Search results for "MELANOGASTER"

Effets Biologiques d'extraits Aqueux de Peganum Harmala ( L. ) ( Zygophyllaceae ) sur la Mortalité et le Développement Larvaire de Drosophila Melanog…

2013

UDP-glucosyltransferase activity toward exogenous substrates in Drosophila melanogaster.

1991

To investigate the capacity of Drosophila extracts to glucosylate exogenous substrates we have developed a fast and sensitive method for the detection of UDP-glucosyltransferase activity using 4-nitrophenol, 1-naphthol, or 2-naphthol as substrates. High-performance liquid chromatography was used to separate and quantitate the reaction products, allowing detection of activities that produced as little as 1 pmol of 2-naphthol glucoside (fluorescence detection) or 16 pmol of 4-nitrophenol glucoside (absorbance detection). Optimal activity was found at 43 degrees C and alkaline pH. The affinity of the Drosophila enzyme was 250-fold higher for 1-naphthol or 2-naphthol (Km approximately 4 microM)…

Dysfunction of Oskyddad causes Harlequin-type ichthyosis-like defects in Drosophila melanogaster.

2020

Prevention of desiccation is a constant challenge for terrestrial organisms. Land insects have an extracellular coat, the cuticle, that plays a major role in protection against exaggerated water loss. Here, we report that the ABC transporter Oskyddad (Osy)—a human ABCA12 paralog—contributes to the waterproof barrier function of the cuticle in the fruit fly Drosophila melanogaster. We show that the reduction or elimination of Osy function provokes rapid desiccation. Osy is also involved in defining the inward barrier against xenobiotics penetration. Consistently, the amounts of cuticular hydrocarbons that are involved in cuticle impermeability decrease markedly when Osy activity is reduced. …

Comparison of inter- and intraspecies variation in humans and fruit flies

2015

AbstractVariation is essential to species survival and adaptation during evolution. This variation is conferred by the imperfection of biochemical processes, such as mutations and alterations in DNA sequences, and can also be seen within genomes through processes such as the generation of antibodies. Recent sequencing projects have produced multiple versions of the genomes of humans and fruit flies (Drosophila melanogaster). These give us a chance to study how individual gene sequences vary within and between species. Here we arranged human and fly genes in orthologous pairs and compared such within-species variability with their degree of conservation between flies and humans. We observed …

aPKCζ cortical loading is associated with Lgl cytoplasmic release and tumor growth in Drosophila and human epithelia

2007

Atypical protein kinase C (aPKC) and Lethal giant larvae (Lgl) regulate apical-basal polarity in Drosophila and mammalian epithelia. At the apical domain, aPKC phosphorylates and displaces Lgl that, in turn, maintains aPKC inactive at the basolateral region. The mutual exclusion of these two proteins seems to be crucial for the correct epithelial structure and function. Here we show that a cortical aPKC loading induces Lgl cytoplasmic release and massive overgrowth in Drosophila imaginal epithelia, whereas a cytoplasmic expression does not alter proliferation and epithelial overall structure. As two aPKC isoforms (iota and zeta) exist in humans and we previously showed that Drosophila Lgl i…

Inducing Cold-Sensitivity in the Frigophilic Fly Drosophila montana by RNAi.

2016

Cold acclimation is a critical physiological adaptation for coping with seasonal cold. By increasing their cold tolerance individuals can remain active for longer at the onset of winter and can recover more quickly from a cold shock. In insects, despite many physiological studies, little is known about the genetic basis of cold acclimation. Recently, transcriptomic analyses in Drosophila virilis and D. montana revealed candidate genes for cold acclimation by identifying genes upregulated during exposure to cold. Here, we test the role of myo-inositol-1-phosphate synthase (Inos), in cold tolerance in D. montana using an RNAi approach. D. montana has a circumpolar distribution and overwinters…

Identification and characterisation of the dopamine receptor II from the cat flea Ctenocephalides felis (CfDopRII)

2006

International audience; G protein-coupled receptors (GPCRs) represent a protein family with a wide range of functions. Approximately 30% of human drug targets are GPCRs, illustrating their pharmaceutical relevance. In contrast, the knowledge about invertebrate GPCRs is limited and is mainly restricted to model organisms like Drosophila melanogaster and Caenorhabditis elegans. Especially in ectoparasites like ticks and fleas, only few GPCRs are characterised. From the cat flea Ctenocephalides felis, a relevant parasite of cats and dogs, no GPCRs are known so far. Thus, we performed a bioinformatic analysis of available insect GPCR sequences from the honeybee Apis mellifera, the mosquito Anop…

Nuclear receptors modulate the interaction of Sp1 and GC-rich DNA via ternary complex formation

2000

Binding sites for transcription factor Sp1have been implicated in the transcriptional regulation of several genes by hormones or vitamins, and here we show that a GC-rich element contributes to the retinoic acid response of the interleukin 1β promoter. To explain such observations, it has been proposed that nuclear receptors can interact with Sp1 bound to GC-rich DNA. However, evidence supporting this model has remained indirect. So far, nuclear receptors have not been detected in a complex with Sp1 and GC-rich DNA, and the expected ternary complexes in non-denaturing gels were not seen. In search for these missing links we found that nuclear receptors [retinoic acid receptor (RAR), thyroid…

Timing of identity: spatiotemporal regulation of hunchback in neuroblast lineages of Drosophila by Seven-up and Prospero.

2006

Neural stem cells often generate different cell types in a fixed birth order as a result of temporal specification of the progenitors. In Drosophila, the first temporal identity of most neural stem cells(neuroblasts) in the embryonic ventral nerve cord is specified by the transient expression of the transcription factor Hunchback. When reaching the next temporal identity, this expression is switched off in the neuroblasts by seven up (svp) in a mitosis-dependent manner, but is maintained in their progeny (ganglion mother cells). We show that svpmRNA is already expressed in the neuroblasts before this division. After mitosis, Svp protein accumulates in both cells, but the downregulation of h…

The ladybird homeobox genes are essential for the specification of a subpopulation of neural cells

2004

AbstractIn Drosophila, neurons and glial cells are produced by neural precursor cells called neuroblasts (NBs), which can be individually identified. Each NB generates a characteristic cell lineage specified by a precise spatiotemporal control of gene expression within the NB and its progeny. Here we show that the homeobox genes ladybird early and ladybird late are expressed in subsets of cells deriving from neuroblasts NB 5-3 and NB 5-6 and are essential for their correct development. Our analysis revealed that ladybird in Drosophila, like their vertebrate orthologous Lbx1 genes, play an important role in cell fate specification processes. Among those cells that express ladybird are NB 5-6…