Biology Commons^™

Genetic Diversity Of Kemp's Ridley (Lepidochelys Kempii) Sea Turtles On South Padre Island, Texas, Hilary R. Frandsen

Theses and Dissertations

In 2010, researchers observed an abrupt decline in nesting numbers of the Kemp’s ridley following 35 years of positive growth. In wake of this halt, and subsequent lowered nesting averages, evaluation of the genetic diversity of remaining individuals is relevant to investigate the plausibility of a genetic bottleneck, and determine the reproductive stability of the Kemp’s ridley.

Here, I evaluate the genetic diversity within a sampling of the Kemp’s ridleys on South Padre Island using two methods: targeting the mitochondrial control region and targeting the complete mitochondrial genome. Opportunistic samples were donated from juvenile ridleys on the East coast, and …

Foxo3 Regulation Of Stem Cell Markers Oct4 And Sox2 In Pten-Null Glioblastomas, Eduardo Martinez

Theses and Dissertations

The PI3K pathway controls many cellular processes such as cell growth, survival, metabolism, apoptosis, and differentiation. Canonically, PI3K activates AKT leading to subsequent nuclear exportation of FOXO transcription factors. Dysregulation of the PI3K pathway is a hallmark in many cancers and often is attributable to a null mutation in PTEN. PTEN is a phosphatase that reverses the reactions catalyzed by PI3K. Loss of PTEN leads to constitutive inactivation of tumor suppressor FOXO proteins. However, there is increasing evidence that FOXO may still reside and promote transcriptional activity in the nucleus despite high PI3K output within certain advance cancers and …

Phylogeography Of An Estuarian Calanoid Copepod; Acartia Tonsa In The Texas Gulf Of Mexico, Nicole J. Figueroa

Theses and Dissertations

The calanoid copepod, Acartia tonsa is one of the most abundant and well-studied estuarian species. However, the idea that this cosmopolitan species has unrestricted dispersal and high gene flow has been challenged. In this study, a more holistic picture of the phylogeography of A. tonsa was developed using the mitochondrial gene cytochrome oxidase one (mtCOI). Multiple new lineages were found in the Texas Gulf of Mexico that are basal to Northeastern Atlantic lineages. Connectivity was also observed between Brazil and the Texas Gulf of Mexico. The revised phylogeny shows a clear pattern of cryptic speciation as the species made a …

Utilizing Accelerometer Telemetry Tags To Compare Red Snapper (Lutjanus Campechanus) Behavior On Artificial And Natural Reefs, Ethan T. Getz

Theses and Dissertations

The Texas Parks and Wildlife Department Artificial Reef Program has deployed over 2,800 hectares of reefing area composed of petroleum platforms, steel vessels, and concrete. Artificial reefs have been shown to support many important reef fishes such as red snapper (Lutjanus campechanus), however, few studies have compared fish behavior on artificial reefs and natural habitats. We examined activity levels, behavioral patterns and habitat preferences of red snapper over natural reefs, oil platforms and submerged ships. Telemetry tags (Sonotronics model MTT) with tri-axial acceleration range, average depth, and average temperature were programmed to optimize data collection and tag life. …

Gastrin Induces Nuclear Export And Proteasomal Degradation Of Menin In Enteric Glial Cells, Sinju Sundaresan, Cameron A. Meininger, Anthony J. Kang, Amanda L. Photenhauer, Michael M. Hayes, Nirakar Sahoo, Jolanda Lindenberg, Jolanta Grembecka, Tomasz Cierpicki, Lin Ding

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

Background & aims: The multiple endocrine neoplasia, type 1 (MEN1) locus encodes the nuclear protein and tumor suppressor menin. MEN1 mutations frequently cause neuroendocrine tumors such as gastrinomas, characterized by their predominant duodenal location and local metastasis at time of diagnosis. Diffuse gastrin cell hyperplasia precedes the appearance of MEN1 gastrinomas, which develop within submucosal Brunner's glands. We investigated how menin regulates expression of the gastrin gene and induces generation of submucosal gastrin-expressing cell hyperplasia.

Methods: Primary enteric glial cultures were generated from the VillinCre:Men1FL/FL:Sst-/- mice or C57BL/6 mice (controls), with or without inhibition of gastric acid by omeprazole. Primary …

Morganella Morganii (Enterobacteriales: Enterobacteriaceae) Is A Lethal Pathogen Of Mexican Fruit Fly (Diptera: Tephritidae) Larvae, Bacilio Salas, Hugh E. Conway, Erin Schuenzel, Kristen Hopperstad, Christopher Vitek, Don C. Vacek

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

Tephritid pests, such as the Mexican fruit fly, Anastrepha ludens (Loew), represent a major threat to fruit production worldwide. In order to control these pests, sterile insect technique is used to suppress and eradicate wild populations. For this control method to be successful, hundreds of millions of flies must be produced weekly in mass rearing facilities. The large quantity of artificial diet and close proximity of flies at various life stages allows bacteria from family Enterobacteriaceae, Bacillaceae, Pseudomonadaceae, and others to multiply and spread more easily. In this study, bacteria with a possible pathogenic effect were isolated from Mexican fruit …

Co-Independent Modification Of K+ Channels By Tricarbonyldichlororuthenium(Ii) Dimer (Corm-2), Guido Gessner, Nirakar Sahoo, Sandip M. Swain, Gianna Hirth, Roland Schönherr, Ralf Mede, Matthias Westerhausen, Hans Henning Brewitz, Pascal Heimer, Diana Imhof

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

Although toxic when inhaled in high concentrations, the gas carbon monoxide (CO) is endogenously produced in mammals, and various beneficial effects are reported. For potential medicinal applications and studying the molecular processes underlying the pharmacological action of CO, so-called CO-releasing molecules (CORMs), such as tricabonyldichlororuthenium(II) dimer (CORM-2), have been developed and widely used. Yet, it is not readily discriminated whether an observed effect of a CORM is caused by the released CO gas, the CORM itself, or any of its intermediate or final breakdown products. Focusing on Ca2+- and voltage-dependent K+ channels (KCa1.1) and voltage-gated K+ channels (Kv1.5, Kv11.1) relevant …

A Metadata Reporting Framework (Frames) For Synthesis Of Ecohydrological Observations, Danielle S. Christianson, Charuleka Varadharajan, Bradley O. Christoffersen, Matteo Detto, Boris Faybishenko, Bruno O. Gimenez, Val Hendrix, Kolby J. Jardine, Robinson Negron-Juarez, Gilberto Z. Pastorello

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

Metadata describe the ancillary information needed for data preservation and independent interpretation, comparison across heterogeneous datasets, and quality assessment and quality control (QA/QC). Environmental observations are vastly diverse in type and structure, can be taken across a wide range of spatiotemporal scales in a variety of measurement settings and approaches, and saved in multiple formats. Thus, well-organized, consistent metadata are required to produce usable data products from diverse environmental observations collected across field sites. However, existing metadata reporting protocols do not support the complex data synthesis and model-data integration needs of interdisciplinary earth system research. We developed a metadata reporting …

Filtering Out Parasites: Sand Crabs (Lepidopa Benedicti) Are Infected By More Parasites Than Sympatric Mole Crabs (Emerita Benedicti), Zen Faulkes

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

Two digging decapod crustaceans, the sand crab species Lepidopa benedicti and the mole crab species Emerita benedicti, both live in the swash zone of fine sand beaches. They were examined for two parasites that infect decapod crustaceans in the region, an unidentified nematode previously shown to infect L. benedicti, and cestode tapeworm larvae, Polypocephalus sp., previously shown to infect shrimp (Litopenaeus setiferus). Lepidopa benedicti were almost always infected with both parasite species, while E. benedicti were rarely infected with either parasite species. This difference in infection pattern suggests that tapeworms are ingested during sediment feeding in …

T6ss Intraspecific Competition Orchestrates Vibrio Cholerae Genotypic Diversity, Benjamin Kostiuk, Daniel Unterweger, Daniele Provenzano, Stefan Pukatzki

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

Vibrio cholerae is a diverse species that inhabits a wide range of environments from copepods in brackish water to the intestines of humans. In order to remain competitive, V. cholerae uses the versatile type-VI secretion system (T6SS) to secrete anti-prokaryotic and anti-eukaryotic effectors. In addition to competing with other bacterial species, V. cholerae strains also compete with one another. Some strains are able to coexist, and are referred to as belonging to the same compatibility group. Challenged by diverse competitors in various environments, different V. choleare strains secrete different combination of effectors - presumably to best suit their niche. Interestingly, …

Oxidative Insults Disrupt Mitochondrial Dynamics, Iraselia A. Garcia

Theses and Dissertations

Mitochondria form an organellar network to provide ATP to the cell. Mitochondrial DNA (mtDNA) combines with nuclear DNA to encode polypeptides critical to forming the complexes of oxidative phosphorylation in the mitochondrial inner membrane, which generate a transmembrane potential (ΔΨm) to synthesize ATP. This ΔΨm is required to maintain mitochondria fission/fusion dynamics: organellar fusion (mediated by OPA1) and fission events (mediated by DRP1) coordinately regulate mitochondrial dynamics. While oxidative stress correlates with mitochondrial dysfunction, it is unclear how oxidants affect mitochondrial structure/function homeostasis. This project seeks to establish and examine the impact of reactive oxygen species (ROS) on mitochondrial dynamics. …

Effectiveness Of The Flipped Classroom Model In Anatomy And Physiology Laboratory Courses At A Hispanic Serving Institution, Gerardo Sanchez

Theses and Dissertations

A flipped laboratory model involves significant preparation by the students on lab material prior to entry to the laboratory. This allows laboratory time to be focused on active learning through experiments. The aim of this study was to observe changes in student performance through the transition from a traditional laboratory format, to a flipped format. The data showed that for both Anatomy and Physiology (I and II) laboratories a more normal distribution of grades was observed once labs were flipped and lecture grade averages increased. Chi square and analysis of variance tests showed grade changes to a statistically significant degree, …

Central Precocious Puberty Alters The Mammary Gland Epithelial Landscape In Female Rats, Alina M. Hamilton

Theses and Dissertations

Precocious puberty (PP) is a serious endocrine disorder associated with an increased risk for development of breast cancer (BC) later in life. However, the lack of a strong in vivo model has made it difficult to study this relationship. Our group has established manganese (Mn) as a non-toxic activator of the pubertal process. Recently we demonstrated that Mn-induced precocious puberty (MnPP) accelerates E2-regulated mammary gland (MG) development in prepubertal female rats, resulting in persistent proliferation and adult hyperplasia. Using this model, I demonstrate that precocious puberty alters steroidal regulation of proliferation in both the prepubertal and adult virgin MG, altering …

Linking Plant Hydraulics And Beta Diversity In Tropical Forests, Bradley O. Christoffersen, Patrick Meir, Nate G. Mcdowell

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

This article is a Commentary on Cosme et al., 215: 113–125.

Mechanosensing Of Shear By Pseudomonas Aeruginosa Leads To Increased Levels Of The Cyclic-Di-Gmp Signal Initiating Biofilm Development, Christopher A. Rodesney, Brian Roman, Numa Dhamani, Benjamin J. Cooley, Ahmed Touhami, Vernita D. Gordon

Physics & Astronomy Faculty Publications

Biofilms are communities of sessile microbes that are phenotypically distinct from their genetically identical, free-swimming counterparts. Biofilms initiate when bacteria attach to a solid surface. Attachment triggers intracellular signaling to change gene expression from the planktonic to the biofilm phenotype. For Pseudomonas aeruginosa, it has long been known that intracellular levels of the signal cyclic-di-GMP increase upon surface adhesion and that this is required to begin biofilm development. However, what cue is sensed to notify bacteria that they are attached to the surface has not been known. Here, we show that mechanical shear acts as a cue for surface adhesion …

Resaca Supports Range Expansion Of Invasive Apple Snails (Pomacea Maculata Perry, 1810; Caenogastropoda: Ampullariidae) To The Rio Grande Valley, Texas, Kathryn E. Perez, Victoria Garcia Gamboa, Caitlin M. Schneider, Romi L. Burks

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

Resacas, or oxbow lakes, form from old river channels. In the Rio Grande, resacas provide habitat for diverse wildlife, including native and non-native species. Biologists unexpectedly found pink egg masses on emergent vegetation (November 2015) and later adult apple snails (May 2016) within a resaca at a former fish hatchery in Brownsville, Texas. This report extends the non-native range of Pomacea maculata Perry, 1810 by 429 km southeast in Texas. Our findings imply that abandoned waterbodies, such as fish hatcheries, can act as unrecognized conduits for non-native invasive species.

Assessment Of Long-Term Effects Of Woody Plants Expansion In Humid, Tropical Grassland Of Venezuela, Soraya A. Delgado

Theses and Dissertations

The invasion of woody plants into grassland communities, or shrub encroachment, is a worldwide phenomenon usually attributed to anthropogenic interference. Most studies have focused on temperate and arctic biomes. Less is known about how shrub encroachment is affecting humid tropical grasslands, which have different climates, higher levels of biodiversity and different histories of human land use. This project quantifies the rate of woody vegetation change in a humid tropical grassland of Venezuela using remote sensing over the past quarter century and ground based measurements of selected individual species. Results of remote sensing indicate high rates of conversion of grasslands to …

Applications Of Side Scan And Parametric Echosounders For Mapping Shallow Seagrass Habitats And Their Associated Organic Carbon, Austin L. Greene

Theses and Dissertations

Despite a global valuation of $1.9 trillion seagrass habitats world-wide are in decline—directly impacting the large soil carbon stocks associated with seagrasses. Many methods exist to measure the health of seagrass habitats, yet few apply to shallow coastal ecosystems. Those that do lack spatial resolution (satellite surveys) or do not provide continuous data across large areas (point-based surveys). Furthermore, carbon content of these ecosystems is largely limited to destructive and time-consuming soil core sampling. Side scan and parametric acoustics represent a unique technological opportunity to study habitat coverage and carbon content of vegetated coastal habitats (< 3 m depth). This study presents proof of concept for applications of recreational side scan and parametric sub-bottom profiling sonars in mapping both habitat coverage and organic carbon distribution in shallow seagrass habitats, and explores how these methods might be improved in future applications.

Decomposition Of Black Mangrove (Avicennia Germinans ) Leaf Litter: Calibrating Estuarine Indicators Of Functional Recovery, Leticia Martinez Contreras

Theses and Dissertations

Decomposition of plant material produced by mangroves and other macrophytes in estuaries occurs in both sediments and the water column. Early and intense processing could be more common in the water. In a previous study, in situ decomposition rates of Black Mangrove (Avicennia germinans ) leaf litter suspended in the water column differed among three estuaries in south Texas with moderate differences in salinity, water temperature, available nitrogen (N), and tidal flow. A series of microcosm experiments were conducted to determine the influence, within observed ranges in the estuaries, of these water variables on mass loss of Black Mangrove …

Genetic Variation In Two Economically Important Arthropod Vectors Of Citrus Diseases, Alejandra Fuentes

Theses and Dissertations

Arthropod vectors are agriculturally and ecologically important because they transmit numerous plant pathogens. Commonly, control strategies for vector-borne plant pathogens focus on suppression of vector populations. Genetic variation studies in pest populations provide useful information for biological control, understanding pesticide resistance, and inferring global movement patterns. In chapter I, genetic variation of worldwide populations of Diaphorina citri, the vector of Citrus greening disease, was examined to assess potential sites of origin of invasive populations. The results showed population structure at regional levels, suggesting limited gene flow and revealing patterns of invasion. In chapter II, I explored the community of …

Increasing Marine Debris Awareness Through Public Education And Analyzing Fish For Microplastic And Pollutant Contamination, Stephanie R. Dubois

Theses and Dissertations

Marine debris is any persistent solid material that is manmade and then disposed of into the world’s oceans. Outreach and education was used in combination with biological research using an indicator fish species to raise awareness about the impacts of marine debris and encourage change in behavior to reduce marine debris. Pre and post surveys were administered during marine debris education tours for K-12 students at the Coastal Studies Lab on South Padre Island, Texas to determine change in knowledge and behavior regarding marine debris. Pinfish were collected from Laguna Madre and stomachs and livers removed for microplastics content and …

The Vocal Babbling Behavior And Its Sibling Effects In A Wild Parrot, Tatiana Dolgushina

Theses and Dissertations

Vocal learning is a rare trait in the animal kingdom, defined as the sensorimotor imitation of sounds, and is only found in select groups of birds and mammals. Parrots are a behaviorally complex group of birds, famous for their ability to mimic social companions, but how they develop this ability in the wild has received little attention. The vocal learning period consists of a complex vocal babbling stage, a crucial developmental precursor for imitation of adult vocalizations in humans and songbirds, but has not been described in any of the 360+ parrot species. This project quantifies potential individual variation in …

Multifunctionality Of Cover Crops On Organic Vegetable Farms In South Texas, Savannah M. Rugg

Theses and Dissertations

Situated in deep South Texas, the Lower Rio Grande Valley (LRGV) is considered one the most productive agricultural regions in the southern US. With the highest concentration of organic farms in the state (Hidalgo county), finding management practices that comply with organic certification is increasingly pertinent. Cover cropping can serve multiple functions in an agroecosystem such as: suppressing weeds, increasing soil organic matter (SOM), increasing soil nitrates, and enhancing soil biodiversity. The four cover crops (lablab, sunn hemp, sudangrass, and pearl millet) were assessed to see their potential to increase soil nitrogen, to increase soil organic matter, and to suppress …

Understanding The Patterns Of Distribution And Abundance Of Lyme Disease Carrying Ticks And Their Hosts, Julio Ruiz

Honors Theses

Lyme disease is caused by the bacteria Borrelia burgodorferi and spreads to their hosts by the bites of infected Ixodes scapularis ticks. In the United States, Lyme disease is typically found in the northeast but in recent years the disease has begun to be found further south and west than previously before. Yet, today, little information can be found about the patters of distribution and abundance of ticks and their host. The main goal of this research work was to expand the knowledge of the abundance and distribution of ticks and host. Based on tick collection data obtained from Maikis …

A Threshold Of Transmembrane Potential Is Required For Mitochondrial Dynamic Balance Mediated By Drp1 And Oma1, Edith Jones, Norma Gaytan, Iraselia Garcia, Alan Herrera, Manuel Ramos, Divya Agarwala, Maahrose Rana, Wendy Innis-Whitehouse, Erin Schuenzel, Robert Gilkerson

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

As an organellar network, mitochondria dynamically regulate their organization via opposing fusion and fission pathways to maintain bioenergetic homeostasis and contribute to key cellular pathways. This dynamic balance is directly linked to bioenergetic function: loss of transmembrane potential across the inner membrane (Dwm) disrupts mitochondrial fission/fusion balance, causing fragmentation of the network. However, the level of Dwm required for mitochondrial dynamic balance, as well as the relative contributions of fission and fusion pathways, have remained unclear. To explore this, mitochondrial morphology and Dwm were examined via confocal imaging and tetramethyl rhodamine ester (TMRE) flow cytometry, respectively, in cultured 143B osteosarcoma …

The Phenology Of Sand Crabs, Lepidopa Benedicti (Decapoda: Albuneidae), Zen Faulkes

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

Albuneid sand crabs are widespread on sandy beaches around the world, but because they conceal themselves by digging in sand and are often found at low densities, little is known about their basic biology. Lepidopa species were collected from the beaches of South Padre Island, Texas, on the western coast of Gulf of Mexico, a location that had previously been suggested to act as a population sink. The site contained Lepidopa benedicti and L. websteri, although the latter was extremely rare (collected three times in 5 years). There was significant variation in abundance across the year, with higher densities …

The Role Of Language In Anatomy And Physiology Instruction, Angela M. Chapman, Hsuying C. Ward, Ashwini Tiwari, Amy Weimer, Jaime B. Duran, Federico R. Guerra, Robert Paul Sale

Teaching and Learning Faculty Publications

Research indicates that student learning of science, student attitudes toward science, and their motivation to learn science and pursue science-related careers is related to classroom instruction. This study examined anatomy and physiology (A&P) classes in a south Texas high school where 97 percent of students are Hispanic bilingual learners. Classes were assigned to control or treatment groups, with the treatment group receiving instruction designed to help students develop a deeper understanding of anatomy vocabulary related to brain structures by making connections to these words in everyday life as well as to their understanding of Spanish. Main effects between group and …

Sequential Displacement Of Type Vi Secretion System Effector Genes Leads To Evolution Of Diverse Immunity Gene Arrays In Vibrio Cholerae, Paul C. Kirchberger, Daniel Unterweger, Daniele Provenzano, Stefan Pukatzki, Yan Boucher

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

Type VI secretion systems (T6SS) enable bacteria to engage neighboring cells in contact-dependent competition. In Vibrio cholerae, three chromosomal clusters each encode a pair of effector and immunity genes downstream of those encoding the T6SS structural machinery for effector delivery. Different combinations of effector-immunity proteins lead to competition between strains of V. cholerae, which are thought to be protected only from the toxicity of their own effectors. Screening of all publically available V. cholerae genomes showed that numerous strains possess long arrays of orphan immunity genes encoded in the 3' region of their T6SS clusters. Phylogenetic analysis reveals that these …

Survivorship And Growth Among Three Developmental Stages Of Black Mangrove (Avicennia Germinans) Seedlings In Southernmost Texas, Frank W. Judd, Kenneth R. Sunny, Robert I. Lonard, Ruben A. Mazariegos

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

Black mangrove is useful for shoreline stabilization in Texas and Mexico but there is insufficient information regarding propagule survivorship and seedling growth. We compared survivorship and growth of three develop-mental groups of black mangrove seedlings planted on three dredge spoil islands in the Lower Laguna Madre of Texas, to better understand optimum planting strategy. Each spoil island had 100 seedlings without emergent radicles, 100 seedlings with emergent radicles, and 75 head-started seedlings. Survivorship of seedlings with and with-out emergent radicles was low, (0-16%). Survivorship of head-started seedlings was higher, (60 – 62.7%). Varia-tion in survivorship among developmental categories was significant …

Protective Effect Of Anti-Phosphatidylserine Antibody In A Guinea Pig Model Of Advanced Hemorrhagic Arenavirus Infection, John M. Thomas, Philip E. Thorpe

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

Objective: Host derived markers on virally infected cells or virions may provide targets for the generation of antiviral agents. Recently, we identified phosphatidylserine (PS) as a host marker of virions and virally-infected cells.

Methods and Materials: Under normal physiological conditions, PS is maintained on the inner leaflet of the plasma membrane facing the cytosol. Following viral infection, activation or pre-apoptotic changes cause PS to become externalized. We have previously shown that bavituximab, a chimeric human-mouse antibody that binds PS complexed with β2-glycoprotein I (β2GP1), protected rodents against lethal Pichinde virus and cytomegalovirus infections.

Results: Here, we determined the antiviral activity …