Ultraviolet Irradiation Increased the Concentration of Vitamin D2 and Decreased the Concentration of Ergosterol in Shiitake Mushroom (Lentinus edodes) and Oyster Mushroom (Pleurotus ostreatus) Powder in Ethanol Suspension.

Vitamin D deficiency is a serious global health problem. Edible mushrooms are a good source of vitamin D for human health. The objective of this experiment was to investigate the efficiency of converting its precursor ergosterol to vitamin D2 in shiitake mushroom (Lentinus edodes) and oyster mushroom (Pleurotus ostreatus) powder in ethanol suspension under ultraviolet (UV) irradiation. UV irradiation conditions were optimized for several parameters, such as material form, wavelength, wavelength combination, and exposure time. Under the optimal conditions, UV irradiation increased the concentrations of vitamin D2 from undetectable to 40.59 ± 1.16 µg/g (dw) in dry shiitake mushroom powder and to 677.28 ± 40.42 µg/g (dw) (an approximately 16.69-fold increase) in ethanol suspension. The concentration of vitamin D2 increased from undetectable to 23.71 ± 5.72 µg/g (dw) in the dry oyster mushroom powder upon UV irradiation, whereas UV irradiation increased the concentration to 275.32 ± 48.45 µg/g (dw) (an approximately 11.61-fold increase) in the ethanol suspension. Comparing the effects of varying combinations of wavelengths showed that irradiation with UV-A, UV-C, or a combination of both is more effective than UV-B irradiation. In addition, the increase in vitamin D2 in shiitake mushrooms irradiated by UV-C was time-dependent, that is, dose-dependent. Nevertheless, the increase rates decreased with time. The concentration of ergosterol decreased with the increase in vitamin D2, but ergosterol was only partially converted to vitamin D2, whereas most of the ergosterol was probably UV-degraded. Exposure to ultraviolet light in ethanol suspension offers an effective way to increase the concentration of vitamin D2 and thus improve the nutritional value of edible mushrooms, as well as make them more functional as a source of vitamin D to improve the consumer health.

Dynamic Electrochemical Control of Cell Capture-and-Release Based on Redox-Controlled Host-Guest Interactions.

Artificial control of cell adhesion on smart surface is an on-demand technique in areas ranging from tissue engineering, stem cell differentiation, to the design of cell-based diagnostic system. In this paper, we report an electrochemical system for dynamic control of cell catch-and-release, which is based on the redox-controlled host-guest interaction. Experimental results reveal that the interaction between guest molecule (ferrocene, Fc) and host molecule (ß-cyclodextrin, ß-CD) is highly sensitive to electrochemical stimulus. By applying a reduction voltage, the uncharged Fc can bind to ß-CD that is immobilized at the electrode surface. Otherwise, it is disassociated from the surface as a result of electrochemical oxidation, thus releasing the captured cells. The catch-and-release process on this voltage-responsive surface is noninvasive with the cell viability over 86%. Moreover, because Fc can act as an electrochemical probe for signal readout, the integration of this property has further extended the ability of this system to cell detection. Electrochemical signal has been greatly enhanced for cell detection by introducing branched polymer scaffold that are carrying large quantities of Fc moieties. Therefore, a minimum of 10 cells can be analyzed. It is anticipated that such redox-controlled system can be an important tool in biological and biomedical research, especially for electrochemical stimulated tissue engineering and cell-based clinical diagnosis.

Electrochemical Detection and Distribution Analysis of ß-Catenin for the Evaluation of Invasion and Metastasis in Hepatocellular Carcinoma.

Pro-metastatic cell signaling controls the switch to distant metastasis and the final cancer death. In hepatocellular carcinoma (HCC), this death switch is turned on by the multiprotein interactions of ß-catenin with many transcription factors, so a method to assay the bioactivity of ß-catenin to participate in these pro-metastatic protein/protein interactions has been proposed in this work. This method employs cost-effective peptide-based protein targeting ligands, while the electrochemical catalytic cross-linking in this method also "finalize" the noncovalent molecular recognition, so that the robustness can be improved to enable detection of relatively more complex biosamples. In studying clinical samples with the proposed method, the cellular distribution and overall expression of ß-catenin show a parallel with the pathological grade of the sample, particularly, nuclear translocation. The pro-metastatic activation of ß-catenin can also be observed as evidently correlated with higher-grade cases, suggesting the active role of ß-catenin in promoting metastasis. According to these results, the proposed method may have the prospective use as a prognostic tool for evaluating the potential of invasion and metastasis in cancer.

Investigation of MTH1 activity via mismatch-based DNA chain elongation.

Accumulation and misincorporation of oxidative damaged 8-oxo-7,8-dihydroguanine triphosphates (8-oxo-dGTP) in genomic DNA may cause serious cellular function disorders. MutT Homolog 1 (MTH1), a protein enzyme that can help to prevent 8-oxo-dGTP misincorporation, plays critical roles in oxidative stress neutralization, oncogene-associated tumor malignancy, and anticancer therapies. So, in this work, a simple and function-oriented method is developed for the assay of MTH1 activity. Specifically, a mismatch-based ("8-oxoG: A" mismatch) DNA chain elongation strategy (MB-DCE) is firstly proposed to reveal the misincorporation efficiency of 8-oxo-dGTP. Then, further coupled with the inherent activity of MTH1 to prevent 8-oxo-dGTP misincorporation, a relationship can be established to reveal the activity of MTH1 through MB-DCE. As the method is designed directly towards the cellular function of MTH1, activity of MTH1 in different breast cancer cell lines has been detected, implying the potential application of this assay method for biomedical research and clinical diagnose in the future.