Peptidoglycan sensing by octopaminergic neurons modulates Drosophila oviposition

Abstract

As infectious diseases pose a threat to host integrity, eukaryotes have evolved mechanisms to eliminate pathogens. In addition to develop strategies reducing infection, animals can engage in behaviors that lower the impact of the infection. The molecular mechanisms by which microbes impact host behavior are not well understood. We demonstrate that bacterial infection of Drosophila females reduces oviposition and that peptidoglycan, the component that activates Drosophila antibacterial response, is also the elicitor of this behavioral change. We show that peptidoglycan regulates egg-laying rate by activating NF-κB signaling pathway in octopaminergic neurons and that, a dedicated peptidoglycan degrading enzyme acts in these neurons to buffer this behavioral response. This study shows that a unique ligand and signaling cascade are used in immune cells to mount an immune response and in neurons to control fly behavior following infection. This may represent a case of behavioral immunity.DOI: http://dx.doi.org/10.7554/eLife.21937.001

Navigating infection risk during oviposition and larval foraging in a holometabolous insect

“…It is unclear which cues of DCV are detected by females, whether they are 324 detecting the virus directly, or cues of virus derived pathology in the fly carcass. Similar 325 avoidance of pathogenic bacteria has been described in both D. melanogaster[6,8,10] and C. 326 elegans[49,50]. Avoidance of virus infection has also been described in a range of 327…”

“…The behavioural immune system, the suite of behaviours that allow animals to avoid contact 34 with infectious environments or conspecifics, is the first line of defence against infection [1-35 3]. Avoidance of infection relies on detecting cues of parasite presence -such as visual cues of 36 infection risk or secondary pathogen metabolites -and integrating this sensory information to 37 avoid sources of infection [4][5][6][7][8][9][10]. In addition to external cues of infection risk, the internal 38 state of the animal, including its physiological status as a result of prior pathogen exposure, 39 may also affect the ability to detect and avoid infection [11][12][13].…”

“…The environment in which adult insects choose to oviposit 61 is therefore a major determinant both of offspring environmental quality and infection risk 62 [7,16,20]. Infection avoidance by insects during oviposition has been observed in response to 63 a number of parasites and appears to be driven by diverse sensory cues, including avoidance 64 of parasitoid wasp visual cues [7], and olfactory detection of bacteria and fungi [6,10]. 65…”

“…invertebrates, such as gypsy moth larvae that avoid eating leaves contaminated with virus [51] and lobsters that avoid virus-infected conspecifics [52]. This avoidance likely relies on 329 dedicated chemosensory pathways for olfactory cues [6,9,10,49]. 330…”

Rab converter DMon1 constitutes a novel node in the brain-gonad axis essential for female germline maturation

“…Since c155-GAL4 is a pan-neuronal driver, we wanted to determine if Dmon1 is required in a subset of neurons. The appropriate candidate in this regard are the octopamiergic/tyraminergic neurons (OPNs) as the ovarian peritoneal sheath muscles are innervated by this class of neurons and there is no direct innervation to the ovary (25)(26)(27). We thus tested if knock down of Dmon1 in OPNs alone, can influence ovarian growth and maturation.…”