109 research outputs found
Effect of Microwave-Ultrasound Treatment on Physicochemical and Structural Properties of Highland Barley β-Glucan
The extraction efficiency, physicochemical properties, and structural characteristics of β-glucan extracted from highland barley branby sequential microwave-ultrasound-assisted extraction were explored. At the same heating rate, microwave enhanced α-amylase activity. The extraction efficiency of highland barley β-glucan was correlated with ultrasound power and treatment time. An ultrasound power of 600 W for 30 min and microwave heating at 60 ℃ for 30 min resulted in the maximum β-glucan yield of (6.30 ± 0.38)%. The results of physicochemical properties showed that with increasing sonication time up to 40 min, the solubility and foaming capacity of barley β-glucan increased significantly (P < 0.05), while the turbidity and emulsifying capacity decreased significantly (P < 0.05). The results of particle size distribution showed that with increasing sonication time, the relative molecular mass of barley β-glucan decreased, and ultrasound changed the rheological behavior of β-glucan, decreasingits viscosity and resulting in shear thinning. The infrared spectroscopic results showed that sonication did not change the functional groups of β-glucan, but it caused partial breakage of the glycosidic bonds. The microscopic results showed that ultrasonic treatment led to a looser structure of barley β-glucan, which was conducive to improving its extraction efficiency. Therefore, the microwave-ultrasound-assisted extraction of β-glucan from highland barley provides a basis for developing new food types and functional products
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
Gamma linolenic acid suppresses hypoxia-induced gastric cancer cell growth and epithelial-mesenchymal transition by inhibiting the Wnt/b-catenin signaling pathway
Introduction. Gastric cancer is one of the most common malignancies in China and the fifth most common cancer in the world. Gamma linolenic acid (GLA) was reported to have anti-inflammatory and anti-cancer effects. The purpose of this research was to investigate the effect and mechanism of GLA on gastric cancer cell growth under hypoxic conditions.
Material and methods. The hypoxia models of SGC-7901 and MGC-803 cells were established, and then were exposed to different concentrations of 50, 100 or 200 μM GLA. MTT assay, colony formation assay, wound healing assay and transwell assay were used to investigate the effects of GLA treatment on gastric cancer cell growth under hypoxia (1% O2). The expression of apoptosis- and epithelial-mesenchymal transition (EMT)-related proteins was detected by qPCR and western blot.
Results. GLA treatment significantly decreased viability and inhibited colony formation (p < 0.05, p < 0.01) of SGC-7901 and MGC-803 cells under hypoxia. Western blotting analysis showed that GLA treatment decreased the expression of proliferating cell nuclear antigen (PCNA), microchromosome maintenance complex component 2 (MCM-2) and anti-apoptotic protein Bcl-2, while increased the expression of pro-apoptotic proteins (Bax and Cleaved Caspase-3) (p < 0.05 and p < 0.01). In addition, Wound healing analysis and Transwell assays showed that GLA treatment inhibited the migration and invasion of SGC-7901 and MGC-803 cells in a dose-dependent manner (p < 0.01). Western blotting analysis showed that GLA treatment increased the expression of epithelial marker proteins (g-catenin and E-cadherin), while decreased the expression of stromal and extracellular matrix marker proteins (fibronectin, Snail and b-catenin) (p < 0.01). Further analyses showed that GLA treatment decreased the expression of b-catenin in Wnt/b-catenin pathway (p < 0.01). Moreover, exogenous Wnt3a reversed the inhibitory effect of GLA on b-catenin expression, and further reversed the inhibitory effect of GLA on gastric cancer cell growth and EMT markers (p < 0.05, p < 0.01).
Conclusion. These findings suggest that GLA should be tested in animal models and in clinical studies as a potentially effective bioactive phytochemical substance for the treatment of gastric cancer
ERTool: A Python Package for Efficient Implementation of the Evidential Reasoning Approach for Multi-Source Evidence Fusion
Background: Multi-source evidence fusion aims to process and combine evidence from different sources to support rational and reliable decision-making. The evidential reasoning (ER) approach is a helpful method to deal with information from multiple sources with uncertainty. It has been widely used in business analytics, healthcare management, and other fields for optimal decision-making. However, computerized implementation of the ER approach usually requires much expertise and effort. At present, some ER-based computerized tools, such as the intelligent decision system (IDS), have been developed by professionals to provide decision support. Nevertheless, IDS is not open source, and the user interfaces are a bit complicated for non-professional users. The lack of a free-to-access and easy-to-use computerized tool limits the application of ER. Methods: We designed and developed a Python package that could efficiently implement the ER approach for multi-source evidence fusion. Further, based on it, we built an online web-based system, providing not only real-time evidence fusion but also visualized illustrations of combined results. Finally, a comparison study between the Python package and IDS was conducted. Results: A Python package, ERTool, was developed to implement the ER approach automatically and efficiently. The online version of the ERTool provides a more convenient way to handle evidence fusion tasks. Conclusions: ERTool, compatible with Python 3 and can be installed through the Python Package Index at https://pypi.org/project/ERTool/, was developed to implement the ER approach. The ERTool has advantages in easy accessibility, clean interfaces, and high computing efficiency, making it a key tool for researchers and practitioners in multiple evidence-based decision-making. It helps bridge the gap between the algorithmic ER and its practical application and facilitates its widespread adoption in general decision-making contexts
Biomimicking polysaccharide nanofibers promote vascular phenotypes : a potential application for vascular tissue engineering
The potential of electrospun pullulan/dextran (P/D) nanofibers (average diameter = 323 nm) for vascular tissue engineering applications is explored. The mechanical properties of the nanofibers are of the same order of magnitude as that of human arteries (Young's modulus ≈0.88 MPa; tensile strength ≈0.35 MPa). It is demonstrated that the nanofiber topography enables cell adhesion and that the endothelial phenotype is maintained on the nanofibers. Moreover, P/D nanofibers support a stable confluent monolayer of endothelial cells over 14 d. SMCs seeded on nanofibers display similar levels of alpha smooth muscle actin and a lower proliferation rate than cells on 2D cultures. The observations suggest that nanofibers promote a shift to a quiescent contractile phenotype in SMCs
Formation of lipase Candida sp 99-125 CLEAs in mesoporous silica: characterization and catalytic properties
Mesoporous silica (MPS) was synthesized and used as a support for lipase Candida sp. 99-125 immobilization. The immobilization procedure was simple and effective: lipase Candida sp. 99-125 was first immobilized in the MPS by adsorption (named ADL@MPS), then chemical crosslinking was conducted for stabilizing the lipase and inhibiting leakage, and cross-linked enzyme aggregates (CLEAs) of Candida sp. 99-125 lipase in the MPS were obtained (named CLL@MPS). The stability of ADL@MPS and CLL@MPS was investigated. Compared with ADL@MPS and native lipase, CLL@MPS showed outstanding stability under vigorous shaking conditions and the thermal stability of CLL@MPS in the presence of organic solvents was also improved. Additionally, CLL@MPS exhibited high catalytic performance in hydrolysis, esterification, and transesterification reactions with increased stability and recyclability
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