排序方式: 共有48条查询结果,搜索用时 15 毫秒
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Nicanor I. Moldovan Florea Lupu Leni Moldovan Nicolae Simionescu 《Cell biology international》1994,18(10):985-992
Cultured bovine aortic endothelial cells (BAEC) were incubated for 5 days with 10?5 4-hydroxynonenal (HN). HN treated BAEC and controls were either (i) further incubated with 125I-polymyxin B (IPxB) or with radioiodinated, inactivated coagulation factor Xa (IFXai) as markers of membrane phospholipid perturbation, or (ii) assayed for the synthesis of prostacyclin (PGI2) and thromboxane A2 (TXA2). Rabbit blood mononuclear cells enriched in monocytes (MC) were isolated and assayed for chemotactic response to HN. The results showed six - fold increases of IPxB and IFXai binding to BAEC treated with HN, as compared to untreated controls. We also found in HN treated cells a marked inhibition of PGI2 synthesis, but an unmodified TXA2 production. In addition, HN in the 10-5-10-10 M range induced oriented migration of MC. 相似文献
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Neosparton darwinii Benth. & Hook. is a ramose, almost leafless shrub, whose growth is restricted to an area on the southwestern coast of Buenos Aires province (Argentina). Its limited distribution could imply risks for its survival. In the present study, we evaluated population characteristics relevant to an assessment of its conservation status and made a preliminary characterization of its habitat. Historical data seem to indicate that the species has undergone a severe reduction in its geographic distribution. We estimated the actual population size to be around 44,000 plants, distributed in a clumped pattern. We found no significant differences between the environments immediately associated with the plants and other similar distant sites, in terms of position on the dune profile, percentage of bare soil and the richness and composition of accompanying plant species. A high proportion of the seeds produced each year is destroyed by parasite bruchid beetles. We have not seen seedlings of N.darwinii in the area. All the laboratory germination essays done to date have produced negative results. The species grows in an area intensively used by tourists. We can foresee quantitative and qualitative reductions in habitat availability. This information points out that N.darwinii is not just a rare species, but its survival is a matter for serious consideration. We suggest certain steps towards effective management to ensure its conservation. 相似文献
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Jean‐Baptiste Coutelis Nicanor González‐Morales Charles Géminard Stéphane Noselli 《EMBO reports》2014,15(9):926-937
Differentiating left and right hand sides during embryogenesis represents a major event in body patterning. Left–Right (L/R) asymmetry in bilateria is essential for handed positioning, morphogenesis and ultimately the function of organs (including the brain), with defective L/R asymmetry leading to severe pathologies in human. How and when symmetry is initially broken during embryogenesis remains debated and is a major focus in the field. Work done over the past 20 years, in both vertebrate and invertebrate models, has revealed a number of distinct pathways and mechanisms important for establishing L/R asymmetry and for spreading it to tissues and organs. In this review, we summarize our current knowledge and discuss the diversity of L/R patterning from cells to organs during evolution. 相似文献
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Borja Mateos Ganeko Bernardo-Seisdedos Valentin Dietrich Nicanor Zalba Gabriel Ortega Francesca Peccati Gonzalo Jiménez-Osés Robert Konrat Martin Tollinger Oscar Millet 《Biophysical journal》2021,120(10):2067-2077
Protein oligomerization processes are widespread and of crucial importance to understand degenerative diseases and healthy regulatory pathways. One particular case is the homo-oligomerization of folded domains involving domain swapping, often found as a part of the protein homeostasis in the crowded cytosol, composed of a complex mixture of cosolutes. Here, we have investigated the effect of a plethora of cosolutes of very diverse nature on the kinetics of a protein dimerization by domain swapping. In the absence of cosolutes, our system exhibits slow interconversion rates, with the reaction reaching the equilibrium within the average protein homeostasis timescale (24–48 h). In the presence of crowders, though, the oligomerization reaction in the same time frame will, depending on the protein's initial oligomeric state, either reach a pure equilibrium state or get kinetically trapped into an apparent equilibrium. Specifically, when the reaction is initiated from a large excess of dimer, it becomes unsensitive to the effect of cosolutes and reaches the same equilibrium populations as in the absence of cosolute. Conversely, when the reaction starts from a large excess of monomer, the reaction during the homeostatic timescale occurs under kinetic control, and it is exquisitely sensitive to the presence and nature of the cosolute. In this scenario (the most habitual case in intracellular oligomerization processes), the effect of cosolutes on the intermediate conformation and diffusion-mediated encounters will dictate how the cellular milieu affects the domain-swapping reaction. 相似文献
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Moldovan NI 《Journal of cellular and molecular medicine》2005,9(4):775-776
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Micropatterning technology holds significant promise in the development of micro/nanomedical devices. The precise control of cell position and migration is important in several applications. For example, the optimal design of implantable devices depends on the implant material's micro-and nano-texture, which influences the response of nearby tissue, including the microvessels. Therefore, we were interested in endothelial cell positioning and colonization on specific surface domains in the size range of microvasculature. To this end, endothelial cells were seeded in microfabricated grooves and exposed to vascular endothelial growth factor (VEGF), which plays a key role in the angiogenic response. Patterned silicon wafers with grooves of 50 microm width and depth and 150 microm groove spacing were used. Each patterned region had two semicircular ports at either end, one of which was used to seed human retinal endothelial cells (HREC) and the other to house VEGF embedded in Matrigel. After 1 week, cells were fixed and analyzed by laser scanning cytometry (LSC). Our results shows that we can control HREC seeding and positioning in surface grooves and that the speed of colonization of the grooves can be manipulated by local VEGF application. We were able to quantify this effect, showing that HREC relocate inside the grooves twice as fast in response to VEGF stimulation, compared to control conditions, at a speed of 3.14 +/- 0.01 and 1.55 +/- 0.01 microm/min, respectively. Our approach could be used towards the fabrication of "designer" substrates or devices that not only allow patterned cell growth, but also permit dynamic cell repositioning. 相似文献
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La Sala Luciano F. Burgos Julián M. Scorolli Alberto L. VanderWaal Kimberly Zalba Sergio M. 《Biological invasions》2021,23(7):2063-2076
Biological Invasions - Invasive alien species (IAS) can act as vectors for the introduction of pathogens in ecosystems and their transmission to threatened native species (TNS), leading to... 相似文献