Improved Methodology for Identification of Cryptomonads: Combining Light Microscopy and PCR Amplification

( Shuang Xia ),( Ying Yin Cheng ),( Huan Zhu ),( Guo Xiang Liu ),( Zheng Yu Hu ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.3

Cryptomonads are unicellular, biflagellate algae. Generally, cryptomonad cells cannot be preserved well because of their fragile nature, and an improved methodology should be developed to identify cryptomonads from natural habitats. In this study, we tried using several cytological fixatives, including glutaraldehyde, formaldehyde, and their combinations to preserve field samples collected from various waters, and the currently used fixative, Lugol`s solution was tested for comparison. Results showed that among the fixatives tested, glutaraldehyde preserved the samples best, and the optimal concentration of glutaraldehyde was 2%. The cell morphology was well preserved by glutaraldehyde. Cells kept their original color, volume, and shape, and important taxonomic features such as furrow/gullet complex, ejectosomes, as well as flagella could be observed clearly, whereas these organelles frequently disappeared in Lugol`s solution preserved samples. The osmotic adjustments and buffers tested could not preserve cell density significantly higher. Statistical calculation showed the cell density in the samples preserved by 2% glutaraldehyde remained stable after 43 days of the fixation procedure. In addition, DNA was extracted from glutaraldehyde preserved samples by grinding with liquid nitrogen and the 18S rDNA sequence was amplified by PCR. The sequence was virtually identical to the reference sequence, and phylogenetic analyses showed very close relationship between it and sequences from the same organism. To sum up, the present study demonstrated that 2% unbuffered glutaraldehyde, without osmotic adjustments, can preserve cryptomonads cells for identification, in terms of both light microscopy and phylogenetic analyses based on DNA sequences.

CFD analysis of the flow blockage in a rectangular fuel assembly of the IAEA 10 MW MTR research reactor

Xia, Shuang,Zhou, Xuhua,Hu, Gaojie,Cao, Xiaxin Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.9

When a nuclear reactor with rectangular fuel assemblies runs for a long time, impurities and debris may be taken into coolant channels, which may cause flow blockage, and the blocked fuel assemblies might be destroyed. Therefore, the purpose of this study is to perform a thermal-hydraulic analysis of a rectangular fuel assembly by STAR-CCM+, under the condition of one subchannel with 80% blockage ratio. A rectangular fuel assembly of the International Atomic Energy Agency (IAEA) 10 MW material test reactor (MTR) is chosen. In view of the gasket material taken into the coolant channel is close to the single side of the coolant channel, in the flow blockage accident of the Oak Ridge Research Reactor (ORRR), a new blockage category called single side blockage is attempted. The blockage positions include inlet, middle and outlet, and the blockage is set as a cuboid. It is found by simulations that the blockage redistributes the mass flow rate, and large vortices appear locally. The peak temperature of the cladding is maximum, when the blockage is located at the single side of the coolant channel inlet, and no boiling occurs in all blockage cases. Moreover, as the height of the blockage increases, the damage caused by the blockage increases slightly.

A Highly Integrated Automatic Fiber Optical Gyroscope Sensing Coil Winding System

Shuang-Chao Ge,Rui-Feng Yang,Chen-Xia Guo 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.2

Fiber optic gyroscope (FOG) is a new type of optical sensor used to measure the rotating angular velocity. As the core component, fiber optic coil (FOC) plays a decisive role in the FOG output precision. The manufacturing level and efficiency of FOC have been main factors restricting the application and development of high precision FOG. Precision mechanical positioning method based on the photoelectric devices was researched, and high-performance fully automatic micro mechanical error compensation technique was developed. On these basis, automatic fiber distribution and winding control technology were realized. Eventually a multifunctional system was developed with fiber splitting module, fiber winding module, and calibration module. This system could accomplish automatic preparation of FOC with quadrupolar symmetric pattern according to the parameters set by user. The principle and working flow of each functional module are discussed in details. Experiments show that the system can achieve automatic speed changing, automatic reversing, constant small tension control and precise fiber arrangement. The new designed system greatly improve FOC production efficiency and is conductive to promotinghigh level FOG development.

Arginine Supplementation Recovered the IFN-γ-Mediated Decrease in Milk Protein and Fat Synthesis by Inhibiting the GCN2/eIF2α Pathway, Which Induces Autophagy in Primary Bovine Mammary Epithelial Cells

Xia, Xiaojing,Che, Yanyi,Gao, Yuanyuan,Zhao, Shuang,Ao, Changjin,Yang, Hongjian,Liu, Juxiong,Liu, Guowen,Han, Wenyu,Wang, Yuping,Lei, Liancheng Korean Society for Molecular and Cellular Biology 2016 Molecules and cells Vol.39 No.5

During the lactation cycle of the bovine mammary gland, autophagy is induced in bovine mammary epithelial cells (BMECs) as a cellular homeostasis and survival mechanism. Interferon gamma ($IFN-{\gamma}$) is an important antiproliferative and apoptogenic factor that has been shown to induce autophagy in multiple cell lines in vitro. However, it remains unclear whether $IFN-{\gamma}$ can induce autophagy and whether autophagy affects milk synthesis in BMECs. To understand whether $IFN-{\gamma}$ affects milk synthesis, we isolated and purified primary BMECs and investigated the effect of $IFN-{\gamma}$ on milk synthesis in primary BMECs in vitro. The results showed that $IFN-{\gamma}$ significantly inhibits milk synthesis and that autophagy was clearly induced in primary BMECs in vitro within 24 h. Interestingly, autophagy was observed following $IFN-{\gamma}$ treatment, and the inhibition of autophagy can improve milk protein and milk fat synthesis. Conversely, upregulation of autophagy decreased milk synthesis. Furthermore, mechanistic analysis confirmed that $IFN-{\gamma}$ mediated autophagy by depleting arginine and inhibiting the general control nonderepressible-2 kinase (GCN2)/eukaryotic initiation factor $2{\alpha}$ ($eIF2{\alpha}$) signaling pathway in BMECs. Then, it was found that arginine supplementation could attenuate $IFN-{\gamma}$-induced autophagy and recover milk synthesis to some extent. These findings may not only provide a novel measure for preventing the $IFN-{\gamma}$-induced decrease in milk quality but also a useful therapeutic approach for $IFN-{\gamma}$-associated breast diseases in other animals and humans.

Structural-based Screening of L-phenylglycine Aminotransferase using L-phenylalanine as the Optimal Amino Donor: Recycling of L-phenylalanine to Produce L-phenylglycine

Shuang Ping Liu,Rui Xia Liu,Jian Mao,Liang Zhang,Zhongyang Ding,Zhenghua Gu,Gui-Yang Shi 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.1

The aproteinogenic amino acid, L-phenylglycine, is an important side chain building block for some drugs. It would be of great commercial and environmental value to biocatalyse L-phenylalanine to L-phenylglycine, and thus replace the organic synthesis method. To produce Lphenylglycine from L-phenylalanine, an L-phenylglycine aminotransferase was screened and characterized. HpgTAO showed high homology to α-aminoadipate aminotransferase. The L-phenylalanine binding site was near the residues S26, R401, N201, and G46 in HpgTAO, and L-phenylalanine formed a hydrogen bond with Asn20, which was similar to the substrate binding mechanism of α-aminoadipate aminotransferase. HpgTAO showed increased activity in alkalescent environment below 40°C. The kinetic analysis showed that L-phenylalanine had the highest affinity to HpgTAO, which ensured the recycle biosynthesis of Lphenylglycine from L-phenylalanine. To date, it was the only aminotransferase using L-phenylalanine as an optimal amino donor. The L-phenylglycine biocatalysis operon was also constructed by co-expressing the hmaS, hmo and hpgT by a single plasmid. The first in vitro conversion of Lphenylalanine to L-phenylglycine was achieved by directly using the L-phenylalanine fermentation broth as the raw material.

Halomonas alkalitolerans sp. nov., a Novel Moderately Halophilic Bacterium Isolated from Soda Meadow Saline Soil in Daqing, China

Shuang Wang,Qian Yang,Zhi-Hua Liu,Lei Sun,Dan Wei,Jun-Zheng Zhang,Jin-Zhu Song,Yun Wang,Jia Song,Jin-Xia Fan,Xian-Xin Meng,Wei Zhang 한국미생물학회 2011 The journal of microbiology Vol.49 No.1

A moderately halophilic bacterial strain 15-13^T, which was isolated from soda meadow saline soil in Daqing City, Heilongjiang Province, China, was subjected to a polyphasic taxonomic study. The cells of strain 15-13^T were found to be Gram-negative, rod-shaped, and motile. The required growth conditions for strain 15-13^T were: 1-23% NaCl (optimum, 7%), 10-50°C (optimum, 35°C), and pH 7.0-11.0 (optimum, pH 9.5). The predominant cellular fatty acids were C18:1 ω7c (60.48%) and C16:0 (13.96%). The DNA G+C content was 67.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain 15-13^T clustered within a branch comprising species of the genus Halomonas. The closest phylogenetic neighbor of strain 15-13^T was Halomonas pantelleriensis DSM 9661^T (98.9% 16S rRNA gene sequence similarity). The level of DNA-DNA relatedness between the novel isolated strain and H. pantelleriensis DSM 9661^T was 33.8%. On the basis of the phenotypic and phylogenetic data, strain 15-13^T represents a novel species of the genus Halomonas, for which the name Halomonas alkalitolerans sp. nov. is proposed. The type strain for this novel species is 15-13^T (=CGMCC 1.9129^T =NBRC 106539^T).

Focus Improvement of High-Squint SAR Based on Azimuth Dependence of Quadratic Range Cell Migration Correction

Zhang, Shuang-Xi,Xing, Meng-Dao,Xia, Xiang-Gen,Zhang, Lei,Guo, Rui,Bao, Zheng IEEE 2013 IEEE geoscience and remote sensing letters Vol.10 No.1

<P>In this letter, we discuss the problem that linear range cell walk correction in the azimuth time domain may cause space variation along the azimuth not only to the quadratic phase but also to the quadratic range cell migration (QRCM) under the conditions of high resolution and large scene along the azimuth. Moreover, an algorithm is proposed to deal with this problem. The proposed algorithm adopts the azimuth space variation filtering in the range frequency domain. In addition, the range-dependence component of QRCM is corrected by linear chirp scaling, and the unified QRCM can be corrected in the 2-D frequency domain. The proposed algorithm, without interpolation, can be easily implemented by integrating with motion compensation for image processing. Simulation and airborne strip-map real data show the accuracy and efficiency of the proposed algorithm.</P>

The Specific Case Analysis of Biomineralization Induced by Sulfate Reducing Bacteria

( Hongwei Liu ),( Shuang Qin ),( Chaoyang Fu ),( Fei Xiao ),( Deli Wang ),( Xia Han ),( Tianli Wang ),( Hongfang Liu ) 한국부식방식학회(구 한국부식학회) 2017 Corrosion Science and Technology Vol.16 No.6

The effects of sulfate reducing bacteria (SRB) on the corrosion and scaling of the Q235 carbon steel has been investigated in the simulated sewage water and oil field gathering pipelines production water, using scanning electron microscopy (SEM), energy dispersive x-ray spectrometry (EDS), and three-dimensional stereoscopic microscope. Results indicated that the concentration of SRB reached the maximum value on the ninth day in simulated sewage water with a large amount of scaling on the surface of specimen. In oil field gathering pipelines, a large amount of scaling and mineralization of mineral salts and thick deposition of extracellular polymeric substance (EPS) layers were also observed on the surface of specimen. The thickness of biofilm was about 245 μm within 30 days. After adding microbicides, the thickness of corrosion products film was only up to 48 - 106 μm within 30 days, suggesting that SRB could induce biomineralization. Under-deposit corrosion morphology was uniform in the absence of microbicides while local corrosion was observed in the presence of microbicides.

Silencing of Twist Expression by RNA Interference Suppresses Epithelial-mesenchymal Transition, Invasion, and Metastasis of Ovarian Cancer

Wang, Wen-Shuang,Yang, Xing-Sheng,Xia, Min,Jiang, Hai-Yang,Hou, Jian-Qing Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Purpose: This study aimed to explore the role of the Twist gene in the epithelial-mesenchymal transition of ovarian cancer. Methods: An RNA interference plasmid expressing a small interfering RNA (siRNA)-targeting Twist (Twist siRNA vector) was designed, constructed, and transfected into the human ovarian cancer cell line A2780. Transfection efficiency was assessed under a fluorescence microscope. Changes in the expression of Twist mRNA in A2780 after transfection with the pGenesil Twist shRNA plasmid were analyzed through RT-PCR. MTT assays and adhesion experiments were applied to determine changes in proliferation and adhesion ability of A2870 after transfection with the Twist shRNA plasmid. Changes in the expression of the E-cadherin and N-cadherin proteins in A2780 after transfection with the Twist shRNA plasmid were analyzed using Western blotting. Result: The restructuring plasmid pGenesil-Twist shRNA was constructed successfully. After 48 h of culture, 80% of the cells expressed high-intensity GFP fluorescence and stability. The expression of Twist decreased significantly after the transfection of the Twist shRNA plasmid (P<0.05). Proliferation of the transfected Twist shRNA cells showed no difference with that of the A2780-nontransfection or A2780-si-control groups (P>0.05) but the adhesion ability of A2780 decreased dramatically (P<0.05). Expression of the E-cadherin protein increased, whereas that of the N-cadherin protein decreased compared with that in the A2780-nontransfection or A2780-si-control groups (P<0.05). Conclusion: Twist is essential for epithelial-mesenchymal transition, invasion, and metastasis of ovarian cancer.

A Flow Analysis Framework for Traffic Video

Bai, Lu-Shuang,Xia, Ying,Lee, Sang-Chul Korea Spatial Information System Society 2009 한국공간정보시스템학회 논문지 Vol.11 No.2

The fast progress on multimedia data acquisition technologies has enabled collecting vast amount of videos in real time. Although the amount of information gathered from these videos could be high in terms of quantity and quality, the use of the collected data is very limited typically by human-centric monitoring systems. In this paper, we propose a framework for analyzing long traffic video using series of content-based analyses tools. Our framework suggests a method to integrate theses analyses tools to extract highly informative features specific to a traffic video analysis. Our analytical framework provides (1) re-sampling tools for efficient and precise analysis, (2) foreground extraction methods for unbiased traffic flow analysis, (3) frame property analyses tools using variety of frame characteristics including brightness, entropy, Harris corners, and variance of traffic flow, and (4) a visualization tool that summarizes the entire video sequence and automatically highlight a collection of frames based on some metrics defined by semi-automated or fully automated techniques. Based on the proposed framework, we developed an automated traffic flow analysis system, and in our experiments, we show results from two example traffic videos taken from different monitoring angles.