Enhanced electrical properties of BNKT-BMN lead-free ceramics by CaSnO3 doping and their bioactive properties.

There is an increasing interest in using piezoelectric materials, including lead-free piezoceramics for medical applications. As a result, more attention has been placed on investigating the biological properties of these materials. In this research experiment, electrical, mechanical, and biological properties of lead-free 0.99Bi0.5(Na0.8K0.2)0.5TiO3-0.01Bi(Mg2/3Nb1/3)O3 or 0.99BNKT-0.01BMN doped with CaSnO3 (CSO) were investigated. The samples were synthesized by a modified solid-state reaction technique. X-ray diffraction (XRD) analysis showed that the samples presented a single perovskite phase. After adding CSO, electrical properties such as energy storage density (maximum W rec = 781 mJ cm-3) and electro-strain properties (maximum S max = 0.3%) were improved at room temperature. Mechanical properties were also enhanced for the modified samples with maximum values for Vickers hardness (H V) and elastic modulus (E m) of 6.11 GPa and 135 GPa, respectively. Biological assays for cytotoxicity, indicated that the samples had high cell viability, while the simulated body fluid (SBF) test revealed a moderate apatite forming ability. The samples were then coated with hydroxyapatite to improve their apatite-forming ability. The SBF testing for the coated samples showed that the coated samples had high apatite-forming ability. The obtained results pointed to the possibility of ceramics being used for multifunction electrical devices at room temperature and biomaterial applications.

Domain structure and function of α-1,3-glucanase from Bacillus circulans KA-304, an enzyme essential for degrading basidiomycete cell walls.

Bacillus circulans KA-304 α-1,3-glucanase (Agl-KA) includes an N-terminal discoidin domain (DS1), a carbohydrate binding module family 6 (CB6), threonine and proline repeats (TPs), a second discoidin domain (DS2), an uncharacterized conserved domain (UCD), and a C-terminal catalytic domain. Domain deletion enzymes lacking DS1, CB6, and DS2 exhibited lower α-1,3-glucan-hydrolyzing and -binding activities than the wild type, Agl-KA. An α-1,3-glucan binding assay with fluorescent protein fusion proteins indicated that DS1, CB6, and DS2 bound to α-1,3-glucan and fungal cell walls, and that binding efficiency was increased by their combined action. In contrast, UCD did not exhibit any α-1,3-glucan-binding activity. A dramatic decrease in protoplast formation in the Schizophyllum commune mycelium was observed given only a DS1 deletion. An Agl-KA with deletion DS1, CB6, and DS2 produced no protoplasts. These results indicate that the combined actions of DS1, CB6, and DS2 contributed to increased cell-wall binding and were indispensable for efficient Agl-KA cell-wall degradation.

Important Role and Properties of Granular Nanocellulose Particles in an In Vitro Simulated Gastrointestinal System and in Lipid Digestibility and Permeability.

This research evaluated the role and feasibility of the granular nanocellulose particles (GNC) from sugarcane bagasse obtained from enzymatic hydrolysis in reducing lipid digestibility and permeability in an in vitro simulated gastrointestinal (GI) system. GNC concentration (0.02%, w/v) had significantly affected the released free fatty acids (FFA), with a reduction of approximately 20%. Pickering emulsion of a GNC and olive oil simulation mixture revealed higher oil droplet size distribution and stability in the initial stage than the vortexed mixture formation. The difference in particle size distribution and zeta potential of the ingested GNC suspension and GNC-olive oil emulsion were displayed during the in vitro gastrointestinal simulation. GNC particles interacted and distributed surrounding the oil droplet, leading to interfacial emulsion. The GNC concentration (0.01-0.10%, w/v) showed low toxicity on HIEC-6 cells, ranging from 80.0 to 99% of cell viability. The release of FFA containing the ingested GNC suspension and GNC-olive oil emulsion had about a 30% reduction compared to that without the GNC digestion solution. The FFA and triglyceride permeability through the HIEC-6 intestinal epithelium monolayer were deceased in the digesta containing the ingested GNC and emulsion. This work indicated that GNC represented a significantly critical role and properties in the GI tract and reduced lipid digestion and absorption. This GNC could be utilized as an alternative food additive or supplement in fatty food for weight control due to their inhibition of lipid digestibility and assimilation.

N-terminal region of chitinase I of Bacillus circulans KA-304 contained new chitin-biding domain.

Chitinase I (CHI1) of Bacillus circulans KA-304 forms protoplasts from Schizophyllum commune mycelia when the enzyme is combined with α-1,3-glucanase of B. circulans KA-304. CHI1 consists of an N-terminal unknown region and a C-terminal catalytic region classified into the glycoside hydrolase family-19 type. An N-terminal region-truncated mutant of CHI 1 (CatCHI1), which was expressed in Escherichia coli Rosetta-gami B (DE3), lost colloidal chitin- and powder chitin-binding activities. The colloidal chitin- and the powder chitin-hydrolyzing activities of CatCHI1 were lower than those of CHI1, and CatCHI1 was not effective in forming the protoplast. A fusion protein of the N-terminal region of CHI1 and green fluorescent protein (Nterm-GFP) was expressed in E. coli, and the fusion protein was adsorbed to colloidal chitin, powder chitin, and chitosan. Fluorescence microscopy analysis showed that Nterm-GFP bound to the S. commune cell-wall.

Oxidative biotransformation of stemofoline alkaloids.

Biotransformations of stemofoline (1a), (2'S)-hydroxystemofoline (2a), (11Z)-1',2'-didehydrostemofoline (3a) and stemocurtisine (4) were studied through fermentation with Cunninghamella elegans TISTR 3370. Three new stemofoline derivatives; 6 R-hydroxystemofoline (1b), (2'S, 6 R)-dihydroxystemofoline (2b) and (11Z,6R)-1',2'-didehydro-6-hydroxystemofoline (3b), together with the known compound 1',2'-didehydrostemofoline-N-oxide (3c), were produced by C-hydroxylation and N-oxidation reactions. Stemocurtisine was not biotransformed under these conditions. The transformed product 1b was four times more potent (IC50 = 11.01 ± 1.49 µM) than its precursor 1a (IC50 = 45.1 ± 5.46 µM) as an inhibitor against acetylcholinesterase.

Role of chitin binding domain of chitinase A of Streptomyces cyaneus SP-27 in protoplast formation from Schizophyllum commune.

Chitinase A (CHIA) of Streptomyces cyaneus SP-27 forms protoplasts from Schizophyllum commune mycelia when it is combined with alpha-1,3-glucanase of Bacillus circulans KA-304. An N-terminal chitin-binding domain truncated mutant (CatCHIA), which was expressed in Escherichia coli Rosetta-gami B (DE 3), lost most of its colloidal chitin- and powder chitin-binding activity. The colloidal chitin-hydrolyzing, the powder chitin-hydrolyzing, and the protoplast-forming activities of CatCHIA were lower than those of CHIA, suggesting that the chitin-binding domain contributes to the hydrolysis of chitin in the cell-wall of S. commune.

Chemical diversity and anti-acne inducing bacterial potentials of essential oils from selected Elsholtzia species.

Essential oils from the aerial parts of four Elsholtzia species; Elsholtzia stachyodes, Elsholtzia communis, Elsholtzia griffithii and Elsholtzia beddomei were obtained by steam distillation and their chemical components were analysed by gas chromatography-mass spectrometry (GC-MS). Principle Component Analysis was used to identify the chemical variations in the essential oils from these plants, which could be categorised into two groups according to their main chemical components which are acylfuran derivatives and oxygenated monoterpenes. Additionally, the anti-acne inducing bacterial activity against Staphylococcus aureus and Staphylococcus epidermidis were evaluated. The oil from E. stachyodes was the most efficacious against the growth of S. aureus and S. epidermidis having MIC values of 0.78 and 1.56 µL/mL, respectively, and exhibited five times more effective than erythromycin (standard antibiotic).

Synthesis of Hydroxyapatite with Antibacterial Properties Using a Microwave-Assisted Combustion Method.

The prevention of implant-associated infections has been increasing clinically in orthopedic surgery. Hydroxyapatite with antibacterial properties was synthesized using a microwave-assisted combustion method. High crystallinity at low temperature can be achieved using this method. The synthesized hydroxyapatite exhibited a superior clear zone for both Gram-positive and Gram-negative bacteria. Electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) were used for the radical investigation. The application of intelligent ink testing and an antioxidant assay using DPPH reduction were also used to confirm the existence of radicals. These techniques provided data confirming that radicals are responsible for the antibacterial properties. The synthesized antibacterial hydroxyapatite would be a good candidate for the prevention any infection with medical implants and injection materials causing failure in bone repair.