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排序方式: 共有361条查询结果,搜索用时 31 毫秒
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Summary A method has been developed for rapid mondtoring of lipid production in the intact yeast cells ofRhodotorula
gracilis using1H NMR spectroscopy. 相似文献
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Glycerol production by immobilised cells of Pichia farinosa 总被引:2,自引:0,他引:2
Summary Cells ofPichia
farinosa were immobilised in calcium alginate and K-Carrageenan and their ability to produce glycerol from glucose under aerobic conditions with acidic as well as alkaline pH was investigated. An average glycerol production rate of 0.07 g/l.h was obtained with immobilised cells (IMC) in shake flasks. Continuous glycerol production in a fluidised bed reactor (FBR) under steady state operation gave a glycerol concentration of 13.5 g/l in the product stream. 相似文献
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Extracelluar lipase activity was detected in a culture of Pseudomonas strain Ptm+ growing on hexachlorocyclohexane. Lipase activity was associated with growth of the bacterium and reached a peak at early idiophase (22 h). Following the lipase activity, bioemulsifier was produced, with maximum activity at mid-idiophase (32 h). The extracellular lipase is probably involved in the extracellular synthesis of the bioemulsifier in the culture broth. 相似文献
5.
Summary
Pseudomonas multivorans strain An 1 used aniline but not chloroanilines as the sole source of carbon and energy for growth. The aniline-adapted cells, however, were able to oxygenate chloroanilines. Relative oxygenation rates for aniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline, and 3,4-dichloroaniline were 100, 46, 66, 20, and 3%, respectively.The first intermediates in the metabolism of chloroanilines were chlorocatechols. 3-Chlorocatechol accumulated during growth of the organism in the presence of 2-chloroaniline, whereas 4-chlorocatechol was an intermediate metabolite of 3-chloroaniline and 4-chloroaniline.Chloroanilines were able to induce synthesis of the aniline oxygenating enzyme system of Pseudomonas multivorans strain An 1. In continuous culture experiments, induction of this enzyme system appeared to depend on cell density, concentration, toxicity, and pK-values of aniline or chloroanilines.Studies with 14C-labelled 3-chloroaniline and 4-chloroaniline showed that the turnover of chloroanilines did not cease with the formation of chlorocatechols, because radioactivity was detected in the CO2 released and in bacterial cell components. The results suggest that the turnover of chloroanilines is due to metabolism rather than to cometabolism. 相似文献
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Acetohydroxyacid synthase (AHAS) is an enzyme involved in the biosynthesis of the branched chain amino acids viz, valine, leucine and isoleucine. The activity of this enzyme is regulated through feedback inhibition by the end products of the pathway. Here we report the backbone and side-chain assignments of ilvN, the 22 kDa dimeric regulatory subunit of E. coli AHAS isoenzyme I, in the valine bound form. Detailed analysis of the structure of ilvN and its interactions with the catalytic subunit of E. coli AHAS I will help in understanding the mechanism of activation and regulation of the branched chain amino acid biosynthesis. 相似文献
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Siddharthan Surveswaran Sharad S. Kambale Mansa Srivastav Sachin A. Punekar Shrirang R. Yadav K. Praveen Karanth 《植物分类学报:英文版》2021,59(1):93-112
The Indian subcontinent has experienced a major shift in climatic regime from a wet tropical regime to increased seasonal rainfall, since the late Miocene. This shift has been attributed to the intensification of monsoons, which led to opening up of dry habitats in humid forests and formation of deciduous forests. We explored the role of this climatic shift in the origin and diversification of dry‐adapted plant genera Ceropegia and Brachystelma (Ceropegiae, Asclepiadoideae, Apocynaceae). We sampled Ceropegia and Brachystelma from across India and used five markers (two nuclear and three plastid regions) to reconstruct a global phylogeny of this group. Indian members of the tribe Ceropegiae were derived from Africa through at least four independent dispersal events. All dispersal events occurred in late Miocene after establishment of a monsoon climate. One of these early dispersing lineages underwent rapid radiation in peninsular India, giving rise to around 50 species. Thus, both dispersal and diversification events coincided with the intensification of monsoons and concomitant aridification. The role of environment in the evolution of floral characteristics and root type in the Indian radiation is also discussed. This is one of the first reports on a dry‐adapted endemic radiation of plants in India. 相似文献
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P. Suresh Jayasekara Khai Phan Dilip K. Tosh T. Santhosh Kumar Steven M. Moss Guofeng Zhang Joseph J. Barchi Jr. Zhan-Guo Gao Kenneth A. Jacobson 《Purinergic signalling》2013,9(2):183-198
Gold nanoparticles (AuNPs) allow the tuning of pharmacokinetic and pharmacodynamic properties by active or passive targeting of drugs for cancer and other diseases. We have functionalized gold nanoparticles by tethering specific ligands, agonists and antagonists, of adenosine receptors (ARs) to the gold surface as models for cell surface interactions with G protein-coupled receptors (GPCRs). The AuNP conjugates with chain-extended AR ligands alone (PEGylated nucleosides and nonnucleosides, anchored to the Au via thioctic acid) were found to be insoluble in water due to hydrophobic entities in the ligand. Therefore, we added a second, biologically inactive pendant moiety to increase the water solubility, consisting of a PEGylated chain terminating in a carboxylic or phosphate group. The purity and stability of the immobilized biologically active ligand were examined by ultrafiltration and HPLC. Pharmacological receptor binding studies on these GPCR ligand-derivatized AuNPs (2–5 nm in diameter), performed using membranes of mammalian cells stably expressing human A1, A2A, and A3ARs, showed that the desired selectivity was retained with K i values (nanomolar) of A3AR agonist 21b and A2AAR antagonists 24 and 26a of 14 (A3), 34 (A2A), and 69 (A2A), respectively. The corresponding monomers displayed K i values of 37, 61, and 1,420 nM, respectively. In conclusion, we have synthesized stable, water-soluble AuNP derivatives of tethered A3 and A2AAR ligands that retain the biological properties of their monomeric ligands and are intended for therapeutic and imaging applications. This is the first prototypical application to gold carriers of small molecule (nonpeptide) GPCR ligands, which are under investigation for treatment of cancer and inflammatory diseases. 相似文献
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