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Masataka Watanabe 《科学通报(英文版)》2005,50(7):679-684
Land and sea are linked closely by large rivers throughrunoff and sediment discharging and biochemical materialtransferring into the sea[1?3]. The processes carried out byenergy exchange have been in a sensitive response toglobal change[4]. To study the mechanism of sediment transport in the river basin as to reflecting hydromor- phological and climatological controls is thus becoming vital for earth scientists, at present and in the near future since any change in fluvial landform is of a gre… 相似文献
946.
Microsomal glutathione S-transferases: selective up-regulation of leukotriene C4 synthase during lipopolysaccharide-induced pyresis 总被引:4,自引:0,他引:4
Schröder O Sjöström M Qiu H Jakobsson PJ Haeggström JZ 《Cellular and molecular life sciences : CMLS》2005,62(1):87-94
Cysteinyl-leukotrienes (cys-LTs) are potent smooth muscle contracting agents, which play key roles in inflammatory and allergic diseases. The committed step in cys-LT biosynthesis is catalyzed by leukotriene C4 synthase (LTC4S) as well as microsomal glutathione S-transferase type 2 (MGST2) and type 3 (MGST3). Here we report that intraperitoneal injections of lipopolysaccharide in rats lead to a strong increase of LTC4S messenger RNA (mRNA) levels after approximately 1 h, particularly in the heart, brain, adrenal glands and liver, without any significant effect on MGST2 and MGST3 mRNA levels. After 6 h, LTC4S mRNA returns to basal levels, concomitant with a 4.9-, 4.0-, 2.9- and 2.3-fold induction of LTC4S protein in brain, heart, liver and adrenal gland, respectively. Hence, challenge with lipopolysaccharide in vivo causes an organ-selective, local priming for leukotriene C4 synthesis. Moreover, these data suggest that LTC4S and cys-LTs may be involved in acute systemic inflammatory responses such as fever and tachycardia.Received 12 August 2004; received after revision 27 October 2004; accepted 1 November 2004 相似文献
947.
MAGIC, an in vivo genetic method for the rapid construction of recombinant DNA molecules 总被引:1,自引:0,他引:1
We describe a highly engineered in vivo cloning method, mating-assisted genetically integrated cloning (MAGIC), that facilitates the rapid construction of recombinant DNA molecules. MAGIC uses bacterial mating, in vivo site-specific endonuclease cleavage and homologous recombination to catalyze the transfer of a DNA fragment between a donor vector in one bacterial strain and a recipient plasmid in a separate bacterial strain. Recombination events are genetically selected and result in placement of the gene of interest under the control of new regulatory elements with high efficiency. MAGIC eliminates the need for restriction enzymes, DNA ligases, preparation of DNA and all in vitro manipulations required for subcloning and allows the rapid construction of multiple constructs with minimal effort. We show that MAGIC can generate constructs for expression in multiple organisms. As this new method requires only the simple mixing of bacterial strains, it represents a substantial advance in high-throughput recombinant DNA production that will save time, effort and expense in functional genomics studies. 相似文献
948.
Second-generation shRNA libraries covering the mouse and human genomes 总被引:23,自引:0,他引:23
949.
The formation of aminoacyl-transfer RNA is a crucial step in ensuring the accuracy of protein synthesis. Despite the central importance of this process in all living organisms, it remains unknown how archaea and some bacteria synthesize Asn-tRNA and Gln-tRNA. These amide aminoacyl-tRNAs can be formed by the direct acylation of tRNA, catalysed by asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase, respectively. A separate, indirect pathway involves the formation of mis-acylated Asp-tRNA(Asn) or Glu-tRNA(Gln), and the subsequent amidation of these amino acids while they are bound to tRNA, which is catalysed by amidotransferases. Here we show that all archaea possess an archaea-specific heterodimeric amidotransferase (encoded by gatD and gatE) for Gln-tRNA formation. However, Asn-tRNA synthesis in archaea is divergent: some archaea use asparaginyl-tRNA synthetase, whereas others use a heterotrimeric amidotransferase (encoded by the gatA, gatB and gatC genes). Because bacteria primarily use transamidation, and the eukaryal cytoplasm uses glutaminyl-tRNA synthetase, it appears that the three domains use different mechanisms for Gln-tRNA synthesis; as such, this is the only known step in protein synthesis where all three domains have diverged. Closer inspection of the two amidotransferases reveals that each of them recruited a metabolic enzyme to aid its function; this provides direct evidence for a relationship between amino-acid metabolism and protein biosynthesis. 相似文献
950.
Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen 总被引:45,自引:0,他引:45
Stover CK Pham XQ Erwin AL Mizoguchi SD Warrener P Hickey MJ Brinkman FS Hufnagle WO Kowalik DJ Lagrou M Garber RL Goltry L Tolentino E Westbrock-Wadman S Yuan Y Brody LL Coulter SN Folger KR Kas A Larbig K Lim R Smith K Spencer D Wong GK Wu Z Paulsen IT Reizer J Saier MH Hancock RE Lory S Olson MV 《Nature》2000,406(6799):959-964
Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances. 相似文献