Pesticides are among the most pervasive environmental contaminants and they are an important potential risk for human health. Agricultural workers are constantly exposed to pesticide spray, drift and residues in the soil and foliage. Many agricultural pesticides are readily absorbed by the body, through contact with the skin, the respiratory...
Persistent organochlorines (OCs) bioaccumulate in aquatic biota and potentially impair reproduction via endocrine disruption. The present research evaluated estrogenic effects of the OCs, chlordecone (CD) and o,p'-DDT/DDE, and the antiestrogenicity of 3,4,5,3',4',5'-hexachlorobiphenyl (345-HCB) in juvenile rainbow trout, utilizing vitellogenesis as a biomarker. Vitellogenesis, estrogen regulated hepatic production of the yolk...
The environmental health science community recognizes polycyclic aromatic hydrocarbons (PAHs) as a re-emerging class of environmental pollutants due to their persistence and prominence in mixtures of concern. Due to their widespread distribution in the environment, exposure to PAHs often occur as complex chemical mixtures. Exposures are linked to numerous adverse...
Determination of the source and fate of natural (higher plant lipids, marine
lipids, etc.) and anthropogenically (e.g., petroleum, coal emissions) derived
hydrocarbons and oxygenated compounds in the environment was accomplished
using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS)
to characterize or identify molecular biomarkers to be utilized as tracers....
Oxidative stress occurs when the balance between reactive oxygen species and antioxidant defense mechanisms in the body becomes tipped heavily in favor of the reactive oxygen species. Reactive oxygen species can be present in excess due to elevated O2 levels, radiation, infection, smoking, or even excessive exercise. It is also...
During the peripartum period (3 weeks before through 3 weeks after calving, a.k.a. “transition”), high producing dairy cows experience, among others, , oxidative stress and immune suppression that compromise performance and increased incidence of diseases.Among trace minerals, supplementation of Selenium (Se) can help to improve the transition by enhancing glutathione...
Sources of polar/water-soluble organic compounds conjunctly with apolar biomarkers were characterized in natural organic matter. This multi-biomarker approach was accomplished by a simple analytical method consisting of extraction with dichloromethane:methanol (2:1, v/v), silylation and analysis by gaschromatography- mass spectrometry (GC-MS). Polar and apolar biomarkers, derived mainly from higher plants and...
Chlorophyllin (CHL), a water-soluble derivative of the green plant pigment, chlorophyll, is an effective antimutagen and anticarcinogen in various model systems when used as a modulator against a class of carcinogens that, in general, have a structure consisting of at least three fused rings. Dibenzo[a,l]pyrene (DBP), an extremely potent environmental...
A systematic study of highly branched isoprenoids (HBI) was carried out in
suspended particulate material (SPM) and Washington coastal sediments to determine
their origin and fate. SPM collected at 10 m depth was filtered through Nitex
membranes. C₂₅ HBI were found only in the 1.2-40 μm range over the shelf....
Changes in lifestyle over the last century have resulted in a dramatic increase in the incidence of diabetes in the United States (U.S.). Mexican-Americans, the largest Hispanic/Latino subgroup in the U.S., are 1.7x’s as likely to have diabetes as non- Hispanic Whites. Culturally appropriate approaches for treating diabetes in minority...
Reported here is an investigation to determine if azinphos-methyl (AZM), an
organophosphate insecticide, adducts to hemoglobin, and if so, whether the
hemoglobin adduct could be used as a quantitative marker of occupational AZM
exposure. We hypothesized that AZM, or a metabolite of AZM, binds to hemoglobin
in erythrocytes forming an...
All animals have developed the critical ability to detect, respond to, and detoxify a large array of environmental chemicals and stressors that can cause adverse health effects. Important examples of landmark contaminants around the world are polycyclic aromatic hydrocarbons (PAHs) and dioxins, both of which can act via the aryl...
This dissertation focuses on the application of diatom frustules, the biosilica shell of an algae possessing physical and photonic properties capable of enhancing optical signals, for the enhancement of optical sensing. In this work, we incorporate diatom frustules into biosensors for signal enhancement and improved target molecule detection. The potential...
Batch cultures of Candidatus Pelagibacter ubique were grown under iron-, organosulfur-, and nitrogen-limiting conditions to understand how this ubiquitous marine bacterium responds to and interacts with environments where growth is limited by the availability of these nutrients. Global gene expression was monitored using microarrays and quantitative mass spectrometry to observe...
As electronics reach nanometer size scales, new avenues of integrating biology and electronics become available. For example, nanoscale field-effect transistors have been integrated with single neurons to detect neural activity. Researchers have also used nanoscale materials to build electronic ears and noses. Another exciting development is the use of nanoscale...
The first part of the dissertation is to evaluate the use of proposed and established equations for area under the plasma concentration versus time (AUC) for molecules undergoing nonlinear Michaelis–Menten pharmacokinetic elimination. The effects of varying Michaelis-Menten parameters, rate of drug absorption, or bioavailability on the predictability of drug exposure...
During the past 30 years, numerous studies have focused on the toxicities of polycyclic aromatic hydrocarbons (PAH). Laboratory and field studies have helped elucidate the detrimental effects of these chemicals on growth, reproduction and immune response. Polycyclic aromatic hydrocarbons are in the priority list of chemicals to be studied by...
The consumption of cruciferous vegetables is associated with several health benefits, including cancer prevention. Many of these benefits are attributed to the phytochemical, sulforaphane (SFN), which is derived from cruciferous vegetables such as broccoli and broccoli sprouts. These vegetables contain glucoraphanin (GFN), SFN’s precursor, which is converted to SFN by...
Phytochemicals from cruciferous vegetables, such as broccoli, contain a multitude of bioactive compounds that prevent and suppress cancer and promote optimal health. Some of the health promoting effects of cruciferous vegetables are attributed to a class of compounds known as isothiocyanates (ITCs), a potent nuclear factor erythroid 2–related factor 2...
Pollutant body burdens, ability to tolerate supplementary stressors, and biomarkers of physiological stress were investigated in the ground beetle, Pterostichus oblongopunctatus (Coleoptera: Carabidae), inhabiting a gradient of heavy metal contamination in Poland. The central question was to determine if beetles inhabiting polluted habitats incurred costs compared with beetles in less...
Legumes are defined as the immature, germinated, or mature edible seeds of legume plants (Fabaceae). The primarily consumed legumes are dry beans, dry peas, lentils, chickpeas, cowpeas, fava beans, and pigeon peas, which are grouped as mature legumes, green beans and peas, which are considered green legumes, and sprouted or...
Two indigenous species of burrowing shrimp inhabit and often dominate the intertidal zone of estuaries along the US West Coast, the ghost shrimp, Neotrypaea californiensis, and the blue mud shrimp, Upogebia pugettensis. Both species are considered ecosystem engineers and play a role in maintaining estuarine health and ecosystem function. They...
Forest harvest can have significant impacts on forest ecosystems that may influence the capacity of soils to sequester carbon (C). The microbial community controls decomposition, which is a critical process in partitioning litter- and root-C between CO₂ and storage in semi-permanent soil-C pools. The objectives of this study were to...
Coral reefs, found in tropical regions, are renowned for their rich biodiversity and their contributions to ecological, cultural, and economic aspects worldwide. The success of coral reefs hinges on the symbiotic partnership between corals and their dinoflagellate algae, from the family Symbiodiniaceae. The algae reside within the coral host’s gastrodermal...
Remote health monitoring tools have significant potential to revolutionize the current healthcare paradigm. Such tools could improve efficiencies in healthcare by alerting patients and doctors to abnormal health conditions in real time, shortening the time to diagnose and treat ailments. To meet these needs, we pursue the development of fabric-based...
The DNA mismatch repair (MMR) pathway maintains genomic stability and
reduces cancer risk (colorectal and other internal cancers) by correcting polymerase
errors and activating cell cycle checkpoints and apoptosis in response to DNA damage.
Few studies have examined the influence of commonly encountered environmental
mutagens/carcinogens on the etiology of MMR-deficient...
The recent advent of large-scale microbiome studies enabled by high-throughput sequencing calls for innovative statistical methodologies that are capable of tackling a myriad of challenges presented by microbiome data. Compelled by this need, we focus on the development of statistical tools for two types of problems that arise in microbiome...
The field of toxicology is challenged with a vast number of environmental chemicals and mixtures to which humans and ecosystems are exposed with limited toxicity data available. Chemical hazard assessment traditionally utilizes mammalian models and can be both cost- and time-limiting and may pose ethical concerns. To rapidly tackle this...
There has been a tremendous growth in interest in carbon nanodots (C-dots) in the past several years. As a nascent nanomaterial, C-dots have shown great promise in applications that benefit from their superior water dispersibility, low toxicity, non-blinking fluorescent output, chemical and biological compatibility, ease of functionalization and resistance to...
Metabolomics and lipidomics lay the foundation of personalized medicine. The technological advancements in mass spectrometry techniques in combination with computational algorithms and methods have enabled the study of small molecules (metabolites and lipids) for understanding the disease state and biological pathways, the identification of biomarkers and the generation of predictive...
The human health effects of exposure to numerous single environmental contaminants have been well characterized. Yet, biomonitoring studies have detected multiple environmental chemicals in humans, highlighting the need to investigate the health effects of exposure to multiple environmental chemicals. Environmental data is highly complex, therefore current methods of defining environmental...
Polycyclic aromatic hydrocarbons (PAHs) are complex mixtures that form when organic matter is burned. Humans are primarily exposed to PAHs via air pollution from incomplete combustion of fossil fuels and biomass, such a motor vehicle exhaust, cigarette smoke, wood smoke, or industrial emissions; or via ingestion of PAHs bound to...
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment as components of fossil fuels and by-products of combustion. Defining toxicity mechanisms for this large family of multi-ring structures and substituted derivatives is a substantial challenge. Several PAHs, such as benzo(a)pyrene (BaP), are mutagenic, toxic to wildlife, and classified as probable...
There are more than 87,000 chemicals in current use with little to no toxicity information available. Assessing such a large number of chemicals using traditional methods would take an unreasonable amount of time and money, and require the use a large number of animals. The incorporation of high-throughput in vivo...
One post-transcriptional mechanism that regulates the progression of cancer and other diseases involves small 22-23 nucleotide sequences called microRNA (miR). Early detection of small changes in concentration of these biomarkers holds potential to diagnose diseases at their earliest stages. Use of current nucleic-acid based biosensors, like molecular beacons, for in...
Fluorescence has proven to be a robust and powerful method of analysis in numerous fields: forensics, pharmaceutics, geology, food science, and environmental sciences have all developed a large collection of fluorescence instruments and methods to overcome application-specific challenges. Biological applications saw the same development of a fluorescence toolkit with methods...
Environmental toxicologists and public health officials are responsible for assisting in the identification, management, and mitigation of public health hazards. As a result, there is a continued need for robust analytical tools that can aid in the rapid quantification and characterization of chemical exposure. In the first research phase, we...
Oxidative stress is recognized as an important underlying factor in the
pathogenesis of many degenerative diseases as well as normal senescence. The
free radicals, reactive oxygen species (ROS) and electrophiles produced during
oxidative stress are capable of modifying nucleic acids, lipids and proteins. There
are a variety of oxidative modifications...
Metabolomics has recently gained momentum in biomolecule research and complements the genomics and proteomics research space. Metabolomics strives to detect, identify, and quantify all metabolites present in biological samples. In particular, biomolecular analysis using ultra-performance liquid chromatography combined with mass spectrometry (UPLC-MS) has become increasingly important for metabolomic analyses. Similarly,...
Analytical techniques are utilized in a wide variety of applications. Traditionally, analytical measurements are achieved by trained personnel in a laboratory setting using expensive scientific instruments, which limits their applicability in resource-limited areas and point-of-care applications. Therefore, the concept of enabling these laboratory-based qualitative and quantitative assays in microfluidic device...
Small mountainous watersheds are disproportionate sources of land-derived particulate organic matter (POM) to long-term sinks like lake bottoms and the ocean. As such, these ecosystems are an essential component of the global carbon cycle. The burial of POM in lacustrine and marine sediments contributes to the drawdown of atmospheric CO2...
The buildup of reactive oxygen species (ROS) and reactive nitrogen and oxygen species (RNS) is known as oxidative stress. Oxidative stress results in a wide variety of modification to biological macromolecules including nucleic acids, lipids, and proteins. For at least 30 years it has been known that high levels of...
The general theme of this dissertation is the development of new analytical sensors to quantitatively study biological and environmental samples in aqueous and non-aqueous environments. A platinum ultramicroelectrode (UME) and a unique carbon-based pH microprobe were used to design a new SECM-based electrochemical bioassay. The Pt UME was used to...
Alcohol is a widely consumed, nonessential, bioactive nutrient with end-organ effects on the skeleton. Moderate levels of alcohol consumption are generally associated with increased bone mineral density (BMD), whereas higher intake levels result in reduced bone formation, bone loss, and increased risk for osteoporotic fracture. Given the negative impact of...
Wastewater epidemiology is an emerging discipline that requires collaborative research involving analytical chemists, drug epidemiologists, and wastewater engineers. Wastewater epidemiology involves the sampling and quantitative analysis of raw wastewaters from communities for illicit drugs and their metabolites. Mass loads (mass per day) and per capita (mg per day per person)...
Oxidative stress is defined as an imbalance that favors the production of reactive oxygen species (ROS) over an organism's antioxidant defense. ROS have the ability to damage, either directly or indirectly, biomolecules including DNA, proteins, carbohydrates, and lipids. Various pathological conditions and environmental and chronic diseases have been associated with...
There is a strong evidence that human papillomavirus (HPV) is the key causative agent of cervical cancer. However, the majority of women who are exposed to the oncogenic HPV do not develop invasive cervical cancer, suggesting that other factors could play a role in the cause and progression of cervical...
The early marine phase following freshwater emigration has been identified as a critical period in salmonid (Oncorhynchus spp.) life history, characterized by high but variable mortality. Consistent with the “growth-mortality” and “bigger-is-better” hypotheses, at least some of the mortality during the critical period appears to be size-dependent – with smaller...
Exposure assessment is necessary to determine the frequency and magnitude of environmental contaminants, especially since exposure may lead to adverse health outcomes. Traditional personal exposure assessment tools such as biological samples are limited in their ability to capture a wide range of chemical exposures from a single sample, and others...
