Life Sciences Commons^™

Impact Of Hydrologic Alteration On Brazos River Pelagophilic Minnows, Christopher M. Taylor, Kevin B. Mayes

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

The lower Brazos River has been profoundly altered since the construction of multiple impoundments. The resulting river regulation poses problems for organisms adapted to a natural flow regime and is thought to play a major role in the imperilment of seven native minnows that synchronize spawning during high flow pulses. Four of the species are presumably extirpated from the region, but their declines and losses differed across time. To address potential reasons for species’ declines, we assessed pre- and post-impoundment changes in flow regime from five gaging stations across the lower Brazos River to identify river flow characteristics that depart …

Nectar Source Preferences Of The Hummingbird: A Field Study From South Texas, Jasmine Benavidez

Honors Theses

With the rise of urbanization, comes a rise in urban-like activities—most notable is birdfeeding. Given the increasing popularity of bird-feeding, especially in hummingbird feeding, concern for implications, if any, has mounted. There is reason to believe that artificial feeders can impact the surrounding environment; that is, it is possible that feeders could attract pollinators away from flowering plants, which, in turn, could bring repercussions for pollination and all associated with it. However, literature, on the matter, is rather limited. To add to this, past studies provide two opposing arguments. This study aims to explore the nectar source preferences of hummingbirds …

Development And Assessment Of An Environmental Dna (Edna) Assay For A Cryptic Siren (Amphibia: Sirenidae), Krista M. Ruppert, Drew R. Davis, Md Saydur Rahman, Richard J. Kline

School of Earth, Environmental, & Marine Sciences Faculty Publications

Environmental DNA (eDNA) assays have become a major aspect of surveys for aquatic organisms in the past decade. These methods are highly sensitive, making them well-suited for monitoring rare and cryptic species. Current efforts to study the Rio Grande Siren in southern Texas have been hampered due to the cryptic nature of these aquatic salamanders. Arid conditions further add to the difficulty in studying this species, as many water bodies they inhabit are ephemeral, sometimes constraining sampling efforts to a short window after heavy rain. Additionally, sirens are known to cease activity and reside underground when ponds begin to dry …

Characterization Of Particulate Matter Species In An Area Impacted By Aggregate And Limestone Mining North Of San Antonio, Tx, Usa, Amit U. Raysoni, Esmeralda Mendez, August Luna, Joe Collins

School of Earth, Environmental, & Marine Sciences Faculty Publications

Aggregate and limestone mining in San Antonio's Bexar and Comal counties in Texas, USA, has caused considerable health concerns as of late. Aggregate mining actions can result in localized air quality issues in any neighborhood. Furthermore, heavy truck traffic, hauling, and transportation of the mined material contribute to pollution. In this research, PM species were sampled at four locations north of the San Antonio city limits. The data were collected using a TSI Air Quality Sampler that sampled PM1, PM2.5, PM4, PM10, wind speed, wind direction, temperature, and relative humidity. Continuous data with 1 min averages were recorded during the …

Cover Crops May Exacerbate Moisture Limitations On South Texas Dryland Farms, Stephanie Kasper, Faeqa Mohsin, Lindsey Richards, Alexis Racelis

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

Cover crops are a sustainable management tool for mediating weed pressure, reducing soil erosion, and enhancing soil organic carbon (C) and nitrogen (N) levels. Yet, adoption rates across water-limited farms in Texas remain low, especially among producers without irrigation access, due to concerns that cover crop use of soil moisture will negatively impact subsequent cash crop yields. This three-year cover crop trial in a rain-fed sorghum (Sorghum bicolor L.) farm in Lyford, Texas, trialed different cover crop mixes and seeding rates and confirmed that cover cropping leads to significant soil moisture deficits and cash crop failure when rainfall is low …

Screening Commercial Entomopathogenic Fungi For The Management Of Diaphorina Citri Populations In The Lower Rio Grande Valley, Texas, Usa, Justin Wendel, Jonathan Cisneros, Stefan Jaronski, Christopher Vitek, Matthew Ciomperlik, Daniel Flores

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

Ten strains of entomopathogenic ascomycete fungi, sourced from commercial formulations of blastopore or conidiospore formulations, were tested in 14 different formulations in a primary acquisition/direct spray bioassay against adult Asian citrus psyllid (Diaphorina citri Kuwayama (Hemiptera: Liviidae)). The Cordyceps (Isaria) javanica Apopka 97-C (conidia) strain was used as the standard. A statistical ranking system was established in which top performing pathogenic strains were selected for further screening and eventual field trials. Modified Potter-type spray towers were utilized to deliver a range of doses of viable spores to adult D. citri in an aqueous spray consistent with …

Diel Activity Patterns Of Two Distinct Populations Of Aedes Aegypti In Miami, Fl And Brownsville, Tx, John-Paul Mutebi, André Barretto Bruno Wilke, Erik Ostrum, Chalmers Vasquez, Gabriel Cardenas, Augusto Carvajal, Maday Moreno, William D. Petrie, Arturo Rodriguez, Henry Presas, Jesus Rodriguez, Fred Barnes, Christopher Vitek, Xochitl Estrada, Thalia Rios, Jeremy Marshall

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

The diel biting activity of Aedes (Stegomyia) aegypti (L) populations was extensively investigated in the early 1900s to gain more information on the biology of Ae. aegypti, and this information was used to devise effective approaches to controlling populations of this species and protect the human population from widespread arbovirus outbreaks. However, few contemporary studies are available regarding the diel activity patterns of Ae. aegypti. To assess the diel activity patterns of Ae. aegypti in southern Florida and Texas, we conducted 96-h uninterrupted mosquito collections once each month from May through November 2019 in Miami, Florida, and Brownsville, Texas, using …

Acute And Chronic Bone Marker And Endocrine Responses To Resistance Exercise With And Without Blood Flow Restriction In Young Men, Debra A. Bemben, Vanessa D. Sherk, Samuel R. Buchanan, Sojung Kim, Kyle Sherk, Michael G. Bemben

Health & Human Performance Faculty Publications

In this study, we compared acute and chronic bone marker and hormone responses to 6 weeks of low intensity (20% 1RM) blood flow restriction (BFR20) resistance training to high intensity (70% 1RM) traditional resistance training (TR70) and moderate intensity (45% 1RM) traditional resistance training (TR45) in young men (18–35 years). Participants were randomized to one of the training groups or to a control group (CON). The following training programs were performed 3 days per week for 6 weeks for knee extension and knee flexion exercises: BFR20, 20%1RM, 4 sets (30, 15, 15, 15 reps) wearing blood flow restriction cuffs around …

Comparative Evaluation Of Physicochemical And Fermentative Responses Of Three Sorghum Varieties From Dryland And Irrigated Land And The Properties Of Proteins From Distillers’ Grains, Jikai Zhao, Thomas Weiss, Zhenjiao Du, Shan Hong, Scott R. Bean, Yonghui Li, Donghai Wang

School of Earth, Environmental, & Marine Sciences Faculty Publications

Three sorghum varieties [waxy sorghum (WS), high protein sorghum (HPS), and normal sorghum (NS)] grown under dryland and irrigated conditions were evaluated with respect to the physicochemical and fermentative properties. The proteins were extracted from wet distillers' grains with solubles (WDGS) and characterized in terms of purity and in vitro digestibility. Starch, crude protein, crude fat, and fiber contents of the sorghums ranged from 64.16 to 68.05 g/100 g, 11.49–13.54 g/100 g, 2.45–2.98 g/100 g, and 1.62–1.80 g/100 g, respectively. For the same variety, the sorghums grown under dryland conditions had higher protein (0.33–0.91 g/100 g) and lower …

Now You See Me: “First” Records Of The Greater Amberjack Seriola Dumerili At Rapa Nui Range Extension Or Increased Scientific Effort?, Naiti Morales, Amy Rose Coghlan, Erin E. Easton, Alan M. Friedlander, James J. Herlan, Carlos F. Gaymer

School of Earth, Environmental, & Marine Sciences Faculty Publications

We report new records of the fisheries-harvested subtropical greater amberjack Seriola dumerili for the south-east Pacific Ocean. Previously, only one species of Seriola (the yellowtail amberjack Seriola lalandi) was scientifically recorded for Rapa Nui (also known as Easter Island) despite local fishers' asserting that three Seriola morphotypes are found in the region. Here we present the first 'scientific record' of what could be a pre-existing (albeit transient) species of the Rapa Nui ecoregion. Establishing the existing range limits of commercially and ecologically valuable species is key for observing climate-driven distribution shifts, and the inclusion of traditional ecological knowledge is likely …

A Tail Of Plumage Colouration: Disentangling Geographic, Seasonal And Dietary Effects On Plumage Colour In A Migratory Songbird, Sean M. Mahoney, Matthew W. Reudink, Andrea Contina, Kelly A. Roberts, Veronica T. Schabert, Emily G. Gunther, Kristen M. Covino

School of Integrative Biological & Chemical Sciences Faculty Publications

Plumage ornamentation in birds serves critical inter- and intra-sexual signaling functions. While carotenoid-based plumage colouration is often viewed as a classic condition-dependent sexually selected trait, plumage colouration can be influenced by a wide array of both intrinsic and extrinsic factors. Understanding the mechanisms underlying variation in colouration is especially important for species where the signaling function of ornamental traits is complex or when the literature is conflicting. Here, we examined variation in the yellow/orange tail feathers of American redstarts Setophaga ruticilla passing through two migratory stopover sites in eastern North America during both spring and fall migration to assess the …

Insecticide Resistance In Aedes Aegypti Varies Seasonally And Geographically In Texas/Mexico Border Cities, Heather Hernandez, Flor A. Martinez, Christopher Vitek

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

Insecticide use is the primary method of attempting to reduce or control the spread of mosquito-borne diseases. Insecticide resistance is a major concern as resistance will limit the efficacy of vector-control efforts. The lower Rio Grande Valley region of South Texas has had autochthonous transmission of multiple mosquito-borne diseases including those caused by dengue virus, chikungunya virus, and Zika virus. However, the current status of mosquito resistance to commonly used pesticides in this region is unknown. In this study, we collected field samples from multiple municipalities in South Texas and assessed resistance using the Centers for Disease Control and Prevention …

Reducing Adverse Impacts Of Amazon Hydropower Expansion, Alexander S. Flecker, Qinru Shi, Rafael M. Almeida, Héctor Angarita, Jonathan M. Gomes-Selman, Roosevelt García-Villacorta, Suresh A. Sethi, Steven A. Thomas, N Leroy Poff, Bruce R. Forsberg

School of Earth, Environmental, & Marine Sciences Faculty Publications

Proposed hydropower dams at more than 350 sites throughout the Amazon require strategic evaluation of trade-offs between the numerous ecosystem services provided by Earth's largest and most biodiverse river basin. These services are spatially variable, hence collective impacts of newly built dams depend strongly on their configuration. We use multiobjective optimization to identify portfolios of sites that simultaneously minimize impacts on river flow, river connectivity, sediment transport, fish diversity, and greenhouse gas emissions while achieving energy production goals. We find that uncoordinated, dam-by-dam hydropower expansion has resulted in forgone ecosystem service benefits. Minimizing further damage from hydropower development requires considering …

Filling The Gap: Molting Behavior Of Colima Warblers And Research Opportunities For Understudied North American Songbirds, Benjamin Gochanour, Jose L. Alcantara, Paula Cimprich, Jeffrey F. Kelly, Andrea Contina

School of Integrative Biological & Chemical Sciences Faculty Publications

We implemented stable isotope analysis to evaluate the molt behavior of the Colima warbler (Leiothlypis crissalis), an understudied migratory songbird occurring in Mexico and recently discovered breeding in the southern part of Texas, USA. We built a geostatistical model showing variation in deuterium precipitation values (d2Hp) across a latitudinal gradient within the Colima warbler breeding range in northeastern Mexico. Then, based on stable isotope ratios of deuterium in feathers (d2Hf), we assigned wintering Colima warblers captured in Central Mexico to possible molting areas near the southwestern portion of the species' breeding range. To the best of our knowledge, this is …

Assessment Of Two Novel Host-Derived Beauveria Bassiana (Hypocreales: Cordycipitaceae) Isolates Against The Citrus Pest, Diaphorina Citri (Hemiptera: Liviidae), Jonathan Cisneros, Justin Wendel, Stefan Jaronski, Christopher Vitek, Matthew Ciomperlik, Daniel Flores

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

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vectors ‘Candidatus Liberibacter spp.’, the causative agent of Citrus Greening Disease (CGD) or Huanglongbing (HLB). Managing populations of psyllids in the Lower Rio Grande Valley (LRGV), TX, United States is imperative given a continuous increase in HLB-positive trees. A component of integrated pest management (IPM) program is the use of strains of entomopathogenic fungi for the biological control of D. citri. In an attempt to find endemic strains of entomopathogenic fungi that grow favorably under LRGV environmental conditions and naturally infect D. citri, psyllids were collected from …

Review Of The Invasive Forage Grass, Guinea Grass (Megathyrsus Maximus): Ecology And Potential Impacts In Arid And Semi-Arid Regions, Pushpa Soti, Vanessa Thomas

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

Several introduced African grasses are known to present recurring patterns of invasiveness and cause a severe impact on the diversity and functioning of ecosystems worldwide. Megathyrsus maximus (Guinea grass), a forage grass species native to South Africa, is reported to be highly invasive and pose a serious threat to native biodiversity in the introduced range. Despite the severe ecological threats posed by M. maximus worldwide, there is a dearth of information on the ecological and agroecological impact of M. maximus when growing in unintended areas. In this review, we present general information on M. maximus, its distribution and ecological …

Dissecting The Shared Genetic Architecture Of Suicide Attempt, Psychiatric Disorders, And Known Risk Factors, Niamh Mullins, Joo Eun Kang, Adrian I. Campos, Jonathan R.I. Coleman, Ney Alliey Rodriguez

School of Medicine Publications

Background: Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods: We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. …

Identifying Available Resources And Agricultural Practices Useful In Soil Fertility Management To Support Orange-Fleshed Sweet Potato Cultivation On Smallholder Farms In Mozambique, Rafaela Feola Conz, Engil Isadora Pujol Pereira, Abdul Naico, Maria Isabel Andrade, Johan Six

School of Earth, Environmental, & Marine Sciences Faculty Publications

Orange-fleshed sweet potato is an important source of macro-and micronutrients for humans, particularly in resource-poor rural communities. However, sweet potato cultivation removes large amounts of nutrients from the soil. Hence, soil fertility replenishment is vital to secure long-term food production. The lack of access to fertilizers hinders the ability of farmers to supply and replenish soil nutrients, intensifying food insecurity. This study aimed at identifying locally available organic residues and agricultural practices with potential application in soil fertility management to prevent soil degradation in southern Mozambique. We conducted a survey to gather information on the farmers’ demographics and farming systems …

Native And Non-Native Plant Species Differentially Affect Arthropod Community Dynamics With Consequences For Crop Production In Lower Rio Grande Valley, Kaitlynn Lavallee, Pushpa G. Soti, Alexis Racelis, Rupesh R. Kariyat

School of Earth, Environmental, & Marine Sciences Faculty Publications

In agricultural ecosystems, arthropods play critical roles- including biocontrol, pollination services, and as herbivores. While herbivory negatively affects crop production, the recent decline in beneficial insect numbers have created a global concern, and consequently have led into multiple lines of conservation strategies. Agroecological practices that can provide sustenance, nesting, and refuge for beneficial organisms are considered as some of them, except we lack a better understanding of how seasonal and crop specific variation can affect their community dynamics. In this study, we examined this by investigating how native and non-native plants, when incorporated into a vegetable agroecosystem in Lower Rio …

Saturating Relationship Between Phytoplankton Growth Rate And Nutrient Concentration Explained By Macromolecular Allocation, Jongsun Kim, Gabrielle Armin, Keisuke Inomura

School of Earth, Environmental, & Marine Sciences Faculty Publications

Phytoplankton account for about a half of photosynthesis in the world, making them a key player in the ecological and biogeochemical systems. One of the key traits of phytoplankton is their growth rate because it indicates their productivity and affects their competitive capability. The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed yet the mechanisms behind the relationship remain elusive. Here we use a mechanistic model and metadata of phytoplankton to show that the saturating relationship between growth rate and nitrate concentration can be interpreted by intracellular macromolecular allocation. At low nitrate levels, the …

Bone, Biomarker, Body Composition, And Performance Responses To 8 Weeks Of Reserve Officers' Training Corps Training, Breanne S. Baker, Samuel R. Buchanan, Christopher D. Black, Michael G. Bemben, Debra A. Bemben

Health & Human Performance Faculty Publications

Context: Military personnel engage in vigorous exercise, often resulting in higher bone mineral density; however, leg bone injuries occur frequently in this population. Predictors of change in tibial bone quality and strength need to be characterized in this high-risk population.

Objectives: To examine the effects of an 8-week military training intervention on total body and site-specific bone density and tibial bone quality, serum biomarkers (parathyroid hormone and sclerostin), body composition, and physical performance and to investigate which outcome variables (biomarkers, body composition, and physical performance) predict estimated tibial bone strength in college-aged Reserve Officers' Training Corps (ROTC) participants.

Design: Prospective …

Sex-Dependent Shared And Nonshared Genetic Architecture Across Mood And Psychotic Disorders, Gabriëlla A. M. Blokland, Jakob Grove, Chia Yen Chen, Chris Cotsapas, Ney Alliey Rodriguez

School of Medicine Publications

Background: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk. Methods: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH. Results: Across disorders, genome-wide significant single nucleotide polymorphism–by-sex interaction was detected for a locus encompassing NKAIN2 (rs117780815, p = 3.2 × 10^{−8 …}

Evaluation Of The Equivalence Of Different Intakes Of Fruitflow In Affecting Platelet Aggregation And Thrombin Generation Capacity In A Randomized, Double-Blinded Pilot Study In Male Subjects, Ranjit Kumar Das, Tanushree Datta, Dipankar Biswas, Ruedi Duss, Niamh O’Kennedy, Asim K. Duttaroy

Health & Biomedical Sciences Faculty Publications

Background: The water-soluble tomato extract, Fruitflow® is a dietary antiplatelet which can be used to lower platelet aggregability in primary preventative settings. We carried out a pilot study to investigate the range of intakes linked to efficacy and to make an initial assessment of variability in response to Fruitflow®.

Methods: Platelet response to adenosine diphosphate (ADP) agonist and thrombin generation capacity were monitored at baseline and 24 h after consuming 0, 30, 75, 150 or 300 mg of Fruitflow® in a randomized, double-blinded crossover study in male subjects 30-65 years of age (N = 12). Results were evaluated for equivalence …

Characterization Of Biomarkers For Alzheimer’S Disease And Hiv-1 Associated Neurocognitive Disorders, Armando Garces Iii

Theses and Dissertations

Alzheimer’s disease is a neurodegenerative disorder that is characterized by progressive cognitive decline and the accumulation of amyloid beta and neurofibrillary tangles in regions of the brain. These protein deposits are known to generate multiple effects on the brain that lead to neurodegeneration. It has been established that (Human Immunodeficiency Virus) HIV-1 accelerates the aging process of people living with HIV-1. Moreover, there is significant clinical evidence indicating a potential link between the neurodegeneration developed by those with an HIV-1 infection and AD. HIV-1 viral infection causes cognitive impairment known as …

Effects Of Scarification, Phytohormones, Stratification, Soil Types And Warming On The Germination And/Or Performance Of Three Tamaulipan Thornscrub Species, Paula Luera

Theses and Dissertations

The Tamaulipan thornforests of south Texas and northeast Mexico are an ecologically and economically important conservation hotspot. Thornforest restoration is limited by native tree and shrub seedling availability for planting. Seedling shortages arise from low seed availability and knowledge gaps regarding best practices for germinating and growing the 70+ thornforest species desired for restoration plantings. To fill key knowledge gaps, we investigated three ecologically important thornforest species with low or highly variable germination or seedling survival rates: Ebenopsis ebano, Cordia boissieri, and Zanthoxylum fagara. For each, we quantified the effects of different dosages of chemical seed treatments …

Exploring The Role Of Stigmatic Exudate In The Water Lily (Nymphaceae) Pollination Mechanism Using N. Ampla (Salisb. Dc.), Luis Uribe

Theses and Dissertations

Water lilies are the only known plant group that uses hyperactive nectar glands to divest pollinators of their pollen. The nectar in Nymphaea ampla is thought to contain secondary metabolites that increase pollen deposition possibly by modifying pollinator behavior. This was explored utilizing visitation and fecundity data from the field coupled with survival and behavioral experiments in the laboratory. Replacing nectar with water reduced seed set in N. ampla which was attributed to reduced visitation in water-bearing flowers and not to effects on pollinator detention time. Exposure to nectar did not reduce survivability in Apis mellifera. Pollen and nectar foragers …

Bullet-Proof Boll Weevil: The History Of Boll Weevil Eradication, Evan A. Berg

Theses and Dissertations

Farmers and entomologists have all experimented with various methods to find the best way to defeat the United States' boll weevil. The techniques themselves, while expansive, can be examined within the scope of the years that they were used. This provides an exciting insight into how cotton pest management became more complex as the decades moved on and revealed how the science of cotton pest management evolved to deal with the boll weevil and other future cotton threats.

Evolutionary Development Study Of Firebrat (Thermobia Domestica), Luis Cantu Jr.

Theses and Dissertations

As most evolutionary development studies regarding wing origin take place using insects taxonomically closer to model organism, Drosophila melanogaster, there is a need of expanding studies to lower clades. While D. melanogaster is higher phylogenetically, basal clades would allow for a historical perspective of what occurs within the gene flow of conservative biomarkers. Further understanding of wings and flight would allow for a clearer understanding of how the migration of insects from sea to land has allowed them to become one of the most speciose taxa. Through the study of Thermobia Domestica, part of the Zygentoma, we expand on comprehension …

Characterization Of Soil Nematode Community As Influenced By Weedy Plants And Edaphic Properties, Orlando Garcia

Theses and Dissertations

Nematodes are one of the most critical species globally as they are part of most nutrient recycling. While nematodes play a vital role in nutrient cycling, little is known about them from an ecological standpoint. The majority of current research has focused on a singular component of the community, being those of herbivore/plant-parasitic nematodes. In this study, the community shifts of the nematode trophic groups were analyzed as influenced by native and invasive grasses species in the Lower Rio Grande Valley (LRGV) with the addition of edaphic soil properties.

In our study, the results indicate changes in the composition of …

A Gis-Based Model To Assess On-Site Sewage Facility (Ossf) Contamination Risk To Local Water Resources, Alvaro Garcia

Theses and Dissertations

In a collaborative effort between Texas Water Resources Institute (TWRI), Cameron County Public Health (CCPH), Texas A&M AgriLife Extension (TAMAE), and the University of Texas Rio Grande Valley (UTRGV), a GIS database that includes relevant OSSF information, such as location, system age, lot size, and other important parameters was created.

This OSSF database, along with publicly available GIS data, was used to create an integrative GIS-based risk assessment model where OSSF risk parameters were assigned a risk factor and combined into a spatial contamination risk for surrounding areas and their receiving waterbodies. Parameters were broken down into two categories: environmental …