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Full-Text Articles in Life Sciences

High Concentrations Of Trimethylamines In Slime Glands Inhibit Skein Unraveling In Pacific Hagfish, Gaurav Jain, Marie Starksen, Kashika Singh, Christopher Hoang, Paul Yancey, Charlene Mccord, Douglas S. Fudge Nov 2019

High Concentrations Of Trimethylamines In Slime Glands Inhibit Skein Unraveling In Pacific Hagfish, Gaurav Jain, Marie Starksen, Kashika Singh, Christopher Hoang, Paul Yancey, Charlene Mccord, Douglas S. Fudge

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Hagfish defend themselves from fish predators by producing large volumes of gill-clogging slime when they are attacked. The slime consists of seawater and two major components that are ejected from the slime glands: mucus and threads. The threads are produced within specialized cells and packaged into intricately coiled bundles called skeins. Skeins are kept from unraveling via a protein adhesive that dissolves when the skeins are ejected from the slime glands. Previous work revealed that hagfish slime glands have high concentrations of methylamines including trimethylamine N-oxide (TMAO), trimethylglycine (betaine) and dimethylglycine (DMG); however, the function of these compounds in the …


Plasticity Of Foot Muscle And Cardiac Thermal Limits In The Limpet Lottia Limatula From Locations With Differing Temperatures, Terrance Wang, Richelle L. Tanner, Eric J. Armstrong, David R. Lindberg, Jonathon H. Stillman Sep 2019

Plasticity Of Foot Muscle And Cardiac Thermal Limits In The Limpet Lottia Limatula From Locations With Differing Temperatures, Terrance Wang, Richelle L. Tanner, Eric J. Armstrong, David R. Lindberg, Jonathon H. Stillman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Species distributions are shifting in response to increased habitat temperatures as a result of ongoing climate change. Understanding variation in physiological plasticity among species and populations is important for predicting these distribution shifts. Interspecific variation in intertidal ectotherms’ short-term thermal plasticity has been well established. However, intraspecific variation among populations from differing thermal habitats remains a question pertinent to understanding the effects of climate change on species’ ranges. In this study, we explored upper thermal tolerance limits and plasticity of those limits using a foot muscle metric and 2 cardiac metrics (Arrhenius breakpoint temperature, ABT, and flatline temperature, FLT) in …


Coral Reef Change Detection In Remote Pacific Islands Using Support Vector Machine Classifiers, Justin J. Gapper, Hesham El-Askary, Erik Linstead, Thomas Piechota Jun 2019

Coral Reef Change Detection In Remote Pacific Islands Using Support Vector Machine Classifiers, Justin J. Gapper, Hesham El-Askary, Erik Linstead, Thomas Piechota

Mathematics, Physics, and Computer Science Faculty Articles and Research

Despite the abundance of research on coral reef change detection, few studies have been conducted to assess the spatial generalization principles of a live coral cover classifier trained using remote sensing data from multiple locations. The aim of this study is to develop a machine learning classifier for coral dominated benthic cover-type class (CDBCTC) based on ground truth observations and Landsat images, evaluate the performance of this classifier when tested against new data, then deploy the classifier to perform CDBCTC change analysis of multiple locations. The proposed framework includes image calibration, support vector machine (SVM) training and tuning, statistical assessment …


High Heat Tolerance Is Negatively Correlated With Upper Thermal Tolerance Plasticity In North Eastern Pacific Nudibranch Mollusks, Eric J. Armstrong, Richelle L. Tanner, Jonathon H. Stillman Jun 2019

High Heat Tolerance Is Negatively Correlated With Upper Thermal Tolerance Plasticity In North Eastern Pacific Nudibranch Mollusks, Eric J. Armstrong, Richelle L. Tanner, Jonathon H. Stillman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Rapid ocean warming may alter habitat suitability and population fitness for marine ectotherms. Susceptibility to thermal perturbations will depend in part on plasticity of a species’ upper thermal limits of performance (CTmax). However, we currently lack data regarding CTmax plasticity for several major marine taxa, including nudibranch mollusks, thus limiting predictive responses to habitat warming for these species. In order to determine relative sensitivity to future warming, we investigated heat tolerance limits (CTmax), heat tolerance plasticity (acclimation response ratio), thermal safety margins, temperature sensitivity of metabolism, and metabolic cost of heat shock in nine species …


Fusarium Euwallacea: A Serious Threat To The Native And Ornamental Trees And Shrubs In Southern California, Greg Tyler, Yixing Zheng, Michael Kulinich, Hagop Atamian May 2019

Fusarium Euwallacea: A Serious Threat To The Native And Ornamental Trees And Shrubs In Southern California, Greg Tyler, Yixing Zheng, Michael Kulinich, Hagop Atamian

Student Scholar Symposium Abstracts and Posters

Fusarium Euwallacea is a fungus that has established symbiotic relationship with the beetle Euwallacea aff. fornicata. The beetle bores through the tree bark and into the sapwood making long tunnels inside the trees. The beetle carries the F. Euwallacea in a specialized structure on its body called mandibular mycangia and cultivates the fungus in the tunnels on which the beetle feeds to grow and reproduce. The growth of the fungus obstructs water and mineral transport in the plant xylem tissue, resulting in dieback, wilt and mortality of the host tree. Fungi are known to secrete proteins called effectors in …


Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith Mar 2019

Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source …


Allosteric Mechanism Of The Circadian Protein Vivid Resolved Through Markov State Model And Machine Learning Analysis, Hongyu Zhou, Zheng Dong, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao Feb 2019

Allosteric Mechanism Of The Circadian Protein Vivid Resolved Through Markov State Model And Machine Learning Analysis, Hongyu Zhou, Zheng Dong, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

The fungal circadian clock photoreceptor Vivid (VVD) contains a photosensitive allosteric light, oxygen, voltage (LOV) domain that undergoes a large N-terminal conformational change. The mechanism by which a blue-light driven covalent bond formation leads to a global conformational change remains unclear, which hinders the further development of VVD as an optogenetic tool. We answered this question through a novel computational platform integrating Markov state models, machine learning methods, and newly developed community analysis algorithms. Applying this new integrative approach, we provided a quantitative evaluation of the contribution from the covalent bond to the protein global conformational change, and proposed an …


Concept Inventories As A Resource For Teaching Evolution, Robert E. Furrow, Jeremy L. Hsu Jan 2019

Concept Inventories As A Resource For Teaching Evolution, Robert E. Furrow, Jeremy L. Hsu

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Understanding evolution is critical to learning biology, but few college instructors take advantage of the body of peer-reviewed literature that can inform evolution teaching and assessment. Here we summarize the peer-reviewed papers on tools to assess student learning of evolutionary concepts. These published concept inventories provide a resource for instructors to design courses, gauge student preparation, identify key misconceptions in their student population, and measure the impact of a lesson, course, or broader curriculum on student learning. Because these inventories vary in their format, target audience, and degree of validation, we outline and explain these features. In addition to summarizing …