Biology Commons^™

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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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.

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 …

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

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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 …

Comparison Of Downstream Cell Survival Responses In Huvecs And Hlecs During Vegf Signaling, Haley M. Smith, Thomas Vandergon

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Angiogenesis and lymphangiogenesis are vital processes that allow the formation of new blood and lymph vessels from existing vessels to bring oxygen and vital nutrients to the body. These processes occur through Vascular Endothelial Growth Factor (VEGF) signaling to vascular endothelial cells where they bind to cell surface receptors. There are a variety of responses to these signals including cell proliferation, migration and survival. In this study Human Umbilical Vascular Endothelial Cells (HUVECs) and Human Lymphatic Endothelial Cells (HLECs) were stressed with Tunicamycin and supplemented with various VEGF signals to examine how cell survival pathways might respond during VEGF signaling. …

Reduced Ability Of Drought-Effected Plants To Assimilate Carbon Dioxide, Adrian Alvarado, Francisco De Mendiola, Julia Namkoong, Yunni Zhai

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As a group, we hypothesized that plants affected by the drought will absorb less CO2 compared to those that are irrigated regularly by Pepperdine University. In order to test this out we used the Carbon Dioxide CO2 transmitter which analyzed the carbon dioxide levels and conduction of three leaves that are under the drought and three leaves that are fully irrigated. The results were outstanding. As we hypothesized, the irrigated leaves had significantly higher CO2 and photosynthesis values than the leaves that were in the drought. The results are clearly reflected in the data, and consistent with the initial hypothesis. …

What You Can Do About The Negative Effects Of Methane, Jb Maza, Laurel Rodewald, Ashley Thurmond

Featured Research

Our central objective was to investigate the apparent rise in methane emissions and whether or not they are having a negative effect on the environment. By themselves, methane emissions are natural and self-regulating (and thus do not cause damage to the atmosphere), but our thesis is that a build up of methane emissions as a result of increased human activity/negligence poses a threat to the environment, and needs to be addressed in the quest to live sustainably. In our research, we chose to focus specifically on one source of methane emissions: permafrost, both because there is a significant amount of …

Initial Post-Fire Resprout Success Of Q. Agrifolia, J. Californica, And P. Racemosa In Sycamore Canyon, Frida Morales, Sawyer Mcgale, Drew Bowers, Zahra Madraswala, Michael Mori

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Resprouting after fire and during a drought can be one of the greatest challenges a plant faces. This phenomena was observed and recorded in three different species of trees: P. racemosa, Q. agrifolia, and J. californica, all located in the Sycamore Canyon study site in Pt. Mugu State Park. P. racemosa was hypothesized to initially be the most successful post fire resprouter. The rationale for this is that the DBH and deciduous factor would cause the tree's vascular system to survive and possess usable starches to power resprouting. The data was analyzed and found to support the hypothesis.

Community Structure And Differential Mortality Of Chaparral During Extreme Drought, Keb Doak, Allison Hubbard, Alawna Jamison

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We have set out to find, in extreme drought, which species of chaparral are dominant and why they are dominating. We thought that the indicator species of chaparral, Adenostoma fasciculatum, would have highest relative density, relative frequency, and dominance in our research area. Additionally, plants with higher water potential values would have lower percentages of mortality. Chaparral with stronger ability to fluoresce (higher Fv/Fm value) would have lower mortality percentages due to their ability to dissipate excess energy, and therefore reduce water loss. By analyzing our vegetation area using point-quarter sampling system, we were able to record data that show …

Effects Of Personal Gardens On The Reduction Of Atmospheric Co2 And Climate Change, Jacqueline N. Brody, Paige L. Elson, Brittany V. New

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This study aims to explore the long-term benefits of home gardening if every student at Pepperdine were to hypothetically sustain their own home garden in the state of California and the effect that this would have on state carbon absorption as a means of decreasing atmospheric CO2 and reducing further climate change.

Measuring Performance Of A Weedy Species (Nicotania Glauca) Vs. A Native Species (Venegasia Carpesioides) On The Pepperdine Campus, Emily J. Blair, Zach G. Coffman, Celina Y. Jones

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This study investigated four different mechanisms of growth performance of a native chaparral species, Venegasia carpesioides, and a weedy species, Nicotiana glauca. The research group hypothesized that one or more of the following variables would be higher for the weedy species than the native species: photosynthetic rate, conductance, fluorescence, and electron transport rate (ETR). This hypothesis was formulated in order to provide a plausible explanation for why weedy species often outcompete native species when grown in proximity to each other, especially in a chaparral environment experiencing drought conditions. This hypothesis was tested by obtaining two groups of each species and …

Water Analysis Of The Malibu Lagoon And Pacific Ocean, Emily E. K. Kelly, Jillian S. Unruh, Maxwell K. Gamboa

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This experiment tested the waters of the Malibu Lagoon and the Pacific ocean to compare levels of E.coli. We hypothesized that greater amount of E.coli would be present in the waters of the Malibu Lagoon. Because of the runoff and pollution existing in the lagoon, we predicted that higher levels of this bacteria would be found there. This study is significant because many organisms living in these waters can be negatively effected by large levels of E.coli. We used the most probable number method to determine the amounts of bacteria. A collection of samples from three testing sites in both …

Climate Change And Drought In California, Jake Szarzynski, Wei Zhang, Brennan Tatem

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we believe that there is a correlation between the increasing frequency and duration of droughts in California and climate change. The first step to solving any problem, such as a drought, is to identify the cause of the problem. As a result of the research conducted, we can determine that it is possible that climate change is a leading cause to droughts. We hope that by providing evidence that climate change is causing droughts, people will become aware that climate change does have negative results that we experience on a daily basis. We used several different scholarly resources when conducting …

Coreopsis Gigantea And Ice Plant Relationship On Point Dume, Lizzie Fichtner, Mccartney Ruff, Sean Hanson

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This study looks to determine the affects of the non-native ice plant on the native Coreopsis gigantea located at Point Dume in Malibu, California. After examining the size of the Coreopsis we were able to identify that they were smaller in height when growing next to the ice plant and greater height when farther away. We concluded that the Coreopsis does survive next to the ice plant, however its growth is restricted. Through our research we discovered many factors that could attribute to the growth difference, yet further research is necessary to decipher the main one.

Post-Fire Recovery Of Juglans Californica In Sycamore Canyon: Gas Exchange Performance Of Unburned Mature And Burned Epicormic And Basal Resprouts, Taylor Stucky, Gabby Gurule-Small

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Sycamore Canyon experienced a fire during April of 2013. This allowed for the comparison of burned and unburned individuals in the area. Based on its resprouting types and abundance in the area, Juglans californica made for a good test species. A total of eighteen individuals were tagged and used with a LiCor6400-XT to find fluorescence, Jmax, Vcmax, TPU, gm, photosynthesis, and conductance. Leaf samples were sent to California State University, Bakersfield for Nitrogen analysis to obtain PPNUE and percent nitrogen (with specific leaf area). These data were compared between unburned mature, and burned basal and epicormic resprouts. ANOVA testing established …

Seedling Survival After Novel Drought-Induced Germination In Ceanothus Megacarpus, Amanda M. Burns

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As California is experiencing what is believed to be the worst drought in 500 years, monitoring the change of vegetation is of utmost importance. This spring we observed novel germination of Big Pod Ceanothus seedlings (Ceanothus megacarpus). Germination was novel in that seeds typically require a fire heat cue but in this particular case, germination was likely due to excessive soil temperatures resulting from drought-induced canopy reduction. This is a phenomenon not well known to science as Ceanothus megacarpus seedlings are typically not found between fire events. We believe this results from increased soil temperatures due to greater openings in …