V-ATPases are complex proteins consisting of a peripheral, ATP-hydrolysing V(1) complex and a membrane-bound H(+)-translocating V(o) complex. The plasma membrane V-ATPase from the tobacco hornworm (Manduca sexta) midgut is made up of eight different V(1) and four different V(o) subunits. During starvation and moulting, V-ATPase activity decreases as a result of the dissociation of the V(1) comp...

Stressful disturbances activate the hypothalamic-pituitary-adrenal (HPA) axis and result in the release of glucocorticoid (GC) hormones. This characteristic stress response supports immediate energetic demands and subsequent recovery from disturbance. Increased baseline GC concentrations may indicate chronic stress and can impair HPA axis function during exposure to additional stressors. Levels...

Phocid seals go through dramatic seasonal changes in body mass and composition as a result of the spatial and temporal separation of foraging, reproduction and moulting. These changes in body fat content and body mass result in seasonal changes in buoyancy, which in turn may influence diving behaviour. We examined the longitudinal changes in buoyancy and diving behaviour of 14 adult grey seals ...

BACKGROUND The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent ...

The venom of the ectoparasitoid Eulophus pennicornis is known to induce developmental arrest in parasitized hosts through the prevention of moulting. However, little work has explored how the venom affects different host stages, whether the observed effects vary with different doses, and whether the venom has activity in non-host species. Injections of venom doses of 0.5 g protein prevented the...

Pharmaceuticals contribute greatly to human and animal health. Given their specific biological targets, pharmaceuticals pose a significant environmental risk by affecting organisms and ecosystem processes, including leaf-litter decomposition. Although litter decomposition is a central process in forest streams, the consequences of exposure to pharmaceuticals remain poorly known. The present stu...