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51.
Wound repair and regeneration 总被引:5,自引:0,他引:5
The repair of wounds is one of the most complex biological processes that occur during human life. After an injury, multiple biological pathways immediately become activated and are synchronized to respond. In human adults, the wound repair process commonly leads to a non-functioning mass of fibrotic tissue known as a scar. By contrast, early in gestation, injured fetal tissues can be completely recreated, without fibrosis, in a process resembling regeneration. Some organisms, however, retain the ability to regenerate tissue throughout adult life. Knowledge gained from studying such organisms might help to unlock latent regenerative pathways in humans, which would change medical practice as much as the introduction of antibiotics did in the twentieth century. 相似文献
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Boxma B de Graaf RM van der Staay GW van Alen TA Ricard G Gabaldón T van Hoek AH Moon-van der Staay SY Koopman WJ van Hellemond JJ Tielens AG Friedrich T Veenhuis M Huynen MA Hackstein JH 《Nature》2005,434(7029):74-79
Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolically quite different, just like mitochondria where large differences also exist. These differences have led to a continuing debate about the evolutionary origin of hydrogenosomes. Here we show that the hydrogenosomes of the anaerobic ciliate Nyctotherus ovalis, which thrives in the hindgut of cockroaches, have retained a rudimentary genome encoding components of a mitochondrial electron transport chain. Phylogenetic analyses reveal that those proteins cluster with their homologues from aerobic ciliates. In addition, several nucleus-encoded components of the mitochondrial proteome, such as pyruvate dehydrogenase and complex II, were identified. The N. ovalis hydrogenosome is sensitive to inhibitors of mitochondrial complex I and produces succinate as a major metabolic end product--biochemical traits typical of anaerobic mitochondria. The production of hydrogen, together with the presence of a genome encoding respiratory chain components, and biochemical features characteristic of anaerobic mitochondria, identify the N. ovalis organelle as a missing link between mitochondria and hydrogenosomes. 相似文献
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Summary The relation of the threshold current dose to the temperature constitutes a function of the chain-line type (hyperbolic function).From the dependence of the recovery time after galvanonarcosis upon the temperature it is concluded that by the passage of direct current molecular arrangements on surfaces are reversibly disturbed. 相似文献
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G T Werner 《Experientia》1979,35(11):1514-1515
Pretreatment with BCG yielded a high degree of protection against experimental vaccinia virus infections in mice. Corynebacterium parvum and Aristolochia acid were less protective; other immunostimulants were ineffective. 相似文献
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Werner Kuhn 《Cellular and molecular life sciences : CMLS》1947,3(8):315-318
Summary Some arguments put forward byG. Bier in a recent article in order to supportH. Staudinger's assumption that chain molecules in solution should behave like straight rigid rods are examined. It is shown that the assumptions made byG. Bier are largely arbitrary. The main argument is the assumption that the C-C-bond in long chain molecules should not show any rotation. As far as this point is concerned, attention is drawn to some recent publications showing that the viscosity of shape of chain molecules can be determined by experiment (specific viscosity and double refraction of flow at high velocity gradients). According to these determinations the time necessary for a complete change of shape, using partially free rotation, is of the order of 10–5–10–3 seconds for molecules like nitrocellulose or polystyrene up to degrees of polymerization of several thousands and for viscosities of the solvent of the order of 10–2 poises. 相似文献