An Improved Method for Extracting Bacteria from Soil for High Molecular Weight DNA Recovery and BAC Library Construction

Juan Liu,Jingquan Li,Li Feng,Hui Cao,Zhongli Cui 한국미생물학회 2010 The journal of microbiology Vol.48 No.6

Separation of bacterial cells from soil is a key step in the construction of metagenomic BAC libraries with large DNA inserts. Our results showed that when combined with sodium pyro-phosphate and homogenization for soil dispersion, sucrose density gradient centrifugation (SDGC) was more effective at separating bacteria from soil than was low speed centrifugation (LSC). More than 70% of the cells, along with some soil colloids,were recovered with one round of centrifugation. A solution of 0.8% NaCl was used to resuspend these cell and soil pellets for purification with nycodenz density gradient centrifugation (NDGC). After purification,more than 30% of the bacterial cells in the primary soil were extracted. This procedure effectively removed soil contamination and yielded sufficient cells for high molecular weight (HMW) DNA isolation. Ribosomal intergenic spacer analysis (RISA) showed that the microbial community structure of the extracted cells was similar to that of the primary soil, suggesting that this extraction procedure did not significantly change the the soil bacteria community structure. HMW DNA was isolated from bacterial cells extracted from red soil for metagenomic BAC library construction. This library contained DNA inserts of more than 200 Mb with an average size of 75 kb.

Study on the Recycling of Nuclear Graphite after Micro-Oxidation

Liu, Juan,Wang, Chen,Dong, Limin,Liang, Tongxiang Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.1

In this paper, a feasible strategy for the recycling of nuclear graphite is reported, based on the formation mechanism and the removal of carbon-14 by micro-oxidation. We investigated whether ground micro-oxidation graphite could be used as a filler to make new recycled graphite and which graphite/pitch coke ratio will give the recycled graphite outstanding properties (e.g., apparent density, flexural strength, compressive strength, and tensile strength). According to the existing properties of nuclear graphite, the ratio of graphite to pitch coke should not exceed 3. The recycled reactor graphite has been proven superior in density, strength, and thermal conductivity. The micro-oxidation process enhances the strength of the recycled graphite because there are more pores and unsmooth surfaces on the oxidized graphite particles, which is beneficial for the access of the pitch binder and leads to efficient joint adhesion among the graphite particles.

Antibacterial Polyketides from the Jellyfish-Derived Fungus <i>Paecilomyces variotii</i>

Liu, Juan,Li, Famei,Kim, Eun La,Li, Jian Lin,Hong, Jongki,Bae, Kyung Sook,Chung, Hae Young,Kim, Hyung Sik,Jung, Jee H. American Chemical Society and American Society of 2011 Journal of natural products Vol.74 No.8

<P>Four new polyketides (<B>1</B>–<B>4</B>) were isolated from the fungus <I>Paecilomyces variotii</I>, which was derived from the jellyfish <I>Nemopilema nomurai</I>. The planar structures and relative configurations of these polyketides were elucidated on the basis of spectroscopic analyses, including 2D NMR experiments. The compounds showed inhibitory activity against pathogenic bacteria including methicillin-resistant <I>Staphylococcus aureus</I> 3089 and multi-drug-resistant <I>Vibrio parahemolyticus</I> 7001 with MIC values in the range 5–40 μg/mL.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jnprdf/2011/jnprdf.2011.74.issue-8/np200350b/production/images/medium/np-2011-00350b_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/np200350b'>ACS Electronic Supporting Info</A></P>

Effects of Ribosomal Protein L39-L on the Drug Resistance Mechanisms of Lung Cancer A549 Cells

Liu, Hong-Sheng,Tan, Wen-Bin,Yang, Ning,Yang, Yuan-Yuan,Cheng, Peng,Liu, Li-Juan,Wang, Wei-Jie,Zhu, Chang-Liang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.7

Background: Cancer is a major threat to the public health whether in developed or in developing countries. As the most common primary malignant tumor, the morbidity and mortality rate of lung cancer continues to rise in recent ten years worldwide. Chemotherapy is one of the main methods in the treatment of lung cancer, but this is hampered by chemotherapy drug resistance, especially MDR. As a component of the 60S large ribosomal subunit, ribosomal protein L39-L gene was reported to be expressed specifically in the human testis and human cancer samples of various tissue origins. Materials and Methods: Total RNA of cultured drug-resistant and susceptible A549 cells was isolated, and real time quantitative RT-PCR were used to indicate the transcribe difference between amycin resistant and susceptible strain of A549 cells. Viability assay were used to show the amycin resistance difference in RPL39-L transfected A549 cell line than control vector and null-transfected A549 cell line. Results: The ribosomal protein L39-L transcription level was 8.2 times higher in drug-resistant human lung cancer A549 cell line than in susceptible A549 cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells showed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation. Conclusions and Implications for Practice: The ribosomal protein L39-L gene may have effects on the drug resistance mechanism of lung cancer A549 cells.

A Ringed Dwarf LINER 1 Galaxy Hosting an Intermediate-mass Black Hole with Large-scale Rotation-like ${\rm{H}}\alpha $ Emission

Liu, Wen-Juan,Qian, Lei,Dong, Xiao-Bo,Jiang, Ning,Lira, Paulina,Cai, Zheng,Wang, Feige,Yang, Jinyi,Xiao, Ting,Kim, Minjin American Astronomical Society 2017 The Astrophysical journal Vol.837 No.2

<P>We report the discovery of a 20 kpc sized H alpha emission in SDSS J083803.68+540642.0, a ringed dwarf galaxy (M-V = -17.89 mag) hosting an accreting intermediate-mass black hole at z = 0.02957. Analysis of the Hubble Space Telescope images indicates that it is an early-type galaxy with a featureless low-surface brightness disk (mu(0) = 20.39 mag arcsec(-2) in the V band) and a prominent, relatively red bulge (V - I = 2.03, R-e = 0.28 kpc or 0 48) that accounts for approximate to 81% of the total light in the I band. A circumgalactic ring of a diameter 16 kpc is also detected, with a disperse shape on its south side. The optical emission lines reveal the nucleus to be a broad-line LINER. Our MMT longslit observation indicates that the kinematics of the extended H alpha emission is consistent with a rotational gaseous disk, with a mean blueshifted velocity of 162 km s(-1) and mean redshifted velocity of 86 km s(-1). According to our photoionization calculations, the large-scale H alpha emission is unlikely to be powered by the central nucleus or by hot evolved (post-AGB) stars interspersed in the old stellar populations, but by in situ star formation; this is vindicated by the line-ratio diagnostic of the extended emission. We propose that both the ring and large-scale H alpha-emitting gas are created by the tidal accretion in a collision-and then merger-with a gas-rich galaxy of a comparable mass.</P>

Bacillus oceani sp. nov., a new slightly halophilic bacterium, isolated from a deep sea sediment environment

Liu, Yu-Juan,Long, Li-Juan,Huang, Xiao-Fang,You, Zhi-Qing,Wang, Fa-Zuo,Li, Jie,Kim, Chang-Jin,Tian, Xin-Peng,Zhang, Si Springer-Verlag 2013 Antonie van Leeuwenhoek Vol.104 No.5

New Alkoxyglycerols from the Jellyfish Nemopilema nomurai

Juan Liu,Jongki Hong,김은라,Eun Sook Yoo,김의경,Won Duk Yoon,정지형,Famei Li 한국생약학회 2009 Natural Product Sciences Vol.15 No.2

The great economic and social damage caused by unusual explosion of jellyfish population has attracted the attention of researchers. A chemical study on the bioactive components of the giant jellyfishNemopilema nomurai led to the isolation of two new (1 and 2) and three known alkoxyglycerols (3 - 5), alongwith known monoglycerides (6 - 7) and fatty acids. Based on NMR and MS data, the structures of compounds 1and 2 were elucidated as 1-O-[(Z)-tetradec-3-enyl]-sn-glycerol and 1-O-[(Z)-octadec-10-enyl]-sn-glycerol, respectively. The absolute configurations of compounds 1 - 7 were determined by comparison of specific opticalrotation values with those reported. The isolated compounds were evaluated for suppressive effect on the proinflammatorymediators (NO, IL-6, and TNF-α) in murine macrophage cells. However, they were found inactiveupto the concentration of 100 µM.

Activation of TLR7-mediated autophagy increases epileptic susceptibility via reduced KIF5A-dependent GABAA receptor transport in a murine model

Liu Jing,Ke Pingyang,Guo Haokun,Gu Juan,Liu Yanling,Tian Xin,Wang Xuefeng,Xiao Fei 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

The pathophysiological mechanisms underlying epileptogenesis are poorly understood but are considered to actively involve an imbalance between excitatory and inhibitory synaptic transmission. Excessive activation of autophagy, a cellular pathway that leads to the removal of proteins, is known to aggravate the disease. Toll-like receptor (TLR) 7 is an innate immune receptor that regulates autophagy in infectious and noninfectious diseases. However, the relationship between TLR7, autophagy, and synaptic transmission during epileptogenesis remains unclear. We found that TLR7 was activated in neurons in the early stage of epileptogenesis. TLR7 knockout significantly suppressed seizure susceptibility and neuronal excitability. Furthermore, activation of TLR7 induced autophagy and decreased the expression of kinesin family member 5 A (KIF5A), which influenced interactions with γ-aminobutyric acid type A receptor (GABAAR)-associated protein and GABAARβ2/3, thus producing abnormal GABAAR-mediated postsynaptic transmission. Our results indicated that TLR7 is an important factor in regulating epileptogenesis, suggesting a possible therapeutic target for epilepsy.

Effect of an Antagonistic Peptide of CCR5 on the Expression of Autophagy-related Genes and β-Arrestin 2 in Lung Tissues of Asthmatic Mice

Liu Juan,Liang Rongrong,Huang Huarong,Zhang Yingli,Xie Aicen,Zhong Yingqiang 대한천식알레르기학회 2021 Allergy, Asthma & Immunology Research Vol.13 No.1

Purpose: The mechanisms of CC chemokine receptor 5 (CCR5) in the process of autophagy remain unknown. In this study, we examined the role of HY peptide, which is an antagonistic peptide specifically binding the second extracellular loop of CCR5, in the expression of autophagy genes and β-arrestin 2 in lung tissues of asthmatic mice. Methods: Experimental asthmatic mice were treated with HY peptide and dexamethasone sodium phosphate (Dex). Airway inflammation, autophagy-related genes, autophagic vacuoles (AVs) and β-arrestin 2 were examined in lung tissues, and the correlation between β-arrestin 2 and LC3 expression was assessed. Results: HY peptide and Dex treatments alleviate airway inflammation. The expression of autophagy-related genes, such as BECN1, ATG5 and LC3, was decreased in the lung tissues of the asthmatic mice. However, HY peptide and Dex treatments increased the expression of these genes as well as the formation of AVs. Additionally, the expression of the β-arrestin 2 protein was significantly increased in the HY peptide-treated group, and positive cells expressing β-arrestin 2 were mainly located in the membrane and cytoplasm of bronchial epithelial cells. The β-arrestin 2 expression was positively correlated with the expression of LC3 in the model and HY peptide-treated groups. Conclusions: HY peptide inhibits airway inflammation, autophagic dysfunction exists in asthmatic mice, and targeting HY peptide increases the expression of autophagy-related genes. Thus, β-arrestin 2 may participate in the mechanisms underlying these processes.

A New 3D Statistical Parameter for Determining Roughness of Joint Surfaces Considering Shear Direction and Asperity Features

Juan Liu,Feng Gao,Yan Xing,Wenqi Zheng,Yun Bai 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.11

The engineering rock mass is a multi-fracture body crisscrossed by geologic structure planes, and its safety is affected by the rock joints' mechanical properties and morphological features. The joint roughness coefficient (JRC) is a vital characterization method to describe joint surface roughness. Its precise quantization is a crucial factor in predicting shear strength. However, JRCin recent research did not reflect the directional effect of the joint morphology. A new 3D roughness parameter WAD (weighted apparent dip) was proposed to estimate JRC based on the apparent dip angle of the contact unit. The proposed parameter comprehensively reflects the contribution of shear direction and asperity features to the roughness. Based on the ten standard roughness profiles, we investigated the directionality of the WAD and studied the influence of the sampling interval (Sai) on WAD and their correlation with JRC. And the practicability of WAD in evaluating JRC was well verified by the comparison between the indoor test and calculated results with different roughness and shear directions, and the results showed that WAD could accurately estimate the shear strength of the joint rock.