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排序方式: 共有537条查询结果,搜索用时 15 毫秒
531.
Swartz TE Tseng TS Frederickson MA Paris G Comerci DJ Rajashekara G Kim JG Mudgett MB Splitter GA Ugalde RA Goldbaum FA Briggs WR Bogomolni RA 《Science (New York, N.Y.)》2007,317(5841):1090-1093
Histidine kinases, used for environmental sensing by bacterial two-component systems, are involved in regulation of bacterial gene expression, chemotaxis, phototaxis, and virulence. Flavin-containing domains function as light-sensory modules in plant and algal phototropins and in fungal blue-light receptors. We have discovered that the prokaryotes Brucella melitensis, Brucella abortus, Erythrobacter litoralis, and Pseudomonas syringae contain light-activated histidine kinases that bind a flavin chromophore and undergo photochemistry indicative of cysteinyl-flavin adduct formation. Infection of macrophages by B. abortus was stimulated by light in the wild type but was limited in photochemically inactive and null mutants, indicating that the flavin-containing histidine kinase functions as a photoreceptor regulating B. abortus virulence. 相似文献
532.
TFEB links autophagy to lysosomal biogenesis 总被引:1,自引:0,他引:1
533.
Suppression of ovarian follicle activation in mice by the transcription factor Foxo3a 总被引:1,自引:0,他引:1
Castrillon DH Miao L Kollipara R Horner JW DePinho RA 《Science (New York, N.Y.)》2003,301(5630):215-218
534.
Walther DJ Peter JU Bashammakh S Hörtnagl H Voits M Fink H Bader M 《Science (New York, N.Y.)》2003,299(5603):76
535.
A new synthetic route to cyclic polymers has been developed in which the ends of growing polymer chains remain attached to a metal complex throughout the entire polymerization process. The approach eliminates the need for linear polymeric precursors and high dilution, drawbacks of traditional macrocyclization strategies, and it effectively removes the barrier to producing large quantities of pure cyclic material. Ultimately, the strategy offers facile access to a unique macromolecular scaffold that may be used to meet the increasing demand of new applications for commercial polymers. As a demonstration of its potential utility, cyclic polyethylenes were prepared and found to exhibit a variety of physical properties that were distinguishable from their linear analogs. 相似文献
536.
Effects of microwave cooking conditions on bioactive compounds present in broccoli inflorescences 总被引:2,自引:0,他引:2
López-Berenguer C Carvajal M Moreno DA García-Viguera C 《Journal of agricultural and food chemistry》2007,55(24):10001-10007
Cooking as a domestic processing method has a great impact on food nutrients. Most Brassica (Brassicaceae, Cruciferae) vegetables are mainly consumed after being cooked, and cooking considerably affects their health-promoting compounds (specifically, glucosinolates, phenolic compunds, minerals, and vitamin C studied here). The microwave cooking process presents controversial results in the literature due to the different conditions that are employed (time, power, and added water). Therefore, the aim of this work was to study the influence of these conditions during microwave cooking on the human bioactive compounds of broccoli. The results show a general decrease in the levels of all the studied compounds except for mineral nutrients which were stable under all cooking conditions. Vitamin C showed the greatest losses mainly because of degradation and leaching, whereas losses for phenolic compounds and glucosinolates were mainly due to leaching into water. In general, the longest microwave cooking time and the higher volume of cooking water should be avoided to minimize losses of nutrients. 相似文献
537.
The link between rheological behavior and morphological‐structural characteristics of gelatinized starch granules has been studied in two starch dispersions (SDs): a cross‐linked waxy maize (CLWM), and tapioca starch, a tuber starch with 19.3 % amylose. Based on the power law relationship between the elastic modulus and volume fraction of the granules predicted by scaling theory, fractal dimension values were obtained for CLWM starch D = 2.81, and tapioca starch D = 2.79, suggesting that both starch granules have highly convoluted surfaces. However, the preexponential coefficient (G′⊘=1) for CLWM SDs was an order of magnitude greater than that for tapioca SDs, in the same range of volume fractions. The G′⊘=1 was mainly dependent on the granule rigidity, and the amylose content in the continuous phase played only a minor role in the rheological behavior. 相似文献