Drosophila innate immunity and response to fungal infections

Department of Biology, Stanford University, Stanford, CA 94305-5020, USA.
Cellular Microbiology (Impact Factor: 4.92). 06/2008; 10(5):1021-6. DOI: 10.1111/j.1462-5822.2008.01120.x
Source: PubMed


The fruit fly Drosophila melanogaster is an important model for the analysis of the interaction between host immune systems and fungal pathogens. Recent experiments have extended our understanding of the Toll-based signalling pathway critical to response to fungal infections, and identified new elements involved in cellular and humoral-based defences. The fly immune system shows remarkable sophistication in its ability to discriminate among pathogens, and the powerful genetics available to researchers studying the adult fly response, and the ability to manipulate cultured phagocytic cell lines with RNAi, are allowing researchers to dissect the molecular details of the process.

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Available from: Malcolm Whiteway, Oct 13, 2014
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    • "identity) of yeast PMT4 O-mannosyltransferase involved in protein O-mannosylation/glycosylation and determining the structure and integrity of fungal cell walls (Lengeler et al., 2008). It is well-known that fungal cell wall components (mainly the glucans) are the primary pathogenassociated molecular patterns that trigger insect Toll pathway to induce immune responses (Gottar et al., 2006; Levitin and Whiteway, 2008).Thus, upregulation of these genes, if not all, in ΔMrpacC could lead to mutant cell wall remodelling that in turn would trigger stronger insect immune responses. Thus, it could be concluded that MrpacC contributes to fungal virulence by maintaining cell wall integrity/remodelling in insect haemocoels. "
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    ABSTRACT: pH-responsive transcription factor of the PacC/Rim101 family governs adaptation to environment, development and virulence in many fungal pathogens. In this study, we report the functions of a PacC homolog, MrpacC, in an insect pathogenic fungus Metarhizium robertsii. The gene was highly transcribed in the fungus in alkaline conditions and deletion of MrpacC impaired fungal responses to ambient pH and salt/metal challenges but not osmotic stress. We found that MrpacC is required for fungal full virulence by contributing to penetration of insect cuticles, mycosis of insect cadavers and evasion of host immunity. In MrpacC deletion strains, the chitinase but not protease activity was reduced, which was consistent with the down-regulation of Groups A and C chitinase genes. Further, the glucosyltransferase genes involved in cell wall remodeling and protein glycosylation were up-regulated in ΔMrpacC. MrpacC transcriptional control of chitinase and glucosyltransferase genes was verified both by the presence of PacC consensus binding motif in gene promoter regions and the promoter DNA binding assays. The results of this study not only advances the understanding of PacC function in fungal development and virulence but will also facilitate future studies on the mechanism(s) behind the selective control of target genes by PacC.
    Environmental Microbiology 04/2015; 17(4):994-1008. DOI:10.1111/1462-2920.12451 · 6.20 Impact Factor
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    • "There have been many reports on AMPs from various insect species, but very few reviews on insect AMPs (Imler and Bulet 2005; Li et al. 2006). Several reviews related to insect AMPs are mainly from Drosophila with a focus on activation of AMPs in response to various infections or regulation of AMP gene expressions by the Toll and IMD signaling pathways (Fullaondo and Lee 2012; Hetru and Hoffmann 2009; Lazzaro 2008; Lemaitre and Hoffmann 2007; Levitin and Whiteway 2008; Moy and Cherry 2013). Antiparasitic peptides and antimalarial peptides have been reviewed recently (Bell 2011; Pretzel et al. 2013). "
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    ABSTRACT: Insects are one of the major sources of antimicrobial peptides/proteins (AMPs). Since observation of antimicrobial activity in the hemolymph of pupae from the giant silk moths Samia Cynthia and Hyalophora cecropia in 1974 and purification of first insect AMP (cecropin) from H. cecropia pupae in 1980, over 150 insect AMPs have been purified or identified. Most insect AMPs are small and cationic, and they show activities against bacteria and/or fungi, as well as some parasites and viruses. Insect AMPs can be classified into four families based on their structures or unique sequences: the α-helical peptides (cecropin and moricin), cysteine-rich peptides (insect defensin and drosomycin), proline-rich peptides (apidaecin, drosocin, and lebocin), and glycine-rich peptides/proteins (attacin and gloverin). Among insect AMPs, defensins, cecropins, proline-rich peptides, and attacins are common, while gloverins and moricins have been identified only in Lepidoptera. Most active AMPs are small peptides of 20-50 residues, which are generated from larger inactive precursor proteins or pro-proteins, but gloverins (~14 kDa) and attacins (~20 kDa) are large antimicrobial proteins. In this mini-review, we will discuss current knowledge and recent progress in several classes of insect AMPs, including insect defensins, cecropins, attacins, lebocins and other proline-rich peptides, gloverins, and moricins, with a focus on structural-functional relationships and their potential applications.
    Applied Microbiology and Biotechnology 05/2014; 98(13). DOI:10.1007/s00253-014-5792-6 · 3.34 Impact Factor
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    • "El sistema celular, por su parte, está compuesto por los hemocitos que circulan por el hemocele capaces de reconocer los elementos extraños mediante receptores tipo Toll que activan la producción de varios péptidos antimicrobianos (Levitin y Whiteway, 2008). Cuando la concentración de microorganismos patógenos es baja, la fagocitosis es el principal mecanismo para eliminar a los invasores. "
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    ABSTRACT: The study of the entomopathogenic fungi-insect interaction has been important development of strategies for controlling crop pests of agricultural importance. Each one of the organisms has evolved attack and defense mechanisms for their survival. This paper is a detailed description of the fungal attack systems and the defense mechanisms of the insects. Knowledge of these processes can help for the isolation, selection and improvement of fungal strains to be used as biological control agents and assist protection strategies for beneficial species.
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