Biochemistry Commons^™

High Throughput Analysis To Study Emerging Pollutants And Nanoparticle Fate In Biological Systems, Xiaolong He

Doctoral Dissertations

”The increasing applications of emerging and fugitive contaminants (EFCs) and engineered nanoparticles (ENPs) attract significant research interest for their potential risks to human health and the environment. In order to assess the health risks of these emerging contaminants, rapid and reliable analytical methods to measure the concentrations and fates of these contaminants are imperative. This dissertation focuses on the developments of advanced analytical methods and their applications to study those emerging contaminants in crop plant and simulated gastric fluid (SGF). Three types of mass spectrometry based methodologies have been developed, one is freeze-thaw/centrifugation extraction followed by high performance liquid chromatography …

Environmental Risk Factors For Inflammatory Bowel Disease: Triclosan And Other Consumer Antimicrobials, Katherine Z. Sanidad

Doctoral Dissertations

Inflammatory bowel disease (IBD) has become a serious health problem since the incidence and prevalence of IBD has dramatically increased throughout the world. There is evidence that environmental factors are primarily responsible for the increase of IBD, therefore, it is important to identify novel environmental risk factors to reduce the risk of IBD and its associated diseases. Antimicrobials used in consumer products might serve as environmental risk factors for IBD and its associated diseases. Triclosan (TCS), triclocarban (TCC), benzalkonium chloride (BAC), benzethonium chloride (BET), and chloroxylenol (PCMX) are widely used antimicrobial ingredients in consumer products and are ubiquitous contaminants in …

Hybridized Polymeric Nano-Assemblies: Key Insights Into Addressing Mdr Infections, Ryan Landis

Doctoral Dissertations

Multidrug-resistant (MDR) bacteria contribute to more than 700,000 annual deaths world-wide. Millions more suffer from limb amputations or face high healthcare treatment costs where prolonged and costly therapeutic regimens are used to counter MDR infections. While there is an international push to develop novel and more powerful antimicrobials to address the impending threat, one particularly interesting approach that has re-emerged are essential oils, phytochemical extracts derived from plant sources. While their antimicrobial activity demonstrates a promising avenue, their stability in aqueous media, limits their practical use in or on mammals. Inspired by the versatility of polymer nanotechnology and the sustainability …

Imidacloprid, A Neonicotinoid Insecticide, Impairs Lipid And Glucose Metabolism, Quancai Sun

Doctoral Dissertations

Emerging evidence suggests that environmental pollutants, including insecticides, are linked to excessive weight gain and altered glucose homeostasis. However, there is currently limited knowledge regarding the biochemical mechanisms by which exposure to insecticides contribute to obesity and its associated pathologies. We first studied the influence of fipronil (a phenylpyrazole family insecticide) on 3T3-L1 adipogenesis. Recently imidacloprid, a neonicotinoid insecticide, was reported to potentiate adipogenesis and insulin resistance in vitro. The current studies also determined the effects of imidacloprid exposure and its interaction with dietary fat in the development of adiposity and insulin resistance using both male and female C57BL/6J …

Adsorption Of Biomolecules On Carbon-Based Nanomaterial As Affected By Surface Chemistry And Ionic Strength, Peng Du

Doctoral Dissertations

In the first project, we examined adsorption of bovine serum albumin (BSA) and lysozyme (LYZ) on carboxylated (CM), hydroxylated (HM) and graphitized (GM) multi-wall carbon nanotubes (CNTs). All adsorption isotherms were fitted well with Langmuir model. Maximum adsorption capacities (mg/g) followed: HM>CM>GM for both BSA and LYZ, which positively related to the surface areas of the three CNTs. However, after surface area normalization, adsorption capacity (mg/m²) followed: HM>GM>CM for BSA and GM>CM>HM for LYZ, indicating that functional groups and hydrophobicity of CNTs also contributed to protein adsorption. In addition, adsorption of LYZ …

Ligand-Receptor Interactions For Supramolecular Disassembly With Applications In Screening And Drug Delivery, Diego Amado Torres

Doctoral Dissertations

Proteins have the capacity to bind specific sets of compounds known as ligands, these are small molecules with a recurrent theme in their molecular design that is a characteristic exploited here to (i) identify particular affinities of small molecules for proteins with the aim of using them as ligands, inhibitors, or targeting moieties in more complex systems by means of a methodology that screens small molecules based on protein affinity; (ii) decorate a self-assembling supramolecular system at different positions, making it responsive to a complementary protein with the aim of exploring differences in disassembly and sensitivity of the release of …

Applications And Improvements In The Molecular Modeling Of Protein And Ligand Interactions, Jason Bret Harris

Doctoral Dissertations

Understanding protein and ligand interactions is fundamental to treat disease and avoid toxicity in biological organisms. Molecular modeling is a helpful but imperfect tool used in computer-aided toxicology and drug discovery. In this work, molecular docking and structural informatics have been integrated with other modeling methods and physical experiments to better understand and improve predictions for protein and ligand interactions. Results presented as part of this research include:

1.) an application of single-protein docking for an intermediate state structure, specifically, modeling an intermediate state structure of alpha-1-antitrypsin and using the resulting model to virtually screen for chemical inhibitors that can …

Layer-By-Layer Self -Assembly For Enzyme And Dna Encapsulation And Delivery, Amish Patel

Doctoral Dissertations

Thin wall microcapsules were formed via Layer-by-Layer Self-Assembly of alternate adsorption of oppositely charged polyelectrolyte on microcores. After the core dissolution, empty polymeric shells with 20–25 nm thick walls were obtained. These microcapsules were loaded with Myoglobin, Hemoglobin and Glucose Oxidase by opening capsule pores at low pH and closing them at higher pH. The native structure of the enzyme was not affected due to different treatments. Biocompatible nanoshells were also prepared for encasing DNA. Using the same Layer-by-Layer Self-Assembly approach nanoparticle were constructed containing DNA as one of the layers. The nanoparticles of different architecture were used to deliver …