- Volume 92, Issue 1, 1976

Summary: Penicillium stoloniferum nrrl5267 contains two electrophoretically distinct viruses (PsV-F and PsV-S). An in vivo system was developed to test whether a number of fungal metabolites had antiviral properties on PsV-F replication in P. stoloniferum. Preliminary results indicated that the mycotoxin patulin can block mycovirus replication. Portions of 48 h mycelium were incubated in the presence of varying levels of patulin, and after an additional 48 h incubation, PsV-F content was measured in E 260 units by polyacrylamide gel electrophoresis. Patulin at 11, 16 and 20 μg/mg dry wt mycelia blocked PsV-F replication 26, 61 and 71 %, respectively, compared with untreated controls. At these levels, host biomass RNA and protein synthesis were minimally affected. Non-proliferating fungal mycelium is capable of continued support of PsV-F replication, which is sensitive to patulin. Apparently, inhibitory doses of patulin stimulated PsV-S replication during this 48 h incubation. The preferential action of patulin may arise from metabolite binding to functional enzymes required for virus replication.

Summary: The methyl esters of free mycolic acids from representative strains of Nocardia asteroides, N. brasiliensis, N. caviae and the ‘rhodochrous’ complex were subjected to detailed mass spectral analysis. The anhydromycolic esters of the Nocardia strains consisted of homologous series containing from zero to three double bonds, with the main components of the parent mycolic acids centred on C52 to C54 (range C46 to C58). The anhydromycolates from one rhodochrous strain, Nocardia opaca, had a molecular weight range similar to the nocardiae (C46 to C57) but the remaining rhodochrous strains gave an homologous series of anhydromycolates containing from zero to two double bonds, with the main components of the parent mycolic acids centred on C38, C42, C44 or C46 (total range from C34 to C50). The mycolic acids from the rhodochrous strains with chain lengths centred around C40 form a group intermediate in size between corynomycolic acids (centred around C50) and nocardomycolic acids (centred around C50). These data weaken the case for retaining the ‘rhodochrous’ complex in the genus Mycobacterium, and also show that many rhodochrous strains can be distinguished from true nocardiae and corynebacteria. These results confirm the value of lipid characters in the classification of these organisms.