A G-protein-coupled neuropeptide Y-like receptor suppresses behavioral and sensory response to multiple stressful stimuli in Drosophila.

Recent studies suggest that human neuropeptide Y (NPY) plays a prominent role in management of stress response and emotion, and higher NPY levels observed in combat-exposed veterans may help coping with posttraumatic stress. Neuropeptide F (NPF), the counterpart of NPY in Drosophila melanogaster, also displays parallel activities, including promotion of resilience to diverse stressors and prevention of uncontrolled aggressive behavior. However, it remains unclear how NPY family peptides modulate physical and emotional responses to various stressors.

Protein kinase C deficiency-induced alcohol insensitivity and underlying cellular targets in Drosophila.

Multiple subtypes of protein kinase C (PKC) isozymes are implicated in various neurological disorders including alcohol insensitivity, a trait strongly associated with alcoholism in humans, but molecular and cellular mechanisms underlying the PKC activities remain poorly understood. Here we show that functional knockdown of conventional, novel or atypical PKC in the fly nervous system each resulted in alcohol insensitivity. Neuroanatomical mapping of conventional Ca(2+)-sensitive PKC53E activity uncovers a previously uncharacterized role of Drosophila serotonin neurons in alcohol sensitivity.

Product release rather than chelation determines metal specificity for ferrochelatase.

Ferrochelatase (protoheme ferrolyase, E.C. 4.

Identification of Escherichia coli HemG as a novel, menadione-dependent flavodoxin with protoporphyrinogen oxidase activity.

Protoporphyrinogen oxidase (PPO, EC 1.3.3.

A protein kinase C activity localized to neuropeptide Y-like neurons mediates ethanol intoxication in Drosophila melanogaster.

Neuropeptide Y (NPY) regulates acute ethanol sensitivity and voluntary alcohol consumption in rodents. In Drosophila melanogaster, NPY-like neuropeptide F (NPF) and its receptor NPFR1 display a parallel function, suggesting that an evolutionarily conserved mechanism may underlie similar behavioral effects of ethanol in diverse organisms. We have used the fly model to uncover novel genes and molecular pathways important for acute ethanol response.

Depiction of gene-environment relationships in online medical recommendations.

Purpose: This study examines the presentation of genetic and behavioral causation and prevention in websites that make medical recommendations to lay people for four diseases: heart disease, diabetes, lung cancer, and depression.

Methods: A sample of 73 online medical recommendations from major health institutions and information portals were retrieved for content analysis, with a focus on the depiction of gene-environment relationships.

Results: The results show a clear preponderance of behavioral causation and recommendations.

A pi-helix switch selective for porphyrin deprotonation and product release in human ferrochelatase.

Ferrochelatase (protoheme ferrolyase, EC 4.99.1.

Co-regulation of cold-resistant food acquisition by insulin- and neuropeptide Y-like systems in Drosophila melanogaster.

To survive, food-deprived animals may be forced to forage under hostile conditions. We attempt to use genetically tractable Drosophila melanogaster as a model to elucidate molecular and neural mechanisms that drive a forager to engage in risk-prone food acquisition. Here we describe a paradigm for assessing hunger-driven food acquisition by fly larvae at a deleteriously cold temperature.

Altered orientation of active site residues in variants of human ferrochelatase. Evidence for a hydrogen bond network involved in catalysis.

Ferrochelatase catalyzes the terminal step in heme biosynthesis, the insertion of ferrous iron into protoporphyrin to form protoheme IX. The crystal structures of human ferrochelatase both with and without the protoporphyrin substrate bound have been determined previously. The substrate-free enzyme has an open active site pocket, while in the substrate-bound enzyme, the active site pocket is closed around the porphyrin macrocycle and a number of active site residues have reoriented side chains.

A new class of [2Fe-2S]-cluster-containing protoporphyrin (IX) ferrochelatases.

Protoporphyrin (IX) ferrochelatase catalyses the insertion of ferrous iron into protoporphyrin IX to form haem. These ferrochelatases exist as monomers and dimers, both with and without [2Fe-2S] clusters. The motifs for [2Fe-2S] cluster co-ordination are varied, but in all cases previously reported, three of the four cysteine ligands are present in the 30 C-terminal residues and the fourth ligand is internal.

Regulation of aversion to noxious food by Drosophila neuropeptide Y- and insulin-like systems.

Omnivores, including humans, have an inborn tendency to avoid noxious or unfamiliar foods. Such defensive foraging behaviors are modifiable, however, in response to physiological needs. Here we describe a method for assessing risk-sensitive food acquisition in Drosophila melanogaster.

Regulation of hunger-driven behaviors by neural ribosomal S6 kinase in Drosophila.

Hunger elicits diverse, yet coordinated, adaptive responses across species, but the underlying signaling mechanism remains poorly understood. Here, we report on the function and mechanism of the Drosophila insulin-like system in the central regulation of different hunger-driven behaviors. We found that overexpression of Drosophila insulin-like peptides (DILPs) in the nervous system of fasted larvae suppressed the hunger-driven increase of ingestion rate and intake of nonpreferred foods (e.

A continuous fluorimetric assay for protoporphyrinogen oxidase by monitoring porphyrin accumulation.

A continuous spectrofluorimetric assay for protoporphyrinogen oxidase (PPO, EC 1.3.3.

Production and characterization of erythropoietic protoporphyric heterodimeric ferrochelatases.

Mutations resulting in diminished activity of the dimeric enzyme ferrochelatase are a prerequisite for the inherited disorder erythropoietic protoporphyria (EPP). Patients with clinical EPP have only 10% to 30% of normal levels of ferrochelatase activity, and although many patients with EPP have one mutant allele and one "low-expression" normal allele, the possibility remains that, for some, low ferrochelatase activity may result from an EPP mutation that has an impact on both subunits of the wild-type/mutant heterodimer. Here we present data for 12 ferrochelatase wild-type/EPP mutant heterodimers showing that some mutations result in heterodimers with the residual activity anticipated from individual constituents, whereas others result in heterodimers with significantly lower activity than would be predicted.

Drosophila neuropeptide F and its receptor, NPFR1, define a signaling pathway that acutely modulates alcohol sensitivity.

Alcohol is likely to affect neurons nonselectively, and the understanding of its action in the CNS requires elucidation of underlying neuronal circuits and associated cellular processes. We have identified a Drosophila signaling system, comprising neurons expressing neuropeptide F (NPF, a homolog of mammalian neuropeptide Y) and its receptor, NPFR1, that acutely mediates sensitivity to ethanol sedation. Flies deficient in NPF/NPFR1 signaling showed decreased alcohol sensitivity, whereas those overexpressing NPF exhibited the opposite phenotype.

Examination of mitochondrial protein targeting of haem synthetic enzymes: in vivo identification of three functional haem-responsive motifs in 5-aminolaevulinate synthase.

The initial and the terminal three enzymes of the mammalian haem biosynthetic pathway are nuclear encoded, cytoplasmically synthesized and post-translationally translocated into the mitochondrion. The first enzyme, ALAS (5-aminolaevulinate synthase), occurs as an isoenzyme encoded on different chromosomes and is synthesized either as a housekeeping protein (ALAS-1) in all non-erythroid cell types, or only in differentiating erythroid precursor cells (ALAS-2). Both ALAS proteins possess mitochondrial targeting sequences that have putative haem-binding motifs.

Movement-related modulation of vibrotactile detection thresholds in the human orofacial system.

By virtue of the direct coupling between circumoral skin and the underlying orofacial musculature, mechanosensation associated with precise orofacial force control may contribute significantly to processes associated with perception, proprioception, and sensorimotor control in this region. The purpose of this study was to assess lower lip (LL) vibratory detection thresholds of adult subjects during the simultaneous performance of a visually guided and continuous lip motor control task. Vibrotactile inputs were delivered to the right LL vermilion at test frequencies of 5, 10, 50, 150, 250, and 300 Hz.

Characterization of a human and mouse tetrapyrrole-binding protein.

The cDNA for p22HBP has been cloned from human and mouse, and the protein expressed, purified, and characterized. Both mouse and human proteins bind heme and porphyrins with micromolar K(d)s, are highly homologous, monomeric, and soluble, and have a cytoplasmic location. The proteins bind metalloporphyrins, free porphyrins, and N-methylprotoporphyrin with similar affinities, and mutations of a selected set of putative metal ligating residues did not have any significant effect on the measured K(d)s.

Terminal steps of haem biosynthesis.

The terminal three steps in haem biosynthesis are the oxidative decarboxylation of coproporphyrinogen III to protoporphyrinogen IX, followed by the six-electron oxidation of protoporphyrinogen to protoporphyrin IX, and finally the insertion of ferrous iron to form haem. Interestingly, Nature has evolved distinct enzymic machinery to deal with the antepenultimate (coproporphyrinogen oxidase) and penultimate (protoporphyrinogen oxidase) steps for aerobic compared with anaerobic organisms. The terminal step is catalysed by the enzyme ferrochelatase.

Identification of [2Fe-2S] clusters in microbial ferrochelatases.

The terminal enzyme of heme biosynthesis, ferrochelatase (EC 4.99.1.

A mouse model for South African (R59W) variegate porphyria: construction and initial characterization.

Variegate porphyria is inherited as an autosomal dominant disease with variable penetrance. It is characterized clinically by photocutaneous sensitivity and acute neurovisceral attacks, and biochemically by abnormal porphyrin excretion in the urine and feces. While the world-wide incidence of variegate porphyria is relatively low, in South Africa it is one of the most common genetic diseases in humans.

Characterization of the mouse protoporphyrinogen oxidase gene.

The murine protoporphyrinogen oxidase gene has been isolated, characterized and localized. The gene spans 4.2 kb, is comprised of 13 exons and 12 introns, and is located on chromosome 1 in band 1 H2.