Project description:The innate immune response of insects relies on several humoral and cellular mechanisms that require the activation of circulating proteases in the hemolymph to be functional. Here, we analyzed the gelatinase and caseinase activities of Drosophila larval hemolymph under normal and pathogenic conditions (bacterial lipopolysaccharides or endoparasitoid Leptopilina boulardi) using in gel zymography. Gelatinase activity was more intense than caseinase activity and qualitative and quantitative variations were observed between D. melanogaster strains and Drosophila species. Mass spectrometry identified a large number of serine proteases in gel bands equivalent to the major gelatinase and caseinase bands and of these, the most abundant and redundant were Tequila and members of the Jonah and Trypsin protease families. However, hemolymph from Tequila null mutant larvae showed no obvious changes in zymographic bands. Nor did we observe any significant changes in hemolymph gelatinases activity 24 h after injection of bacterial lipopolysaccharides or after oviposition by endoparasitoid wasps. These data confirmed that many serine proteases are present in Drosophila larval hemolymph but those with gelatinase and caseinase activity may not change drastically during the immune response.
Project description:In mammals, extracellular miRNAs circulate in biofluids as stable entities that are secreted by normal and diseased tissues, and can enter cells and regulate gene expression. Drosophila melanogaster is a proven system for the study human diseases. They have an open circulatory system in which hemolymph (HL) circulates in direct contact with all internal organs, in a manner analogous to vertebrate blood plasma. Here we show using deep sequencing that Drosophila HL contains RNase resistant, circulating miRNAs (HL-miRNAs). Limited subsets of body tissue miRNAs (BT-miRNAs) accumulated in HL, suggesting they may be specifically released from cells or particularly stable in HL. Alternatively, they might arise from specific cells such as hemocytes, in intimate contact with HL. Young and old flies accumulated unique populations HL-miRNAs, suggesting their accumulation is responsive to the physiological status of the fly. These HL-miRNAs may function in flies similarly to the miRNAs circulating in mammalian biofluids. The discovery of these HL-miRNAs will provide a new venue for health and disease-related research in Drosophila.
Project description:In mammals, extracellular miRNAs circulate in biofluids as stable entities that are secreted by normal and diseased tissues, and can enter cells and regulate gene expression. Drosophila melanogaster is a proven system for the study human diseases. They have an open circulatory system in which hemolymph (HL) circulates in direct contact with all internal organs, in a manner analogous to vertebrate blood plasma. Here we show using deep sequencing that Drosophila HL contains RNase resistant, circulating miRNAs (HL-miRNAs). Limited subsets of body tissue miRNAs (BT-miRNAs) accumulated in HL, suggesting they may be specifically released from cells or particularly stable in HL. Alternatively, they might arise from specific cells such as hemocytes, in intimate contact with HL. Young and old flies accumulated unique populations HL-miRNAs, suggesting their accumulation is responsive to the physiological status of the fly. These HL-miRNAs may function in flies similarly to the miRNAs circulating in mammalian biofluids. The discovery of these HL-miRNAs will provide a new venue for health and disease-related research in Drosophila.
Project description:We aimed at characterizing the diverse hemocyte populations present in the hemolymph of the Drosophila larvae. The hemocytes were collected from wandering larvae infested by wasp (WI) or not infested (NI). The hemocytes were then sequenced using 10x genomics technology.
Project description:We investigated the effect of Spiroplasma infection on Drosophila hemolymph protein content using Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS). To this end, we extracted total hemolymph from uninfected and infected 10 days old females. At this age, Spiroplasma is already present at high titers in the hemolymph but does not cause major deleterious phenotypes to the fly. Extraction was achieved by puncturing the thorax and drawing out with a microinjector. Four replicates were made
Project description:MicroRNAs are a class of small (~22nt) endogenous RNAs that regulate target transcript expression post-transcriptionally. Previous studies characterized age-related changes in diurnal transcript expression but it is not understood how these changes are regulated, and whether they may be attributed in part to changes in microRNA expression or activity with age. Diurnal small RNA expression changes with age were not previously studied. To interrogate changes in small RNA expression with age, we collected young (5 day) and old (55 day) Drosophila melanogaster around-the-clock and performed deep sequencing on size-selected RNA from whole heads. We find several microRNAs with changes in rhythmicity after aging, and we investigate microRNAs which are differentially expressed with age. We find that predicted targets of differentially expressed microRNAs have RNA-binding and transcription factor activity. We use a previously published method to identify mRNA transcripts which show evidence of microRNA targeting that is altered after aging, and find several that are involved in muscle development and maintenance. Finally, we identify novel microRNAs using the random-forest-based method miRWoods, which surprisingly also discovered transfer RNA-derived fragments.