI can be secured on splenic tissue extracts by making the determinations on material in water solution if the dosage approximates 500 μg per mouse. This method permits use of extracts for antigenic assay or other biological procedures not possible when the sample is destroyed as in the barium carbonate method of determining total radioactivity. Results obtained by this counting technic are comparative only but are proportional to the concentration of C14-SI present in the sample.
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[效力级别]  [学科分类] 生物科学(综合)
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