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G3 (Bethesda, Md.) May 2020Trypanosomatid parasites are causative agents of important human and animal diseases such as sleeping sickness and leishmaniasis. Most trypanosomatids are transmitted to...
Trypanosomatid parasites are causative agents of important human and animal diseases such as sleeping sickness and leishmaniasis. Most trypanosomatids are transmitted to their mammalian hosts by insects, often belonging to Diptera (or true flies). With resistance to both vector-targeted pesticides and trypanocidal drugs being reported, there is a need for novel transmission blocking strategies to be developed. Studies using the blood-feeding vectors themselves are not broadly accessible, as such, new model systems are being developed to unpick insect-trypanosmatids interactions. One such case is the interactions between the model dipteran and its natural trypanosomatid Our previous work has found that much of the transcriptomic changes triggered in after ingestion by reflect what is known for disease-causing trypanosomatids. Here we describe a set of tools to genetically manipulate the parasite and therefore create a truly tractable insect-parasite interaction system from both sides of this association. These include transgenic fluorescently tagged parasites to follow infection dynamics in the fly gut as well as iterations of plasmids that can be used for generating knock-in and knock-out strains. The tools presented in this short report will facilitate further characterization of trypanosomatid establishment in a model dipteran.
Topics: Animals; Drosophila; Drosophila melanogaster; Insecta; Trypanosomatina
PubMed: 32205316
DOI: 10.1534/g3.120.401048 -
ENeuro Jan 2023Inhibitory interneurons are important for neuronal circuit function. They regulate sensory inputs and enhance output discriminability (Olsen and Wilson, 2008; Root et...
Inhibitory interneurons are important for neuronal circuit function. They regulate sensory inputs and enhance output discriminability (Olsen and Wilson, 2008; Root et al., 2008; Olsen et al., 2010). Often, the identities of interneurons can be determined by location and morphology, which can have implications for their functions (Wachowiak and Shipley, 2006). While most interneurons fire traditional action potentials, many are nonspiking. These can be seen in insect olfaction (Laurent and Davidowitz, 1994; Husch et al., 2009; Tabuchi et al., 2015) and the vertebrate retina (Gleason et al., 1993). Here, we present the novel observation of nonspiking inhibitory interneurons in the antennal lobe (AL) of the adult fruit fly, These neurons have a morphology where they innervate a patchwork of glomeruli. We used electrophysiology to determine whether their nonspiking characteristic is because of a lack of sodium current. We then used immunohistochemsitry and hybridization to show this is likely achieved through translational regulation of the voltage-gated sodium channel gene, Using calcium imaging, we explored how these cells respond to odors, finding regional isolation in their responses' spatial patterns. Further, their response patterns were dependent on both odor identity and concentration. Thus, we surmise these neurons are electrotonically compartmentalized such that activation of the neurites in one region does not propagate across the whole antennal lobe. We propose these neurons may be the source of intraglomerular inhibition in the AL and may contribute to regulation of spontaneous activity within glomeruli.
Topics: Animals; Drosophila; Drosophila melanogaster; Interneurons; Neurons; Action Potentials; Odorants
PubMed: 36650069
DOI: 10.1523/ENEURO.0109-22.2022 -
The Journal of Experimental Biology Feb 2021The gut microbiome has been proposed to influence diverse behavioral traits of animals, although the experimental evidence is limited and often contradictory. Here, we...
The gut microbiome has been proposed to influence diverse behavioral traits of animals, although the experimental evidence is limited and often contradictory. Here, we made use of the tractability of for both behavioral analyses and microbiome studies to test how elimination of microorganisms affects a number of behavioral traits. Relative to conventional flies (i.e. with unaltered microbiome), microbiologically sterile (axenic) flies displayed a moderate reduction in memory performance in olfactory appetitive conditioning and courtship assays. The microbiological status of the flies had a small or no effect on anxiety-like behavior (centrophobism) or circadian rhythmicity of locomotor activity, but axenic flies tended to sleep for longer and displayed reduced sleep rebound after sleep deprivation. These last two effects were robust for most tests conducted on both wild-type Canton S and strains, as well for tests using an isogenized panel of flies with mutations in the gene, which causes altered circadian rhythmicity. Interestingly, the effect of absence of microbiota on a few behavioral features, most notably instantaneous locomotor activity speed, varied among wild-type strains. Taken together, our findings demonstrate that the microbiome can have subtle but significant effects on specific aspects of behavior, some of which are dependent on genetic background.
Topics: Animals; Circadian Rhythm; Drosophila; Drosophila melanogaster; Gastrointestinal Microbiome; Memory; Sleep
PubMed: 33376141
DOI: 10.1242/jeb.233619 -
Current Biology : CB Jan 2017Wolbachia are widespread endosymbiotic bacteria found in terrestrial arthropods and filarial nematodes [1]. In insects, Wolbachia generally rely on diverse strategies to...
Wolbachia are widespread endosymbiotic bacteria found in terrestrial arthropods and filarial nematodes [1]. In insects, Wolbachia generally rely on diverse strategies to manipulate their host's reproduction and favor their own vertical transmission through infected eggs [2]. One such mechanism is a sterility syndrome called 'cytoplasmic incompatibility'. Cytoplasmic incompatibility occurs at fertilization, when a spermatozoon from a Wolbachia-infected male fertilizes an uninfected egg. In this case, sperm-derived chromosomes fail to separate normally at the first zygotic division, thus preventing the development of a diploid embryo [3]. Moreover, the presence of Wolbachia in females rescues the integration of paternal chromosomes in the zygote and allows the development of a viable, infected individual. Although the molecular basis of cytoplasmic incompatibility is still unknown, a current model implies the existence of Wolbachia-induced reversible modifications on sperm DNA or chromatin that must be eliminated or neutralized shortly after fertilization by rescuing Wolbachia factors present in infected eggs [4]. In a recent Current Biology paper [5], Stéphanie Pontier and François Schweisguth recently challenged this model by proposing that Wolbachia perturbs a pheromone-based communication between male and female pupae in Drosophila melanogaster and Drosophila simulans, which controls the "compatibility range" of male and female gametes. However, we fail to detect any influence of pupal communication on cytoplasmic incompatibility in Drosophila simulans as well as in the parasitoid wasp Nasonia vitripennis. Our results thus question the robustness of their model.
Topics: Animals; Cytoplasm; Drosophila; Drosophila melanogaster; Female; Male; Pupa; Wolbachia
PubMed: 28118585
DOI: 10.1016/j.cub.2016.12.012 -
Current Biology : CB Aug 2020Three new studies use a whole adult brain electron microscopy volume to reveal new long-range connectivity maps of complete populations of neurons in olfactory,...
Three new studies use a whole adult brain electron microscopy volume to reveal new long-range connectivity maps of complete populations of neurons in olfactory, thermosensory, hygrosensory, and memory systems in the fly Drosophila melanogaster.
Topics: Animals; Brain; Connectome; Drosophila; Drosophila melanogaster; Neurons
PubMed: 32810456
DOI: 10.1016/j.cub.2020.06.068 -
Development Genes and Evolution Jan 2018Deciphering the evolution of morphological structures is a remaining challenge in the field of developmental biology. The respiratory structures of insect eggshells,...
Deciphering the evolution of morphological structures is a remaining challenge in the field of developmental biology. The respiratory structures of insect eggshells, called the dorsal appendages, provide an outstanding system for exploring these processes since considerable information is known about their patterning and morphogenesis in Drosophila melanogaster and dorsal appendage number and morphology vary widely across Drosophilid species. We investigated the patterning differences that might facilitate morphogenetic differences between D. melanogaster, which produces two oar-like structures first by wrapping and then elongating the tubes via cell intercalation and cell crawling, and Scaptodrosophila lebanonensis, which produces a variable number of appendages simply by cell intercalation and crawling. Analyses of BMP pathway components thickveins and P-Mad demonstrate that anterior patterning is conserved between these species. In contrast, EGF signaling exhibits significant differences. Transcripts for the ligand encoded by gurken localize similarly in the two species, but this morphogen creates a single dorsolateral primordium in S. lebanonensis as defined by activated MAP kinase and the downstream marker broad. Expression patterns of pointed, argos, and Capicua, early steps in the EGF pathway, exhibit a heterochronic shift in S. lebanonensis relative to those seen in D. melanogaster. We demonstrate that the S. lebanonensis Gurken homolog is active in D. melanogaster but is insufficient to alter downstream patterning responses, indicating that Gurken-EGF receptor interactions do not distinguish the two species' patterning. Altogether, these results differentiate EGF signaling patterns between species and shed light on how changes to the regulation of patterning genes may contribute to different tube-forming mechanisms.
Topics: Animals; Body Patterning; Bone Morphogenetic Proteins; Drosophila Proteins; Drosophila melanogaster; Drosophilidae; Epidermal Growth Factor; Female; HMGB Proteins; Male; Oogenesis; Repressor Proteins; Transcription Factors; Transforming Growth Factor alpha
PubMed: 29264645
DOI: 10.1007/s00427-017-0601-8 -
Cell Metabolism Feb 2018While the gut microbiome largely benefits host physiology, the impact of symbiosis on bacterial fitness has not been rigorously investigated. In this issue, Storelli...
While the gut microbiome largely benefits host physiology, the impact of symbiosis on bacterial fitness has not been rigorously investigated. In this issue, Storelli et al. (2018) provide evidence that Drosophila actively cultivate a relationship with the growth-promoting bacterium Lactobacillus plantarum, delivering mutual benefits under nutrient-poor conditions.
Topics: Animals; Bacteria; Drosophila; Drosophila melanogaster; Lactobacillus plantarum; Symbiosis
PubMed: 29414679
DOI: 10.1016/j.cmet.2018.01.010 -
Proceedings of the National Academy of... May 2018
Topics: Animals; Diet; Drosophila; Drosophila melanogaster; Gastrointestinal Tract; Microbiota
PubMed: 29735646
DOI: 10.1073/pnas.1804948115 -
Sleep Mar 2021Sleep loss and aging impair hippocampus-dependent Spatial Learning in mammalian systems. Here we use the fly Drosophila melanogaster to investigate the relationship...
Sleep loss and aging impair hippocampus-dependent Spatial Learning in mammalian systems. Here we use the fly Drosophila melanogaster to investigate the relationship between sleep and Spatial Learning in healthy and impaired flies. The Spatial Learning assay is modeled after the Morris Water Maze. The assay uses a "thermal maze" consisting of a 5 × 5 grid of Peltier plates maintained at 36-37°C and a visual panorama. The first trial begins when a single tile that is associated with a specific visual cue is cooled to 25°C. For subsequent trials, the cold tile is heated, the visual panorama is rotated and the flies must find the new cold tile by remembering its association with the visual cue. Significant learning was observed with two different wild-type strains-Cs and 2U, validating our design. Sleep deprivation prior to training impaired Spatial Learning. Learning was also impaired in the classic learning mutant rutabaga (rut); enhancing sleep restored learning to rut mutants. Further, we found that flies exhibited a dramatic age-dependent cognitive decline in Spatial Learning starting at 20-24 days of age. These impairments could be reversed by enhancing sleep. Finally, we find that Spatial Learning requires dopaminergic signaling and that enhancing dopaminergic signaling in aged flies restored learning. Our results are consistent with the impairments seen in rodents and humans. These results thus demonstrate a critical conserved role for sleep in supporting Spatial Learning, and suggest potential avenues for therapeutic intervention during aging.
Topics: Animals; Drosophila; Drosophila melanogaster; Maze Learning; Sleep; Sleep Deprivation; Spatial Learning
PubMed: 32959053
DOI: 10.1093/sleep/zsaa197 -
BMC Evolutionary Biology Nov 2020The Drosophilidae family is traditionally divided into two subfamilies: Drosophilinae and Steganinae. This division is based on morphological characters, and the two...
BACKGROUND
The Drosophilidae family is traditionally divided into two subfamilies: Drosophilinae and Steganinae. This division is based on morphological characters, and the two subfamilies have been treated as monophyletic in most of the literature, but some molecular phylogenies have suggested Steganinae to be paraphyletic. To test the paraphyletic-Steganinae hypothesis, here, we used genomic sequences of eight Drosophilidae (three Steganinae and five Drosophilinae) and two Ephydridae (outgroup) species and inferred the phylogeny for the group based on a dataset of 1,028 orthologous genes present in all species (> 1,000,000 bp). This dataset includes three genera that broke the monophyly of the subfamilies in previous works. To investigate possible biases introduced by small sample sizes and automatic gene annotation, we used the same methods to infer species trees from a set of 10 manually annotated genes that are commonly used in phylogenetics.
RESULTS
Most of the 1,028 gene trees depicted Steganinae as paraphyletic with distinct topologies, but the most common topology depicted it as monophyletic (43.7% of the gene trees). Despite the high levels of gene tree heterogeneity observed, species tree inference in ASTRAL, in PhyloNet, and with the concatenation approach strongly supported the monophyly of both subfamilies for the 1,028-gene dataset. However, when using the concatenation approach to infer a species tree from the smaller set of 10 genes, we recovered Steganinae as a paraphyletic group. The pattern of gene tree heterogeneity was asymmetrical and thus could not be explained solely by incomplete lineage sorting (ILS).
CONCLUSIONS
Steganinae was clearly a monophyletic group in the dataset that we analyzed. In addition to ILS, gene tree discordance was possibly the result of introgression, suggesting complex branching processes during the early evolution of Drosophilidae with short speciation intervals and gene flow. Our study highlights the importance of genomic data in elucidating contentious phylogenetic relationships and suggests that phylogenetic inference for drosophilids based on small molecular datasets should be performed cautiously. Finally, we suggest an approach for the correction and cleaning of BUSCO-derived genomic datasets that will be useful to other researchers planning to use this tool for phylogenomic studies.
Topics: Animals; Drosophilidae; Genetic Speciation; Genomics; Phylogeny
PubMed: 33138771
DOI: 10.1186/s12862-020-01703-7