Rice grain structural characteristics of sake rice cultivar Hakutsurunishiki for daiginjo-shu brewing.

Hakutsurunishiki is a sake rice cultivar bred using Yamadabo (seed parent) and Wataribune 2 (pollen parent), equivalent to a Yamadanishiki sibling. This study evaluated the structural characteristics of the Hakutsurunishiki rice grain that contribute to the brewing characteristics of daiginjo-shu, via a comparison with Yamadanishiki. Hakutsurunishiki brown rice was a little heavy and had a large white core.

Artificial turn-on riboswitch to control target gene expression using a wild-type riboswitch splicing mechanism.

The thiamine pyrophospate (TPP)-dependent thiA riboswitch in Aspergillus oryzae regulates alternative mRNA splicing via TPP-riboswitch binding to reduce protein production. Based on the sequences involved in alternative splicing found in Neurospora crassa, we identified unique sequences that are thought to play a role in the alternative splicing of the thiA riboswitch. Based on the mechanism of alternative splicing regulated by the thiA riboswitch, we constructed a new TPP-dependent artificial riboswitch, which unlike the wild-type riboswitch, promotes, rather than inhibits, gene expression.

HAP-01, the first chromogenic substrate for Aspergillus oryzae acid protease.

The first chromogenic substrate for Aspergillus oryzae acid protease, 'HAP-01', was successfully developed after evaluating the substrate specificity of the enzyme. Furthermore, with HAP-01, digestion-triggered chromophore release was employed as a novel chromogenic technique.

Analyzing the relationship between the inorganic element profile of sake dilution water and dimethyl trisulfide formation using multi-element profiling.

Dimethyl trisulfide (DMTS) is the main component of hineka, an off-flavor generated in sake during storage. Genshu, or undiluted sake, is usually diluted with water during warimizu, the process of adjusting the alcohol content of sake. In this study, we evaluated how the inorganic element composition of sake dilution water affects the DMTS-producing potential of the sake (DMTS-pp, determined as the DMTS concentration in sake stored at 70°C for 1 week after dilution) using inductively coupled plasma-mass spectrometry (ICP-MS).

Construction of a thiamine pyrophosphate high-producing strain of Aspergillus oryzae by overexpression of three genes involved in thiamine biosynthesis.

We have found a gene (thiP) encoding thiamine pyrophosphokinase (TPK) in the Aspergillus oryzae genome. No riboswitch-like region was found in the upstream region of thiP, although it was repressed probably by thiamine pyrophosphate (TPP) as well as thiA and nmtA, which are strictly regulated by TPP-riboswitch sequence. To improve the productivity of TPP in A.

Molecular breeding of the Mureka-non-forming sake koji mold from Aspergillus oryzae by the disruption of the mreA gene.

Mureka-non-forming sake koji molds were constructed from an Aspergillus oryzae industrial strain by the disruption of the mreA gene using a host-vector system with the ptrA gene as a dominant selectable marker. All of the mreA gene disruptants obtained retained the advantages of the host strain in terms of the brewing characteristics, while their isoamyl alcohol oxidase (IAAOD) activities were significantly lower than that of the host strain. Sake brewing was successfully carried out using the koji prepared with the disruptants, followed by storage of the resultant non-pasteurized sake (nama-shu).

Roles of Mg2+ in TPP-dependent riboswitch.

We quantified the effect of Mg(2+) on thiamine pyrophosphate (TPP) binding to TPP-dependent thiA riboswitch RNA. The association constant of TPP binding to the riboswitch at 20 degrees C increased from 1.2 x 10(6) to 50 x 10(6) M(-1) as the Mg(2+) concentration increased from 0 to 1 mM.

Thiamine-regulated gene expression of Aspergillus oryzae thiA requires splicing of the intron containing a riboswitch-like domain in the 5'-UTR.

Exogenous thiamine regulates Aspergillus oryzae thiA, which is involved in thiamine synthesis. One of the two introns in its 5'-untranslated region (5'-UTR) contains motifs (regions A and B) highly conserved among fungal thiamine biosynthesis genes. Deletion of either region relieved the repression by thiamine and thiamine inhibited intron splicing, suggesting that regions A and B are required for efficient splicing.

Transformation of Aspergillus sp. and Trichoderma reesei using the pyrithiamine resistance gene (ptrA) of Aspergillus oryzae.

A pyrithiamine (PT) resistance gene (ptrA) was cloned from a PT resistant mutant of Aspergillus oryzae and was useful as a dominant selectable marker for transformation of all A. oryzae wild type strain as well as A. nidulans.