三元体系Mg2+//Cl-,borate-H2O在308.15K时稳定相平衡研究

采用等温溶解法研究了三元体系Mg2+//C1-,borate-H20在308.15 K时的稳定相平衡;测定了上述体系液相中各组份的平衡溶解度及物化性质(密度和pH),根据实验数据绘制了相应相图和物化性质组成图.该体系在308.15 K时有1个共饱点(水氯镁石+镁硼酸盐)、2条饱和溶解度曲线和2个结晶相区,无复盐及固溶体...     

含钙卤水体系相平衡研究进展

盐湖卤水资源的成功开发,需以相应的相平衡与相图研究成果为指导,开展含钙多组分卤水体系相平衡的研究,对于我国近年发现的含钙卤水资源的开发利用具有重要的意义。本文主要从含钙的海水体系、碳酸盐体系、硼酸盐体系和锂钙共存的卤水体系等方面,归纳总结了国内外关于含钙卤水体系的相平衡研究进展,探讨了研究中存在的一些问题,进一步指出了含钙卤水体系相平衡的研究方向。     

The Na+, K+, Ca2+, Mg2+ and Cl− composition of giant fibers fromBalanus nubilus

Zusammenfassung Es werden Analysenresultate über den Ionengehalt von einzelnen Muskelfasern der Entenmuschel,Balanus nubilus, mitgeteilt. Es wurden Unterschiede nachgewiesen in der Ionenkonzentration verschiedener Fasern, die von demselben Muskelbündel isoliert worden waren.     

Inhibition of sarcolemmal Na,K, Mg ATPase from the guinea pig heart is not compatible with a homogeneous population of non-interacting ouabain receptors

Summary The inhibition of sarcolemmal Na, K, Mg ATPase from the guinea pig heart by ouabain was evaluated with a coupled enzyme assay. Models of negative cooperativity and of two independent receptors fitted the inhibition data equally well. The analysis was not compatible with a homogeneous population of non-interacting ouabain receptors.Acknowledgments. The technical assistance of P. Mayr and G. Ruhland is gratefully acknowledged.     

Inhibition of sarcolemmal Na, K, Mg ATPase from the guinea pig heart is not compatible with a homogeneous population of non-interacting ouabain receptors

The inhibition of sarcolemmal Na, K, Mg ATPase from the guinea pig heart by ouabain was evaluated with a coupled enzyme assay. Models of negative cooperativity and of two independent receptors fitted the inhibition data equally well. The analysis was not compatible with a homogeneous population of non-interacting ouabain receptors.     

Demonstration of a Na+−K+−Mg2+ dependent ATPase in a preparation from hindgut and malpighian tubules of two species of insect

Zusammenfassung Die Präsenz einer charakteristischen Na⁺–K⁺-aktivierbaren ATPase (E.C. 3.6.1.3) wurde erstmals in einer mikrosomalen Fraktion des Enddarmes und der malpighischen Gefässe bei der WüstenschreckeScistocerca gregaria und der LaubheuschreckeJamaicana flava nachgewiesen.     

Temperature acclimation of Mg2+Ca2+-myofibrillar ATPase from a cold-selective teleost,Salvelinus fontinalis: a compromise solution

Summary Brook trout (Salvelinus fontinalis, Mitchill) were acclimated over 15 weeks to either +4°C or +24°C. The effects of temperature on myofibrillar Mg²⁺Ca²⁺-ATPase activities were investigated. In contrast to goldfish, temperature acclimation does not alter the kinetic properties of the brook trout myofibrillar ATPase. Activation energy (G^#) is lower and substrate turnover number is higher than values previously reported for cold-adapted stenotherms. Properties of brook trout ATPase appear to be a compromise enabling function across a broad temperature range. The different strategies of adapting to seasonal temperature variations are briefly discussed.The authors are grateful to the Wellcome Trust for financial support.-Correspondence should be addressed to I.A.J.     

Temperature acclimation of Mg2+Ca2+-myofibrillar ATPase from a cold-selective teleost, Salvelinus fontinalis: a compromise solution

Brook trout (Salvelinus fontinalis, Mitchill) were acclimated over 15 weeks to either +4 degrees C or +24 degrees C. The effects of temperature on myofibrillar Mg2+Ca2+-ATPase activities were investigated. In contrast to goldfish, temperature acclimation does not alter the kinetic properties of the brook trout myofibrillar ATPase. Activation energy (delta G not equal to) is lower and substrate turnover number is higher than values previously reported for cold-adapted stenotherms. Properties of brook trout ATPase appear to be a compromise enabling function across a broad temperature range. The different strategies of adapting to seasonal temperature variations are briefly discussed.