Elimination of interferences in the colorimetric analysis of ammonium in water and soil extracts

Willis, Raymond B.; Schwab, G. J.; Gentry, Claude E.

doi:10.1080/00103629309368857

Cited by 24 publications

(16 citation statements)

References 13 publications

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“…Residual ammonium was determined by a modified version of the Berthelot reaction [87], scaled down for 96-well format. Biomass was estimated by filtering 50 mL of chemostat culture onto tared 0.45 µm nylon filters, and drying filters in a desiccator at 37°C for 48 hrs.…”

Section: Methodsmentioning

confidence: 99%

Recurrent Rearrangement during Adaptive Evolution in an Interspecific Yeast Hybrid Suggests a Model for Rapid Introgression

et al. 2013

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Genome rearrangements are associated with eukaryotic evolutionary processes ranging from tumorigenesis to speciation. Rearrangements are especially common following interspecific hybridization, and some of these could be expected to have strong selective value. To test this expectation we created de novo interspecific yeast hybrids between two diverged but largely syntenic Saccharomyces species, S. cerevisiae and S. uvarum, then experimentally evolved them under continuous ammonium limitation. We discovered that a characteristic interspecific genome rearrangement arose multiple times in independently evolved populations. We uncovered nine different breakpoints, all occurring in a narrow ∼1-kb region of chromosome 14, and all producing an “interspecific fusion junction” within the MEP2 gene coding sequence, such that the 5′ portion derives from S. cerevisiae and the 3′ portion derives from S. uvarum. In most cases the rearrangements altered both chromosomes, resulting in what can be considered to be an introgression of a several-kb region of S. uvarum into an otherwise intact S. cerevisiae chromosome 14, while the homeologous S. uvarum chromosome 14 experienced an interspecific reciprocal translocation at the same breakpoint within MEP2, yielding a chimaeric chromosome; these events result in the presence in the cell of two MEP2 fusion genes having identical breakpoints. Given that MEP2 encodes for a high-affinity ammonium permease, that MEP2 fusion genes arise repeatedly under ammonium-limitation, and that three independent evolved isolates carrying MEP2 fusion genes are each more fit than their common ancestor, the novel MEP2 fusion genes are very likely adaptive under ammonium limitation. Our results suggest that, when homoploid hybrids form, the admixture of two genomes enables swift and otherwise unavailable evolutionary innovations. Furthermore, the architecture of the MEP2 rearrangement suggests a model for rapid introgression, a phenomenon seen in numerous eukaryotic phyla, that does not require repeated backcrossing to one of the parental species.

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Section: Methodsmentioning

confidence: 99%

Recurrent Rearrangement during Adaptive Evolution in an Interspecific Yeast Hybrid Suggests a Model for Rapid Introgression

et al. 2013

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“…Extractable NH 4 + and NO 3 -were extracted by shaking 25 g (dry weight equivalent) of soil in 50 ml of 2 M KCl followed by filtration through Whatman #42 filter paper. Extracts were analyzed on a segmented flow analyzer (Auto Analyzer III, Bran Luebbe, Chicago, IL) using the Berthelot reaction (Willis et al, 1993) and cadmium reduction method (Willis and Gentry, 1987), respectively. Amino N was measured on these same extracts using the ninhydrin method (Moore, 1968) and polyphenols by the Prussian Blue method (Stern et al, 1996).…”

Section: Laboratory Methodsmentioning

confidence: 99%

Restoration treatments in a Montana ponderosa pine forest: Effects on soil physical, chemical and biological properties

Gundale

DeLuca

Fiedler

et al. 2005

Forest Ecology and Management

118

142

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“…Soils were incubated for 14 days at 25 8C, upon which samples were extracted in 2 M KCl. Amino N, NH 4 + , and NO 3 À were measured from these extracts using the ninhydrin method (Moore, 1968), the Berthelot reaction (Willis et al, 1993) and the cadmium reduction method (Willis and Gentry, 1987), respectively.…”

Section: Nitrogen Mineralization and Nitrificationmentioning

confidence: 99%

Temperature and source material influence ecological attributes of ponderosa pine and Douglas-fir charcoal

Gundale

DeLuca

2006

Forest Ecology and Management

249

134

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Elimination of interferences in the colorimetric analysis of ammonium in water and soil extracts

Cited by 24 publications

References 13 publications

Recurrent Rearrangement during Adaptive Evolution in an Interspecific Yeast Hybrid Suggests a Model for Rapid Introgression

Recurrent Rearrangement during Adaptive Evolution in an Interspecific Yeast Hybrid Suggests a Model for Rapid Introgression

Restoration treatments in a Montana ponderosa pine forest: Effects on soil physical, chemical and biological properties

Temperature and source material influence ecological attributes of ponderosa pine and Douglas-fir charcoal

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