Shigeru Oita

Binding of Barley and Wheat α-Thionins to Polysaccharides

An antimicrobial peptide termed BCP-2 was purified from barley grain by chitin-affinity treatment and HPLC. The results of amino acid analysis and mass spectrometry of BCP-2 indicate that the peptide is very similar to barley α-thionin. BCP-2 and wheat α1-thionin were also bound to β-glucan but not to starch. The binding of BCP-2 to laminarin (β-1,3-1,6-glucan) and laminarioligosaccharides was supported by fluorescence polarization data. This is the first report on the binding of α-thionins to polysaccharide containing chitin and β-1,3-glucan, which construct fungal cell walls.

Purification and Properties of a New Chitin-binding Antifungal CB-1 from Bacillus licheniformis

CB-1, a new antifungal, was purified from Bacillus licheniformis. The molecular mass of CB-1 was estimated as 42 kDa by gel filtration column chromatography. CB-1 seemed to be an aggregation product from 4 kinds of peptides. CB-1 contained 10 amino acids and some fatty acids of C14-18:0 and C18:1. CB-1 irreversively bound with chitin powder.

Flutolanil Resistance as a Genetic Marker of Coprinus cinereus Strains

All 4 Schizophyllum commune strains among several basidiomycete species were exclusively resistant to flutolanil, which inhibits succinate dehydrogenase complex (SDC) function. Flutolanil resistant strains could be screened from monokaryotic protoplasts of sensitive Coprinus cinereus, by treating them with a cloned genomic SDC iron-sulfur protein (IP) gene from the resistant S. commune. The obtained resistance was stably transferred to the progeny.

Identification and overexpression of genes encoding cAMP-dependent protein kinase catalytic subunits in homobasidiomycete Schizophyllum commune.

This report describes the first cloning and overexpression experiments on genes encoding cAMP-dependent protein kinase catalytic subunits in homobasidiomycete Schizophyllum commune. We used a degenerate PCR approach to identify two novel genes (ScPKAC1 and ScPKAC2) that are very similar to the catalytic subunits in many eukaryotes. The morphological phenotypes of ScPKAC1 and ScPKAC2 overexpressing clones were compared with those of constitutively active ScGP-A overexpressing clones to determine whether ScPKAC1 and ScPKAC2 are located downstream of heterotrimeric G-protein alpha subunit ScGP-A. Overexpression of constitutively active ScGP-A increased intracellular cAMP levels and suppressed aerial mycelium formation. In contrast, overexpressing ScPKAC1 and ScPKAC2 did not affect the intracellular cAMP levels, though aerial mycelium formation was strongly suppressed. These observations suggest that ScPKAC1 and ScPKAC2 proteins are located downstream of the G-protein alpha subunit ScGP-A in the cAMP signaling pathway.