Cell surface and exopolymer characterization of laboratory stabilized activated sludge from a beverage bottling plant.

Fermentor-stabilized activated sludge from an industrial beverage bottling plant was grown on three different food sources: normal plant wastewater, plant wastewater containing high sucrose concentrations, and a synthetic glucose-based feed stock. Surface charge, hydrophobicity, and exopolysaccharide composition were measured on the stabilized bacterial flocs. Cell surface charge was measured by electrophoretic mobility, dye exchange titration, and a standard colloid titration, while cell hydrophobicity was determined using the bacterial adhesion to hydrocarbons (BATH) test. Exopolysaccharide profiles were determined by measuring concentrations of glucose, galactose, mannose, glucuronic, and galacturonic acids in digested exopolymer extractions using HPLC. Changes in the physical surface properties of the bacteria and the chemical composition of the extracted exopolymers were correlated with differences in the three food sources. Cell surface hydrophobicity was similar for cultures grown on different plant wastewaters, while the culture grown on synthetic food produced less floc hydrophobicity. Electrophoretic mobility measurements, charge titrations, and dye exchange titrations showed different total surface charge as well as varying charge availability. Additionally, total surface charge and total exopolysaccharide concentrations appeared less dependent on food source than the food-to-mass ratio. High concentrations of biodegradable food produced dispersed growth and high concentrations of exopolysaccharides that contributed to poor settling.

Distribution of functional adrenergic receptor subtypes in the microcirculation of rat trachea.

Although blood flow to the pulmonary airways is known to be largely under sympathetic control, virtually nothing is known about adrenergic regulation of vascular segments within the airway microcirculation. To evaluate the distribution of functional adrenergic receptor subtypes in the microvessels of the large airways, the change in diameter of adventitial vessels in rat trachea was measured following suffusion with selective and nonselective receptor agonists and antagonists. Microvessels were viewed with a video microscope, and vessel diameters were measured using video calipers. Arterioles (11.0 to 40.0 microns, n = 32), small postcapillary venules (11.0 to 26.0 microns, n = 16), medium venules (28.0 to 59.5 microns, n = 40), and large collecting venules (61.0 to 99.0 microns, n = 42) were distinguished. Similar sensitivities to norepinephrine (NE), a mixed alpha 1 and alpha 2 agonist, were observed in arterioles and medium venules with EC50 (agonist concentration needed to produce 50% of the maximal response) for contraction of 2.4 x 10(-7) and 3.3 x 10(-7) M, respectively. Large venules (EC50 of 1.6 x 10(-6) M) were significantly (p < 0.05) less sensitive than arterioles to NE. In the presence of propranolol, a beta receptor antagonist, the EC50 values for NE were not different between the three vessel groups, although the response to low doses of NE was significantly increased in arterioles. When vessels were treated with propranolol and phenylephrine, a selective alpha 1 agonist, arterioles (EC50 of 4.1 x 10(-7) M) were significantly more sensitive than large venules (EC50 of 4.9 x 10(-6) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Emotional correlates of fluency test and maze performance.

This study tested the hypothesis that depression, anxiety, and bizarre thought content, as measured by MMPI-2 scales, would show a negative relationship with performance on widely used measures of executive functioning. Subjects were 70 male psychiatric patients who were ostensibly free of any neurologic disease or history of substance abuse. Correlational analyses were performed between age and education-corrected scores on the Controlled Oral Word Association Test (FAS), Design Fluency, and WISC-R Mazes, and scores on MMPI-2 scales D, PT, Anxiety, Fears, Obsessional Thinking, Depression, and Bizarre Mentation. The findings suggest that fluency and maze performance is (1) largely independent of measures of depression (D, DEP) and bizarre mentation (BIZ); (2) mildly associated with a measure of generalized anxiety (ANX); and (3) strongly related to an MMPI-2 measure of fearfulness (FRS).