Biology Commons^™

Patterns Of Genetic Divergence Across Geographically Variable Populations Of Xanthisma Gracile (Asteraceae), Lavanya Challagundla, Lisa E. Wallace

Biological Sciences Faculty Publications

Premise of research. Numerous biotic and abiotic factors can contribute to local selection and lead to geographic structure and genetic divergence between populations. The southwestern United States contains many distinctive plant communities, ranging from woodlands to desert scrub, that are shaped by species adapting to local variation in elevation, precipitation, seasonality, and soils. Given this variation, species occurring across diverse habitats are expected to harbor high genetic diversity and exhibit significant genetic differences associated with environmental variation.

Methodology. Here, we studied the genetic divergence of populations of Xanthisma gracile (Asteraceae) across Arizona using amplified fragment length polymorphisms and evaluated associations …

Electrostatically Localized Proton Bioenergetics: Better Understanding Membrane Potential, James Weifu Lee

Chemistry & Biochemistry Faculty Publications

In Mitchell's chemiosmotic theory, membrane potential Δψ was given as the electric potential difference across the membrane. However, its physical origin for membrane potential Δψ was not well explained. Using the Lee proton electrostatic localization model with a newly formulated equation for protonic motive force (pmf) that takes electrostatically localized protons into account, membrane potential has now been better understood as the voltage difference contributed by the localized surface charge density ([H-⁺_L] + ⁿΣ _i=1 [M⁽ⁱ⁺⁾_L]) at the liquid-membrane interface as in an electrostatically localized protons/cations-membrane-anions capacitor. That is, the origin of membrane …

Selective Distant Electrostimulation By Synchronized Bipolar Nanosecond Pulses, Elena C. Gianulis, Maura Casciola, Carol Zhou, Enbo Yang, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

A unique aspect of electrostimulation (ES) with nanosecond electric pulses (nsEP) is the inhibition of effects when the polarity is reversed. This bipolar cancellation feature makes bipolar nsEP less efficient at biostimulation than unipolar nsEP. We propose to minimize stimulation near pulse-delivering electrodes by applying bipolar nsEP, whereas the superposition of two phase-shifted bipolar nsEP from two independent sources yields a biologically-effective unipolar pulse remotely. This is accomplished by electrical compensation of all nsEP phases except the first one, resulting in the restoration of stimulation efficiency due to cancellation of bipolar cancellation (CANCAN-ES). We experimentally proved the CANCAN-ES paradigm by …

Phytoplankton Plastid Proteomics: Cracking Open Diatoms To Understand Plastid Biochemistry Under Iron Limitation, Skyler J. Nunn, Phoebe Dreux Chappell, Kristofer Gomes, Anasthasia Bonderenko, Bethany D. Jenkins, Brook L. Nunn

OES Faculty Publications

Diatoms, such as Thalassiosira pseudonana, are important oceanic primary producers, as they sequester carbon dioxide (CO₂) out of the atmosphere, die, and precipitate to the ocean floor. In many areas of the world’s oceans, phytoplankton, such as diatoms, are limited in growth by the availability of iron (Fe). Fe is an essential nutrient for phytoplankton, as it is central in the electron transport chain component of photosynthesis. Through this study, we examined if Fe-limitation makes a significant difference in the proteins expressed within the chloroplast, the power source for diatoms. Here, we utilized a new plastid isolation technique specific …

Selective Mutation Accumulation: A Computational Model Of The Paternal Age Effect, Eoin C. Whelan, Alexander C. Nwala, Christopher Osgood, Stephan Olariu

Biological Sciences Faculty Publications

Motivation: As the mean age of parenthood grows, the effect of parental age on genetic disease and child health becomes ever more important. A number of autosomal dominant disorders show a dramatic paternal age effect due to selfish mutations: substitutions that grant spermatogonial stem cells (SSCs) a selective advantage in the testes of the father, but have a deleterious effect in offspring. In this paper we present a computational technique to model the SSC niche in order to examine the phenomenon and draw conclusions across different genes and disorders.

Results: We used a Markov chain to model the probabilities of …

A Mesh Generation And Machine Learning Framework For Drosophila Gene Expression Pattern Image Analysis, Wenlu Zhang, Daming Feng, Rongjian Li, Andrey Chernikov, Nikos Chrisochoides, Christopher Osgood, Charlotte Konikoff, Stuart Newfeld, Sudhir Kumar, Shuiwang Ji

Computer Science Faculty Publications

Background: Multicellular organisms consist of cells of many different types that are established during development. Each type of cell is characterized by the unique combination of expressed gene products as a result of spatiotemporal gene regulation. Currently, a fundamental challenge in regulatory biology is to elucidate the gene expression controls that generate the complex body plans during development. Recent advances in high-throughput biotechnologies have generated spatiotemporal expression patterns for thousands of genes in the model organism fruit fly Drosophila melanogaster. Existing qualitative methods enhanced by a quantitative analysis based on computational tools we present in this paper would provide …

Mathematical Manipulative Models: In Defense Of "Beanbag Biology", John R. Jungck, Holly Gaff, Anton E. Weisstein

Biological Sciences Faculty Publications

Mathematical manipulative models have had a long history of influence in biological research and in secondary school education, but they are frequently neglected in undergraduate biology education. By linking mathematical manipulative models in a four-step process-1) use of physical manipulatives, 2) interactive exploration of computer simulations, 3) derivation of mathematical relationships from core principles, and 4) analysis of real data sets-we demonstrate a process that we have shared in biological faculty development workshops led by staff from the BioQUEST Curriculum Consortium over the past 24 yr. We built this approach based upon a broad survey of literature in mathematical educational …