Nancy Denslow

University of Florida | UF · Department of Physiological Sciences

Florida manatees (Trichechus manatus latirostris), a federally protected species, are classified as threatened due to anthropogenic stressors. Manatees inhabit sites that are impacted by human activities that can negatively affect stress physiology and metabolism. Samples collected from healthy manatees (pregnant females, non-pregnant females, and...

In addition to inhibiting renal glucose reabsorption and allowing for glucose excretion, the sodium/glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin may be efficacious in treating various comorbidities associated with type 2 diabetes mellitus (T2DM). The molecular mechanisms by which dapagliflozin exerts its beneficial effects are largely un...

Drinking water treatment residuals (DWTRs) are complex mixtures of organic and inorganic phases generally disposed of as waste materials. However, their strong sorptive properties could be further exploited to immobilize...

Hypertension may develop before or after the onset of diabetes and it is known to increase the risk of developing diabetic nephropathy. Alpha-1 antitrypsin (AAT) is a multi-functional protein with beneficial effects in various diseases but its role in reducing blood pressure in the diabetic kidney has not been thoroughly studied. Like blood pressur...

Hypertension remains a major problem, especially in the elderly, as it increases the risk for cardiovascular, coronary artery, cerebrovascular, and kidney diseases. Extracellular vesicles (EVs) play a role in the aging process and contribute to pathophysiology. Our goal was to examine differences in lipid profiles of urinary EVs (uEVs) collected du...

Ferroptosis is a druggable, iron-dependent form of cell death that is characterized by lipid peroxidation but has received little attention in lupus nephritis. Kidneys of lupus nephritis patients and mice showed increased lipid peroxidation mainly in the tubular segments and an increase in Acyl-CoA synthetase long-chain family member 4, a pro-ferro...

The C-type natriuretic peptide receptor (NPRC) is expressed in many cell types and binds all natriuretic peptides with high affinity. Ligand binding results in the activation or inhibition of various intracellular signaling pathways. Although NPRC ligand binding has been shown to regulate various ion channels, the regulation of endothelial sodium c...

Red tide events, caused by a toxin producing dinoflagellate, Karenia brevis, occur annually in Florida and Texas. These events lead to health risks for both humans and wildlife that utilize coastal environments. Brevetoxins, potent lipophilic neurotoxins produced by K. brevis, modulate immune responses in laboratory studies with model organisms and...

Herein, we report the toxicity evaluation of a new prototype dispersant system, silicon dioxide nanoparticles (NPs) functionalized with (3-glycidoxypropyl)triethoxysilane (GPS) and grafted poly(ε-caprolactone)-block-poly[oligo(ethylene glycol)methyl methacrylate mono-methyl ether] (NP-PCL-POEGMA). This serves as a follow up of our previous study wh...

Glyphosate is the most used herbicide worldwide, with no historical comparison. It is used for genetically modified crops, and particularly in Florida, it is used as a sugar cane ripener. An aquatic formulation (Rodeo®) is used to treat aquatic weeds in waterbodies and drainage canals. Because of its extended use, glyphosate can run off or be spray...

Bottlenose dolphins (Tursiops truncatus) are found in coastal and estuarine ecosystems where they are in continuous contact with multiple abiotic and biotic stressors in the environment. Due to their role as predators, they can bioaccumulate contaminants and are considered sentinel organisms for monitoring the health of coastal marine ecosystems. T...

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals commonly found in everyday consumer products and are an emerging concern due to their ubiquitous presence in ecosystems around the world. PFAS exposure, which often occurs through contaminated water, has been linked to several adverse health effects in humans and wildlife...

Salt-sensitive hypertension resulting from an increase in blood pressure after high dietary salt intake is associated with an increase in the production of reactive oxygen species (ROS). ROS are known to increase the activity of the epithelial sodium channel (ENaC), and therefore, they have an indirect effect on sodium retention and increasing bloo...

Endocrine disrupting chemicals (EDCs) are found in every environmental medium and are chemically diverse. Their presence in water resources can negatively impact the health of both human and wildlife. Currently, there are no mandatory screening mandates or regulations for EDC levels in complex water samples globally. Bioassays, which allow quantify...

Endocrine disrupting chemicals, such as bisphenol A (BPA) and ethinylestradiol (EE2), are detected in the marine environment from plastic waste and wastewater effluent. However, their impact on reproduction in sexually labile coral reef fish is unknown. The objective of this study was to determine impacts of environmentally relevant concentrations...

Transcriptomic information provides fundamental insights into biological processes and can be used to determine gene expression in cell, tissue, or organism under specific physiological conditions, or in response to any environmental perturbation. Extraction of high quality RNA is a challenging step mainly in non-traditional organisms, and protocol...

With increased usage of long-read sequencing technologies to perform transcriptome analyses, there becomes a greater need to evaluate different methodologies including library preparation, sequencing platform, and computational analysis tools. Here, we report the study design of a community effort called the Long-read RNA-Seq Genome Annotation Asse...

Given the opposing responses reported for bisphenol A (BPA) in terms of induction of obesogenic effects and impaired lipid metabolism, the increasing use of bisphenol F (BPF), and the relatively low information available regarding the effects of bisphenol A bis(3-chloro-2- hydroxypropyl) ether (BADGE·2HCl) in aquatic organisms, this work aims to us...

Extracellular vesicles (EVs) contain biological molecules and are secreted by cells into the extracellular milieu. The endothelial sodium channel (EnNaC) plays an important role in modulating endothelial cell stiffness. We hypothesized EVs secreted from human aortic endothelial cells (hAoEC) positively regulate EnNaC in an autocrine dependent manne...

Sea stars in research are often lethally sampled without available methodology to render them insensible prior to sampling due to concerns over sufficient sample quality for applied molecular techniques. The objectives of this study were to describe an inexpensive and effective two-step euthanasia method for adult common sea stars (Asterias rubens)...

Mosquito larvicides are an effective tool for reducing numbers of adult females that bite and potentially spread pathogenic organisms. Methionine, an essential amino acid in humans, has been previously demonstrated to be a highly effective larvicide against four (4) mosquito species in three (3) genera, Anopheles, Culex and Aedes. The aim of the pr...

The beneficial use of DWTRs faces barriers due primarily to uncertainties and concerns about their potential environmental impacts. In this study, we used total and water leachable toxic metal concentrations, and two benthic organisms based bioassays to identify suitable DWTR‐substrates for introduction to freshwater systems. Using total metal cont...

Estrogenic compounds are widely released to surface waters and may cause adverse effects to sensitive aquatic species. Three hormones, estrone, 17β-estradiol and 17α-ethinylestradiol, are of particular concern as they are bioactive at very low concentrations. Current analytical methods are not all sensitive enough for monitoring these substances in...

Drinking water treatment residuals (DWTRs) are multi-phase material byproducts from the coagulation, flocculation, and sedimentation processes used in conventional drinking water treatment. The reported high sorption capacity of DWTRs makes them promising candidates as capping materials for sediments contaminated with metals including copper. To un...

Florida manatees depend on freshwater environments as a source of drinking water and as warm-water refuges. These freshwater environments are in direct contact with human activities were glyphosate-based herbicides are being used. Glyphosate is the most used herbicide worldwide and it is intensively used in Florida as a sugarcane ripener and to con...

Two large-scale Florida manatee (Trichechus manatus latirostris) mortality episodes were reported on separate coasts of Florida in 2013. The east coast mortality episode was associated with an unknown etiology in the Indian River Lagoon (IRL). The west coast mortality episode was attributed to a persistent Karenia brevis algal bloom or ‘red tide’ c...

The preceding chapters have established that across taxa, neuroendocrine mechanisms are essential in regulating vocalization and a variety of other behaviors and systems. Consequently, all these tightly regulated systems are vulnerable to endocrine-disrupting chemicals (EDCs) in the environment. Given the abundance of evidence establishing that suc...

Carbon nanomaterials are emerging contaminants released into the environment primarily through anthropogenic processes, where they primarily partition into soils and sediments. Aquatic animals that inhabit, forage, or choose prey in...

Biomonitoring offers an appealing tool for the assessment of pollution in aquatic ecosystem. Biological processes, species, or communities of bioindicators are used to assess the quality of the environment and how it changes over time. Bioindicators include algae, macrophytes, zooplanktons, insects, bivalves, molluscs, gastropods, fish, amphibians,...

Oil spill accidents are a major concern for aquatic organisms. In recent history, the Deepwater Horizon blowout spilled 500 million liters of crude oil into the Gulf of Mexico. Corexit 9500A was used to disperse the oil since it was the method approved at that time, despite safety concerns about its use. A better solution is necessary for dispersin...

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus attacks multiple organs of coronavirus disease 2019 (COVID-19) patients, including the brain. There are worldwide descriptions of neurological deficits in COVID-19 patients. Central nervous system (CNS) symptoms can be present early in the course of the disease. As many as 55% o...

INTRODUCTION Extracellular vesicles (EVs) have been harvested from many plant sources, some of which have anti-cancer effects and some could be used as therapeutic nanodelivery vectors. Hemp plant is a natural source of cannabinoids, of which delta 9-tetrahydroxicannabinol (THC) and cannabidiol (CBD) have proven anti-cancer proprieties. HYPOTHESIS...

Toxaphene is an organochlorine pesticide and environmental contaminant that is concerning due to its atmospheric transport and persistence in soil. In Florida, toxaphene and other organochlorine pesticides were used heavily in agriculture on the north shore of Lake Apopka and they are still detectable in soil. Wild largemouth bass that inhabit the...

Aquatic organisms are exposed to multiple stressors in the environment, including contaminants and rising temperatures due to climate change. The objective of this study was to characterize the effect of increased temperature on chemical-induced toxicity and lipid profiles during embryonic development and hatch in fish. This is important because te...

Lipids play an essential role in development, homeostatic functions, immune signaling, reproduction, and growth. Although it is evident that changes in lipid biosynthesis and metabolism can affect organismal physiology, few studies have determined how environmental stressors affect lipid pathways, let alone alter global lipid profiles in fish. This...

During harmful algae blooms, the potential for exposure to aerosolized algal toxins is not well studied. A fundamental question remains over the longevity of algal toxins in the aerosol phase. In this study, the influence of environmental factors such as sunlight and atmospheric oxidants (e.g. ozone and OH radicals) on the lifetime of microcystin-L...

The potential for exposure to aerosolized algal toxins during harmful algal blooms has not been well studied. A fundamental question about the longevity of algal toxins in the aerosol phase remains. In this study, the influence of environmental factors such as sunlight and atmospheric oxidants (e.g., ozone and OH radicals) on the lifetime of microc...

To investigate a Florida manatee (Trichechus manatus latirostris) mortality event following a red tide bloom in Southwest Florida, an RNA sequencing experiment was conducted. Gene expression changes in white blood cells were assessed in manatees rescued from a red tide affected area (n = 4) and a control group (n = 7) using RNA sequencing. The gene...

Natural and synthetic steroid hormones, excreted by humans and farmed animals, have been considered as important sources of environmental endocrine disruptors. A suite of estrogens, androgens and progestogens was measured in the wastewater treatment plant outfall (WWTPO) of Chascomús city (Buenos Aires province, Argentina), and receiving waters loc...

Dichlorodiphenyldichloroethylene (DDE) and dieldrin are persistent pesticides that reside in surface waters and lakes around agricultural areas where previously these pesticides were heavily used. In this study, lipidomics using targeted LC-MS/MS was used to evaluate the effects of pesticides on fish.

Effective treatment of hypertension (HTN) in patients with diabetes may help to significantly reduce the risk of those patients developing additional complications including vascular disease and diabetic nephropathy. Blockers of the renin-angiotensin system including angiotensin converting enzyme inhibitors and angiotensin receptor blockers are not...

Cancer is the second leading cause of death worldwide, with 9.6 million cancer-related deaths in 2018. Cancer incidence has increased over time, and so has the prescription rate of chemotherapeutic drugs. These pharmaceuticals, known as antineoplastic agents, enter the aquatic environment via human excretion and wastewater. The objectives of the pr...

The diversity of anthropogenic impacts to coastal systems call for novel and "smart" indicators of anthropogenic contamination. Here, we have incorporated a suite of high-sensitivity techniques to assess anthropogenic contamination as part of the broader iCoast initiative. A 28 km transect was established in March 2019 to monitor the effects of sea...

Concerns about the presence of steroid hormones, including naturally occurring or synthetic hormones in rivers are increasing owing to their endocrine disrupting potentials. As part of the monitoring network of the iCoast project, surface waters were collected twice (May and June, 2019) from nine sites in the intracoastal stretch between Saint Augu...

Placental trophoblast cells are potentially at risk from circulating endocrine-disrupting chemicals, such as bisphenol A (BPA). To understand how BPA and the reputedly more inert bisphenol S (BPS) affect the placenta, C57BL6J mouse dams were fed 200 μg/kg body weight BPA or BPS daily for 2 wk and then bred. They continued to receive these chemicals...

Organochlorine pesticides (OCPs) are persistent environmental contaminants that act as endocrine disruptors and system toxicants. These pesticides (e.g. dichlorodiphenyltrichloroethane (DDT), dieldrin, toxaphene, among others) are ranked as some of the most concerning chemicals for human health. These pesticides (1) act as teratogens, (2) are neuro...

Toxaphene is a restricted-use pesticide produced by reacting chlorine gas with camphene. It was heavily used as a pesticide for agricultural purposes in the 1960-1970s, but despite being banned >30 years ago, it can remain elevated in the soil due to its resistance to metabolic degradation; this has led to longstanding concerns about elevated level...

In aquatic toxicology, perhaps no pharmaceutical has been investigated more intensely than 17alpha-ethinylestradiol (EE2), the active ingredient of the birth control pill. At the turn of the century, the fields of comparative endocrinology and endocrine disruption research witnessed the emergence of omics technologies, which were rapidly adapted to...

Estrogenic contaminants in the environment are linked to the occurrence of reproductive abnormalities in many aquatic species, including largemouth bass (Micropterus salmoides; LMB). Previous work has shown that many different types of xenoestrogens regulate expression of the Steroidogenic Acute Regulatory protein (StAR), a cholesterol-transporting...

Abstract Exosomes are nano‐sized vesicles that are involved in various biological processes including cell differentiation, proliferation, signaling, and intercellular communication. Urinary exosomes were isolated from a cohort of hereditary α‐tryptasemia (HαT) patients and from healthy volunteers. There was a greater number of exosomes isolated fr...

In recent decades, there has been a rise of endocrine-related diseases and disorders, including an increased incidence of genital anomalies, low semen quality, adverse pregnancy outcomes, neurobehavioral disruption, endocrine-related cancers, earlier onset of breast development, obesity, and type 2 diabetes (UNEP and WHO, 2013). An example of incre...

Glyphosate is the herbicide most used worldwide, with no historic comparison. It is used for genetically modified crops, and particularly in Florida, it is used as a sugar cane ripener. It also formulated to treat aquatic weeds in waterbodies as Rodeo®. Because of its extended used, it can run off or be sprayed directly into waterbodies and persist...

In contrast to mammals, the blood from vertebrates such as fish contains nucleated red cells. Using a fathead minnow (Pimephales promelas) oligonucleotide microarray, we compared altered transcripts in the liver and whole blood after Perfluoro Alkyl Substances (PFASs) exposure to elucidate the utility of using fish blood in aquatic toxicology studi...

Technological advances in molecular biology enable high-throughput screening (HTS) of large chemical libraries. These approaches have provided valuable toxicity data for many physiological responses, including mitochondrial dysfunction. While several quantitative structure-activity relationship (QSAR) models have been developed for mitochondrial dy...

Quality metrics for iTRAQ data and protein identification. (A) Ambiguity was assessed at both the level of protein. (B) The number of proteins that we quantified, quantified confidently, and the median log ratio for each iTRAQ label were assessed. (C) Correlations coefficients (r) between individual iTRAQ labeled samples are displayed.

Transcriptomics SNEA illustrating regulation of cell processes in the gut.

Proteomics SNEA results for regulation of cell processes in the liver.

Proteomics SNEA results for regulation of cell processes in the brain.

Primer sequences, sources, and efficiencies for qPCR analysis.

Transcriptomics SNEA illustrating regulation of cell processes in the telencephalon.

Transcriptomics SNEA illustrating regulation of cell processes in the hypothalamus.

Pairwise comparisons for differential transcript expression were made for each tissue; hypothalamus to telencephalon (A), hypothalamus to liver (B), liver to telencephalon (C), gut to telencephalon (D), gut to hypothalamus (E), and gut to liver (F). Black dots represent transcripts that were compared and red dots represent transcripts that were fou...

Transcriptomics SNEA illustrating regulation of cell processes in the liver.

Expression targets derived from Pathway Studio for gut, liver and brain. These are the genes highlighted in Figure 4.

Proteomics SNEA results for regulation of cell processes in the gut.

Omics approaches are broadly used to explore endocrine and toxicity-related pathways and functions. Nevertheless, there is still a significant gap in knowledge in terms of understanding the endocrine system and its numerous connections and intricate feedback loops, especially in non-model organisms. The fathead minnow (Pimephales promelas) is a wid...

Adverse outcome pathways (AOPs) are conceptual frameworks that organize and link contaminant-induced mechanistic molecular changes to adverse biological responses at the individual and population level. AOPs leverage molecular and high content mechanistic information for regulatory decision-making, but most current AOPs for hormonally active agents...

In recent years, decreases in fish populations have been attributed, in part, to the effect of environmental chemicals on ovarian development. Determining the molecular events underlying ovarian development is expected to contribute to the prevention of population decline in fish species by identifying the critical windows by which chemicals exert...

Phenols are classified as polar narcotics, which are thought to cause toxicity by non-specific mechanisms, possibly by disrupting membrane structure and function. Here we test three phenolic chemicals, phenol, 2,4-dichlorphenol and pentachlorophenol on embryo development, heartbeat rate and mitochondrial respiration in fathead minnow (Pimephales pr...

Chemical contaminants present in the environment can affect mitochondrial bioenergetics in aquatic organisms and can have substantial effects on individual fitness. As early life stages of fish are particularly vulnerable to environmental contaminants, they are ideal models for examining the relationship between impaired mitochondrial bioenergetics...

Addition of activated carbon to contaminated sediment is an established means of remediation but its applicability to sediments high in organic carbon is presently unknown. We evaluated the effects of adding either granular activated carbon (GAC) or pelletized fine-grained activated carbon (PfAC, containing ∼ 50% AC) to contaminated sediments from...