Biology Commons^™

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

Featured Research

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

Featured Research

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

Featured Research

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

Featured Research

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

Featured Research

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

Featured Research

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 …

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

Featured Research

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 …

Elevation’S Effect On Malosma Laurinais Leaf Size, Callyn E. Shelley, Nathan R. Gehring

Featured Research

Our hypothesis was that the average leaf size of Malosma laurinais would be different at high and low elevations due to the variance in temperature and solar radiation. This is especially relevant considering the severe drought conditions of California. Testing the factors of growth for chaparral may help ecologists to better understand how the plants cope with abnormalities in the ecosystem. Our study examined variance in Malosma laurinais leaf length, width, area, curvature, and thickness at high elevation (610 meters to 629 meters) and low elevation (27 meters to 53 meters) located along Sycamore Canyon. Differences were only significant in …

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

Featured Research

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

Featured Research

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.

The Mechanism Of Regulation Of Autosomal Heterochromatic Genes In Drosophila Melanogaster Males By Rox Rna And Msl Proteins, Satya Kiran Koya

Wayne State University Dissertations

In humans and flies, males and females have different set of sex chromosomes contributing to different levels of X-linked gene expression. To equalize X-linked gene dosage between sexes, both humans and flies developed independent strategies which are called dosage compensation. Human females randomly inactivate one of their X chromosome into barr body and Drosophila males up regulate their single X chromosome two fold. Both strategies equalize of X linked gene dose between sexes.

In Drosophila, dosage compensation is brought about by the ribonucleoprotein Male Specific Lethal (MSL) complex that binds hundreds of sites along the X chromosome and modifies …

Migratory Connectivity And Carry-Over Effects In Northwest Atlantic Loggerhead Turtles (Caretta Caretta, L.), Simona Ceriani

Electronic Theses and Dissertations

Migration is a widespread and complex phenomenon in nature that has fascinated humans for centuries. Connectivity among populations influences their demographics, genetic structure and response to environmental change. Here, I used the loggerhead turtle (Caretta caretta, L.) as a study organism to address questions related to migratory connectivity and carry-over effects using satellite telemetry, stable isotope analysis and GIS interpolation methods. Telemetry identified foraging areas previously overlooked for loggerheads nesting in Florida. Next, I validated and evaluated the efficacy of intrinsic markers as a complementary and low cost tool to assign loggerhead foraging regions in the Northwest Atlantic Ocean (NWA), …

Bacon's Swamp- Ghost Of A Central Indiana Natural Area Past, Rebecca W. Dolan

Scholarship and Professional Work - LAS

Bacon’s Swamp was identified in the 1920s as a ca. 12 ha glacial kettle lake bog system at the southernmost limits of these habitats in Indiana. Located just 9.6 km from the center of Indianapolis, the site was all but destroyed in the mid-20th century by urban expansion. Prior to habitat conversion at the site, Bacon’s Swamp was a frequent location for Butler University ecology class field trips and student research projects. Herbarium specimens and published inventory records allow for analysis of the historical vegetation of Bacon’s Swamp using modern techniques. Floristic Quality Assessment applied to these historical records reveals …

Nitrogen Fertilization Has A Stronger Effect On Soil Nitrogen-Fixing Bacterial Communities Than Elevated Atmospheric Co2, Sean T. Berthrong, Chris M. Yeager, Laverne Gallegos-Graves, Blaire Steven, Stephanie A. Eichorst, Robert B. Jackson, Cheryl R. Kuske

Scholarship and Professional Work - LAS

Biological nitrogen fixation is the primary supply of N to most ecosystems, yet there is considerable uncertainty about how N-fixing bacteria will respond to global change factors such as increasing atmospheric CO₂ and N deposition. Using the nifH gene as a molecular marker, we studied how the community structure of N-fixing soil bacteria from temperate pine, aspen, and sweet gum stands and a brackish tidal marsh responded to multiyear elevated CO₂ conditions. We also examined how N availability, specifically, N fertilization, interacted with elevated CO₂ to affect these communities in the temperate pine forest. Based on data …

Did Androgen-Binding Protein Paralogs Undergo Neo- And/Or Subfunctionalization As The Abp Gene Region Expanded In The Mouse Genome?, Robert C. Karn, Amanda G. Chung, Christina M. Laukaitis

Scholarship and Professional Work - LAS

The Androgen-binding protein (Abp) region of the mouse genome contains 30 Abpa genes encoding alpha subunits and 34 Abpbg genes encoding betagamma subunits, their products forming dimers composed of an alpha and a betagamma subunit. We endeavored to determine how many Abp genes are expressed as proteins in tears and saliva, and as transcripts in the exocrine glands producing them. Using standard PCR, we amplified Abp transcripts from cDNA libraries of C57BL/6 mice and found fifteen Abp gene transcripts in the lacrimal gland and five in the submandibular gland. Proteomic analyses identified proteins corresponding to eleven of the …

Progress Towards A Molecular Phylogeny Of Tachinidae, Year Two, Isaac S. Winkler, John O. Stireman Iii, John K. Moulton, Pierfilippo Cerretti, Jeremy D. Blaschke

Biological Sciences Faculty Publications

We reported last year (Stireman et al. 2013) in The Tachinid Times on our collaborative project, funded by the U.S. National Science Foundation, to study the phylogeny of Tachinidae on a worldwide scale. Since that report, we have made some significant progress towards our goal of assembling a robust phylogenetic tree for Tachinidae. Notably, Cerretti et al. (in press) completed a phylogenetic study using 135 morphological characters from 180 tachinid genera. Results from this study largely reflect, with some interesting exceptions, what we are finding from preliminary analyses of our molecular data. Although sampling of taxa and genes for the …

Changes In Gene Expression And Viral Titer In Varroa Jacobsoni Mites After A Host Shift Asian To European Honey Bees, Gladys K. Andino Bautista

Open Access Dissertations

Honey bees (Apis mellifera L.) are the most important insects for the pollination of crops and wildflowers. However, they have experienced increasing colony die-offs during the past two decades. Multiple species of parasitic mites have been described that affect honey bees. The most important species in beekeeping belong to the genus Varroa ( Varroa jacobsoniand Varroa destructor). Varroa mite parasitism of honey bees is thought to be the most significant cause of colony mortality worldwide, and mite resistance to active ingredients of acaricides has become common. V. destructor causes direct impacts on bee production as well as …

Upregulation Of Functional Kv11.1 Isoform Expression By Inhibition Of Intronic Polyadenylation With Antisense Morpholino Oligonucleotides, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The KCNH2 gene encodes the Kv11.1 potassium channel that conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative processing; intron 9 splicing leads to the formation of a functional, full-length Kv11.1a isoform, while polyadenylationwithin intron 9 generates a non-functional, Cterminally truncated Kv11.1a-USO isoform. The relative expression of Kv11.1 isoforms plays an important role in the regulation of Kv11.1 channel function and the pathogenesis of long QT syndrome. In this study,we identified cis-acting elements that are required for KCNH2 intron 9 poly(A) signal activity. Mutation of these elements decreased Kv11.1a-USO expression and increased the expression of …

Antipredator Behavior In Desmognathus Ochrophaeus: Threat-Specific Responses To Chemical Stimuli In A Foraging Context, Elyse C. Johnson, Aaron M. Sullivan

Faculty Publications - Department of Biological & Molecular Science

Prey species may reduce the likelihood of injury or death by engaging in defensive behavior but often incur costs related to decreased foraging success or efficiency. To lessen these costs, prey may adjust the intensity or type of antipredator behavior according to the nature of the perceived threat. We evaluated the potential for threat-sensitive responses by Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus) exposed to chemical stimuli associated with predation by asking three questions:(1) Do individual D. ochrophaeus respond to chemical cues in a threat-sensitive manner? (2) Do salamanders exhibit the same pattern of behavioral response while foraging? and (3) Is …

Regulation Of Lncap Respiration By Plasma Membrane And Mitochondrial Angiotensin Ii Receptors (1159.11), Jeff Duerr, Anna Reister

Faculty Publications - Department of Biological & Molecular Science

Prostate cancer is diagnosed in over 186,000 men in the United States and accounts for more than 28,000 deaths annually. Angiotensin II (AngII) is a major effector peptide of the renin-angiotensin system (RAS), and is an important factor in hypertension. Correlations between ACE therapy and improved prostate cancer outcomes led to in vitro studies the action of AngII in cultured prostate cancer cell lines. Investigators have reported that exogenous application of Ang II to LNCaP cells results in the activation of Akt signaling, increased activity of SOD, and glutathione peroxidase. As the mitochondrion is a major contributor of total cellular …

Modulation Of Innate Immunity In Arabidopsis, Shweta Panchal

Biology Dissertations - Archive

Plants possess a highly sophisticated defense system to fight against pathogen infection. One of the components of this system, stomatal immunity, was studied here. Stomata, formed by a pair of epidermal guard cells, are tiny apertures on leaf surfaces that regulate exchange of gases and water loss in the plant. Apart from this function, stomata actively close in response to pathogens, thereby preventing entry of the pathogen in the plant. This constitutes stomatal immunity. However, in this study it was seen that stomatal immunity in Arabidopsis thaliana is suppressed when infection occurs in high relative humidity (RH). Now, opening and …

Evolution Of Sex Ratios And Sex Determination Mechanisms: Lessons From Nematodes With Three Genders, Manish Parihar

Biology Dissertations - Archive

In sexually reproducing species, the decision to allocate resources towards male and female reproductive function is called sex allocation. Although theoretical and empirical work has been largely successful, the underlying mechanisms of sex allocation are not very well known. For instance, little is known about how the parents adjust the sex of the offspring in response to specific environmental conditions. According to Mendel's law of segregation, in species that have two genders, a cross between the male and the female should give an equal proportion of male and female progeny. However, there are some species that deviate from this genetic …

Seasonal And Habitat-Based Prey Diversity Of Bobcats, Lynx Rufus, In Big Bend National Park, Texas, Ellen Stringer Browning

Biology Dissertations - Archive

The bobcat (Lynx rufus) population in Big Bend National Park (BIBE) provides an excellent opportunity for study due to the varied arid habitat in which they exist, the dynamic nature of their environment, and the paucity of scientific documentation on this unexploited population. As an abundant carnivore, the bobcat is crucial to BIBE's community ecology and trophic structure, emphasizing the need to investigate, in depth food habits in relation to environmental factors. Bobcats feed on a variety of small vertebrates, primarily lagomorphs and rodents, and are also known to take down large prey, such as mule deer and white tailed …

Individual Phenotypic Variation Reduces Interaction Strengths In A Consumer–Resource System, Jean P. Gibert, Chad Brassil

School of Biological Sciences: Faculty Publications

Natural populations often show variation in traits that can affect the strength of interspecific interactions. Interaction strengths in turn influence the fate of pairwise interacting populations and the stability of food webs. Understanding the mechanisms relating individual phenotypic variation to interaction strengths is thus central to assess how trait variation affects population and community dynamics. We incorporated nonheritable variation in attack rates and handling times into a classical consumer–resource model to investigate how variation may alter interaction strengths, population dynamics, species persistence, and invasiveness. We found that individual variation influences species persistence through its effect on interaction strengths. In many …

Comparison Of The Wing Polyphenic Response Of Pea Aphids (Acyrthosiphon Pisum) To Crowding And Predator Cues, Swapna R. Purandare, Brigitte Tenhumberg, Jennifer A. Brisson

School of Biological Sciences: Faculty Publications

1. Pea aphids (Acyrthosiphon pisum Harris; Hemiptera: Aphididae) exhibit transgenerational wing polyphenism, in which unwinged females produce genetically identical winged offspring in response to environmental cues such as overcrowding and predation risk that indicate poor habitat quality.

2. Laboratory experiments were carried out to explore the intensity of the wing polyphenic response of pea aphids exposed to cues from ladybird predators and crowding, and their response was compared to pea aphids that were not exposed to any cues (control).

3. The study used cues from two different ladybird species: Coccinella septempunctata L. (Coleoptera: Coccinellidae) and Hippodamia convergens Guérin-Méneville (Coleoptera: …

Immunity Of The Saccharomyces Cerevisiae Ssy5 Mrna To Nonsense-Mediated Mrna Decay, Jesseeca Obenoskey, Dakota R. Lane, Audrey L. Atkin, Bessie W. Kebaara

School of Biological Sciences: Faculty Publications

The nonsense-mediated mRNA decay (NMD) pathway is a specialized pathway that triggers the rapid degradation of select mRNAs. Initially, identified as a pathway that degrades mRNAs with premature termination codons, NMD is now recognized as a pathway that also regulates some natural mRNAs. Since natural mRNAs do not typically contain premature termination codons, these mRNAs contain features that target them to NMD. In Saccharomyces cerevisiae mRNAs with a typically long 3’UTRs are usually degraded by NMD, however in some conditions a constitutively expressed SSY5 mRNA with multiple NMD targeting signals including an atypically long 3’-UTR is an exception. We investigated …

Role Of An Archaeal Pita Transporter In The Copper And Arsenic Resistance Of Metallosphaera Sedula, An Extreme Thermoacidophile, Samuel Mccarthy, Chenbing Al, Garrett Wheaton, Rahul Tevatla, Valerie Eckrich, Robert Kelly, Paul H. Blum

School of Biological Sciences: Faculty Publications

Thermoacidophilic archaea, such as Metallosphaera sedula, are lithoautotrophs that occupy metal-rich environments. In previous studies, an M. sedula mutant lacking the primary copper efflux transporter, CopA, became copper sensitive. In contrast, the basis for supranormal copper resistance remained unclear in the spontaneous M. sedula mutant, CuR1. Here, transcriptomic

analysis of copper-shocked cultures indicated that CuR1 had a unique regulatory response to metal challenge corresponding to the upregulation of 55 genes. Genome resequencing identified 17 confirmed mutations unique to CuR1 that were likely to change gene function. Of these, 12 mapped to genes with annotated function associated with transcription, metabolism, …

Identification And Codon Reading Properties Of 5-Cyanomethyl Uridine, A New Modified Nucleoside Found In The Anticodon Wobble Position Of Mutant Haloarchaeal Isoleucine Trnas, Debabrata Mandal, Caroline Köhrer, Dan Su, Ramesh Babu, Clement T.Y. Chan, Yuchen Liu, Dieter Söll, Paul H. Blum, Masayasu Kuwahara, Peter C. Dedon, Uttam L. Rajbhandary

School of Biological Sciences: Faculty Publications

Most archaea and bacteria use a modified C in the anticodon wobble position of isoleucine tRNA to base pair with A but not with G of the mRNA. This allows the tRNA to read the isoleucine codon AUA without also reading the methionine codon AUG. To understand why a modified C, and not U or modified U, is used to base pair with A, we mutated the C34 in the anticodon of Haloarcula marismortui isoleucine tRNA (tRNA₂^Ile) to U, expressed the mutant tRNA in Haloferax volcanii, and purified and analyzed the tRNA. Ribosome binding experiments show that …

Different Gene-Specific Mechanisms Determine The ‘Revised-Response’ Memory Transcription Patterns Of A Subset Of A. Thaliana Dehydration Stress Responding Genes, Ning Liu, Yong Ding, Michael Fromm, Zoya Avramova

School of Biological Sciences: Faculty Publications

Plants that have experienced several exposures to

dehydration stress show increased resistance to future

exposures by producing faster and/or stronger

reactions, while many dehydration stress responding

genes in Arabidopsis thaliana super-induce their

transcription as a ‘memory’ from the previous encounter.

A previously unknown, rather unusual,

memory response pattern is displayed by a subset

of the dehydration stress response genes. Despite

robustly responding to a first stress, these genes

return to their initial, pre-stressed, transcript levels

during the watered recovery; surprisingly, they do

not respond further to subsequent stresses of similar

magnitude and duration. This transcriptional behavior

defines the …

H3k27me3 And H3k4me3 Chromatin Environment At Super-Induced Dehydration Stress Memory Genes Of Arabidopsis Thaliana, Ning Liu, Zoya Avramova, Michael Fromm

School of Biological Sciences: Faculty Publications

Pre-exposure to a stress may alter the plant’s cellular, biochemical, and/or transcriptional responses during future encounters as a “memory” from the previous stress. Genes increasing transcription in response to a first dehydration stress, but producing much higher transcript levels in a subsequent stress, represent the super-induced “transcription memory” genes in Arabidopsis thaliana. The chromatin environment (histone H3 tri-methylations of Lys 4 and Lys 27, H3K4me3, and H3K27me3) studied at five dehydration stress memory genes revealed existence of distinct memory-response subclasses that responded differently to CLF deficiency and displayed different transcriptional activities during the watered recovery periods. Among the most …