Characterization of Oligomer Formation of Surfactant Protein-D (SP-D) Using AF4-MALLS.

Background: Surfactant protein-S (SP-D) is a naturally occurring lung protein with the potential to treat pulmonary infections. A recombinant surfactant protein-D (SP-D) has been produced and was previously found to exist in multiple oligomeric states.

Introduction: Separation and characterization of interconverting oligomeric states of a protein can be difficult using chromatographic methods, so an alternative separation technique was employed for SPD to characterize the different association states that exist.

Analysis of Peptides using Asymmetrical Flow Field-flow Fractionation (AF4).

While asymmetrical flow field-flow fractionation (AF4) has been widely used for separation of high molecular weight species and even particles, its ability to resolve lower molecular weight species has rarely been explored. Over the course of many projects, we have discovered that AF4 can be an effective analytical method for separating peptides from oligomers and higher molecular weight aggregates. The methodology can be used even for peptides as small as 2 kD in molecular weight.

Denaturation and Aggregation of Interferon-τ in Aqueous Solution.

Purpose: To evaluate the different degrees of residual structure in the unfolded state of interferon-τ using chemical denaturation as a function of temperature by both urea and guanidinium hydrochloride.

Methods: Asymmetrical flow field-flow fractionation (AF4) using both UV and multi-angle laser light scattering (MALLS). Flow Microscopy.

Assessing the Fate of an Aromatic Hydrocarbon Fluid in Agricultural Spray Applications Using the Three-Stage ADVOCATE Model Framework.

Components of emulsifiable concentrates (ECs) used in pesticide formulations may be emitted to air following application in agricultural use and contribute to ozone formation. A key consideration is the fraction of the ECs that is volatilized. This study is designed to provide a mechanistic model framework for estimating emissions of an aromatic hydrocarbon fluid used in ECs based on the results of spray chamber experiments that simulate fate as the fluids become subject to volatilization, sorption to soil, and biodegradation.

Use of passive samplers for improving oil toxicity and spill effects assessment.

Methods that quantify dissolved hydrocarbons are needed to link oil exposures to toxicity. Solid phase microextraction (SPME) fibers can serve this purpose. If fibers are equilibrated with oiled water, dissolved hydrocarbons partition to and are concentrated on the fiber.

Evaluating toxicity of heavy fuel oil fractions using complementary modeling and biomimetic extraction methods.

The toxicity of chemically dispersed heavy fuel oil (HFO) and 3 distillate fractions to rainbow trout (Oncorhynchus mykiss) embryos was evaluated using the PETROTOX model and a biomimetic extraction technique that involved passive sampling of oil-contaminated test media with solid-phase microextraction (SPME) fibers. Test solutions for toxicity testing were generated using a combination of dispersant and high-energy mixing. The resulting water accommodated fractions (WAF) provided complex exposure regimens that included both dissolved hydrocarbons and oil droplets.