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排序方式: 共有2150条查询结果,搜索用时 15 毫秒
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Olivia Sveidahl Johansen Tao Ma Jakob Bondo Hansen Lasse Kruse Markussen Renate Schreiber Laia Reverte-Salisa Hua Dong Dan Ploug Christensen Wenfei Sun Thorsten Gnad Iuliia Karavaeva Thomas Svava Nielsen Sander Kooijman Cheryl Cero Oksana Dmytriyeva Yachen Shen Maria Razzoli Shannon L. O’Brien Zachary Gerhart-Hines 《Cell》2021,184(13):3502-3518.e33
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A double antibody radioimmunoassay technique is described for the measurement of anti-zona antibodies in the peripheral plasma of marmosets actively immunized against intact cow zonae pellucidae. The method has been shown to be a reliable, repeatable indicator of antibody titer, enabling direct comparison of the response obtained between marmosets. This is the first report of a procedure describing the active immunization of a primate against zona antigens, and the first time a radioimmunoassay technique has been used to monitor profiles of anti-cow zona antibody production following active immunization. The method should prove to be a useful tool in the evaluation of zona antigens as agents for immunocontraception. 相似文献
5.
Filippo Genovese Stefania Ferrari Giambattista Guaitoli Monica Caselli M. Paola Costi Glauco Ponterini 《Protein science : a publication of the Protein Society》2010,19(5):1023-1030
An ad hoc bioconjugation/fluorescence resonance energy transfer (FRET) assay has been designed to spectroscopically monitor the quaternary state of human thymidylate synthase dimeric protein. The approach enables the chemoselective engineering of allosteric residues while preserving the native protein functions through reversible masking of residues within the catalytic site, and is therefore suitable for activity/oligomerization dual assay screenings. It is applied to tag the two subunits of human thymidylate synthase at cysteines 43 and 43′ with an excitation energy donor/acceptor pair. The dimer–monomer equilibrium of the enzyme is then characterized through steady‐state fluorescence determination of the intersubunit resonance energy transfer efficiency. 相似文献
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The wolfberry (Lycium barbarumL.) fruit has been used in traditional Chinese medicine and food, but fruits grown in various geographic areas are significantly different in quality and content of functional components. In this study, we tested the internal nutritional ingredients and related environmental factors using forty-two wolfberry fruits collected from seven wolfberry producing regions in China (Yinchuan and Zhongning in Ningxia, Jingyuan in Gansu, Nuomuhong Farm in Qinghai,Hangjinhouqi and Wulateqianqi in Inner Mongolia, and Jinghe in Xinjiang). The nutritional ingredients of the forty-two wolfberry fruits are dependent on the environment. Correlation analysis revealed that the amount of nutrients was highly related to each other. Based on the analysis ofratio of total sugar to betaine (sugar-alkali ratio), we have successfully established quality standards for the wolfberry based on the levels of betaine and sugar. The standards were as follows: high betaine low sugar (sugar-alkali ratio≤15.1), high betaine medium sugar (15<sugar-alkali ratio≤60), medium betaine medium sugar (60<sugar-alkali ratio≤121), medium betaine high sugar (121<sugar-alkali ratio≤165), and low betaine high sugar (sugar-alkali ratio>165). Zhongning of Ningxia is the geo-authentic producing region of the wolfberry, whereby the wolfberries are rich in main pharmacological ingredients Lycium barbarum polysaccharide (LBP) and three trace elements (iron, manganese and selenium) and medium sugar-alkali ratio. In addition, the correlation analysis showed that both the altitude and average temperature difference between day and night had positive effects on the wolfberry flavonoids content but the annual sunshine duration negatively affected the betaine contents of the wolfberry fruit. 相似文献
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Molecular graphics and molecular mechanics techniques have been used to study the mode of ligand binding and mechanism of action of the enzyme phospholipase A2. A substrate-enzyme complex was constructed based on the crystal structure of the apoenzyme. The complex was minimized to relieve initial strain, and the structural and energetic features of the resultant complex analyzed in detail, at the molecular and residue level. The minimized complex was then used as a basis for examining the action of the enzyme on modified substrates, binding of inhibitors to the enzyme, and possible reaction intermediate complexes. The model is compatible with the suggested mechanism of hydrolysis and with experimental data about stereoselectivity, efficiency of hydrolysis of modified substrates, and inhibitor potency. In conclusion, the model can be used as a tool in evaluating new ligands as possible substrates and in the rational design of inhibitors, for the therapeutic treatment of diseases such as rheumatoid arthritis, atherosclerosis, and asthma. 相似文献
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Jan Sielewiesiuk 《Acta Physiologiae Plantarum》2002,24(4):399-406
An explanation of photodamages to PS II at low light intensities is proposed. The explanation is based on the two following
postulates: 1. Intermediate states of the water-oxidizing complex can undergo parasitic reduction to lower degrees of oxidation.
2. Photosynthetic apparatus can minimize the unfavorable effect of such reduction by changes in the number of active reaction
centers of PS II. Some steady-state characteristics were calculated under these assumptions. The results obtained show that
the frequency of P680 excitations at low light intensities becomes as high as that at saturating light provided that the rate
of parasitic reduction is comparable with the rate of the slowest reaction in the cycle of the water- oxidizing complex conversions. 相似文献
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Michael A. Borowitzka 《Journal of applied phycology》1995,7(1):3-15
In the last decade the screening of microalgae, especially the cyanobacteria (blue-green algae), for antibiotics and pharmacologically
active compounds has received ever increasing interest. A large number of antibiotic compounds, many with novel structures,
have been isolated and characterised. Similarly many cyanobacteria have been shown to produce antiviral and antineoplastic
compounds. A range of pharmacological activities have also been observed with extracts of microalgae, however the active principles
are as yet unknown in most cases. Several of the bioactive compounds may find application in human or veterinary medicine
or in agriculture. Others should find application as research tools or as structural models for the development of new drugs.
The microalgae are particularly attractive as natural sources of bioactive molecules since these algae have the potential
to produce these compounds in culture which enables the production of structurally complex molecules which are difficult or
impossible to produce by chemical synthesis. 相似文献