In vitro modulation of oral bacterial adhesion to saliva-coated hydroxyapatite beads by milk casein derivatives

Bovine caseinate, derivatives of its glycosylated moiety [caseinoglycomacropeptide (CGP)], and caseinophosphopeptides were evaluated as inhibitors of adhesion of oral bacteria to saliva‐coated hydroxyapatite beads (S‐HA). All milk casein‐derived components behaved as potent inhibitors of Streptococcus sanguis OMZ 9 and Streptococcus sobrinus OMZ 176 adhesion to S‐HA, whereas neither bovine serum albumin nor polyethyleneglycol were able to interfere with the adhesion of these strains. By contrast, none of the molecular species tested was able to inhibit the attachment of Actinomyces viscosus Ny 1 to S‐HA. On the other hand, casein derivatives were shown to displace human serum albumin from S‐HA beads. They were also able to bind to the bacterial cell surface of all strains examined. Collectively, these findings suggest that interactions between acidic casein‐derived milk components and the biological surfaces involved in bacterial adhesion to S‐HA result in an inhibitory effect that is selective for the oral streptococci examined. </p

Globalization and cognitive enhancement: emerging social and ethical challenges for ADHD clinicians

Globalization of ADHD and the rise of cognitive enhancement have raised fresh concerns about the validity of ADHD diagnosis and the ethics of stimulant drug treatment. We review the literature on these two emerging phenomena, with a focus on the corresponding social, scientific and ethical debates over the universality of ADHD and the use of stimulant drug treatments in a global population of children and adolescents. Drawing on this literature, we reflect on the importance of ethically informed, ecologically sensitive clinical practices in relation to ADHD diagnosis and treatment

Uptake of ammonium and soluble reactive phosphorus in forested streams: influence of dissolved organic matter composition

Many microbes responsible for inorganic nutrient uptake and transformation utilize dissolved organic matter (DOM) as a nutrient or energy source, but little is known about whether DOM composition is an important driver of nutrient uptake in streams. Our goal was to determine whether incorporating DOM composition metrics with other more commonly considered biological, physical, and chemical variables improved our ability to explain patterns of ammonium ( NH+4 –N) and soluble reactive phosphorus (SRP) uptake across 11 Lake Superior tributaries. Nutrient uptake velocities (Vf) ranged from undetectable to 14.6 mm min−1 for NH+4 –N and undetectable to 7.2 mm min−1 for SRP. Logistic regressions suggested that DOM composition was a useful predictor of where SRP uptake occurred (4/11 sites) and NH+4 –N concentration was a useful predictor of where NH+4 –N uptake occurred (9/11 sites). Multiple regression analysis revealed that the best models included temperature, specific discharge, and canopy cover, and DOM composition as significant predictors of NH+4 –N Vf. Partial least squares revealed fluorescence index (describing the source of aquatic fulvic acids), specific ultraviolet absorbance at 254 nm (an indicator of DOM aromaticity), temperature, and conductivity were highly influential predictors of NH+4 –N Vf. Therefore, streams with higher temperatures, lower solute concentrations, more terrestrial DOM signal and greater aromaticity had greater NH+4NH4+ –N Vf. Our results suggest that DOM composition may be an important, yet often overlooked, predictor of NH+4 –N and SRP uptake in deciduous forest streams that should be considered along with commonly measured predictors