The role of adhesion in prey capture and predator defence in arthropods

Adhesive devices are used by arthropods not only in terrestrial locomotion but also in prey capture and predator defence. We argue that the physical mechanisms involved in both these contexts must mainly be capillarity and the viscosity of an adhesive secretion, whereas other mechanisms, such as friction or intermolecular forces, are of minor importance. Adhesive prey-capture devices might function as passive devices or might be actively extended toward the prey, sometimes in a very rapid manner. Adhesive mechanisms used for predator defence might involve firm adhesion to the substratum or the discharge of a sticky secretion to immobilize the appendages of the opponent. We review the occurrence of adhesive devices as employed in both functional contexts across the Arthropoda and argue that these mechanisms are of particular importance for slow-moving and relatively clumsy life forms. We discuss three case studies in more detail. (1) Loricera larvae (Carabidae) use galeae with an extremely flexible cuticle in combination with an adhesive secretion. (2) Adult Stenus species (Staphylinidae) employ two highly flexible paraglossae that are covered by an adhesive emulsion of lipid droplets dispersed in an aqueous proteinaceous liquid. (3) Springtails often adhere to the mouthparts, the antennae, the legs, or other parts of the integument of Stenus larvae before being captured with the mandibles.     

Use of isolated brain capillaries and cultured endothelial cells to study the blood-brain barrier

Brain capillary endothelial cells are responsible for forming the blood-brain barrier (BBB). Methods are now available to isolate microvessels from brain and study their biochemical and transport characteristics. From these investigations, new ideas have been proposed concerning the role of endothelial cells in the function of the BBB. More recently, success in culturing endothelial cells from brain microvessels has opened the way for novel approaches to the study of the regulation of endothelial cell permeability. We anticipate continued rapid progress in this area and expect that this will lead to a better understanding of the mechanisms involved in the regulation of BBB permeability and brain capillary function.     

Leprosy in armadillos (Dasypus novemcinctus) from Texas

Tissue sections from 237 nine-banded armadillos (Dasypus novemcinctus) from 51 central Texas counties were examined microscopically for acid-fast bacilli and/or lesions of leprosy. Neither were found. A review of the literature relative to the incidence of leprosy from armadillos in Texas indicates that residents of counties along the Texas Gulf Coast may be at risk of contracting leprosy by handling infected armadillos or their tissues.     

A simulation study of oscillating glycolysis: a comparison between a model and experiments

Glycolysis is the best known biochemical oscillator and suitable for the exploration of the basic features of biological rhythms on a biochemical and mathematical level. Because of our detailed knowledge of its component structure (enzyme kinetics, metabolite pattern) glycolysis can be described by a set of coupled nonlinear differential equations of first order with respect to time, whose individual terms consist of enzyme velocities assuming a steady state hypothesis for the enzymatic forms. Due to the feedback control of PFK by the adenylates the system is able to oscillate. The outcomes of a simplified model, containing only the basic elements of glycolysis, show good agreements with experimental results.