Abstract
The log phase cells of autolytic Micrococcus lysodeikticus (luteus) IFO 3333 did not autolyze when grown in the presence of trypsin although the growth curve and morphology of the cells were not influenced.
A non-autolytic mutant was obtained by subculture of the wild-type strain IFO 3333 on an agar slant containing 1% glucose. The mutant (strain MT) was arranged in tetrads or in clusters consisting of regular tetrads, in contrast to the wild-type IFO 3333 which occurred singly or in irregular masses. The mutant MT grown in a culture medium containing trypsin caused remarkable alteration in cell morphology : large cell packets consisting of a number of “unit tetrads” arranged regularly in three dimensions were formed by the addition of trypsin to the medium. The findings suggest that inhibition of the separation of divided cells is brought about by inactivation or suppression of a cell wall autolytic enzyme which plays an important role in the separation step and is accessible to externally added trypsin in the mutant cells but not in the wild-type cells.
The possibility that there are two kinds or phases of autolytic enzymes, “a physiological autolytic enzyme” and “a useless autolytic enzyme”, is discussed.
