- Volume 135, Issue 1, 1989

Chitinase activity was measured in extracts of mycelial cells of Mucor rouxii as a function of the culture age. There was a peak of specific activity at the mid-exponential phase of growth (10 h), which paralleled chitin synthase activity. An additional peak of chitinase with higher specific activity was detected in 4 h cultures, which coincided with the onset of germination. Purification of chitinase activities from the cytoplasm revealed two enzymes, I and II, with different molecular mass and ionic charge. Antibodies induced with chitinase I did not cross-react with chitnase II. Both enzymes digested nascent chitin preferentially over preformed chitin, yielding diacetylchitobiose as the sole product of hydrolysis.

The character state data obtained for clusters defined in a previous phenetic classification were used to construct two probabilistic matrices for Streptomyces species. These superseded an original published identification matrix by exclusion of other genera and the inclusion of more Streptomyces species. Separate matrices were constructed for major and minor clusters. The minimum number of diagnostic characters for each matrix was selected by computer programs for determination of character separation indices (charsep) and a selection of group diagnostic properties (diachar). The resulting matrices consisted of 26 phena × 50 characters (major clusters) and 28 phena × 39 characters (minor clusters). Cluster overlap (overmat program) was small in both matrices. Identification scores were used to evaluate both matrices. The theoretically best scores for the most typical example of each cluster (mosttyp program) were all satisfactory. Input of test data for randomly selected cluster representatives resulted in correct identification with high scores. The major cluster matrix was shown to be practically sound by its application to 35 unknown soil isolates, 77% of which were clearly identified. The minor cluster matrix provides tentative probabilistic identifications as the small number of strains in each cluster reduces its ability to withstand test variation. A diagnostic table for single-membered clusters, constructed using the charsep and diachar programs, was also produced.