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1.
J L Baert 《European journal of biochemistry》1988,177(3):625-630
It has been shown previously in our laboratory that, in Perinereis cultrifera, the four mature vitellin subunits (Mr 98,000, 22,000, 20,000, 16,000) are proteolytically derived within the oocyte from a single extraoocytic precursor, vitellogenin, with an apparent Mr (176,000) higher by 20,000 than the sum of the Mr of the four end products. In this report, it is shown that a 15,000-Mr protein, designated as P15, not only accumulates in maturing oocytes but also originates from outside these cells similarly to vitellin. Moreover in vivo labelling experiments indicate that the appearance of P15 occurs after vitellogenin enters the oocyte, concurrently with the appearance of the lower-Mr fragments characteristic of vitellin. From these data, it is concluded that P15 most likely represents a vitellogenin-derived protein which is generated within the oocytes during the transformation of vitellogenin into vitellin. This conclusion is further supported by the additional finding that P15 immunologically cross-reacts with vitellogenin but not with mature vitellin. P15 has been purified to homogeneity from the soluble protein fraction of submature oocytes and partially characterized. The 15,000-Mr protein exists in a monomeric form with a pI of about 7.7. Unlike vitellin, P15 does not contain significant amounts of lipid or carbohydrate and has a low absorbance at 280 nm. The amino acid composition of the purified protein is also presented. 相似文献
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P Bonnier E Porchet-Hennere J L Baert 《Biology of the cell / under the auspices of the European Cell Biology Organization》1991,73(2-3):179-181
Coelomocytes of Nereis diversicolor synthesize and secrete vitellogenin in vitro. Using a monoclonal antibody which specifically recognized vitellogenin, we showed by immunocytochemistry that among the coelomocytes only a subpopulation, called eleocytes, contained vitellogenin. These results assert that eleocytes are the vitellogenin producing cells in nereids. 相似文献
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Frans van Cauwelaert Ignace Hanssens Willy Herreman Jean-Claude van Ceunebroeck Johan Baert Hugo Berghmans 《生物化学与生物物理学报:生物膜》1983,727(2):273-284
The characteristics of small unilamellar, large unilamellar and large multilamellar vesicles of dimyristoylphosphatidylcholine and their interaction with α-lactalbumin are compared at pH 4. (1) By differential scanning calorimetry and from steady-state fluorescence anisotropy data of the lipophilic probe 1,6-diphenyl-1,3,5-hexatriene it is shown that the transition characteristics of the phospholipids in the large unilamellar vesicles resemble more those of the multilamellar vesicles than of the small unilamellar vesicles. (2) The size and composition of the lipid-protein complex formed with α-lactalbumin around the transition temperature of the lipid are independent of the vesicle type used. Fluorescence anisotropy data indicate that in this complex the motions of the lipid molecules are strongly restricted in the presence of α-lactalbumin. (3) The previous data and a comparison of the enthalpy changes, , of the interaction of the three vesicle types with α-lactalbumin allow us to derive that the enthalpy state of the small unilamellar vesicles just below 24°C is about 24 kJ/mol lipid higher than the enthalpy state of both large vesicle types at the same temperature. The abrupt transition from endothermic to exothermic values around 24°C for large vesicles approximates the transition enthalpy of the pure phospholipid 相似文献
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Annelies Bronckaers Petra Hilkens Yanick Fanton Tom Struys Pascal Gervois Constantinus Politis Wendy Martens Ivo Lambrichts 《PloS one》2013,8(8)
Angiogenesis, the formation of capillaries from pre-existing blood vessels, is a key process in tissue engineering. If blood supply cannot be established rapidly, there is insufficient oxygen and nutrient transport and necrosis of the implanted tissue will occur. Recent studies indicate that the human dental pulp contains precursor cells, named dental pulp stem cells (hDPSC) that show self-renewal and multilineage differentiation capacity. Since these cells can be easily isolated, cultured and cryopreserved, they represent an attractive stem cell source for tissue engineering. Until now, only little is known about the angiogenic abilities and mechanisms of the hDPSC. In this study, the angiogenic profile of both cell lysates and conditioned medium of hDPSC was determined by means of an antibody array. Numerous pro-and anti-angiogenic factors such as vascular endothelial growth factor (VEGF), monocyte chemotactic protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1) and endostatin were found both at the mRNA and protein level. hDPSC had no influence on the proliferation of the human microvascular endothelial cells (HMEC-1), but were able to significantly induce HMEC-1 migration in vitro. Addition of the PI3K-inhibitor and the MEK-inhibitor U0126 to the HMEC-1 inhibited this effect, suggesting that both Akt and ERK pathways are involved in hDPSC-mediated HMEC-1 migration. Antibodies against VEGF also abolished the chemotactic actions of hDPSC. Furthermore, in the chicken chorioallantoic membrane (CAM) assay, hDPSC were able to significantly induce blood vessel formation. In conclusion, hDPSC have the ability to induce angiogenesis, meaning that this stem cell population has a great clinical potential, not only for tissue engineering but also for the treatment of chronic wounds, stroke and myocardial infarctions. LY294002相似文献
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Candy Kumps Annelies Fieuw Pieter Mestdagh Bj?rn Menten Steve Lefever Filip Pattyn Sara De Brouwer Tom Sante Johannes Hubertus Schulte Alexander Schramm Nadine Van Roy Tom Van Maerken Rosa Noguera Valérie Combaret Christine Devalck Frank Westermann Geneviève Laureys Angelika Eggert Jo Vandesompele Katleen De Preter Frank Speleman 《PloS one》2013,8(1)
Neuroblastoma is an embryonic tumor arising from immature sympathetic nervous system cells. Recurrent genomic alterations include MYCN and ALK amplification as well as recurrent patterns of gains and losses of whole or large partial chromosome segments. A recent whole genome sequencing effort yielded no frequently recurring mutations in genes other than those affecting ALK. However, the study further stresses the importance of DNA copy number alterations in this disease, in particular for genes implicated in neuritogenesis. Here we provide additional evidence for the importance of focal DNA copy number gains and losses, which are predominantly observed in MYCN amplified tumors. A focal 5 kb gain encompassing the MYCN regulated miR-17∼92 cluster as sole gene was detected in a neuroblastoma cell line and further analyses of the array CGH data set demonstrated enrichment for other MYCN target genes in focal gains and amplifications. Next we applied an integrated genomics analysis to prioritize MYCN down regulated genes mediated by MYCN driven miRNAs within regions of focal heterozygous or homozygous deletion. We identified RGS5, a negative regulator of G-protein signaling implicated in vascular normalization, invasion and metastasis, targeted by a focal homozygous deletion, as a new MYCN target gene, down regulated through MYCN activated miRNAs. In addition, we expand the miR-17∼92 regulatory network controlling TGFß signaling in neuroblastoma with the ring finger protein 11 encoding gene RNF11, which was previously shown to be targeted by the miR-17∼92 member miR-19b. Taken together, our data indicate that focal DNA copy number imbalances in neuroblastoma (1) target genes that are implicated in MYCN signaling, possibly selected to reinforce MYCN oncogene addiction and (2) serve as a resource for identifying new molecular targets for treatment. 相似文献
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