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71.
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Jean-Charles Gabillard Cécile Rallière Nathalie Sabin Pierre-Yves Rescan 《BMC biotechnology》2010,10(1):39
Background
Fish skeletal muscle growth involves the activation of a resident myogenic stem cell population, referred to as satellite cells, that can fuse with pre-existing muscle fibers or among themselves to generate a new fiber. In order to monitor the regulation of myogenic cell differentiation and fusion by various extrinsic factors, we generated transgenic trout (Oncorhynchus mykiss) carrying a construct containing the green fluorescent protein reporter gene driven by a fast myosin light chain 2 (MlC2f) promoter, and cultivated genetically modified myogenic cells derived from these fish. 相似文献74.
75.
Concentrations and characteristics of procyanidins and other phenolics in apples during fruit growth 总被引:3,自引:0,他引:3
Apples (Malus domestica Borkh.) of two table and two cider cultivars were collected during fruit growth and maturation from the end of cell proliferation. Concentrations of flavonoids (flavan-3-ols, dihydrochalcones and flavonols) in the fruit flesh decreased sharply between circa 35 and circa 100 days after flowering. For hydroxycinnamic acids, the decrease appeared slower. In a second experiments apples of the cider cultivars Kermerrien and Avrolles were sampled every 2 weeks from 40 days after flowering to overripeness for a detailed characterisation of polyphenol accumulation kinetics in the fruit flesh. Most polyphenol synthesis had occurred at 40 days after full bloom, though it persisted at a low (Kermerrien) to very low (Avrolles) level during all the fruit growth. All qualitative characteristics of the polyphenols were remarkably stable. The degree of polymerisation of the procyanidins increased slightly in Avrolles and decreased in Kermerrien. This was accompanied by a relative increase in procyanidin B2, while size-exclusion chromatography of Kermerrien polyphenol extracts showed the disappearance of a highly polymerised fraction. 相似文献
76.
Earliest Triassic microbialites in the South China block and other areas: controls on their growth and distribution 总被引:9,自引:0,他引:9
Steve Kershaw Yue Li Sylvie Crasquin-Soleau Qinglai Feng Xinan Mu Pierre-Yves Collin Alan Reynolds Li Guo 《Facies》2007,53(3):409-425
Earliest Triassic microbialites (ETMs) and inorganic carbonate crystal fans formed after the end-Permian mass extinction (ca.
251.4 Ma) within the basal Triassic Hindeodus parvus conodont zone. ETMs are distinguished from rarer, and more regional, subsequent Triassic microbialites. Large differences
in ETMs between northern and southern areas of the South China block suggest geographic provinces, and ETMs are most abundant
throughout the equatorial Tethys Ocean with further geographic variation. ETMs occur in shallow-marine shelves in a superanoxic
stratified ocean and form the only widespread Phanerozoic microbialites with structures similar to those of the Cambro-Ordovician,
and briefly after the latest Ordovician, Late Silurian and Late Devonian extinctions. ETMs disappeared long before the mid-Triassic
biotic recovery, but it is not clear why, if they are interpreted as disaster taxa. In general, ETM occurrence suggests that
microbially mediated calcification occurred where upwelled carbonate-rich anoxic waters mixed with warm aerated surface waters,
forming regional dysoxia, so that extreme carbonate supersaturation and dysoxic conditions were both required for their growth.
Long-term oceanic and atmospheric changes may have contributed to a trigger for ETM formation. In equatorial western Pangea,
the earliest microbialites are late Early Triassic, but it is possible that ETMs could exist in western Pangea, if well-preserved
earliest Triassic facies are discovered in future work. 相似文献
77.
78.
Hepatitis B virus subviral envelope particle morphogenesis and intracellular trafficking 总被引:5,自引:0,他引:5
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Patient R Hourioux C Sizaret PY Trassard S Sureau C Roingeard P 《Journal of virology》2007,81(8):3842-3851
Hepatitis B virus (HBV) is unusual in that its surface proteins (small [S], medium, and large [L]) are not only incorporated into the virion envelope but they also bud into empty subviral particles in great excess over virions. The morphogenesis of these subviral envelope particles remains unclear, but the S protein is essential and sufficient for budding. We show here that, in contrast to the presumed model, the HBV subviral particle formed by the S protein self-assembles into branched filaments in the lumen of the endoplasmic reticulum (ER). These long filaments are then folded and bridged for packing into crystal-like structures, which are then transported by ER-derived vesicles to the ER-Golgi intermediate compartment (ERGIC). Within the ERGIC, they are unpacked and relaxed, and their size and shape probably limits further progression through the secretory pathway. Such progression requires their conversion into spherical particles, which occurred spontaneously during the purification of these filaments by affinity chromatography. Small branched filaments are also formed by the L protein in the ER lumen, but these filaments are not packed into transport vesicles. They are transported less efficiently to the ERGIC, potentially accounting for the retention of the L protein within cells. These findings shed light on an important step in the HBV infectious cycle, as the intracellular accumulation of HBV subviral filaments may be directly linked to viral pathogenesis. 相似文献
79.
Vidal A Sabatini M Rolland-Valognes G Renard P Madelmont JC Mounetou E 《Bioorganic & medicinal chemistry》2007,15(6):2368-2374
Among other non-antibiotic properties, tetracyclines inhibit matrix metalloproteinases and are currently under study for the treatment of osteoarthritis. Quaternary ammonium conjugates of tetracyclines were synthesized by direct alkylation of the amine function at the 4-position with methyl iodide. When tested in vitro, they inhibited cytokine-induced MMP expression to a lesser extent than parent tetracyclines. This was compensated by an improved inhibition of MMP catalytic activity. Since inhibition of collagen degradation was maintained these derivatives could be potent drug candidates for cartilage-targeted chondroprotective treatment. 相似文献
80.
Abstract. Individual marking has long been used in many fields of biology. However, capture–mark–recapture (CMR) studies are not evenly distributed among taxonomic groups, with most studies focusing on vertebrates. For example, a limited number of studies have been conducted in gastropods, in sharp contrast to their important role as biological models or exploited natural resources. The lack of standard, validated marking techniques certainly contributes to the limited use of CMR. In this article, we evaluate two fundamental requirements for a marking technique to be suitable, i.e., tag loss (two experiments) and impact on life-history traits (survival, growth, and fecundity, in three experiments). Five marking techniques for hard-shelled gastropods were tested in the freshwater snail Physa acuta (Pulmonata). The tag-loss rate per month was lower for glued plastic marks (0.01) than for paint marks (0.03–0.07), and the tag-loss rate varied among colors (gouache paint). Under laboratory conditions, the life-history traits were not significantly affected by marking. We thus recommend using glued plastic marks for long-term studies, and paint marks for mass marking, with double marking to account for tag-loss rate. Based on an extensive literature survey, we also review current CMR practices in gastropod studies and suggest general improvements that would prove useful in both this group and invertebrates in general. 相似文献