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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
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Pauline Ferraris Elodie Beaumont Rustem Uzbekov Denys Brand Julien Gaillard Emmanuelle Blanchard Philippe Roingeard 《Cellular and molecular life sciences : CMLS》2013,70(7):1297-1306
Like most positive-strand RNA viruses, hepatitis C virus (HCV) forms a membrane-associated replication complex consisting of replicating RNA, viral and host proteins anchored to altered cell membranes. We used a combination of qualitative and quantitative electron microscopy (EM), immuno-EM, and the 3D reconstruction of serial EM sections to analyze the host cell membrane alterations induced by HCV. Three different types of membrane alteration were observed: vesicles in clusters (ViCs), contiguous vesicles (CVs), and double-membrane vesicles (DMVs). The main ultrastructural change observed early in infection was the formation of a network of CVs surrounding the lipid droplets. Later stages in the infectious cycle were characterized by a large increase in the number of DMVs, which may be derived from the CVs. These DMVs are thought to constitute the membranous structures harboring the viral replication complexes in which viral replication is firmly and permanently established and to protect the virus against double-stranded RNA-triggered host antiviral responses. 相似文献
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Sensorimotor coordination emerges early in development. The maturation period is characterized by the establishment of somatotopic cortical maps, the emergence of long-range cortical connections, heightened experience-dependent plasticity and spontaneous uncoordinated skeletal movement. How these various processes cooperate to allow the somatosensory system to form a three-dimensional representation of the body is not known. In the visual system, interactions between spontaneous network patterns and afferent activity have been suggested to be vital for normal development. Although several intrinsic cortical patterns of correlated neuronal activity have been described in developing somatosensory cortex in vitro, the in vivo patterns in the critical developmental period and the influence of physiological sensory inputs on these patterns remain unknown. We report here that in the intact somatosensory cortex of the newborn rat in vivo, spatially confined spindle bursts represent the first and only organized network pattern. The localized spindles are selectively triggered in a somatotopic manner by spontaneous muscle twitches, motor patterns analogous to human fetal movements. We suggest that the interaction between movement-triggered sensory feedback signals and self-organized spindle oscillations shapes the formation of cortical connections required for sensorimotor coordination. 相似文献
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Marion Depla Rustem Uzbekov Christophe Hourioux Emmanuelle Blanchard Amélie Le Gouge Ludovic Gillet Philippe Roingeard 《Cellular and molecular life sciences : CMLS》2010,67(18):3151-3161
Hepatitis C virus (HCV) release is linked to the formation of lipid droplet (LD) clusters in the perinuclear area of infected
cells, induced by the core protein. We used electron microscopy (EM) to monitor and compare the number and size of LD in cells
producing the mature and immature forms of the HCV core protein, and 3D EM to reconstruct whole cells producing the mature
core protein. Only the mature protein coated the LD and induced their clustering and emergence from endoplasmic reticulum
membranes enriched in this protein. We found no particular association between LD clusters and the centrosome in reconstructed
cells. The LD clustering induced by the mature core protein was associated with an increase in LD synthesis potentially due,
at least in part, to the ability of this protein to coat the LD. These observations provide useful information for further
studies of the mechanisms involved in HCV-induced steatosis. 相似文献
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Valiullin R Naumov S Galvosas P Kärger J Woo HJ Porcheron F Monson PA 《Nature》2006,443(7114):965-968
In recent years, considerable progress has been made in the development of novel porous materials with controlled architectures and pore sizes in the mesoporous range. An important feature of these materials is the phenomenon of adsorption hysteresis: for certain ranges of applied pressure, the amount of a molecular species adsorbed by the mesoporous host is higher on desorption than on adsorption, indicating a failure of the system to equilibrate. Although this phenomenon has been known for over a century, the underlying internal dynamics responsible for the hysteresis remain poorly understood. Here we present a combined experimental and theoretical study in which microscopic and macroscopic aspects of the relaxation dynamics associated with hysteresis are quantified by direct measurement and computer simulations of molecular models. Using nuclear magnetic resonance techniques and Vycor porous glass as a model mesoporous system, we have explored the relationship between molecular self-diffusion and global uptake dynamics. For states outside the hysteresis region, the relaxation process is found to be essentially diffusive in character; within the hysteresis region, the dynamics slow down dramatically and, at long times, are dominated by activated rearrangement of the adsorbate density within the host material. 相似文献
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