Demographic vital rates and population growth: rethinking the relationship in a harvested elk population

Understanding the nature of the relationship between demographic vital rates and the rate of population change (λ) is important for determining effective strategies for population management and conservation. We examined the relative impacts of various demographic vital rates on λ within the range of temporal vital rate variability observed in a harvested population to test the hypotheses that adult survival rates in ungulates are relatively invariant when compared to other vital rates and that variability in calf survival has a greater influence on rates of population change than adult survival. Vital rates were estimated for an elk (_Cervus elaphus_) population at Fort Riley, Kansas from October 2003 – February 2007. The magnitude of adult survival rates were similar to other harvested populations and models including a negative relationship between survival and age received the highest levels of support. Prime-age adult survival had the highest stage-specific elasticity values, indicating a high contribution of these matrix elements to λ. Life-stage simulation analysis indicated that variation in calf survival had the highest correlation with variation in λ (r^2^ = 0.61). Our results suggest that adult survival rates in harvested populations may experience increased levels of variability, but that calf survival rates have the greatest relative influence on λ due to the wider range of variability observed for this vital rate

Molecular characterisation of four double-flowered mutants of Silene dioica representing four centuries of variation

Records of double-flowered Silene dioica date from the late sixteenth century and four named varieties are grown today, as previously, for their horticultural interest. Although double-flowered mutants have been characterized in several plants, their study in dioecious species is of particular interest due to influences of the homeotic mutation on the different floral whorl configurations in males and females. We have analysed four double-flowered varieties of Silene dioica: Flore Pleno and Rosea Plena date back to the seventeenth and nineteenth centuries, Thelma Kay and Firefly were recognized in the latter part of the twentieth and early twenty-first centuries. We have analysed the floral structure of the four varieties, which have distinct floral architectures. Based on Y chromosome-specific PCR analysis we show that Firefly is male and that the other three varieties are female: Random Amplification of Polymorphic DNA (RAPD) analyses suggested a common origin for the three female varieties. The double-flowered phenotype in all four varieties is caused by mutation of the C-function MADS-box transcription factor gene SDM1. We show that Firefly carries a unique 44bp insertion into SDM1, revealing an independent origin for this variety. Comparative analysis of SDM1 cDNA and genomic sequences in Flore Pleno, Rosea Plena and Thelma Kay shows that all three are caused by the same 7bp insertion within SDM1 and therefore share a common origin. The three alleles also differ by several single nucleotide polymorphisms, which represent somatic mutations accumulated over four centuries of asexual propagation

Regulated bioluminescence as a tool for bioremediation process monitoring and control of bacterial cultures

An effective on-line monitoring technique for toxic waste bioremediation using bioluminescent microorganisms has shown great potential for the description and optimization of biological processes. The lux genes of the bacterium Vibrio fischeri are used by this species to produce visible light. The lux genes can be genetically fused to the control region of a catabolic gene, with the result that bioluminescence is produced whenever the catabolic gene is induced. Thus the detection of light from a sample indicates that genetic expression from a specific gene is occurring. This technique was used to monitor biodegradation of specific contaminants from waste sites. For these studies, fusions between the lux genes and the operons for naphthalene and toluene/xylene degradation were constructed. Strains carrying one of these fusions respond sensitively and specifically to target substrates. Bioluminescence from these cultures can be rapidly measured in a nondestructive and noninvasive manner. The potential for this technique in this and other biological systems is discussed