Enzymic reduction of free fatty aldehydes in bovine cardiac muscle

The reduction of fatty aldehydes to fatty alcohols by a soluble enzyme in bovine cardiac muscle has been demonstrated. The enzymic activity is precipitable between 38–95% saturation with ammonium sulfate. NADPH is the required cofactor for this reduction. The reaction is irreversible under the conditions employed in this assay.     

Cyclic modes in neural net models

Neural network models with possible cross-coupling from every neuron to every other neuron are condisered. The all-or-none law is assumed for firing of neurons. A network is shown to have a set of latent cyclic modes. If the net is stimulated briefly, it will subsequently either return to quiescence or settle into periodic activity in one of its cyclic modes. Realization of cyclic modes and analysis of nets are discussed. A learning rule for adjustment of synaptic strengths is presented.     

An electron microscope study of the influence of divalent ions on myosin filament formation in chicken gizzard extracts and homogenates

Myosin as well as actin filaments could be seen in negatively stained preparations of fresh chicken gizzard homogenized in buffered KCI (I=0-12, pH 6.85), in a 1 : 1 ratio. Myosin filaments were also present when homogenates were diluted (1 : 9) with solutions containing additional Mg(++) and ATP provided naturally occurring traces of Ca(++) had not been chelated with EGTA. There were no myosin filaments when Mg(++), ATP, Ca(++) or Ca(++) + ATP were added respectively to the diluent. It is suggested that in vivo in relaxed muscles myosin is present in dimers, and only aggregates into filaments at the onset of contraction when Ca(++) are released.