The Relationship between Senescence and Ca²⁺-ATPase Activity of Microsomal Membrane and Lipid Peroxidation in Postharvest Peach Fruits

GuanJun Feng,FanXiu Cai,DouShi Juan,ZhangJi Shu,LiGuang Min 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

STING Negatively Regulates Double-Stranded DNA-Activated JAK1-STAT1 Signaling via SHP-1/2 in B Cells

Dong, Guanjun,You, Ming,Ding, Liang,Fan, Hongye,Liu, Fei,Ren, Deshan,Hou, Yayi Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.5

Recognition of cytosolic DNA initiates a series of innate immune responses by inducing IFN-I production and subsequent triggering JAK1-STAT1 signaling which plays critical roles in the pathogenesis of infection, inflammation and autoimmune diseases through promoting B cell activation and antibody responses. The stimulator of interferon genes protein (STING) has been demonstrated to be a critical hub of type I IFN induction in cytosolic DNA-sensing pathways. However, it still remains unknown whether cytosolic DNA can directly activate the JAK1-STAT1 signaling or not. And the role of STING is also unclear in this response. In the present study, we found that dsDNA directly triggered the JAK1-STAT1 signaling by inducing phosphorylation of the Lyn kinase. Moreover, this response is not dependent on type I IFN receptors. Interestingly, STING could inhibit dsDNA-triggered activation of JAK1-STAT1 signaling by inducing SHP-1 and SHP-2 phosphorylation. In addition, compared with normal B cells, the expression of STING was significantly lower and the phosphorylation level of JAK1 was significantly higher in B cells from MRL/lpr lupus-prone mice, highlighting the close association between STING low-expression and JAK1-STAT1 signaling activation in B cells in autoimmune diseases. Our data provide a molecular insight into the novel role of STING in dsDNA-mediated inflammatory disorders.

Research on the Security Threats and Strategy in Smart Grid Application

Ding, Guanjun,Fan, Bangkui,Long, Teng,Lan, Haibin,Wang, Jing,Chen, Zhiyong The Korean Institute of Electrical Engineers 2014 The Journal of International Council on Electrical Vol.4 No.3

The smart grid is evolving rapidly from a relatively isolated environment to an opened one. The adoption of information and communication technologies can make greater connectivity and interoperability between components. However, the increased connectivity also brings the challenge to security. First of all, in allusion to the current study on security threats to smart grid simple and deficient, the paper induces and analyzes it thoroughly, which can also correct some misunderstanding in a certain degree, from the view of system level, services, confidentiality and so on. Secondly, based on the analysis of security threats, the paper constructs the security strategy for smart grid. It consists of four steps, which are discussed detailedly one by one. It can provide the protection effectively. Finally, relevant conclusions are made.

Synthesis of High-Performance Polymers via Copper-Catalyzed Amination of Dibromoarenes with Primary Aromatic Ether Diamines

Zhenfang Shang,Guanjun Chang,Li Yang 한국고분자학회 2015 Macromolecular Research Vol.23 No.10

In this paper, we introduce three high-performance polymers with similar structures, poly(imino ether ketone) (PIEK)s, which are synthesized by the ligand free copper-catalyzed C-N cross coupling reaction of aryl halides and primary aromatic diamines at moderate temperature. The influence of the solvents, base, temperature, and catalyst ligands on the polycondensation reaction is investigated. The structures of the polymers are characterized by means of 1H NMR spectroscopy, FTIR spectrometer and elemental analyses, and the results show a good agreement with the proposed structure. They all exhibit high glass transition temperature (Tg>170 oC), good thermal stability with high decomposition temperature (Td,5%>440 oC), and an excellent solubility in most organic solvents. In view of its good thermal stability and solubility, PIEK-1 foam with low density, 96 mg/cm3, is prepared via thermal induced phase separation and freeze-drying technology. The PIEK-1 foam possesses higher thermal stability than that of basal PIEK-1 (Td,5%>465 oC). Furthermore, due to intermolecular hydrogen bonds of the polymers, the achieved foam exhibits good mechanical property.

STING Negatively Regulates Double-Stranded DNA-Activated JAK1-STAT1 Signaling via SHP-1/2 in B Cells

Yayi Hou,Guanjun Dong,Ming You,Liang Ding,Hongye Fan,Fei Liu,Deshan Ren 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.5

Recognition of cytosolic DNA initiates a series of innate immune responses by inducing IFN-I production and subsequent triggering JAK1-STAT1 signaling which plays critical roles in the pathogenesis of infection, inflammation and autoimmune diseases through promoting B cell activation and antibody responses. The stimulator of interferon genes protein (STING) has been demonstrated to be a critical hub of type I IFN induction in cytosolic DNA-sensing pathways. However, it still remains unknown whether cytosolic DNA can directly activate the JAK1-STAT1 signaling or not. And the role of STING is also unclear in this response. In the present study, we found that dsDNA directly triggered the JAK1-STAT1 signaling by inducing phosphorylation of the Lyn kinase. Moreover, this response is not dependent on type I IFN receptors. Interestingly, STING could inhibit dsDNA-triggered activation of JAK1-STAT1 signaling by inducing SHP-1 and SHP-2 phosphorylation. In addition, compared with normal B cells, the expression of STING was significantly lower and the phosphorylation level of JAK1 was significantly higher in B cells from MRL/lpr lupus-prone mice, highlighting the close association between STING low-expression and JAK1-STAT1 signaling activation in B cells in autoimmune diseases. Our data provide a molecular insight into the novel role of STING in dsDNA-mediated inflammatory disorders.

Synthesis and Characterization of Poly(N-arylenebenzimidazole ketone ketone)s

Yewei Xu,Jie Tang,Guanjun Chang,Fanghua Zhu,Xuan Luo,Lin Zhang 한국고분자학회 2013 Macromolecular Research Vol.21 No.6

Poly(N-arylenebenzimidazole ketone ketone)s (PNABIKKs) consisting of m- and p-phenylene linkages have been synthesized by nucleophilic aromatic substitution from bis(benzimidazolyl) derivatives containing sulfonyl,carbonyl, and ether groups with activated aromatic difluorides in sulfolane at 210 oC in the presence of anhydrous potassium carbonate. The structures of the polymers were characterized by means of Fourier tramsfom infrared (FTIR), proton nuclear magnetic resonance (1H NMR) spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) measurements demonstrated that polymers had high glass transition temperatures (Tg>220 oC) and good thermal stability with high decomposition temperatures (TD>480 oC). These novel polymers also showed good solubility.

Simulation Analysis on Seismic Performance of Assembled Composite Energy Dissipation Pipe Joint

Jianpeng Sun,Yingbiao Jiang,Guanjun Lv,Kai Liu,Ju Zhao 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.3

Based on the seismic ductility design concept, a kind of assembled composite energy dissipation pipe joint with rapid repair after the earthquake was proposed. We established the fi nite element models of assembled composite energy dissipation pipe joints with the 24 diff erent structural parameters, and carried out the low reversed cyclic loading simulation test. The strain cloud diagram, hysteretic curve, skeleton curve, stiff ness degradation curve and energy dissipation capacity curve of the pipe joints were obtained. The structural parameters’ infl uence on the performance indexes of the pipe joints was analyzed. The results show that the proposed assembled composite energy dissipation pipe joint has good ductility and energy dissipation capacity. The replacement of peripheral energy dissipation steel plate is simple and fast, and the mechanical properties can be restored after replacement. The diameter thickness ratio of peripheral energy dissipating steel pipe has more signifi cant impact on the seismic performance of the connecting parts. With the increase of the diameter thickness ratio of the peripheral energy dissipating steel pipe, the energy dissipation capacity gradually increases. The ratio of height to thickness has less eff ect on the seismic performance of the model, and the initial stiff ness and energy dissipation capacity of the model are signifi cantly enhanced after the stiff ened steel pipe is installed outside.

Trichoderma reesei Sch9 and Yak1 regulate vegetative growth, conidiation, and stress response and induced cellulase production

Xinxing Lv,Weixin Zhang,Guanjun Chen,Weifeng Liu 한국미생물학회 2015 The journal of microbiology Vol.53 No.4

Protein kinases are key players in controlling many basiccellular processes in almost all the organisms via mediatingsignal transduction processes. In the present study, we characterizedthe cellulolytic Trichoderma reesei orthologs ofSaccharomyces cerevisiae Sch9 and Yak1 by sequence alignmentand functional analysis. The T. reesei Trsch9Δ andTryak1Δ mutant strains displayed a decreased growth rateon different carbon sources and produced less conidia. Theabsence of these two kinases also resulted in different butabnormal polarized apical growth as well as sensitivity tovarious stresses. In addition, disruption of the genes Trsch9 orTryak1 resulted in perturbation of cell wall integrity. Interestingly,while the induced production of cellulases was slightlycompromised in the Trsch9Δ strain, the extracellular productionof cellulases was significantly improved in the absenceof Yak1. The results indicate that TrSch9 and TrYak1play an important role in filamentous growth, stress responseand induced production of cellulases in T. reesei.

Antioxidant and Antigenotoxic Activities of Ethanol Extracts from Rhus chinensis Mill Leaves

Zhenyu Qiu,Mingli Tang,Guanjun Deng,Hao Yang,Xuan Zhang,Shengwei Huang,Lifang Wu 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.4

Ethanol extracts were obtained from Rhuschinensis Mill (RCM) leaves and used for antioxidant andantigenotoxic activity assays. IC50 values in DPPH assayswere 15.96, 18.83, 20.43, 27.93, 37.43, 46.21, and 141.84μg/mL for TPP, IPE, LLE, Vc, CE, BHT, and Trolox. Similar results were obtained using ABTS and FRAPassays. In vivo testing showed strong antioxidant activitiesthat were positively correlated with polyphenol contents. Leaf tissue contained abundant polyphenols, and more than10 phenolic compounds were detected in extracts. Quantitative results showed that quercetin-3-rhamnoside(26.4±0.76 mg/g of extract) was the most abundantingredient, followed by hyperoside (15.2±0.42 mg/g ofextract), quercetin (1.5±0.07mg/g of extract), and kaempferol(0.48±0.05 mg/g of extract). This study increases theknowledge for possible uses of forest by-products as asubstitute for gallnuts.

Purification and Structure Analysis of Mycolic Acids in Corynebacterium glutamicum

Yang Yang,Feng Shi,Guanjun Tao,Xiaoyuan Wang 한국미생물학회 2012 The journal of microbiology Vol.50 No.2

Corynebacterium glutamicum is widely used for producing amino acids. Mycolic acids, the major components in the cell wall of C. glutamicum might be closely related to the secretion of amino acids. In this study, mycolic acids were extracted from 5 strains of C. glutamicum, including ATCC 13032,ATCC 13869, ATCC 14067, L-isoleucine producing strain IWJ-1, and L-valine producing strain VWJ-1. Structures of these mycolic acids were analyzed using thin layer chromatography and electrospray ionization mass spectrometry. More than twenty molecular species of mycolic acid were observed in all 5 strains. They differ in the length (20–40carbons) and saturation (0–3 double bonds) of their constituent fatty acids. The dominant species of mycolic acid in every strain was different, but their two hydrocarbon chains were similar in length (14–18 carbons), and the meromycolate chain usually contained double bonds. As the growth temperature of cells increased from 30°C to 34°C, the proportion of mycolic acid species containing unsaturated and shorter hydrocarbon chains increased. These results provide new information on mycolic acids in C. glutamicum,and could be useful for modifying the cell wall to increase the production of amino acids.