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Full-Text Articles in Life Sciences

How Anthocyanin Mutants Respond To Stress: The Need To Distinguish Between Stress Tolerance And Maximal Vigour, Eric J. Von Wettberg, Maureen L. Stanton, Justen B. Whittall May 2010

How Anthocyanin Mutants Respond To Stress: The Need To Distinguish Between Stress Tolerance And Maximal Vigour, Eric J. Von Wettberg, Maureen L. Stanton, Justen B. Whittall

Biology

Background: Anthocyanins are produced by plants in response to diverse stresses Mutants that block the anthocyanin biosynthetic pathway (A BP) at various steps can easily be compared across numerous abiotic stresses Hypothesis: Anthocyanins or their precursors are required for stress tolerance. Thus, ABP loss-of-function mutants should have proportionately lower fitness than wildtype plants under stress, compared with benign conditions In contrast, a decrease in maximal vigour the general capacity for growth and fecundity should be most pronounced under benign conditions that allow luxuriant growth by the most vigorous genotypes Tests: Determine whether, under stressful conditions. ABP loss-of-function mutants have relatively …


Influence Of Functionalized Fullerene Structure On Polymer Photovoltaic Degradation, Brian H. Johnson, Enaanake Allagoa, Robert L. Thomas, Gregory Stettler, Marianne Wallis, Justn H. Peel, Thorsteinn Adalsteinsson, Brian J. Mcnelis, Richard P. Barber Jr. Mar 2010

Influence Of Functionalized Fullerene Structure On Polymer Photovoltaic Degradation, Brian H. Johnson, Enaanake Allagoa, Robert L. Thomas, Gregory Stettler, Marianne Wallis, Justn H. Peel, Thorsteinn Adalsteinsson, Brian J. Mcnelis, Richard P. Barber Jr.

Physics

The time dependence of device performance has been measured for photocells using blends containing the conjugated polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) with two different functionalized C60 electron acceptor molecules: commercially available [6,6]-phenyl C61 butyric acid methyl ester (PCBM) or [6,6]-phenyl C61 butyric acid octadecyl ester (PCBOD) produced in this laboratory. Performance was characterized by the short-circuit current output of the devices, with the time dependence of PCBM samples typically degrading exponentially. Variations in the characteristic lifetime of the devices were observed to depend on the molar fraction of the electron acceptor molecules (calculated with respect to the MEH-PPV monomer fraction). In comparison …


Finding A (Pine) Needle In A Haystack: Chloroplast Genome Sequence Divergence In Rare And Widespread Pines, Justen B. Whittall, John Syring, Matthew Parks, Jason Buenrostro, Cynthia A. Dick, Aaron Liston, Richard Cronn Feb 2010

Finding A (Pine) Needle In A Haystack: Chloroplast Genome Sequence Divergence In Rare And Widespread Pines, Justen B. Whittall, John Syring, Matthew Parks, Jason Buenrostro, Cynthia A. Dick, Aaron Liston, Richard Cronn

Biology

Critical to conservation efforts and other investigations at low taxonomic levels, DNA sequence data offer important insights into the distinctiveness, biogeographic partitioning and evolutionary histories of species. The resolving power of DNA sequences is often limited by insufficient variability at the intraspecific level. This is particularly true of studies involving plant organelles, as the conservative mutation rate of chloroplasts and mitochondria makes it difficult to detect polymorphisms necessary to track genealogical relationships among individuals, populations and closely related taxa, through space and time. Massively parallel sequencing (MPS) makes it possible to acquire entire organelle genome sequences to identify cryptic variation …


Genetic Variation At Nuclear Loci Fails To Distinguish Two Morphologically Distinct Species Of Aquilegia, Elizabeth A. Cooper, Justen B. Whittall, Scott A. Hodges, Magnus Nordborg Jan 2010

Genetic Variation At Nuclear Loci Fails To Distinguish Two Morphologically Distinct Species Of Aquilegia, Elizabeth A. Cooper, Justen B. Whittall, Scott A. Hodges, Magnus Nordborg

Biology

Aquilegia formosa and pubescens are two closely related species belonging to the columbine genus. Despite their morphological and ecological differences, previous studies have revealed a large degree of intercompatibility, as well as little sequence divergence between these two taxa [1,2]. We compared the inter- and intraspecific patterns of variation for 9 nuclear loci, and found that the two species were practically indistinguishable at the level of DNA sequence polymorphism, indicating either very recent speciation or continued gene flow. As a comparison, we also analyzed variation at two loci across 30 other Aquilegia taxa; this revealed slightly more differentiation among taxa, …