Changes in spontaneous spike activities recorded from murine frontal cortex networks grown on substrate-integrated microelectrodes were used to determine the dissociation constant (KB) of three GABAA antagonists. Neuronal networks were treated with fixed concentrations of GABAA antagonists and titrated with muscimol, a GABAA receptor agonist. Muscimol decreased spike activity in a concentration dependent manner with full efficacy (100% spike inhibition) and a 50% inhibitory concentration (IC50) of 0.14 ± 0.05 µM (mean ± SD, n=6). At 10, 20, 40 and 80 µM bicuculline, the muscimol IC50 values were shifted to 4.3 ± 1.8 µM (n=6), 6.8 ± 1.7 µM (n=6), 19.3 ± 3.54 µM (n=10) and 43.5 µM (n=2), respectively (mean ± SD). Muscimol titration in the presence of 10, 20, 40 µM of gabazine resulted in IC50s values of 20.1 (n=2), 37.17 (n=4), and 120.45 (n=2), respectively. In the presence of 20, 80, and 160 µM of TMPP (trimethylolpropane phosphate) the IC50s were 0.86 (n=2), 3.07 (n=3), 6.67 (n=2) µM, respectively. Increasing concentrations of GABAA antagonists shifted agonist log concentration-response curves to the right with identical efficacies, indicating direct competition for the GABAA receptor. A Schild plot analysis with linear regression resulted in slopes of 1.18 ± 0.18, 1.29 …

A study of the life history and ecology of Camelobaetidius variabilis was conducted in Honey Creek, OK from February 2003-April 2004. Nymph development was assessed using changes in external morphology. Laboratory reared nymphs were used to calculate number of degree days to complete development (772 degree days at 20.8° C ±.38° C), which was used to determine voltinism. Field collected nymph microhabitat distribution was used in assessing microhabitat distribution. Nymphal thermoregulation was assessed during the winter and spring by comparing nymphal numbers present in shaded and un-shaded habitats. Camelobaetidius variabilis nymphs showed preference for algal microhabitats during the spring and leaf packs in the winter. Nymphs inhabited leaf packs to increase metabolic rate during the winter. Increased temperatures aid in development of nymphs. Camelobaetidius variabilis exhibited a multivoltine life cycle with six overlapping generations.

Pseudomonas aeruginosa is a Gram-negative rod, aerobic, non-fermenting, oxidase positive, pigment producing, and nutritionally versatile bacterium. Infections by P. aeruginosa are the most important cause of morbidity and mortality in immunocompromised patients, given virulence factor production that suppresses antibiotic therapy and promotes persistent infection. This research is the first comprehensive report of the pyrimidine biosynthetic pathway for all phases of growth in minimal and rich media coupled with the evaluation of virulence factor production of P. aeruginosa in comparison to four other bacterial species (Pseudomonas putida, Pseudomonas fluorescens, Burkholderia cepacia, and Escherichia coli wild-type strains). Cellular growth and passing genetic information to the next generation depend on the synthesis of purines and pyrimidines, the precursors of DNA and RNA. The pyrimidine biosynthetic pathway is essential and found in most organisms, with the exception of a few parasites that depend upon the pyrimidine salvage pathway for growth. Both the pyrimidine biosynthetic and salvage enzymes are targets for chemotherapeutic agents. In our laboratory, research on pyrimidine auxotrophic mutants showed the role of the pyrimidine biosynthetic pathway and its intermediates on P. aeruginosa metabolism and impaired virulence factors production. The present research shows that pyrimidine enzymes are active in all phases of growth, …