An extremely thermostable maltogenic amylase from <i>Staphylothermus marinus</i>: <i>Bacillus</i> expression of the gene and its application in genistin glycosylation

Li, Xiaolei,Wang, Yujuan,Park, Jong-Tae,Gu, Liwei,Li, Dan Elsevier 2018 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.107 No.1

<P><B>Abstract</B></P> <P>The most extremely thermostable maltogenic amylase (SMMA) from archaeon <I>Staphylothermus marinus</I> has many potential applications in food processing. To ensure safety of microbial origin, a recombinant plasmid containing the enzymic gene and a constitutive promoter AmyR2 was constructed, and then transformed into a GRAS microorganism <I>Bacillus subtilis</I>. The purified SMMA from the liquid cultures of <I>Bacillus</I> has a specific activity of 66.96U/mg, two times more than that from <I>Escherichia coli</I>. SMMA was further employed to catalyze the genistion glycosylation using γ-CD as both glucosyl donors and solubilizer. Glycosylated genistins with one to four additional α-glucosyls and a molar percentage of 69.87% in genistin reaction mixture were identified and quantified by HPLC–UV–MS. The glycosylated genistins at 0.2–1.2mM showed an enhanced DPPH free radical scavenging capacity. To our knowledge, this is the first report on the <I>Bacillus</I> expression of archaeal maltogenic amylase.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A fused gene of SMMA and a constitutive promoter AmyR2 was transformed into <I>B. subtilis</I>. </LI> <LI> Specific activity of purified SMMA from <I>B. subtilis</I> was two times more than that from <I>E. coli</I>. </LI> <LI> SMMA of safe microbial origin attached different number of glucosyls from γ-CD to genistin at 90°C. </LI> <LI> Glycosylated genistins showed an enhanced DPPH free radical scavenging capacity than genistin. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

In-situ photocrosslinked hydroxide conductive membranes based on photosensitive poly(arylene ether sulfone) block copolymers for anion exchange membrane fuel cells

He, Rui,Wen, Pushan,Zhang, Hai-Ning,Guan, Shumeng,Xie, Guangyong,Li, Li-Zhong,Lee, Myong-Hoon,Li, Xiang-Dan Elsevier 2018 Journal of membrane science Vol.556 No.-

<P><B>Abstract</B></P> <P>A series of photocrosslinkable multi-block poly(arylene ether sulfone) copolymers containing various block lengths of hydrophilic segments were synthesized. For comparison, a series of random poly(arylene ether) copolymers were also synthesized. The anion exchange membranes(AEMs) were fabricated and in-situ photocrosslinking was carried out by UV irradiation in a swollen state. The microphase-separated morphologies of the multi-block membranes were characterized by SAXS and TEM experiments, and the membrane properties were investigated by measuring ion exchange capacity (IEC), water uptake, water swelling ratio, ionic conductivity, methanol permeability and alkaline stability. IECs and water uptakes of the crosslinked multi-block membranes were in the range of 1.11–1.42 meq g<SUP>−1</SUP> and 14.36–31.01% at 20 °C, respectively. The hydroxide conductivity was in the range of 11.38–25.00 mS cm<SUP>−1</SUP> at 20 °C, and showed a maximum value of 178.77 mS cm<SUP>−1</SUP> at 100 °C. The multi-block membranes exhibited low methanol permeability (2.75 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>) at room temperature, which is one order of magnitude lower than that of Nafion® 117 (23.8 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>). The crosslinked membranes showed excellent dimensional stability and alkaline stability with only a slight decrease in ionic conductivity. All the multi-block membranes showed superior properties compared to their corresponding random copolymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multi-block poly(arylene ether sulfone) copolymers were synthesized for AEMs. </LI> <LI> <I>In-situ</I> photo-crosslinking was carried out by UV irradiation in hydrated states. </LI> <LI> The block copolymers exhibited hydrophilic/hydrophobic phase separated morphology. </LI> <LI> The block copolymers showed superior properties compare to the random copolymers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

NiCo₂O₄ nanostructure-decorated PAN/lignin based carbon nanofiber electrodes with excellent cyclability for flexible hybrid supercapacitors

Lei, Danyun,Li, Xiang-Dan,Seo, Min-Kang,Khil, Myung-Seob,Kim, Hak-Yong,Kim, Byoung-Suhk Elsevier 2017 Polymer Vol.132 No.-

<P><B>Abstract</B></P> <P>Nanostructured binary metal oxide-decorated carbon nanofibers (CNFs) were utilized as flexible electrodes for hybrid supercapacitor applications. Polyacrylonitrile (PAN)/lignin based carbon nanofibers (PAN/lignin CNFs) with different contents of lignin were prepared by electrospinning, stabilization and carbonization. Afterwards, the NiCo<SUB>2</SUB>O<SUB>4</SUB> oxides were deposited on the surface of CNFs by a facile hydrothermal method without any toxic reagents. SEM images confirmed that the NiCo<SUB>2</SUB>O<SUB>4</SUB> (nanosheet and nanoneedle) nanostructures were uniformly grown on the surface of every carbon fiber. The obtained flexible NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated PAN/lignin CNFs with 50% lignin (NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNF55) electrode exhibited high specific capacitance of the ∼1757 F g<SUP>−1</SUP> at 2 mA cm<SUP>−2</SUP> and excellent cyclability with ∼138% capacitance retention after 5000 cycles at 7 mA cm<SUP>−2</SUP>, suggesting lower internal resistance and higher electrochemical reversibility. In addition, the NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNFs//N-rGO solid state asymmetric supercapacitor devices were assembled in order to evaluate their practical applications. The NiCo<SUB>2</SUB>O<SUB>4</SUB>@CNF55//N-rGO asymmetric supercapacitor device exhibited a specific capacitance of 134.3 F g<SUP>−1</SUP> at a current densities of 1 A g<SUP>−1</SUP>, and possessed a maximum energy density of 47.75 Wh kg<SUP>−1</SUP> with a power density of 799.53 W kg<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PAN/lignin-based carbon fibers were prepared by electrospinning, stabilization and carbonization. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB> nanostructures were fabricated on PAN/lignin-based carbon nanofibers. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated fiber electrode exhibits highest specific capacitance of the ∼1757 Fg<SUP>-1</SUP>. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB>-decorated fiber electrode shows excellent capacitance retention of ∼138% after 5000 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Controlled synthesis of Co₂C nanochains using cobalt laurate as precursor: Structure, growth mechanism and magnetic properties

Zhang, Yajing,Zhu, Yuan,Wang, Kangjun,Li, Da,Wang, Dongping,Ding, Fu,Meng, Dan,Wang, Xiaolei,Choi, Chuljin,Zhang, Zhidong Elsevier 2018 Journal of magnetism and magnetic materials Vol.456 No.-

<P><B>Abstract</B></P> <P>Cobalt carbides (Co<SUB>2</SUB>C and Co<SUB>3</SUB>C) nanocomposites exhibit interesting hard magnetic property, controlled synthesis of individual phase facilitates to clarify the magnetism of each, but it is difficult to obtain the single phase. We present a new approach to address this issue via a polyol refluxing process, using cobalt laurate as the precursor. The single phase Co<SUB>2</SUB>C magnetic nanochains self-assembled by nanoparticles are synthesized. The precursor is the key factor for controlling the growth kinetics of the Co<SUB>2</SUB>C nanochains. Cobalt, instead of cobalt carbides, is produced if cobalt chloride, acetate and acetylacetonate replace cobalt laurate as the precursor, respectively. The evolution of the growth process has been studied. In the formation of Co<SUB>2</SUB>C, first fcc-Co produces, then it transforms into Co<SUB>2</SUB>C by carbon diffusion process, and the produced carbon first exists in disordered state and then a small amount of them transforms into graphite. Saturation magnetization (<I>Ms</I>) of Co<SUB>2</SUB>C nanochains obtained at 300 °C for 20, 60, and 180 min are 27.1, 18.9, and 10.9 emu g<SUP>−1</SUP>, respectively. The decrease of <I>Ms</I> caused by increasing carbon content, and the carbon content are much larger than the stoichiometric ratio value of Co<SUB>2</SUB>C (9.2 wt%). The Co<SUB>2</SUB>C nanochains have mesoporous pore of 3.8 nm and the specific surface area of 48.6 m<SUP>2</SUP> g<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Co<SUB>2</SUB>C magnetic nanochains are synthesized using cobalt laurate as the precursor in TEG. </LI> <LI> The precursor of cobalt laurate is the key factor for controlling the growth kinetics of Co<SUB>2</SUB>C nanochains. </LI> <LI> Ms of Co<SUB>2</SUB>C nanochains obtained at 300 °C for 20, 60, and 180 min are 27.1, 18.9, and 10.9 emu g<SUP>−1</SUP>, respectively. </LI> <LI> The decrease of Ms is caused by increasing carbon content with increasing reaction time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>We present a new approach to obtain single phase Co<SUB>2</SUB>C nanochains by using cobalt laurate as the precursor.</P> <P>[DISPLAY OMISSION]</P>

Fabrication of highly efficient coatable polarizer from tolane-based smectic reactive mesogen

He, Rui,Oh, Enche,Ye, Yang,Wen, Pushan,Jeong, Kwang-Un,Lee, Seung Hee,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2019 Polymer Vol.176 No.-

<P><B>Abstract</B></P> <P>This work is aimed to fabricate ultra-thin coatable polarizers on a single substrate based on “host-guest” effect between highly ordered smectic reactive mesogen (RM) and dichroic dye. We designed and synthesized a new tolane-based RM with a highly ordered smectic A phase at room temperature. Polymerizable “host-guest” mixture was formulated from the host RM, dichroic dye and additives, then spin-coated on a single substrate having an alignment layer. Subsequent in-situ photopolymerization by UV irradiation successfully resulted in a coatable polarizer with good polarizing properties. The fabricated coatable polarizer showed a dichroic ratio (DR) of 16.4 and a degree of polarization (DOP) of 99.3% with the thickness of 4 μm. The resulting coatable polarizer possessed a considerable solvent resistance, good thermal stability and robust mechanical properties. Moreover, we prepared a TN-mode LC cell by using the prepared coatable polarizers inside the cell (in-cell), in which the coatable polarizers acted as a polarizer and an alignment layer, simultaneously. The resulting TN cell with in-cell polarizers exhibited a decent electro-optical behavior. We believe that the coatable polarizer proposed in this study possesses practical application potential in ultra-thin LCDs or flexible OLEDs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Reactive mesogen with smectic A phase was synthesized for coatable polarizer. </LI> <LI> Coatable polarizer was fabricated on a single substrate by “host-guest” method. </LI> <LI> Coatable polarizer exhibits considerable optical property and excellent stability. </LI> <LI> LCD with in-cell structure was demonstrated by using the prepared coatable polarizer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Metabolic Regulation of Gene Expression by Histone Lysine β-Hydroxybutyrylation

Xie, Zhongyu,Zhang, Di,Chung, Dongjun,Tang, Zhanyun,Huang, He,Dai, Lunzhi,Qi, Shankang,Li, Jingya,Colak, Gozde,Chen, Yue,Xia, Chunmei,Peng, Chao,Ruan, Haibin,Kirkey, Matt,Wang, Danli,Jensen, Lindy M. Elsevier 2016 Molecular cell Vol.62 No.2

<P><B>Summary</B></P> <P>Here we report the identification and verification of a β-hydroxybutyrate-derived protein modification, lysine β-hydroxybutyrylation (Kbhb), as a new type of histone mark. Histone Kbhb marks are dramatically induced in response to elevated β-hydroxybutyrate levels in cultured cells and in livers from mice subjected to prolonged fasting or streptozotocin-induced diabetic ketoacidosis. In total, we identified 44 histone Kbhb sites, a figure comparable to the known number of histone acetylation sites. By ChIP-seq and RNA-seq analysis, we demonstrate that histone Kbhb is a mark enriched in active gene promoters and that the increased H3K9bhb levels that occur during starvation are associated with genes upregulated in starvation-responsive metabolic pathways. Histone β-hydroxybutyrylation thus represents a new epigenetic regulatory mark that couples metabolism to gene expression, offering a new avenue to study chromatin regulation and diverse functions of β-hydroxybutyrate in the context of important human pathophysiological states, including diabetes, epilepsy, and neoplasia.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lysine β-hydroxybutyrylation (Kbhb) is a new type of histone mark </LI> <LI> 44 non-redundant histone Kbhb sites are identified in human and mouse cells </LI> <LI> Histone Kbhb increases under starvation and STZ-induced ketoacidosis </LI> <LI> Starvation-induced H3K9bhb is associated with active gene expression </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

T-SPOT.TB for Detection of Tuberculosis Infection among Hematological Malignancy Patients and Hematopoietic Stem Cell Transplant Recipients

Qin, Li-Li,Wang, Qin-Rong,Wang, Qian,Yao, Hong,Wen, Li-Jun,Wu, Li-Li,Ping, Na-Na,Xie, Jun-Dan,Chen, Mei-Yu,Chen, Su-Ning Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

The diagnosis of latent Mycobacterium tuberculosis infection (LTBI) is recommended in hematological malignancy patients and before hematopoietic stem cell transplantation (Guidelines for the prevention and management of infectious complications of solid organ transplantation, 2004). Compared to traditional methods such as tuberculin skin test (TST), T-SPOT.TB has been shown to be more specific. In the present study we enrolled 536 patients for whom T-SPOT.TB was performed, among which 295 patients also received the TST test. The agreement (79%) between T-SPOT.TB and TST was poor (x=0.274, P<0.001). The patients with positive T-SPOT.TB results numbered 62 (11.6%), in which only 20 (48.8%) of the 41 receiving the TST test had positive results. A majority of the patients with T-SPOT.TB positive results had some other evidence ofTB, such as TB history, clinical symptoms and an abnormal chest CT scan. Active TB was found in 9 patients, in which 2 had negative TST results. We followed up the patients and no one developed active TB. Our study suggested that the T-SPOT.TB may be more useful for screening LTBI and active TB in hematological malignancy patients and hematopoietic stem cell transplant recipients than the TST test.

Syntheses and characterizations of high refractive index and low birefringence polyimides containing spirobifluorene in the side chain

Wen, Pushan,He, Rui,Li, Xiang-Dan,Lee, Myong-Hoon Elsevier 2017 Polymer Vol.117 No.-

<P><B>Abstract</B></P> <P>Two new diamine monomers having a spirobifluorene structure were synthesized through four steps, and polymerized with three different dianhydrides (PMDA, CBDA and 6FDA) to obtain six polyimides with spirobifluorene structure in the side chain. All the resulting polyimides displayed excellent thermal stability and high glass transition temperature. These polyimides synthesized from CBDA and 6FDA showed good solubility in typical organic solvents such as NMP, DMF and DMSO. Transparent and flexible cast films can be obtained from soluble polyimides or poly(amic acid) solution. The transmittance of polyimide films was higher than 90% in the visible wavelength range (higher than 80% in case of polyimide containing PMDA). The refractive indices of the result polyimides were found to be in the range from 1.6343 to 1.7007, which is higher than that of normal polymers. In addition, the optical birefringences of these polyimides were extremely low (0.0005–0.0014). The high refractive index and low birefringence of these polyimides as well as other descent physical and thermal properties would offer them possible applications in high performance optical materials such as flexible substrates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel polyimides containing 9,9’-spirobifluorene unit in the side chain were synthesized. </LI> <LI> The polyimides exhibit high thermal stability (T5 > 420 °C) with excellent optical properties such as high transparency (>90% at 400 nm), high refractive index (1.6342–1.7007) and low birefringence (0.0005–0.0014). </LI> <LI> The resulting polymer materials could be promising candidates for advanced optical applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Novel polyimides containing 9,9′-spirobifluorene unit in the side chain, which exhibit high transparency, high refractive index and low birefringence, have been developed as promising candidates for advanced optical applications.</P> <P>[DISPLAY OMISSION]</P>

Fabrication of dual-coated graphene oxide nanosheets by polypyrrole and poly(ionic liquid) and their enhanced electrorheological responses

Chen, Panpan,Cheng, Qianqian,Wang, Li-Min,Liu, Ying Dan,Choi, Hyoung Jin Elsevier 2019 Journal of industrial and engineering chemistry Vol.69 No.-

<P><B>Abstract</B></P> <P>A two-dimensional composite material, poly(ionic liquid)-modified graphene oxide/polypyrrole (GO/PPy/PIL) multilayered nanosheets, was fabricated and applied as a new electrorheological (ER) material. The morphological differences between the single- and dual-coated nanosheets were confirmed using scanning electron microscopy and transmission electron microscopy. Rheological properties measured using a rotational rheometer indicated that the GO/PPy/PIL composite nanosheets exhibited relatively high ER effect under a certain electric field strength than the GO/PPy nanosheets because of the universal PIL second coating. The dual-coated nanosheets also showed a higher applicable electric field strength due to the semiconductive properties of the thick PIL layer.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dual-coated composite GO/PPy/PIL nanosheets were fabricated. </LI> <LI> The PIL second coating significantly enhanced the ER effect of the nanosheets. </LI> <LI> GO/PPy/PIL exhibited higher available electric field strength than GO/PPy. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Homocysteine-targeting compounds as a new treatment strategy for diabetic wounds via inhibition of the histone methyltransferase SET7/9

Li Guodong,Li Dan,Wu Chun,Li Shengnan,Chen Feng,Li Peng,Ko Chung-Nga,Wang Wanhe,Lee Simon Ming-Yuen,Lin Ligen,Ma Dik-Lung,Leung Chung-Hang 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

In hypoxia and hyperglycemia, SET7/9 plays an important role in controlling HIF-1α methylation and regulating the transcription of HIF-1α target genes, which are responsible for angiogenesis and wound healing. Here, we report the Ir(III) complex Set7_1a bearing acetonitrile (ACN) ligands as a SET7/9 methyltransferase inhibitor and HIF-1α stabilizer. Interestingly, Set7_1a could engage SET7/9 and strongly inhibit SET7/9 activity, especially after preincubation with homocysteine (Hcy), which is elevated in diabetes. We hypothesize that Set7_1a exchanges ACN subunits for Hcy to disrupt the interaction between SET7/9 and SAM/SAH, which are structurally related to Hcy. Inhibition of SET7/9 methyltransferase activity by Set7_1a led to reduced HIF-1α methylation at the lysine 32 residue, causing increased HIF-1α level and recruitment of HIF-1α target genes that promote angiogenesis, such as VEGF, GLUT1, and EPO, in hypoxia and hyperglycemia. Significantly, Set7_1a improved wound healing in a type 2 diabetic mouse model by activating HIF-1α signaling and downstream proangiogenic factors. To our knowledge, this is the first Hcy-targeting iridium compound shown to be a SET7/9 antagonist that can accelerate diabetic wound healing. More importantly, this study opens a therapeutic avenue for the treatment of diabetic wounds by the inhibition of SET7/9 lysine methyltransferase activity.