The protein concentration of crude cell and tissue extracts as estimated by the method of dye binding: Comparison with the lowry method

✦ Synopsis

The protein concentration of crude extracts from cultured cells and of subcellular fractions from rat tissues has been estimated both by the method of Bradford, involving the binding of Coomassie brilliant blue G-250, and by the procedure of Lowry ef al. with the same preparation of bovine serum albumin as a common protein standard. Whereas the method of dye binding yielded significantly lower values than did the Lowry procedure, a consistent quantitative relationship existed between the values obtained by the two techniques. Evidence is provided that this discrepancy does not result from the presence in such complex biological mixtures of a class of small peptides, undetected by the method of dye binding, that react with the Lowry reagents.

Acute and Chronic Toxicity of Veratrum V

Acute and Chronic Toxicity of Veratrum Viride††The Veratrum viride studied was the whole-powdered drug marketed by Irwin, Neisler & Co. under the name, Vertavis. The work reported herein was supported by a grant from this firm. The batch of powder used in these experiments was stated by the manufacturer to have been assayed biologically by the Craw method on Daphnia magna. One Craw unit of the material studied was stated to be 15.6mg. With regard to this assay, Mr. R. O. Craw has been so kind as to allow us to publish a brief explanation: A reference lot of Yerolrum oirid; powder was set-aside as a standard and a 10% w/v aqueous extract was made of this powder. The average median length of life in 50 assays of 1000 daphnia on immersion in the solution was determined to be 2.22 hours. The daphnia were considered dead when the heart was found to be in systolic standstill on microscopic examination. Succeeding lots of powder were assayed and their potency determined by relating the median length of life of daphnia to 2.22 hours, which is one unit. Twenty assays of 10 animals each were used on each lot of powder.‡‡The authors wish to thank Dr. J. F. A.,McManus of the Department of Pathology for a pathologic report on the tissues, and Mr. James Thomas and Mrs. Bobby E. Teague for technical assistance.

✍ Perdue, Adoline S. ;Bell, Frances ;Starnes, W.R. ;Hitchcock, Philip ;Teague, R.S 📂 Article 📅 1950 🏛 Elsevier ⚖ 346 KB 👁 1 views