The depression of endolysin synthesis in bacteria infected with high multiplicities of phage λ

Abstract

The effect of multiplicity of infection was studied in Escherichia coli with lambda phage, using phage endolysin as an example of a late gene product. A very sensitive endolysin assay method was used so that the initiation time of endolysin synthesis could be more accurately determined. It was observed that high multiplicity of infection (1) increases the rate of lysogenization, (2) progressively delays lysis time, and (3) significantly delays and reduces the synthesis of endolysin in lamdacIII+ cII+ -infected cells. The extent of delay and reduction in endolysin synthesis increases with increasing multiplicity. In contrast, lamdacIII67cII68-infected cells show no delay in endolysin synthesis at high multiplicity of infection when compared with the lamdacIII+ cII+ -infected cells. The results suggest that (1) the expression of cIII and cII genes is multiplicity dependent, (2) high multiplicity of infection enhances the expression of the cIII and cII genes, and (3) the expression of the cIII and cII genes interferes with the expression of the late genes. A model to explain how the expression of the cIII and cII genes interferes with the expression of the late genes is proposed.

Effect of Multiplicity of Infection on Transcription in Escherichia coli Cells Infected by Bacteriophage Lambda

“…This reasonably explains the results shown in Fig. 1, 2, 4 and 5 as well as those reported earlier (Takeda, 1975;Court et al, 1975 ;Tsui & Mark, 1976). The late transcription (A-J-b2 region) is also repressed by increasing m.o.i, of cro ÷ phage (Fig.…”

“…The transcription results reported in this communication are consistent with the corresponding translation experiments reported previously (Court et al, 1975;Takeda, 1975;Tsui & Mark, 1976). Tsui & Mark (1976) found that the expression of both endonuclease and endolysin synthesis In explaining these observations, it was postulated that the cro gene product might be responsible. Results presented here confirm that, at high m.o.i., the cro gene product is responsible for the decrease in gene expression from both the left and right arms of the lambda genome.…”

“…Also, m.o.i, has a pronounced effect on the rate of [3H]thymidine incorporation in 2-infected cells (McMacken et al, 1970). We have also shown that some fl-galactosidase (large molecules) may leak out of host cells after 2 or T4 phage infection at very high m.o.i., but the leakage after 2 infection is much smaller than that after T4 infection (Tsui & Mark, 1976). …”

“…We have successfully used the lambda phage system, which has many advantages for gene dosage experiments, to demonstrate a good correlation between the number of genes present, or multiplicity of infection (m.o.i. ), and the extent of translation of a particular gene (Escherichia coli fl-galactosidase or phage endolysin) in the absence of negative controlling factors (Tsui & Mark, 1976;Luk & Mark, 1980, 1982.…”

Cloning and characterization of bacteriophage-like DNA from Haemophilus somnus homologous to phages P2 and HP1

“…Lysozyme activity was assayed in a procedure adapted from Tsui and Mark (67). Substrate cells (JM105) were grown in 100 ml of LB broth to an A 600 of 1.0, pelleted by low-speed centrifugation, and resuspended in an equal volume of 0.1 M EDTA (pH 8).…”