Biology Commons^™

A Natural Antimicrobial From Bacillus Subtilis As A Biosanitizer For Resilient Membrane Biofilms, Pratishtha Verma

Electronic Theses and Dissertations

The microbial attachment and colonization on separation membranes lead to biofilm formation. Some selective isolates within the biofilm constitutive microflora acquire resistance and emerge predominant over prolonged use of the membrane. Thus, proving the cleaning and sanitization protocols to be ineffective in adequately removing resilient biofilms. This subsequently leads to selecting microbial resistance within the constitutive microflora to almost all antimicrobial treatments and hence, creates a need to develop novel alternative strategies to control biofilm formation on membrane surfaces. The first research project under this study was designed to understand the microbial interactions and emergence of predominance within biofilm constitutive …

Interaction Of Streptomyces Closely Associated With Bacillus In Nitrogen-Limiting Conditions, Aminya Baniya

Electronic Theses and Dissertations

Biological Nitrogen Fixation is the process of conversion of atmospheric dinitrogen into ammonia which is performed by symbiotic as well as free-living diazotrophic bacteria. A previous project to isolate free-living nitrogen fixing bacteria from a natural prairie yielded Streptomyces which grew on nitrogen free medium. Genome sequencing of three isolates revealed the presence of a second 16S rRNA gene sequence aligning with Bacillus, however repeated streaking only yielded Streptomyces colonies. The aim of this research was to characterize the interaction of three Streptomyces isolates that grow under nitrogen-free conditions, and appeared to be associated with Bacillus. The separation of Bacillus …

Development Of Methods To Improve Lactose Recovery From Permeate And Drying Characteristics Of Greek Acid Whey, Venkateswarlu Sunkesula

Electronic Theses and Dissertations

Growth of higher protein dairy products and ingredients such as cheese, Greek yogurt, whey protein concentrates, and milk protein concentrates is limited by the amount of co-product generated and the ability to process them into value added ingredients. Finding value for all the co-products will help dairy industry to meet the growing demand for dairy protein products and ingredients. Commercial scale evaluation of new technologies for improving lactose crystallization and drying ability of Greek yogurt acid whey will help dairy industry to better utilize different dairy co-products. Commercially, lactose is manufactured from concentrated permeate by cooling and separating α-lactose monohydrate …

Investigating Links Between Soil Microbial Structure And Function In Three Major Plant Communities Across Temporal Scales Of Arctic Alaska, Kaj Lynoe

Electronic Theses and Dissertations

Arctic microbial systems continue to get attention today as our understanding regarding their structure and function in a changing system is paramount to C feedbacks with warming and changes in precipitation. Plant communities and microbial community processes across the Arctic landscape are central to understanding tundra ecosystem processes because environmental conditions and plant community structure drive microbial cycling of soil organic matter. Here, we want to understand how soil microbial respiration, mineralization, biomass, and community composition are linked to three Alaskan tundra plant communities, namely Shrub, Tussock, and Sedge tundra and the seasonal variability in this system. A total of …

Exploring The Properties Of Chitin For Promoting Tissue Engineering And Repair, M. Jahir Raihan

Electronic Theses and Dissertations

No abstract provided.

Fishes Of The Dakotas, Kathryn Schlafke

Electronic Theses and Dissertations

Biological reference materials play a critical role in studies of species biodiversity, biology, distribution, and historic diversity. Since the publications Fishes of North Dakota (Hankinson, 1929) and Fishes of South Dakota (Bailey and Allum, 1962), no new books have attempted to update the knowledge gained from the past decades of fish surveys and incorporate georeferenced collections at the state level. The last published book with the most complete accounts of fishes from North Dakota and South Dakota is the Distribution of Fishes in North and South Dakota Basins affected by the Garrison Diversion Unit (Owen et al. 1981) which includes …

Analysis Of Two Maize Mutations That Arose After Exposure To Radiation From A Plutonium-Beryllium Source And Developing Molecular Markers For Antimorph Aei1-5180, An Alternative To Aei To Increase Amylose Content In Maize Endosperm, Prameela Awale

Electronic Theses and Dissertations

This thesis consists of two independent projects dealing with two different aspects of maize. The first project is about the maize reproduction, where we try to uncover the candidate genes of two mutations that affect pollen viability and successful fertilization. The second project is about maize endosperm starch, where we developed molecular markers to characterize a mutant allele that knocks a major starch branching enzyme in maize.

Analysis of two maize mutations that arose after exposure to radiation from a plutonium-beryllium source
Maize is a monoecious and diclinous plant. Sexual reproduction takes place by the fusion of haploid male and …

Utilizing Rhizospheric And Bacterial Endophytes For Use As Potential Bio-Fertilizers For Sustainable Agricultural Production, Vincent Peta

Electronic Theses and Dissertations

Brassica carinata crop production offers an exciting alternative approach to the energy crisis when looking at novel ways to power our motor vehicles. Bacterial endophytes, while residing in host-plant tissues, offer a wide array of plant growth promotion benefits such as nitrogen fixation to impart nitrogen (N) nutrition, phosphate (P) solubilization to make soil-bound phosphate more mobile in soil for plant uptake, can suppress pathogenic microbes such as fungus and produce plant growth hormones to offset stress incurred by the plant. Previous literature has shown that there is large interest in studying endophytes from economically important crops such as wheat, …

Crispr/Cas9 Whole Genome Screens Reveal Novel Regulators Of Endocytic Processes In Macrophages, Jared Wollman

Electronic Theses and Dissertations

Macrophages maintain tissue homeostasis by identifying and eliminating threats within their tissue microenvironment. Pattern recognition receptors allow macrophages to recognize and internalize specific ligands while macropinocytosis allows the internalization of all extracellular solutes from their environment. Without pattern recognition receptors, pathogens may grow unchecked if they cannot be detected, and without macropinocytosis, macrophages struggle to detect and move around their environment. This thesis presents the results of CRISPR/Cas9 whole-genome screens used to identify the regulators of both endocytosis (Chapter 2) and macropinocytosis (Chapter 3). In Chapter 2, we report genes regulating dextran uptake in primary murine macrophages and reveal Mrc1-mediated …

Genetic Study Of Alkane Production And Oxic Nitrogen Fixation In Anabaena Sp. Pcc 7120, Jaimie L. Gibbons

Electronic Theses and Dissertations

Anabaena sp. PCC 7120 is a filamentous, nitrogen-fixing cyanobacterium that uses spatial separation to perform photosynthesis and nitrogen fixation simultaneously. Under fixed nitrogen limiting conditions, Anabaena 7120 forms specialized cells, called heterocysts, to fix nitrogen. In this research, I sought to add to the knowledge surrounding the process of heterocystous nitrogen fixation in Anabaena 7120. Cyanobacteria universally produce alkanes, which have been suggested to play a role in helping the organism adapt to abiotic stress, such as diazotrophic conditions. In my first study, I sought to identify the genes required for production of the hydrocarbon heptadecane (C17H36). Through using a …

Actin Regulation And Furrow Dynamics During Early Drosophila Embryogenesis, Yi Xie

Electronic Theses and Dissertations

Drosophila embryogenesis starts with a single nucleus undergo 13 rounds of nuclear divisions called syncytial cycles. Staring at cycle 10 when nuclei migrate to the surface of the embryo, massive and dynamic cortical actin structures and cleavage furrow formations occur. How actin regulators coordinate into an organized network directing three-dimension actin structures in the developing organisms is an unsolved question. Here, I present an in-depth characterization of actin cap dynamics: the actin caps go through expansion, stabilization, elongation and fragmentation phases in each cycle. Arp2/3 is the major contributor to actin cap formation. The functions of 7 different actin and …

Role Of Topoisomerase Ii Alpha In Dna Topology And T Cell Responses During Chronic Viral Infections, Stella Chinyere Ogbu

Electronic Theses and Dissertations

The clearance of viruses is largely dependent upon the activation of T cells to generate a robust immune response. However, host responses are suppressed during chronic viral infections. In this thesis, we explored the role of Top2α in DNA topology in individuals with chronic HBV, HCV, and HIV infections. We found that Top2α protein expression and activity were low in T cells derived from chronically virus-infected individuals compared to healthy subjects. Using CD4⁺ T cells treated with Top2α inhibitor or poisoner as a model, we demonstrated that Top2α inhibition disrupts the DNA topology, suppresses DNA repair kinase (ATM), and …

Age And Seasonal Change In The Chronobiology Of A Spider With An Exceptionally Long-Period Circadian Clock, Shae Crain

Electronic Theses and Dissertations

This study examines locomotor activity in samples of Frontinella pyramitela collected over its active season (April-October) to investigate whether seasonality and/or age may help explain the exceptional variability typically found in spider clock systems. Despite its noteworthy variability (%CV= 7.7), we have found that Frontinella has a mean free-running period of 28.4±2.18 hours that does not significantly vary over time. There is no correlation between day length and free-running period, indicating that varying length of FRP is not a function of photoperiod length. In LD 12:12 h, the window of activity is significantly smaller in April, gradually widening as the …

Understanding Object Motion Encoding In The Mammalian Retina., Victor Julian Depiero

Electronic Theses and Dissertations

Phototransduction, transmission of visual information down the optic nerve incurs delays on the order of 50 – 100ms. This implies that the neuronal representation of a moving object should lag behind the object’s actual position. However, studies have demonstrated that the visual system compensates for neuronal delays using a predictive mechanism called phase advancing, which shifts the population response toward the leading edge of a moving object’s retinal image. To understand how this compensation is achieved in the retina, I investigated cellular and synaptic mechanisms that drive phase advancing. I used three approaches, each testing phase advancing at a …

Osmoregulation And Salinity Preference In Juvenile Sandbar Sharks (Carcharhinus Plumbeus) In Winyah Bay, Sc, Usa, Jessica Wingar

Electronic Theses and Dissertations

Juvenile sandbar sharks (Carcharhinus plumbeus) have been caught in salinities ranging from 7 – 40. In Winyah Bay, a partially mixed estuary in Northeast SC, juvenile sandbar sharks tidally alternate between higher tides in middle bay and lower tides in lower bay. To assess salinity preference and duration in eight acoustically-tagged juvenile sandbar sharks in different salinities, acoustic receivers with salinity loggers were placed throughout Winyah Bay. Juvenile sandbar sharks were caught in salinities from 17.2 to 36.1 and acoustic detections were recorded from 11.5 to 24.7 by salinity loggers in middle bay. Smaller juvenile sandbar sharks used lower salinities, …

The Effects Of Urbanization On Avian Seed Dispersal Success Of Toxicodendron Radicans (Anacardiaceae), Aiden M. Stanley

Electronic Theses and Dissertations

Urbanization is increasing at a dramatic rate as the human population increases. While it is well-known that urbanization tends to decrease species diversity (i.e., biotic homogenization), it is not known how urbanization affects the frequency and efficiency of species interactions. Seed dispersal is a plant-animal interaction that depends on disperser feeding rate, disperser diversity, probability of seed dispersal and germination. How these factors are affected by urbanization however is unknown. In this study, we evaluate how urbanization alters these factors. Urban sites had 2x higher feeding rate and 3x higher number of disperser species. The probability of seed dispersal however …

Does Thermotolerance In Daphnia Depend On The Mitochondrial Function?, Rajib Hasan

Electronic Theses and Dissertations

Thermotolerance limit in aquatic organism is set by the ability to sustain aerobic scope to sudden temperature shifts. This study tested the genetic and plastic differences in thermotolerance of Daphnia that can be explained by the differences in the ability to retain mitochondrial integrity at high temperatures. Five genotypes with different biogeographic origins were acclimated to 18^ᵒC and 25^ᵒC. We developed a rhodamine 123 in-vivo assay to measure mitochondrial membrane potential and observed higher fluorescent in heat damaged tissues as the disruption of the mitochondrial membrane potential. Significant effects on temperature tolerance were observed with CCCP …

Transforming Moss P. Patens With Lignin Peroxidase Through Heterologous Protein Expression., Jesse Lee Rozsa

Electronic Theses and Dissertations

Lignin peroxidase is an enzyme secreted by white-rot fungi Phanerochaete chrysosporium. Our laboratory is attempting to produce several lignin degrading enzymes in our protein expression system that utilizes the moss, Physcomitrella patens. During our experiments we discovered that this particular species of fungus produces altered splicing variants that are not represented in the previously reported reference sequence. Despite several attempts to produce a positive transformant containing a desired transgene encoding; lignin peroxidase, production of the proper construct eluded our efforts, possibly due to toxic effects associated with lignin peroxidase expression. Our laboratory has created a stepping stone for other laboratories …

Microplastics In The Digestive System Of The Atlantic Sharpnose Shark (Rhizoprionodon Terraenovae) In Winyah Bay, Sc, Elise Virginia Pullen

Electronic Theses and Dissertations

The digestive tracts and livers of adult male Atlantic sharpnose sharks (N=16), Rhizoprionodon terraenovae, from Winyah Bay, South Carolina were examined for ingested microplastics. R. terraenovae is a small, locally abundant, coastal mesopredatory elasmobranch belonging to the family Carcharhinidae. Microfibers comprised the largest categories of plastics (94% of the total), and were found in 100% of sharks examined. The number of micro- and other plastics ranged from 34 to 75 per individual and totaled 927. The majority of plastics (40%) were blue in coloration, and 55% were <1 mm in length. Microplastics were observed on both the interior and exterior of the organs examined, and three microfibers were embedded within the stomach lining, an observation not previously reported in marine vertebrates and one which represents a potential pathway for the translocation of ingested microplastics.

Pine, Aphids, And Parasitoid Wasps: Patterns Of Cospeciation And Host Switches In A Tri-Trophic System, Amber Bass

Electronic Theses and Dissertations

Ecological interactions may drive speciation events, and the processes that drive these speciation events can leave behind patterns in the phylogenies of interacting taxa. These patterns have been studied extensively in herbivores and host plants, as well as parasites and their hosts, but rarely in tri-trophic systems. Here, we examine three closely related groups of interacting taxa, including parasitoid wasps (Pauesia), aphid herbivores (Cinara), and pine trees (Pinus) to determine if the patterns between each interacting taxa indicate that cospeciation or host switches are more dominant. We create phylogenies of Cinara and Pauesia in the southeastern United States using ddRADseq …

Do Per-Capita Impact Or Abundance Dominate The Impact Of An Invader? Interactions Among Neighboring Species In Context-Dependent Competition, Haoyu Li

Electronic Theses and Dissertations

Evaluating relative species competitive strength is a central question in community ecology, with strong implications for invasion ecology. Models assessing invader success consider three components: distribution, abundance and per-capita impact. However, relative strength and interactions among these factors remain unclear when applying to specific invasion scenarios. We hypothesized that performance of native and non-native species will vary as a function of direct and indirect effects at different abundances and scales. We conducted a replacement experiment between two dominant grasses in subtropical grasslands (the native Axonopus fissifolius and the non-native Paspalum notatum) in central Florida, USA. Thirty fenced plots (1 m …

Preparation Of A Flavonol Specific Glucosyltransferase Found In Grapefruit And Site-Directed Mutants For Protein Crystallization, Aaron Birchfield

Electronic Theses and Dissertations

This research was designed to determine the conditions necessary to remove c-myc and 6x-His tags from a flavonol specific glucosyltransferase found in grapefruit (CP3GT) using thrombin in preparation for crystallization. X-ray crystallography of CP3GT crystals may elucidate structural features that account for flavonol specificity in some glucosyltransferase enzymes. A thrombin cleavage site was inserted into WT CP3GT and one mutant. Recombinant CP3GT was expressed in yeast and purified. Optimal conditions for thrombin digestion were explored. Digestion with 100U of thrombin for 2 hours at 4^o C was optimal for removing tags from CP3GT. Storage at 4^o C for …

Differentiating Black Bears (Ursus Americanus) And Brown Bears (U. Arctos) Using Linear Tooth Measurements And Identification Of Ursids From Oregon Caves National Monument, Emily Bogner

Electronic Theses and Dissertations

North American black bears and brown bears can be difficult to distinguish in the fossil record due to similar dental and skeletal morphologies. Challenges identifying ursid material from Oregon Caves National Monument (ORCA) called for an accurate tool to distinguish the species. This study utilized a large database of lower tooth lengths and ratios in an attempt to differentiate black and brown bears in North America. Further, this project examined how these linear measurements differ geographically. Analysis of variance (ANOVA) found significant differences between black and brown bears from across North America for every variable studied. Stepwise discriminant analyses (DA) …

Biogeochemical Effects Of Sea Level Rise-Induced Transitions Within Coastal Wetlands, Havalend Steinmuller

Electronic Theses and Dissertations

As sea level rise (SLR) affects coastal wetlands, ecosystem responses can include vertical accretion, landward transgression, or submergence. Sea level rise-induced transitions can alter key biogeochemical transformations within wetland soils, impacting the ability of these systems to provide ecosystem services, specifically carbon (C) storage and water quality regulation. Through a series of complementary laboratory and field-based studies, biogeochemical responses to salinity, vegetation shifts, and submergence were investigated. Changes in nutrient dynamics associated with saltwater intrusion were evaluated by artificially adding saline water to different freshwater wetland soil types, indicating that potential exports of critical nutrients (forms of nitrogen, phosphorus, and …

Defects In Fetal Mouth Movement And Pharyngeal Patterning Underlie Cleft Palate Caused By Retinoid Deficiency., Regina Friedl

Electronic Theses and Dissertations

Cleft palate is a common birth defect. Etiologic mechanisms of palate cleft include defects in palate morphogenesis, mandibular growth, or spontaneous fetal mouth movement. Cleft palate linked to deficient fetal mouth movement has been demonstrated directly only in a single experimental model of loss of neurotransmission. Here, using retinoid deficient mouse embryos, we demonstrate directly for the first time that deficient fetal mouth movement and cleft palate occurs as a result of mis-patterned development of pharyngeal peripheral nerves and cartilages. Retinoid deficient embryos were generated by inactivation of retinol dehydrogenase 10 (Rdh10), which is critical for production of …

Characterization Of Vps41 And Its Role In The Regulated Secretory Pathway, Christian Henry Burns

Electronic Theses and Dissertations

Insulin secretory granules (SGs) mediate the regulated secretion of insulin, which is essential for glucose homeostasis. The basic machinery responsible for this regulated exocytosis consists of specific membrane proteins present both at the plasma membrane and on insulin SGs. The protein composition of insulin SGs thus dictates their release properties, yet the mechanisms controlling insulin SG formation, which determines this molecular composition, remain poorly understood. VPS41, a component of the endolysosomal tethering HOPS complex, was recently identified as a cytosolic factor involved in the formation of neuroendocrine/neuronal granules. We now find that a stable pool of VPS41 exists outside of …

Qualitative And Quantitative Fitness Consequences Of Advanced Maternal Age, Claudia Jean Hallagan

Electronic Theses and Dissertations

Parental age can affect offspring fitness across taxa and through various mechanisms. However, the effect(s) of advanced maternal age on offspring, particularly in insects, has not been comprehensively reviewed making it difficult to draw conclusions about the effects of advanced maternal age on offspring in insects. In my first chapter, I reviewed maternal age literature and found overall negative effects of advanced maternal age on offspring fitness. However, results vary depending on which fitness measures were used, the life stages at which offspring were measured, and the experimental design of the study. In my second chapter, I conducted an experiment …

Examining The Role Of Reproductive Interference In The Decline Of Native Green Treefrogs Following Cuban Treefrog Invasions, Joseph Kennedy

Electronic Theses and Dissertations

Reproductive interference occurs when the mating behaviors of one species negatively impact the fitness of another species. It is of increasing interest in invasive species biology because the introduction of alien species often leads to novel sexual interactions with native taxa, which can contribute to their decline. I examined whether reproductive interference plays a role in the decline of native green treefrogs (Hyla cinerea) following invasions of Cuban treefrogs (Osteopilus septentrionalis) in the southeastern United States. The impetus for this study revolves around similarities in spectro-temporal features of Cuban treefrog courtship calls and green treefrog aggressive calls. The significance of …

Identifying Transcription Co-Regulators Of Gcm/Repo In The Development Of Glia In Drosophila Melanogaster, Glendin Kostantinos Pano

Electronic Theses and Dissertations

The molecular mechanism mediating the differentiation of neural progenitors to either glia or neurons is guided by the gene glial cells missing (gcm), a master regulator of glial cell differentiation. Knockout of this transcription factor (TF) and its homolog gcm2 in the fruit fly Drosophila Melanogaster results in embryos that develop neurons in place of lateral glia. Conversely, overexpression of gcm in those neural progenitors results in embryos that have substantially fewer neurons and excess glia(Jones, et.al, 1995; Hosoya, et.al, 1995; and Vincent, et.al, 1996). Additionally, gcm has also been shown to be involved in the differentiation of blood …

Influence Of Sporulation And Germination Behavior Of Bacillus Licheniformis On Microbial Quality Of Skim Milk Powder, Nancy Awasti

Electronic Theses and Dissertations

This dissertation includes modeling of sporulation and germination behavior of Bacillus licheniformis strains during raw milk holding, tracking the survival of sporeformers and spores of high sporulating Bacillus strain during skim milk powder manufacturing. In addition, preliminary studies were done to standardize a rapid spore detection technique by using ratiometric fluorescence. To understand the role of strain variability during raw milk holding conditions, population dynamics of two strains of Bacillus licheniformis, ATCC 6634 and 14580, were modeled as a function of temperature (4.0 -12.0˚ C) and duration (0 - 72 h), using regression analysis. Based on initial spiking of vegetative …