Is sugar as sweet to the palate as seeds are appetizing to the belly? Taste responsiveness to five food-associated carbohydrates in zoo-housed white-faced sakis, Pithecia pithecia.

Differences in taste perception between species are thought to reflect evolutionary adaptations to dietary specialization. White-faced sakis (Pithecia pithecia) are commonly considered as frugivores but are unusual among primates as they do not serve as seed dispersers but rather prey upon the seeds of the fruits they consume and are thought to exploit the lipids and proteins that these seeds contain in high amounts. Using a two-bottle preference test of short duration we therefore assessed whether this dietary specialization affects the taste responsiveness of four adult white-faced sakis for five food-associated carbohydrates. We found that the sakis significantly preferred concentrations as low as 10 mM sucrose, 10-40 mM fructose, 20-30 mM glucose and maltose, and 30-40 mM lactose over tap water. When given the choice between all binary combinations of these five saccharides presented at equimolar concentrations of 100, 200, and 300 mM, respectively, the sakis displayed significant preferences for individual saccharides in the following order: sucrose > fructose > glucose ≥ maltose = lactose. These results demonstrate that seed-predating white-faced sakis have a well-developed taste sensitivity for food-associated carbohydrates which is not inferior to that of most other primates including seed-dispersing frugivores, but rather ranks among the more sweet-taste sensitive species. Further, they show that their pattern of relative preference for the five carbohydrates is similar to that found in other frugivorous primate species. These findings may represent an example of Liem's paradox as the sakis' morphological adaptations to efficiently predate on and exploit the lipid- and protein-rich hard-shelled seeds of fruits does not compromise their ability to detect the carbohydrates found in the pulp of fruits at low concentrations.

Toxicity testing is evolving!

The efficient management of the continuously increasing number of chemical substances used in today's society is assuming greater importance than ever before. Toxicity testing plays a key role in the regulatory decisions of agencies and governments that aim to protect the public and the environment from the potentially harmful or adverse effects of these multitudinous chemicals. Therefore, there is a critical need for reliable toxicity-testing methods to identify, assess and interpret the hazardous properties of any substance. Traditionally, toxicity-testing approaches have been based on studies in experimental animals. However, in the last 20 years, there has been increasing concern regarding the sustainability of these methodologies. This has created a real need for the development of new approach methodologies (NAMs) that satisfy the regulatory requirements and are acceptable and affordable to society. Numerous initiatives have been launched worldwide in attempts to address this critical need. However, although the science to support this is now available, the legislation and the pace of NAMs acceptance is lagging behind. This review will consider some of the various initiatives in Europe to identify NAMs to replace or refine the current toxicity-testing methods for pharmaceuticals. This paper also presents a novel systematic approach to support the desired toxicity-testing methodologies that the 21st century deserves.

Sulfur Hexafluoride and Potassium Bromide as Groundwater Tracers for Managed Aquifer Recharge.

Sulfur hexafluoride (SF6 ) is an established tracer for use in managed aquifer recharge projects. SF6 exsolves from groundwater when it encounters trapped air according to Henry's law. This results in its retardation relative to groundwater flow, which can help determine porous media saturation and flow dynamics. SF6 and the conservative, nonpartitioning tracer, bromide (Br- added as KBr), were introduced to recharge water infiltrated into stacked glacial aquifers in Thurston County, Washington, providing the opportunity to observe SF6 partitioning. Br- , which is assumed to travel at the same velocity as the groundwater, precedes SF6 at most monitoring wells (MWs). Average groundwater velocity in the unconfined aquifer in the study area ranges from 3.9 to 40 m/d, except in the southwestern corner where it is slower. SF6 in the shallow aquifer exhibits an average retardation factor of 2.5 ± 3.8, suggesting an air-to-water ratio on the order of 10-3 to 10-2 in the pore space. Notable differences in tracer arrival times at adjacent wells indicate very heterogeneous conductivity. One MW exhibits double peaks in concentrations of both tracers with different degrees of retardation for the first and second peaks. This suggests multiple flowpaths to the well with variable saturation. The confining layer between the upper two aquifers appears to allow intermittent connection between aquifers but serves as an aquitard in most areas. This study demonstrates the utility of SF6 partitioning for evaluating hydrologic conditions at prospective recharge sites.