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Distinct Contributions Of Model Masp1 And Masp2 Like Peptides To The Mechanical Properties Of Synthetic Major Ampullate Silk Fibers As Revealed In Silico, Amanda E. Brooks, Shane R. Nelson, Justin A. Jones, Courtney Koenig, Michael Hinman, Michael Hinman, Shane Stricker, Randolph V. Lewis
Distinct Contributions Of Model Masp1 And Masp2 Like Peptides To The Mechanical Properties Of Synthetic Major Ampullate Silk Fibers As Revealed In Silico, Amanda E. Brooks, Shane R. Nelson, Justin A. Jones, Courtney Koenig, Michael Hinman, Michael Hinman, Shane Stricker, Randolph V. Lewis
Biology Faculty Publications
All characterized major ampullate silks from orb-web weaving spiders are composites of primarily two different proteins: MaSp1 and MaSp2. The conserved association of MaSp1 and MaSp2 in these spider species, the highly conserved amino acid motifs, and variable ratios of MaSp1 to MaSp2 demonstrate the importance of both MaSp1 and MaSp2 to the strength and elasticity of the fiber. Computer simulated mechanical tests predicted differing roles for MaSp1 and MaSp2 in the mechanical properties of the fibers. Recombinant MaSp1 and MaSp2 proteins were blended and spun into fibers mimicking the computer-simulated conditions. Mechanical testing verified the differing roles of MaSp1 …
Are Rivers Just Bigstreams? Using A Pulse Method To Measure Nitrogen Demand In A Large River, J. L. Tank, E. J. Rosi-Marshall, Michelle A. Baker, R. O. Hall Jr.
Are Rivers Just Bigstreams? Using A Pulse Method To Measure Nitrogen Demand In A Large River, J. L. Tank, E. J. Rosi-Marshall, Michelle A. Baker, R. O. Hall Jr.
Biology Faculty Publications
Given recent focus on large rivers as conduits for excess nutrients to coastal zones, their role in processing and retaining nutrients has been overlooked and understudied. Empirical measurements of nutrient uptake in large rivers are lacking, despite a substantial body of knowledge on nutrient transport and removal in smaller streams. Researchers interested in nutrient transport by rivers (discharge >10000 L/s) are left to extrapolate riverine nutrient demand using a modeling framework or a mass balance approach. To begin to fill this knowledge gap, we present data using a pulse method to measure inorganic nitrogen. (N) transport and removal in the …
Chihuahuan Desertkangaroo Rats: Nonlinear Effects Of Population Dynamics, Competition, And Rainfall, M. Lima, S.K. Morgan Ernest, J. H. Brown, A. Belgrano, N. C. Stenseth
Chihuahuan Desertkangaroo Rats: Nonlinear Effects Of Population Dynamics, Competition, And Rainfall, M. Lima, S.K. Morgan Ernest, J. H. Brown, A. Belgrano, N. C. Stenseth
Biology Faculty Publications
Using long-term data on two kangaroo rats in the Chihuahuan Desert of North America, we fitted logistic models including the exogenous effects of seasonal rainfall patterns. Our aim was to test the effects of intraspecific interactions and seasonal rainfall in explaining and predicting the numerical fluctuations of these two kangaroo rats. We found that logistic models fit both data sets quite well; Dipodomys merriami showed lower maximum per capita growth rates than Dipodomys ordii, and in both cases logistic models were nonlinear. Summer rainfall appears to be the most important exogenous effect for both rodent populations; models including this variable …
On Estimating The Exponent Of Power-Law Frequency Distributions, Ethan P. White, B. J. Enquist, J. L. Green
On Estimating The Exponent Of Power-Law Frequency Distributions, Ethan P. White, B. J. Enquist, J. L. Green
Biology Faculty Publications
Power-law frequency distributions characterize a wide array of natural phenomena. In ecology, biology, and many physical and social sciences, the exponents of these power-laws are estimated to draw inference about the processes underlying the phenomenon, to test theoretical models, and to scale up from local observations to global patterns. Therefore, it is essential that these exponents be estimated accurately. Unfortunately, the binning-based methods traditionally utilized in ecology and other disciplines perform quite poorly. Here we discuss more sophisticated methods for fitting these exponents based on cumulative distribution functions and maximum likelihood estimation. We illustrate their superior performance at estimating known …
On The Relationship Between Mass And Diameter Distributions In Tree Communities, J. C. Stegen, Ethan P. White
On The Relationship Between Mass And Diameter Distributions In Tree Communities, J. C. Stegen, Ethan P. White
Biology Faculty Publications
It has been suggested that frequency distributions of individual tree masses in natural stands are characterized by power-law distributions with exponents near -3/4, and that therefore tree communities exhibit energetic equivalence among size classes. Because the mass of trees is not measured directly, but estimated from diameter, this supposition is based on the fact that the observed distribution of tree diameters is approximately characterized by a power-law with an exponent -2. Here we show that diameter distributions of this form are not equivalent to mass distributions with exponents of -3/4, but actually to mass distributions with exponents of -11/8. We …
Zero-Sum, The Niche,And Metacommunities: Long-Term Dynamics Of Community Assembly, S.K. Morgan Ernest, J. H. Brown, K. M. Thibault, Ethan P. White, J. R. Goheen
Zero-Sum, The Niche,And Metacommunities: Long-Term Dynamics Of Community Assembly, S.K. Morgan Ernest, J. H. Brown, K. M. Thibault, Ethan P. White, J. R. Goheen
Biology Faculty Publications
Recent models of community assembly, structure, and dynamics have incorporated, to varying degrees, three mechanistic processes: resource limitation and interspecific competition, niche requirements of species, and exchanges between a local community and a regional species pool. Synthesizing 30 years of data from an intensively studied desert rodent community, we show that all of these processes, separately and in combination, have influenced the structural organization of this community and affected its dynamical response to both natural environmental changes and experimental perturbations. In addition, our analyses suggest that zero-sum constraints, niche differences, and metacommunity processes are inextricably linked in the ways that …
Strong Genetic Differentiation Among Neighboring Populations Of A Locally Endemic Primrose, L. Bjerregaard, Paul G. Wolf
Strong Genetic Differentiation Among Neighboring Populations Of A Locally Endemic Primrose, L. Bjerregaard, Paul G. Wolf
Biology Faculty Publications
Maguire primrose is a locally endemic plant of northern Utah, USA, with a total known range of less than 20 km2. A previous study found evidence for strong differentiation among local populations at 4 allozyme loci. Here we reexamined populations using 165 AFLP loci and found further evidence of unusually strong genetic structure. We also found an apparently fixed nucleotide difference between populations for a noncoding region of chloroplast DNA, mirroring the patterns seen for AFLP loci. Furthermore, we tested the hypothesis that the current population structure is the result of breeding barriers between plants from different populations. We made …
Functional Gene Losses Occur With Minimal Size Reduction In The Plastid Genome Of The Parasitic Liverwort Aneura Mirabilis, N. J. Wickett, Y. Zhang, S. K. Hansen, J. M. Roper, J. V. Kuehl, S. A. Plock, B. Goffinet, Paul G. Wolf, C. W. Depamphilis, Jeffrey L. Boore
Functional Gene Losses Occur With Minimal Size Reduction In The Plastid Genome Of The Parasitic Liverwort Aneura Mirabilis, N. J. Wickett, Y. Zhang, S. K. Hansen, J. M. Roper, J. V. Kuehl, S. A. Plock, B. Goffinet, Paul G. Wolf, C. W. Depamphilis, Jeffrey L. Boore
Biology Faculty Publications
Aneura mirabilis is a parasitic liverwort that exploits an existing mycorrhizal association between a basidiomycete and a host tree. This unusual liverwort is the only known parasitic seedless land plant with a completely nonphotosynthetic life history. The complete plastid genome of A. mirabilis was sequenced to examine the effect of its nonphotosynthetic life history on plastid genome content. Using a partial genomic fosmid library approach, the genome was sequenced and shown to be 108,007 bp with a structure typical of green plant plastids. Comparisons were made with the plastid genome of Marchantia polymorpha, the only other liverwort plastid sequence available. …
Conservation Of Selection On Matk In Ferns Following An Ancient Loss Its Flanking Intron, A. M. Duffy, S. A. Kelchner, Paul G. Wolf
Conservation Of Selection On Matk In Ferns Following An Ancient Loss Its Flanking Intron, A. M. Duffy, S. A. Kelchner, Paul G. Wolf
Biology Faculty Publications
The chloroplast gene trnK and its associated group II intron appear to be absent in a large and ancient clade that includes nearly 90% of fern species. However, the maturase protein encoded within the intron (matK) is still present and located on the boundary of a large-scale inversion. We surveyed the chloroplast genome sequence of clade-member Adiantum capillus-veneris for evidence of a still present but fragmented trnK intron. Lack of signature structural domains and sequence motifs in the genome indicate loss of the trnK intron through degradation in an ancestor of the clade. In plants, matK preferentially catalyzes splicing of …