Mating types of Job's tears smut fungus, Ustilago coicis, isolated in Japan were examined. The smut spores germinated to form a three- or four-celled promycelium on PDA medium generally and basidiospore (sporidium) was developed from each cell. Sporidia grew well by budding on PDA medium. On water agar medium, however, dikaryotic infection hyphae or parasitic mycelia were formed directly. Two sets of 8 monosporidial isolates from 2 smut spores were identified to have each two mating types on PDA medium and on the compatible pairing of the isolates, dikaryotic infection hyphae were developed on PDA 3 to 4 h after mixing in pairs. Pathogenicity of the isolates was also observed at compatible pairing, but not at incompatible pairing.

　The antifungal activity of benomyl (BEN) and thiabendazole (TBZ) was tested against five strains of Penicillium spp., two of which (96201Pe and 97203Pe) were isolated from mushroom factories where benzimidazole (BEN and/or TBZ) was used to disinfect the cultivation environment. BEN and TBZ were only slightly inhibitory to the growth of 96201Pe and 97203Pe. The minimum inhibitory concentration (MIC) of TBZ for the two strains was 10²-10⁴ times higher than those for the other strains. The two strains were identified as Penicillium crustosum.

　Max Delbrück, a theoretical physicist and the Nobel laureate in 1969 as a founder of molecular genetics, intensively studied the sensory physiology of Phycomyces. His transfer from physics to biology was first aroused by Niels Bohr, in connection with his speculations that the complementarity argument of quantum mechanics might have wide applications to other fields of scientific endeavor and especially in regard to the relations between physics and biology. Delbrück, however, failed to verify the existence of any complementarity paradox in his biological research results. We learnt from him the importance of teamwork, establishment of standard strains, and challenge spirit to new sciences throughout his research life.