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51.
C. Vidal J.F. Menudet P. Cinquin J. Troccaz G. Morel J. Szewczyk J.J. Rambeaud J.A. Long P. Mozer 《IRBM》2010,31(2):122-126
This article presents work carried out as part of the robot sécurisé d’assistance à la chirurgie endoscopique (Rosace) project (funding ANR TecSan06), involving both academic and clinical partners along with an industrial partner in charge of technology integration. The main subject is a lightweight and compact robot for assistance in the endoscopic surgery field. The goal of the project has been to improve then transfer on a medical-grade product some technologies initially developed by the two academic partners. These technologies are: a first prototype of a robotic endoscope holder, an original method for visual servoing based on instrument tracking and some work done on comanipulation concept which consists in synergic interaction between robot and user. In accordance with the initial goals, major improvements have been obtained on these three aspects of the project. Robotic architecture improvement has contributed to enhance robot's versatility while robot command has been made more efficient and simple to use thanks to instrument tracking and comanipulation. After this 3-year project, initial prototype has turned into a commercially available product integrating (or that will integrate in a few months) these new technologies. 相似文献
52.
JC. Brisset F. Gazeau C. Corot N. Nighoghossian Y. Berthezène E. Canet-Soulas M. Wiart 《IRBM》2018,39(2):93-102
Background
Inflammation is a share process in atherosclerosis and stroke and is thought to be a key player in the evolution of these diseases. Ten years ago, inflammation imaging with magnetic resonance imaging (MRI) was considered very promising for both pre-clinical and clinical studies of atherosclerosis and stroke.Contribution
We report here contributions to the field of inflammation imaging with USPIO-enhanced MRI. The goal was to investigate the life cycle of USPIOs in the body, and how the MRI signal has been impacted during their bio-interactions and bioprocessing. Those mechanisms were applied to pre-clinical longitudinal studies of inflammation in atherosclerosis and at the acute stage of ischemic stroke thus allowing the monitoring of treatment effects.Conclusion
This review presents the contribution of the collaborative research project under the “TecSan” grant from the French Research Agency (ANR) as well as pre-clinical and clinical perspectives of USPIO's inflammation MRI in atherosclerosis and stroke. 相似文献53.
Wojciech Giera Sebastian Szewczyk Michael D. McConnell Kevin E. Redding Rienk van Grondelle Krzysztof Gibasiewicz 《Photosynthesis research》2018,137(2):321-335
Energetic properties of chlorophylls in photosynthetic complexes are strongly modulated by their interaction with the protein matrix and by inter-pigment coupling. This spectral tuning is especially striking in photosystem I (PSI) complexes that contain low-energy chlorophylls emitting above 700 nm. Such low-energy chlorophylls have been observed in cyanobacterial PSI, algal and plant PSI–LHCI complexes, and individual light-harvesting complex I (LHCI) proteins. However, there has been no direct evidence of their presence in algal PSI core complexes lacking LHCI. In order to determine the lowest-energy states of chlorophylls and their dynamics in algal PSI antenna systems, we performed time-resolved fluorescence measurements at 77 K for PSI core and PSI–LHCI complexes isolated from the green alga Chlamydomonas reinhardtii. The pool of low-energy chlorophylls observed in PSI cores is generally smaller and less red-shifted than that observed in PSI–LHCI complexes. Excitation energy equilibration between bulk and low-energy chlorophylls in the PSI–LHCI complexes at 77 K leads to population of excited states that are less red-shifted (by ~?12 nm) than at room temperature. On the other hand, analysis of the detection wavelength dependence of the effective trapping time of bulk excitations in the PSI core at 77 K provided evidence for an energy threshold at ~?675 nm, above which trapping slows down. Based on these observations, we postulate that excitation energy transfer from bulk to low-energy chlorophylls and from bulk to reaction center chlorophylls are thermally activated uphill processes that likely occur via higher excitonic states of energy accepting chlorophylls. 相似文献
54.
Nonneutral evolution of tandem repeats in the mitochondrial DNA control region of lagomorphs 总被引:7,自引:0,他引:7
Casane D; Dennebouy N; de Rochambeau H; Mounolou JC; Monnerot M 《Molecular biology and evolution》1997,14(8):779-789
The mitochondrial DNA of the European rabbit (Oryctolagus cuniculus)
contains a tandem array of 153-bp repeats in the vicinity of the
replication origin of the H-stand. Variation among molecules in the number
of these repeats results in inter- and intraindividual length polymorphism
(heteroplasmy). Generally, in an individual, one predominant molecular type
is observed, the others representing a low percentage of the mtDNA content.
At the tissue level, we observe a particular distribution of this
polymorphism in the gonads compared with liver, kidneys, or brain, implying
a relationship between the differentiation status of the cells and the
types of new mtDNA molecules which appear and accumulate during lifetime.
Similar tandem repeats were also found in the mtDNA noncoding region of
European hares (Lepus europaeus), a cottontail (Sylvilagus floridanus), and
a pika (Ochotona rufescens). The lengths and the sequences of these units
evolve rapidly and in a concerted way, but the number of repeats is
maintained in a narrow range, and an internal 20-bp segment is highly
conserved. Constraints restrict the evolution of the primary sequence of
these repeated units, the number of which is probably controlled by a
stabilizing selection.
相似文献
55.
56.
Potassium channels have been discovered in the inner mitochondrial membrane of various cells. These channels can regulate the mitochondrial membrane potential, the matrix volume, respiration and reactive species generation. Therefore, it is believed that their activation is cytoprotective in various tissues. In our study, the single-channel activity of a large-conductance calcium-activated potassium channel (mitoBKCa) was measured by the patch-clamp technique on mitoplasts derived from mitochondria isolated from human glioma U-87 MG cells. Here, we show for the first time that mechanical stimulation of mitoBKCa channels results in an increased probability of channel opening. However, the mechanosensitivity of mitoBKCa channels was variable with some channels exhibiting no mechanosensitivity. We detected the expression of mechanosensitive BKCa-STREX exon in U-87 MG cells and hypotesize, based on previous studies demonstrating the presence of multiple BKCa splice variants that variable mechanosensitivity of mitoBKCa could be the result of the presence of diverse BKCa isoforms in mitochondria of U-87 MG cells. Our findings indicate the possible involvement of the mitoBKCa channel in mitochondria activities in which changes in membrane tension and shape play a crucial role, such as fusion/fission and cristae remodeling. 相似文献
57.
Izabela Kołodziejczyk Katarzyna Dzitko Rafał Szewczyk Małgorzata M. Posmyk 《Acta Physiologiae Plantarum》2016,38(6):146
Melatonin (N-acetyl-5-methoxytryptamine) has a great potential for plant biostimulation. Its role in plant physiology is intensively explored, and its important function in plant stress defence frequently underlined. Melatonin is particularly effective when applied as an additional factor of seed priming. In the presented research, hydroconditioning was chosen experimentally as optimal for maize (Zea mays L.) seeds. The following seed variants were compared: controlled non-treated, hydroprimed with water and hydroprimed with melatonin solutions 50 and 500 μM. To identify modifications in proteome of maize seeds caused by the applied hydroconditioning techniques, protein extracts of germinated seed embryos (24 h, 25 °C) were separated by 2D-PAGE. Next, obtained maps of proteomes were compared (statistically and graphically) using PDQuest software, and characteristic spots of proteins were analysed qualitatively by mass-spectrometric techniques and identified in the Mascot protein databases. Research helped to identify hydropriming-associated proteins, and for the first time those which were expressed only in the presence of melatonin. Study confirmed that suitably selected pre-sowing treatment with melatonin, by embryo proteome modification, effectively prepares plants to adverse environmental conditions. In melatonin treated seeds during the initial state of embryos growth, even under optimal conditions, additional antioxidative, detoxifying, anti-stresses proteins were synthesized. Moreover, the supply of energy from seed storage substances was pretty intensified. The presented results partially explain how melatonin acts in plant stress defence, and why plants with higher melatonin content have exhibited increased capacity for stress tolerance. 相似文献
58.
Distinguishing morphologically cryptic taxa, by definition, requires genetic data such as DNA sequences. However, DNA sequences may not be obtained easily for taxa from remote sites. Here we provide the details of a high-resolution melt-curve-based method using taxon-specific primers that can distinguish two taxa of Adélie penguins, and that will be usable in Antarctica when combined with some of the newly developed field-deployable thermal cyclers. We suggest that the wider adoption of field-deployable polymerase-chain-reaction-based techniques will enable faster assignation of haplotype to individuals in situ, and so allow the targeting of observations and sample collection to specimens relevant to the research question. Targeting individuals will also reduce the need to repeatedly handle animals and reduce the time and travel required to complete field work. 相似文献
59.
Malekova L Kominkova V Ferko M Stefanik P Krizanova O Ziegelhöffer A Szewczyk A Ondrias K 《Biochimica et biophysica acta》2007,1767(1):31-44
The aim of this work was to characterize the effect of bongkrekic acid (BKA), atractyloside (ATR) and carboxyatractyloside (CAT) on single channel properties of chloride channels from mitochondria. Mitochondrial membranes isolated from a rat heart muscle were incorporated into a bilayer lipid membrane (BLM) and single chloride channel currents were measured in 250/50 mM KCl cis/trans solutions. BKA (1-100 microM), ATR and CAT (5-100 microM) inhibited the chloride channels in dose-dependent manner. The inhibitory effect of the BKA, ATR and CAT was pronounced from the trans side of a BLM and it increased with time and at negative voltages (trans-cis). These compounds did not influence the single channel amplitude, but decreased open dwell time of channels. The inhibitory effect of BKA, ATR and CAT on the mitochondrial chloride channel may help to explain some of their cellular and/or subcellular effects. 相似文献
60.