Reduced VIP Expression Affects Circadian Clock Function in VIP-IRES-CRE Mice (JAX 010908).

Circadian rhythms are programmed by the suprachiasmatic nucleus (SCN), which relies on neuropeptide signaling to maintain daily timekeeping. Vasoactive intestinal polypeptide (VIP) is critical for SCN function, but the precise role of VIP neurons in SCN circuits is not fully established. To interrogate their contribution to SCN circuits, VIP neurons can be manipulated specifically using the DNA-editing enzyme Cre recombinase.

Life stage and species identity affect whether habitat subsidies enhance or simply redistribute consumer biomass.

Quantifying the response of mobile consumers to changes in habitat availability is essential for determining the degree to which population-level productivity is habitat limited rather than regulated by other, potentially density-independent factors. Over landscape scales, this can be explored by monitoring changes in density and foraging as habitat availability varies. As habitat availability increases, densities may: (1) decrease (unit-area production decreases; weak habitat limitation); (2) remain stable (unit-area production remains stable; habitat limitation) or (3) increase (unit-area production increases; strong habitat limitation).

Threshold effects of habitat fragmentation on fish diversity at landscapes scales.

Habitat fragmentation involves habitat loss concomitant with changes in spatial configuration, confounding mechanistic drivers of biodiversity change associated with habitat disturbance. Studies attempting to isolate the effects of altered habitat configuration on associated communities have reported variable results. This variability may be explained in part by the fragmentation threshold hypothesis, which predicts that the effects of habitat configuration may only manifest at low levels of remnant habitat area.

Fiddler crabs facilitate Spartina alterniflora growth, mitigating periwinkle overgrazing of marsh habitat.

Ecologists have long been interested in identifying and testing factors that drive top-down or bottom-up regulation of communities. Most studies have focused on factors that directly exert top-down (e.g.

Chitosan coating improves retention and redispersibility of freeze-dried flavor oil emulsions.

Flavor oils are often encapsulated as emulsions by drying processes such as freeze-drying or spray-drying, using mainly macromolecular emulsifiers such as gums and proteins to stabilize the emulsions during drying. The objective of the present study was to examine whether a combination of a charged small-molecule emulsifier and an oppositely charged polysaccharide adsorbed to the emulsion droplet surface can substitute commonly used encapsulation materials for the drying of flavor oil emulsions. To this end, polysaccharide-coated flavor oil emulsions were prepared by high-pressure homogenization of mixtures consisting of a flavor oil (R-carvone), a negatively charged citric acid ester small-molecule emulsifier (citrem), and various concentrations of a positively charged polysaccharide (chitosan) in acetate buffer at pH 4.

Effects of farnesol on the physical properties of DMPC membranes.

Farnesol interacts with membranes in a wide variety of biological contexts, yet our understanding of how it affects lipid bilayers is not yet complete. This study investigates how the 15-carbon isoprenoid, farnesol, influences the phase behaviour, lateral organization, and mechanical stability of dimyristol phosphatidylcholine (DMPC) model membranes. Differential scanning calorimetry (DSC) of multilamellar DMPC-farnesol mixtures (up to 26 mol% farnesol) demonstrates how this isoprenoid lowers and broadens the gel-fluid phase transition.

Decoupled phase transitions and grain-boundary melting in supported phospholipid bilayers.

Two separate liquid-solid phase transitions are detected in the two monolayers of a mica-supported phospholipid bilayer by atomic force microscopy. The phase transitions of the two monolayers are decoupled by the stronger interaction between the lipid headgroups of the proximal monolayer and the mica support. The transition temperature of the proximal monolayer is increased and this transition occurs over a narrower temperature range.

NMR studies of the aggregation of glucagon-like peptide-1: formation of a symmetric helical dimer.

Nuclear magnetic resonance (NMR) spectroscopy reveals that higher-order aggregates of glucagon-like peptide-1-(7-36)-amide (GLP-1) in pure water at pH 2.5 are disrupted by 35% 2,2,2-trifluoroethanol (TFE), and form a stable and highly symmetric helical self-aggregate. NMR spectra show that the helical structure is identical to that formed by monomeric GLP-1 under the same experimental conditions [Chang et al.