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Past research has established that Drosophila gut inflammation via the dual oxidase (DUOX) regulatory pathway is induced by exposure to bacterialderived uracil, which can be secreted by allochthonous and autochthonous bacteria in the midgut. However, the effects of the inflammatory response and resulting gut dysbiosis on the courtship behavior of the Drosophila host have yet to be determined. This work studies the changes in Drosophila courtship behavior resulting from diet-based exposure to uracil, a ligand for DUOX-dependent reactive oxygen species (ROS) generation in the epithelia of the midgut. The effects of a high-uracil diet on courtship behavior were determined by comparing courtship index (CI) values of flies treated with 20 nM of uracil for 16-hr (shortterm) or 10-d (long-term) exposure to age-matched control flies. Although shortterm uracil treatment caused no change in courtship behavior, long-term uracil treatment resulted in a significant decrease in CI. This result suggests that the underlying association for the behavioral change may be influenced by gut inflammation initiated by long-term exposure to uracil. By measuring the effects of an innate immune response such as exposure to a ligand for DUOX-dependent ROS generation on the courtship index of Drosophila, the current understanding of the relationship between gut inflammation and behavioral changes in animals can be expanded. Given that prior research has also established that the DUOX-dependent response can be found in animals ranging from Drosophila to humans, the behavioral changes observed from induction of the pathway have the potential to expand this connection in the future. Keywords: inflammation, gut microbiota, courtship, In recent years, the role of microbiology in the field of neuroscience has rapidly expanded as research has focused on the connection between gut microbiota and the brain in animals. [...]

Abstract The fruit fly Drosophila melanogaster shows a bimodal circadian locomotor rhythm with peaks at lights-on and before lights-off, which are regulated by multiple clocks in the brain. Even under [...]

Abstract In constant light, where Drosophila rhythms are normally disrupted, temperature cycles induce circadian rhythms at both the molecular and behavioral level. The authors investigated the process by which the [...]

The molecular pathways involved in retrograde signal transduction at synapses and the function of retrograde communication are poorly understood. Here, we demonstrate that postsynaptic calcium [2.sup.+] ion ([Ca.sup.2+]) influx through glutamate receptors and subsequent postsynaptic vesicle fusion trigger a robust induction of presynaptic miniature release after high-frequency stimulation at Drosophila neuromuscular junctions. An isoform of the synaptotagmin family, synaptotagmin 4 (Syt 4), serves as a postsynaptic [Ca.sup.2+] sensor to release retrograde signals that stimulate enhanced presynaptic function through activation of the cyclic adenosine monophosphate (cAMP)--cAMP-dependent protein kinase pathway. Postsynaptic [Ca.sup.2+] influx also stimulates local synaptic differentiation and growth through Syt 4--mediated retrograde signals in a synapse-specific manner., Neuronal development requires coordinated signaling to orchestrate pre- and postsynaptic maturation of synaptic connections. Synapse-specific enhancement of synaptic strength as occurs during long-term potentiation (1), as well as compensatory homeostatic [...]

All animals coordinate growth and maturation to reach their final size and shape. In insects, insulin family molecules control growth and metabolism, whereas pulses of the steroid 20-hydroxyecdysone (20E) initiate major developmental transitions. We show that 20E signaling also negatively controls animal growth rates by impeding general insulin signaling involving localization of the transcription factor dFOXO and transcription of the translation inhibitor 4E-BP. We also demonstrate that the larval fat body, equivalent to the vertebrate liver, is a key relay element for ecdysone-dependent growth inhibition. Hence, ecdysone counteracts the growth-promoting action of insulins, thus forming a humoral regulatory loop that determines organismal size., In metazoans, the insulin/IGF (insulin growth factor) signaling pathway (IIS) plays a key role in regulating growth and metabolism. In Drosophila, a family of insulin-like molecules called Dilps activates a [...]

The Wnt-Wingless (Wg) pathway is one of a core set of evolutionarily conserved signaling pathways that regulates many aspects of metazoan development. Aberrant Wnt signaling has been [inked to human disease. In the present study, we used a genomewide RNA interference (RNAi) screen in Drosophila cells to screen for regulators of the Wnt pathway. We identified 238 potential regulators, which include known pathway components, genes with functions not previously linked to this pathway, and genes with no previously assigned functions. Reciprocal-Best-Blast analyses reveal that 50% of the genes identified in the screen have human orthologs, of which ~18% are associated with human disease. Functional assays of selected genes from the cell-based screen in Drosophila, mammalian cells, and zebrafish embryos demonstrated that these genes have evolutionarily conserved functions in Wnt signaling. High-throughput RNAi screens in cultured cells, followed by functional analyses in model organisms, prove to be a rapid means of identifying regulators of signaling pathways implicated in development and disease., Wnt proteins are a family of conserved signaling molecules involved in a plethora of fundamental developmental and cell biological processes such as cell proliferation, differentiation, and polarity (1-3). Several components [...]

Neuronal gene transcription is repressed in non-neuronal cells by the repressor element 1 (RE-1)-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) complex. To understand how this silencing is achieved, we examined a family of class-C RNA polymerase II (RNAPII) carboxyl-terminal domain (CTD) phosphatases [small CTD phosphatases (SCPs) 1 to 3], whose expression is restricted to non-neuronal tissues. We show that REST/NRSF recruits SCPs to neuronal genes that contain RE-1 elements, leading to neuronal gene silencing in non-neuronal cells. Phosphatase-inactive forms of SCP interfere with REST/NRSF function and promote neuronal differentiation of P19 stem cells. Likewise, small interfering RNA directed to the single Drosophila SCP unmasks neuronal gene expression in $2 cells. Thus, SCP activity is an evolutionarily conserved transcriptional regulator that acts globally to silence neuronal genes., The central nervous system is derived from neuroepithelial precursor cells within the ventricular zone that are poised to produce a wide array of specialized neuronal and glial cell types upon [...]

The polarized nature of epithelial cells is manifested by the nonrandom partitioning of organelles within the cells, the concentration of intercellular junctions at one pole, and the asymmetric distribution of proteins and lipids within the plasma membrane. These features allow epithelia to fulfill their specific tasks, such as targeted uptake and secretion of molecules and the segregation of different tissue compartments. The accessibility of Drosophila melanogaster and Caenorhabditis elegans to genetic and cell biological analyses, combined with the study of mammalian cells in culture, provides an ideal basis for understanding the mechanisms that control the establishment and maintenance of epithelial cell polarity and tissue integrity. Here, we focus on some of the best-studied junctions and membrane-associated protein complexes and their relation to cell polarity. Comparisons between fly, worm, and vertebrate epithelia reveal marked similarities with respect to the molecules used, and pronounced differences in the organization of the junctions themselves., Introduction Epithelial tissues are present in most metazoa and perform two closely related functions: They delimit compartments within tissues and participate in the controlled exchange of molecules and ions between [...]

Polarized cell movements shape the major features of the vertebrate body plan during development. The head-to-tail body axis of vertebrates is elongated in embryonic stages by 'convergent extension' tissue movements. During these movements cells intercalate between one another transverse to the elongating body axis to form a narrower, longer array. Recent discoveries show that these polarized cell movements are controlled by homologs of genes that control the polarity of epithelial cells in the developing wing and eye of the fruit fly, Drosophila., How the body plan is shaped from a cohesive aggregate of individual cells during embryogenesis is an enduring mystery. A major breakthrough is the recent discovery that homologs of genes [...]

Insecticide resistance is one of the most widespread genetic changes caused by human activity, but we still understand little about the origins and spread of resistant alleles in global populations of insects. Here, via microarray analysis of all P450s in Drosophila melanogaster, we show that DDT-R, a gene conferring resistance to DDT, is associated with overtranscription of a single cytochrome P450 gene, Cyp6g1. Transgenic analysis of Cyp6g1 shows that overtranscription of this gene alone is both necessary and sufficient for resistance. Resistance and up-regulation in Drosophila populations are associated with a single Cyp6g1 allele that has spread globally. This allele is characterized by the insertion of an Accord transposable element into the 5' end of the Cyp6g1 gene., Insecticide resistance represents an important example of natural selection. Resistance can be mediated either by changes in the sensitivity of insecticide targets in the nervous system or by metabolism of [...]

Heat-shock proteins (Hsps) are important for protecting cells against high temperature and other stresses (Lindquist and Craig 1988; Parsell et al. 1993; Morimoto et al. 1994), as suggested by their [...]

One of the most profound issues in experimental evolutionary biology has been the relationship between the genetic variance-covariance matrix of a set of characters and their long-term evolution. Under one [...]

Underpinning many evolutionary arguments is the concept that species trade off one ability as another is improved. Within a species, understanding such trade-offs can provide insight into how the resulting [...]

Abstract. - Two sets of three replicate lines of Drosophila melanogaster were artificially selected by reproduction at either a |young' or an |old' age. The pure lines, the hybrids between [...]

Abstract. - Populations of Drosophila melanogaster that had been selected for divergent rates of senescence were compared with respect to age-specific male mating ability. The competitive mating ability of males [...]