Rodney D. Johnson

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Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to(More)
The fungal endophytes Neotyphodium lolii and Neotyphodium sp. Lp1 from perennial ryegrass (Lolium perenne), and related endophytes in other grasses, produce the ergopeptine toxin ergovaline, among other alkaloids, while also increasing plant fitness and resistance to biotic and abiotic stress. In the related fungus, Claviceps purpurea, the biosynthesis of(More)
Ketoconazole (KTC) is a model pharmaceutical representing imidazole and triazole pesticides, which inhibit fungal growth through blocking a cytochrome P450 (CYP)-mediated step in ergosterol biosynthesis. Several of these fungicides have been shown to be reversible inhibitors of CYPs in vertebrates (primarily mammals), including CYP isoforms involved in the(More)
Nineteen children who met criteria for attention deficit disorder (ADD) received neurodevelopmental attention testing and central auditory processing (CAP) tests. The CAP tests consisted of the Staggered Spondaic Word (SSW) test and the Willeford battery of tests. Teacher and parent questionnaires (originally devised at the Learning Disabilities Clinic, The(More)
Samples of sediment and biota were collected from sites in the lower Fox River and southern Green Bay to determine existing or potential impacts of sediment-associated contaminants on different ecosystem components of this Great Lakes area of concern. Evaluation of benthos revealed a relatively depauperate community, particularly at the lower Fox River(More)
Spironolactone is a pharmaceutical that in humans is used to treat conditions like hirsutism, various dermatologic afflictions, and female-pattern hair loss through antagonism of the androgen receptor. Although not routinely monitored in the environment, spironolactone has been detected downstream of a pharmaceutical manufacturer, indicating a potential for(More)
Trenbolone is an androgen agonist used in cattle production and has been measured in aquatic systems associated with concentrated animal-feeding operations. In this study, the authors characterized the effects of aqueous exposure to 17β-trenbolone during larval Xenopus tropicalis development. Trenbolone exposure resulted in increased mortality of(More)
A process based on reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed for the purification of biosynthetic human insulin (BHI). The RP-HPLC procedure has been successfully integrated into the multimodal chromatographic production process used to purify kilogram quantities of BHI. Axial compression column technology was used(More)