Abstract:The metallothionein(MT)was purified from the liver of Carassius auratus induced by exposure to cadmium chloride and characterized.It shows very similar to mammalian metallothioneins in all of its properties.The MT of the fish contains high cysteine contents(30%)and with an absence of aromatic acid residues.The thiol groups of the cysteine residues combine with the cadmium in SH/Cd molar ratio of 3∶1 and produce a characteristic absorption maxium at 250 nm,minimum at 280 nm.The metal analyses reveal only traces of zine and copper in addition to cadmium. The molecular weight is determined to be about 10 000 by gel filtration on HPLC and SDS-PAGE method. The isoelectric point of fish MT is demonstrated to be about 5.6.
Abstract:Pulsed-field gel electrophoresis and alkaline pulsed-field gel electrophoresis were used to analyze the chromosome DNAs of Ashbya gossypii and two kinds of its mutant strains CMG and JMG,which were obtained by γ-ray and Helium-Neon laser irradiation,respectively.The experiments resulted in the conclusions that AG contains five chromosome DNAs;and that no double-stranded breaks or loss of large DNA fragments but alkaline labile sites existed in both the mutant strains.
Abstract:The uptake and the retention of hypocrellin B(HB)by murine ascitic hepatoma(AH)cells was measured as function of incubation time.The data of uptake fitted the Freundlich adsorption isotherm very well over a wide range of hypocrellin B concentrations.The uptake occured very quickly and reached the maximun in 3 min at 37℃.The adsorped HB was quite difficult to be released to phosphate buffered solution whereas the releasing process was enhanced significantly by the addition of serum into the bath medium.The fluorescence quenching experiments using fatty acid probes located at different depths of cellular membranes indicated that the HB molecules have the trend inserting into the deep hydrophobic domains.
