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排序方式: 共有747条查询结果,搜索用时 15 毫秒
61.
Kunio Iwatsuki 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(8):270-277
A new term, spherophylon, indicates a unit of life higher than the individual level. To define this term, critical notes are given on the meaning of age in terms of life, the interrelationships among the elements of biodiversity, and an analogy of development between the multicellular body of an individual and the spherophylon. Life is compared at various levels; at the level of the cell, the individual as a multicellular organism, and the spherophylon. The biology of the spherophylon is discussed in the context of integrative biology. 相似文献
62.
基于害虫防治,该文提出了一类具有脉冲效应的食饵依赖捕食系统并进行了分析,根据Floquet乘子理论,我们获得了害虫根除周期解全局渐近稳定与系统持续生存条件. 相似文献
63.
64.
C. Illert 《Il Nuovo Cimento D》1990,12(12):1611-1632
Summary Despite centuries of intense effort amongst mathematicians, and a huge literature in this field, there has previously never
been a generally valid mathematical model of ultrathin elastic ?shells? (actually surfaces) of revolution. This survey paper
presents the first theoretical framework capable of unifying, into a single coherent body of knowledge, a diversity of shapes
associated with elastic bows, car bumper-bars, molluscan shells, even flower-buds and pine-cones. It becomes apparent why
conventional analysis enjoys limited success when approximating elastic cones to perturbedcylinders anddiscs. Also the paper provides a theoretical basis for analysing the wrinkling of compressed engineering structures. These successes,
the new unification and the simplicity of relevant theory which maynever in principle be capable of working in this context. 相似文献
65.
66.
Biology‐Oriented Synthesis of a Withanolide‐Inspired Compound Collection Reveals Novel Modulators of Hedgehog Signaling
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Dr. Jakub Švenda Dipl.‐Biochem. Michael Sheremet M. Sc. Lea Kremer Lukáš Maier Dr. Jonathan O. Bauer Prof. Dr. Carsten Strohmann Dr. Slava Ziegler Dr. Kamal Kumar Prof. Dr. Herbert Waldmann 《Angewandte Chemie (International ed. in English)》2015,54(19):5596-5602
Biology‐oriented synthesis employs the structural information encoded in complex natural products to guide the synthesis of compound collections enriched in bioactivity. The trans‐hydrindane dehydro‐δ‐lactone motif defines the characteristic scaffold of the steroid‐like withanolides, a plant‐derived natural product class with a diverse pattern of bioactivity. A withanolide‐inspired compound collection was synthesized by making use of three key intermediates that contain this characteristic framework derivatized with different reactive functional groups. Biological evaluation of the compound collection in cell‐based assays that monitored biological signal‐transduction processes revealed a novel class of Hedgehog signaling inhibitors that target the protein Smoothened. 相似文献
67.
Dr. Michael Georg Hoesl M. Sc. Stefan Oehm Dr. Patrick Durkin Dr. Elise Darmon Dr. Lauri Peil Dr. Hans‐Rudolf Aerni Prof. Dr. Juri Rappsilber Prof. Dr. Jesse Rinehart Prof. Dr. David Leach Prof. Dr. Dieter Söll Prof. Dr. Nediljko Budisa 《Angewandte Chemie (International ed. in English)》2015,54(34):10030-10034
We have changed the amino acid set of the genetic code of Escherichia coli by evolving cultures capable of growing on the synthetic noncanonical amino acid L ‐β‐(thieno[3,2‐b]pyrrolyl)alanine ([3,2]Tpa) as a sole surrogate for the canonical amino acid L ‐tryptophan (Trp). A long‐term cultivation experiment in defined synthetic media resulted in the evolution of cells capable of surviving Trp→[3,2]Tpa substitutions in their proteomes in response to the 20 899 TGG codons of the E. coli W3110 genome. These evolved bacteria with new‐to‐nature amino acid composition showed robust growth in the complete absence of Trp. Our experimental results illustrate an approach for the evolution of synthetic cells with alternative biochemical building blocks. 相似文献
68.
69.
Spontaneous Reconstitution of Functional Transmembrane Proteins During Bioorthogonal Phospholipid Membrane Synthesis
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Christian M. Cole Dr. Roberto J. Brea Young Hun Kim Michael D. Hardy Prof. Jerry Yang Prof. Neal K. Devaraj 《Angewandte Chemie (International ed. in English)》2015,54(43):12738-12742
Transmembrane proteins are critical for signaling, transport, and metabolism, yet their reconstitution in synthetic membranes is often challenging. Non‐enzymatic and chemoselective methods to generate phospholipid membranes in situ would be powerful tools for the incorporation of membrane proteins. Herein, the spontaneous reconstitution of functional integral membrane proteins during the de novo synthesis of biomimetic phospholipid bilayers is described. The approach takes advantage of bioorthogonal coupling reactions to generate proteoliposomes from micelle‐solubilized proteins. This method was successfully used to reconstitute three different transmembrane proteins into synthetic membranes. This is the first example of the use of non‐enzymatic chemical synthesis of phospholipids to prepare proteoliposomes. 相似文献
70.
Fragment‐Based De Novo Design Reveals a Small‐Molecule Inhibitor of Helicobacter Pylori HtrA
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Thomas P. Schmidt Dr. Manja Böhm Katharina Stutz Daniel Reker Dr. Bernhard Pfeiffer Prof. Dr. Karl‐Heinz Altmann Prof. Dr. Steffen Backert Prof. Dr. Silja Wessler Prof. Dr. Gisbert Schneider 《Angewandte Chemie (International ed. in English)》2015,54(35):10244-10248
Sustained identification of innovative chemical entities is key for the success of chemical biology and drug discovery. We report the fragment‐based, computer‐assisted de novo design of a small molecule inhibiting Helicobacter pylori HtrA protease. Molecular binding of the designed compound to HtrA was confirmed through biophysical methods, supporting its functional activity in vitro. Hit expansion led to the identification of the currently best‐in‐class HtrA inhibitor. The results obtained reinforce the validity of ligand‐based de novo design and binding‐kinetics‐guided optimization for the efficient discovery of pioneering lead structures and prototyping drug‐like chemical probes with tailored bioactivity. 相似文献