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131.
132.
Lee L. Bernardis M. Bahorsky Luise Bohacek 《Cellular and molecular life sciences : CMLS》1966,22(10):671-673
Zusammenfassung Im Gegensatz zu weiblichen Ratten zeigen männliche Tiere mit Läsionen des N. ventromedialis hypothalami im Alter von 26, 59, 75 und 140 Tagen kurz nach der Ablaktation keinen unmittelbaren Einfluss auf die Futteraufnahme, Erwachsene nie die in den gleichaltrigen weiblichen Ratten beobachtete Hyperphagie. Männliche Ratten erreichen das Kontrollniveau schon nach 5 Wochen, während die weiblichen Tiere noch ausgeprägte Hyperphagic zeigen.
This investigation was supported by U.S.P.H.S. Grant No. HE 06975 of the National Heart Institute. 相似文献
This investigation was supported by U.S.P.H.S. Grant No. HE 06975 of the National Heart Institute. 相似文献
133.
L-Asparaginase activity in human and animal sera 总被引:1,自引:0,他引:1
134.
Zusammenfassung Nachweis, dass rezeptive Kortexfelder der Kaninchen (70% der visuellen Zellen) auf Lichtstimuli bzw. Schärfe-Unschärfe-Änderung mit Amplitudenabfall reagieren.
This work was supported by U.S.P.H.S. Grant No. EY00576. 相似文献
This work was supported by U.S.P.H.S. Grant No. EY00576. 相似文献
135.
Chee JL Guan XL Lee JY Dong B Leong SM Ong EH Liou AK Lim TM 《Cellular and molecular life sciences : CMLS》2005,62(2):227-238
Many have hypothesized that cell death in Parkinsons disease is via apoptosis and, specifically, by the mitochondrial-mediated apoptotic pathway. We tested this hypothesis using a mouse dopaminergic cell line of mesencephalic origin, MN9D, challenged with the Parkinsonism-causing neurotoxin MPP+ (1-methyl-4-phenylpyridinium ion). Apoptosis was the main mode of cell death when the cells were subjected to MPP+ treatment under serum-free conditions for 24 h. Caspase-3 and caspase-9, however, were not activated, thus indicating the existence of alternate or compensatory cell death pathway(s) in dopaminergic neuronal cells. Using caspase inhibitors, we demonstrated that these pathways involve caspase-2, –8, –6 and –7. A time-course study indicated that activation of caspase-2 and –8 occurred upstream of caspase-6 and caspase-7. Upon MPP+ challenge, the apoptosis-inducing factor was translocated from the mitochondria into the MN9D cytosol and nucleus. These results suggest the existence of alternative apoptotic pathways in dopaminergic neurons.Received 20 September 2004; received after revision 5 November 2004; accepted 22 November 2004 相似文献
136.
Jeon YH Heo YS Kim CM Hyun YL Lee TG Ro S Cho JM 《Cellular and molecular life sciences : CMLS》2005,62(11):1198-1220
Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.Received 30 November 2004; received after revision 24 January 2005; accepted 5 February 2005 相似文献
137.
Ménétrey J Bahloul A Wells AL Yengo CM Morris CA Sweeney HL Houdusse A 《Nature》2005,435(7043):779-785
Here we solve a 2.4-A structure of a truncated version of the reverse-direction myosin motor, myosin VI, that contains the motor domain and binding sites for two calmodulin molecules. The structure reveals only minor differences in the motor domain from that in plus-end directed myosins, with the exception of two unique inserts. The first is near the nucleotide-binding pocket and alters the rates of nucleotide association and dissociation. The second unique insert forms an integral part of the myosin VI converter domain along with a calmodulin bound to a novel target motif within the insert. This serves to redirect the effective 'lever arm' of myosin VI, which includes a second calmodulin bound to an 'IQ motif', towards the pointed (minus) end of the actin filament. This repositioning largely accounts for the reverse directionality of this class of myosin motors. We propose a model incorporating a kinesin-like uncoupling/docking mechanism to provide a full explanation of the movements of myosin VI. 相似文献
138.
Dynamics of Drosophila embryonic patterning network perturbed in space and time using microfluidics 总被引:1,自引:0,他引:1
Biochemical networks are perturbed both by fluctuations in environmental conditions and genetic variation. These perturbations must be compensated for, especially when they occur during embryonic pattern formation. Complex chemical reaction networks displaying spatiotemporal dynamics have been controlled and understood by perturbing their environment in space and time. Here, we apply this approach using microfluidics to investigate the robust network in Drosophila melanogaster that compensates for variation in the Bicoid morphogen gradient. We show that the compensation system can counteract the effects of extremely unnatural environmental conditions--a temperature step--in which the anterior and posterior halves of the embryo are developing at different temperatures and thus at different rates. Embryonic patterning was normal under this condition, suggesting that a simple reciprocal gradient system is not the mechanism of compensation. Time-specific reversals of the temperature step narrowed down the critical period for compensation to between 65 and 100 min after onset of embryonic development. The microfluidic technology used here may prove useful to future studies, as it allows spatial and temporal regulation of embryonic development. 相似文献
139.
Tuning clathrate hydrates for hydrogen storage 总被引:1,自引:0,他引:1
Lee H Lee JW Kim DY Park J Seo YT Zeng H Moudrakovski IL Ratcliffe CI Ripmeester JA 《Nature》2005,434(7034):743-746
The storage of large quantities of hydrogen at safe pressures is a key factor in establishing a hydrogen-based economy. Previous strategies--where hydrogen has been bound chemically, adsorbed in materials with permanent void space or stored in hybrid materials that combine these elements--have problems arising from either technical considerations or materials cost. A recently reported clathrate hydrate of hydrogen exhibiting two different-sized cages does seem to meet the necessary storage requirements; however, the extreme pressures (approximately 2 kbar) required to produce the material make it impractical. The synthesis pressure can be decreased by filling the larger cavity with tetrahydrofuran (THF) to stabilize the material, but the potential storage capacity of the material is compromised with this approach. Here we report that hydrogen storage capacities in THF-containing binary-clathrate hydrates can be increased to approximately 4 wt% at modest pressures by tuning their composition to allow the hydrogen guests to enter both the larger and the smaller cages, while retaining low-pressure stability. The tuning mechanism is quite general and convenient, using water-soluble hydrate promoters and various small gaseous guests. 相似文献
140.
Suppression of Polycomb group proteins by JNK signalling induces transdetermination in Drosophila imaginal discs 总被引:1,自引:0,他引:1
During the regeneration of Drosophila imaginal discs, cellular identities can switch fate in a process known as transdetermination. For leg-to-wing transdetermination, the underlying mechanism involves morphogens such as Wingless that, when activated outside their normal context, induce ectopic expression of the wing-specific selector gene vestigial. Polycomb group (PcG) proteins maintain cellular fates by controlling the expression patterns of homeotic genes and other developmental regulators. Here we report that transdetermination events are coupled to PcG regulation. We show that the frequency of transdetermination is enhanced in PcG mutant flies. Downregulation of PcG function, as monitored by the reactivation of a silent PcG-regulated reporter gene, is observed in transdetermined cells. This downregulation is directly controlled by the Jun amino-terminal kinase (JNK) signalling pathway, which is activated in cells undergoing regeneration. Accordingly, transdetermination frequency is reduced in a JNK mutant background. This regulatory interaction also occurs in mammalian cells, indicating that the role of this signalling cascade in remodelling cellular fates may be conserved. 相似文献