A preliminary study of the nutritional requirements of Myxotrichum uncinatum
Certain nutritional requirements of one strain ofMyxotrichum uncinatum were established. Growth was measured on a dry weight basis. The approximate optimum medium for growth consisted of 5% KNO3, 4% sucrose, 0.1% K2HPO4, 0.05% MgSO4. 7 H2O, 0.2 mg % biotin and 1.0 mg % uracil. The best initial pH range was 6.0–7.0. Approximately three to five days incubation on a rotary shaker permitted excellent growth.
Growth and nutrition of a strain of Gymnoascus reessii in shaken flasks
The fundamental nutritional requirements of one strain ofGymnoascus reessii were established. Growth was measured on a dry weight basis. The optimum medium for growth consisted of 5% maltose, 2% KNO3, 0.2% K2HPO4, 0.2% MgSO4.7H2O, 1 mg% adenine, 1 mg% uracil, 1 mg% guanine, 5 mg% xanthine, 0.8 mg% biotin and 0.2 mg% pyridoxine. An initial Ph range of 5.0–8.0 was found to permit optimum growth. Die Grunderfordernisse der Ernährung eines Stammes vonGymnoascus reessii sind festgestellt worden. Das Wachstum war an der trockenen Gewichtsgrundlage gemessen. Der optimale Nährboden für das Wachstum bestand in 5% Maltose, 2% KNO3, 0.2% K2HPO4, 0.2% MgSO4. 7HO2, 1 mg% Adenine, 1 mg% Uracil, 1 mg% Guanine, 5 mg% Xanthine, 0.8 mg% Biotin und 0.2 mg% Pyridoxine. Eine Anfangsbreite der Ph von 5.0–8.0 erlaubte ein optimales Wachstum.
Electrophysiological Studies of Penticainide (CM 7857), a New Antiarrhythmic Agent, in Mammalian Myocardium
The intracellular electrophysiologic properties of a new antiarrhythmic substance, penticainide, were studied in isolated rabbit, dog, and guinea pig myocardial preparations superfused or perfused with oxygenated Tyrode's solution. “Therapeutic” concentrations of penticainide (1.5 to 3 x 10-5 M) had little effect on sinus node automaticity; sinoatrial conduction was slightly delayed. In atrial, Purkinje and ventricular fibers, amplitude, and maximal rate of rise of phase 0 (dV/dtmax) were decreased by penticainide; Purkinje-ventricle conduction velocity was depressed. Penticainide did not significantly modify action potential duration (APD) of rabbit atria and dog ventricle and reduced APD and effective refractory period (ERP) of dog Purkinje and guinea pig ventricular fibers. Penticainide reduced APD heterogeneity of Purkinje-ventricle junction with a preferential effect at the gate and decreased tension amplitude of perfused papillary muscle in dog heart. The effect of penticainide on dV/dtmax was voltage and rate dependent; the resting block was weak. Thus, penticainide is a class 1 antiarrhythmic agent with properties of class 1B agents such as APD reduction and properties of class 1C agents such as slow recovery kinetic of rate-dependent block.