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The Keap1-Nrf2 pathway is a major upstream regulator of xenobiotic detoxification. In Drosophila melanogaster Meigen, targeted expression of Keap1 and CncC (the latter the orthologue of human Nrf2) in the Malpighian (renal) tubules is known to confer resistance to lethal doses of the pesticide malathion, which is metabolized into organic anions. Dietary exposure to organic anions such as salicylate (10 mm) causes increases in the fluid secretion rate and salicylate flux across Malpighian tubules. In the present study, salicylate-selective microelectrodes and Ramsay assays are used to determine the role of Keap1/Nrf2 in regulating these responses. Genetic manipulations designed to increase Nrf2 activity (by knockdown of the repressor Keap1 or overexpression of the Nrf2 coactivator MafS) or to decrease Nrf2 activity (by overexpression of Keap1) are also studied. Although the results of the Keap1 manipulations are inconclusive, there is no increase in the fluid secretion rate or salicylate flux in tubules isolated from flies in which MafS expression is increased.

Mandacaru (Cereus jamacaru DC - Cactaceae) possesses peculiar physiological and morphological characteristics that allow it to withstand long periods of scarcity and to adapt to different environments. Several uses have also been reported for the species from the 17th century to the present day. Given this history and the importance of the usage of mandacaru, the present investigation aimed to gather information about its uses from different documentary sources, and to perform a comparative analysis between past and present uses. Historia Naturalis Brasiliae by Piso and Marcgrave (17th century) served as the primary source, while information on labels of exsicates in botanical collections, basic scientific literature, and applications for patent filing at INPI, EPO, USPTO, WIPO (until October 2017), served as secondary sources. According to established categories of use, both the primary source and secondary sources revealed that mandacaru has had several applications, among which use for food and medicinal purposes stand out. Other uses, such as ornamental, magical-religious, civil construction and rural fences, were also reported. Despite the numerous references of usage in the documentary sources, knowledge about the potential use of C. jamacaru is not widely spread nor well protected.

We report a quantitative analysis of the modulation of locomotion by light in the Drosophila larva. The photobehavior of wild type larvae and of larvae carrying mutations altering various aspects of locomotion was evaluated in an assay that exposes individual animals to intermittent pulses of dark and light (ON/OFF assay). The application of the Dynamic Image Analysis System for the analysis of larval movement in the ON/OFF assay allowed a detailed description of the behavioral repertoire underlying the modulation of larval motion by light. We established that the larval response to light is characterized by decreased frequency of peristaltic contractions in addition to increased direction change and pausing. Moreover, using various mutant strains we show that this approach allows the detection of a response to light in mutant larvae whose locomotion is severely reduced and uncoordinated, mutants that would otherwise have been considered non-responders in this assay.

The larval visual system of Drosophila melanogaster consists of two bilateral clusters of 12 photoreceptors, which express Rhodopsin 5 and 6 (Rh5 and Rh6) in a non-overlapping manner. These neurons send their axons in a fascicle, the larval optic nerve (LON), which terminates in the larval optic neuropil. The LON is required for the development of a serotonergic arborization originating in the central brain and for the development of the dendritic tree of the circadian pacemakers, the small ventral lateral neurons (LNv) [Malpel, S., Klarsfeld, A., Rouyer, F., 2002. Larval optic nerve and adult extra-retinal photoreceptors sequentially associate with clock neurons during Drosophila brain development. Development 129, 1443–1453; Mukhopadhyay, M., Campos, A.R., 1995. The larval optic nerve is required for the development of an identified serotonergic arborization in Drosophila melanogaster . Dev. Biol., 169, 629–643]. Here, we show that both Rh5- and Rh6-expressing fibers overlap equally with the 5-HT arborization and that it, in turn, also contacts the dendritic tree of the LNv. The experiments described here aimed at determining whether Rh5- or Rh6-expressing fibers, as well as the LNv, influence the development of this serotonergic arborization. We conclude that Rh6-expressing fibers play a unique role in providing a signal required for the outgrowth and branching of the serotonergic arborization. Moreover, the innervation of the larval optic neuropil by the 5-HT arborization depends on intact Rac function. A possible role for these serotonergic processes in modulating the larval circadian rhythmicity and photoreceptor function is discussed.

The Drosophila melanogaster larval photosensory organ that mediates the response to light consists of bilaterally symmetrical clusters of 12 photoreceptors. These are distinguished on the basis of expression of the rhodopsins Rh5 and Rh6. The Rh6-expressing cells correspond to the Hofbauer-Buchner (H-B) eyelet found later in the posterior margin of the adult compound eye and recently shown to function as an input pathway in the entrainment of circadian rhythmicity in adult Drosophila. In addition, the axons of the larval photoreceptors are found in intimate association with a subset of the main circadian pacemaker neurons located in the developing accessory medulla, the small ventral lateral neurons (LNv). The observed spatial overlap between components of the circadian circuitry, input pathway, and pacemaker neurons—and the larval visual organ—suggest a functional relationship between these two photosensory input pathways. In this study we determined the requirement of specific rhodopsin-expressing photoreceptors including the presumptive H-B eyelet and pacemaker neurons in the larval locomotory response to visual stimuli. Our results demonstrate that two of the most important components of the neuronal circuitry underlying circadian rhythmicity in Drosophila, namely, the extraretinal H-B cluster and the circadian pacemakers, while in intimate association with the larval visual system are not required for the larval motor response to light. J. Comp. Neurol. 481:266–275, 2005. © 2004 Wiley-Liss, Inc.

We report the cloning and initial characterization of a novel gene encoding the Disco interacting protein 2 (Dip2). dip2 DNA complementary to RNA (cDNA) showed a high degree of sequence similarity to cDNAs of unknown function previously identified in humans and Caenorhabditis elegans. We have cloned the mouse homolog of the dip2 cDNA and characterized the expression of this gene by Northern blotting analysis and in situ hybridization to whole mount embryos. Our observations demonstrate that there is a remarkable degree of sequence conservation at the dip2 locus that is reflected in the nervous system-specific expression of both the Drosophila and mouse homologs.

DNA polymerase γ, Pol γ, is the key replicative enzyme in animal mitochondria. The Drosophila enzyme is a heterodimer comprising catalytic and accessory subunits of 125 kDa and 35 kDa, respectively. Both subunits have been cloned and characterized in a variety of model systems, and genetic mutants of the catalytic subunit were first identified in Drosophila , as chemically induced mutations that disrupt larval behavior ( tamas ) . Mutations in the gene encoding the accessory subunit have not yet been described in any organism. Here, we report the consequences of null mutations upon mitochondrial DNA (mtDNA) replication and morphology , cell proliferation, and organismal viability. Mutations in the accessory subunit cause lethality during early pupation, concomitant with loss of mtDNA and mitochondrial mass, and reduced cell proliferation in the central nervous system. Surprisingly, the function of the central nervous system and muscle, as assessed in a locomotion assay, are only marginally affected. This finding is in contrast to our previous findings that disruption in the function of the catalytic subunit causes severe reduction in larval locomotion. We discuss our results in the context of current hypotheses for the function of the accessory subunit in mtDNA replication.

A new assay was designed, named checker, that measures the individual response to light in the fruitfly Drosophila melanogaster larva. In this assay the Drosophila larva apparently modulates its pattern of locomotion when faced with a choice between a dark and lit environment by orienting its movement towards the dark environment. We show that, in this assay, a response to light can be measured as an increase in residence time in the dark versus the lit quadrant. Mutations that disrupt phototransduction in the adult Drosophila abolish the larval response to light, demonstrating that this larval visual function is similar to that of the adult fly. Similarly, no response to light was detected in strains where the larval visual system (photoreceptors and target area) was disrupted by a mutation in the homeobox containing gene sine oculis (so) gene. Ablation of photoreceptors by the targeted expression of the cell death gene hid under the control of the photoreceptor-specific transcription factor glass (gl) abolishes this response entirely. Finally, we demonstrate that this response to light can be mediated by rhodopsins other than the blue absorbing Rh1.

The Drosophila disconnected (disco) gene is required for the formation of appropriate connections between the larval optic nerve and its target cells in the brain. The disco gene encodes a nuclear protein with two zinc fingers, which suggests that the gene product is a transcription factor. Here, we present data supporting this notion. We find that disco expression in the optic lobe primordium, a group of cells contacted by the developing optic nerve, depends on an autoregulatory feedback loop. We show that wild-type disco function is required for maintenance of disco mRNA and protein expression in the developing optic lobe. In addition, we demonstrate that ubiquitous Disco activity supplied by a heat-inducible gene construct activates expression from the endogenous disco gene specifically in the optic lobe primordium. Consistent with a role of Disco as a transcriptional regulatory protein, we show that portions of the Disco protein are capable of activating the transcription of reporter constructs in a heterologous system. Moreover, we find that the zinc finger portion of Disco binds in vitro to sequences located near the disco transcription unit, suggesting that Disco autoregulates its transcription in the optic lobe primordium by direct binding to a regulatory element in its own promoter.

We used confocal microscopy in conjunction with specific antibodies and enhancer trap strains to investigate the development of specific neuronal connections in a simple model system, the larval visual system of Drosophila. We find that the establishment of axonal projections from the larval photoreceptor neurons to their central nervous system targets involves a series of discrete steps. During embryogenesis, the larval optic nerve contacts several different cell types, including optic lobe pioneer (OLP) neurons and a number of glial cells. We demonstrate that OLP neurons are present and project normally in glass (gl) mutant embryos in which the larval optic nerve fails to develop, suggesting that they do not depend on interactions with the larval optic nerve for differentiation and proper axonal projection. The OLPs fail to differentiate properly in disconnected (disco) mutant embryos, where appropriate connections between the larval optic nerve and its targets in the brain are not formed. The disco gene is expressed in the OLPs and may therefore act autonomously to direct the differentiation of these cells. Taken together, our results suggest that the OLPs act as an intermediate target required for the establishment of normal optic nerve projection and connectivity. © 1995 John Wiley & Sons, Inc.

SUMMARYInsects excrete a wide variety of toxins via the Malpighian (renal) tubules. Previous studies have implicated three transporters in the secretion of the organic anion (OA) methotrexate (MTX) by the Drosophila Malpighian tubule: Drosophila multidrug resistance-associated protein (dMRP, CG6214), a multidrug efflux transporter (MET, CG30344), and an organic anion transporting polypeptide 58Dc (OATP58Dc, CG3380). RNA interference (RNAi) knockdown and P-element insertion mutation of single OA transporter genes were used to evaluate the importance of these three putative transporters in the secretion of MTX by the Malpighian tubules of Drosophila melanogaster. A major finding is that genetic knockdown of a single OA transporter gene leads to reductions in the expression of at least one other OA transporter gene and in secretion of MTX by Malpighian tubules isolated from flies reared on a standard diet. The pattern of changes indicates that decreases in MTX secretion do not correspond to decreases in dMRP expression in all of the RNAi lines. Genetic knockdown of a single OA transporter gene also alters the extent of upregulation of multiple OA transporter genes in the tubules in response to dietary MTX. Knockdown of dMRP is associated with a decrease in MET expression but an increase in OATP expression when flies are reared on MTX-enriched diet. Our results indicate that dMRP and MET are not the dominant MTX transporters in the tubules when flies are reared on MTX-enriched diets. At least one additional transporter, and possibly OATP, are required for MTX secretion. The implications of our results for studies using genetic knockdown techniques to identify OA transporters in whole tissues such as Malpighian tubules are discussed.

In this paper we examine theDrosophila melanogaster larval response to light. We survey the morphology of the larval visual and motor systems in relation to larval locomotory behavior and phototaxis. In addition, this paper proposes a model of sensorimotor transformation and examines the reversal in taxis occurring at theD. melanogaster larval wnadering stage.

Mutations in the disco (disconnected) gene prevent the establishment of stable connections between the larval optic nerves, the Bolwig's nerves, and their target cells in the brain during embryonic development. The failure of this initial connection is associated with aberrant development of the optic lobes which are largely degenerate in the mutant adult fly. In order to understand the role of disco in establishing this connection, we isolated and characterized the disco gene. A 22 kb DNA fragment can completely rescue the mutant phenotype. A single transcript, 2.9 kb in length, is found in this region and is expressed throughout development of the fly. We determined the nucleotide sequence of the disco gene to be unique when compared with sequences in a number of databases. The predicted amino acid sequence contains a region with similarity to the consensus established for the zinc finger motif. Mobilization of a P-element inserted near the gene resulted in the deletion of the 5' end of the gene and produced flies indistinguishable from those carrying the disco allele.

Menin, the product of the multiple endocrine neoplasia type I gene, has been implicated in several biological processes, including the control of gene expression and apoptosis, the modulation of mitogen-activated protein kinase pathways, and DNA damage sensing or repair. In this study, we have investigated the function of menin in the model organism Drosophila melanogaster. We show that Drosophila lines overexpressing menin or an RNA interference for this gene develop normally but are impaired in their response to several stresses, including heat shock, hypoxia, hyperosmolarity and oxidative stress. In the embryo subjected to heat shock, this impairment was characterized by a high degree of developmental arrest and lethality. The overexpression of menin enhanced the expression of HSP70 in embryos and interfered with its down-regulation during recovery at the normal temperature. In contrast, the inhibition of menin with RNA interference reduced the induction of HSP70 and blocked the activation of HSP23 upon heat shock, Menin was recruited to the Hsp70 promoter upon heat shock and menin overexpression stimulated the activity of this promoter in embryos. A 70-kDa inducible form of menin was expressed in response to heat shock, indicating that menin is also regulated in conditions of stress. The induction of HSP70 and HSP23 was markedly reduced or absent in mutant embryos harboring a deletion of the menin gene. These embryos, which did not express the heat shock-inducible form of menin, were also hypersensitive to various conditions of stress. These results suggest a novel role for menin in the control of the stress response and in processes associated with the maintenance of protein integrity.

From a screen of pupal lethal lines of Drosophila melanogaster we identified a mutant strain that displayed a reproducible reduction in the larval response to light. Moreover, this mutant strain showed defects in the development of the adult visual system and failure to undergo behavioral changes characteristic of the wandering stage. The foraging third instar larvae remained in the food substrate for a prolonged period and died at or just before pupariation. Using a new assay for individual larval photobehavior we determined that the lack of response to light in these mutants was due to a primary deficit in locomotion. The mutation responsible for these phenotypes was mapped to the lethal complementation group l(2)34Dc, which we renamed tamas (translated from Sanskrit as “dark inertia”). Sequencing of mutant alleles demonstrated that tamas codes for the mitochondrial DNA polymerase catalytic subunit (DNApol-γ125).

Background The multiple endocrine neoplasia type I gene functions as a tumor suppressor gene in humans and mouse models. In Drosophila melanogaster, mutants of the menin gene (Mnn1) are hypersensitive to mutagens or gamma irradiation and have profound defects in the response to several stresses including heat shock, hypoxia, hyperosmolarity and oxidative stress. However, it is not known if the function of menin in the stress response contributes to genome stability. The objective of this study was to examine the role of menin in the control of the stress response and genome stability. Methodology/Principal Findings Using a test of loss-of-heterozygosity, we show that Drosophila strains lacking a functional Mnn1 gene or expressing a Mnn1 dsRNA display increased genome instability in response to non-lethal heat shock or hypoxia treatments. This is also true for strains lacking all Hsp70 genes, implying that a precise control of the stress response is required for genome stability. While menin is required for Hsp70 expression, the results of epistatic studies indicate that the increase in genome instability observed in Mnn1 lack-of-function mutants cannot be accounted for by mis-expression of Hsp70. Therefore, menin may promote genome stability by controlling the expression of other stress-responsive genes. In agreement with this notion, gene profiling reveals that Mnn1 is required for sustained expression of all heat shock protein genes but is dispensable for early induction of the heat shock response. Conclusions/Significance Mutants of the Mnn1 gene are hypersensitive to several stresses and display increased genome instability when subjected to conditions, such as heat shock, generally regarded as non-genotoxic. In this report, we describe a role for menin as a global regulator of heat shock gene expression and critical factor in the maintenance of genome integrity. Therefore, menin links the stress response to the control of genome stability in Drosophila melanogaster.

The embryonic lethal abnormal visual system (elav) locus in Drosophila melanogaster, a vital gene mapping within the 1B5-1B9 region of the X-chromosome has been cloned and analysed. Previous developmental analyses have shown that in addition to the embryonic requirement there is a post-embryonic requirement for elav function in the cells of the visual system. A DNA segment containing elav+ function was defined through germ line transformation experiments. This region encodes three embryonic poly(A)+ RNAs and two adult transcripts which are preferentially expressed in the head. In situ hybridization experiments clearly demonstrate that the embryonic expression of elav is restricted to the nervous system.

The larval visual system in the fruitfly Drosophila melanogaster consists of two bilateral clusters of 12 photoreceptor cells. These neurons send their axons in a fascicle, the Bolwig's nerve, toward the target area in the ventral lateral region of the brain hemispheres. We describe the development of a serotonergic arborization originating in the central brain found in the larval optic center in association with the larval optic nerve. This arborization is formed by processes from larval neurons born during embryogenesis. However, these neuronal processes do not reach their final destination, the larval optic center, until late in larval development. Using mutations that disrupt the connectivity and/or development of the larval photoreceptor cells, as well as mosaic analysis, we demonstrate that the innervation of the larval optic center by this serotonergic arborization depends upon contact with the larval optic nerve.

We report a developmental and genetic analysis of the X-linked vital locus l(1)EC7 in Drosophila melanogaster. The locus maps in the salivary band region 1B4-5 to 1B8-9, a part of the X chromosome previously shown to be essential for normal neural development. Certain mutant alleles at the locus can cause embryonic lethality, indicating that the function provided by the gene is essential during embryogenesis. A developmental analysis of gynandromorphic genetic mosaics shows that: (1) the gene function is autonomously essential in the eye; (2) the gene function is essential for normal development of the optic lobes; and (3) the gene function is not necessary in most major imaginal-disc cell derivatives with the exception of the eye disc. Conclusions from the developmental analysis of a temperature sensitive allele are consistent with those from the mosaic analysis. The embryonic lethality caused by the mutant alleles and abnormalities observed in the genetic mosaics have led us to rename the locus l(1)EC7 to elav (embryonic lethal, abnormal visual system).