Yams (the tubers of the
Dioscorea spp.), consumed and regarded as medicinal food in traditional Chinese herbal medicine, are seasonal foods and easily deteriorate during storage. It is of great ...importance to prolong the storage of yams for supplying in the off-season and without losing nutritional functionality. Three varieties of yams,
Dioscorea alata (cultivars of Tai-Nung no. 2 and Ta-Shan) and
D. purpurea (cultivar of Ming-Chien), were made into flours by freeze-drying, hot air-drying, and drum-drying in this report. The proximate compositions and physical properties, as well as antioxidant activities, of yam flours were determined. While drying methods showed significant effects on the moisture contents of yam flours, they had no marked effects on other components of yam flours. Colour attributes and physical properties were all affected by drying methods to different extents. While freeze-drying usually preserved more antioxidant activity of the yam flours, yam flours made of different yam varieties showed different antioxidant mechanisms.
As very little is known about the molecular structure of dioscorin, the major storage protein of yam tuber, we report here FT-Raman spectroscopic investigation of this yam protein isolated from D. ...alata L., for the first time. According to a series of purification and identification by ion-exchange chromatography, gel chromatography, SDS-PAGE, and MALDI-TOF-MS, it shows that the major storage protein is made up of dioscorin A (M.W. ∼33 kDa) and dioscorin B (M.W. ∼31 kDa). Raman spectral results indicate that the secondary structure of dioscorin A is major in α-helix, while dioscorin B belongs to anti-parallel β- sheet. It also shows that the microenvironment of major amino acids including tyrosine, phenylalanine, tryptophan, and methionine, and cysteine exhibit explicit differences between these two components. The conformation of disulfide bonding in dioscorin A predominates in Gauche-Gauche-Trans form, while Gauche-Gauche-Gauche and Trans-Gauche-Trans share the conformation in dioscorin B. Structural resemblance between dioscorin A and crude yam proteins implies that dioscorin A exhibits structural preference even though its content is lower than dioscorin B.
Detection and surveillance of food commodities containing cyanide is a crucial issue of food safety. In this study, five strains of Pleurotus eryngii (P. eryngii) were grown in submerged culture of ...yeast malt broth (YMB) with the suspected production of HCN. A safety-warranted U-bent glass distilling collector with three enlarged bulbs on each arm was designed to recover the broth vapor. When AgNO3 solution was used as an absorbent to interact with the vapor, a white precipitate was formed. The precipitate was isolated and identified as AgCN by FT-Raman spectroscopic analysis. When the absorbent was substituted by KOH, after evaporation to dryness, dissolved in D2O, and followed by 13C-NMR analysis, a KCN spectrum was achieved. Formation of AgCN and KCN confirmed HCN production in the broth by P. eryngii. When a sodium picrate solution (1.4%) was used as an absorbent and various authentic KCN solutions were applied for distillation and followed by absorbance determination at 510 nm, a linear dose-dependent relationship was obtained and the procedure was applied for HCN quantification of the marketed P. eryngii mushrooms (fruiting body). As estimated, 67.3% of the products contained HCN less than 1.0 mg/kg, 17.3% between 1.0 and 2.0 mg/kg, and 15.4% higher than 2.0 mg/kg. When the mushrooms were sliced and cooked in water at 95 °C for 6 min, 89.1% of the original HCN was lost. When the P. eryngii strains were respectively grown by submerged cultivation in YMB or YMB supplemented with 2.5% glycine for 16 days, HCN content was slightly higher in the latter than in the former for each strain. Keywords: HCN; mushroom; Pleurotus eryngii; picric acid; C13-NMR; FT-Raman; submerged cultivation
The 5th International Taiwan Symposium on Raman Spectroscopy (TISRS 2017) and Taiwan Association of Raman Spectroscopy (TARS) Summer Camp were held from June 27th to 30th at National Chiayi ...University in Taiwan. Four plenary speakers and 14 invited speakers, from France, Hong Kong, India, Italy, Japan, New Zealand, Taiwan, and United States, presented their research findings in TISRS in front of an audience of more than 200 participants from 12 countries. Thirty‐seven posters in biology and material sciences were exhibited at the symposium. Following TISRS, five experts delivered lectures to students in the summer camp. The mission of this congress was to promote continuous developments and applications of Raman spectroscopy, with a focus this year on surface‐enhanced Raman scattering (SERS), tip‐enhanced Raman spectroscopy (TERS), imaging methods, and their applications to molecular, biological, and nanomaterial sciences. This meeting also served as a platform for junior researchers to exhibit their recent studies. In this report, we highlight novel findings and perspectives in Raman spectroscopy that emerged in this symposium. The topics of lecture given in the summer camp are listed.
The mission of this congress was to promote continuous developments and applications of Raman spectroscopy, with a focus this year on surface‐enhanced Raman scattering (SERS), tip‐enhanced Raman spectroscopy (TERS), imaging methods, and their applications to molecular, biological, and nanomaterial sciences. This meeting also served as a platform for junior researchers to exhibit their recent studies.
The amyloidogenic core in the TAR DNA-binding protein (TDP-43) C-terminal fragment has been characterized with its chemical, biochemical, and structural properties delineated. Various properties of ...the core sequence, including membrane impairment ability and the seeding effect, have also been studied.
The abundant accumulation of inclusion bodies containing polyglutamine-expanded mutant huntingtin (mHTT) aggregates is considered as the key pathological event in Huntington's disease (HD). Here, we ...demonstrate that FKBP12, an isomerase that exhibits reduced expression in HD, decreases the amyloidogenicity of mHTT, interrupts its oligomerization process, and structurally promotes the formation of amorphous deposits. By combining fluorescence-activated cell sorting with multiple biophysical techniques, we confirm that FKBP12 reduces the amyloid property of these ultrastructural-distinct mHTT aggregates within cells. Moreover, the neuroprotective effect of FKBP12 is demonstrated in both cellular and nematode models. Finally, we show that FKBP12 also inhibit the fibrillization process of other disease-related and aggregation-prone peptides. Our results suggest a novel function of FKBP12 in ameliorating the proteotoxicity in mHTT, which may shed light on unraveling the roles of FKBP12 in different neurodegenerative diseases and developing possible therapeutic strategies.
We have studied the adsorption of silver nanoparticles (AgNPs) and catechin on readily available commercial zeolite beads. Both adsorbates became available on the zeolite and were several fold more ...concentrated after a simple adsorption process, contributing to a 10-times overall increase in the collision probability between the two adsorbates. We were further able to detect AgNP-induced Surface Enhanced Raman Scattering (SERS) of catechin on the zeolite after sequential depositions of AgNPs and catechin on the zeolite using this process. To demonstrate high reproducibility, 93% of the zeolite sensors assembled this way were tested and proved satisfactory, and gave a distinctive catechin SERS signature. Preparation of the zeolite sensor was extremely easy with a nearly 90% yield.
Adsorbate enrichment on zeolite surface and assembly of a SERS sensor.
Identification of snake venoms is a vital step in the treatment of fatal snakebites. In this study, we use the gold-thiolate interaction between a cysteine residue and gold nanoparticles to establish ...a SERS method for the differentiation of the venoms of
Trimeresurus stejnegeri
and
Bungarus multicinctus
. We confirm the preference of gold nanoparticles over silver for the SERS study of snake venoms by a binding experiment that also functions to differentiate the two venom samples by colorimetry and UV-vis spectroscopy. We report the SERS spectra of
Trimeresurus stejnegeri
and
Bungarus multicinctus
venoms for the first time. The spectra display distinct SERS signatures of the snake venoms on bone-shaped gold nanoparticles made with a house recipe. These signatures correlate to selected segments of the venom proteins due to the anchoring effect of the gold-cysteine bond. The method is quick as it accomplishes
in situ
isolation of the structure of interest to avoid tedious purification of the samples. The location of the interactive cysteine residue makes a novel characteristic of proteins in general.
A colorimetric pre-test and a fast SERS method are developed to detect proteins in their natural matrices, as demonstrated in the characterization and differentiation of two snake venoms.
One-step hydrolysis of chitin to release glucosamine for quantitation was achieved by combining a chitin-containing sample (10−200 mg of sample size) in a test tube with 1 mL of 10 M HCl followed by ...vacuum treatment for 10 min, incubation at 28 °C for 30 min, replenishment with 3 mL of deionized water, nitrogen flushing, screw capping, and heat treatment at 140 °C for 60 min. A phosphate buffer solution (pH 12.5, 0.2 M) was effective in pH stabilization and enhancing colorimetric determination of glucosamine content. When the modified procedure was applied to analyze glucosamine content in the mycelia of various molds, glucosamine content varied mainly depending on mold species. In estimations of mold growth of the uninoculated peanut kernels incubated under a humidified condition for 5 weeks, cooked rice and soybean inoculated with conidia of Aspergillus oryzae for koji preparation, logarithms of the internal mold populations and glucosamine contents both increased with increases of incubation time. The modified procedure provided a rapid and reliable estimation of mold growth in various substrates. Keywords: Glucosamine; chitin; MBTH; buffer solution; internal mold population; peanut; koji
The amyloidogenic core in the TAR DNA-binding protein (TDP-43) C-terminal fragment has been characterized with its chemical, biochemical, and structural properties delineated. Various properties of ...the core sequence, including membrane impairment ability and the seeding effect, have also been studied.
The amyloidogenic core peptide derived from the TDP-43 C-terminus can disrupt the liposome membrane and induce nascent TDP-43 aggregation.
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