Optimization of Solid-Phase Lactobacillus Fermentation Conditions to Increase γ-Aminobutyric Acid (GABA) Content in Selected Substrates

The purpose of this study was to optimize conditions of solid-phase fermentation of lactic acid bacteria to enhance GABA contents in grains. Optimal solid-phase fermentation conditions that could enhance the GABA content after fermenting Oryza sativa (brown rice) were investigated by changing the Lactobacillus strain, fermentation temperature, fermentation time, and inoculated bacteria number. Avena sativa, Cicer arietinum, and red and brown Lens culinaris were then fermented using the optimal solid-phase fermentation conditions to measure changes in GABA content and antioxidant activity. As a result of the experiment, the optimal solid-phase fermentation conditions to enhance the GABA contents in grains were: fermentation time, 48 h; amounts of bacteria, inoculating 5% of 1 × 107 CFU/mL of lactic acid bacteria; and fermentation temperature, 36 °C. When fermented under this condition, the GABA content increased from 4.64 mg/g to 6.93 mg/g (49.0%) compared to unfermented raw material. The results of the DPPH and ABTS radical scavenging activity assays confirmed that both the GABA content and radical scavenging activity were increased after fermentation. Such solid fermentation conditions developed in this study can be used to support the development of health functional food materials with enhanced GABA content and antioxidant activity

Glycolipids Derived from the Korean Endemic Plant <i>Aruncus aethusifolius</i> Inducing Glucose Uptake in Mouse Skeletal Muscle C2C12 Cells

Aruncus spp. has been used as a traditional folk medicine worldwide for its anti-inflammatory, hemostatic, and detoxifying properties. The well-known species A. dioicus var. kamtschaticus has long been used for multifunctional purposes in Eastern Asia. Recently, it was reported that its extract has antioxidant and anti-diabetic effects. In this respect, it is likely that other Aruncus spp. possess various biological activities; however, little research has been conducted thus far. The present study aims to biologically identify active compounds against diabetes in the Korean endemic plant A. aethusifolius and evaluate the underlying mechanisms. A. aethusifolius extract enhanced glucose uptake without toxicity to C2C12 cells. A bioassay-guided isolation of A. aethusifolius yielded two pure compounds, and their structures were characterized as glycolipid derivatives, gingerglycolipid A, and (2S)-3-linolenoylglycerol-O-β-d-galactopyranoside by an interpretation of nuclear magnetic resonance and high-resolution mass spectrometric data. Both compounds showed glucose uptake activity, and both compounds increased the phosphorylation levels of insulin receptor substrate 1 (IRS-1) and 5′-AMP-activated protein kinase (AMPK) and protein expression of peroxisome proliferator-activated receptor γ (PPARγ). Gingerglycolipid A docked computationally into the active site of IRS-1, AMPK1, AMPK2, and PPARγ (−5.8, −6.9, −6.8, and −6.8 kcal/mol)

Nonvolatile Ferroelectric Memory Circuit Using Black Phosphorus Nanosheet-Based Field-Effect Transistors with P(VDF-TrFE) Polymer

Two-dimensional van der Waals (2D vdWs) materials are a class of new materials that can provide important resources for future electronics and materials sciences due to their unique physical properties. Among 2D vdWs materials, black phosphorus (BP) has exhibited significant potential for use in electronic and optoelectronic applications because of its allotropic properties, high mobility, and direct and narrow band gap. Here, we demonstrate a few-layered BP-based nonvolatile memory transistor with a poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) ferroelectric top gate insulator. Experiments showed that our BP-based ferroelectric transistors operate satisfactorily at room temperature in ambient air and exhibit a clear memory window. Unlike conventional ambipolar BP transistors, our ferroelectric transistors showed only p-type characteristics due to the carbon–fluorine (C–F) dipole effect of the P(VDF-TrFE) layer, as well as the highest linear mobility value of 1159 cm² V^–1 s^–1 with a 10³ on/off current ratio. For more advanced memory applications beyond unit memory devices, we implemented two memory inverter circuits, a resistive-load inverter circuit and a complementary inverter circuit, combined with an n-type molybdenum disulfide (MoS₂) nanosheet. Our memory inverter circuits displayed a clear memory window of 15 V and memory output voltage efficiency of 95%

Non-viral gene delivery strategies for gene therapy: a “ménage à trois” among nucleic acids, materials, and the biological environment

Gene delivery is the science of transferring genetic material into cells by means of a vector to alter cellular function or structure at a molecular level. In this context, a number of nucleic acid-based drugs have been proposed and experimented so far and, as they act on distinct steps along the gene transcription-translation pathway, specific delivery strategies are required to elicit the desired outcome. Cationic lipids and polymers, collectively known as non-viral delivery systems, have thus made their breakthrough in basic and medical research. Albeit they are promising alternatives to viral vectors, their therapeutic application is still rather limited as high transfection efficiencies are normally associated to adverse cytotoxic side effects. In this scenario, drawing inspiration from processes naturally occurring in vivo, major strides forward have been made in the development of more effective materials for gene delivery applications. Specifically, smart vectors sensitive to a variety of physiological stimuli such as cell enzymes, redox status, and pH are substantially changing the landscape of gene delivery by helping to overcome some of the systemic and intracellular barriers that viral vectors naturally evade. Herein, after summarizing the state-of-the-art information regarding the use of nucleic acids as drugs, we review the main bottlenecks still limiting the overall effectiveness of non-viral gene delivery systems. Finally, we provide a critical outline of emerging stimuli-responsive strategies and discuss challenges still existing on the road toward conceiving more efficient and safer multifunctional vectors