Plasmid-dependent inhibition of growth of bacteriophage T4 ndd mutants.

Mutants of bacteriophage T4 that fail to induce nuclear disruption (ndd mutants) are unable to grow in the wild-type Escherichia coli strain CT447. This inhibition of the growth of ndd mutants occurs only in the presence of a large (ca. 80-megadalton) plasmid resident in CT447 cells.     

Intrinsic Protein Fluorescence Interferes with Detection of Tear Glycoproteins in SDS-Polyacrylamide Gels Using Extrinsic Fluorescent Dyes

Intrinsic protein fluorescence may interfere with the visualization of proteins after SDS-polyacrylamide electrophoresis. In an attempt to analyze tear glycoproteins in gels, we ran tear samples and stained the proteins with a glycoprotein-specific fluorescent dye. The fluorescence detected was not limited to glycoproteins. There was strong intrinsic fluorescence of proteins normally found in tears after soaking the gels in 40% methanol plus 1-10% acetic acid and, to a lesser extent, in methanol or acetic acid alone. Nanograms of proteins gave visible native fluorescence and interfere with extrinsic fluorescent dye detection. Poly-L-lysine, which does not contain intrinsically fluorescent amino acids, did not fluoresce.     

Protein induced by bacteriophage T4 which is absent in Escherichia coli infected with nuclear disruption-deficient phage mutants.

A protein induced by wild-type T4 phage which is absent in Escherichia coli infected with nuclear disruption-deficient phage (with mutations in gene ndd) was identified by polacrylamide gel electrophoresis. This protein was synthesized at maximum rate at 3 to 6 min after infection. It had a molecular weight of 15,000 determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was associated with sedimentable fractions of the cell from which it can be dissociated with 1 M guanidine-hydrochloride. The dissociated protein can be partly recovered in a form soluble in dilute buffer after partial purification and dialysis. The occurrence of this protein in a particulate cell fraction is of interest because of the postulated role of the bacterial cell membrane in nuclear disruption.     

Nuclear Disruption After Infection of Escherichia coli with a Bacteriophage T4 Mutant Unable to Induce Endonuclease II

Nuclear disruption after infection of Escherichia coli with a bacteriophage T4 mutant deficient in the ability to induce endonuclease II indicates that either (i) the endonuclease II-catalyzed reaction is not the first step in host deoxyribonucleic acid (DNA) breakdown or (ii) nuclear disruption is independent of nucleolytic cleavage of the host chromosome. M-band analysis demonstrates that the host DNA remains membrane-bound after infection with either an endonuclease II-deficient mutant or T4 phage ghosts.     

Genetic Location of a Mutant of Bacteriophage T4 Deficient in the Ability to Induce Endonuclease II

Reciprocal three-factor crosses and the use of a partial revertant of a putative ribonucleotide reductase mutant of Escherichia coli B/5 as indicator have made it possible to map denA (deficient in endonuclease II) between nrd-11 (ribonucleotide reductase gene B) and amM69 (gene 63) on the bacteriophage T4 chromosome.