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31.
Light emission in dinoflagellates is induced by water motions. But although it is known that mechanical stimulations of these organisms trigger the bioluminescent response, the exact mechanism that involves some cell membrane excitations by fluid motions is not yet fully understood and is still controversial. We show in this experimental study that the accelerated shear flow, created by abrupt rotations of one or both co-axial cylinders of a Couette shearing chamber excites the light emission from cultured dinoflagellates Pyrocystis lunula. Following our first results published earlier that state that pure laminar shear does not excite the main bioluminescent response in dinoflagellates, our present experiments show that both shear and acceleration in the flow are needed to trigger the bioluminescent response. Besides, the probability to stimulate this bioluminescent response under acceleration and shear is deduced from the response curves. This response follows a Gaussian distribution that traduces a heterogeneity in individual cell thresholds for the stimulation of bioluminescence in a dinoflagellate population. All these results will have a repercussion in the possible applications of dinoflagellate bioluminescence in flow visualizations and measurements. Moreover, this study opens a new way in studying mechanically-induced stimulus thresholds at the cell level. 相似文献
32.
Homozygous mutation in SPATA16 is associated with male infertility in human globozoospermia 总被引:1,自引:0,他引:1 下载免费PDF全文
Dam AH Koscinski I Kremer JA Moutou C Jaeger AS Oudakker AR Tournaye H Charlet N Lagier-Tourenne C van Bokhoven H Viville S 《American journal of human genetics》2007,81(4):813-820
Globozoospermia is a rare (incidence <0.1% in male infertile patients) form of teratozoospermia, mainly characterized by round-headed spermatozoa that lack an acrosome. It originates from a disturbed spermiogenesis, which is expected to be induced by a genetic factor. Several family cases and recessive mouse models with the same phenotype support this expectation. In this study, we present a consanguineous family with three affected brothers, in whom we have identified a homozygous mutation in the spermatogenesis-specific gene SPATA16. This is the first example of a nonsyndromic male infertility condition in humans caused by an autosomal gene defect, and it could also mean that the identification of other partners like SPATA16 could elucidate acrosome formation. 相似文献
33.
Genetic variability in nodulation and root growth affects nitrogen fixation and accumulation in pea 总被引:1,自引:0,他引:1
BACKGROUND AND AIMS: Legume nitrogen is derived from two different sources, symbiotically fixed atmospheric N(2) and soil N. The effect of genetic variability of root and nodule establishment on N acquisition and seed protein yield was investigated under field conditions in pea (Pisum sativum). In addition, these parameters were related to the variability in preference for rhizobial genotypes. METHODS: Five different spring pea lines (two hypernodulating mutants and three cultivars), previously identified in artificial conditions as contrasted for both root and nodule development, were characterized under field conditions. Root and nodule establishment was examined from the four-leaf stage up to the beginning of seed filling and was related to the patterns of shoot dry matter and nitrogen accumulation. The genetic structure of rhizobial populations associated with the pea lines was obtained by analysis of nodule samples. The fraction of nitrogen derived from symbiotic fixation was estimated at the beginning of seed filling and at physiological maturity, when seed protein content and yield were determined. KEY RESULTS: The hypernodulating mutants established nodules earlier and maintained them longer than was the case for the three cultivars, whereas their root development and nitrogen accumulation were lower. The seed protein yield was higher in 'Athos' and 'Austin', the two cultivars with increased root development, consistent with their higher N absorption during seed filling. CONCLUSION: The hypernodulating mutants did not accumulate more nitrogen, probably due to the C cost for nodulation being higher than for root development. Enhancing exogenous nitrogen supply at the end of the growth cycle, by increasing the potential for root N uptake from soil, seems a good option for improving pea seed filling. 相似文献
34.
Molecularly imprinted polymer films for reflectometric interference spectroscopic sensors 总被引:2,自引:0,他引:2
Belmont AS Jaeger S Knopp D Niessner R Gauglitz G Haupt K 《Biosensors & bioelectronics》2007,22(12):3267-3272
Reflectometric interference spectroscopic measurements were performed on molecularly imprinted polymer (MIP) films with the herbicide atrazine as the template molecule. A conventional imprinting protocol was used relying on non-covalent interactions between the functional monomers and the template. The MIPs were deposited on glass transducers by two different methods: spin-coating followed by in situ polymerization of thin films of monomers containing a sacrificial polymeric porogen, and autoassembly of MIP nanoparticles with the aid of an associative linear polymer. Reproducible results were obtained upon measurements of atrazine solutions in toluene with both films. Atrazine concentrations as low as 1.7 ppm could be detected with the autoassembled particle film. No or very little analyte adsorption was observed onto non-imprinted control films made by spin-coating and by particle assembly, respectively. We believe that these MIP layers in combination with the general reflectrometric transduction scheme could be a versatile sensing tool for the detection of environmentally important and other analytes. 相似文献
35.
36.
Mammalian protein-protein interaction trap (MAPPIT) analysis of STAT5, CIS, and SOCS2 interactions with the growth hormone receptor 总被引:1,自引:0,他引:1
37.
Virginie?Barraud-Lange Nathalie?Naud-Barriant Line?Saffar Liliane?Gattegno Beatrice?Ducot Anne-Sophie?Drillet Morgane?Bomsel Jean-Philippe?WolfEmail author Ahmed?Ziyyat 《BMC developmental biology》2007,7(1):102
Background
Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization. 相似文献38.
39.
Pierre F Stefan E Nédellec AS Chevrel MC Regan CF Siddiqui-Jain A Macalino D Streiner N Drygin D Haddach M O'Brien SE Anderes K Ryckman DM 《Bioorganic & medicinal chemistry letters》2011,21(22):6687-6692
A novel class of pan-Pim kinase inhibitors was designed by modifying the CK2 inhibitor CX-4945. Introduction of a triazole or secondary amide functionality on the C-7 position and 2'-halogenoanilines on C-5 resulted in potent inhibitors of the Pim-1 and Pim-2 isoforms, with many analogs active at single digit nanomolar concentrations. The molecules inhibited the phosphorylation at Serine 112 of the apoptosis effector BAD, and had potent antiproliferative effects on the AML cell line MV-4-11 (IC(50) <30 nM). This work delivers an excellent lead-optimization platform for Pim targeting anticancer therapies. 相似文献
40.
Mehta P Wavreille AS Justiniano SE Marsh RL Yu J Burry RW Jarjoura D Eubank T Caligiuri MA Butchar JP Tridandapani S 《PloS one》2011,6(6):e21175
SHIP and SHIP-2 are inositol phosphatases that regulate FcγR-mediated phagocytosis through catalytic as well as non-catalytic mechanisms. In this study we have used two-dimensional fluorescence difference gel electrophoresis (DIGE) analysis to identify downstream signaling proteins that uniquely associate with SHIP or SHIP-2 upon FcγR clustering in human monocytes. We identified LyGDI as a binding partner of SHIP, associating inducibly with the SHIP/Grb2/Shc complex. Immunodepletion and competition experiments with recombinant SHIP domains revealed that Grb2 and the proline-rich domain of SHIP were necessary for SHIP-LyGDI association. Functional studies in primary human monocytes showed that LyGDI sequesters Rac in the cytosol, preventing it from localizing to the membrane. Consistent with this, suppression of LyGDI expression resulted in significantly enhanced FcγR-mediated phagocytosis. 相似文献