The brown seaweed Sargassum hemiphyllum exhibits α-amylase and α-glucosidase inhibitory activity and enhances insulin release in vitro

Diabetes is one of the most prevalent chronic diseases globally. In this study, major polyphenols (17.35 ± 0.93–36.66 ± 2.01 mg/g) and minor fucoxanthin (non detected 15.12 ± 0.09 mg/g) were isolated from water, ethanol, and acetone extracts (WES, EES, and AES, respectively) of Sargassum hemiphyllum. Inhibition of α-amylase, α-glucosidase, sucrose, and maltase activities and stimulation of insulin secretion was greater with AES than with WES or EES and correlated with polyphenol and fucoxanthin concentrations in extracts. Moreover, 250 μg/ml EES and AES significantly increased insulin secretion in the presence of 25 mg/ml glibenclamide to higher levels than those obtained with 50 mg/ml glibenclamide. None of the extracts exhibited cytotoxicity, exacerbated the side effects of glibenclamide, or inhibited glibenclamide-induced insulin secretion. These results suggested that the S. hemiphyllum extracts WES, EES, and AES could be used as pharmaceuticals and functional foods to reduce dosages of synthetic diabetes drugs.     

Taurine resumed neuronal differentiation in arsenite-treated N2a cells through reducing oxidative stress,endoplasmic reticulum stress,and mitochondrial dysfunction

The goal of the study is to investigate the preventive effect of taurine against arsenite-induced arrest of neuronal differentiation in N2a cells. Our results revealed that taurine reinstated the neurite outgrowth in arsenite-treated N2a cells. Meanwhile, arsenite-induced oxidative stress and mitochondrial dysfunction as well as degradation of mitochondria DNA (mtDNA) were also inhibited by co-treatment of taurine. Since oxidative stress and mitochondrial dysfunction is closely associated with endoplasmic reticulum (ER) stress, we further examined indicators of ER stress, 78 kDa glucose-regulated protein (GRP78), and C/EBP-homologous protein (CHOP) protein expression. The results demonstrated that taurine significantly reduced arsenite-induced ER stress in N2a cells. In the parallel experiment, arsenite-induced disruption of intracellular calcium homeostasis was also ameliorated by taurine. The proven bio-function of taurine preserved a preventive effect against deleteriously cross-talking between oxidative stress, mitochondria, and ER. Overall, the results of the study suggested that taurine reinstated neuronal differentiation by inhibiting oxidative stress, ER stress, and mitochondrial dysfunction in arsenite-treated N2a cells.     

Multiplex genotyping based on the melting temperature of a single locked nucleic acid probe

Locked nucleic acid (LNA) is a modified RNA nucleotide that can be incorporated at specific positions to generate probes with the desired length, melting temperature (T_M), and specificity. Here, we describe a method of multiplex genotyping based on dramatic shifts in the T_M of a single dual-labeled LNA probe. Using this method, two varieties of the hairtail fish Trichiurus lepturus can be distinguished from each other, as well as from Trichiurus japonicus, based on a 1- to 2-bp difference in a fragment of mitochondrial cytochrome oxidase subunit 1. The shift in T_M was 15 °C for a 1-bp mismatch and 27 °C for a 2-bp mismatch, indicating remarkable specificity. We anticipate that the method will be widely useful in applications such as species identification that require accurate, multiplex, and efficient detection of DNA polymorphisms.     

Biomimetic repeat protein derived from Xenopus tropicalis for fibrous scaffold fabrication

Collagen, silk, and elastin are the fibrous proteins consist of representative amino acid repeats. Because these proteins exhibited distinguishing mechanical properties, they have been utilized in diverse applications, such as fiber‐based sensors, filtration membranes, supporting materials, and tissue engineering scaffolds. Despite their infinite prevalence and potential, most studies have only focused on a few repeat proteins. In this work, the hypothetical protein with a repeat motif derived from the frog Xenopus tropicalis was obtained and characterized for its potential as a novel protein‐based material. The codon‐optimized recombinant frog repeat protein, referred to as ‘xetro’, was produced at a high rate in a bacterial system, and an acid extraction‐based purified xetro protein was successfully fabricated into microfibers and nanofibers using wet spinning and electrospinning, respectively. Specifically, the wet‐spun xetro microfibers demonstrated about 2‐ and 1.5‐fold higher tensile strength compared with synthetic polymer polylactic acid and cross‐linked collagen, respectively. In addition, the wet‐spun xetro microfibers showed about sevenfold greater stiffness than collagen. Therefore, the mass production potential and greater mechanical properties of the xetro fiber may result in these fibers becoming a new promising fiber‐based material for biomedical engineering. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 659–664, 2015.     

Source and role of intestinally derived lysophosphatidic acid in dyslipidemia and atherosclerosis

We previously reported that i) a Western diet increased levels of unsaturated lysophosphatidic acid (LPA) in small intestine and plasma of LDL receptor null (LDLR^−/−) mice, and ii) supplementing standard mouse chow with unsaturated (but not saturated) LPA produced dyslipidemia and inflammation. Here we report that supplementing chow with unsaturated (but not saturated) LPA resulted in aortic atherosclerosis, which was ameliorated by adding transgenic 6F tomatoes. Supplementing chow with lysophosphatidylcholine (LysoPC) 18:1 (but not LysoPC 18:0) resulted in dyslipidemia similar to that seen on adding LPA 18:1 to chow. PF8380 (a specific inhibitor of autotaxin) significantly ameliorated the LysoPC 18:1-induced dyslipidemia. Supplementing chow with LysoPC 18:1 dramatically increased the levels of unsaturated LPA species in small intestine, liver, and plasma, and the increase was significantly ameliorated by PF8380 indicating that the conversion of LysoPC 18:1 to LPA 18:1 was autotaxin dependent. Adding LysoPC 18:0 to chow increased levels of LPA 18:0 in small intestine, liver, and plasma but was not altered by PF8380 indicating that conversion of LysoPC 18:0 to LPA 18:0 was autotaxin independent. We conclude that i) intestinally derived unsaturated (but not saturated) LPA can cause atherosclerosis in LDLR^−/− mice, and ii) autotaxin mediates the conversion of unsaturated (but not saturated) LysoPC to LPA.