Identification of a Novel Universal Potential Epitope on the Cytoplasmic Tail of H7N9 Virus Hemagglutinin

<正>Dear Editor,H7 N9 is a recently identified subtype of influenza A virus that caused a major outbreak in humans in China in 2013.According to the latest data provided by the Chinese Center for Disease Control and Prevention(http://www.moh.gov.cn/zwgk/yqbb3/ejlist.shtml, updated on October 31, 2018),the mortality rate of H7 N9 infections in China amounts to     

A subset of chemosensory genes differs between two populations of a specialized leaf beetle after host plant shift

Due to its fundamental role in shaping host selection behavior, we have analyzed the chemosensory repertoire of Chrysomela lapponica. This specialized leaf beetle evolved distinct populations which shifted from the ancestral host plant, willow (Salix sp., Salicaceae), to birch (Betula rotundifolia, Betulaceae). We identified 114 chemosensory candidate genes in adult C. lapponica: 41 olfactory receptors (ORs), eight gustatory receptors, 17 ionotropic receptors, four sensory neuron membrane proteins, 32 odorant binding proteins (OBPs), and 12 chemosensory proteins (CSP) by RNA‐seq. Differential expression analyses in the antennae revealed significant upregulation of one minus‐C OBP (ClapOBP27) and one CSP (ClapCSP12) in the willow feeders. In contrast, one OR (ClapOR17), four minus‐C OBPs (ClapOBP02, 07, 13, 20), and one plus‐C OBP (ClapOBP32) were significantly upregulated in birch feeders. The differential expression pattern in the legs was more complex. To narrow down putative ligands acting as cues for host discrimination, the relative abundance and diversity of volatiles of the two host plant species were analyzed. In addition to salicylaldehyde (willow‐specific), both plant species differed mainly in their emission rate of terpenoids such as (E,E)‐α‐farnesene (high in willow) or 4,8‐dimethylnona‐1,3,7‐triene (high in birch). Qualitatively, the volatiles were similar between willow and birch leaves constituting an “olfactory bridge” for the beetles. Subsequent structural modeling of the three most differentially expressed OBPs and docking studies using 22 host volatiles indicated that ligands bind with varying affinity. We suggest that the evolution of particularly minus‐C OBPs and ORs in C. lapponica facilitated its host plant shift via chemosensation of the phytochemicals from birch as novel host plant.     

Association between variants of EXT2 and type 2 diabetes: a replication and meta-analysis

Recent publications have found an association between variants of exostosin 2 (EXT2) gene and the risk of type 2 diabetes in some population but not in others. In an attempt to address these inconsistencies, we investigated EXT2 variants in two independent cohorts, and conducted a literature-based meta-analysis. Through regression model, we assessed the relationship between the EXT2 single nucleotide polymorphisms (SNPs) (rs3740878, rs11037909 and rs1113132) and the risk of type 2 diabetes in Han Chinese population, including a total of 2,533 cases and 2,643 controls. We combined our data with that from previously published studies and performed a meta-analysis to evaluate the effect size of the gene. Consistent with some studies, we found marginal association for the rs3740878 (OR = 1.07, 95 % CI = 0.99, 1.16, p = 0.09), rs11037909 (OR = 1.07, 95 % CI = 0.99, 1.16, p = 0.08), and rs1113132 (OR = 1.08, 95 % CI = 1.00, 1.17, p = 0.06) in our 2 cohorts. Meta-analysis, comprising 9,224 type 2 diabetes and 10,484 controls, revealed that three SNPs (rs3740878, rs11037909 and rs1113132) in EXT2 were significantly associated with type 2 diabetes (ORs range from 1.06 to 1.07, p = 0.038, p = 0.008 and p = 0.005, respectively). Variation in the EXT2 locus appears to be associated with a small increase in the risk of type 2 diabetes. However, well-designed prospective studies with larger sample size and more ethnic groups are needed to further validate the results.     

Effects of cytokinin on photosynthetic gas exchange, chlorophyll fluorescence parameters, antioxidative system and carbohydrate accumulation in cucumber (Cucumis sativus L.) under low light

The effects of 6-benzylaminopurine (6-BA) on plant growth, net photosynthetic rate, relative chlorophyll content, soluble protein, carbohydrates contents and antioxidant systems of cucumber (Cucumis sativus L.) under low-light environment were investigated using two different cucumber cultivars. The results showed that the weak light resulted in the remarkable decrease in plant net photosynthetic rate, relative chlorophyll content, soluble protein and carbohydrates contents, but promoted the superoxide dismutase and guaiacol peroxidase activities. However, application of 6-BA alleviated the reduction of the correlative parameters and mediated the changes of antioxidant systems. The potential mechanisms may involve the following aspects: 6-BA clearly enhanced the plants’ tolerance to low light by increasing chlorophyll content, reducing the production of superoxide radical (O ₂ ^·? ), and enhancing the quenching of hydrogen peroxide (H₂O₂), consequently alleviating the injury of photosynthetic system, and further increasing the efficiency of CO₂ assimilation, producing more carbohydrates which can meet the growth need of cucumber. Meanwhile, the present study indicated that cucumber of Europe mini type (Chunqiuwang) was more tolerant to low light than HuaNan type (Huza No.3).     

Gene Expression of Neuropilin-1 and Its Receptors,VEGF/Semaphorin 3a,in Normal and Cancer Cells

Extracellular domains of the transmembrane glycoprotein, neuropilin-1 (Np1), specifically bind an array of factors and co-receptors including class-3 semaphorins (Sema3a), vascular endothelial growth factor (VEGF), hepatocyte growth factor, platelet-derived growth factor BB, transforming growth factor-β 1 (TGF-β1), and fibroblast growth factor2 (FGF2). Np1 may have a role in immune response, tumor cell growth, and angiogenesis, but its relative expression in comparison to its co-primary receptors, VEGF and Sema3a, is not known. In this study we determined the mRNA expression of Np1 and its co-receptors, VEGF and Sema3a, and the ratio of VEGF/Sema3a in different human and rodent cell lines. Expression of Np1, VEGF and Sema3a is very low in cells derived from normal tissues, but these proteins are highly expressed in tumor-derived cells. Furthermore, the ratio of VEGF/Sema3a is highly variable in different tumor cells. The elevated mRNA expression of Np1 and its putative receptors in tumor cells suggests a role for these proteins in tumor cell migration and angiogenesis. As different tumor cells exhibit varying VEGF/Sema3a ratios, it appears that cancer cells show differential response to angiogenic factors. These results bring to light the individual variation among the cancer-related genes, Np1, VEGF, and Sema3a, and provide an important impetus for the possible personalized therapeutic approaches for cancer patients.     

ABCG2: A potential marker of stem cells and novel target in stem cell and cancer therapy

ABCG2 is a member of the ATP binding cassette (ABC) transporters, which can pump a wide variety of endogenous and exogenous compounds out of cells. Widely expressed in stem cells, ABCG2 is also found to confer the side population phenotype and is recognized as a universal marker of stem cells. Although the precise physiological role of ABCG2 in stem cells is still unclear, existing data strongly suggest that ABCG2 plays an important role in promoting stem cell proliferation and the maintenance of the stem cell phenotype. In addition, ABCG2 is also found to be expressed in a number of cancer cells and appears to be a marker of cancer stem cells. Moreover, ABCG2 expression in tumors may contribute to their formation and progression. Thus, ABCG2 has potential applications in stem cell and tumor therapy.     

Reaction of Mo(CO)4(NCCH3)2 and 7-aza-2-Tosylnorbornadiene

Reaction of Mo(CO)₄(NCCH₃)₂ and 7-aza-2-tosylnorbornadiene (7-azaNBD) yielded five air-stable Mo complexes. One is Mo(CO)₄(η⁴-7-azaNBD), in which the molybdenum atom is chelated by the two π-bonds of 7-azaNBD. The other four are isomers of Mo(CO)₂(η²-7-azaNBD)₂, in which the molybdenum atoms are chelated by the nitrogen atom and one of the two double bonds of 7-azaNBD. In one pair of the isomers, the metal binds to C(2)C(3) of both 7-azaNBD ligands; whereas in the other pair of isomers the metal binds to C(2)C(3) of one 7-azaNBD ligand and C(5)C(6) of another ligand. All structures were fully characterized by NMR spectra. A single crystal of compound 4 was analyzed by X-ray diffraction analysis, which was found to be monoclinic with a = 8.4199, b = 23.984, c = 16.395 Å, and β = 99.99°.     

Studies on the interaction mechanism between hexakis(imidazole) manganese(II) terephthalate and DNA and preparation of DNA electrochemical sensor

The interaction between hexakis(imidazole) manganese(II) terephthalate ([Mn(Im)(6)](teph).4H(2)O) and salmon sperm DNA in 0.2M pH 2.30 Britton-Robinson buffer solution was studied by fluorescence spectroscopy and cyclic voltammetry. Increasing fluorescence was observed for [Mn(Im)(6)](2+) with DNA addition, while quenching fluorescence phenomenon appeared for EB-DNA system when [Mn(Im)(6)](2+) was added. There were a couple quasi-reversible redox peaks of [Mn(Im)(6)](2+) from the cyclic voltammogram on the glassy carbon electrode. The peak current of [Mn(Im)(6)](2+) decreased with positive shift of the formal potential in the presence of DNA compared with that in the absence of DNA. All the experimental results indicate that [Mn(Im)(6)](2+) can bind to DNA mainly by intercalative binding mode. The binding ratio of the DNA-[Mn(Im)(6)](2+) association complex is calculated to be 1:1 and the binding constant is 4.44x10(3) M(-1). By using [Mn(Im)(6)](teph).4H(2)O as the electrochemical hybridization indicator, the DNA electrochemical sensor was prepared by covalent interaction and the selectivity of ssDNA modified electrode were described. The results demonstrate the use of electrochemical DNA biosensor in the determination of complementary ssDNA.     

Methyl lucidenate F isolated from the ethanol-soluble-acidic components of <Emphasis Type="Italic">Ganoderma lucidum</Emphasis> is a novel tyrosinase inhibitor

Tyrosinase is a key enzyme in the biosynthesis of melanin, and the use of inhibitors against tyrosinase can prevent hyperpigmentation by inhibiting enzymatic oxidation. However, the current use of tyrosine inhibitors is limited by their low activities and high toxicities. The aim of the present research was to develop novel whitening agents, or tyrosinase-targeted medicine, from a submerged culture of the fungus Ganoderma lucidum. Methyl lucidenate F was isolated from the ethanol-soluble-acidic components (ESACs) of G. lucidum, with the structure of ESACs elucidated via UV, LC-MS, and ¹³C-NMR spectral analysis. The tyrosinase inhibitory activity was measured using catechol as a substrate. Methyl lucidenate F displayed uncompetitive inhibition of the potato tyrosinase activity, for which Lineweaver-Burk plots revealed a maximum reaction rate (V _max) of 0.4367/min, Michaelis constant (K _m) of 6.765 mM and uncompetitive inhibition constant (K _i) of 19.22 μM. Meanwhile, methyl lucidenate F (tetra cyclic triterpenoid) exhibited high tyrosinase inhibitory activity, with an IC₅₀ of 32.23 μM. These results suggest that methyl lucidenate F may serve as a potential candidate for skin-whitening agents.     

Molecular phylogenetic relationships of China Seas groupers based on cytochrome <Emphasis Type="Italic">b</Emphasis> gene fragment sequences

The classification and evolutionary relationships are important issues in the study of the groupers. Cytochrome b gene fragment of twenty-eight grouper species within six genera of subfamily Epinephelinae was amplified using PCR techniques and the sequences were analyzed to derive the phylogenetic relationships of the groupers from the China Seas. Genetic information indexes, including Kimura-2 parameter genetic distance and T _S/T _V ratios, were generated by using a variety of biology softwares. With Niphon spinosus, Pagrus major and Pagrus auriga as the designated outgroups, phylogenetic trees, which invoke additional homologous sequences of other Epinephelus fishes from GenBank, were constructed based on the neighbor-joining (NJ), maximum-parsimony (MP), maximum-likelihood (ML) and minimum-evolution (ME) methods. Several conclusions were drawn from the DNA sequences analysis: (1) genus Plectropomus, which was early diverged, is the most primitive group in the subfamily Epinephelinae; (2) genus Variola is more closely related to genus Cephalopolis than the other four genera; (3) genus Cephalopolis is a monophyletic group and more primitive than genus Epinephelus; (4) Promicrops lanceolatus and Cromileptes altivelis should be included in genus Epinephelus; (5) there exist two sister groups in genus Epinephelus.