Biology Commons^™

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) …

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

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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 …

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 …

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 …

Assessment Of P38 And Extracellular Signal-Regulated Kinase (Erk) In Regulating Apoptosis During Low And High Er Stress, Zachary G. Coffman

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The endoplasmic reticulum (ER) is an important organelle within the cell that has many functions including protein folding. When the protein folding capabilities of the ER are compromised ER stress occurs. Extracellular signal-regulated kinases (ERKs) and p38 are MAP kinases that are induced as a result of ER stress. ERK is a protein that has been associated with cell proliferation and survival while p38 is a protein that has been associated with apoptosis, which is programmed cell death. The objective of this study was to measure ERK and p38 induction over time during low and high ER stress. Another objective …

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 …

Flow-Induced Dilation Of Skeletal Muscle Feed Arteries: Relevance To Exercise Hyperemia, Brittni M. Moore, Jeffrey L. Jasperse

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During exercise, an increase in blood flow to working skeletal muscle is accomplished by dilation of arteries and arterioles supplying the muscle. Arterioles, located within contracting muscle, are exposed to dilatory metabolites released by the muscle; however, the mechanism by which feed arteries, located external to the muscle, dilate is still unknown.

One potential mechanism for feed artery dilation is flow-induced dilation, occurring when arteries dilate in response to increased vascular wall shear stress. Shear stress is the frictional force between blood and the arterial wall, which increases when blood flow velocity increases. Data from previous in vitro experiments (8) …

Foliar Water Uptake And Resurrection: Mechanisms Of Drought Tolerance In Eight Species Of Ferns In The Santa Monica Mountains, Victoria M. Lekson

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In a region where drought is severe, ecological surveys provide insight into the adaptations of organisms living on the edge of survival. In this study, the mechanisms of drought tolerance for eight species of ferns in the Santa Monica Mountains were assessed with a focus on foliar water uptake and resurrection strategies. We find that species are significantly different (P < 0.001) in their ability to absorb water through leaves (assessed gravimetrically) and correlate this to minimum seasonal water potential and hydrophobicity of leaf surfaces. Secondly, we irrigated Pentagramma triangularis in the field and tracked chloroplast recovery. We found possible evidence of embolism reversal. Taken together, this study explored the methods of survival of the most ancient family of vascular plants.

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. …