IT HAPPENED THIS MONTH... a glance at yesterday
in relation to today
IN AUGUST—(1881)—at the fourth annual meeting of the American Society of Microscopists, Dr. Jacob Redding of Falmouth, Indiana takes issue with the belief that muscular contraction is due to changes in non-living formed material and is not dependent upon bioplasm. He cites considerable histological evidence to show that "every muscular contraction is directly dependent on active and forcible changes taking place in confined bioplasm." x Today we know that the energy required for muscular contraction is obtained through generation of ATP in muscle "bioplasm." It is not necessary to expend much effort to obtain high quality ATP. Schwarz BioResearch supplies this and related compounds, both unlabelled and labelled in various positions with C1Jt or Pi2. Simply consult our catalog for the compound you need. IN AUGUST—(1912) — there is reported'an improved method for the determination of tyrosine in protein. Folin and Denis 2 show that the gravimetric separation of tyrosine from protein hydrolysis products is not quantitative. They have developed a procedure which involves a 12-hour digestion in acid followed by development of a blue color with a phosphotungstic-phosphomolybdic reagent. Results are consistently higher than those obtained with the gravimetric methods used in the past. Modifications of this colorimetric method are still widely used in research, clinical and industrial control laboratories. If you are analyzing for tyrosine or other amino acids, Schwarz can provide you with convenient, reliable primary standards. The Schwarz Kit of 18 optically standardized natural amino acids is suitable for the most precise research or industrial purposes. Add it to your stock of basic biochemicals. IN AUGUST—(1943) — the Archives of Biochemistry carries a paper by LaufTer and Stanley describing the effects of urea upon tobacco mosaic virus. Neutral 6M urea solutions disintegrate high molecular weight virus nucleoprotein particles into much smaller fragments. Phosphorus analyses indicate that nucleic acid is split away from protein. Much of the virus infectivity is lost. The considerable reduction in the specific infectivity of residual high molecular weight nucleoprotein indicates that inactivation may take place before the molecule is extensively disintegrated. 3 Nucleic acid chemistry continues to play a prominent role in modern virus research. Schwarz BioResearch has long been a leading supplier of all types of nucleic acid compounds to virologists — purines, pyrimidines, nucleosides, nucleotides, and nucleic acids, plain and radiolabeled. Write for our latest catalog and price list. 1. Redding, J . : Muscular contractility. Proc. Am. Soc. Microscopists, (August) 1881, p. 17. 2. Folin, O., ami Denis, W. : Tyrosine in proteins as determined by a new colorimetric method, J. Biol. Chem. 12:2X5 (Aug.) 1912. 3. Lauffer, M. A., and Stanley, W. M. : The denaturation of tobacco mosaic virus by urea. I. Biochemical aspects. Arch. Biochem. 2:413 (Aug.) 1943.
S C H W A R Z B I O R E S E A R C H , I N C . • Dept. 8A • Mount Vernon, New York BIOCHEMICALS • RADIOCHEMICALS • PHARMACEUTICALS jor research,
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