Mixtures of Two Bile Alcohol Sulfates Function as a Proximity Pheromone in Sea Lamprey

Unique mixtures of pheromone components are commonly identified in insects, and have been shown to increase attractiveness towards conspecifics when reconstructed at the natural ratio released by the signaler. In previous field studies of pheromones that attract female sea lamprey (Petromyzon marinus, L.), putative components of the male-released mating pheromone included the newly described bile alcohol 3,12-diketo-4,6-petromyzonene-24-sulfate (DkPES) and the well characterized 3-keto petromyzonol sulfate (3kPZS). Here, we show chemical evidence that unequivocally confirms the elucidated structure of DkPES, electrophysiological evidence that each component is independently detected by the olfactory epithelium, and behavioral evidence that mature female sea lamprey prefer artificial nests activated with a mixture that reconstructs the male-released component ratio of 30:1 (3kPZS:DkPES, molar:molar). In addition, we characterize search behavior (sinuosity of swim paths) of females approaching ratio treatment sources. These results suggest unique pheromone ratios may underlie reproductive isolating mechanisms in vertebrates, as well as provide utility in pheromone-integrated control of invasive sea lamprey in the Great Lakes.     

Concurrent measurement of (Na+,K+)-ATPase activity and lipid peroxides in rat brain following reversible global ischemia

Lipid peroxides, quantitated as lipid conjugated dienes, and (Na⁺,K⁺)-ATPase activity were assayed concurrently in brains of control rats and in three groups subjected to 30 min of reversible forebrain ischemia followed by 0, 1, and 4 hr of recirculation. Multiple small samples were taken from lateral, dorsolateral and medial cortex, hippocampus, thalamus and striatum following in situ freezing. (Na⁺,K⁺)-ATPase activity was elevated in hippocampus, dorsolateral and lateral cortex (P<0.10) and in thalamus (P<0.05) following 30 min ischemia. ATPase activity in medial cortex continued to increase during the first 1 hr of recirculation (P<0.10). Following 4 hr of recirculation, decreased enzyme activities were observed in all of these regions (lateral cortex and hippocampus,P<0.10). No changes in ATPase activity were observed in samples from striatum. Of the regional samples assayed for lipid peroxide content, the incidence of conjugated dienes as a function of recirculation time was 6% (0 hr), 23% (1 hr), and 17% (4 hr). For these samples, plots of normalized ATPase activity vs. tissue conjugated diene concentration revealed that normalized ATPase activity varied with recirculation time, but was independent of the magnitude of the lipid peroxidative process (expressed in terms of tissue conjugated diene concentration). These results suggest that disturbances in membrane structure and function presumed to arise from lipid peroxidation are not responsible for the behavior of the ATPase under the current in vivo conditions.