Dissimilar responses of membrane potential (EM), permeability properties and respiration to cadmium and nickel in maize root cells

The short-term treatment with Cd2+ and Ni2+ triggered transient depolarization of transplasma membrane potential (EM) in the outer cortical root cells of two maize cultivars (cv. Premia and cv. Blitz), however, both metals changed the EM in a quantitatively different way. The magnitude and duration of EM depolarization were concentration dependent and were greater in the metal susceptible cv. Blitz. The highest EM depolarization was recorded with simultaneous application of Cd2+ + Ni2+ in both maize cultivars. The EM depolarization induced by Cd2+ or Cd2+ + Ni2+ but not Ni2+ alone was accompanied with a tremendous increase of membrane conductivity, but it was not accompanied with the effect of heavy metals (HM) on respiration. Simultaneous application of fusiccocin (FC) with Cd2+ or Cd2+ + Ni2+ during the EM depolarization, inability of FC to stop the depolarization by FC-enhanced proton extrusion and rapid restoration of EM, suggested a transient inhibition of the plasma membrane H+-ATPase by these toxic metals. Our data support the opinion that differences in the effects of the studied ions were not the result of their direct action on PM, but rather of their different influence on intracellular processes within root cells

Sexual communication in the termite Prorhinotermes simplex (Isoptera, Rhinotermitidae) mediated by a pheromone from female tergal glands

We studied the post-flight behavior and sex attraction in imagoes of the termite Prorhinotermes simplex (Rhinotermitidae, Prorhinotermitinae). Pairing is mediated by the secretion from tergal glands, exposed by females in a calling posture and highly attractive to males. Analysis of extracts of these glands by means of gas chromatography with electroantennographic detection indicated a chromatographic area corresponding to an intense physiological response of males. The retention characteristics of this area proved to be identical with those of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Electroantennographic and behavioral assays revealed that units of picograms of the compound represent a stimulus qualitatively and quantitatively equivalent to one female tergal gland. Thus, we hypothesize that (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol is a major component of the female sex pheromone in P. simplex. © 2009 Birkhäuser Verlag, Basel/Switzerland.SCOPUS: ar.jinfo:eu-repo/semantics/publishe