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31.
Four new hetisine‐type C20‐diterpenoid alkaloids, named as coreanines A–D ( 1 – 4 ), were isolated from the roots of Aconitum coreanum, together with thirteen known alkaloids ( 5 – 17 ). Their structures were elucidated by extensive spectroscopic methods including IR, HR‐ESI‐MS and NMR techniques. All the isolated compounds were screened for the acetylcholinesterase (AChE) inhibitory effects, and none of them showed considerable inhibitory activity. 相似文献
32.
Shu-Qun Liu Yan Tao Zhao-Hui Meng Yun-Xin Fu Ke-Qin Zhang 《Journal of molecular modeling》2011,17(2):289-300
The native serine protease proteinase K binds two calcium cations. It has been reported that Ca2+ removal decreased the enzyme’s thermal stability and to some extent the substrate affinity, but has discrepant effects on
catalytic activity of the enzyme. Molecular dynamics simulations were performed on the Ca2+-bound and Ca2+-free proteases to investigate the mechanism by which the calciums affect the structural stability, molecular motions, and
catalytic activity of proteinase K. Very similar structural properties were observed between these two forms of proteinase
K during simulations; and several long-lived hydrogen bonds and salt bridges common to both forms of proteinase K were found
to be crucial in maintaining the local conformations around these two Ca2+ sites. Although Ca2+ removal enhanced the overall flexibility of proteinase K, the flexibility in a limited number of segments surrounding the
substrate-binding pockets decreased. The largest differences in the equilibrium structures of the two simulations indicate
that, upon the removal of Ca2+, the large concerted motion originating from the Ca1 site can transmit to the substrate-binding regions but not to the catalytic
triad residues. In conjunction with the large overlap of the essential subspaces between the two simulations, these results
not only provide insight into the dynamics of the underlying molecular mechanism responsible for the unchanged enzymatic activity
as well as the decreased thermal stability and substrate affinity of proteinase K upon Ca2+ removal, but also complement the experimentally determined structural and biochemical data. 相似文献
33.
Li Zhang Shan Lei Hui Xie Qianqian Li Shuo Liu Qiang Liu Weijin Huang Xinyue Xiao Youchun Wang 《中国病毒学》2020,35(2):235-239
正Dear Editor,Marburg virus(MARV) belongs to the Filoviridae family,along with the related Ebola virus(EBOV). Although MARV is less renowned than EBOV, it causes an equally devastating disease, with clinical symptoms similar to EBOV infection and a remarkably high mortality rate. To 相似文献
34.
While host proteins incorporated into virions during viral budding from infected cell are known to play essential roles in multiple process of the life cycle of progeny virus, these characteristics have been largely neglected in studies on rabies virus(RABV). Here, we purified the RABV virions with good purity and integrity, and analyzed their proteome by nano LC–MS/MS, followed by the confirmation with immunoblot and immuno-electronic microscopy. In addition to the 5 viral proteins, 49 cellular proteins were reproducibly identified to be incorporated into matured RABV virions. Function annotation suggested that 24 of them were likely involved in virus replication. Furthermore, cryo-EM was employed to observe the purified RABV virions, generating high-resolution pictures of the bullet-shaped virion structure of RABV. This study has provided new insights into the host proteins composition in RABV virion and shed the light for further investigation on molecular mechanisms of RABV infection, as well as the discovery of new anti-RABV therapeutics. 相似文献
35.
Yun Guo Yuejun He Pan Wu Bangli Wu Yan Lin Minhong He Xu Han Tingting Xia Kaiping Shen Liling Kang Qiyu Tan Wenda Ren Yan Sun Qing Li 《Journal of Plant Ecology》2022,15(2):399
AM 真菌和枯落物互作下两种喀斯特植物种间竞争较种内竞争更能促进植物养分利用
枯落物是植物养分获取和土壤养分转化的关键载体。丛枝菌根(Arbuscular mycorrhizae, AM)对植物养分摄取的影响已被广泛认知。然而,在养分亏缺的喀斯特生境中,不同竞争方式的植物如何通过AM真菌和枯落物利用养分尚不清楚。本研究对两种喀斯特适生植物构树(Broussonetia papyrifera)和云贵鹅耳枥(Carpinus pubescens)进行种内竞争和种 间竞争种植处理,并通过幼套球 囊霉(Glomus etunicatum)接种或不接种处理,以及土壤中添加或不添加两物种叶片混合枯落物处理,测定了植物生物量以及氮、磷、钾浓度等指标,研究植物的生长和养分利用。研究结果表明,AM真菌对两种植物养分摄取影响不同,AM真菌显著提高了种内和种间竞争下构树的养分摄取量,但降低了云贵鹅耳枥的养分摄取量。种间竞争下接种AM真菌,枯落物添加促进了云贵鹅耳枥对氮的摄取,抑制了构树对氮的摄取。接种AM真菌和添加枯落物条件下,种间竞争的构树对氮、磷和钾的摄取量及云贵鹅耳枥对氮的摄取量均高于种内竞争;种间竞争下两物种养分竞争力呈现明显差异,即构树对磷和钾养分竞争力显著提高,对氮则不显著;云贵鹅耳枥仅对钾的养分竞争力显著降低,对氮和磷则无显著影响。这些结果说明,在AM真菌与枯落物相互作用下,两种喀斯特植物种间竞争较种内竞争更能促进植物养分利用。 相似文献
36.
37.
38.
C K?nig Y L Yan J Postlethwait S Wendler J A Campos-Ortega 《Mechanisms of development》1999,86(1-2):17-28
We describe the characterization of the zebrafish homologue of the human gene DLG3. The zebrafish dlg3 gene encodes a membrane-associated guanylate kinase containing a single PDZ domain. This gene was cloned using a gene-trap construct inserted in the gene's first intron. The insertion co-segregates with a viable mutation called humpback (hmp), which leads to formation of ankylotic vertebrae in adult fishes. Insertion and mutation have both been mapped to chromosome 12, in a segment which is syntenic with region p12 to q12 of human chromosome 17. The hmp mutant phenotype, however, appears to be due to two point mutations in the guanylate kinase domain rather than to the transgene insertion itself. The results of this study are discussed in the light of the possible function of the guanylate kinase domain. 相似文献
39.
Wen-Jing Yan Xiaobai Li Su-Jing Wang Guoying Zhao Yong-Jin Liu Yu-Hsin Chen Xiaolan Fu 《PloS one》2014,9(1)
A robust automatic micro-expression recognition system would have broad applications in national safety, police interrogation, and clinical diagnosis. Developing such a system requires high quality databases with sufficient training samples which are currently not available. We reviewed the previously developed micro-expression databases and built an improved one (CASME II), with higher temporal resolution (200 fps) and spatial resolution (about 280×340 pixels on facial area). We elicited participants'' facial expressions in a well-controlled laboratory environment and proper illumination (such as removing light flickering). Among nearly 3000 facial movements, 247 micro-expressions were selected for the database with action units (AUs) and emotions labeled. For baseline evaluation, LBP-TOP and SVM were employed respectively for feature extraction and classifier with the leave-one-subject-out cross-validation method. The best performance is 63.41% for 5-class classification. 相似文献
40.
Satoshi Hirohata Lauren W Wang Masaru Miyagi Lin Yan Michael F Seldin Douglas R Keene John W Crabb Suneel S Apte 《The Journal of biological chemistry》2002,277(14):12182-12189
Punctin (ADAMTSL-1) is a secreted molecule resembling members of the ADAMTS family of proteases. Punctin lacks the pro-metalloprotease and the disintegrin-like domain typical of this family but contains other ADAMTS domains in precise order including four thrombospondin type I repeats. Punctin is the product of a distinct gene on human chromosome 9p21-22 and mouse chromosome 4 that is expressed in adult skeletal muscle. His-tagged punctin expressed in stably transfected High-Five(TM) insect cells was purified to apparent homogeneity by Ni-chromatography of conditioned medium. The NH(2) terminus is not blocked and has the sequence EEDRD and so forth as determined by Edman degradation, demonstrating signal peptidase processing. Recombinant epitope-tagged punctin has a calculated mass of 59,991 Da but exhibits major molecular species of 61970 +/- 6 Da and 62131 +/- 5 Da as measured by liquid chromatography electrospray mass spectrometry. Punctin is a glycoprotein based on carbohydrate staining and liquid chromatography electrospray mass spectrometry glycopeptide analysis. Glycosylation occurs at a single N-linked site as demonstrated by altered electrophoretic migration of punctin expressed in the presence of tunicamycin A. Punctin contains disulfide bonds based on antibody accessibility and electrophoretic migration under reducing versus nonreducing conditions. Rotary shadowing demonstrates that punctin is hatchet-shaped having a globular region attached to a short stem. In transfected COS-1 cells, punctin is deposited in the cell substratum in a punctate fashion and is excluded from focal contacts. Punctin is the first member of a novel family of ADAMTS-like proteins that may have important functions in the extracellular matrix. 相似文献