Biology Commons^™

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) …

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 …

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

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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 …

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 …

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

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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 …

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 …

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

Featured Research

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. …