Tests of sib diversification theories of outcrossing in Impatiens capensis: Effects of inbreeding and neighbour relatedness on production and infestation

Several models of the evolution of genetic systems posit very strong frequency-dependent selection acting on small spatial scales; in such circumstances a genetically diverse sibship outperforms a genetically uniform sibship, and genes for mixis may spread in a population. Such selection regimes may derive from resource limitation and/or parasite transmission. We describe a greenhouse experiment designed to test these ideas, using the annual herb Impatiens capensis. Plants were potted in pairs; the genetic variance within pots was manipulated by using progeny from either inbred or outcrossed parents and by using either full sibs or unrelated individuals. Treatment combinations designed to increase genetic diversity resulted in greater phenotypic variance in both morphology and production, though not in the density of spider mites or whiteflies. Despite evidence of resource limitation, there was no effect of genetic diversity on productivity, nor was there an effect on infestation. These results fail to support either the sib competition or the sib contagion theory of outcrossing.     

Phosphorus and fluorine NMR examination of the anesthetized newt (Notopthalamus viridescens)

We have examined newts by 19F-NMR using the anesthetic halothane as a probe and in another set of experiments taken 31P-NMR spectra under similar conditions. The spectra were recorded from the animal's tail. The water soluble 31P-NMR signals point to little difference between anesthetized and unanesthetized newts except for the potential disappearance of two pools of inorganic phosphate in the anesthetized animals. The 19F spectra show two anesthetic populations in the tail which the phosphorus spectra suggest arise from populations of halothane in muscle and in lipid.     

NMR spectroscopy as an investigative technique in physiology

Relating physiological variables on an organ system level to metabolic function within the intracellular environment has been exceedingly difficult because of a paucity of techniques. Most of the tools at our command necessitate either the removal or destruction of tissues before measurements can be made. Recently, NMR spectroscopy has been applied to several important questions relating organ system and cellular physiology. NMR has the distinct advantage of being noninvasive and nondestructive, allowing the investigator to make repetitive measurements of intracellular variables while manipulating experimental variables that are important on the organ system level. In this review we shall present several examples of such NMR investigations so that the reader will gain some appreciation of the potential of this relatively new technique. Cellular acid-base homeostatic mechanisms, high-energy phosphate metabolism, and regulation of anaerobic glycolysis will be discussed for such diverse cellular populations as mammalian brain, mammalian heart muscle, salamander skeletal muscle, amphibian skin, and invertebrate muscle. In addition, the role of phosphomonoesters and phosphodiesters in lipid metabolism for several tissues in different species will be evaluated.     

Is fluidization of the phospholipid bilayer by general anesthetics a reason for general anesthesia?]

It was found that chlorpromazine and pipolfene potentiating general anaesthesia increase viscosity of phospholipid membrane in the region of polar headgroups and in the hydrophobic area near glycerol sceleton. These results (independently of potentiating mechanism) confuse a mechanism of anaesthetics action as increased fluidity of membrane phospholipids.