Shodo Hara

Construction of a fusion gene comprising the Taka-amylase A promoter and the Escherichia coli β-glucuronidase gene and analysis of its expression in Aspergillus oryzae

SummaryNorthern blot analysis of glucose-grown and starch-grown mycelia of Aspergillus oryzae R11340 was conducted using the cloned Taka-amylase A (TAA) gene as a probe. The amount of mRNA homologous to the TAA gene was increased when this fungus was grown with starch as a sole carbon source. In order to analyze the induction mechanism, we inserted the Escherichia coli uidA gene encoding β-glucuronidase (GUS) downstream of the TAA promoter and introduced the resultant fusion gene into the A. oryzae genome. Production of a functional GUS protein was induced by starch, but not by glucose. When the effects of various sugars on expression of the fusion gene were examined, the results suggested that the expression of the fusion gene was under control of the TAA gene promoter.

Genetic transfer applied to traditional sake brewing.

Outline of sake brewing. Breeding of killer sake yeasts. Breeding of useful sake yeasts by gene disruption. Molecular approaches for breeding of Koji-mould, Aspergillus oryzae

Cloning and nucleotide sequence of the genomic ribonuclease T2 gene (rntB) from Aspergillus oryzae

SummaryUsing synthetic oligonucleotide probes, we have cloned a genomic DNA sequence encoding a ribonuclease (RNase) T2 gene (rntB) from Aspergillus oryzae on a 4.8 kb HindIII fragment. DNA sequence analysis of the RNase T2 revealed the following: (1) The gene is arranged as five exons and four introns; (2) The deduced amino acid sequence contains 239 amino acid residues of the mature enzyme. In addition, there exist 17 amino acid residues thought to be a signal peptide sequence at the N-terminus and 20 amino acid residues at the C-terminus; (3) The nucleotide sequence of the rntB gene is homologous to those of the RNase Rh gene from Rhizopus niveus and the S2 stylar glycoprotein gene of Nicotiana alata with degree of about 51% and 47%, respectively; (4) A. oryzae and A. nidulans transformed with the cloned rntB gene had much higher ribonuclease T2 activity than wild-type strains.

A Fundamental Study on the Semi-continuous Wine Making

甲州種ブドウ果汁を用いて, 三槽式回分法により半連続醸造を検討した。各槽の液量8l, 4l/day, 平均滞留時間2日, 醗酵温度20℃, 初発果汁糖濃度21%, SO250PPmの条件で, 2週間の経過では安定した醗酵が示された。一方, 上田氏の連続化の図式解法を用いて検討した所, 実験値とよく一致したので, 連続化の可能性を認めた。