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991.
The minor receptor group of human rhinovirus (HRV) includes HRV23 and HRV25, but the presence of a lysine in the VP1 HI loop is not sufficient for receptor binding 下载免费PDF全文
Vlasak M Roivainen M Reithmayer M Goesler I Laine P Snyers L Hovi T Blaas D 《Journal of virology》2005,79(12):7389-7395
Like all 10 minor receptor group human rhinoviruses (HRVs), HRV23 and HRV25, previously classified as major group viruses, are neutralized by maltose binding protein (MBP)-V33333 (a soluble recombinant concatemer of five copies of repeat 3 of the very-low-density lipoprotein receptor fused to MBP), bind to low-density lipoprotein receptor in virus overlay blots, and replicate in intercellular adhesion molecule 1 (ICAM-1)-negative COS-7 cells. From phylogenetic analysis of capsid protein VP1-coding sequences, they are also known to cluster together with other minor group strains. Therefore, they belong to the minor group; there are now 12 minor group and 87 major group HRV serotypes. Sequence comparison of the VP1 capsid proteins of all HRVs revealed that the lysine in the HI loop, strictly conserved in the 12 minor group HRVs, is also present in 9 major group serotypes that are neutralized by soluble ICAM-1. Despite the presence of this lysine, they are not neutralized by MBP-V33333 and fail to replicate in COS-7 cells and in HeLa cells in the presence of an ICAM-1-blocking antibody. These nine serotypes are therefore "true" major group viruses. 相似文献
992.
993.
Root-derived cytokinins as long-distance signals for NO3--induced stimulation of leaf growth 总被引:9,自引:0,他引:9
Rahayu YS Walch-Liu P Neumann G Römheld V von Wirén N Bangerth F 《Journal of experimental botany》2005,56(414):1143-1152
Leaf growth of many plant species shows rapid changes in response to alterations of the form and the level of N supply. In hydroponically-grown tomato (Lycopersicon esculentum L.), leaf growth was rapidly stimulated by NO(3)(-) application to NH(4)(+) precultured plants, while NH(4)(+) supply or complete N deprivation to NO(3)(-) precultured plants resulted in a rapid inhibition of leaf growth. Just 10 microM NO(3)(-) supply was sufficient to stimulate leaf growth to the same extent as 2 mM. Furthermore, continuous NO(3)(-) supply induced an oscillation of leaf growth rate with a 48 h interval. Since changes in NO(3)(-) levels in the xylem exudate and leaves did not correlate with NO(3)(-)-induced alterations of leaf growth rate, additional signals such as phytohormones may be involved. Levels of a known inhibitor of leaf growth, abscisic acid (ABA), did not consistently correspond to leaf growth rates in wild-type plants. Moreover, leaf growth of the ABA-deficient tomato mutant flacca was inhibited by NH(4)(+) without an increase in ABA concentration and was stimulated by NO(3)(-) despite its excessive ethylene production. These findings suggest that neither ABA nor ethylene are directly involved in the effects of N form on leaf growth. However, under all experimental conditions, stimulation of leaf growth by NO(3)(-) was consistently associated with increased concentration of the physiologically active forms of cytokinins, zeatin and zeatin riboside, in the xylem exudate. This indicates a major role for cytokinins as long-distance signals mediating the shoot response to NO(3)(-) perception in roots. 相似文献
994.
Metagenomic gene discovery: past, present and future 总被引:22,自引:0,他引:22
Cowan D Meyer Q Stafford W Muyanga S Cameron R Wittwer P 《Trends in biotechnology》2005,23(6):321-329
It is now widely accepted that the application of standard microbiological methods for the recovery of microorganisms from the environment has had limited success in providing access to the true extent of microbial biodiversity. It follows that much of the extant microbial genetic diversity (collectively termed the metagenome) remains unexploited, an issue of considerable relevance to a wider understanding of microbial communities and of considerable importance to the biotechnology industry. The recent development of technologies designed to access this wealth of genetic information through environmental nucleic acid extraction has provided a means of avoiding the limitations of culture-dependent genetic exploitation. 相似文献
995.
Oakes ND Thalén P Hultstrand T Jacinto S Camejo G Wallin B Ljung B 《American journal of physiology. Regulatory, integrative and comparative physiology》2005,289(4):R938-R946
Insulin resistance, impaired glucose tolerance, high circulating levels of free fatty acids (FFA), and postprandial hyperlipidemia are associated with the metabolic syndrome, which has been linked to increased risk of cardiovascular disease. We studied the metabolic responses to an oral glucose/triglyceride (TG) (1.7/2.0 g/kg lean body mass) load in three groups of conscious 7-h fasted Zucker rats: lean healthy controls, obese insulin-resistant/dyslipidemic controls, and obese rats treated with the dual peroxisome proliferator-activated receptor alpha/gamma agonist, tesaglitazar, 3 mumol.kg(-1).day(-1) for 4 wk. Untreated obese Zucker rats displayed marked insulin resistance, as well as glucose and lipid intolerance in response to the glucose/TG load. The 2-h postload area under the curve values were greater for glucose (+19%), insulin (+849%), FFA (+53%), and TG (+413%) compared with untreated lean controls. Treatment with tesaglitazar lowered fasting plasma glucose, improved glucose tolerance, substantially reduced fasting and postload insulin levels, and markedly lowered fasting TG and improved lipid tolerance. Fasting FFA were not affected, but postprandial FFA suppression was restored to levels seen in lean controls. Mechanisms of tesaglitazar-induced lowering of plasma TG were studied separately using the Triton WR1339 method. In anesthetized, 5-h fasted, obese Zucker rats, tesaglitazar reduced hepatic TG secretion by 47%, increased plasma TG clearance by 490%, and reduced very low-density lipoprotein (VLDL) apolipoprotein CIII content by 86%, compared with obese controls. In conclusion, the glucose/lipid tolerance test in obese Zucker rats appears to be a useful model of the metabolic syndrome that can be used to evaluate therapeutic effects on impaired postprandial glucose and lipid metabolism. The present work demonstrates that tesaglitazar ameliorates these abnormalities and enhances insulin sensitivity in this animal model. 相似文献
996.
Luca?CastriotaEmail author Maria?Pia?Scarabello Maria?Grazia?Finoia Mauro?Sinopoli Franco?Andaloro 《Environmental Biology of Fishes》2005,72(2):123-133
We collected pearly razorfish, Xyrichtys novacula (Labridae), from a sandy bottom of Capo dOrlando (Tyrrhenian Sea) to study their feeding habits. We caught fish by hand-lines and seine nets and identified, counted and weighed food items in their stomachs. We evaluated the importance of the different prey types by calculating the frequency of occurrence, abundance and mass. We used these values to calculate the index of relative importance (IRI) for each taxonomic category and a modified index (MI) which did not incorporate %N into the formula. Gammarideans were dominant food items in terms of %F but showed a very low MI value; the bivalve Acanthocardia tubercolata was the dominant species in terms of %W and MI value. The prey items were mostly benthic organisms belonging to the assemblage of fine, well-sorted sands showing that X. novacula is a benthic feeder. Despite the large number of prey taxa found, few species accounted for most of the prey consumed, indicating specialist feeding, as confirmed by the low value of the Levins standardised index. We found significant differences in prey distribution among size classes, with the highest prey diversity recorded in 120–140 mm TL size classes. Correspondence analysis showed a trend of increasing predator size classes among prey items, with small prey, such as copepods and amphipods, in the smallest predator size classes and bigger prey in the larger ones. Prey caught by larger predators differed significantly in weight from those taken by smaller specimens. There was a significant positive correlation of fish length with bivalves, decapods and echinoids, and a negative one with copepods, ostracods, caprellids, gammarideans. There were no significant differences between males and females of overlapping sizes. Juveniles are able to exploit only small, vulnerable prey, while adults take few, large prey, thereby avoiding competition with juveniles. 相似文献
997.
The reaction mechanism of the oxidation of 2,6-dichlorophenol (2,6-DCP) by horseradish peroxidase (HRP) and H2O2 has been investigated and the reaction products have been characterized by UV-visible and mass spectrometry. Evidence for the dimerization of 2,6-DCP to 3,3',5,5'-tetrachloro-4,4'-dihydroxybiphenyl and the subsequent fast oxidation of this product to the corresponding 3,3',5,5'-tetrachlorodiphenoquinone have been collected. The reaction rate was found to decrease markedly as soon as the pH was raised, with a clear inflection point at pH congruent with 6.6-6.9; it also resulted independent from H2O2 concentration. Since the pK(a) for 2,6-DCP is 6.80, the reaction rate might be influenced by the protonation state of the substrate. 相似文献
998.
Ali-Salaam P Kashgarian M Davila J Persing J 《Plastic and reconstructive surgery》2002,110(1):261-6; discussion 267-71
Anatomic studies performed on the noses of 15 cadavers examined the alar groove, alar lobule, and lower lateral crus areas both microscopically and on gross appearance to determine what effect these structures have on overall nasal appearance. In contrast to the findings of previous studies, the authors found the alar lobule to be an area in which dermis is interdigitated with muscle throughout and up to the alar rim. The anteroposterior lengths of the lower lateral crura were again seen to vary in length, presence or absence of accessory cartilages, and shape. Neither corrugation of the posterior elongation nor overlap of the accessory cartilages of the lower lateral cartilage had an effect on phenotype; sharp angles formed by the cartilage were blunted by the layer of fibrofatty muscular tissue between the cartilage and the skin. The alar groove, which lies at the junction of the lower lateral crus (medially) and the alar lobule (laterally), is defined not as much by a muscular attachment between the perichondrium of the lower lateral cartilage and the vestibular mucosa as by a bulging in the fatty layer on one side of the groove (within the cheek, lateral nasal wall, and nasal tip) and a relative paucity of fatty tissue on its other side (within the alar lobule). 相似文献
999.
1000.
A susceptibility locus for migraine with aura, on chromosome 4q24 总被引:18,自引:0,他引:18
Wessman M Kallela M Kaunisto MA Marttila P Sobel E Hartiala J Oswell G Leal SM Papp JC Hämäläinen E Broas P Joslyn G Hovatta I Hiekkalinna T Kaprio J Ott J Cantor RM Zwart JA Ilmavirta M Havanka H Färkkilä M Peltonen L Palotie A 《American journal of human genetics》2002,70(3):652-662
Migraine is a complex neurovascular disorder with substantial evidence supporting a genetic contribution. Prior attempts to localize susceptibility loci for common forms of migraine have not produced conclusive evidence of linkage or association. To date, no genomewide screen for migraine has been published. We report results from a genomewide screen of 50 multigenerational, clinically well-defined Finnish families showing intergenerational transmission of migraine with aura (MA). The families were screened using 350 polymorphic microsatellite markers, with an average intermarker distance of 11 cM. Significant evidence of linkage was found between the MA phenotype and marker D4S1647 on 4q24. Using parametric two-point linkage analysis and assuming a dominant mode of inheritance, we found for this marker a maximum LOD score of 4.20 under locus homogeneity (P=.000006) or locus heterogeneity (P=.000011). Multipoint parametric (HLOD = 4.45; P=.0000058) and nonparametric (NPL(all) = 3.43; P=.0007) analyses support linkage in this region. Statistically significant linkage was not observed in any other chromosomal region. 相似文献