[The action of selected herbicides on bacteriophages and Escherichia coli (author's transl)]

The effect of eight herbicides on the multiplication of bacteria and bacteriophages was tested with Escherichia coli, strains W1665F+ and C600, and with the RNA-phage M12 and the DNA-phage lambda in turbidimetric investigations and one-step growth experiments. E. coli is inhibited by seven of the herbicides investigated in concentrations of 10(-3)M, partly of 10(-4)M, too, and is promoted by some compounds in weaker concentrations. Naphthylacetic acid, (NES) largely independent of its concentration, causes increased density of bacteria in fluid culture. The multiplication of the M12 phage is inhibited in sometimes wide ranges of concentration by 2,4-D, MCPA, 2,4-DP, and CMPP but it is stimulated by NES and amitrole. The lambda-phage multiplication is inhibited only by CMPP, MCPA, MCPB, and phenylacetic acid interfere with the lysogenization of the bacteria and increase the lytic activity of the lambda-phages as 2,4-DP and NES do. 2,4-D strongly inhibits the plaque-forming ability of M12 phages already prior to their contact with the host cells, whereas MCPA and CMPP are inhibitory in the first phases and 2,4-DP in all phases of the phage replication. In the lambda-phage replication, too, CMPP is effective only in the first phases. Aspects of the mode of action of the herbicides in the procaryoute virus system are discussed.