Studies on Fungal Tannase

The possibility that selective inhibition of phage by antibiotic may be achieved by using bacterial mutant resistant to the antibiotic was investigated in the system of HM-phages of Clostridium saccharoperbutylacetonicum, a butanol-producing bacterium.

Consequently, it was found that Oxytetracycline, using the antibiotic-resistant mutant as host, inhibited selectively the growth of HM-phages. The bacterial mutant termed type A (one-step mutant resistant to 30 μg/ml of Oxytetracycline) did not permit the growth of HM-phages (HM 2 and HM 3) in the presence of the antibiotic (ca. 10 μg/ml), though it permitted the growth of the phages in the absence of the antibiotic.

An analysis of the mode of action of Oxytetracycline in HM 2-phage system revealed the following, (i) The antibiotic had a slight phagicidal action, (ii) It did not prevent the phage adsorption, (iii) It inhibited the protein synthesis in phage-infected cells, (iv) It inhibited the lysis of infected cells. Active phages were, however, not detected when the lysis-inhibited cells were artificially lysed.

Another type of bacterial mutant was also encountered. In this mutant termed type B the development of resistance to Oxytetracycline (30 μg/ml) was associated with a simultaneous loss of sensitivity to particular phages (HM 2 group).