Many insects at rest breathe discontinuously, alternating between brief bouts of gas exchange and extended periods of breath-holding. The association between discontinuous gas exchange cycles (DGCs) and inactivity has long been recognised, leading to speculation that DGCs lie at one end of a continuum of gas exchange patterns, from continuous to discontinuous, linked to metabolic rate (MR). How...

1. Treatment of crude concentrates of streptokinase with protamine results in removal of about 90 per cent of the nitrogenous material, including nucleic acid and protease inhibitor, with little or no loss of activity. 2. Streptokinase solutions undergo reversible inactivation with changes in pH. The rate and extent of inactivation are dependent on pH, being greatest over a very narrow range ab...

Threonine deaminase from Rhodospirillum rubrum is subject to reversible cold inactivation a t low protein concentrations. The inactivation appears to involve a dissociation of the native tetrameric protein to dimers. The standard free energy of dissociation a t 0 "C was + 7.8 kcal/mole, while A H was 3.2 kcal/mole and AX was 41 entropy units. These values suggest that hydrophobic interactions a...

Microsaccades aid vision by helping to strategically sample visual scenes. Despite the importance of these small eye movements, no cortical area has ever been implicated in their generation. Here, we used unilateral and bilateral reversible inactivation of the frontal eye fields (FEF) to identify a cortical drive for microsaccades. Unexpectedly, FEF inactivation altered microsaccade metrics and...