PURIFICATION AND PROPERTIES OF SERINE HYDROXYMETHYLTRANSFERASE FROM NICOTIANA RUSTICA L.

Serine hydroxymethyltransferase was partially purified fromNicotiana rustica roots. The pH optimum for the enzyme is 4.0.A requirement for pyridoxal phosphate and a divalent cationwas shown, and the enzyme was inhibited by sulfhydryl reagentsand the reaction is folic acid-dependent. ¹Contribution from the Department of Biochemistry and publishedwith the approval of the Director of Research as Paper No. 2175in the Journal Series ²Present address; Spruance Research Laboratories, E. I. du Pontde Nemours and Company, Inc., Post Office Box 1477, Richmond,Virginia 23212, U.S.A.     

The relative lability of floral vs. non-floral characters and a morphological phylogenetic analysis of Cobaea (Polemoniaceae)

The relative levels of lability in floral vs. vegetative characters have been suggested to give insight into the mechanisms of adaptation and speciation. Cobaea (Polemoniaceae) exhibits a remarkable diversity in floral form. A morphology-based phylogeny was constructed and is congruent in most regards with a previously published molecular phylogeny, but significant incongruence was found in the placement of two taxa. A combined analysis was performed, excluding C. aquatoriensis and C. lutea, and was nearly identical to the molecular analysis. The phylogenies are compatible with a recently published classification. Incongruencies between the phylogenies within section Rosenbergia may have profound implications for floral evolution. A simple method for testing the levels of homoplasy, as an indicator of lability between two classes of data, is developed and used to test for differences between floral and non-floral classes of characters. The method is based on repeated randomization of the data into partitions and recalculation of a test statistic defined as the difference between consistency index (CI) values of the data in each partition over a given tree. The null hypothesis that the floral characters are no more homoplasious than the non-floral characters cannot be rejected (P=0.09).     

Raptor and Corvid Response to Power Distribution Line Perch Deterrents in Utah

Abstract: Increased raptor and corvid abundance has been documented in landscapes fragmented by man-made structures, such as fence posts and power lines. These vertical structures may enhance raptor and corvid foraging and predation efficiency because of increased availability of perch, nesting, and roosting sites. Concomitantly, vertical structures, in particular power distribution lines, have been identified as a threat to sage-grouse (Centrocercus spp.) conservation. To mitigate potential impacts of power distribution lines on sage-grouse and other avian species, the electrical power industry has retrofitted support poles with perch deterrents to discourage raptor and corvid use. No published information is available regarding efficacy of contemporary perch deterrents on avian predator use of lower-voltage power distribution lines. We evaluated efficacy of 5 perch deterrents mounted on support poles of an 11-km section of a 12.5-kV distribution line that bisected occupied Gunnison sage-grouse (Centrocercus minimus) habitat in southeastern Utah, USA. Perch deterrents were mounted on the line in November–December 2006 following a random replicated block design that included controls. During 168 hours and 84 hours of direct observation in 2007 and 2008, respectively, we recorded 276 and 139 perching events of 7 potential avian predators of sage-grouse. Golden eagles (Aquila chrysaetos) were the dominant species we recorded during both years. We did not detect any difference in perching events by perch deterrent we evaluated and controls (P > 0.05). Perch deterrents we evaluated were not effective because of inherent design and placement flaws. Additionally, previous pole modifications that mitigated avian electrocutions provided alternative perches. We did not record any raptor or corvid electrocutions or direct predation on Gunnison sage-grouse. The conclusions of this study can be applied by conservation groups and power companies to future management of power distribution lines within areas inhabited by species sensitive to man-made vertical structures.