Fragment Sizes Produced from T5 Bacteriophage DNA Molecules by Acid Deoxyribonuclease

The action of acid deoxyribonuclease on T5 bacteriophage DNA results in a "random distribution" of sizes of duplex fragments as judged by electron microscopy. No preferred subunit size resulting from the "single hit" action can be detected down to lengths of 0.1 micron or less. The results are in agreement with the coexistence of a "single-hit" and a "double-hit" kinetics.

Biochemical Tests Indicative of Reaction of Castor Bean to Botrytis

Pectic and cellulolytic enzymes caused browning and maceration of capsules of susceptible varieties of castor bean but not of resistant varieties. Results of tests in which pericarp tissue of the capsule was treated with vanillin and H(2)SO(4) and with an aqueous solution of FeCl(3) and K(3)Fe(CN)(6) showed that resistance to the hydrolytic enzymes was correlated with both a low concentration of flavanols and related compounds and the presence of oxidized compounds in injured tissue. Resistance appeared to be due to inactivation of pectic, cellulolytic, and other hydrolytic enzymes by oxidation products of phenolic compounds. The biochemical tests made rapid measurement of resistance possible.