Biology Commons^™

Genomic Gc Content Drifts Downward In Most Bacterial Genomes, Ely Bert

Faculty Publications

In every kingdom of life, GC->AT transitions occur more frequently than any other type of mutation due to the spontaneous deamination of cytidine. In eukaryotic genomes, this slow loss of GC base pairs is counteracted by biased gene conversion which increases genomic GC content as part of the recombination process. However, this type of biased gene conversion has not been observed in bacterial genomes, so we hypothesized that GC->AT transitions cause a reduction of genomic GC content in prokaryotic genomes on an evolutionary time scale. To test this hypothesis, we used a phylogenetic approach to analyze triplets of …

Hdac6 Inhibitors Sensitize Non-Mesenchymal Triple-Negative Breast Cancer Cells To Cysteine Deprivation, Tahiyat Alothaim, Morgan Charbonneau, Xiaohu Tang

Michigan Tech Publications, Part 1

Triple-negative breast cancer (TNBC) is a highly malignant type of breast cancer and lacks effective therapy. Targeting cysteine-dependence is an emerging strategy to treat the mesenchymal TNBC. However, many TNBC cells are non-mesenchymal and unresponsive to cysteine deprivation. To overcome such resistance, three selective HDAC6 inhibitors (Tubacin, CAY10603, and Tubastatin A), identified by epigenetic compound library screening, can synergize with cysteine deprivation to induce cell death in the non-mesenchymal TNBC. Despite the efficacy of HDAC6 inhibitor, knockout of HDAC6 did not mimic the synthetic lethality induced by its inhibitors, indicating that HDAC6 is not the actual target of HDAC6 inhibitor …

Genomic Gc Content Drifts Downward In Most Bacterial Genomes, Bert Ely

Faculty Publications

In every kingdom of life, GC->AT transitions occur more frequently than any other type of mutation due to the spontaneous deamination of cytidine. In eukaryotic genomes, this slow loss of GC base pairs is counteracted by biased gene conversion which increases genomic GC content as part of the recombination process. However, this type of biased gene conversion has not been observed in bacterial genomes, so we hypothesized that GC->AT transitions cause a reduction of genomic GC content in prokaryotic genomes on an evolutionary time scale. To test this hypothesis, we used a phylogenetic approach to analyze triplets of …

Analysis Of Symptom Expressions And Transmission Rates Caused By The Plant Pathogen Phytophthora Ramorum On Native Chaparral Plants From The Genus Arctostaphylos, Bharati Gaonker

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Phytophthora ramorum is the causal agent of Sudden Oak death (SOD), ramorum dieback and ramorum leaf blight which affect both forest environments and nurseries. This oomycete pathogen has had a huge economic impact on the nursery and lumber industry. Forests in California have experienced substantial mortality of oaks affecting the forest dynamics and diversity. Our research investigates four native species and two ornamental cultivars of plants, which belong to the genus Arctostaphylos (manzanita) and are considered to be new hosts for P. ramorum in the chaparral ecosystem of California. Symptom expression and transmission rates were analyzed on Arctostaphylos glauca, …

Phantom Rivers Filter Birds And Bats By Acoustic Niche, D. G. E. Gomes, C. A. Toth, H. J. Cole, C. D. Francis, J. R. Barber

Biology Faculty Publications and Presentations

Natural sensory environments, despite strong potential for structuring systems, have been neglected in ecological theory. Here, we test the hypothesis that intense natural acoustic environments shape animal distributions and behavior by broadcasting whitewater river noise in montane riparian zones for two summers. Additionally, we use spectrally-altered river noise to explicitly test the effects of masking as a mechanism driving patterns. Using data from abundance and activity surveys across 60 locations, over two full breeding seasons, we find that both birds and bats avoid areas with high sound levels, while birds avoid frequencies that overlap with birdsong, and bats avoid higher …

Characterizing The Gene Regulatory Network Required To Specify The Excitatory Neurotransmitter Phenotype Of V0v Spinal Interneurons, Amber Kellie Woodard

Theses - ALL

The majority of neurons within the spinal cord are interneurons. Interneurons make important connections with other cells that allow signals to be relayed between the brain and the rest of the body, and aid in functions such as locomotion. One key functional characteristic of interneurons is the neurotransmitter that they use to communicate with other cells. Interneurons that use GABA or glycine neurotransmitters to communicate have an inhibitory phenotype, while interneurons that use glutamate neurotransmitters have an excitatory neurotransmitter phenotype. Without the correct neurotransmitter phenotype, connections within the central nervous system will malfunction. It is therefore important to understand how …

Characterizing The Gene Regulatory Network Required To Specify The Excitatory Neurotransmitter Phenotype Of V0v Spinal Interneurons, Amber Kellie Woodard

Theses - ALL

The majority of neurons within the spinal cord are interneurons. Interneurons make important connections with other cells that allow signals to be relayed between the brain and the rest of the body, and aid in functions such as locomotion. One key functional characteristic of interneurons is the neurotransmitter that they use to communicate with other cells. Interneurons that use GABA or glycine neurotransmitters to communicate have an inhibitory phenotype, while interneurons that use glutamate neurotransmitters have an excitatory neurotransmitter phenotype. Without the correct neurotransmitter phenotype, connections within the central nervous system will malfunction. It is therefore important to understand how …

Androgen Receptor, Although Not A Specific Marker For, Is A Novel Target To Suppress Glioma Stem Cells As A Therapeutic Strategy For Glioblastoma, Nan Zhao, Fei Wang, Shaheen Ahmed, Kan Liu, Chi Zhang, Sahara J. Cathcart, Dominick J. Dimaio, Michael Punsoni, Bingjie Guan, Ping Zhou, Shuo Wang, Surinder K. Batra, Tatiana Bronich, Tom K. Hei, Chi Lin, Chi Zhang

School of Biological Sciences: Faculty Publications

Targeting androgen receptor (AR) has been shown to be promising in treating glioblastoma (GBM) in cell culture and flank implant models but the mechanisms remain unclear. AR antagonists including enzalutamide are available for treating prostate cancer patients in clinic and can pass the blood–brain barrier, thus are potentially good candidates for GBM treatment but have not been tested in GBM orthotopically. Our current studies confirmed that in patients, a majority of GBM tumors overexpress AR in both genders. Enzalutamide inhibited the proliferation of GBM cells both in vitro and in vivo. Although confocal microscopy demonstrated that AR is expressed but …

Construction Of Dichotomous Taxonomic Keys For San Francisco Bay Planktonic Diatoms, Ria Angelica Laxa

Undergraduate Honors Theses

Planktonic diatoms exhibit high biodiversity in marine systems and make a significant contribution to water column primary productivity. This makes research on planktonic diatoms particularly important in measuring the health of coastal marine ecosystems. At the University of San Francisco (USF), undergraduate research has been conducted since September 2015 to study planktonic diatoms in San Francisco Bay. A previous study by Keith (2018), Planktonic Diatom Species Succession in San Francisco Bay, documented changes in species diversity over time, observing seasonal patterns in species richness as well as the effect of environmental factors such as salinity, temperature, and rainfall on species …

Acetaminophen Potentiates Fear Processing: A Comparison Between Ancestral And Modern Threats, Andrew Gallup, Brianda Gagnon, Gillian Perry, Omar T. Eldakar

Biology Faculty Articles

The painkilling medication acetaminophen produces a variety of unintended psychological effects. In particular, it has been shown to diminish varied forms of psychological distress by attenuating neural activity in the cerebral cortex and enhancing the signaling of serotonin. As a result, this over-the-counter medication appears to dampen overall affective processing and has been termed “an all-purpose emotion reliever.” However, this drug may not necessarily modify all emotions in the same manner. Specifically, fear processing occurs rapidly within the amygdala and is governed by serotonin. Thus, by blunting cortical activity and facilitating serotonergic action, acetaminophen could in fact potentiate reactions to …

Effects Of Covid-19 On Global Healthcare Research And Management, Stephanie Autore, Santanu De

Biology Faculty Articles

The Coronavirus Infectious Disease 2019 (COVID-19) pandemic has affected most nations at all levels of functioning, individual to governmental. Therefore, it is imperative to evaluate the effects the virus has had on one of the most important socioeconomic global sectors – healthcare. This comprehensive literature review explores key, recent research and management strategies that have been undertaken in healthcare systems around the world in order to make meaningful attempts at identifying the etiology, diagnosis, and treatment the disease, and combating the spread of this deadly virus. Healthcare facilities have implemented a variety of changes, all geared towards reducing non-emergency patient …

Evidence For Perchlorate-Coupled Molybdenum And Nickel Carbon Monoxide Dehydrogenase Co Oxidation And Characterization Of Novel Perchlorate-Reducing Haloarchaea, Marisa Russell Myers

LSU Doctoral Dissertations

Carbon monoxide (CO) has been exploited as a microbial energy source for much of life’s evolutionary history. A phylogenetically diverse array of microorganisms can oxidize CO using two distinct CO dehydrogenases, molybdenum-dependent (Mo-CODH) and nickel-dependent (Ni-CODH). Aerobes and facultative organisms contain Mo-CODHs which allow them to utilize oxygen as an electron acceptor in addition to alternatives such as nitrate and sulfate. Obligate anaerobic organisms contain Ni-CODHs, which oxidize CO at elevated concentrations, but cannot utilize oxygen. In systems where organic matter deposits are limited or absent, atmospheric trace gases such as CO are thought to assist in supporting the growth …

The Chemistry Of Fermentation As It Relates To The Art Of Winemaking, Olivia Cochran

Symposium of Student Scholars

The process of fermentation can be traced back to the beginning of civilization. Countries, over time, have learned this scientific process and turned it into the backbone of their culture through the making and manufacturing of wine. While climate-change and global-warming have impacted the commercial marketability of wine, the scientific process has remained constant. This undergraduate project analyses the production, fermentation and analytical approach of producing high quality wine. Beginning from the picking of grapes, to testing the acidity through a series of titrations, winemaking is truly where science and art collide.

Manipulation Of The Microbiome In The Gut Of The Fruit Fly To Alleviate Cadmium Bioaccumulation, Natasya Tamba

Symposium of Student Scholars

Cadmium (Cd) poisoning contributes to severe bodily detriments characterized by kidney failure, osteomalacia, and osteoporosis, otherwise known as Itai-Itai disease. The ingestion of cadmium contaminated foods primarily causes these conditions. There are no treatments to remove cadmium once absorbed, resulting in bioaccumulation. In this study, we are developing a method to manipulate the community of microorganisms (microbiome) living within the gastrointestinal (GI) tract of the fruit fly (Drosophila melanogaster), intending to use microorganisms to reduce the availability of ingested cadmium.

The biodiversity of microorganisms within the GI tract is responsible for metabolizing substances that the body cannot perform. …

Detecting Bacterial Species From Ancient Human Skeletal Samples, Ariel Owens, Daisy Mcgrath, Tsai-Tien Tseng

Symposium of Student Scholars

This paleopathological study aims to identify Mycobacterium tuberculosis complex (MTBC), Mycobacterium avium complex (MAC) and other Mycobacterium species in silico from skeletal samples that belonged to 28 Polish individuals in the Neolithic period under PRJNA422903 from the Sequence Read Archive (SRA). After next-generation sequencing (NGS), bioinformatics methods are heavily relied upon for identification of pathogens from complex samples. We implemented a bioinformatics pipeline, with custom-built databases, utilizing the following software tools: Trim Galore! and Kraken2. After adapter trimming, Kraken2 was used for taxonomic classifications. We have found that Mycobacterium is present in all 28 individuals. The average percentage of MAC …

Fungi Associated With Herbaceous Plants In Coastal Northern California, Greg Huffman

Natural Sciences and Mathematics | Biological Sciences Master's Theses

The presence of fungal species associated with herbaceous plants was monitored in coastal Marin County, California, USA. The research involved a combination of field sampling surveys and data collection using a stratified random design, pathogen identification through microbiological and molecular analysis, and descriptive analysis and ordination of results. A total of two years of repeated sampling (four times a year) was organized to allow for the detection of seasonal differences in pathogen presence on aerial plant parts. The objective of this study was to identify microbial species present on herbaceous plants using ITS1 sequence analysis. Throughout March of 2018 to …

Open Source Vacuum Oven Design For Low-Temperature Drying: Performance Evaluation For Recycled Pet And Biomass, Benjamin R. Hubbard, Lindsay I. Putman, Stephen Techtmann, Joshua M. Pearce

Michigan Tech Publications, Part 1

Vacuum drying can dehydrate materials further than dry heat methods, while protecting sensitive materials from thermal degradation. Many industries have shifted to vacuum drying as cost-or time-saving measures. Small-scale vacuum drying, however, has been limited by the high costs of specialty scientific tools. To make vacuum drying more accessible, this study provides design and performance information for a small-scale open source vacuum oven, which can be fabricated from off-the-shelf and 3-D printed components. The oven is tested for drying speed and effectiveness on both waste plastic polyethylene terephthalate (PET) and a consortium of bacteria developed for bioprocessing of terephthalate wastes …

The Nutritional Status And Dietary Intake Of Free-Living Seniors: A Cross-Sectional Study, Maeve Lorraine O'Connell, Tara Coppinger, Seán Lacey, Tijana Arsenic, Aoife Louise Mccarthy

Department of Biological Sciences Publications

Background and aims: Older adults are a population group at risk of inadequate nutrition due to reduced appetite, malabsorption, taste alterations and social factors. Yet, dietary investigations in Irish older adults are scarce. The aim of this study was to analyse the nutritional status and dietary intake of a sample of community-dwelling Irish elderly, in addition to the effect of age and gender on dietary intake in this age group.

Methods: Across-sectional study was performed in 162 (n ¼ 91 female, n ¼ 71 male, age 73.8 ± 6.8 years) adults aged 65 years and over in a region of …

Evaluating Kin And Group Selection As Tools For Quantitative Analysis Of Microbial Data, Jeff Smith, Fredrik Inglis

Biology Department Faculty Works

Kin selection and multilevel selection theory are often used to interpret experiments about the evolution of cooperation and social behaviour among microbes. But while these experiments provide rich, detailed fitness data, theory is mostly used as a conceptual heuristic. Here, we evaluate how kin and multilevel selection theory perform as quantitative analysis tools. We reanalyse published microbial datasets and show that the canonical fitness models of both theories are almost always poor fits because they use statistical regressions misspecified for the strong selection and non-additive effects we show are widespread in microbial systems. We identify analytical practices in empirical research …

Synthesis Of Thresholds Of Ocean Acidification Impacts On Echinoderms, N. Bednaršek, P. Calosi, R. A. Feely, R. Ambrose, M. Byrne, Kit Yu Karen Chan, S. Dupont, J. L. Padilla-Gamiño, J. I. Spicer, F. Kessouri, M. Roethler, M. Sutula, S. B. Weisberg

Biology Faculty Works

Assessing the vulnerability of marine invertebrates to ocean acidification (OA) requires an understanding of critical thresholds at which developmental, physiological, and behavioral traits are affected. To identify relevant thresholds for echinoderms, we undertook a three-step data synthesis, focused on California Current Ecosystem (CCE) species. First, literature characterizing echinoderm responses to OA was compiled, creating a dataset comprised of >12,000 datapoints from 41 studies. Analysis of this data set demonstrated responses related to physiology, behavior, growth and development, and increased mortality in the larval and adult stages to low pH exposure. Second, statistical analyses were conducted on selected pathways to identify …

The Regulation Of Chemokinesis By The Soil Amoeba, Dictyostelium Discoideum, Julia Horan

Honors Scholar Theses

Many types of cells crawl on solid surfaces by amoeboid locomotion. Membrane protrusions, such as pseudopods, are generated by outward directed forces and the cell body retracts to allow the cell to migrate on the surface. The movement can be random, or can be directional in response to diffusible (chemotaxis) or surface associated signals (haptotaxis). It has been known for some time that chemotactic signals also lead to an increase in overall cell speed (chemokinesis), however the mechanism of this speed increase is unknown. This project investigates the cellular signaling pathways involved in the regulation of cell speed by ligands …

Coxiella Burnetii And Related Tick Endosymbionts Evolved From Pathogenic Ancestors, Amanda E. Brenner, Sebastián Muñoz-Leal, Madhur Sachan, Marcelo B. Labruna, Rahul Raghavan

Biology Faculty Publications and Presentations

Both symbiotic and pathogenic bacteria in the family Coxiellaceae cause morbidity and mortality in humans and animals. For instance, Coxiella-like endosymbionts (CLEs) improve the reproductive success of ticks—a major disease vector, while Coxiella burnetii causes human Q fever, and uncharacterized coxiellae infect both animals and humans. To better understand the evolution of pathogenesis and symbiosis in this group of intracellular bacteria, we sequenced the genome of a CLE present in the soft tick Ornithodoros amblus (CLEOA) and compared it to the genomes of other bacteria in the order Legionellales. Our analyses confirmed that CLEOA is more closely related to …

Infectious Disease Transmission By Arline Travel, Daniele Provenzano, Sofy Barocio

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Improvements in aviation technology have led to considerable growth of domestic and international flights worldwide especially during the past four decades. Commercial flights have increased the movement of and have connected people from virtually all corners of the globe since the end of World War II to exceed 3 billion passengers a year since 2013: a sizable proportion of the global human population. Flight times have decreased considerably from the onset of commercial aviation and the range of airliners has extended substantially. A passenger harboring an infectious agent embarking a flight on one continent can be deplaning on another continent …

A Forward Genetic Screen To Identify Human Genes Of Interest And Their Roles In Ovarian Cancer, Susan A. Ihejirika

Honors College Theses

Drosophila melanogaster, fruit flies, are very important for modeling and studying human diseases. This study identifies human genes of interest and their contributions to epithelial ovarian carcinogenesis and progression as well as the roles orthologs of these genes play in Drosophila melanogaster. This is important because ovarian cancer is the most common cause of death among the gynecological cancers. This identification of genes was carried out using a forward genetic screen employing the widely used GMR-Gal4 driver/UAS-transgene system. The GMR-Gal4 driver is commonly utilized to express transgenes in the developing eye of the fruit fly. Transgenes that are expressed using …

Evolution Of An Epidermal Differentiation Complex (Edc) Gene Family In Birds, Anthony Davis, Matthew J. Greenwold

Biology Faculty Publications and Presentations

The transition of amniotes to a fully terrestrial lifestyle involved the adaptation of major molecular innovations to the epidermis, often in the form of epidermal appendages such as hair, scales and feathers. Feathers are diverse epidermal structures of birds, and their evolution has played a key role in the expansion of avian species to a wide range of lifestyles and habitats. As with other epidermal appendages, feather development is a complex process which involves many different genetic and protein elements. In mammals, many of the genetic elements involved in epidermal development are located at a specific genetic locus known as …

Evolution Of Extreme Habitat Specialists In The Dark: Cavefishes And Anglerfishes, Pamela Hart

LSU Doctoral Dissertations

Extremophilic organisms are fascinating in that they thrive in physiologically demanding environments. Extreme habitats include subsurface caves and the deep sea, which share several qualities like low light and cold temperatures. Extremophiles have adapted bizarre characteristics that allow them to thrive in such harsh environments including eye and pigment loss (cavefishes) and development of a lure in anglerfishes. These traits are integral to the health and fitness of these organisms, yet the evolutionary history of these traits is unclear.

Cave adaptation has evolved repeatedly across the Tree of Life, famously leading to eye degeneration and loss, yet its macroevolutionary implications …

The Impacts Of Disturbance On Submerged Aquatic Macrophytes Populations Of The Jemez Mountains, New Mexico, Virginia Frances Thompson

Biology ETDs

This dissertation investigates the effects of disturbance (a catastrophic forest fire and decadal-level multi-day flood) on populations of submerged aquatic macrophytes (SAMs) in the streams and rivers of the Jemez Mountains of northern New Mexico, USA. Research conducted and reported in this dissertation addresses the following research questions: 1.) What factors influence the presence or absence of SAMs in Jemez Mountain streams? 2.) How does disturbance (catastrophic wildfire and decadal-level flood) change the amount of aboveground SAM biomass? and 3.) How does that disturbance change the nutrient content (%C, %N, %P) and nutrient stoichiometry of SAMs? These disturbance events had …

Dynamic Mechanisms Of Multidrug Resistance In Human Cancers And Gram Negative Pathogens, Lauren Ammerman

Biological Sciences Theses and Dissertations

This dissertation focuses upon dynamic agents of multidrug resistance (MDR). We used a combination of in silico and in vitro techniques to investigate two membrane transporters that confer MDR – P-glycoprotein, which confers MDR in human cancers, and MtrD, which confers MDR in Neisseria gonorrhoeae. Inhibitors targeting both proteins have tremendous potential for use as co-therapeutics in the treatment of multidrug resistant cancers, or of multidrug resistant infections. However, previously identified inhibitors of P-gp have failed clinical trials due to off-target effects and associated toxicities. Furthermore, the molecular mechanism of antibiotic transport by MtrD is poorly understood, and this dearth …

Mechanisms Of Natural Killer Cell Anti-Tumor Function And Homeostasis, Julia Alexandra Wagner

Arts & Sciences Graduate Student Theses and Dissertations

Natural killer (NK) cells are innate lymphoid cells (ILCs) that mediate anti-tumor and anti-viral immune responses. They do so via two primary effector functions: cytokine production and direct cytotoxicity. Unlike adaptive T and B lymphocytes, NK cells do not rearrange their DNA to express a predominant antigen-specific receptor, and instead express a variety of stochastically-expressed, germline DNA-encoded activating and inhibitory receptors whose signals integrate to govern their functional responses. What results is a diverse repertoire of NK cells capable of recognizing a variety of malignantly-transformed or virally-infected cells. Studies from several groups have established the anti-tumor potential of NK cells, …

The Roles Of Capsular Polysaccharides And Diet In The Immune Response To A Bacteroides Thetaiotaomicron Antigen, Samantha Hsieh

Arts & Sciences Graduate Student Theses and Dissertations

The environment is well recognized to modulate immune responses within the intestinal mucosa in a general fashion. However, the connection between the effects of the environment on the immune response directed towards specific intestinal microbes is unclear. Progress in this area has been hampered by the lack of a model system in which the immune responses to a specific antigen in a gut symbiont can be examined. To this end, we developed a novel CD4+ T cell model, termed BθOM, that is specific for a dominant antigen in the gut symbiont Bacteroides thetaiotaomicron (B. theta). In this work, we use …