Adapting to changing poaching intensity of yellow-shouldered parrot (Amazona barbadensis) nestlings in Margarita Island, Venezuela

The yellow-shouldered parrot (Amazona barbadensis) is listed in Venezuela as Endangered and internationally as Vulnerable, primarily due to poaching for the illegal pet trade. Various interventions have been implemented to reduce poaching (increasing the population from 700 in 1989 to 1600 in 2009), but poaching pressure is still high, and is ever-changing, requiring an evolving response. Between 2000 and 2003, our only intervention was environmental education in schools: in the short term, unsurprisingly, it had no impact on poaching, which reached 100% of nestlings in monitored nests. From 2004 onwards, we implemented a set of new field interventions. In 2004, 24 h field surveillance decreased poaching to 56%. In 2005, the addition of foster nests and a pilot test of “assisted breeding” brought the figure down to 18%. In 2006, assisted breeding was expanded, achieving 0% poaching. In 2007, poachers raided our “secure” site, and took 34 nestlings, bringing poaching up to 60%. A pilot study of artificial nests offered promising results. In 2008 and 2009, the addition of patrolling by local police reduced poaching to 16% and 1%, respectively. During 2004–2009, nestling poaching averaged 25%. Ensuring parrot recruitment in the future will require a combination of the strategies employed to date; in the short term, expanding the use of artificial nests to increase availability of nesting sites in easily-patrolled areas has the most potential to build on past successes.     

Differential transmission of actin motion within focal adhesions

Cell migration requires the transmission of motion generated in the actin cytoskeleton to the extracellular environment through a complex assembly of proteins in focal adhesions. We developed correlational fluorescent speckle microscopy to measure the coupling of focal-adhesion proteins to actin filaments. Different classes of focal-adhesion structural and regulatory molecules exhibited varying degrees of correlated motions with actin filaments, indicating hierarchical transmission of actin motion through focal adhesions. Interactions between vinculin, talin, and actin filaments appear to constitute a slippage interface between the cytoskeleton and integrins, generating a molecular clutch that is regulated during the morphodynamic transitions of cell migration.     

Requirement of JNK2 for scavenger receptor A-mediated foam cell formation in atherogenesis

In vitro studies suggest a role for c-Jun N-terminal kinases (JNKs) in proatherogenic cellular processes. We show that atherosclerosis-prone ApoE-/- mice simultaneously lacking JNK2 (ApoE-/- JNK2-/- mice), but not ApoE-/- JNK1-/- mice, developed less atherosclerosis than do ApoE-/- mice. Pharmacological inhibition of JNK activity efficiently reduced plaque formation. Macrophages lacking JNK2 displayed suppressed foam cell formation caused by defective uptake and degradation of modified lipoproteins and showed increased amounts of the modified lipoprotein-binding and -internalizing scavenger receptor A (SR-A), whose phosphorylation was markedly decreased. Macrophage-restricted deletion of JNK2 was sufficient to decrease atherogenesis. Thus, JNK2-dependent phosphorylation of SR-A promotes uptake of lipids in macrophages, thereby regulating foam cell formation, a critical step in atherogenesis.     

Fluctuation superconductivity in mesoscopic aluminum rings

Fluctuations are important near phase transitions, where they can be difficult to describe quantitatively. Superconductivity in mesoscopic rings is particularly intriguing because the critical temperature is an oscillatory function of magnetic field. There is an exact theory for thermal fluctuations in one-dimensional superconducting rings, which are therefore expected to be an excellent model system. We measured the susceptibility of many rings, one ring at a time, by using a scanning superconducting quantum interference device that can isolate magnetic signals that are seven orders of magnitude smaller than applied flux. We find that the fluctuation theory describes the results and that a single parameter characterizes the ways in which the fluctuations are especially important at magnetic fields where the critical temperature is suppressed.