DNA fingerprints of chickens selected for high and low body weight for 31 generations

Two lines of White Plymouth Rock chickens that have been divergently selected for 8-week body weight for 31 generations were compared for patterns of DNA fingerprints (DFP). Digestion of DNA with HinfI and hybridization to Jeffreys' minisatellite probe 33.6 resulted in DFPs that were relatively similar within lines (bandsharing = 0.50) and less similar between lines (bandsharing = 0.22). Analyses of scorable DFP bands produced by mixing DNA from individuals within lines indicated that 48% were line-specific. Causes for the differences in DFP patterns between lines and for occurrence of line-specific bands for the two lines divergently selected for body weight are discussed.     

Correlation of intralesional in vivo chemotherapy of line 10 hepatoma with in vitro drug sensitivity

The effects of intralesional chemotherapy with 7 different drugs on line 10 hepatoma grown in strain 2 guinea pigs were compared with the sensitivity of line 10 tumor cells in vitro, using a micro modification of the tumor stem assay with capillary tubes. A modified method was used to evaluate the in vitro dose-response curves. The correlation for in vivo/in vitro resistance was found to be 100% and for in vivo/in sensitivity it was 80%.     

Synchronous digestion of SV40 DNA by exonuclease III.

We have established an optimal condition for the synchronous digestion of SV40 DNA with Escherichia coli exonuclease III. Electron microscopy and polyacrylamide gel electrophoresis were used to obtain accurate measurements on the lengths of DNA before and after exonuclease III digestion. Based on this finding, a new method for determining the sequence of long duplex DNA can be realized. It involves (a) the synchronous digestion of the DNA from the 3' ends with exonuclease III, followed by (b) repair synthesis with labeled nucleotides and DNA polymerase, and (c) sequence analysis of the repaired DNA.     

Microbiology of saturated salt solutions and other harsh environments: v. Relation of inosine-5'-phosphate and carbohydrate to growth of wildtype and mutant penicillium in boric Acid and potassium chloride selective media

The study of chemical stress tolerance in a Penicillium mutant was continued using KCl- and H(3) BO(3) -saturated glucose peptone broth as a basic growth medium. Growth was completely restricted to the mutant. Variations were the presence or absence of inosine-5'-phosphate (inosinic acid, IMP) and choice of carhohydrate which was substituted for glucose. All six monosaccharides used-three hexoses, three pentoses - were essentially equivalent hence data are presented only for D-glucose and D-xylose. The other carbohydrates, sucrose, lactose, maltose and starch differed in their suitability as carbon sources. In the presence of the nionosaccharides the mutant can grow both in KCl and H(3) BO(3) media, but growth rates are greatly enhanced by IMP. Boric acid blocked sporulation under all conditions. KCl permitted spores of abnormal color to form without IMP, whereas spores of normal green color appeared in its presence. Media containing H(3) BO(3) and disaccharides or starch supported no growth, but addition of IMP stimulated growth without sporulation. In KCl media sucrose alone among the disaccharides and starch permit limited growth without IMP, but the nucleotide is required for sporogenesis. These results show that the role of nucleotides, especially IMP, is not limited to recovery from exposure to extreme salt effects, but also applies to growth in the continuing presence of quite different chemical stress conditions.