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Full-Text Articles in Life Sciences

Leaf Mechanical Strength Predicts Physiological Traits Among Three Life History Types In California Chaparral, Taylor S. Stucky, Nicole M. Rodriguez Purcell, Stephen D. Davis Aug 2013

Leaf Mechanical Strength Predicts Physiological Traits Among Three Life History Types In California Chaparral, Taylor S. Stucky, Nicole M. Rodriguez Purcell, Stephen D. Davis

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The Santa Monica Mountains of southern California are located in a Mediterranean-type climate region which experiences reoccurring wildfires due to summer drought and Santa Ana winds. Chaparral vegetation, which consists mostly of evergreen, sclerophyllous shrubs, dominates the landscape. Species of chaparral shrubs have evolved three different life history types in response to fire – those that sprout after fire but do not germinate seeds (obligate sprouters = OS), those that do not sprout after fire but reestablish by seed germination (non-sprouters = NS), and those that both sprout and germinate seeds after fire (facultative sprouters = FS). There are two …


Lysophosphatidic Acid Stimulates Lymphangiogenesis In Human Lymphatic Endothelial Cells, John Macbeth, Donna Nofziger-Plank Jul 2013

Lysophosphatidic Acid Stimulates Lymphangiogenesis In Human Lymphatic Endothelial Cells, John Macbeth, Donna Nofziger-Plank

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Lymphangiogenesis is the process by which new lymphatic vessels sprout and grow from existing vessels whether under developmental, immunological, or cancerous conditions. Proper lymphatic vessel formation is important in working alongside normal angiogenesis in order to help regulate the body’s tissue fluid as well as aid in immunosurveillance. Various factors regulate lymphangiogenesis such as members of the vascular endothelial growth factor family (VEGF). Another factor that has recently been identified to play a role in lymphangiogenesis is the bio-active phospholipid lysophosphatidic acid (LPA) however the molecular mechanism by which LPA regulates lymphangiogenesis has not been well characterized. In this study, …


The Survivin And Ciap1 Anti-Apoptotic Proteins Are Differentially Downregulated In Response To Endoplasmic Reticulum Stress, Vicki Mercado, Jay L. Brewster Jul 2013

The Survivin And Ciap1 Anti-Apoptotic Proteins Are Differentially Downregulated In Response To Endoplasmic Reticulum Stress, Vicki Mercado, Jay L. Brewster

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The endoplasmic reticulum (ER) is an organelle tasked with synthesis and transport of 50% of new cellular proteins. Dysfunction within this organelle creates signals for repair, adaptation, and in severe cases, cellular apoptosis. Multiple human diseases have been associated with ER dysfunction, and the activation of apoptosis in important populations of cells. Inhibitor of Apoptosis (IAP) proteins are cytosolic proteins that play an anti-apoptotic role in the cytosol. The relationship between endoplasmic reticulum (ER) stress and the expression/stability of IAPs is not well characterized. The objective of this study was to characterize the affect of ER stress on the expression/stability …


Evaluating Itpr-Dependence Of Apoptotic Signaling From The Endoplasmic Reticulum, Agustin Vargas, Jay L. Brewster Jul 2013

Evaluating Itpr-Dependence Of Apoptotic Signaling From The Endoplasmic Reticulum, Agustin Vargas, Jay L. Brewster

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Stress within the endoplasmic reticulum (ER) can be induced by misfolded proteins accumulating in the lumen of this organelle. Signaling of ER stress to other parts of the cell results in altered gene expression, physiological adaptation, and with sustained stress, apoptosis (cell suicide). ER stress is often studied with highly toxic compounds that create severe ER stress rapidly, and a condition that is likely not physiologically relevant within an organism. In this study, we examine the apoptotic signaling induced by moderate ER stress, and in particular the inositol 1,4,5-trisphosphate receptor (ITPR). The ITPR regulates Ca2+ release from the ER lumen, …


Carbon Black And Titanium Dioxide Nanoparticles Differentially Activate Oxidative Stress And Apoptosis In A549 Human Alveolar Epithelial Cells, Sarah Alvarado, Brianna Manes, Jay L. Brewster Jul 2013

Carbon Black And Titanium Dioxide Nanoparticles Differentially Activate Oxidative Stress And Apoptosis In A549 Human Alveolar Epithelial Cells, Sarah Alvarado, Brianna Manes, Jay L. Brewster

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Recent studies have demonstrated that variation between particulate matter compositions have universally adverse effects on cells and living tissues. Carbon black and titanium dioxide are two such particulates that we are continuously exposed to, yet there is limited research to examine the potential deleterious effects on living tissue. The objective of this study is to characterize the effect of carbon black (CB) and titanium dioxide (TiO2) particulates on A549 human alveolar epithelial lung cells. CB and TiO2 powders were dispersed throughout a solution of water and bovine serum albumin by high-powered sonication. The effects of these particulates on A549 cells …


Immunomodulatory Activity Of Sambucus Mexicana And Trichostema Lanatum On Lps Stimulated Raw 264.7 Macrophage Cells, Victoria Hester, P. Matthew Joyner Jul 2013

Immunomodulatory Activity Of Sambucus Mexicana And Trichostema Lanatum On Lps Stimulated Raw 264.7 Macrophage Cells, Victoria Hester, P. Matthew Joyner

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Chumash medicinal plants Sambucus mexicana (Mexican elderberry) and Trichostema lanatum (woolly blue curls) were tested for immunomodulatory activity. Anti-inflammatory effects were determined by treating LPS induced RAW 264.7 macrophage cells with plant extracts and measuring the levels of cytokines: tumor necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10). We hypothesized that both plants would exert immunomodulatory activity by reducing the pro-inflammatory production of TNF-alpha or by promoting M2 polarization with a concurrent increase in IL-10 production. At concentration 0.01 mg/mL woolly blue curls and Mexican elderberry demonstrated anti-inflammatory activity by reducing the concentration of TNF-alpha in vitro, while levels of …


The Regulatory Effect Of Semaphorin 7a On Proliferation And Migration In Human Umbilical Vein Endothelial Cells, Steven R. Flemming, Donna Nofziger-Plank Jul 2013

The Regulatory Effect Of Semaphorin 7a On Proliferation And Migration In Human Umbilical Vein Endothelial Cells, Steven R. Flemming, Donna Nofziger-Plank

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Semaphorin 7A (SEMA 7A), a factor originally identified as regulating axon growth, has recently been implicated as a pro-angiogenic factor. The molecular mechanisms for this ability to stimulate angiogenesis have not been identified. This study examines if SEMA 7A can have a direct effect on vascular endothelial cells or whether it indirectly induces angiogenesis through stimulation and recruitment of macrophages as has been suggested. Using a human umbilical vein endothelial cells (HUVECs), the ability of SEMA 7A to affect proliferation and migration was examined. HUVECs were exposed to SEMA 7A directly or to conditioned media collected from macrophages exposed to …


Effect Of Shear Stress On Ecnos Expression And Dilation In Soleus Feed Arteries, Blanca Perez, Jay L. Brewster, Jeffrey Jasperse Jul 2013

Effect Of Shear Stress On Ecnos Expression And Dilation In Soleus Feed Arteries, Blanca Perez, Jay L. Brewster, Jeffrey Jasperse

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Shear stress causes artery dilation and increased expression of endothelial cell nitric oxide synthase (ecNOS) in coronary and placental arteries. We sought to determine the importance of shear stress in maintaining normal dilation and normal levels of ecNOS in rat soleus feed arteries (SFA). SFA were isolated from male Sprague-Dawley rats and cannulated for in vitro microscopy (Fig. 6). SFA were exposed to no shear stress, low shear stress, or high shear stress conditions for 4 hours. After 4 hours, endothelium-dependent dilation (acetylcholine: ACh) and endothelium-independent dilation (sodium nitroprusside: SNP) were tested. Arteries were then uncannulated, mRNA was isolated, and …


An Ethnobotanical Approach To Finding Antimicrobial Compounds In Wooly Blue Curls (Trichostema Lanatum) Using A Kirby-Bauer Disc Diffusion Assay, Matthew C. Fleming, P. Matthew Joyner Jul 2013

An Ethnobotanical Approach To Finding Antimicrobial Compounds In Wooly Blue Curls (Trichostema Lanatum) Using A Kirby-Bauer Disc Diffusion Assay, Matthew C. Fleming, P. Matthew Joyner

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Plants can be an important source of creativity and production of new drugs. In this study, extracts of wooly blue curls (Trichostema lanatum) were made using DMSO and tested for antimicrobial activity on a panel of bacteria commonly found in separate ecological niches. Wooly blue curls (WBC) was chosen due to its being recorded as a strong disinfectant by the Chumash people. It was found that WBC does exhibit antimicrobial activity against gram positive bacteria and not against gram negative bacteria. However, gram negative bacteria with reduced drug efflux function became susceptible to the WBC extract.


The Effect Of Shear Stress, Potassium, And Adenosine On Α-1 Adrenergic Vasoconstriction Of Rat Soleus Feed Arteries, Tanner J. Heckle, Jeffrey Jasperse Jul 2013

The Effect Of Shear Stress, Potassium, And Adenosine On Α-1 Adrenergic Vasoconstriction Of Rat Soleus Feed Arteries, Tanner J. Heckle, Jeffrey Jasperse

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During exercise, blood flow increases to the working skeletal muscle primarily because of dilation of the arteries and arterioles feeding the muscle. Sympathetic nerve activity also increases during exercise, augmenting the release of the neurotransmitter norepinephrine (NE) at the arterial wall and into the blood. NE acts to constrict blood vessels; however, arteries and arterioles within contracting skeletal muscle dilate despite the increased NE present. This has led to the concept of functional sympatholysis (4), the idea that a chemical released from contracting skeletal muscle interferes with NE signaling. NE acts by binding to adrenergic (alpha and beta) receptors, and …


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 Jan 2013

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

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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.


Varying Carbon Dioxide Levels And Its Effects On Malsoma Laurina’S Photosynthetic Rate, John A. Lawlor, Dustyn T. Zierman-Felix, Michael P. Schlagel Jan 2013

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

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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. …


Difference In Water Status Between Oak Trees (Quercus Berberidifolia) With Brown And Green Leaves During Severe Drought, Mia Bryant, Hannah Dario, Cameron Kline Jan 2013

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

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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 …


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 Jan 2013

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

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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 …


Post-Fire Recovery Of Juglans Californica In Sycamore Canyon: Water Potential And Site Characterization, Ariel Lan, Caitlin Thompson, Victoria Lekson Jan 2013

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

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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 Jan 2013

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

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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 Jan 2013

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

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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 …