Search results for "Olfactory"

Olfactory response of two aphid parasitoids, Lysiphlebus testaceipes and Aphidius colemani, to aphid-infested plants from a distance

2004

The role of volatile stimuli in the host-searching behaviour of the two parasitoid species Lysiphlebus testaceipes Cresson and Aphidius colemani Viereck (Hymenoptera: Braconidae) was studied in relation to the host Aphis gossypii Glover (Homoptera: Aphididae) on cucumber plants, Cucumis sativa L. (Cucurbitaceae). Experiments were carried out in the laboratory in a wind tunnel, exposing individual parasitoids to signals from three sources simultaneously: (1) a complex of cucumber plants, Cucumis sativa , and A. gossypii ; (2) uninfested cucumber plants; and (3) dummy cardboard plants. The flight response of the female parasitoids was considered oriented when they landed on plants and non-ori…

How Do Infanticidal Male Bank Voles (Myodes glareolus) Find the Nest with Pups?

2016

Infanticide, the killing of conspecific young, occurs in most mammal species, like in our study species, the bank vole (Myodes glareolus). Infanticide by adult males is regarded as a strong factor affecting recruitment of young into population. It is considered as an adaptive behaviour, which may increase male fitness via resource gain or an increased access to mates. When an intruder is approaching the nest, the mother should not be present, as her nest guarding is very aggressive and successful. Pups use ultrasonic vocalisation to call their mother when mother leaves nest for foraging but it is not know which cues do infanticidal males use to find the nest with vulnerable pups to commit i…

Coupling transcriptomics and behaviour to unveil the olfactory system of Spodoptera exigua larvae

2020

AbstractChemoreception in insects is crucial for many aspects related to food seeking, enemy avoidance, and reproduction. Different families of receptors and binding proteins interact with chemical stimuli, including odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant binding proteins (OBPs) and chemosensory proteins (CSPs). In this work, we describe the chemosensory-related gene repertoire of the worldwide spread pest Spodoptera exigua (Lepidoptera: Noctuide) focusing on the transcripts expressed in larvae, which feed on many horticultural crops producing yield losses. A comprehensive de novo assembly that includes reads from chemosensory organs of larva…

A manipulative parasite increasing an antipredator response decreases its vulnerability to a nonhost predator.

2009

8 pages; International audience; Trophically transmitted parasites have to deal with the antipredator adaptations of their intermediate hosts. Some of these parasites induce behavioural changes in their intermediate hosts that make them more vulnerable to predation by definitive hosts. However, the adaptiveness of behavioural manipulation also depends on the probability of being eaten by a nonhost predator. Parasites might therefore try to use specific antipredator responses of intermediate hosts to avoid this dead end. We tested this hypothesis using the acanthocephalan Polymorphus minutus and its intermediate amphipod host, Gammarus roeseli. In their natural habitat, uninfected G. roeseli…

Prox1 Is Required for Oligodendrocyte Cell Identity in Adult Neural Stem Cells of the Subventricular Zone

2016

Abstract Adult neural stem cells with the ability to generate neurons and glia cells are active throughout life in both the dentate gyrus (DG) and the subventricular zone (SVZ). Differentiation of adult neural stem cells is induced by cell fate determinants like the transcription factor Prox1. Evidence has been provided for a function of Prox1 as an inducer of neuronal differentiation within the DG. We now show that within the SVZ Prox1 induces differentiation into oligodendrocytes. Moreover, we find that loss of Prox1 expression in vivo reduces cell migration into the corpus callosum, where the few Prox1 deficient SVZ-derived remaining cells fail to differentiate into oligodendrocytes. Thu…

Drosophila Full-Length Amyloid Precursor Protein is Required for Visual Working Memory and Prevents Age-Related Memory Impairment

2018

Summary The β-amyloid precursor protein (APP) plays a central role in the etiology of Alzheimer's disease (AD). However, its normal physiological functions are still unclear. APP is cleaved by various secretases whereby sequential processing by the β- and γ-secretases produces the β-amyloid peptide that is accumulating in plaques that typify AD. In addition, this produces secreted N-terminal sAPPβ fragments and the APP intracellular domain (AICD). Alternative cleavage by α-secretase results in slightly longer secreted sAPPα fragments and the identical AICD. Whereas the AICD has been connected with transcriptional regulation, sAPPα fragments have been suggested to have a neurotrophic and neu…

Clearing Amyloid-β through PPARγ/ApoE Activation by Genistein is a Treatment of Experimental Alzheimer’s Disease

2016

Amyloid-b (Ab) clearance from brain, which is decreased in Alzheimer's disease, is facilitated by apolipoprotein E (ApoE). ApoE is upregulated by activation of the retinoid X receptor moiety of the RXR/PPAR dimeric receptor. As we have previously demonstrated, estrogenic compounds, such as genistein, have antioxidant activity, which can be evidenced by increased expression of manganese superoxide dismutase (MnSOD). Furthermore, genistein is a non-toxic, well-tested, and inexpensive drug that activates PPARg receptor. We isolated and cultured cortical astrocytes from dissected cerebral cortices of neonatal mice (C57BL/6 J). Preincubation with genistein (5 mM) for 24 hours, prior to the addit…

Biophysical and functional characterization of the human olfactory receptor OR1A1 expressed in a mammalian inducible cell line

2014

International audience; Olfactory receptors (ORs) play a crucial role in detecting the odorant molecules present in the surrounding environment. These receptors, which belong to class A G-protein-coupled receptors, constitute the largest transmembrane protein family in the human genome. Functional studies showed that the OR family includes members that are able to respond to a large set of odorants and members that are activated by a relatively small number of related odorants. To understand the molecular mechanisms that govern the receptor-ligand interactions, we overexpressed the human OR hOR1A1 in a stable tetracycline-inducible HEK293S cell line. This receptor was engineered by insertin…

2016

Cytoglobin (Cygb) is a vertebrate globin with so far poorly defined function. It is expressed in the fibroblast cell-lineage but has also been found in neurons. Here we provide, using immunohistochemistry, a detailed study on the distribution of Cygb in the mouse brain. While Cygb is a cytoplasmic protein in active cells of the supportive tissue, in neurons it is located in the cytoplasm and the nucleus. We found the expression of Cygb in all brain regions, although only a fraction of the neurons was Cygb-positive. Signals were of different intensity ranging from faint to very intense. Telencephalic neurons in all laminae of the cerebral cortex, in the olfactory bulb (in particular periglom…

Spontaneous brain processing of the mammary pheromone in rabbit neonates prior to milk intake.

2016

International audience; Chemical signals play a critical role in interindividual communication, including mother-young relationships. Detecting odor cues released by the mammary area is vital to the newborn's survival. European rabbit females secret a mammary pheromone (MP) in their milk, which releases sucking related orocephalic movements in newborns. Pups spontaneously display these typical movements at birth, independently of any perinatal learning. Our previous Fos mapping study (Charra et al., 2012) performed in 4-day-old rabbits showed that the MP activated a network of brain regions involved in osmoregulation, odor processing and arousal in comparison with a control odor. However, a…