583 research outputs found

    The friction coefficients of liquids

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    Species identification of a laboratory strain belonging to the family Arvicolinae

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    This study investigated the taxonomic status of a laboratory strain belonging to the family Arvicolinae for which the wild species name is unknown. This vole strain, though considered formerly a Lemming, was distinguishable from any Lemmus species by features of its appearance, skull and molar morphology, and conventional chromosomal pattern. Subsequently, we read the nucleotide sequence of the mitochondrial cytochrome b (Cyb) gene and constructed a molecular phylogenetic tree. We found that this vole strain belongs to the same clade as Microtus guenth

    Identification of Cysteine Proteases and Screening of Cysteine Protease Inhibitors in Biological Samples by a Two-Dimensional Gel System of Zymography and Reverse Zymography

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    We have developed a two-dimensional (2D-) gel system of zymography and reverse zymography for the detection and characterization of proteases and protease inhibitors. Isoelectric focusing (IEF) agarose gels with pH gradients were employed for separation in the first-dimension and sodium dodecyl sulfate (SDS)-polyacrylamide gel copolymerized with gelatin used for the second dimension. Proteases and protease inhibitors separated by IEF gel were applied on the second gel without trichloroacetic acid (TCA) fixation. Protease activity in the 2D-gel was visualized as transparent spots where gelatin substrate was digested after commassie brilliant blue (CBB) staining. Some of the transparent spots from the skin mucus extract of rainbow trout were determined to be a cysteine protease through use of E-64 or CA-074. In the reverse zymography technique, the gel was incubated with papain solution at 37 ºC for 18 h. Cysteine protease inhibitors from broad bean seeds were detected as clear blue spots after CBB staining. The amino (N-) terminal sequences of four papain inhibitor spots thus detected were demonstrated to be identical to that of favin β chain, a broad bean lectin. Taken together, our system can be considered to be an efficient technique for discovering and characterizing new proteases and protease inhibitors in biological samples. This is the first report describing a 2D-gel system of zymography and reverse zymography

    The Relationships Between Biological Activities and Structure of Flavan-3-Ols

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    Flavan-3-ols are involved in multiple metabolic pathways that induce inhibition of cell proliferation. We studied the structure-activity relationship of gallic acid (GA) and four flavan-3-ols: epigallocatechin gallate (EGCG), epigallocatechin (EGC), catechin (C), and epicatechin (EC). We measured the cell viability by the MTT assay and we determined the concentration of testing compound required to reduce cell viability by 50% (IC50). All tested compounds showed a dose-dependent and time-dependent inhibitory antiproliferative effect on Hs578T cells; IC50 values varying from the 15.81 to 326.8 μM. Intracellular ROS (reactive oxygen species) were quantified using a fluorescent probe 2′,7′-dichlorofluorescin diacetate (DCFH-DA). Only the treatment with 10 μM EGC and EGCG was able to induce a significant decrease of ROS concentration and increased levels of ROS were registered for 100 μM EGCG, EGC and GA. Flavans-3-ols and GA induced apoptosis in a dose- and time-dependent manner, which indicated that the induction of apoptosis mediated their cytotoxic activity at least partially. The galloylated catechins have shown a stronger antiproliferative activity and apoptotic effect than the one produced by non galloylated catechins. The galloylated flavan-3-ols are potential therapeutic agents for patients with triple negative breast cancer via induction of apoptosis

    Major Phenolic Compounds, Antioxidant Capacity and Antidiabetic Potential of Rice Bean (Vigna umbellata L.) in China

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    Interest in edible beans as nutraceuticals is increasing. In the present study, the individual phenolic acids, the total phenolic content (TPC), the total flavonoid content (TFC), and the antioxidant and antidiabetic potential of 13 varieties of rice beans from China were investigated. Eight phenolic compounds (catechin, epicatechin, p-coumaric acid, ferulic acid, vitexin, isovitexin, sinapic acid, quercetin) were analyzed on an ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) system. The rice bean varieties had significant differences in total phenolic compounds (ranging from 123.09 ± 10.35 to 843.75 ± 30.15 μg/g), in TPC (ranging from 3.27 ± 0.04 to 6.43 ± 0.25 mg gallic acid equivalents (GAE)/g), in TFC (ranging from 55.95 ± 11.16 to 320.39 ± 31.77 mg catechin (CE)/g), in antioxidant activity (ranging from 39.87 ± 1.37 to 46.40 ± 2.18 μM·TE/g), in α-glucosidase inhibition activity (ranging from 44.32 ± 2.12 to 68.71 ± 2.19) and in advanced glycation end products formation inhibition activity (ranging from 34.11 ± 0.59 to 75.75 ± 0.33). This study is the first report on phytochemistry and biological activities in rice beans

    Natural Variation in an ABC Transporter Gene Associated with Seed Size Evolution in Tomato Species

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    Seed size is a key determinant of evolutionary fitness in plants and is a trait that often undergoes tremendous changes during crop domestication. Seed size is most often quantitatively inherited, and it has been shown that Sw4.1 is one of the most significant quantitative trait loci (QTLs) underlying the evolution of seed size in the genus Solanum—especially in species related to the cultivated tomato. Using a combination of genetic, developmental, molecular, and transgenic techniques, we have pinpointed the cause of the Sw4.1 QTL to a gene encoding an ABC transporter gene. This gene exerts its control on seed size, not through the maternal plant, but rather via gene expression in the developing zygote. Phenotypic effects of allelic variation at Sw4.1 are manifested early in seed development at stages corresponding to the rapid deposition of starch and lipids into the endospermic cells. Through synteny, we have identified the Arabidopsis Sw4.1 ortholog. Mutagenesis has revealed that this ortholog is associated with seed length variation and fatty acid deposition in seeds, raising the possibility that the ABC transporter may modulate seed size variation in other species. Transcription studies show that the ABC transporter gene is expressed not only in seeds, but also in other tissues (leaves and roots) and, thus, may perform functions in parts of the plants other than developing seeds. Cloning and characterization of the Sw4.1 QTL gives new insight into how plants change seed during evolution and may open future opportunities for modulating seed size in crop plants for human purposes
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