Interfacial biosilica coating of chitosan gel using fusion silicatein to fabricate robust hybrid material for biomolecular applications.

An enzyme-encapsulated silica-based hybrid material was developed using a chitosan gel. Fusion silicatein (InaKC-ChBD-Sil), silicatein fused with a soluble tag and chitin-binding domain, was employed as an interfacial catalyst to form silica on a chitosan gel matrix under physiological conditions, and horseradish peroxidase was immobilised on the hybrid material. Silica formation on the gel was verified via fluorescence microscopy using a designed fusion protein called TBP-mCherry, a fluorescent protein fused with a silica-binding peptide. We report a chitosan gel-silica hybrid material capable of encapsulating enzymes for biomedical and environmental applications.

Differential diagnosis between calcifying odontogenic cyst and adenomatoid odontogenic tumor by computed tomography images.

OBJECTIVES: Calcifying odontogenic cysts (COC) and adenomatoid odontogenic tumors (AOT) have similar radiographic findings. We examined the radiographic and computed tomography (CT) images of patients histologically diagnosed with COC or AOT and identified their characteristic findings. METHODS: The subjects included 12 patients histologically diagnosed with COC or AOT (one female and five males per group), who underwent CT at our hospital between Nov 1998 and Jun 2019. The location of the lesion, impacted tooth, bone expansion, root resorption, tooth migration, calcified body, and presence or absence of a high-intensity zone in the marginal area of the lesion were examined. RESULTS: In patients with COC, five patients with COC exhibited bone expansion toward the buccal side. The lesion encompassing the crown was attached to the cement-enamel junction and contained a radiopaque lesion with a calcified body. In 6 patients with COC, irregularly shaped calcified bodies were observed with small tooth-like structures. In patients with AOT, all six patients with AOT exhibited bone expansion toward the buccal and lingual sides. The lesion encompasses a part of the tooth root or the entire tooth. Punctate calcification was observed within the lesion and the marginal area in three patients, and a high-intensity zone was observed in the marginal area of the lesion in two patients. CONCLUSION: We report imaging findings that may be characteristic of COC and AOT, suggesting that CT findings may be useful for differentiating between COC and AOT.

Roles of Microbial Activity and Anthraquinone-2,7-disulfonate as a Model of Humic Substances in Leaching of Iron from Hematite into Seawater.

Fertilization with a mixture of steelmaking slag and compost can affect the supply of dissolved iron used to restore seaweed beds, however, the mechanisms of iron elution from the fertilizer are not well understood. In the present study, the microorganism was isolated from Fe-fertilizer incubated in coastal seawater for 6 months, and was identified as Exiguobacterium oxidotolerans by 16S rDNA sequencing. The iron elutability of the bacteria was proved based on the increasing of dissolved iron by incubation with Fe2O3 (hematite) under a seawater-like condition. The value of ORP was changed by inoculated of the bacteria from ca. 0 to ca. -400 mV, which is anticipated concerning to reduction of Fe. The concentration of eluted iron was largely depended on those of organic acids produced by bacteria. From the results, it was proved that E. oxidotolerans is capable of Fe reductive eluting of iron from Fe2O3 into seawater. Anthraquinone-2,7-disulfonate (AQDS), which can play as an electron acceptor/donor between microbe and insoluble Fe2O3 particles, enhanced the effect of iron bio-leaching.

Simultaneous production of high quality biodiesel and glycerin from Jatropha oil using ion-exchange resins as catalysts and adsorbent.

The simultaneous production of high quality biodiesel and glycerin was realized by a bench-scale process using expanded-bed reactors packed with cation- and anion-exchange resins. The mixed-solution of crude Jatropha oil and methanol at a stoichiometric molar ratio was supplied to the process. The free fatty acid as well as triglyceride was completely converted to biodiesel. All by-products were adsorbed on the resin and the effluent from the process was free from them. The effluent fully met the international biodiesel standard specifications without any downstream purification processes except for removing methanol. The glycerin adsorbed on the resin was completely recovered as a transparent methanol solution during regeneration of the resin.

Production of biodiesel from plant oil hydrolysates using an Aspergillus oryzae whole-cell biocatalyst highly expressing Candida antarctica lipase B.

For enzymatic biodiesel production from plant oil hydrolysates, an Aspergillus oryzae whole-cell biocatalyst that expresses Candida antarctica lipase B (r-CALB) with high esterification activity was developed. Each of soybean and palm oils was hydrolyzed using Candida rugosa lipase, and the resultant hydrolysates were subjected to esterification where immobilized r-CALB was used as a catalyst. In esterification, r-CALB afforded a methyl ester content of more than 90% after 6 h with the addition of 1.5 M equivalents of methanol. Favorably, stepwise additions of methanol and a little water were unnecessary for maintaining the lipase stability of r-CALB during esterification. During long-term esterification in a rotator, r-CALB can be recycled for 20 cycles without a significant loss of lipase activity, resulting in a methyl ester content of more than 90% even after the 20th batch. Therefore, the presented reaction system using r-CALB shows promise for biodiesel production from plant oil hydrolysates.

Proteinase-mediated drastic morphological change of peptide-amphiphile to induce supramolecular hydrogelation.

We report a novel peptide-amphiphile having a simple molecular structure that can gelate an aqueous solution at a remarkably low concentration and can be designed to be responsive to a disease-related enzyme by undergoing a drastic morphological change.

Homogeneous enzymatic reactions in ionic liquids with poly(ethylene glycol)-modified subtilisin.

Subtilisin Carlsberg was covalently modified with comb-shaped poly(ethylene glycol) (PM13). PM13-modified subtilisin (PM13-Sub) was readily solubilized in three different ionic liquids (ILs), i.e., [Emim][Tf2N], [C2OC1mim][Tf2N] and [C2OHmim][Tf2N]. Analysis of homogeneous enzymatic reactions in the ILs revealed that PM13-Sub exhibited excellent catalytic performance while the native enzyme suspended in ILs showed no activity. Hydrophobicity of ILs slightly affected enzyme activity, and the relatively hydrophobic IL [Emim][Tf2N] was the preferred medium for enzymatic reactions, similar to enzymatic reactions in conventional organic solvents. Enzyme activity was much higher in [Emim][Tf2N] than in conventional organic solvents, and excellent activity was associated with unique properties of ILs such as hydrophobicity and high polarity. Furthermore, PM13-Sub showed good stability in [Emim][Tf2N], and maintained 80% of its initial activity after 60 h.

Crown ether-mediated extraction and functional conversion of cytochrome C in ionic liquids.

We report that a macrocyclic ligand enables transfer of a protein from an aqueous phase to ionic liquids. The extraction behavior of heme protein cytochrome c (Cyt-c) from an aqueous phase into ionic liquids was investigated with crown ethers. A hydroxyl-group-containing ionic liquid with dicyclohexano-18-crown-6 was found to be capable of quantitative partitioning of Cyt-c, whereas the protein transfer using conventional organic solvents was negligibly small. Furthermore, we clarified that Cyt-c solubilized in ionic liquids caused a structural transformation of Cyt-c, which triggers its functional conversion from an electron-transfer protein to peroxidase.

Comb-shaped poly(ethylene glycol)-modified subtilisin Carlsberg is soluble and highly active in ionic liquids.

Subtilisin Carlsberg conjugated with comb-shaped poly(ethylene glycol) was solubilized in common ionic liquids without adding water, and exhibited higher transesterification activity in an ionic liquid, [Emim][Tf2N], than in organic solvents commonly used for enzymatic biotransformation.