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Relating Leaf Temperature On Malosma Laurina To Leaf Proximity From Soil, Brooks O'Hea, Kevin Morgan

Featured Research

The Santa Monica Mountains are home to countless vegetation and plant species, many of which have been forced to adapt to southern California’s stressful environment. With recent droughts and a steady change in climate, an increase in leaf temperature within some species in the Santa Monica Mountains has been observed. One prominent plant found within the mountain range is the malosma laurina, or laurel sumac, the only species of the malosma genus. Malosma laurina is a perfect example of a specie adapting to its stressful environment. Constant brush and shrub fires within the chaparral area where it commonly grows have …

Comparison Of Photosynthetic Ability In Single And Double Palisade Parenchyma Leaves In Southern California, Vincent Quach, Ryan Sauer, Haley Smith, Christian Wright

Featured Research

Melaleuca quinquenervia is a myrtle (family Myrtaceae) with a propensity for invasiveness. The leaves feature an isobilateral orientation: vertically aligned with a layer of palisade parenchyma on both the adaxial and abaxial sides. Quercus agrifolia (Fagaceae) is a native evergreen with one layer of palisade parenchyma. Due to this structural difference, it was hypothesized that Melaleuca would have a higher rate of photosynthesis (Pn) and less reflectance (NDVI) of green light than Quercus. These two variables were compared using an unpaired t-test, yielding p-values of 0.1366 for NDVI and 0.04428 for photosynthetic rate. No significant difference was found between the …

Measuring Water Potential Among Crassula Ovata And Heteromeles Arbutifolia, Monét Mcnally, Stephanie Yakupitiyage, Jamille Lockhart

Featured Research

Chaparral shrubs are known for their abilities to withstand dry environments. Both the California native C3 plant, Heteromeles arbutifolia, also known as Hollywood, and the CAM plant, Crassula ovata, also know as a Jade plant, have the ability to thrive under a Mediterranean-like climate region. However, during severe cases of drought one plant may better adapted than the other. The purpose of this experiment is to determine whether Heteromeles arbutifolia or Crassula ovata is better able to withstand drought by measuring the dehydration rate. We calculated the leaf-area to mass ratio and the change in water potential of each species …

Relationship Between Canopy Location And Tensile Strength Of Leave Of Heteromeles Arbutifolia In Malibu, Ca, Elena Witham, Melinda Marchiano, Danielle Reynolds

Featured Research

Our hypothesis is that canopy location has an effect on the characteristic tensile strength of leaves, with the leaves on the top of the canopy having greater strength than the leaves on the bottom. We tested our experiment by sampling leaves from the top and bottom of three H. arbutifolia specimens, obtaining raw measurements of size, and testing the tensile strength of each leaf using the Instron. We performed t-tests on the data to determine if the average length, width, thickness, and tensile strength were statistically different depending on if our p values were < 0.05 when top and bottom leaves of the same tree were compared. We chose a chapparral stand removed from heavy human traffic and influence, eliminating as many extraneous variables as possible by taking leaves from the same tree of the same age from the same position on the branch and chose three trial specimen of similar height in the same area to reduce the possibility of varying sunlight exposure or water supply from affecting leaf morphology in a way that canopy position would not. The results show that blade length between top and bottom is statistically significantly different, while blade thickness and lateral strength at midsection were not statistically different. From our analysis of the data, it is clear that leaves on the bottom of the plant were longer and broader than leaves on the top, but we determined that canopy location does not have a major effect on tensile strength or thickness, supporting a null hypothesis.

Relationship Between Canopy Location And Tensile Strength Of Leaves Of Heteromeles Arbutifolia In Malibu, Ca, Elena Witham, Melinda Marchiano, Danielle Reynolds

Featured Research

Our hypothesis is that canopy location has an effect on the characteristic tensile strength of leaves, with the leaves on the top of the canopy having greater strength than the leaves on the bottom. We tested our experiment by sampling leaves from the top and bottom of three H. arbutifolia specimens, obtaining raw measurements of size, and testing the tensile strength of each leaf using the Instron. We performed t-tests on the data to determine if the average length, width, thickness, and tensile strength were statistically different depending on if our p values were < 0.05 when top and bottom leaves of the same tree were compared. We chose a chapparral stand removed from heavy human traffic and influence, eliminating as many extraneous variables as possible by taking leaves from the same tree of the same age from the same position on the branch and chose three trial specimen of similar height in the same area to reduce the possibility of varying sunlight exposure or water supply from affecting leaf morphology in a way that canopy position would not. The results show that blade length between top and bottom is statistically significantly different, while blade thickness and lateral strength at midsection were not statistically different. From our analysis of the data, it is clear that leaves on the bottom of the plant were longer and broader than leaves on the top, but we determined that canopy location does not have a major effect on tensile strength or thickness, supporting a null hypothesis.

Correlation Between Freezing Sites And Xylem Vessel Diameter For Three Chaparral Species Of The Santa Monica Mountains, Kaitlyn E. Sauer, Theodora V. Ordog, Nicole A.P.M.K.O.M. Nakamatsu

Featured Research

Coastal exposures of the Santa Monica Mountains rarely experience freezing temperatures

(0 °C) because of the ameliorating effects of the Pacific Ocean and seawater’s specific heat capacity. In contrast, inland sites of the Santa Monica Mountains frequently experience winter temperatures below -10 °C. This temperature gradient, from coast to inland, may be a major determinate of species distribution patterns. To investigate possible mechanisms by which freezing impacts chaparral distribution patterns, we examined xylem vessel diameter and vessel length of three chaparral species growing at inland freezing sites versus coastal nonfreezing sites (Malosma laurina, Umbellularia californica, and Ceanothus megacarpus). It has …

Measuring Photosynthesis To Evaluate Photoprotection By Anthocyanins In Malosma Laurina, Jorge Bojorkez-Calderon, Hannah Imson

Featured Research

The purpose of this investigation was to observe the differences between the photosynthetic rates and photo-protection of young, red, juvenile leaves of Malosma laurina, and compare it to young, green leaves. To accomplish this, the open-system of Li-6400 XT was brought out into the field to a shrub of Malosma laurina that was flourishing and had both red and green leaves present. Then, data of fluorescence, photosynthetic rate, and conductance was taken from both red leaves and green leaves, and the photosynthetic rates were compared. Through this investigation, we were able to quantify that in young, red leaves, which had …

The Effects Of Higher And Lower Co2 Levels In The Atmosphere On The Photosynthetic Rates And Stomatal Conductance Of Malosma Laurina In The Santa Monica Mountains, Victoria A. Thorsen, Maverick E. Turner, Colby P. Harriman

Featured Research

We hypothesize that higher CO2 levels will lead to a change in photosynthetic performance in the Malosma laurina population of the Santa Monica Mountains. We used one Malosma laurina that is across the street from university’s theme tower. We chose this specific plant because it was in the sun and it was in a well irrigated area. We selected a plant that is in non-shaded areas at 12:00 pm and then dark adapt them for 20 minutes. We selected an adult plant that was between four and six feet tall. We took the measurements from the upper leaves of the …

Relationship Between Dehydration Tolerance Of California Ferns And The Mechanical Strength Of Their Stipes, Helen I. Holmlund, Jarmila Pitterman, Stephen D. Davis

Featured Research

In vascular plants, water moves upwards through xylem vessels/tracheids due to negative pressures created by the evaporative pull of water. Under severe dehydrated, extreme negative pressures are known to cause xylem cavitation and embolism. In seed-bearing plants, the mechanical support of stem xylem has been shown to be a good predictor of cavitation resistance, presumably because sclerenchyma fibers buttress against micro-fracture or collapse of conduit walls. In spore-bearing plants, such as ferns, current anatomical theory indicates that mechanical support lies external to underlying xylem, in the outer hypodermal region, leaving the central xylem in ferns without any fiber support. In …

Vegfr-2 And Vegfr-3 Expression As A Function Of Jagged-1 Over-Expression In Huvec Cells, Caleb Stubbs

Featured Research

Angiogenesis is the sprouting of new blood vessels from pre-existing vessels initiated from vascular endothelial cells in response to exogenous chemical signals. Principle signals are vascular endothelial growth factors (VEGF) that direct cell growth and differentiation by binding to endothelial cell surface VEGF receptors (VEGFR). In Human Umbilical Vascular Endothelial Cells (HUVEC) initial sprouting cells or “tip cells” send signals to neighboring cells “stalk cells” responsible for sprout elongation. Multiple VEGF signals and receptors are known, but the main angiogenic signals are from VEGF-A through VEGFR-2 and VEGFR-3. Regulation of VEGF receptor expression can be influenced by the Notch signaling …

Effect Of Shear Stress Direction On Endothelial Function And Enos Phosphorylation In Soleus Feed Arteries, Blanca B. Perez, Jay Brewster, Jeffrey Jasperse

Featured Research

Blood flow feeding tissues and organs is closely regulated in order to meet metabolic and functional needs. Control of blood flow is accomplished by regulating the diameter of the arteries and arterioles feeding different organs. Several neural, hormonal, chemical and mechanical mechanisms contribute to the constriction and dilation of arteries. Shear stress, the frictional force created by streaming blood on the endothelial layer of arteries, is one of these mechanical mechanisms (1). Shear stress causes both acute and long term effects on endothelial cells (1,2,5).

Blood in arteries typically flows away from the heart towards organs (causing antegrade shear stress) …

Differential Survival Of Chaparral Shrub Species In Response To Severe Drought, Hannah Dario

Featured Research

In this experiment, we examined how the plants in the Santa Monica Mountains are responding to the driest period in recorded history for California. Our hypothesis was that plant species with the deepest roots would have highest survivorship. We thought this because deep-rooted shrubs will have greater access to soil moisture. This hypothesis was tested by collecting data on plant survival, in a mixed chaparral stand, containing eleven species, growing in the Green Valley Preserve off of Stunt road, in the Santa Monica Mountains. The chaparral stand was 21 years old, having last burned in 1993 (Old Topanga Canyon Fire). …

Effects Of Uv-Radiation On Feeding Behavior In Dendrobates Tinctorius, Taylor S. Stucky, Arthur Garnica

Featured Research

UV-B levels have recently been increasing with the depletion of the ozone layer. Recent data have shown that amphibians are especially susceptible to UV-B, with poison dart frogs being one focus in these studies. The purpose of this study was to determine if UV-B radiation affects the foraging behavior of poison dart frogs. This study was conducted with a captive population of juvenile Dendrobates tinctorius at Pepperdine University in Malibu, California. Frogs underwent one of three treatments: UV only, Food only, and UV and Food. UV only trials were conducted using two UV lights emitting approximately 1.2 uW/cm2 of UV …

Enzymatic Activity In The Chorion For Hatching In The California Grunion, Emily R. Pierce, Vince V. Quach, Karen L. Martin

Featured Research

Leuresthes tenuis is a small, silverside fish that spawns on the beaches during some of the highest tides of the summer months. Of the many unique traits to the species including that the eggs develop fully out of water to the point of hatching competence but will not hatch until presented with an environmental cue, which causes them to hatch in less than a minute. The purpose of this study is to better understand the role of enzymes called chorionases, which act to break down the chorion (egg membrane). I hypothesize that the chorion begins to weaken in this species …

The Effects Of Carbon Black On Cell Viability, Abigail Calixto, Jay Brewster

Featured Research

Carbon black (CB) is a type of nanoparticle that is found in air pollution and is a known environmental toxin. The purpose of this work is to evaluate whether CB exposure activates cell death via apoptosis in cultured cell lines, supporting future work focused upon assessing the signaling pathways that might be induced by this exposure. Using adenocarcinomic human alveolar basal epithelial (A549) and baby hamster kidney (BHK-21) cells, we hypothesized that carbon black exposure causes cell death and potentially stress signaling via the endoplasmic reticulum (ER). The cells were exposed to CB and data collected for varied doses and …

The Mechanical Strength Of Malosma Laurina Leaves Corresponds With Survivability During Extreme Drought, Alexander Booth, Alexander Corwin, Matthew Chung

Featured Research

With the recent extreme drought that Southern California is facing, many plants’ survivability adaptations have proven insufficient. The Malosma laurina plant is known for it’s incredible ability to survive through droughts and wildfires with it’s adaptations of resprouts regeneration and it’s roots that can reach a depth of 40 feet to gather deep ground waters. We theorized that the mechanical strength of the leaves directly relates to its survivability during droughts. To explore this theory we took focused our theory specifically on M. laurina resprouts. With two groups, one fully alive and one dying, we took six samples from six …

Ethnobotanical Promotion Of Fibroblast Growth Using Yerba Santa Extract, Carlie F. Dobbins, Paige A. Sutherland, Emily A. Woods

Featured Research

Ethnobotany is a promising way of discovering new drugs, drawing on the knowledge of generations of traditional healers. The healing qualities of Yerba Santa (Eriodictyon crassifolium) have been recognized for hundreds of years by Chumash Indians and Spanish missionaries, so much so that they came to call it “holy herb”. We decided to determine the efficacy of Yerba Santa by extracting potentially bioactive molecules in methanol and then using this extract to treat scales from goldfish (Carassius auratus) to test the hypothesis that the Yerba Santa extract would alter the growth of fibroblasts. Compared to scales treated with only modified …

Leaf Mechanical Strength Corresponds To Tissue Water Relations In Twelve Species Of California Ferns, Breahna M. Gillespie, Stephen D. Davis, Jarmila Pitterman

Featured Research

The dominant vegetation types in southern California’s coastal foothills are chaparral and costal sage scrub. Chaparral shrubs have mechanically strong evergreen leaves whereas coastal sage scrubs bear mechanical weak, facultative deciduous leaves. What about the ferns that live in the understory of these vegetation types, especially considering their adaptations to a summer dry, Mediterranean-type climate? We tested the hypothesis that some fern leaves are stronger than others and mechanically strong leaves are associated with greater dehydration tolerance. Twelve fern species were examined. Tissue water relations were assessed via pressure volume curves using Scholander-Hammel pressure chambers. We estimated osmotic potential at …

Ethnobotanical Promotion Of Fibroblast Growth Using Yerba Santa Extract, Carletta F. Dobbins, Paige A. Sutherland, Emily A. Woods

Featured Research

Ethnobotany is a promising method for discovering new drugs, drawing on the knowledge of generations of traditional healers. For hundreds of years, the Chumash people have lived in the coastal regions of California, becoming experts on the many uses of its natural resources. One such resource is the Yerba Santa plant (Eriodictyon crassifolium), which was used by the Chumash to treat a myriad of conditions including coughs, chest pain, and fever. It was also used as a poultice on wounds and cuts, suggesting that the plant has a stimulating effect on the growth of skin cells. Because of these qualities, …

Planetary Heat Sink Uncouples Temperature Increase From Rising Co2: Climate Change Hiatus Explained, Monica Houweling, Megan Gavitt, Jean Kim

Featured Research

The current hiatus in terms of global climate change has been linked to a greater phenomenon of a change in climate than seen in previous historical trends. The globe was rising in temperature throughout the beginning of the 21st century, but has entered into a hiatus, a period where the CO2 levels continue to rise but the global temperature is remaining constant. It is predicted that temperatures will continue to rise once this hiatus passes. The main cause of this hiatus, known as planetary heat sink, is the concept that the ocean is absorbing more heat to offset the increasing …

Nutrient Return To Soil In The Santa Monica Mountains After Combustion, Taylor Brooke Shapiro, Antonia Freund, Megan Chou

Featured Research

In this study, levels of phosphorus, nitrogen, and PH from eight uniform soil samples from the Santa Monica Mountain swere assessed. Our first testing group contained four uniform samples of soil, which were tested under regular drought conditions. Our second testing group contained four identical samples, which we tested under regular drought conditions and also exposed to fire. Our hypothesis was that soil after wildfire will have different amounts of phosphorous, nitrogen, and Ph. Our research found that average phosphorus uptake in unburned samples vs. burned samples were significantly different at a P<0.0001. Nitrogen and pH levels however, were not found significantly different between burned and unburned samples.

A Rare View Of Coding Mutations And Plasma Lipid Levels, Aniruddh Pradip Patel

Yale Medicine Thesis Digital Library

A RARE VIEW OF CODING MUTATIONS AND PLASMA LIPID LEVELS. Aniruddh P. Patel, Sekar Kathiresan. Center for Human Genetics Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA and Program in Medical and Population Genetics, the Broad Institute of Harvard and MIT, Cambridge, MA (Sponsored by Richard P. Lifton, Department of Genetics, Yale University School of Medicine, New Haven, CT).

Plasma low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) are quantitative, heritable risk factors for coronary heart disease. Genome-wide association screens (GWAS) of common DNA sequence variants have identified many loci associated with plasma lipid levels. Targeted …

The Role Of Platelets In Hyaluronan Degradation, Sami Albeiroti

ETD Archive

Following tissue injury, platelets rapidly interact with the exposed extracellular matrix (ECM) of blood vessel wall and the surrounding tissues. Hyaluronan (HA) is a major polysaccharide component of the ECM and plays a significant role in regulating inflammation. Human platelets can degrade HA from the surfaces of activated endothelial cells into fragments capable of inducing immune responses by monocytes. In addition, platelets contain the enzyme hyaluronidse-2 (HYAL2), one of two major hyaluronidases that digest HA in somatic tissues. The deposition of HA increases in the inflamed tissues in several inflammatory diseases, including Inflammatory Bowel Disease (IBD). This study provides evidence …

Ubiquitin-Proteasome System Modulates Platelet Function, Nilaksh Gupta

ETD Archive

Atherothrombotic diseases are responsible for more than 25 of all deaths worldwide. Anti-platelet drugs are the mainstay treatment because of the direct involvement of platelets in the initiation and propagation of thrombosis. However, the currently available anti-platelet drugs, such as antagonists of platelet receptors or of effector systems participating in platelet activation, have their own limitations. A new mode of affecting platelet reactivity may prove to offer unique advantages in a host of clinical settings. Proteasome inhibitors are in clinical use to treat hematologic cancers, but also reduce thrombosis. Whether the proteasome participates in platelet activation or function is opaque …

Acute And Chronic Rejection: Compartmentalization And Kinetics Ff Counterbalancing Signals In Cardiac Transplants, Anupurna Kaul

ETD Archive

Heart disease is the major cause of mortality in the United States and other parts of the world. Heart transplantation is the treatment of choice for patients with end stage heart failure. However, transplanted organs fail due to either acute or chronic rejection. This acute and chronic rejection impacts distinct compartments of cardiac allografts. Acute rejection is characterized by infiltration of mononuclear cells whereas chronic rejection is characterized by progressive narrowing of coronary arteries. In a minor histoincompatibility mismatch mouse model we found hearts transplanted from male to female C57BL/6 mice undergo an acute rejection with diffuse interstitial infiltrates at …

Trypanosoma Brucei Telomere Functions In Antigenic Variation, Unnati M. Pandya

ETD Archive

Trypanosoma brucei is a protozoan parasite that causes sleeping sickness in humans and Nagana in cattle. They evade the host's immune defense by periodically switching their major surface antigen, variant surface glycoprotein (VSG), a phenomenon termed antigenic variation. Inside its mammalian host, bloodstream form (BF) T. brucei monoallelically expresses its major surface molecule VSG from the VSG Expression Sites (ESs) located at subtelomeric loci. Monoallelic VSG expression ensures effective antigenic variation and maximizes the efficiency of T. brucei pathogenesis. In the mid-gut of its insect host (tsetse), procyclic form (PF) T. brucei expresses procyclins as the major surface molecules and …

Study Of Role Of Ribosomal Protein L13a In Resolving Inflammation, Darshana Poddar

ETD Archive

Inflammation is an obligatory attempt of the host immune system to protect the body against infection. However, unregulated synthesis of pro-inflammatory products can have detrimental effects. Though mechanisms which contribute to inflammation are well appreciated, those that resolve inflammation are poorly understood. Therefore, understanding the molecular basis of such pathways will provide an entirely novel approach to treat and prevent inflammatory diseases. Transcript-selective translational control can regulate the expression of a set of inflammatory genes. We have identified one such mechanism in a novel animal model which relies on the abrogation of ribosomal protein L13a-dependent translational silencing by creating macrophage-specific …

Role Of Mtorc1 And Autophagy In The Regulation Of Chemoresistance In Leukemic B-Cells, Arishya Sharma

ETD Archive

Deregulated mTORC1 contributes to tumorigenesis and chemoresistance. However, mTORC1-specific inhibitors (rapalogs) show modest efficacy in the clinic, as they unleash the feedback inhibition on upstream, prosurvival pathways. An alternative approach is to target downstream functions of mTORC1. We investigated acquired resistance to fludarabine (Flu), a purine analog, active agent for chronic lymphocytic leukemia (CLL). Elevated phospho-p70S6k (T389), an mTORC1 activation marker, predicted Flu resistance in a panel of B-cell tumor lines, and primary CLL cells. However, the rapalogs induced moderate cell death in Flu-resistant (FluR) and primary CLL cells. Activation of oncogenic pathways, including mTORC1, induces profound metabolic reprogramming to …

Analysis Of Copy Number Variation Association With Gwas Methylation Data, Jr., Steven Joseph Machusko

Theses & ETDs

This thesis examined whether CNVs have a statistically significant effect on the methylation status of a select group of genes previously found to have an association with lung cancer. Data from 1200 genotyped sputum samples from 1200 individuals of the Lovelace Smokers Cohort was analyzed to find the copy number variant composition of each sample. An association analysis between the found CNVs and data on each sample from a 12-gene methylation panel was then performed to determine any statistical significance between CNVs and the methylation phenotype. An ontology association analysis using the GREAT gene ontology tool was then performed on …

Drought-Induced Mortality In Malosma Iaurina And Ceanothus Megacarpus In Response To California's Changing Climate, Stefano Berrios, Stefani Francisco, Olivia Kim

Featured Research

The hypothesis of this research and experiment is that Malosma laurina is better adapted to drought than Ceanothus megacarpus due to its adaptation of deep roots. This addressed the question of which plants are better adapted to drought and by which adaptations are they superior. We decided to choose these two types of chaparral due to their differences in adaptations: Malosma laurina having deep roots and Ceanothus megacarpus utilizing cavitation resistance. Our method of investigation was to study the findings of scientific journal articles and to conduct our own experiment involving the mortality of Malosma laurina on the Pepperdine University …