[A statistical method for the determination of the yield correlation of antibiotic-producing microorganisms].
The antibiotic yields of industrial selectants must be checked at several steps of cultivation. Here the question arises whether the activities at the different levels of cultivation are correlated. The common coefficient of correlation cannot be used because repeated determinations of the yield at one selectant result in different values. In order to have only one fixed value per selectant we define the mean value around which the observed values are varying. But these mean values cannot be observed. Thus, an adequate method of correlation similar to that in Guiard and Herrendörfer (1977) was used. The method is demonstrated in two examples: With selectants of Streptomyces noursei for streptothricin titers in 20 ml- and 20 l-cultures as well as with selectants of Penicillium chrysogenum for potency indices in surface cultures and penicillin titers in 50 ml submerged cultures, respectively. In both cases the coefficients of correlation were above 0.7.
Rapid screening for the isolation of mutants of Aspergillus nidulans with increased penicillin yields.
Summary. After UV treatment conidia of a strain of Aspergillus nidulans were plated on an agar medium. The survivors gave rise to individual colonies which were inoculated separately on agar discs and incubated. The discs were then transferred to biological assay plates seeded with spores of a strain of Bacillus subtilis sensitive to penicillin. Using this primary screening method, mutants have been isolated which, when tested later in shake flask cultures, gave larger penicillin yields than the parent strains.
Secoiridoids from Olea europaea
Abstract Three new secoiridoids have been isolated from the leaves of Olea europaea along with the previously reported. The compounds were identified by spectral means.