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991.
The synthetic utility of tris-((2-hydroxybenzyl)-aminoethyl)amine (H6TrenSal) and tris-((2-hydroxy-5-bromobenzyl)-aminoethyl)amine (H6Tren5BrSal) are investigated. A range of monomeric complexes with general formula [(H6TrenSal)M][NO3] with nickel, copper and zinc are reported and crystallographically analysed. Nickel adopts three motifs which are different to that observed for copper and zinc. The use of these species as platforms for the synthesis of more complex systems in conjunction with the lanthanoids are explored. Copper and zinc do not follow a similar reaction pathway to nickel. While nickel forms the expected trimetallic motif [{(TrenSal)Ni}2Ln(HOMe)]+, copper forms a copper trimetallic motif. In contrast to both nickel and copper, reactions with [(H6TrenSal)Zn]+ produce lanthanoid based products namely [(H6Tren5BrSal)Gd(NO3)3] and [{(H6TrenSal)Ce}2-μ2-O2]. 相似文献
992.
993.
R.L. Konger S.D. Billings N.C. Prall T.M. Katona S.C. DaSilva C.R.J. Kennedy S. Badve S.M. Perkins P.T. LaCelle 《Prostaglandins, leukotrienes, and essential fatty acids》2009,81(4):279-290
We have previously demonstrated that the EP1 subtype of PGE2 receptor is expressed in the differentiated compartment of normal human epidermis and is coupled to intracellular calcium mobilization. We therefore hypothesized that the EP1 receptor is coupled to keratinocyte differentiation. In in vitro studies, radioligand binding, RT-PCR, immunoblot and receptor agonist-induced second messenger studies demonstrate that the EP1 receptor is up-regulated by high cell density in human keratinocytes and this up-regulation precedes corneocyte formation. Moreover, two different EP1 receptor antagonists, SC51322 and AH6809, both inhibited corneocyte formation. SC51322 also inhibited the induction of differentiation-specific proteins, cytokeratin K10 and epidermal transglutaminase. We next examined the immunolocalization of the EP1 receptor in non-melanoma skin cancer in humans. Well-differentiated SCCs exhibited significantly greater membrane staining, while spindle cell carcinomas and BCCs had significantly decreased membrane staining compared with normal epidermis. This data supports a role for the EP1 receptor in regulating keratinocyte differentiation. 相似文献
994.
Robert H. Rice Edgar A. Vidrio Qin Qin Ian M. Kennedy 《Chemico-biological interactions》2009,181(3):359-365
The present work describes a two-stage approach to analyzing combustion-generated samples for their potential to produce oxidant stress. This approach is illustrated with the two commonly encountered transition metals, copper and iron. First, their abilities to generate hydroxyl radical were measured in a cell-free, phosphate-buffered saline solution containing ascorbate and/or citrate. Second, their abilities to induce heme oxygenase-1 in cultured human epidermal keratinocytes were assessed in cell culture. Combustion-generated copper oxide nanoparticles were active in both assays and were found to be soluble in culture medium. Depletion of glutathione in the cells or loading the cells with ascorbate greatly increased heme oxygenase-1 induction in the presence of copper. By contrast, iron oxide nanoparticles were active in the phosphate-buffered saline but not in cell culture, and they aggregated in culture medium. Soluble salts of copper and iron exhibited the same contrast in activities as the respective combustion-generated particles. The results suggest that the capability of combustion-generated environmental samples to produce oxidant stress can be screened effectively in a two step process, first in phosphate-buffered saline with ascorbate and subsequently in epithelial cell culture for those exhibiting activity initially. The results also point to an unanticipated interaction in cells of oxidant stress-generating metals with an antioxidant (ascorbate) that is usually missing in culture medium formulations. Thus, ascorbate supplementation of cultured human cells is likely to improve their ability to model the in vivo effects of particulate matter containing copper and other redox-active metals. 相似文献
995.
Khaled A. Nasr Christian R. Schubert Marianna Török Robert J. Kennedy Daniel S. Kemp 《Biopolymers》2009,91(5):311-320
The natural amino acids are primarily helix breakers at the low assignment temperatures characteristic of many studies, but recent genomic analyses of thermophilic proteins suggest that at high temperatures, some breakers may become strong helix formers. Moreover, the breaker/former inventory has not been previously characterized at the physiologically relevant temperature of 37°C. The versatility of 13C?O NMR chemical shifts as helicity reporters allows construction of two mutant peptide series, tailored to expand the range of temperature assignments for helical propensities and derived from the core hosts tL‐Ala9XxxAla9‐tL and tL‐AlaNva4XxxNva4Ala9‐tL, Nva = norvaline. For three limiting guests Xxx, the helix former Nva and the breakers Gly and Pro, we report wXxx[T] assignments at seven temperatures from 2 to 80°C, validating our reasoning and paving the way for assignment of a definitive wXxx[T] data‐base. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 311–320, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com 相似文献
996.
Eggs were taken from adult sockeye salmon Oncorhynchus nerka that had reached their journey's end in spawn-ready and moribund condition, and fertilized by healthy males. Egg number, size, hatching success and offspring growth did not differ with maternal condition, which suggests the absence of any persisting physiological maternal effects. Differences were noted in the swimming behaviour and physiology of the offspring at parr stage. In a 30 min schooling test conducted using groups of five in a flume, parr from moribund females were more likely to fatigue, were not as tightly schooled, and had a diminished startle response, both in the per cent responding and the burst distance. In individual, confined swimming tests conducted within a tube, post-exercise plasma lactate concentration, which is an indicator of white muscle use, was greater for parr from moribund adult females. The moribund females also had elevated lactate following exercise (their migration), which suggests heritable differences may exist in muscle use. This study shows that juvenile O. nerka artificially propagated from females exhausted by their return migration can exhibit swimming performance differences, indicating that maternal condition may need to be considered in breeding programmes. 相似文献
997.
Shim J Moulson CL Newberry EP Lin MH Xie Y Kennedy SM Miner JH Davidson NO 《Journal of lipid research》2009,50(3):491-500
FA transport protein 4 (FATP4), one member of a multigene family of FA transporters, was proposed as a major FA transporter in intestinal lipid absorption. Due to the fact that Fatp4(-/-) mice die because of a perinatal skin defect, we rescued the skin phenotype using an FATP4 transgene driven by a keratinocyte-specific promoter (Fatp4(-/-);Ivl-Fatp4(tg/+) mice) to elucidate the role of intestinal FATP4 in dietary lipid absorption. Fatp4(-/-);Ivl-Fatp4(tg/+) mice and wild-type littermates displayed indistinguishable food consumption, growth, and weight gain on either low or high fat (Western) diets, with no differences in intestinal triglyceride (TG) absorption or fecal fat losses. Cholesterol absorption and intestinal TG absorption kinetics were indistinguishable between the genotypes, although Western diet fed Fatp4(-/-);Ivl-Fatp4(tg/+) mice showed a significant increase in enterocyte TG and FA content. There was no compensatory upregulation of other FATP family members or any other FA or cholesterol transporters in Fatp4(-/-);Ivl-Fatp4(tg/+) mice. Furthermore, although serum cholesterol levels were lower in Fatp4(-/-);Ivl-Fatp4(tg/+) mice, there was no difference in hepatic VLDL secretion in-vivo or in hepatic lipid content on either a chow or Western diet. Taken together, our studies find no evidence for a physiological role of intestinal FATP4 in dietary lipid absorption in mice. 相似文献
998.
Homogeneous modification of cellulose with succinic anhydride in ionic liquid using 4-dimethylaminopyridine as a catalyst 总被引:3,自引:0,他引:3
W.Y. Li A.X. Jin C.F. Liu R.C. Sun A.P. Zhang J.F. Kennedy 《Carbohydrate polymers》2009,78(3):389-395
Cellulose, extracted from sugarcane bagasse, was successfully succinylated in ionic liquid 1-buty-3-methylimidazolium (BMIMCl) using 4-dimethylaminopyridine (DMAP) as a catalyst. Parameters investigated included the mass ratio of DMAP/succinic anhydride in a range from 0% to 15%, reaction time (from 30 to 120 min), reaction temperature (from 60 to 110 °C). The succinylated cellulosic derivatives had a degree of substitution (DS) ranging from 0.24 to 2.34. It was found that the DS of succinylated cellulosic derivatives using DMAP as a catalyst was higher than that without any catalyst under the same reaction conditions. The products were characterized by FT-IR, solid-state CP/MAS 13C NMR, and thermal analysis. FT-IR and solid-state CP/MAS 13C NMR spectra showed that succinoylation occurred at C-6, C-2 and C-3 positions. The thermal stability of the succinylated cellulose decreased upon chemical modification. 相似文献
999.
Craig S. Nunemaker John F. Dishinger Stacey B. Dula Runpei Wu Matthew J. Merrins Kendra R. Reid Arthur Sherman Robert T. Kennedy Leslie S. Satin 《PloS one》2009,4(12)
We reported previously that islets isolated from individual, outbred Swiss-Webster mice displayed oscillations in intracellular calcium ([Ca2+]i) that varied little between islets of a single mouse but considerably between mice, a phenomenon we termed “islet imprinting.” We have now confirmed and extended these findings in several respects. First, imprinting occurs in both inbred (C57BL/6J) as well as outbred mouse strains (Swiss-Webster; CD1). Second, imprinting was observed in NAD(P)H oscillations, indicating a metabolic component. Further, short-term exposure to a glucose-free solution, which transiently silenced [Ca2+]i oscillations, reset the oscillatory patterns to a higher frequency. This suggests a key role for glucose metabolism in maintaining imprinting, as transiently suppressing the oscillations with diazoxide, a KATP-channel opener that blocks [Ca2+]i influx downstream of glucose metabolism, did not change the imprinted patterns. Third, imprinting was not as readily observed at the level of single beta cells, as the [Ca2+]i oscillations of single cells isolated from imprinted islets exhibited highly variable, and typically slower [Ca2+]i oscillations. Lastly, to test whether the imprinted [Ca2+]i patterns were of functional significance, a novel microchip platform was used to monitor insulin release from multiple islets in real time. Insulin release patterns correlated closely with [Ca2+]i oscillations and showed significant mouse-to-mouse differences, indicating imprinting. These results indicate that islet imprinting is a general feature of islets and is likely to be of physiological significance. While islet imprinting did not depend on the genetic background of the mice, glucose metabolism and intact islet architecture may be important for the imprinting phenomenon. 相似文献
1000.
Gaetano T. Montelione Cheryl Arrowsmith Mark E. Girvin Michael A. Kennedy John L. Markley Robert Powers James H. Prestegard Thomas Szyperski 《Journal of structural and functional genomics》2009,10(2):101-106
This Perspective, arising from a workshop held in July 2008 in Buffalo NY, provides an overview of the role NMR has played
in the United States Protein Structure Initiative (PSI), and a vision of how NMR will contribute to the forthcoming PSI-Biology
program. NMR has contributed in key ways to structure production by the PSI, and new methods have been developed which are
impacting the broader protein NMR community. 相似文献