The effects of ten cations and fifteen anions on the excitability of the squid giant axon were studied. The method of intracellular perfusion used in these investigations is described in detail. Empirical criteria were established for evaluating the relative favorability of any salt solution for maintaining the normal excitability of the membrane of the axon. It was found that both cations and ...

Evidence is presented that a brain fraction containing synaptosomal membrane fragments and ghosts prepared from lysed rat forebrain synaptosomes synthesize protein in a cell free system. The protein synthesis was dependent upon the addition of a synaptosomal membrane fraction, Mg++, monovalent cations, ATP, GTP, and enzyme factors prepared from intact synaptosomes. Protein synthesis was inhibit...

Short-term absorption studies with 5-day-old excised barley roots revealed that the basic aspects of Mn absorption were similar to those of other metabolically absorbed cations. Following an initial non-metabolic equilibration with the root, Mn was absorbed for several hours at a slower steady-state rate comparable to that of other inorganic cations. Complete or nearly complete inhibition of th...

Pichinde virus, a member of the arenavirus group, was examined for polymerase activity. Purified virus was found to contain RNA-dependent RNA polymerase but not RNA-dependent DNA polymerase activity. Since RNase but neither DNase nor actinomycin D inhibited the endogenous polymerase reaction, RNA of the virus appeared to be used as the template. The divalent cations Mg(2+) and Mn(2+) were requi...

A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the...

The divalent cations Ca2+, Mg2+, Co2+, Mn2+, Sr2+, and Ba2+ were compared for their stimulatory or inhibitory effect on PG formation in rabbit kidney medulla slices. Calcium, manganese, and strontium ions stimulated PG generation up to 3- to 5-fold in a time- and dose-dependent manner (Ca2+ greater than Mn2+ approximately Sr2+) while the magnesium and cobalt ions were without significant effect...