The function of Drosophila larval class IV dendritic arborization sensory neurons in the larval-pupal transition is separable from their function in mechanical nociception responses.

The sensory and physiological inputs which govern the larval-pupal transition in Drosophila, and the neuronal circuity that integrates them, are complex. Previous work from our laboratory identified a dosage-sensitive genetic interaction between the genes encoding the Rho-GEF Trio and the zinc-finger transcription factor Sequoia that interfered with the larval-pupal transition. Specifically, we reported heterozygous mutations in sequoia (seq) dominantly exacerbated the trio mutant phenotype, and this seq-enhanced trio mutant genotype blocked the transition of third instar larvae from foragers to wanderers, a requisite behavioral transition prior to pupation.

An allele of sequoia dominantly enhances a trio mutant phenotype to influence Drosophila larval behavior.

The transition of Drosophila third instar larvae from feeding, photo-phobic foragers to non-feeding, photo-neutral wanderers is a classic behavioral switch that precedes pupariation. The neuronal network responsible for this behavior has recently begun to be defined. Previous genetic analyses have identified signaling components for food and light sensory inputs and neuropeptide hormonal outputs as being critical for the forager to wanderer transition.

The Abelson tyrosine kinase, the Trio GEF and Enabled interact with the Netrin receptor Frazzled in Drosophila.

The attractive Netrin receptor Frazzled (Fra), and the signaling molecules Abelson tyrosine kinase (Abl), the guanine nucleotide-exchange factor Trio, and the Abl substrate Enabled (Ena), all regulate axon pathfinding at the Drosophila embryonic CNS midline. We detect genetic and/or physical interactions between Fra and these effector molecules that suggest that they act in concert to guide axons across the midline. Mutations in Abl and trio dominantly enhance fra and Netrin mutant CNS phenotypes, and fra;Abl and fra;trio double mutants display a dramatic loss of axons in a majority of commissures.

Interactions between the secreted protein Amalgam, its transmembrane receptor Neurotactin and the Abelson tyrosine kinase affect axon pathfinding.

Two novel dosage-sensitive modifiers of the Abelson tyrosine kinase (Abl) mutant phenotype have been identified. Amalgam (Ama) is a secreted protein that interacts with the transmembrane protein Neurotactin (Nrt) to promote cell:cell adhesion. We have identified an unusual missense ama allele, ama(M109), which dominantly enhances the Abl mutant phenotype, affecting axon pathfinding.

The influence of medical information on the perioperative course of stress in cardiac surgery patients.

Unlabelled: Cardiac surgery correlates with increased perioperative stress and anxiety. We tested whether preoperative extensive oral information in combination with more personal attention by the surgeon is associated with any effect on patients' perioperative stress, anxiety, and well-being. Sixty patients awaiting open heart surgery were divided into two groups.