Life Sciences Commons^™

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

Featured Research

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 …

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

Featured Research

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 …

Role Of Nucleation In Cortical Microtubule Array Organization: Variations On A Theme, Erica A. Fishel, Ram Dixit

Biology Faculty Research

The interphase cortical microtubules (CMTs) of plant cells form strikingly ordered arrays in the absence of a dedicated microtubule-organizing center. Considerable research effort has focused on activities such as bundling and severing that occur after CMT nucleation and are thought to be important for generating and maintaining ordered arrays. In this review, we focus on how nucleation affects CMT array organization. The bulk of CMTs are initiated from γ-tubulin-containing nucleation complexes localized to the lateral walls of pre-existing CMTs. These CMTs grow either at an acute angle or parallel to the pre-existing CMT. Although the impact of microtubule-dependent nucleation is …

Plant Cytoskeleton: Della Connects Gibberellins To Microtubules, Ram Dixit

Biology Faculty Research

A new study reveals that DELLA proteins directly interact with the prefoldin complex, thus regulating tubulin subunit availability in a gibberellin-dependent manner. This finding provides a mechanistic link between the growth-promoting plant hormone gibberellin and cortical microtubule organization.

Bromus Tectorum Litter Alters Photosynthetic Characteristics Of Biological Soil Crusts From A Semiarid Shrubland, Marcelo D. Serpe, Eric Roberts, David J. Eldridge, Roger Rosentreter

Biology Faculty Publications and Presentations

Invasion by the exotic annual grass Bromus tectorum has increased the cover and connectivity of fine litter in the sagebrush steppes of western North America. This litter tends to cover biological soil crusts, which could affect their metabolism and growth. To investigate this possible phenomenon, biological soil crusts dominated by either the moss Bryum argenteum or the lichen Diploschistes muscorum were covered with B.tectorum litter (litter treatment) or left uncovered (control treatment) and exposed to natural field conditions. After periods of five and ten months, we removed the litter and compared the photosynthetic performance of biological soil crusts …

Recent Characterizations Of Mscs And Its Homologs Provide Insight Into The Basis Of Ion Selectivity In Mechanosensitive Channels, Grigory Maksaev, Elizabeth S. Haswell

Biology Faculty Research

The bacterial mechanosensitive channel MscS provides an excellent model system for the study of mechanosensitivity and for investigations into the cellular response to hypoosmotic shock. Numerous studies have elucidated the structure, function and gating mechanism of Escherichia coli MscS, providing a wealth of information for the comparative analysis of MscS family members in bacteria, archaea, fungi and plants. We recently reported the electrophysiological characterization of MscS-Like (MSL)10, a MscS homolog from the model flowering plant Arabidopsis thaliana. Here we summarize our results and briefly compare MSL10 to previously described members of the MscS family. Finally, we comment on how …

The Varied Roles Of Induced Plant Responses In Species Interactions, Justine B. Roths Ms

All Student Scholarship

In this review, I will discuss indirect species interactions that occur as a result of herbivore-induced trait changes in plants. Species interactions are at the very core of the field of ecology. In particular, plant–insect herbivore interactions are of central importance as these two groups together consist of over 75% of the macroscopic diversity on earth. Historically, research has focused on pair-wise direct interactions however, more recently, the importance of indirect interactions has been widely acknowledged. Indeed, indirect interactions may be as strong and as common as direct interactions. Indirect interactions have been actively investigated in plant–insect systems, which are …

Warm Springs, Early Lay Dates, And Double Brooding In A North American Migratory Songbird, The Black-Throated Blue Warbler, Andrea K. Townsend, T. Scott Sillett, Nina K. Lany, Sara A. Kaiser, Nicholas L. Rodenhouse, Michael S. Webster, Richard T. Holmes

Dartmouth Scholarship

Numerous studies have correlated the advancement of lay date in birds with warming climate trends, yet the fitness effects associated with this phenological response have been examined in only a small number of species. Most of these species–primarily insectivorous cavity nesters in Europe–exhibit fitness declines associated with increasing asynchrony with prey. Here, we use 25 years of demographic data, collected from 1986 to 2010, to examine the effects of spring temperature on breeding initiation date, double brooding, and annual fecundity in a Nearctic - Neotropical migratory songbird, the black-throated blue warbler (Setophaga caerulescens). Data were collected from birds breeding at …

Using The Unispec To Test The Difference In Reflectance Of The Yellow Petals Of Encelia Californica, Encelia Farinosa, And Spartium Junceum, Mariam E. Fam, Valerie E. Espinoza

Featured Research

The reflectance spectrum of three yellow flowered species (Encelia californica, Encelia farinosa, and Spartium junceum), all grown on the coast of California, was tested to determine if reflectance among the yellow flowers was significantly different. It was hypothesized that there would be a significant difference in reflectance in the 400-700 nm wavebands for the three different species of flowers which all possess yellow petals. Using a Unispec Spectral Analysis System to obtain reflectance spectra for 12 yellow petals of three flowered species, a custom index was created in order to observe differences in the yellow color of the petals, which …

The Effects Of Leaf Hydration On Light Reflectance In Salvia Leucophylla And S. Mellifera, Logan A. Schmitz, Kolina Mah-Ginn, Hayley Presthus

Featured Research

The presence of trichomes on a plant affect the plant’s ability to retain water; this, in turn, must affect light propagation and reflectance. It was hypothesized that a plant with a higher trichome density (Salvia leucophylla) would have a greater change in reflectance when exposed to a more aired or hydrated environment than a species with a lower trichome density (S. mellifera). Results obtained using a Unispec suggest that Salvia mellifera is more resistant to change in NDVI in response to drying and wetting. Water potential data suggest this may be related to the plant’s resistance to actual drying and …

Fire Edge Effect On Water Potential And Stomatal Conductance In Salvia Leucophylla, Brigid N. Bergin, Paul Chung, Laura C. Miranda

Featured Research

While most plants caught in the middle of wildfires are completely incinerated, many in the edges survive despite suffering partial incineration and/or heat-induced damage. We hypothesized that heat damaged Salvia leucophylla will display a decrease in both stomatal conductance and water potential. We suspected that applying excess heat would lower the plant’s water levels and damage functional components necessary for photosynthesis, so the stomata would close to conserve water. S. leucophylla was chosen to study due to the likelihood of this widespread coastal sage to be found in the edges of wildfires in the Santa Monica Mountains. Using a heat …

Comparative Study Of The Mechanical Strength In Two Species Of Ferns: Polystichum Munitum And Pteridium Aquilinum, Russell P. Baetiong, Victoria M. Lekson, Olivier B. Monty

Featured Research

A comparative study of the mechanical strength in two species of ferns, the winter deciduous Pteridium aquilinum and the evergreen Polystichum munitum, was done. The mechanical strength of the leaf and stipe were used as a means for comparison. Additional data such as specific leaf mass (g/cm2) were also collected. The first hypothesis was that the evergreen fern would have higher leaf mechanical strength, while the second hypothesis was that there would be no difference in the mechanical strength of the stipe. The mechanical strength of the stipe was compared through the Modulus of Elasticity (MOE), while the leaf tensile …

Top And Bottom Photosynthetic Activity In Nerium Oleander And Pandanus Baptistii, Ryan Arima, Jacob Gonzalez

Featured Research

Photosynthesis can be performed on any part of a leaf, yet many plants orient their leaves in different ways and are composed of different leaf anatomies. In this experiment we attempted to discover if there is a significant difference between photosynthesis on the top and bottom of Nerium oleander, a dicot that orients its dorsal face towards the sun, and Pandanus baptistii, a monocot that does not orient its leaves specifically to the sun. To perform this experiment, we used both the LI-6400 and the LiCor Integrating Sphere. With the LI-6400, we measured the photosynthetic rate of the top and …

Mechanical Strength Comparison Of Hydrated And Dehydrated Pteridium Stems, Michelle I. Kang, Kevin M. Ko, John H. Noh, Veronica R. Vega

Featured Research

In this experiment, the mechanical strength of Pteridium stems was tested in two differing conditions: hydrated and dehydrated. It was hypothesized that there would be an increased performance of hydrated stems in the presence of mechanical stress. In order to test this hypothesis, twelve 20 cm pieces of stems were cut in alternation, separating those that would be dehydrated (6) with those that were hydrated (6). The dehydrated specimens were left to dry over a period of 24 hours. The diameters of each individual stem were measured to account for variation in size and remove excess variables. All twelve stems …

Using The Pace Eportfolio To Assess Core Values, Beth Klingner, Linda Anstendig, Sarah Burns-Feyl

Cornerstone 3 Reports : Interdisciplinary Informatics

No abstract provided.

Diagnosis And Prevention Of Metabolic Diseases In Drosophila Melanogaster, Claire Marie Coogan

Collection of Engaged Learning

No abstract provided.

Plant-Pollinator Interactions Over 120 Years: Loss Of Species, Co-Occurrence, And Function, Laura A. Burkle, John C. Marlin, Tiffany M. Knight

Biology Faculty Research

Using historic data sets, we quantified the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA. We found degradation of interaction network structure and function and extirpation of 50% of bee species. Network changes can be attributed to shifts in forb and bee phenologies resulting in temporal mismatches, nonrandom species extinctions, and loss of spatial co-occurrences between extant species in modified landscapes. Quantity and quality of pollination services have declined through time. The historic network showed flexibility in response to disturbance; however, our data suggest that networks will be …

Persons As Plants: Ecopsychology And The Return To The Dream Of Nature, Monica Gagliano

Landscapes: the Journal of the International Centre for Landscape and Language

Abstract. In this article, I examine human-plant perceptions and interactions in terms of developing a new perspective on the perception and the actions of people towards plants. By combining my scientific understanding of the biological world and my own experiences working with plant shamans, storytellers and mystics from around the world, I engage with the idea that the hierarchical structure by which Western science defines the variety of life forms as ‘primitive’ or ‘more evolved’ is at the root of the current environmental crisis and I argue that the solution to it rests in a change of this very perspective.

Under Graduate Curriculum Integration: Bringing Students Together Through Research, Clay Runck, James Russell, Allison D’Costa

Interdisciplinary STEM Teaching & Learning Conference (2012-2019) (Archived)

At Georgia Gwinnett College we are integrating the undergraduate educational experience for our Bachelor of Science students in the Biology discipline. We are using the opportunities presented by the genetic information revolution to combine biology courses in a longitudinal and integrative research project aimed at cataloguing biological diversity over space and time on the developing Georgia Gwinnett College campus.

Integrating Art And Science In Undergraduate Education, Daniel Gurnon

Chemistry & Biochemistry Faculty Publications

The prevailing vision for undergraduate science education includes increased collaboration among teachers of science, technology, engineering and math (STEM) and an overhaul of introductory courses [1]–[4]. But by staying within the borders of STEM, are we overlooking connections between the arts and innovative science? Likewise, are we missing an important opportunity to inspire and inform nonscientists? Here we explore how weaving the visual arts into a science curriculum can both help develop scientific imagination and engage nonscientists. As an example, we describe a recent collaboration between artists and scientists to create a series of science-inspired sculptures.

S-Adenosyl-L-Methionine Protects The Probiotic Yest, Saccharomyces Boulardii, From Acid-Induced Cell Death, Nicanor Austriaco, Vincent Cascio, Daniel Gittings, Kristen Merloni, David Laprade

Biology Faculty Publications

Background

Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract.

Results

We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we …

Dictyostelium Development Shows A Novel Pattern Of Evolutionary Conservation, Xiangjun Tian, Joan E. Strassmann, David C. Queller

Biology Faculty Research

von Baer's law states that early stages of animal development are the most conserved. More recent evidence supports a modified "hourglass" pattern in which an early but somewhat later stage is most conserved. Both patterns have been explained by the relative complexity of either temporal or spatial interactions; the greatest conservation and lowest evolvability occur at the time of the most complex interactions, because these cause larger effects that are harder for selection to alter. This general kind of explanation might apply universally across independent multicellular systems, as supported by the recent finding of the hourglass pattern in plants. We …

Regulation Of Antigenic Variation In Trypanosoma Brucei, Imaan A. Benmerzouga

ETD Archive

Trypanosoma brucei is a protozoan parasite that causes sleeping sickness in humans and nagana in cattle. When inside the mammalian host, T. brucei cells stay in extracellular spaces and regularly switch their surface antigen, Variant Surface Glycoprotein (VSG), to escape the host's immune responses. To ensure the effectiveness of VSG switching, T. brucei expresses a single type of VSG at any time exclusively from one of 20 identical VSG expression sites located next to the telomere. Monoallelic expression of VSG and VSG switching are important for T. brucei's pathogenesis. Our major goal is to understand the mechanisms of antigenic variation …

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

Featured Research

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 …

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

Featured Research

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. …

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

Featured Research

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.

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

Featured Research

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 …

Lifelines Winter 2013, Southern Adventist University

Lifelines - Biology Department Newsletter

The Winter 2013 issue of Lifelines features updates on research being conducted in the Biology Department, updates to the Biology Trail, student missions to Familia Feliz in Bolivia, and a pictorial directory of the 2013 biology and allied health graduates.

Bioinformatic Analysis And In Vitro Expression Of Malaria Parasite Translocon And Ribonuclease Binding-Like Rhoptry Genes, Moses Z. Timta

ETD Archive

Malaria caused by the parasite Plasmodium, still remains a significant public health problem worldwide, due to lack of a vaccine and emerging drug and insecticide resistance, among malaria parasites and mosquito vectors, respectively. Rhoptry proteins of Plasmodium enable merozoite invasion of host erythrocytes. However, only a few of these proteins have been characterized. Thirty-six P. yoelii merozoite rhoptry proteins were identified as putative rhoptry proteins by proteome analysis. Some of these proteins have been characterized while others still remain an intense area of active research. Molecular characterization and understanding of these novel proteins may assist in vaccine development, design of …

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

Featured Research

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 …