New role of a histone chaperone, HirA: Involvement in kojic acid production associated with culture conditions in Aspergillusoryzae.

Kojic acid (KA) is a representative secondary metabolite of Aspergillus oryzae, but the underlying molecular mechanisms that regulate KA production are unknown. This study tried to find a genetic factor of KA production in A. oryzae, with a special focus on liquid cultures.

Novel glucoamylase-resistant gluco-oligosaccharides with adjacent α-1, 6 branches at the non-reducing end discovered in Japanese rice wine, sake.

Sake, a traditional Japanese rice wine, contains various oligosaccharides (Sake oligosaccharides; SAOs) derived from rice starch. We previously found that SAOs reach a high degree of polymerization (DP). In this study, we developed a hydrophilic interaction liquid chromatography-time-of-flight/mass spectrometry (HILIC-TOF/MS) based analytical method to separate isomeric SAOs.

Transglycosylation Forms Novel Glycoside Ethyl α-Maltoside and Ethyl α-Isomaltoside in Sake during the Brewing Process by α-Glucosidase A of .

Sake, the Japanese rice wine, contains a variety of oligosaccharides and glucosides produced by fungal enzymes during the brewing process. This study investigates the effect of knocking out the α-glucosidase () gene on the transglycosylation products in brewed sake. In addition to α-ethyl glucoside and α-glyceryl glucoside, the amount of two compounds that have molecular mass values similar to that of ethyl maltose decreased by gene knockout.

Effect of the Air/Water Interfacial Properties of Amine Derivatives on the in Situ Fabrication of Microsized Gold Sheets.

Development of new methods for producing large-area nanocrystals with specific shapes is crucial for advancements in various fields. In this study, submillimeter-sized sheet-structured gold crystals with nanoscale thicknesses were fabricated by chemical reduction of HAuCl in the presence of long-chain amidoamine-derived surfactants (C nAOH; n = 12, 14, 16, or 18) in aqueous solutions. Using the C18AOH system at 30 °C, large-area sheet-structured crystals with widths of ∼100 μm and thicknesses of 30 nm were effectively obtained at the air/water interface.

Analysis of the oligosaccharides in Japanese rice wine, sake, by hydrophilic interaction liquid chromatography-time-of-flight/mass spectrometry.

A traditional Japanese alcoholic beverage, sake, contains several oligosaccharides, which are associated with the taste of sake; however, little is known about the specific molecular species and concentrations of oligosaccharides in sake. Here, we developed an analytical method using hydrophilic interaction liquid chromatography-time-of-flight/mass spectrometry (HILIC-TOF/MS) which successfully detects the oligosaccharides in sake. A series of oligosaccharides with successive degree of polymerization (DP) values up to 18 were identified in sake for the first time, which we have named sake oligosaccharides (SAOs).

Stimuli-Responsive Extraction and Ambidextrous Redispersion of Zwitterionic Amphiphile-Capped Silver Nanoparticles.

Citrate-stabilized silver nanoparticles (AgNPs) were functionalized with a pH-responsive amphiphile, 3-[(2-carboxy-ethyl)-hexadecyl-amino]-propionic acid (C16CA). At pH ∼ 4, the zwitterionic C16CA assembled into lamellar structures due to the protonation of the amine groups of the amphiphile that neutralized the anionic charge of the carboxylate groups. The lamellar supramolecules incorporated the AgNPs into their 3D network and extracted them from water.

Cyclopiazonic acid biosynthesis gene cluster gene cpaM is required for speradine A biosynthesis.

Speradine A is a derivative of cyclopiazonic acid (CPA) found in culture of an Aspergillus tamarii isolate. Heterologous expression of a predicted methyltransferase gene, cpaM, in the cpa biosynthesis gene cluster of A. tamarii resulted in the speradine A production in a 2-oxoCPA producing A.

Recovery and redispersion of gold nanoparticles using the self-assembly of a pH sensitive zwitterionic amphiphile.

The pH-responsive self-assembly of zwitterionic amphiphile C16CA was expanded to the recovery of gold (Au) nanoparticles for environmentally friendly chemistry applications. Multilayered lamellae at pH ∼ 4 were successfully incorporated into nanoparticles by dispersion. Redispersion of nanoparticles was achieved under basic conditions by the transition of self-assembly.

Stabilities of crystal faces of aragonite (CaCO3) compared by atomic force microscopic observation of facet formation processes in aqueous acetic acid.

Crystal faces of aragonite in various orientations were dissolved in water or in a dilute aqueous acetic acid. Facet formation processes were observed in situ using atomic force microscopy (AFM). At the polar (001) surface, which gave atom-resolved AFM images in air, less polar {112} facets were developed in water.