Soybean isoflavones trigger a calcium influx in Phytophthora sojae.

Both the motile zoospores and the hyphal germ tubes of Phytophthora sojae respond chemotropically to the soybean isoflavones daidzein and genistein. The role of Ca(2+) in the cellular response to these host signals was investigated by using X-ray microanalysis of cells to monitor net changes in cellular levels of Ca(2+) and by quantifying the effects of exogenous Ca(2+) and daidzein on the developmental fate of encysted zoospores. Confirmation that isoflavones trigger a net influx of Ca(2+) into the cell was demonstrated by X-ray microanalysis of individual encysted zoospores. Zoospores exposed to 10 mM Ca(2+) and 1 microM daidzein at the time of encystment formed cysts that contained more Ca(2+) than zoospores exposed to Ca(2+) alone. The magnitude of internal Ca(2+) stores appears to be a determining factor affecting the developmental fate of P. sojae cysts.

Lighting cycle and social isolation affect development of elevated blood pressure in spontaneously hypertensive rats.

Around-the-clock blood pressure measurements repeated from the 2nd to 6th month of life in spontaneously hypertensive rats (SHR) quantify circadian rhythmicity during the development of an elevated mean blood pressure. The rise in overall pressure is aggravated by social isolation in SHR maintained on a 12-hour white light/12-hour dim red light cycle, but not in SHR kept in continuous dim red light. The demonstration of this interaction is not possible with blood pressure measurements performed only at certain (convenient) times: failure to quantify the circadian rhythm in systolic blood pressure leads to conclusions which can vary with the circadian time at which measurements are made, even in comparisons at the same fixed clock-hour. Thus, in order to model and optimize multiple factors interacting in the genesis of overall mammalian pressure in SHR, rhythmometry is an indispensable tool as it is in other fields.