Growth of Elements of Various Sizes Found in Cultures of a Stable Proteus L Form

Abstract

Samples of a liquid culture of Proteus L9 were transferred to agar blocks containing the same medium as the liquid culture. Photmicrographs were made of the slide cultures thus obtained, and the diameters of a large number of individual L elements determined. The measurements indicated that the elements of the L cultures studied could be assigned to two classes (I and II) with regard to their size. The elements of class I had an average diameter of 0.33[mu] (standard deviation 0.071; standard error of the mean 0.006[mu]); the corresponding figures for class II were 0.94, 0.21 and 0.02[mu], respectively. The growth of individual L elements in the slide cultures was followed during incubation at 30[degree]. Only elements having a diameter > 0.6 to 0.7[mu], i.e. elements belonging to class II, enlarged measurably or formed microcolonies. Calculations based on measurements made on L elements growing on streak plates confirmed these observations.