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J R Lakowicz J Ku?ba W Wiczk I Gryczynski H Szmacinski M L Johnson 《Biophysical chemistry》1991,39(1):79-84
We report the first resolution of both the conformational distribution and end-to-end diffusion coefficient of a flexible molecule. This molecular information was recovered using only the donor intensity decay in a single solvent at a single viscosity, as observed by the technique of frequency-domain fluorometry. This technique can be extended to measurements of structural fluctuations of biological macromolecules. 相似文献
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Our studies aimed at determining a loss of active heparin from the peritoneal cavity after its intraperitoneal administration (250 JU/l of dialysis fluid) in 16 patients treated because of the end-stage renal failure with intermittent peritoneal dialysis and at comparing heparin influx clearance with that of glucose. It has been shown that heparin used in this dose loses 60-70% of its activity after 20-minute equilibration of dialysis fluid in the peritoneal cavity. Heparin influx clearance is higher than that of glucose but it depends on utilization of heparin in peritoneal cavity rather than on its penetration to the blood circulation. 相似文献
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Katharine Y. Ku Fred R. Butcher 《Biochimica et Biophysica Acta (BBA)/General Subjects》1980,631(1):70-78
Calmodulin coupled to Sepharose has provided a rapid and sensitive means of isolating a cyclic nucleotide phosphodiesterase activity which is stimulated by the calmodulin-Ca2+ complex, from rat parotid gland. Initial experiments established that phosphodiesterase activity sensitive to calmodulin and Ca2+ could not be demonstrated in crude extracts of rat parotid gland or after partial purification of rat parotid phosphodiesterase over DEAE-cellulose. However, it was possible to readily demonstrate the presence of a cyclic nucleotide phosphodiesterase activity regulated by calmodulin if the extracts were first purified by batch ion-exchange chromatography over DEAE-cellulose followed by affinity chromatography with calmodulin coupled to Sepharose. The batch ion-exchange chromatography step removed the major portion of free parotid calmodulin which could compete with calmodulin-coupled Sepharose for the proteins regulated by calmodulin. Thus, by employing an initial chromatography step over DEAE-cellulose to separate phosphodiesterase activity from calmodulin, it was possible to increase the recovery of calmodulin-sensitive phosphodiesterase after affinity chromatography with calmodulin coupled to Sepharose. This approach should be useful for demonstrating the presence of and for purifying other parotid proteins regulated by calmodulin. 相似文献
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Piotr Politański Elźbieta Rajkowska Marcin Brodecki Andrzej Bednarek Marek Zmyślony 《Bioelectromagnetics》2013,34(4):333-336
The aim of this study was to investigate the effect of static magnetic fields (SMF) on reactive oxygen species induced by X‐ray radiation. The experiments were performed on lymphocytes from male albino Wistar rats. After exposure to 3 Gy X‐ray radiation (with a dose rate of 560 mGy/min) the measurement of intracellular reactive oxygen species in lymphocytes, using a fluorescent probe, was done before exposure to the SMF, and after 15 min, 1 and 2 h of exposure to the SMF or a corresponding incubation time. For SMF exposure, 0 mT (50 µT magnetic field induction opposite to the geomagnetic field) and 5 mT fields were chosen. The trend of SMF effects for 0 mT was always opposite that of 5 mT. The first one decreased the rate of fluorescence change, while the latter one increased it. Bioelectromagnetics 34:333–336, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
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In vitro as well as in vivo evaluation of the reactivating efficacy of various oximes against nerve agent-inhibited acetylcholinesterase has been usually done with the help of animal experiments. Nevertheless, previously published data indicate that the reactivation potency of oximes may be different in human and animal species, which may hamper the extrapolation of animal data to human data. Therefore, to better evaluate the efficacy of various oximes (pralidoxime, obidoxime, HI-6, K033) to reactivate brain acetylcholinesterase inhibited by sarin by in vitro methods, human, rat and pig brain acetylcholinesterase were used to calculate kinetic parameters for the reactivation. Our results show differences among the species, depending on the type of oxime, and indicate that data from animal experiments needs to be carefully evaluated before extrapolation to humans. 相似文献
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High-resolution genetic and physical maps were constructed for the region of chromosome 2 containing the major fruit-shape locus ovate. A total of 3,000 NIL F2 and F3 NILs derived from Lycopersicon esculentum cv. Yellow Pear (TA503) x L. pennellii (a wild tomato) were used to position ovate adjacent to the marker TG645 and flanked by markers TX700 and BA10R (a 0.03-cM interval). BAC libraries and a BIBAC library were screened with the closest marker, TG645. Genetic mapping with the ends of isolated BAC clones revealed that two BAC clones (100 and 140 kb) both contained the ovate locus. Screening of sequences from these BAC clones revealed synteny between this segment of tomato chromosome 2 and the chromosome-4 region of Arabidopsis containing the BAC clone ATAP22. Microsynteny between the two genomes was exploited to find additional markers near the ovate locus. The placement of ovate on a BAC clone will now allow cloning of this locus and, hence, may open the door to understanding the molecular basis of fruit development and also facilitate the genetic engineering of fruit-shape characteristics. This also represents the first time that microsynteny with Arabidopsis has been exploited for positional cloning purposes in a different plant family. 相似文献