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61.
Thérèse Vanden Driessche Ghislaine M. Petiau-de Vries Jean-Luc Guisset 《Biological Rhythm Research》2013,44(4):349-360
We were able to demonstrate the presence of F 2,6-BP in Acetabularia in 7 out of 7 experiments. The amount varies between 4 and 38 pmole par mg protein. We were not able to evidence a circadian rhythm (CR) in its content. However, important fluctuations occur.(Fig. 1). This, of course excludes any precise conclusion about absolute amounts. Biologically active substances often exert an action modulated by circadian time. Thus, the effect of exogenous F 2,6-BP was assayed by fragmenting the long cell in F 2,6-BP-containing sea-water, and then follow growth and cap formation (we performed the experiment at different times during the 24 h cycle, in LD 12:12 conditions. Interestingly, the growth curves (obtained with 4 different concentrations) are statistically accelerated when the treatment had been performed at the beginning of the 24 h cycle (circadian time, CT, 0 is the transition time dark/light), less at CT 9.5, nul at CT 12 and again significant at CT 20. (Fig.IV). There is apparently no strictly defined light effect that could immediately modify the F-2,6-BP level, but there is presumably an important influence of CT-dependent physiological state of the alga. Again, it should be underlined that experimental biology should take time into account. 相似文献
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A newborn with the cat-eye syndrome 总被引:1,自引:0,他引:1
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Siamopoulou P Bimplakis A Iliopoulou D Vagias C Cos P Vanden Berghe D Roussis V 《Phytochemistry》2004,65(14):2025-2030
Nineteen secondary metabolites of the brown alga Dictyota dichotoma (Huds.) Lam. and fifteen metabolites of the brown alga D. linearis (Ag.) Grev. were isolated and their chemical structures were elucidated on the basis of their NMR and mass spectral data. The diterpenes isopachydictyolal (1) from D. dichotoma and 4alpha-acetyldictyodial (2) from D. linearis are new natural products. The antiviral activity of metabolites isolated in adequate amounts was evaluated in laboratory assays against Herpes simplex virus I (HSV I) and Poliomyelitis Virus I, using Vero cells as hosts. 相似文献
68.
Vanden Berghe P Hennig GW Smith TK 《American journal of physiology. Gastrointestinal and liver physiology》2004,286(4):G671-G682
Enteric neurons controlling various gut functions are prone to oxidative insults that might damage mitochondria (e.g., intestinal inflammation). To resume local energy supply, mitochondria need to be transported. We used MitoTracker dyes and confocal microscopy to investigate basic characteristics of mitochondrial transport in guinea pig myenteric neurites. During a 10-s observation of 1 mm nerve fiber, on average, three mitochondria were transported at an average speed of 0.41 +/- 0.02 microm/s. Movement patterns were clearly erratic, and velocities were independent of mitochondrial size. The velocity oscillated periodically ( approximately 6 s) but was not consistently affected by structures such as en route boutons, bifurcations, or stationary mitochondria. Also, mitochondria transported in opposite directions did not necessarily affect each others' mobility. Transport was blocked by microtubule disruption (100 microM colchicine), and destabilization (1 microM cytochalasin-D) or stabilization (10 microM phalloidin) of actin filaments, respectively, decreased (0.22 +/- 0.02 microm/s, P < 0.05) or increased (0.53 +/- 0.02 microm/s, P < 0.05) transport speed. Transport was inhibited by TTX (1 microM), and removal of extracellular Ca(2+) (plus 2 mM EGTA) had no effect. However, depletion of intracellular stores (thapsigargin) reduced (to 33%) and slowed the transport significantly (0.18 +/- 0.02 microm/s, P < 0.05), suggesting an important role for stored Ca(2+) in mitochondrial transport. Transport was also reduced (to 21%) by the mitochondrial uncoupler FCCP (1 microM) in a time-dependent fashion and slowed by oligomycin (10 microM). We conclude that mitochondrial transport is remarkably independent of structural nerve fiber properties. We also show that mitochondrial transport is TTX sensitive and speeds up by stabilizing actin and that functional Ca(2+) stores are required for efficient transport. 相似文献
69.
Infrared and colorimetry data suggest that bisbenzamidines connected by various rigid or flexible linkers are able to interact with heme in cell-free systems. At pH 5.0 the inhibition of formation of beta-hematin could be ascertained by infrared spectroscopy whereas at pH 7.0 the interaction yielded insoluble complexes for which a sandwich-type structure of stoichiometry 2:1, heme-drug, is tentatively proposed. 相似文献
70.
Vanden Eynde JJ Mayence A Huang TL Collins MS Rebholz S Walzer PD Cushion MT 《Bioorganic & medicinal chemistry letters》2004,14(17):4545-4548
A series of pentamidine congeners has been synthesized and screened for their in vitro activity against Pneumocystis carinii. Among the tested compounds, bisbenzamidines linked by a flexible pentanediamide or hexanediamide chain (7 and 9) emerged as exceptionally potent agents that were more effective and less toxic than pentamidine in the assays described in this study. 相似文献