This article reports systematic zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd isotopic data for the Early Cretaceous Jialou granitoids along the southernmost margin of the North China Craton (NCC), adjacent t...
详细信息
This article reports systematic zircon U-Pb dating, whole-rock geochemistry, and Sr-Nd isotopic data for the Early Cretaceous Jialou granitoids along the southernmost margin of the North China Craton (NCC), adjacent to the Tongbai Orogen. These results will provide significant constrains on the crustal evolution of the southern margin of the NCC. Zircon U-Pb analyses, using laser ablation-multicollector-inductively coupled plasma-mass spectrometry, indicate that the Jialou granitoids were emplaced at similar to 130Ma. The granitoids have high SiO2, K2O, Al2O3, Sr, and Ba contents, high Sr/Y and (La/Yb)N ratios, and low concentrations of MgO, Y, and heavy rare earth elements, indicating a low-Mg adakitic affinity. They have relatively high initial Sr-87/Sr-86 ratios (0.707464-0.708190) and negative epsilon Nd(t) values (-11.8 to -15.2), similar to those of the Palaeoproterozoic lower crust in the NCC. These geochemical and isotopic features indicate that the Jialou low-Mg adakitic rocks were derived by partial melting of mafic Palaeoproterozoic lower crust of the NCC at >50km depth, leaving behind a garnet amphibolite residue. The petrogenesis of the Jialou low-Mg adakitic rocks, plus the petrogenesis of Mesozoic granitoids and lower crustal xenoliths entrained in the Late Jurassic Xinyang volcaniclastic diatreme, suggests that the continental crust along the southern margin of the NCC was thickened during the Middle Jurassic to Early Cretaceous, but thinned after 130Ma. We propose that crustal thickening was caused by a late Middle Jurassic to Early Cretaceous intra-continental orogeny, rather than continent-continent collision between the NCC and the Yangtze Craton. We also suggest that crustal thinning and Early Cretaceous magmatism were related to subduction of the palaeo-Pacific plate, rather than post-orogenic collapse of the Qinling-Tongbai-Dabie Orogen.
Two coastal Synechococcus stains PCC 7002 and CC9311 and one oceanic strain WH8102 were cultured with 41000 nM Fe in Aquil medium. Compared with those under iron-replete conditions, their growth rates were significant...
详细信息
Two coastal Synechococcus stains PCC 7002 and CC9311 and one oceanic strain WH8102 were cultured with 41000 nM Fe in Aquil medium. Compared with those under iron-replete conditions, their growth rates were significantly decreased by 59% for WH8102 at 15 nM Fe, by 37% for CC9311 at 15 nM Fe and by 57% for PCC 7002 at 4 nM Fe. Among these three strains, PCC 7002 was the most tolerant to iron limitation while WH8102 was the most sensitive to iron limitation. For each strain under the same iron concentration, the growth rates calculated from the minimal fluorescence yield and cell concentration showed no significant difference. The linear correlation was established between the minimal fluorescence yield and cell concentration although the minimal fluorescence yield per cell varied depending on the strains and iron levels. Under iron-replete conditions, the minimal fluorescence yield per cell was 100-fold higher for the phycoerythrin-lacking strain PCC 7002 than two phycoerythrin-containing strains WH8102 and CC9311. Under iron-deplete conditions, it was increased respectively by 128% and 7% for WH8102 and CC9311 but was decreased by 30% for PCC 7002. Furthermore, the minimal fluorescence yield per cell for PCC 7002 and CC9311 showed little difference throughout the light and dark diel cycle. However, it was significantly higher for WH8102 in the daytime than in the dark.
Introduction: Influenza viral ribonucleoprotein complexes (vRNPs) play a key role in viral transcription and replication;hence, the recent development of novel anti-influenza drugs targeting vRNPs has garnered widespr...
详细信息
Introduction: Influenza viral ribonucleoprotein complexes (vRNPs) play a key role in viral transcription and replication;hence, the recent development of novel anti-influenza drugs targeting vRNPs has garnered widespread *** covered: We discuss the function of the constituents of vRNPs and summarize those vRNPs-targeted synthetic drugs that are in preclinical and early clinical *** opinion: vRNPs contain high-value drug targets;such targets include the subunits PA, PB1, PB2, and NP. Developing a new generation of antiviral therapies with strategies that utilize existing drugs, natural compounds originated from new resources and novel drug combinations may open up new therapeutic approaches to influenza.
The gp41 disulfide loop region switches from a soluble state to a membrane-bound state during the human immunodeficiency virus type 1 (HIV-1) envelope-mediated membrane fusion process. The loop possesses a hydrophobic...
详细信息
The gp41 disulfide loop region switches from a soluble state to a membrane-bound state during the human immunodeficiency virus type 1 (HIV-1) envelope-mediated membrane fusion process. The loop possesses a hydrophobic core at the center of the region with an unusual basic residue (Lys-601). Furthermore, two loop core mutations, K601A and L602A, are found to inhibit HIV-1 infectivity while keeping wild type-like levels of the envelope, implying that they exert an inhibitory effect on gp41 during the membrane fusion event. Here, we investigated the mode of action of these mutations on the loop region. We show that the K601A mutation, but not the L602A mutation, abolished the binding of a loop-specific monoclonal antibody to a loop domain peptide. Additionally, the K601A, but not the L602A, impaired disulfide bond formation in the peptides. This was correlated with changes in the circular dichroism spectrum imposed by the K601A mutation. In the membrane, however, the L602A, but not the K601A, reduced the lipid mixing ability of the loop peptides, which was correlated with decreased -helical content of the L602A mutant. The results suggest that the Lys-601 residue provides a moderate hydrophobicity level within the gp41 loop core that contributes to the proper structure and function of the loop inside and outside the membrane. Because basic residues are found between the loop Cys residues of several lentiviral fusion proteins, the findings may contribute to understanding the fusion mechanism of other viruses as well.
Ethnopharmacological relevance: Holotrichia diomphalia larvae are one classical folk medicinal material in East Asia which has clinically been used to promote blood circulation and dispel blood stasis for several hund...
详细信息
Ethnopharmacological relevance: Holotrichia diomphalia larvae are one classical folk medicinal material in East Asia which has clinically been used to promote blood circulation and dispel blood stasis for several hundred years. Aim of the study: The anticoagulant activity of crude extract of H. diomphalia larvae (CEHDL) in vitro and in vivo was evaluated to explore its mechanism as antithrombotic medicine. Materials and methods: The effects of CEHDL on plasma recalcification time, platelet aggregation, bleeding time, hydrolysis of fibrinogen and fibrin were measured with normal human plasma, plasmarich platelet, transected mouse tails and bovine fibrinogen;the anti-thrombosis activities of CEHDL in vitro and in vivo were analyzed with clots lysis assay and carrageenan-induced mouse tail thrombosis model. Results: CEHDL was found to contain large numbers of proteins and could inhibit blood coagulation and platelet aggregation in a dose-dependent manner. Furthermore, CEHDL preferentially cleaved alpha- and beta-chains followed by gamma-chains of fibrinogen. Besides, CEHDL could directly degrade fibrin rather than activate plasminogen. It has been noted that fibrinogenolytic activity of CEHDL could be unaffected by metal ions such as Mg2+, Ca2+, Zn2+, Fe2+, Fe3+, Cu2+ and buffers with pH 3-10. Moreover, protease inhibitors like TPSI, aprotinin, leupetin, PMSF, DTT and EDTA only slightly or not inhibited fibrinogenolytic activity of CEHDL However, CEHDL could be completely inactivated at 75 degrees C and 100 degrees C. In addition, CEHDL exhibited anti-thrombosis activities in both blood clot lysis assay and carrageenan-induced thrombosis model. Conclusion: CEHDL possessed potent anticoagulant activity and several fibrin(ogen)olytic agents from H. diomphalia larvae were responsible for its antithrombotic effect as medicine. (c) 2015 Elsevier Ireland Ltd. All rights reserved.
Seasonal influenza epidemics and influenza pandemics caused by influenza A virus(IAV)has resulted in millions of deaths in the *** development of anti-IAV vaccines and therapeutics is urgently needed for prevention an...
详细信息
Seasonal influenza epidemics and influenza pandemics caused by influenza A virus(IAV)has resulted in millions of deaths in the *** development of anti-IAV vaccines and therapeutics is urgently needed for prevention and treatment of IAV infection and for controlling future influenza ***(HA)of IAV plays a critical role in viral binding,fusion and entry,and contains the major neutralizing ***,HA is an attractive target for developing anti-IAV drugs and *** we have reviewed the recent progress in study of conformational changes of HA during viral fusion process and development of HA-based antiviral therapeutics and vaccines.
Dendrobine, a major component of Dendrobium nobile, increasingly draws attention for its wide applications in health care. Here we explore potential effects of dendrobine against influenza A virus and elucidate the un...
详细信息
Dendrobine, a major component of Dendrobium nobile, increasingly draws attention for its wide applications in health care. Here we explore potential effects of dendrobine against influenza A virus and elucidate the underlying mechanism. Our results indicated that dendrobine possessed antiviral activity against influenza A viruses, including A/FM-1/1/47 (H1N1), A/Puerto Rico/8/34 H274Y (H1N1), and A/Aichi/2/68 (H3N2) with IC50 values of 3.39 +/- 0.32, 2.16 +/- 0.91, 5.32 +/- 1.68 mu g/mL, respectively. Mechanism studies revealed that dendrobine inhibited early steps in the viral replication cycle. Notably, dendrobine could bind to the highly conserved region of viral nucleoprotein (NP), subsequently restraining nuclear export of viral NP and its oligomerization. In conclusion, dendrobine shows potential to be developed as a promising agent to treat influenza virus infection. More importantly, the results provide invaluable information for the full application of the Traditional Chinese Medicine named "Shi Hu".
暂无评论