Grouping, spectrum-effect relationship and antioxidant compounds of Chinese propolis from different regions using multivariate analyses and off-line anti-DPPH assay

49 samples of propolis from different regions in China were collected and analyzed for their chemical compositions, contents of total flavonoids (TFC), total phenolic acid (TPC) and antioxidant activity. High-performance liquid chromatography (HPLC) analysis identified 15 common components, including key marker compounds pinocembrin, 3-O-acetylpinobanksin, galangin, chrysin, benzyl p-coumarate, pinobanksin and caffeic acid phenethyl ester (CAPE). Cluster analysis (CA) and correlation coefficients (CC) analysis showed that these propolis could be divided into three distinct groups. Principal component analysis (PCA) and multiple linear regression analysis (MLRA) revealed that the contents of isoferulic acid, caffeic acid, CAPE, 3,4-dimethoxycinnamic acid, chrysin and apigenin are closely related to the antioxidant properties of propolis. In addition, eight peak areas decreased after reacting with 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals, indicating that these compounds have antioxidant activity. The results indicate that the grouping and spectrum-effect relationship of Chinese propolis are related to their chemical compositions, and several compounds may serve as a better marker for the antioxidant activity of Chinese propolis than TFC and TPC. The findings may help to develop better methods to evaluate the quality of propolis from different geographic origins

Coexistence of diploid, triploid and tetraploid crucian carp (Carassius auratus) in natural waters

<p>Abstract</p> <p>Background</p> <p>Crucian carp (abbreviated CC) belongs to the genus of <it>Carassius </it>within the family of <it>Cyprinidae</it>. It has been one of the most important freshwater species for Chinese aquaculture and is especially abundant in the Dongting water system of Hunan province. CC used to be considered as all diploid forms. However, coexistence of diploid (abbreviated 2nCC), triploid (abbreviated 3nCC) and tetraploid crucian carp (abbreviated 4nCC) population of the Dongting water system was first found by our recently researches.</p> <p>Results</p> <p>We examined the ploidy level and compared biological characteristics in different ploidy CC. In reproductive mode, 2nCC was bisexual generative and 4nCC generated all-female offspring by gynogenesis. However, 3nCC generated progenies in two different ways. 3nCC produced bisexual triploid offspring fertilized with 3nCC spermatozoa, while it produced all-female triploid offspring by gynogenesis when its ova were activated by heterogenous spermatozoa. The complete mitochondrial DNA of three different ploidy fishes was sequenced and analyzed, suggesting no significant differences. Interestingly, microchromosomes were found only in 3nCC, which were concluded to be the result of hybridization. Allogenetic DNA fragments of Sox genes were obtained in 3nCC and 4nCC, which were absent in 2nCC. Phylogenetics analysis based on Sox4 gene indicated 3nCC and 4nCC formed a separate group from 2nCC.</p> <p>Conclusions</p> <p>In summary, this is the first report of the co-existence of three types of different ploidy crucian carps in natural waters in China. It was proved that the coexistence of different ploidy CC was reproductively maintained. We further hypothesized that 3nCC and 4nCC were allopolyploids that resulted from hybridization. The different ploidy CC population we obtained in this study possesses great significance for the study of polyploidization and the evolution of vertebrates.</p

Method for the Energy Storage Configuration of Wind Power Plants with Energy Storage Systems used for Black-Start

With the increasing participation of wind generation in the power system, a wind power plant (WPP) with an energy storage system (ESS) has become one of the options available for a black-start power source. In this article, a method for the energy storage configuration used for black-start is proposed. First, the energy storage capacity for starting a single turbine was determined. Then, a hierarchical planning model was established. This model did not consider the starting efficiency of the WPP, but it did consider the layout of the energy storage in the WPP and the balance of the terminal voltage when starting the WPP. Finally, the feasibility and value of the proposed method and model were verified in a 49.5 MW WPP with an ESS (a power rating of 2.24 MW and energy capacity of about 1.68 MWh). The result suggests that configuring an ESS with a small capacity on the side of the turbine can achieve black-start for a WPP with an ESS as the power source

Mitochondrial DNA analyses found five novel mutations in idiopathic epilepsy patients

Epilepsy is a common and chronic neurological disease with a high degree of genetic heterogeneity. The etiology and pathogenesis of the disease have not been fully understood. Many studies suggested that there was a reciprocal relationship between mitochondrial dysfunction and epilepsy, but few studies focused on the mitochondrial genome (mtDNA) of the epilepsy patient which was extremely important for the mitochondrial function. In our study, we obtained complete mtDNA sequences of 27 idiopathic epilepsy patients and healthy people, and compared the sequence data with 30,000 GenBank sequences including 277 Han Chinese mtDNA sequences. We analyzed each variant that might be related to disease and examined the statistically significant variant in more than 300 patients and healthy people. Ultimately, we identified 27 variants which were reported to be associated with diseases, 4 rare variants (321T > G, 15973 T > C, 3897C > A, 12580 C > T), and a nonsynonymous variant (3571 C > T) which was predicted to be damaging. Although no variant was found to be significantly associated with epilepsy, our study provided a new insight into epilepsy study on an aspect of the mitochondrial genome

Gadolinium Oxide Nanoparticles and Aptamer-Functionalized Silver Nanoclusters-Based Multimodal Molecular Imaging Nanoprobe for Optical/Magnetic Resonance Cancer Cell Imaging

Multimodal molecular imaging has attracted more and more interest from researchers due to its combination of the strengths of each imaging modality. The development of specific and multifunctional molecular imaging probes is the key for this method. In this study, we fabricated an optical/magnetic resonance (MR) dual-modality molecular imaging nanoprobe, polyethylene glycol-coated ultrasmall gadolinium oxide (PEG-Gd₂O₃)/aptamer-Ag nanoclusters (NCs), for tracking cancer cells. To achieve this aim, PEG-Gd₂O₃ nanoparticles (NPs) as magnetic resonance imaging (MRI) contrast agent and aptamer functionalized silver nanoclusters (aptamer-Ag NCs) as fluorescence reporter were first synthesized by a one-pot approach, respectively. They were then conjugated by the covalent coupling reaction between the carboxyl group on the surface of PEG-Gd₂O₃ NPs and amino group modified on the 5′-end of AS1411 aptamer. With a suitable ratio, the fluorescence intensity of aptamer-Ag NCs and MR signal of PEG-Gd₂O₃ nanoparticles could both be enhanced after the formation of PEG-Gd₂O₃/aptamer-Ag NCs nanoprobe, which favored their application for multimodal molecular imaging. With this nanoprobe, MCF-7 tumor cells could be specifically tracked by both fluorescence imaging and magnetic resonance imaging <i>in vitro.</i