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Full-Text Articles in Life Sciences

Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine, Ada Duka Jan 2013

Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine, Ada Duka

UNF Graduate Theses and Dissertations

Glucose is transported in crustacean hepatopancreas and intestine by Na+-dependent co-transport, while Na+-dependent D-fructose influx has only been described for the hepatopancreas. It is still unclear if the two sugars are independently transported by two distinct cotransporter carrier systems. In this study lobster (Homarus americanus) hepatopancreas brush border membrane vesicles (BBMV) were used to characterize, in detail, the cation-dependency of both D-[3H] glucose and D-[3H] fructose influxes, while in vitro perfused intestines were employed to determine the nature of cation-dependent sugar transport in this organ. Over the sodium concentration range of 0-100 mM, both ...


Nutrient Availability Affects Flowering Rate But Has Limited Influence On Morphology Of The Hooded Pitcher Plant, Sarracenia Minor., Justin M. Lemmons Jan 2013

Nutrient Availability Affects Flowering Rate But Has Limited Influence On Morphology Of The Hooded Pitcher Plant, Sarracenia Minor., Justin M. Lemmons

UNF Graduate Theses and Dissertations

Carnivorous plants perform as both producers and consumers. Botanical carnivory has evolved in sunny, moist, nutrient-poor environments, and the primary nutrient supplied by prey is proposed to be nitrogen. There is a trade-off between carnivorous and photosynthetic structures which corresponds to degree of carnivory expression and available nutrients. This study was conducted on the hooded pitcher plant, Sarracenia minor, which is a facultative wetland plant and Florida-threatened species. Sarracenia minor is considered a specialist myrmecophage and ants characterize the majority of attracted and captured prey. Ants not only provide nutritional benefit, but also protection against herbivory. A natural population of ...


Impact Of Nutritional Status On The Somatotropic Axis And Ghrelin In Phocid Seals, Rachael Dailey Jan 2013

Impact Of Nutritional Status On The Somatotropic Axis And Ghrelin In Phocid Seals, Rachael Dailey

UNF Graduate Theses and Dissertations

Metabolic hormones and their axes, including the target tissues and receptors, regulate the tissue specific utilization of nutrients with in the body. The purpose of this research was to understand the hormonal control of complex nutrient partitioning mechanisms involved in young, growing animals. Specifically, this involved the investigation of metabolic hormones and the regulation of growth in two common species of phocids (true seals): harbor seal (Phoca vitulina) and Northern elephant seal (Mirounga angustirostris) pups. This longitudinal study examines young phocids from nutritional nadir through realimentation (realimentation) to investigate how metabolic hormones involved in both food intake and nutrient partitioning ...


Arbovirus Persistence And Selection Of Persistent Variants Following Chronic Infection In Aedine Mosquitoes: A Comparative Study Between Ae. Aegypti And Ae. Albopictus 30 Days Post Infection With Sindbis Virus, Zoe Leah Lyski Jan 2013

Arbovirus Persistence And Selection Of Persistent Variants Following Chronic Infection In Aedine Mosquitoes: A Comparative Study Between Ae. Aegypti And Ae. Albopictus 30 Days Post Infection With Sindbis Virus, Zoe Leah Lyski

UNF Graduate Theses and Dissertations

In the present investigation two container breeding mosquitoes, Aedes aegypti and Aedes albopictus were exposed to Sindbis virus (SINV). Mosquitoes were proffered a viremic bloodmeal using a vertical membrane feeder in an attempt to infect females while preserving virus-gut interactions that are speculated to be responsible for amplification and selective roles encountered in nature. Cohorts of 50 mosquitoes of each species were exposed to SINV strain TR339 or EMEM in a bloodmeal and incubated in insectary conditions for 30 days. Once infected, the mosquito remains persistently infected for life, accumulating mutations in the virus RNA genome. Plaque size variants may ...


Bacteriostatic Effects Of Sucralose On Environmental Bacteria, Arthur Phillip Omran Jr. Jan 2013

Bacteriostatic Effects Of Sucralose On Environmental Bacteria, Arthur Phillip Omran Jr.

UNF Graduate Theses and Dissertations

Sucralose is a zero calorie sweetener developed and manufactured by Tate and Lyle Sweetener Company in the 1980’s. They sell the sweetener compounded with maltodextrin and dextrose under the brand name Splenda®. Sucralose was developed as a low cost artificial sweetener that is non-metabolizable in humans and can withstand changes in pH and temperature. It is not degraded by the waste water treatment process. Since the molecule can withstand heat, acidification and microbial degradation it is accumulating in the environment, and has been found in waste water, estuaries, rivers and the Gulf Stream. The highest concentration of environmental sucralose ...


The Effects Of Multiple Abiotic Stressors On The Susceptibility Of The Seagrass Thalassia Testudinum To Labyrinthula Sp., The Causative Agent Of Wasting Disease, Nichole Danielle Bishop Jan 2013

The Effects Of Multiple Abiotic Stressors On The Susceptibility Of The Seagrass Thalassia Testudinum To Labyrinthula Sp., The Causative Agent Of Wasting Disease, Nichole Danielle Bishop

UNF Graduate Theses and Dissertations

In the past century, seagrasses have experienced massive die off episodes in what has been collectively referred to as “wasting disease.” Researchers generally agree that wasting disease is caused by a protist of the Labyrinthula genus, and that environmental stressors can make some populations of seagrasses more susceptible to infection. The purpose of this study was to examine the combined effects of elevated salinity, elevated temperature, elevated sulfide and night-time hypoxia on Thalassia testudinum health and its response to Labyrinthula sp. infection under controlled conditions. To test these effects, microcosms were utilized and individual seagrass shoots were randomly assigned to ...


A Survey Of The Taxonomy Of The Cyanobacteria From Northeast Florida, Descriptions Of Novel Taxa, And An Investigation Into The Factors Which Influence The Epibenthic Cyanobacterial Community, Holly Stephanie Stocks Jan 2013

A Survey Of The Taxonomy Of The Cyanobacteria From Northeast Florida, Descriptions Of Novel Taxa, And An Investigation Into The Factors Which Influence The Epibenthic Cyanobacterial Community, Holly Stephanie Stocks

UNF Graduate Theses and Dissertations

Cyanobacteria are important components of the aquatic system, valued for their oxygen production, nitrogen fixation, and as the base of many aquatic food webs. This study investigated several aspects of cyanobacteria such as the diversity and response to nutrient enrichments. A survey of Northeast Florida was conducted between the years of 2010 and 2012; a total of 145 taxa were identified in freshwater habitats, such as springs, lakes, rivers, and retention ponds. While surveying the St. Johns River in Jacksonville, Florida, a novel Stigonematalean taxon was isolated and cultured. Subsequent morphological and genetic analyses indicate that this taxon is related ...


Plant-Pathogen Interactions Associated With Wasting Disease In The Tropical Seagrass Thalassia Testudinum., Kyle Loucks Jan 2013

Plant-Pathogen Interactions Associated With Wasting Disease In The Tropical Seagrass Thalassia Testudinum., Kyle Loucks

UNF Graduate Theses and Dissertations

Lipopolysaccharide (LPS) was shown to serve as a strong elicitor of the early defense response in the subtropical seagrass Thalassia testudinum Banks ex König and was capable of inducing an oxidative burst identified at the single cell level. The formation of reactive oxygen species (ROS) included a diphenylene iodonium sensitive response, suggesting the involvement of an NADPH oxidase. A 900 bp fragment of this enzyme was sequenced and found to encode a NAD binding pocket domain with extensive homology to the Arabidopsis thaliana rbohF (respiratory burst oxidase homolog) gene. Pharmacological dissection of the early events preceding ROS emission revealed that ...


Response Of The Epiphytic Algal Communities To Experimentally Elevated Nutrient Levels In Intertidal Salt Marsh Habitats, Stephanie Verhulst Jan 2013

Response Of The Epiphytic Algal Communities To Experimentally Elevated Nutrient Levels In Intertidal Salt Marsh Habitats, Stephanie Verhulst

UNF Graduate Theses and Dissertations

Epiphytes are organisms attached to plants and are responsible for the majority of primary productivity in many aquatic systems. While epiphytes serve as a valuable food resource to herbivores, they may prove deleterious to the host plant by competing for light and nutrients, as well as increasing sheer stress. This study evaluated the impacts of nutrient additions, nitrogen and phosphorus, on the epiphytic algal community on Spartina alterniflora over the course of two growing seasons. Three nutrient treatments (N, P, and N+P) and one control treatment were placed in a salt marsh in the Tolomato River during the growing ...


The Spacial And Temporal Community Structure Of Ichthyoplankton In A Northeast Florida Estuary : A Study Of Ingress At A Faunal Boundary, Breanna Korsman Jan 2013

The Spacial And Temporal Community Structure Of Ichthyoplankton In A Northeast Florida Estuary : A Study Of Ingress At A Faunal Boundary, Breanna Korsman

UNF Graduate Theses and Dissertations

Estuaries are widely recognized as important habitats for the early life history stages of commercially and recreationally important marine fish species. In general the estuaries of northeast Florida are understudied, and there is a need to characterize the ichthyoplankton community at this important faunal boundary between temperate and tropical marine zones. To determine community structure and temporal patterns in the distribution and abundance of larval fish ingressing in to the Guana-Tolomato-Matanzas (GTM) estuary through its two inlets (St. Augustine and Matanzas), ichthyoplankton were sampled bi-weekly for one year at both inlets during nighttime spring flood tides beginning in March 2012 ...


Physiological And Biochemical Responses Of Bald Cypress To Salt Stress, Nathan T. Lauer Jan 2013

Physiological And Biochemical Responses Of Bald Cypress To Salt Stress, Nathan T. Lauer

UNF Graduate Theses and Dissertations

Bald Cypress (Taxodium distichum (L.) Rich.) is native to freshwater wetlands of Florida. The vitality of cypress within coastal freshwater wetlands is threatened by saltwater intrusion. Biomarkers to detect sub-lethal salinity stress were developed using a controlled greenhouse study. Cypress saplings maintained at elevated salinities of 4 and 8‰ exhibited a decrease in maximum quantum yield (MQY) and an increase in non-photochemical quenching (NPQ). Cypress leaves exhibited an increase in Na+, H2O2, and free proline content compared to plants maintained in freshwater. These biomarkers were used to detect salinity stress within a population of cypress associated with ...


The Effects Of Thermal Stress And Algal Competition On The Early Life-History Stages Of Porites Astreoides And The Development Of Stress-Detecting Biomarkers For Use In Scleractinan Corals, Kevin C. Olsen Jan 2013

The Effects Of Thermal Stress And Algal Competition On The Early Life-History Stages Of Porites Astreoides And The Development Of Stress-Detecting Biomarkers For Use In Scleractinan Corals, Kevin C. Olsen

UNF Graduate Theses and Dissertations

Scleractinian coral populations are declining worldwide in response to numerous stressors operating on both global and regional scales. Rising sea surface temperatures associated with global climate change and the increasing frequency of coral-macroalgae competitive interactions are two of the gravest ecological drivers facing coral reef ecosystems. However, little is known about how these stressors interact to impact corals, their health, and potential modes of population recovery. These threats also highlight the need to develop reliable techniques that detect stress in multiple life-history stages of hermatypic corals prior to the degradation of coral reef habitats. To address these concerns we evaluated ...


Variations Of Ghrelin, Growth Hormone, And Insulin-Like Growth Factor I In The West Indian Manatee (Trichechus Manatus), Rachel Lynn Cimino Jan 2013

Variations Of Ghrelin, Growth Hormone, And Insulin-Like Growth Factor I In The West Indian Manatee (Trichechus Manatus), Rachel Lynn Cimino

UNF Graduate Theses and Dissertations

The metabolic hormones ghrelin, growth hormone, and insulin-like growth factor I are influenced by developmental age, sex, and nutritional status in domestic and free-ranging species. However the role these hormones play has not previously been explored in sub-tropical/ tropical mammals. Furthermore, the seasonality of species with less dynamic environmental cues, such as the West Indian manatee, have not been studied. The West Indian manatee is and endangered species distributed in the southeastern United States and throughout the Caribbean basin, and its nutritional physiology is influenced by environmental factors. Understanding the hormone response to nutritional status in this species and its ...


Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers, Alicia G. Linquist Jan 2013

Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers, Alicia G. Linquist

UNF Graduate Theses and Dissertations

Reduced reproduction has been shown to increase lifespan in many animals, yet the mechanisms behind this trade-off are mostly unknown. A previous study has shown that in the lubber grasshopper, Romalea microptera, ovariectomized (OVX) individuals have a 30% increase in lifespan relative to controls (Sham). In a separate study, an increase in fat body mass and a halting of ovarian growth were seen upon reduction of vitellogenin transcript via RNAi (VgRNAi). These data suggest that VgRNAi increases lifespan through the trade-off between reproduction and longevity and animals with combined ovariectomy and VgRNAi, might show additive physiological responses. In this study ...