Cell Fusion between Miura Strain and Takahashi Strain of Bacillus natto
Proof of Fusion by Plate-Count Method
1991 Volume 38 Issue 2 Pages 79-85
Details
1991 Volume 38 Issue 2 Pages 79-85
Cell fusion was examined using commercial Natto bacteria. An important point is the discrimination of fusants. Following results were obtained; (1) the optimum tonicity for protoplast regeneration (PR) of Bacillus was 0.2M, less than half as the ordinary methods, (2) PR is limited when amino acid-negative mutants were used because of the limitation of casamino acids (CA) content, and (3) an easy plate-count method, namely plating directly in hypertonic media, was possible. Based on above results, nucleic acid-negative mutants (NNM) not affected by CA, and a new protoplast reversion medium containing a low content of sodium succinate, a sufficient amount of CA and a little biotine as well as polyvinylpyrrolidone, were employed. The frequency of back mutation of NNM of Natto bacteria was 10-6 level by the Miura strain with an adenine marker and 10-5 level by the Takahashi strain with an uracil marker. Their PR occured efficiently by the easy plate-count method. The cell fusion between them was shown by giving five proofs in one series of experiments; protoplast formation, its reversion, check of back mutation, control number of fusion and fusant number. The fusion frequency was approximately 0.02%.
