Life Sciences Commons^™

The Direct Role Of Enzyme Hydrolysis On Ammonium Regeneration Rates In Estuarine Sediments, Afonso C. Souza, Tamara K. Pease, Wayne S. Gardner

Biology Faculty Publications and Presentations

Benthic ammonium (NH4 +) regeneration in coastal marine sediments has a fundamental role in nitrogen (N) cycling and N supply to primary producers. Nitrogen regeneration involves benthic microbial mineralization of organic-N, which, in turn, depends on protein hydrolysis. These processes were examined in Aransas Bay (Texas, USA) sediments by monitoring NH4 + evolution as a function of enzyme activity in controlled sediment slurries. Casein and tannic acid were added to evaluate the direct role of aminopeptidase on NH4 + production and the effects of a polyphenolic enzyme inhibitor, respectively. Casein additions increased the NH4 + concentration from 19 ± 0.3 …

The Study Of The Parasitic Fauna In Sciaenops Ocellatus, Lower Laguna Madre, Texas, Veronica Abrigo

Theses and Dissertations - UTB/UTPA

Parasitological investigations provide information on ecosystem health because parasite prevalence and abundance are influenced by biotic and abiotic environmental changes. This survey classified the parasitic fauna of red drum, Sciaenops ocellatus, in the Lower Laguna Madre, TX. Fish (n = 239) were collected from four study sites (May 2005 - June 2006). Parasite identification consisted of digenean and monogenean trematodes, cestodes, larval nematodes, copepods, and protozoans. Parasite prevalence and host length was positively correlated from South Bay (r=0.473), Port Isabel (r=0.533), Arroyo(r=0.314), and Port Mansfield (r=0.630). Significant differences (p<0.001) between zone and parasite prevalence from Arroyo site indicated a higher prevalence of protozoa and monogeneans and reduced prevalence of digeneans. Statistical analyses indicated the greatest difference between Port Isabel and Arroyo sites ( divided by 2= 48.195; p<0.001; df= 14), and the least difference between South Bay and Arroyo sites ( divided by 2= 20.847; p= 1.06; df= 14).

Characterization And Antibiotic Resistance Profile Of Staphylococci In The Lower Rio Grande Valley, Diana E. Trevino

Theses and Dissertations - UTB/UTPA

Staphylococci from part of the natural flora of humans and some, like Staphylococcus aureus, appear to be evolving antibiotic resistance. The Lower Rio Grande Valley (LRGV) is an area of interest due to its proximity to the US/Mexico border where antibiotics could recently be purchased without prescription. Two libraries from community association (CA-S) and environmental association (E-S) have been collected and the staphylococci isolated. We hypothesize that their SCCmec type, which aids the staphylococci in antibiotic resistance, will not display classically defined association schemes and will surface in many species of staphylococci. This study generates antibiotic resistance profiles via antibiotic …

A Moderate Elevation Of Circulating Levels Of Igf-I Does Not Alter Erbb2 Induced Mammary Tumorigenesis, Robert K. Dearth, Isere Kuiatse, Yu-Fen Wang, Lan Liao, Susan G. Hilsenbeck, Powel H. Brown, Jianming Xu, Adrian V. Lee

Biology Faculty Publications and Presentations

Background

Epidemiological evidence suggests that moderately elevated levels of circulating insulin-like growth factor-I (IGF-I) are associated with increased risk of breast cancer in women. How circulating IGF-I may promote breast cancer incidence is unknown, however, increased IGF-I signaling is linked to trastuzumab resistance in ErbB2 positive breast cancer. Few models have directly examined the effect of moderately high levels of circulating IGF-I on breast cancer initiation and progression. The purpose of this study was to assess the ability of circulating IGF-I to independently initiate mammary tumorigenesis and/or accelerate the progression of ErbB2 mediated mammary tumor growth.

Methods

We crossed heterozygous …

Phylogenetic Analysis Of Serine Proteases From Russell's Viper (Daboia Russelli Siamensis) And Agkistrodon Piscivorus Leucostoma Venom, Pattadon Sukkapan, Ying Jia, Issarang Nuchprayoon, John C. Pérez

Biology Faculty Publications and Presentations

Serine proteases are widely found in snake venoms. They have variety of functions including contributions to hemostasis. In this study, five serine proteases were cloned and characterized from two different cDNA libraries: factor V activator (RVV-V), alpha fibrinogenase (RVAF) and beta fibrinogenase (RVBF) from Russell's viper (Daboia russelli siamensis), and plasminogen activator (APL-PA) and protein C activator (APL-C) from Agkistrodon piscivorus leucostoma. The snake venom serine proteases were clustered in phylogenetic tree according to their functions. KA/KS values suggested that accelerated evolution has occurred in the mature protein coding regions in cDNAs of snake venom …

Monitoring Atrazine-Degrading And Atrazine-Tolerant Bacterial Populations In Lower Rio Grande Valley Agricultural Canals Using Quantitative-Pcr And Internal Atza Primers, Ibdanelo Cortez

Theses and Dissertations - UTB/UTPA

The research hypothesis was that atrazine-degrading bacteria would be detectable during the planting and rainy seasons with their populations dissipating during non-planting and dry seasons in 2010-2011. Atrazine concentration was detected in March, May, June and August for all canals with June having the highest average concentration of 0.77ppb. Gene atzA abundance was detected from June through August with July samples having the highest gene abundance of 250.6 (pg). Tolerant bacterial densities were detectable from March through June. Atrazine concentration and population abundance were not statistically different during planting and non-planting, rainy and dry seasons, although there was a trend …

Comparison Of Soil Chemistry And Microbial Communities That Inhabit The Rhizosphere Of Native And Non-Native Grasses Of The Lower Rio Grande Valley, Jacqueline Valencia

Theses and Dissertations - UTB/UTPA

Non-native grasses can modify the soils they invade. This study investigated microbial variation among native and non-native grasses in the Lower Rio Grande Valley. We hypothesized that rhizospheres of non-native grasses would support a higher density of microorganisms; therefore microbial communities of invasive plants would exploit more carbon sources than those of native plants. A second hypothesis stated that Streptomyces bacteria from the rhizosphere of non-native grasses would be better competitors. Samples of grasses, and soil from their respective rhizospheres were obtained in Arroyo City, TX. Results indicated a higher bacterial colony density, total activity and number of substrates utilized …

Color Polymorphism Of Sand Crabs, Lepidopa Benedicti (Decapoda: Anomura: Albuneidae), Unnam Nasir, Zen Faulkes

Biology Faculty Publications and Presentations

Sand crabs (Lepidopa benedicti) are highly specialized digging animals that spend the vast majority of their adult life submerged in fine sand. The carapace color of L. benedicti varies from gray to white. Given that the environment in which they live is uniform and dark, most of the functional scenarios to explain color variation seem unlikely to apply. Carapace color has a bimodal distribution, indicating that it is better characterized as a polymorphism than simply as normal variation. Gray crabs are larger and more common than white ones. Crabs mostly swim ventral-side up, which suggests that countershading does …

Effects Of Leaf Excision And Sample Storage Methods On Spectral Reflectance By Foliage Of Giant Reed, Arundo Donax, Kenneth R. Summy, Jonathan Lieman, Yuridia Patricia Gandy, Adarsh Mamachen, Ashish Mamachen, John A. Goolsby, Patricia J. Moran

Biology Faculty Publications and Presentations

Research was conducted to evaluate the effects of leaf excision and sample storage methods on spectral reflectance by foliage of giant reed, Arundo donax, an invasive weed which has caused extensive damage in many areas of the Rio Grande Basin in Texas and Mexico. Within 24 hours of excision, A. donax leaves exposed to ambient laboratory conditions (room temperature under natural lighting conditions) exhibited two trends indicative of physiological stress: 1) small but significant increases in reflectance of blue and red wavelengths (400-500 nm and 600-700 nm, respectively) and 2) a substantial reduction in reflectance of near-infrared (NIR) wavelengths (700-1,100 …

Techniques To Facilitate The Acquisition Of Accurate Spectral Measurements And Multispectral Imagery Of Plant Foliage Under Artificial Lighting Conditions, Yuridia Patricia Gandy, Ashish Mamachen, Adarsh Mamachen, Jonathan Lieman, Michael W. Persans, Jason Parsons, Elamin E. Ibrahim, James H. Everitt, Christopher R. Little, Kenneth R. Summy

Biology Faculty Publications and Presentations

Spectral measurements obtained in the laboratory under artificial lighting sources have been used for many years to develop spectral ‘libraries’ for various soil types, rocks and minerals, and other inanimate features occurring on or near the earth’s surface. Quartz halogen lamps have been shown to emit all of the electromagnetic (EMR) wavelengths required for the acquisition of quality multispectral imagery, and various techniques have been developed to facilitate the acquisition of accurate spectral measurements using such artificial lighting sources. Our objectives in this study were to evaluate the several factors of critical importance in obtaining accurate spectral measurements for plant …

A Phylogenetic Assessment Of Breeding Systems And Floral Morphology Of North American Ipomoea (Convolvulaceae), J. Andrew Mcdonald, Joshua R. Mcdill, Debra R. Hansen, Beryl B. Simpson

Biology Faculty Publications and Presentations

A phylogenetic investigation of 68 species and two varieties of tropical and temperate North American Ipomoea (Convolvulaceae) using sequence data from the internal transcribed spacer region (ITS) with parsimony and Bayesian analyses revealed multiple origins of autogamy. By assessing breeding systems and floral morphological characters in the context of this phylogeny, we estimate 16 independent origins of autogamy and 4 subsequent reversions to xenogamy. Transitions to autogamy are associated with reduced pollen-ovule ratios, decreased anther-stigma distance, and small flower size. Although the relationship between floral traits and breeding systems has been described in previous studies, this is the first investigation …