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Genetics Oct 2018The gastrointestinal tract has recently come to the forefront of multiple research fields. It is now recognized as a major source of signals modulating food intake,... (Review)
Review
The gastrointestinal tract has recently come to the forefront of multiple research fields. It is now recognized as a major source of signals modulating food intake, insulin secretion and energy balance. It is also a key player in immunity and, through its interaction with microbiota, can shape our physiology and behavior in complex and sometimes unexpected ways. The insect intestine had remained, by comparison, relatively unexplored until the identification of adult somatic stem cells in the intestine over a decade ago. Since then, a growing scientific community has exploited the genetic amenability of this insect organ in powerful and creative ways. By doing so, we have shed light on a broad range of biological questions revolving around stem cells and their niches, interorgan signaling and immunity. Despite their relatively recent discovery, some of the mechanisms active in the intestine of flies have already been shown to be more widely applicable to other gastrointestinal systems, and may therefore become relevant in the context of human pathologies such as gastrointestinal cancers, aging, or obesity. This review summarizes our current knowledge of both the formation and function of the digestive tract, with a major focus on its main digestive/absorptive portion: the strikingly adaptable adult midgut.
Topics: Animals; Drosophila melanogaster; Gastrointestinal Tract; Morphogenesis
PubMed: 30287514
DOI: 10.1534/genetics.118.300224 -
Frontiers in Immunology 2022The innate immune response provides the first line of defense against invading pathogens, and immune disorders cause a variety of diseases. The fruit fly employs... (Review)
Review
The innate immune response provides the first line of defense against invading pathogens, and immune disorders cause a variety of diseases. The fruit fly employs multiple innate immune reactions to resist infection. First, epithelial tissues function as physical barriers to prevent pathogen invasion. In addition, macrophage-like plasmatocytes eliminate intruders through phagocytosis, and lamellocytes encapsulate large particles, such as wasp eggs, that cannot be phagocytosed. Regarding humoral immune responses, the fat body, equivalent to the mammalian liver, secretes antimicrobial peptides into hemolymph, killing bacteria and fungi. has been shown to be a powerful model for studying the mechanism of innate immunity and host-pathogen interactions because and higher organisms share conserved signaling pathways and factors. Moreover, the ease with which genetic and physiological characteristics can be manipulated prevents interference by adaptive immunity. In this review, we discuss the signaling pathways activated in innate immunity, namely, the Toll, Imd, JNK, JAK/STAT pathways, and other factors, as well as relevant regulatory networks. We also review the mechanisms by which different tissues, including hemocytes, the fat body, the lymph gland, muscles, the gut and the brain coordinate innate immune responses. Furthermore, the latest studies in this field are outlined in this review. In summary, understanding the mechanism underlying innate immunity orchestration in will help us better study human innate immunity-related diseases.
Topics: Animals; Drosophila; Drosophila melanogaster; Hemocytes; Humans; Immunity, Innate; Mammals; Signal Transduction
PubMed: 35911716
DOI: 10.3389/fimmu.2022.905370 -
ELife Oct 2023Individual species of bacteria and yeast present in the food of wild fruit flies work together to provide the nutrients needed for larval growth.
Individual species of bacteria and yeast present in the food of wild fruit flies work together to provide the nutrients needed for larval growth.
Topics: Animals; Drosophila melanogaster; Microbiota; Drosophila; Nutrients
PubMed: 37819270
DOI: 10.7554/eLife.92482 -
ELife Sep 2023Experiments on female fruit flies reveal more about the molecular mechanisms involved as germline stem cells transition to become egg cells.
Experiments on female fruit flies reveal more about the molecular mechanisms involved as germline stem cells transition to become egg cells.
Topics: Animals; Female; Drosophila melanogaster; Drosophila Proteins; Drosophila; Germ Cells; Stem Cells
PubMed: 37772961
DOI: 10.7554/eLife.91998 -
Cells Feb 2023Cancer metastasis, the process by which tumour cells spread throughout the body and form secondary tumours at distant sites, is the leading cause of cancer-related... (Review)
Review
Cancer metastasis, the process by which tumour cells spread throughout the body and form secondary tumours at distant sites, is the leading cause of cancer-related deaths. The metastatic cascade is a highly complex process encompassing initial dissemination from the primary tumour, travel through the blood stream or lymphatic system, and the colonisation of distant organs. However, the factors enabling cells to survive this stressful process and adapt to new microenvironments are not fully characterised. Drosophila have proven a powerful system in which to study this process, despite important caveats such as their open circulatory system and lack of adaptive immune system. Historically, larvae have been used to model cancer due to the presence of pools of proliferating cells in which tumours can be induced, and transplanting these larval tumours into adult hosts has enabled tumour growth to be monitored over longer periods. More recently, thanks largely to the discovery that there are stem cells in the adult midgut, adult models have been developed. We focus this review on the development of different Drosophila models of metastasis and how they have contributed to our understanding of important factors determining metastatic potential, including signalling pathways, the immune system and the microenvironment.
Topics: Animals; Drosophila melanogaster; Neoplasms; Stem Cells; Signal Transduction; Drosophila; Tumor Microenvironment
PubMed: 36899813
DOI: 10.3390/cells12050677 -
ELife May 2020The origins of the posterior lobe, a recently evolved structure in some species of , have become clearer.
The origins of the posterior lobe, a recently evolved structure in some species of , have become clearer.
Topics: Animals; Biological Evolution; Drosophila; Drosophila melanogaster; Extracellular Matrix
PubMed: 32463359
DOI: 10.7554/eLife.57668 -
Immunological Reviews Oct 2023The clearance of dead and dying cells, termed efferocytosis, is a rapid and efficient process and one that is critical for organismal health. The extraordinary speed and... (Review)
Review
The clearance of dead and dying cells, termed efferocytosis, is a rapid and efficient process and one that is critical for organismal health. The extraordinary speed and efficiency with which dead cells are detected and engulfed by immune cells within tissues presents a challenge to researchers who wish to unravel this fascinating process, since these fleeting moments of uptake are almost impossible to catch in vivo. In recent years, the fruit fly (Drosophila melanogaster) embryo has emerged as a powerful model to circumvent this problem. With its abundance of dying cells, specialist phagocytes and relative ease of live imaging, the humble fly embryo provides a unique opportunity to catch and study the moment of cell engulfment in real-time within a living animal. In this review, we explore the recent advances that have come from studies in the fly, and how live imaging and genetics have revealed a previously unappreciated level of diversity in the efferocytic program. A variety of efferocytic strategies across the phagocytic cell population ensure efficient and rapid clearance of corpses wherever death is encountered within the varied and complex setting of a multicellular living organism.
Topics: Animals; Humans; Drosophila melanogaster; Apoptosis; Phagocytosis; Phagocytes; Drosophila
PubMed: 37589239
DOI: 10.1111/imr.13266 -
Cell Reports Jul 2023Sensitivity to numbers is a crucial cognitive ability. The lack of experimental models amenable to systematic genetic and neural manipulation has precluded discovering...
Sensitivity to numbers is a crucial cognitive ability. The lack of experimental models amenable to systematic genetic and neural manipulation has precluded discovering neural circuits required for numerical cognition. Here, we demonstrate that Drosophila flies spontaneously prefer sets containing larger numbers of objects. This preference is determined by the ratio between the two numerical quantities tested, a characteristic signature of numerical cognition across species. Individual flies maintained their numerical choice over consecutive days. Using a numerical visual conditioning paradigm, we found that flies are capable of associating sucrose with numerical quantities and can be trained to reverse their spontaneous preference for large quantities. Finally, we show that silencing lobula columnar neurons (LC11) reduces the preference for more objects, thus identifying a neuronal substrate for numerical cognition in invertebrates. This discovery paves the way for the systematic analysis of the behavioral and neural mechanisms underlying the evolutionary conserved sensitivity to numerosity.
Topics: Animals; Drosophila melanogaster; Cognition; Drosophila; Neurons
PubMed: 37453418
DOI: 10.1016/j.celrep.2023.112772 -
Journal of Insect Science (Online) May 2018Lek mating systems are relatively rare but occur in a diverse taxonomic array of animals, including birds, mammals, anurans, and insects. Such systems exhibit four... (Review)
Review
Lek mating systems are relatively rare but occur in a diverse taxonomic array of animals, including birds, mammals, anurans, and insects. Such systems exhibit four features: 1) males provide no parental care and supply only gametes; 2) males are spatially aggregated at mating arenas (or leks); 3) males do not control access to resources critical to females; and 4) females are free to select mates at the arena. Among insects, fruit flies of the families Tephritidae and Drosophilidae display lek behavior that closely resembles the 'classic' lek mating systems of vertebrate species. The objective of this paper is to provide an overview of empirical findings on lek-forming tephritid and drosophilid flies. The essay is organized around a series of 19 questions, the first six of which provide background information on fruit fly leks. These questions deal with the location, persistence, and size of leks as well as pheromonal attraction of females and the nature of male-male aggression. The remaining questions touch on broader issues that are common to the study of lekking species regardless of taxonomic affiliation. For example, these questions concern skewed mating distributions among males, male signals important in female choice, the importance of male aggression and signaling position in affecting male mating success, the possibility of male choice, costs to males associated with lek displays, and evidence of direct and indirect benefits to females resulting from mate selection etc. Reflecting data availability, emphasis is on precopulatory mate choice, sperm competition and female cryptic choice are briefly addressed.
Topics: Animals; Drosophilidae; Female; Male; Sexual Behavior, Animal; Tephritidae
PubMed: 29850851
DOI: 10.1093/jisesa/iey048 -
The European Journal of Neuroscience Jan 2020A key feature of circadian rhythms is the sleep/wake cycle. Sleep causes reduced responsiveness to the environment, which puts animals in a particularly vulnerable... (Review)
Review
A key feature of circadian rhythms is the sleep/wake cycle. Sleep causes reduced responsiveness to the environment, which puts animals in a particularly vulnerable state; yet sleep has been conserved throughout evolution, indicating that it fulfils a vital purpose. A core function of sleep across species has not been identified, but substantial advances in sleep research have been made in recent years using the genetically tractable model organism, Drosophila melanogaster. This review describes the universality of sleep, the regulation of sleep, and current theories on the function of sleep, highlighting a historical and often overlooked theory called the Free Radical Flux Theory of Sleep. Additionally, we summarize our recent work with short-sleeping Drosophila mutants and other genetic and pharmacological tools for manipulating sleep which supports an antioxidant theory of sleep and demonstrates a bi-directional relationship between sleep and oxidative stress.
Topics: Animals; Circadian Rhythm; Drosophila; Drosophila Proteins; Drosophila melanogaster; Sleep
PubMed: 30295966
DOI: 10.1111/ejn.14197