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31.
Julien Deschênes Jean-Paul Valet Normand Marceau 《In vitro cellular & developmental biology. Plant》1980,16(8):722-729
Summary The two-step collagenase perfusion method originally developed for the high yield isolation of parenchymal cells from adult
rat livers has been adapted to rats of 1 day, 1 week, and 3 weeks of age. The use of this method to isolate hepatocytes from
five or six rats of the respective ages demonstrated its reliability in terms of cell yield, percentage of single cells, and
cell viability. In all cases, hepatocytes attach with high efficiency to fibronectin precoated dishes using serum-free culture
medium. The dynamics of spreading is faster for newborn hepatocytes than adult ones. The functional integrity of these parenchymal
liver cells was assessed by their capacity to secrete albumin and α-fetoprotein in serum-free medium and to express lactate
dehydrogenase activity over a 24-hr period in primary culture.
Part of this work was presented at the 30th Annual Meeting of the Tissue Culture Association, Seattle, June, 1979. 相似文献
32.
R Julien J Rathelot P Canioni L Sarda T H Plummer 《Biochimica et biophysica acta》1975,379(1):157-163
1. The amino acid composition of bovine pancreatic lipase is very similar to that of porcine lipase. 2. Bovine lipase possesses a residue of lysine at the N-terminal position and a half cystine or a cysteine at the C-terminal position. 3. Bovine lipase contains two free sulfhydryl groups of different reactivities to 5, 5'-dithiobis-(2-nitrobenzoic) acid. One of these groups is buried in the native conformation of the enzyme and is fully titrated in 1.5 M urea when reaction is performed in the presense of 1 mM EDTA. 相似文献
33.
The bacterial Tn5 and Tn10 transposases have a single active site that cuts both strands of DNA at their respective transposon ends. This is achieved using a hairpin intermediate that requires the DNA to change conformation during the reaction. In Tn5 these changes are controlled in part by a flipped nucleoside that is stacked on a tryptophan residue in a hydrophobic pocket of the transposase. Here we have investigated the base flipping mechanism in Tn10 transposition. As in Tn5 transposition, we find that base flipping takes place after the first nick and is required for efficient hairpin formation and resolution. Experiments with an abasic substrate show that the role of base flipping in hairpin formation is to remove the base from the DNA helix. Specific interactions between the flipped base and the stacking tryptophan residue are required for hairpin resolution later in the reaction. We show that base flipping in Tn10 transposition is not a passive reaction in which a spontaneously flipped base is captured and retained by the protein. Rather, it is driven in part by a methionine probe residue that helps to force the flipped base from the base stack. Overall, it appears that base flipping in Tn10 transposition is similar to that in Tn5 transposition. 相似文献
34.
Nirvana Sadaghianloo Julie Contenti Maeva Dufies Julien Parola Matthieu Rouleau Shinrong Lee Jean-François Peyron Lucilla Fabbri Réda Hassen-Khodja Jacques Pouysségur Frédéric Bost Elixène Jean-Baptiste Alan Dardik Nathalie M. Mazure 《Journal of cellular and molecular medicine》2020,24(5):2931-2941
Arteriovenous fistulas (AVFs) are the preferred vascular access for haemodialysis of patients suffering from end-stage renal disease, a worldwide public health problem. However, they are prone to a high rate of failure due to neointimal hyperplasia and stenosis. This study aimed to determine if osteopontin (OPN) was induced in hypoxia and if OPN could be responsible for driving AVF failure. Identification of new factors that participate in remodelling of AVFs is a challenge. Three cell lines representing the cells of the three layers of the walls of arteries and veins, fibroblasts, smooth muscle cells and endothelial cells, were tested in mono- and co-culture in vitro for OPN expression and secretion in normoxia compared to hypoxia after silencing the hypoxia-inducible factors (HIF-1α, HIF-2α and HIF-1/2α) with siRNA or after treatment with an inhibitor of NF-kB. None of the cells in mono-culture showed OPN induction in hypoxia, whereas cells in co-culture secreted OPN in hypoxia. The changes in oxygenation that occur during AVF maturation up-regulate secretion of OPN through cell-cell interactions between the different cell layers that form AVF, and in turn, these promote endothelial cell proliferation and could participate in neointimal hyperplasia. 相似文献
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39.
Thibaut Capblancq Xavier Morin Maya Gueguen Julien Renaud Stphane Lobreaux Eric Bazin 《Journal of evolutionary biology》2020,33(6):783-796
Local adaptation patterns have been found in many plants and animals, highlighting the genetic heterogeneity of species along their range of distribution. In the next decades, global warming is predicted to induce a change in the selective pressures that drive this adaptive variation, forcing a reshuffling of the underlying adaptive allele distributions. For species with low dispersion capacity and long generation time such as trees, the rapidity of the change could impede the migration of beneficial alleles and lower their capacity to track the changing environment. Identifying the main selective pressures driving the adaptive genetic variation is thus necessary when investigating species capacity to respond to global warming. In this study, we investigate the adaptive landscape of Fagus sylvatica along a gradient of populations in the French Alps. Using a double‐digest restriction‐site‐associated DNA (ddRAD) sequencing approach, we identified 7,000 SNPs from 570 individuals across 36 different sites. A redundancy analysis (RDA)‐derived method allowed us to identify several SNPs that were strongly associated with climatic gradients; moreover, we defined the primary selective gradients along the natural populations of F. sylvatica in the Alps. Strong effects of elevation and humidity, which contrast north‐western and south‐eastern site, were found and were believed to be important drivers of genetic adaptation. Finally, simulations of future genetic landscapes that used these findings allowed identifying populations at risk for F. sylvatica in the Alps, which could be helpful for future management plans. 相似文献
40.
Julien Blanco Beatriz Belln Christo Fabricius Fabio de O. Roque Olivier Pays Franois Laurent Herv Fritz Pierre‐Cyril Renaud 《Global Change Biology》2020,26(3):1138-1154
Land‐use changes and the expansion of protected areas (PAs) have amplified the interaction between protected and unprotected areas worldwide. In this context, ‘interface processes' (human–nature and cross‐boundary interactions inside and around PAs) have become central to issues around the conservation of biodiversity and ecosystem services. This scientific literature review aimed to explore current knowledge and research gaps on interface processes regarding terrestrial PAs. At first, 3,515 references related to the topic were extracted through a standardized search on the Web of Science and analyzed with scientometric techniques. Next, a full‐text analysis was conducted on a sample of 240 research papers. A keyword analysis revealed a wide diversity of research topics, from ‘pure' ecology to sociopolitical research. We found a bias in the geographical distribution of research, with half the papers focusing on eight countries. Additionally, we found that the spatial extent of cross‐boundary interactions was rarely assessed, preventing any clear delimitation of PA interactive zones. In the 240 research papers we scanned, we identified 403 processes that were studied. The ecological effects of PAs were well documented and appeared to be positive overall. In contrast, the effects of PAs on local communities were understudied and, according to the literature focusing on these, were very variable according to local contexts. Our findings highlight key research advances on interface processes, especially regarding the ecological outcomes of PAs, the influence of human activities on biodiversity, and PA governance issues. In contrast, main knowledge gaps concern the spatial extent of interactive zones, as well as the interactions between local people and conservation actions and how to promote synergies between them. While the review was limited to terrestrial PAs, its findings allow us to propose research priorities for tackling environmental and socioeconomic challenges in the face of a rapidly changing world. 相似文献