Biology Commons^™

Difference In Water Status Between Oak Trees (Quercus Berberidifolia) With Brown And Green Leaves During Severe Drought, Mia Bryant, Hannah Dario, Cameron Kline

Featured Research

In this experiment, we examined cavitation in Quercus berberidifolia plants. We hypothesized that as the amount of water stress increases, then the pressure to cause embolism will decrease. We thought this because as a plant loses more water, the more air bubbles will form within the plant and therefore the pressure to cause this will decrease. We tested this hypothesis by comparing dry Quercus berberidifolia to more hydrated Quercus berberidifolia in Tapia Park, near Malibu, California. We measured and compared these plants by the use of the Scholander Pressure chamber and a parometer. In the end, we discovered that our …

Varying Carbon Dioxide Levels And Its Effects On Malsoma Laurina’S Photosynthetic Rate, John A. Lawlor, Dustyn T. Zierman-Felix, Michael P. Schlagel

Featured Research

The Keeling Curve has displayed an exponential increase in carbon dioxide within the earth’s atmosphere since the late 1950’s. Scientists have heatedly debated the effects that will occur as a result of this relatively new phenomenon (since the Industrial Revolution of America). We tested the effect of increased carbon dioxide levels on plant life, Malosma laurina, in particular. Our experiment involved the application of 400 PPM of carbon dioxide into different specimens of M. laurina and 800 PPM of carbon dioxide into the same specimens. We then recorded the rate of photosynthesis, conductance results, and levels of internal carbon dioxide. …

A Comparison Of Water Availability In Coastal Live Oak (Quercus Agrifolia) And California Bay (Umbellularia Californica) At Top And Bottom Of Hillsides At Malibu Creek State Park, California, Jake Szarzynski, Marley Biyendolo, Jeremy Goldenetz, Ann Alcazar

Featured Research

This investigation serves to show whether moisture content is different in plants at the top of hills versus bottom of hills, specifically comparing values of Quercus agrifolia and Umbellularia californica in Malibu Creek State Park. By acquiring six branches of each species on a hill at intervals of twenty feet, the moisture content can be obtained and analyzed by using the Scholander Hammel pressure chamber. This allows us to determine whether there is a correlation between moisture content and plant position on hills.

Impact Of Reclaimed Water On Photosynthetic Performance In Green Bark Ceanothus (Ceanothus Spinosus), Erika De Leener, Michael L. Gribble, Joshua D. Volkmar, Luo J. Zhao

Featured Research

The sprinkled water on the campus of Pepperdine University is primarily reclaimed water from sinks, toilets and showers on campus. The water is treated with micro bacteria and sand rocks to remove larger particles, smaller nitrogen containing compounds, excess nutrients and human pathogens. The Mediterranean weather in Southern California is characterized by dry summers, and watering plants by reclaimed water helps relieve the water stress in the community. However, the reclaimed water might distort the normal physiology of native plants on campus. We hypothesize that because nitrogen containing compounds cannot be efficiently removed by micro bacteria, higher nitrogen content in …

Social Aggregation In Pea Aphids: Experiment And Random Walk Modeling, Christa Nilsen, John Paige, Olivia Warner, Benjamin Mayhew, Ryan Sutley, Matthew Lam '15, Andrew J. Bernoff, Chad M. Topaz

All HMC Faculty Publications and Research

From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. …

Potential And Realized Nutrient Resorption In Serpentine And Non-Serpentine Chaparral Shrubs And Trees, Rebecca E. Drenovsky, Catherine E. Koehler, Kathryn Skelly, James H. Richards

Biology

Low-nutrient adapted species have numerous mechanisms that aid in nutrient conservation. Hypothetically, species adapted to nutrient-poor soils should have tighter internal nutrient recycling, as evidenced by greater resorption. However, literature results are mixed. We suggest methodological factors may limit our understanding of this process. We hypothesized that plants adapted to serpentine soils would be more proficient in resorbing N and P than plants adapted to non-serpentine soils, although there would be differences among functional groups within each soil type. For six growing seasons, we sampled senescent leaf tissue from the dominant and co-dominant shrubs and trees found in serpentine and …

Tidal Marsh Plant Responses To Elevated Co2, Nitrogen Fertilization, And Sea Level Rise, J. Adam Langley, Thomas J. Mozdzer, Katherine A. Shepard, Shannon B. Hagerty, J. Patrick Megonigal

Biology Faculty Research and Scholarship

Elevated CO₂ and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO₂ concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO₂ and N alter the …

Lifelines Winter 2013, Southern Adventist University

Lifelines - Biology Department Newsletter

The Winter 2013 issue of Lifelines features updates on research being conducted in the Biology Department, updates to the Biology Trail, student missions to Familia Feliz in Bolivia, and a pictorial directory of the 2013 biology and allied health graduates.

Trophic Ecology Of A Freshwater Sponge (Spongilla Lacustris) Revealed By Stable Isotope Analysis, J Skelton, Mac Strand

Faculty Works

No abstract provided.

Kinetic Models Reveal The In Vivo Mechanisms Of Mutagenesis In Microbes And Man, Barbara E. Wright, Karen H. Schmidt, Michael F. Minnick

Biological Sciences Faculty Publications

This review summarizes the evidence indicating that mutagenic mechanisms in vivo are essentially the same in all living cells. Unique metabolic reactions to a particular environmental stress apparently target specific genes for increased rates of transcription and mutation, resulting in higher mutation rates for those genes most likely to solve the problem. Kinetic models which have demonstrated predictive value are described and are shown to simulate mutagenesis in vivo in Escherichia coli, the p53 tumor suppressor gene, and somatic hypermutation. In all three models, direct correlations are seen between mutation frequencies and transcription rates. G and C nucleosides in single-stranded …

Prolonged Dormancy Interacts With Senescence For Two Perennial Herbs, Juha Tuomi, Elizabeth E. Crone, Jennifer R. Gremer, Anne Jakalaniemi, Peter Lesica, Bard Pedersen, Satu Ramula

Biological Sciences Faculty Publications

1. Senescence is characterized by a decline in survival, fecundity and reproductive value with age among adult individuals. Simple age-dependent life cycles progress forward through developmental stages, with each successive stage being characterized by age-specific vital rates. In contrast, size- or stage-based life cycles for perennial plants are more complex and often include stasis and retrogression to previous vegetative or reproductive life stages, indicating possible slowing or even reversing the developmental progress.

2. Many plants remain in nonemergent, below-ground stages during the growing season (prolonged dormancy), which may affect the process of senescence. Stasis in the dormant stage implies that …

Morphological And Ecological Segregation Of Two Sympatric Lomatium Triternatum (Apiaceae) Varities In Montana, Peter Lesica, Pamela Kittelson

Biological Sciences Faculty Publications

The Lomatium triternatum complex is widespread in the Columbia River Basin. Lomatium triternatum (Pursh) J. M. Coult. & Rose var. triternatum and L. triternatum (Pursh) J. M. Coult. & Rose var. anomalum (M. E. Jones ex J. M. Coult. & Rose) Mathias are sympatric throughout much of their range and are reported to have similar fruit but different leaves. Plants of the two varieties repeatedly occur within 5–30 m of each other at an unusual site in northwest Montana, USA. We collected data on leaf and fruit morphological characters and habitat associations at this site to help address whether the …

Chimeric Glutathione S-Transferases: Properties And Thermodynamic Stability, Rita M. Rozmarynowycz

ETD Archive

No abstract provided.

Evolutionary Novelty Versus Exaptation: Oral Kinematicsin Feeding Versus Climbing In The Waterfall-Climbing Hawaiian Goby Sicyopterus Stimpsoni, Richard W. Blob, Joshua Cullen, Takashi Maie, Heiko L. Schoenfuss

Publications

Species exposed to extreme environments often exhibit distinctive traits that help meet the demands of such habitats. Such traits could evolve independently, but under intense selective pressures of extreme environments some existing structures or behaviors might be coopted to meet specialized demands, evolving via the process of exaptation. We evaluated the potential for exaptation to have operated in the evolution of novel behaviors of the waterfall-climbing gobiid fish genus Sicyopterus. These fish use an ‘‘inching’’ behavior to climb waterfalls, in which an oral sucker is cyclically protruded and attached to the climbing surface. They also exhibit a distinctive feeding …

Estrogen Receptor Α Regulates Erk In Mcf-7 Cells, John M. Schmitt, Angela J. Rofelty

Faculty Publications - Department of Biological & Molecular Science

Abstract Estrogen (E2) signaling significantly affects breast tumorigenesis by enhancing cell growth and preventing apoptosis. The actions of estrogen in MCF-7 breast cancer cells are mediated through a kinase pathway involving CaM KK, CaM KI, and ERK. Current research is examining the involvement of the Estrogen Receptor (ER) alpha (α) and beta (β) as well as G-Protein Coupled Receptor GPR30 in cell growth and proliferation. ERα is suggested to be responsible for ERK and perhaps CaM Kinase activation. Our goal was to evaluate if ERα, rather than GPR30 or ERβ, mediates CaM KI and ERK activation upon treatment of MCF-7 …

Metabolism Of Brain Cortex And Cardiac Muscle Mitochondria In Hibernating 13-Lined Ground Squirrels Ictidomys Tridecemlineatus., Kirsten Gallagher, James F Staples

Biology Publications

During bouts of torpor, mitochondrial metabolism is known to be suppressed in the liver and skeletal muscle of hibernating mammals. This suppression is rapidly reversed during interbout euthermic (IBE) phases, when whole-animal metabolic rate and body temperature (T(b)) return spontaneously to euthermic levels. Such mitochondrial suppression may contribute significantly to energy savings, but the capacity of other tissues to suppress mitochondrial metabolism remains unclear. In this study we compared the metabolism of mitochondria from brain cortex and left ventricular cardiac muscle between animals sampled while torpid (stable T(b) near 5°C) and in IBE (stable T(b) near 37°C). Instead of isolating …

The Role Of Color And Contrast In Mate Choice Of Guppies, Alexis Owens, Michael Strange, Tammi Seamans, Marc Jolley, Rashelle Johnson

Biology Posters

No abstract provided.

Induction Of Liver Abcg5/Abcg8 Expression Is An Important Determinant Of The Macrophage-To-Feces Reverse Cholesterol Transport Response To Treatment With Ezetimibe, Jessica B. Altemus

ETD Archive

Reverse cholesterol transport (RCT) consists of the transfer of cholesterol from peripheral tissues for excretion in the feces. The RCT from macrophages in atherosclerotic lesions is an important determinant of arterial wall atherosclerotic lesion formation. Previous studies by our group have shown that treatment with ezetimibe (EZ), a potent inhibitor of cholesterol absorption from the intestine, results in a 2-6 fold increase in RCT. To determine whether EZ may increase RCT by mechanisms that are independent of its well established cholesterol absorption inhibitory effects, we examined the expression of genes involved in the RCT pathway in the jejunum and liver …

Responses To Low Double-Strand Break Levels In Budding Yeast Meiosis, Scott A. Gaskell

ETD Archive

During meiosis, one round of DNA replication is followed by two rounds of chromosome segregation, producing four haploid gametes from each diploid precursor cell. Self-inflicted DNA double-strand breaks (DSBs) occur in prophase of meiosis I. A subset of DSBs are repaired using the homologous chromosome as template for homologous recombination, generating crossovers/chiasmata. When processing of DSBs is defective, the recombination checkpoint delays onset of the first meiotic cell division. Here, I have investigated mechanisms by which the budding yeast S. cerevisiae responds to low levels of initiating DSBs. A novel checkpoint is identified that is specifically triggered by low DSB …

Bioinformatic Analysis And In Vitro Expression Of Malaria Parasite Translocon And Ribonuclease Binding-Like Rhoptry Genes, Moses Z. Timta

ETD Archive

Malaria caused by the parasite Plasmodium, still remains a significant public health problem worldwide, due to lack of a vaccine and emerging drug and insecticide resistance, among malaria parasites and mosquito vectors, respectively. Rhoptry proteins of Plasmodium enable merozoite invasion of host erythrocytes. However, only a few of these proteins have been characterized. Thirty-six P. yoelii merozoite rhoptry proteins were identified as putative rhoptry proteins by proteome analysis. Some of these proteins have been characterized while others still remain an intense area of active research. Molecular characterization and understanding of these novel proteins may assist in vaccine development, design of …

Identification Of New Genes Involved In Meiosis By A Genetic Screen, Sneharthi Banerjee

ETD Archive

Budding yeast Saccharomyces cerevisiae contains a group of proteins named ZMM that constitutes a link between recombination and Synaptonemal Complex (SC) assembly. Yeast mutants that lack ZMM proteins have defects in recombination, SC formation and nuclear division progression. Meiotic cell cycle progression in zmm mutants is modulated by temperature. This conditional behavior is different at high and low temperatures. In my work so far, I have tried to identify new zmm-like genes involved in meiosis. To that end, I have carried out a genome-wide screen in the budding yeast S. cerevisiae. I have identified sporulation temperature sensitive zmm-like truncation mutants …

Genomic Correlates Of Relationship Qtl Involved In Fore- Versus Hind Limb Divergence In Mice, Mihaela Palicev, Gunter P. Wagner, James P. Noonan, Benedikt Hallgrimsson, James M. Cheverud

Biology: Faculty Publications and Other Works

Divergence of serially homologous elements of organisms is a common evolutionary pattern contributing to increased phenotypic complexity. Here, we study the genomic intervals affecting the variational independence of fore- and hind limb traits within an experimental mouse population. We use an advanced intercross of inbred mouse strains to map the loci associated with the degree of autonomy between fore- and hind limb long bone lengths (loci affecting the relationship between traits, relationship quantitative trait loci [rQTL]). These loci have been proposed to interact locally with the products of pleiotropic genes, thereby freeing the local trait from the variational constraint due …

What Undergraduates In Biology Don't Know About Plant Structure And Growth, Kathleen Archer, Maryann Herman, Grace Miller, Laura Olsen, Jodie Ramsay

Biology Faculty/Staff Publications

We were interested to know what undergraduates in biology understand about plant structure and growth, and in particular what misconceptions they hold. To date, there has been no comprehensive analysis of what college undergraduates know about this topic, so we designed a study to address this deficiency. Students at two liberal arts colleges, two mid-sized universities (both public and private) and one research university were interviewed one-on-one. They were asked a series of open-ended questions addressing how plants grow taller, grow in diameter, move water and organics, produce leaves, etc. All students had at least one semester of either introductory …

Fall 2013, Nova Southeastern University

Currents

No abstract provided.

Assay Development For Determining The Anthelmintic Effect Of Plant Extracts On The Hookworm Ancylostoma Ceylanicum, Sarah Mcnutt

Undergraduate Honors Theses

Hookworm infections are one of the most common parasite infections in the world, infecting over 600 million people worldwide, mainly in impoverished areas. The current major approach to treating hookworm is periodic deworming with benzimidazoles. However, the frequent mass drug treatment has lead to a serious problem of drug resistance. Thus, efforts are moving towards developing new drugs and vaccines. We worked towards developing an assay to test the anthelmintic effect of plant extracts. The assays we developed tested the ability of samples to debilitate helminth worms to the point where they can no longer attach to the lining of …

Protein-Protein Interactions In The Neocortex: Emx2 And Its Binding Partners, Cierra Miller

Undergraduate Honors Theses

The mammalian neocortex is divided into discrete functional areas that are marked by distinct boundaries and whose positions are assigned through a process called neocortical arealization. One of the proteins involved in this process is Emx2, a transcription factor (protein that turns genes on and off) that is expressed, or made, in a gradient along the axis of the neocortex and determines the positions of these areal boundaries. In order to determine how Emx2 carries out this function of assigning areas, we have identified the proteins QKl-7 and Cnot61 as binding partners of Emx2.

Current research involves confirming the interactions …

Post-Fire Recovery Of Juglans Californica In Sycamore Canyon: Water Potential And Site Characterization, Ariel Lan, Caitlin Thompson, Victoria Lekson

Featured Research

Our study focused on post-fire recovery in the California Black Walnut, Juglans californica. Our study was conducted Sycamore Canyon, an area of the Santa Monica Mountain Range recently damaged by the April 2013 fires. Part of our study focused on water potential and water stress among J. californica; we examined differences in the water potentials of mature, unburned trees and resprouts which have grown since the fires in April. We found that mature trees have a significantly higher water potential than sprouts, either epicormic or basal, which indicates that they are better equipped to handle water stress. We also found …

Post-Fire Recovery Of Juglans Californica In Sycamore Canyon: Vessel Length, Shading, Water Use Efficiency And Water Status, Victoria Lekson, Anushree Mahajan

Featured Research

In April 2013, Sycamore Canyon experienced a major wildfire. This study investigates post-fire recovery of two types of resprouts, basal and epicormic, and compares multiple parameters to mature unburned Juglans californica. In this study, we investigate the influence of time of day on the post-fire water potential of mature unburned plants versus burned Juglans californica epicormic and basal resprouts. One way ANOVA test reveals p

The Effect Of Freezing Conditions On Xylem Diameter Of Malosma Laurina And Umbellularia Californica In The Santa Monica Mountains, Nicole A.P.M.K.O.M. Nakamatsu, Theadora V. Ordog, Kaitlyn E. Sauer

Featured Research

Temperature variations in the Santa Monica Mountains are drastic at times, which may be affecting the local plants. To determine the repercussions of these variations in temperature, we measured the xylem diameters of freezing and non-freezing Malosma laurina and Umbellularia californica. U. californica was chosen because it has a large xylem diameter, yet is known to survive freezing conditions. We thought that this plant could provide the most significant results to prove or disprove our hypothesis. M. laurina was chosen because it is abundant in the Santa Monica Mountains and has different physical dimensions than U. californica. Smaller xylem diameters …

Acyl-Lipid Metabolism, Younghua Li-Beisson, Basil Shorrosh, Fred Beisson, Mats X. Andersson, Vincent Arondel, Philip D. Bates, Sébastien Baud, David Bird, Allan Debono, Timothy P. Durrett, Rochus B. Franke, Ian A. Graham, Kenta Katayama, Amélie A. Kelly, Tony Larson, Jonathan E. Markham, Martine Miquel, Isabel Molina, Ikuo Nishida, Owen Rowland, Lacey Samuels, Katherine M. Schmid, Hajime Wada, Ruth Welti, Changcheng Xu, Rémi Zallot, John Ohlrogge

Scholarship and Professional Work - LAS

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes …