Epididymal metastasis from prostatic carcinoma.

A case of epididymal metastasis from carcinoma of the prostate with an unusual presentation is reported. A review of the literature disclosed only 10 reported cases of this rare finding. A mechanism for the method of metastasis in this patient is proposed.

Bacteriophage T4 RNA ligase: preparation of a physically homogeneous, nuclease-free enzyme from hyperproducing infected cells.

Infection of Escherichia coli by a bacteriophage T4 regA, gene 44 double mutant leads to about a 7-fold increase in the amount of RNA ligase obtained after infection by wild-type phage. Using cells infected by the double mutant, RNA ligase was purified to homogeneity with a 20% yield. Unlike previous preparations of this enzyme, the ligase is free of contaminating nuclease and is therefore suitable for intermolecular ligation of DNA substrates.

Bacteriophage T4 RNA ligase is gene 63 product, the protein that promotes tail fiber attachment to the baseplate.

RNA ligase and tail fiber attachment activities, normally induced following bacteriophage T4 infection of Escherichia coli, are not induced when gene 63 amber mutants of T4 infect nonpermissive host cells. Both activities are induced when these mutants infect permissive hosts, or when revertants of these mutants infect nonpermissive hosts. When one of these mutants infects a host that carries supF, both activities are more than normally heat labile.