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51.
Michel Wright Catherine Albertini Viviane Planques Isabelle Salles Bernard Ducommun Catherine Gely Haleh Akhavan-Niaki Luis Mir Andr Moisand Marie-Louise Oustrin 《Biology of the cell / under the auspices of the European Cell Biology Organization》1988,63(2):239-248
Summary— The amoebae of the myxomycete Physarum polycephalum are of interest in order to analyze the morphogenesis of the microtubule and microfilament cytoskeleton during cell cycle and flagellation. The amoebal interphase microtubule cytoskeleton consists of 2 distinct levels of organization, which correspond to different physiological roles. The first level is composed of the 2 kinetosomes or centrioles and their associated structures. The anterior and posterior kinetosomes forming the anterior and posterior flagella are morphologically distinguishable. Each centriole plays a role in the morphogenesis of its associated satellites and specific microtubule arrays. The 2 distinct centrioles correspond to the 2 successive maturation stages of the pro-centrioles which are built during prophase. The second level of organization consists of a prominent microtubule organizing center (mtoc 1) to which the anterior centriole is attached at least during interphase. This mtoc plays a role in the formation of the mitotic pole. These observations based on ultrastructural and physiological analyses of the amoebal cystoskeleton are now being extended to the biochemical level. The complex formed by the 2 centrioles and the mtoc 1 has been purified without modifying the microtubule-nucleating activity of the mtoc 1. Several microtubule-associated proteins have been characterized by their ability to bind taxol-stabilized microtubules. Their functions (e.g., microtubule assembly, protection of microtubules against dilution or cold treatment, phosphorylating and ATPase activities) are under investigation. These biochemical approaches could allow in vitro analysis of the morphogenesis of the amoebal microtubule cytoskeleton. 相似文献
52.
Further progress towards a catalogue of all Arabidopsis genes: analysis of a set of 5000 non-redundant ESTs 总被引:9,自引:1,他引:8
Richard Cooke Monique Raynal Michele Laudi Franoise Grellet Michel Delseny Peter-Christian Morris Danile Guerrier Jrme Giraudat Franoise Quigley Grard Clabault You-Fang Li Rgis Mache Micheline Krivitzky Isabelle Jean-Jacques Gy Martin Kreis Alain Lecharny Yves Parmentier Jacqueline Marbach Jacqueline Fleck Bernadette Clment Gabriel Philipps Christine Herv Claude Bardet Dominique Tremousaygue Bernard Lescure Christophe Lacomme Dominique Roby Marie-Franoise Jourjon Patrick Chabrier Jean-Louis Charpenteau Thierry Desprez Joelle Amselem Helen Chiapello Herman Hfte 《The Plant journal : for cell and molecular biology》1996,9(1):101-124
Nearly 7000 Arabidopsis thaliana -expressed sequence tags (ESTs) from 10 cDNA libraries have been sequenced, of which almost 5000 non-redundant tags have been submitted to the EMBL data bank. The quality of the cDNA libraries used is analysed. Similarity searches in international protein data banks have allowed the detection of significant similarities to a wide range of proteins from many organisms. Alignment with ESTs from the rice systematic sequencing project has allowed the detection of amino acid motifs which are conserved between the two organisms, thus identifying tags to genes encoding highly conserved proteins. These genes are candidates for a common framework in genome mapping projects in different plants. 相似文献
53.
Rouquet N Allemand I Grimber G Molina T Briand P Joulin V 《Cell death and differentiation》1996,3(1):91-96
Apoptosis is crucial for the normal development of multicellular organisms and is also important for clearing injured cells, such as virus-infected cells or cancer cells. Defective regulation of apoptosis may contribute to viral pathogenesis and aetiology of cancer. Apoptosis of injured cells is principally triggered by the immune system through cytokines such as Fas-ligand and TNF-alpha. Thus, one of the functions of a viral oncogene, such as SV40T-antigen, may be to inhibit cytokine-mediated apoptosis. We previously demonstrated that Fas-mediated apoptosis of hepatocytes is blocked by the wild-type SV40T-antigen during hepatocarcinogenesis. We determined whether this inhibition was directly related to the T-antigen or whether it is a secondary event of cell transformation, by generating transgenic mice expressing a non-transforming T-antigen mutant able to bind endogenous p53 in the liver. This T-antigen mutant cannot induce hepatocarcinoma, unlike the wild-type T-antigen. However, like the wild-type T-antigen, the mutant was a potent inhibitor of apoptosis induced by the Fas-receptor, but not by the TNF-receptor. Therefore, SV40T-antigen has a new property; the inhibition of Fas-mediated apoptosis, which could facilitate the emergence of transformed hepatocytes, but is not sufficient to induce it. 相似文献
54.
Adle Martial Isabelle Gaillard Jean-Marc Engasser Annie Marc 《Enzyme and microbial technology》1995,17(12):1062-1066
A homemade serum-free medium containing a low protein level under 0.1 g l−1 has been proved to support long-term cultures of VO 208 hybridoma cells successfully up to 50 days. The low protein level was achieved by supplying the lipids through liposomes containing cholesterol, oleic acid,
- dipalmitoyl phosphatidylcholine, and bovine serum albumin. The influence of the liposome content in the feeding medium was studied in a continuous culture performed with step variations of the liposomes level, from 7.5 to 30 ml l−1. The cell density decreased at the highest liposomes content while it became higher with 7.5 or 12 ml l−1 of liposomes. For each step variation appeared a transitory activation of the specific rates of nutrient consumption, metabolite production and antibody secretion, as well as a transitory decrease of the specific cell growth rate. The overall structure of the antibodies was not affected during the culture. 相似文献
55.
Assessment of microinjection for introducing DNA into uninuclear microspores of rapeseed 总被引:3,自引:0,他引:3
Elizabeth Jones-Villeneuve Bin Huang Isabelle Prudhomme Sharon Bird Roger Kemble Jiro Hattori Brian Miki 《Plant Cell, Tissue and Organ Culture》1995,40(1):97-100
Approximately 2,000 embryogenic uninuclear microspores of rapeseed (Brassica napus) cv. Topas were intranuclearly injected with a chimaeric -glucuronidase (Escherichia coli Uid A) gene. Stable integration had not occurred among 55 plants that were regenerated. Coinjection of the dye Lucifer Yellow and detection of injected DNA by the polymerase chain reaction revealed high frequencies of transfer. However, the amount of DNA injected was less than 20 copies, which may have been insufficient for stable transformation of microspores.Abbreviations PCR
polymerase chain reaction
- GUS
-glucuronidase 相似文献
56.
Fatty acids of the scleractinian coral Galaxea fascicularis: effect of light and feeding 总被引:3,自引:0,他引:3
S. Al-Moghrabi D. Allemand J. M. Couret J. Jaubert 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1995,165(3):183-192
In order to investigate nutritional interactions in the symbiotic scleractinian coral-zooxanthella association, fatty acids of the coral Galaxea fascicularis were analysed in two groups of cultured microcolonies. The first group was fed with Artemia sp., while the second group was starved. After an initial 1-month period during which both groups were subjected to the same normal light conditions (constant irradiance of 125 E·cm-2·s-1 and 14:10 h light:dark), a light cap was used to cover the aquarium and keep all the microcolonies in permanent darkness for 20 days. During the light phase of the experiment it was shown that the nutritional status lead to large variations in the percentage of saturated, mono-unsaturated and polyunsaturated fatty acids. Palmitic acid (C16:0) was the most abundant fatty acid in both groups. Important differences between fed and starved microcolonies occurred during the dark phase of the experiment. In the fed group the dark phase was characterized by a significant increase in polyunsaturated fatty acids. Particularly arachidonic acid (C20:4 n-6) became the most important fatty acid followed by docosatrienoic acid (C22:3 n-3). A slight increase in these two fatty acids was also found in the starved group but the bulk of polyunsaturated fatty acids was significantly decreased. In this group, palmitic acid remained the most important fatty acid while an increased concentration of cis-vaccenic acid (C18:1 n-7) was found at the end of the experiment. The increased concentration of cis-vaccenic acid might indicate that bacteria serve as a source of energy. While the number of zooxanthellae per milligram of protein and the chlorophyll a to protein ratio strongly decreased in the starved microcolonies immediately after the beginning of the dark period, the decrease in fed microcolonies was delayed for about 10 days. Furthermore, after 20 days of dark incubation the chlorophyll a to protein ratio was the same as measured at the beginning of the dark period. This suggests that in the dark the metabolic requirements of the zooxanthellae are in part met from the animal host through a heterotrophic mode of nutrition.Abbreviations
CZ
cultured zooxanthellae
-
FAME
fatty acid methylester(s)
-
FDM
fed dark microcolonies
-
FLM
fed light microcolonies
-
MUFA
monounsaturated fatty acid(s)
-
PUFA
polyunsaturated fatty acid(s)
-
SDM
starved dark microcolonies
-
SFA
saturated fatty acids
-
SLM
starved-light microcolonies
-
SW
sea water
-
TFA
total fatty acids 相似文献
57.
Marie-Jos Navarro-Prigent Isabelle Sguin Pierre Boivin Didier Dhermy 《Biology of the cell / under the auspices of the European Cell Biology Organization》1995,83(1):33-38
Summary— The membrane skeleton, responsible for shape and mechanical properties of the red cell, was purified by the Triton extraction procedure in presence of 5 mM, 150 mM or 600 mM NaCl. The proportion of spectrin, protein 4.1 and actin present in erythrocyte skeletons does not depend on the molarity of NaCl used. In contrast ankyrin, protein band 3 and protein 4.2 are removed from skeletons as the ionic strength increased. Solubilization assays of membrane skeletons were used to study protein interactions inside the skeleton. Solubilization was performed by Tris, a non-selective disruptive reagent, or by p-mercuribenzene sulfonic acid (PMBS), which principally release spectrin and actin. Tris action was assessed by calculation of the percentage of solubilized proteins, which increased proportionally with Tris molarity. PMBS action was kinetically determined as the decrease in skeleton turbidity. With these two reagents, we observed a lower dissociation of skeletons prepared with high ionic strength buffer. Erythrocyte pretreatment with okadaic acid, an inhibitor of serine-threonine phosphatases, revealed a phosphorylation-induced skeleton gelation and a better resistance to Tris-solubilization. 相似文献
58.
Marc Pauly Isabelle Kayser Martine Schmitz Fernand Ries François Hentges Mario Dicato 《Journal of molecular evolution》1995,41(6):974-978
The mdr1 gene, first member of the human multidrug-resistance gene family, is a major gene involved in cellular resistance to several drugs used in anticancer chemotherapy. Its product, the drug-excreting P-glycoprotein, shows a bipartite structure formed by two similar adjacent halves. According to one hypothesis, the fusion of two related ancestral genes during evolution could have resulted in this structure. The DNA sequence analysis of the introns located in the region connecting the two halves of the human mdr1 gene revealed a highly conserved poly(CA) · poly (TG) sequence in intron 15 and repeated sequences of the Alu family in introns 14 and 17. These repeated sequences most likely represent molecular fossils of ancient DNA elements which were involved in such a recombination event.
Correspondence to: M. Pauly 相似文献
59.
Christine Heberden Thierry Mercier Isabelle Gaillard-Sanchez Brigitte Huet Paule Martel 《Experimental cell research》1995,218(2)
We assessed the presence and the role of membrane TGF-α in two rat liver epithelial cell lines, either parental or transfected with c-fos proto-oncogene. c-fos overexpressing cells had more TGF-α-like activity in their membranes. When TGF-α was removed by elastase or neutralized, the growth rates of both cell lines were markedly reduced, but to a higher extent for parental cells. If membrane TGF-α seemed to play a key contribution in normal cell growth, both cell lines were unable to react to the addition of soluble TGF-α, showing that these two forms of growth factors are not equivalent. 相似文献
60.