Liu X.,Northeast Normal University |
Xu C.,Northeast Normal University |
Wang M.,Northeast Normal University |
Liu Q.,Northeast Normal University
Chemical Reviews | Year: 2015
A variety of C-CF3 bond forming reactions have been developed from various trifluoromethylating reagents, in the 30 years since trifluoromethyltrimethylsilane (TMSCF3) was synthesized from CF3Br (an ozone depleting compound) and trimethylsilyl chloride in 1984, TMSCF3 (Ruppert-Prakash reagent) has been and is still the most important CF3-centered nucleophilic trifluoromethylating reagent. Ruppert-Prakash reagent is now also a useful starting material for the synthesis of potassium (trifluoromethyl)- trimethoxyborate, the well-defined trifluoromethyl copper compounds, trifluoromethanesulfanylamides/trifluoromethanesulfanamides used in trifluoromethylthiolation, difluoromethyltriflate as a convenient source of difluorocarbene, (difluoromethyl)trimethylsilane (TMSCF2H) used in difluoromethylation reactions, Togni's reagents and related species as electrophilic trifluoromethylating reagents.
Shi H.L.,Northeast Normal University
IUBMB life | Year: 2011
The fibroblast growth factors (FGFs) are important for embryo development, wound healing, hematopoiesis, and angiogenesis. FGF-1, a member of FGF family, is involved in both receptor-dependent pathways and an intracrine pathway. Studies have recently shown that FGF-1 is overexpressed in the early stages of several kinds of cancer. Thus, FGF-1 is a candidate for cancer immunotargeting. To study the potential use of therapeutic antibodies against FGF-1, a monoclonal hybridoma 1C9 secreting monoclonal antibody specific for FGF-1 was developed. Then, a single-chain variable fragment (scFv) antibody was genetically engineered from hybridama 1C9. The binding of the scFv1C9 to the antigen FGF-1 was demonstrated by ELISA and immunoprecipitation assays. Functional analysis showed that the overexpressed scFv1C9 in MCF-7 cells targeted endogenous FGF-1 and prevented the translocation of FGF-1 into the nucleus, resulting in the blockade of the intracrine pathway of FGF-1, which caused the G1 arrest by p21 up-regulation. These results suggest that the generated scFv1C9 is an effective inhibitor of the intracrine pathway of FGF-1 and has a potential application as anti-tumoral agent in breast cancer. Copyright © 2011 Wiley Periodicals, Inc.
Su F.,Northeast Normal University |
Guo Y.,Northeast Normal University
Green Chemistry | Year: 2014
Biodiesel has emerged as one of the best potential renewable energy sources to replace current petroleum-based diesel. It is a sustainable, biodegradable and non-toxic diesel fuel substitute that can be easily produced through base- or acid-catalyzed esterification and transesterification reactions. The conventional base catalysts, although effective, are limited to use of refined vegetable oils, leading to impractical and uneconomical processes due to high feedstock cost and priority as food resources. Biodiesel production processes based on the use of acid catalysts are good alternatives to conventional processes because of their simplicity and the simultaneous promotion of esterification and transesterification reactions from low-grade, highly-acidic and water-containing oils without soap formation. Highly reactive homogeneous Brønsted acid catalysts are efficient for this process, but they suffer from serious contamination and corrosion problems that require the implementation of good separation and purification steps. More recently, a "green" approach to biodiesel production has stimulated the application of sustainable solid acid catalysts as replacements for such liquid acid catalysts so that the use of harmful substances and generation of toxic wastes are avoided; meanwhile, the ease of catalyst separation after the reactions can be realized. Recent studies have proven the technical feasibility and the environmental and economical benefits of biodiesel production via heterogeneous acid-catalyzed esterification and transesterification. In this perspective, various solid acids including sulfated metal oxides, H-form zeolites, sulfonic ion-exchange resins, sulfonic modified mesostructured silica materials, sulfonated carbon-based catalysts, heteropolyacids and acidic ionic liquids are reviewed as heterogeneous catalysts in esterification and transesterification. Meanwhile, for the purpose of facilitating mass-transport of solid acid-catalyzed biodiesel production processes and improving the catalytic stability of the solid acid catalysts in esterification and transesterification reactions, novel and robust organic-inorganic hybrid acid catalysts with unique advantages including strong Brønsted as well as Lewis acid properties, well-defined mesostructure and enhanced surface hydrophobicity are successfully designed, which have been highlighted in this review. This journal is © the Partner Organisations 2014.
Liu J.,Northeast Normal University
PloS one | Year: 2012
Plants and herbivores can evolve beneficial interactions. Growth factors found in animal saliva are probably key factors underlying plant compensatory responses to herbivory. However, there is still a lack of knowledge about how animal saliva interacts with herbivory intensities and how saliva can mobilize photosynthate reserves in damaged plants. The study examined compensatory responses to herbivory and sheep saliva addition for the grass species Leymus chinensis in three experiments over three years. The first two experiments were conducted in a factorial design with clipping (four levels in 2006 and five in 2007) and two saliva treatment levels. The third experiment examined the mobilization and allocation of stored carbohydrates following clipping and saliva addition treatments. Animal saliva significantly increased tiller number, number of buds, and biomass, however, there was no effect on height. Furthermore, saliva effects were dependent on herbivory intensities, associated with meristem distribution within perennial grass. Animal saliva was found to accelerate hydrolyzation of fructans and accumulation of glucose and fructose. The results demonstrated a link between saliva and the mobilization of carbohydrates following herbivory, which is an important advance in our understanding of the evolution of plant responses to herbivory. Herbivory intensity dependence of the effects of saliva stresses the significance of optimal grazing management.
Du D.-Y.,Northeast Normal University |
Qin J.-S.,Northeast Normal University |
Li S.-L.,Nanjing Normal University |
Su Z.-M.,Northeast Normal University |
And 2 more authors.
Chemical Society Reviews | Year: 2014
Polyoxometalate (POM)-based metal-organic framework (MOF) materials contain POM units and generally generate MOF materials with open networks. POM-based MOF materials, which utilize the advantages of both POMs and MOFs, have received increasing attention, and much effort has been devoted to their preparation and relevant applications over the past few decades. They have good prospects in catalysis owing to the electronic and physical properties of POMs that are tunable by varying constituent elements. In this review, we present recent developments in porous POM-based MOF materials, including their classification, synthesis strategies, and applications, especially in the field of catalysis. © 2014 The Royal Society of Chemistry.
Ni W.,Northeast Normal University
Journal of medicinal food | Year: 2010
A neutral polysaccharide fraction (WGPN) prepared from Panax ginseng C.A. Meyer by hot water extraction and DEAE-cellulose chromatography was tested for its anticancer activity alone and in combination with 5-fluorouracil (5-FU) in Sarcoma-180 (S180) tumor-bearing mice by intragastric administration. WGPN alone inhibited S180 tumor growth in a bell-shaped dose-response curve, and the combination with 5-FU showed a synergistic effect. Studies of various immunological activities in S180-bearing mice revealed that WGPN stimulated the proliferation of lymphocytes, increased natural killer cell cytotoxicity, enhanced the phagocytosis and nitric oxide production by macrophages, and increased the level of tumor necrosis factor-alpha in serum. In combination with 5-FU, WGPN mitigated damage to the immune system caused by 5-FU in S180-bearing mice. These results suggest that WGPN might be a potential adjuvant for chemotherapeutic drugs.
Bo X.,Northeast Normal University |
Guo L.,Northeast Normal University
Physical Chemistry Chemical Physics | Year: 2013
Ordered mesoporous boron-doped carbons (BOMCs) were prepared by co-impregnation and carbonization of sucrose and 4-hydroxyphenylboronic acid into SBA-15 silica template. Nitrogen sorption, small angle X-ray diffraction (XRD), and transmission electron microscopy (TEM) reveals that BOMCs possess highly ordered mesoporous structure, uniform pore size distribution, and high surface area. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that B atoms can be successfully doped into the framework of OMCs. Due to the desirable characteristics of BOMCs, BOMCs are highly active, cheap, and selective metal-free electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solution. Although B content is a key factor in determining ORR activity, the ORR activity of BOMCs is also dependent on the surface area. The high surface area of BOMCs facilitates the exposure of the active sites for ORR. BOMCs may be further exploited as potentially efficient and inexpensive metal-free ORR catalysts with good long-term stability in alkaline solution. © 2013 the Owner Societies.
Pan L.,Northeast Normal University |
Bi X.,Northeast Normal University |
Liu Q.,Northeast Normal University
Chemical Society Reviews | Year: 2013
Ketene dithioacetals are versatile intermediates in organic synthesis. Extensive research, since the last decade, has given rise to new prospects in their chemistry. The objective of this review is twofold: first, to highlight the new prospects in the chemistry of functionalized ketene dithioacetals, and second, to provide an intrinsic link between ketene dithioacetal groups and a variety of other functional groups, which has brought out many new facts that will assist in future designs. © 2013 The Royal Society of Chemistry.
Fang G.,Northeast Normal University |
Bi X.,Northeast Normal University |
Bi X.,Nankai University
Chemical Society Reviews | Year: 2015
Silver is a less expensive noble metal. Superior alkynophilicity due to π-coordination with the carbon-carbon triple bond makes silver salts ideal catalysts for alkyne-based organic reactions. This review highlights the progress in alkyne chemistry via silver catalysis primarily over the past five years (ca. 2010-2014). The discussion is developed in terms of the bond type formed with the acetylenic carbon (i.e., C-C, C-N, C-O, C-Halo, C-P and C-B). Compared with other coinage metals such as Au and Cu, silver catalysis is frequently observed to be unique. This critical review clearly indicates that silver catalysis provides a significant impetus to the rapid evolution of alkyne-based organic reactions, such as alkynylation, hydrofunctionalization, cycloaddition, cycloisomerization, and cascade reactions. © The Royal Society of Chemistry.
Wang N.,Northeast Normal University
BMC plant biology | Year: 2010
BACKGROUND: It is widely recognized that interspecific hybridization may induce "genome shock", and lead to genetic and epigenetic instabilities in the resultant hybrids and/or backcrossed introgressants. A prominent component involved in the genome shock is reactivation of cryptic transposable elements (TEs) in the hybrid genome, which is often associated with alteration in the elements' epigenetic modifications like cytosine DNA methylation. We have previously reported that introgressants derived from hybridization between Oryza sativa (rice) and Zizania latifolia manifested substantial methylation re-patterning and rampant mobilization of two TEs, a copia retrotransposon Tos17 and a MITE mPing. It was not known however whether other types of TEs had also been transpositionally reactivated in these introgressants, their relevance to alteration in cytosine methylation, and their impact on expression of adjacent cellular genes. RESULTS: We document in this study that the Dart TE family was transpositionally reactivated followed by stabilization in all three studied introgressants (RZ1, RZ2 and RZ35) derived from introgressive hybridization between rice (cv. Matsumae) and Z. latifolia, while the TEs remained quiescent in the recipient rice genome. Transposon-display (TD) and sequencing verified the element's mobility and mapped the excisions and re-insertions to the rice chromosomes. Methylation-sensitive Southern blotting showed that the Dart TEs were heavily methylated along their entire length, and moderate alteration in cytosine methylation patterns occurred in the introgressants relative to their rice parental line. Real-time qRT-PCR quantification on the relative transcript abundance of six single-copy genes flanking the newly excised or inserted Dart-related TE copies indicated that whereas marked difference in the expression of all four genes in both tissues (leaf and root) were detected between the introgressants and their rice parental line under both normal and various stress conditions, the difference showed little association with the presence or absence of the newly mobilized Dart-related TEs. CONCLUSION: Introgressive hybridization has induced transpositional reactivation of the otherwise immobile Dart-related TEs in the parental rice line (cv. Matsumae), which was accompanied with a moderate alteration in the element's cytosine methylation. Significant difference in expression of the Dart-adjacent genes occurred between the introgressants and their rice parental line under both normal and various abiotic stress conditions, but the alteration in gene expression was not coupled with the TEs.