« Previous Abstract"Effect of juvenoids on predator-induced polyphenism in the water flea, Daphnia pulex"    Next AbstractMating pheromone-induced alteration of cell surface proteins in the heterobasidiomycetous yeast Tremella mesenterica »

PLoS One

Title:		Ionotropic glutamate receptors mediate inducible defense in the water flea Daphnia pulex
Author(s):		Miyakawa H; Sato M; Colbourne JK; Iguchi T;
Address:		"National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan; Okazaki Institute for Integrative Bioscience, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan. National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan; Okazaki Institute for Integrative Bioscience, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan; Department of Basic Biology, Faculty of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, Japan. School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom"
Journal Title:		PLoS One
Year:		2015
Volume:		20150323
Issue:		3
Page Number:		e0121324 -
DOI:		10.1371/journal.pone.0121324
ISSN/ISBN:		1932-6203 (Electronic) 1932-6203 (Linking)
Abstract:		"Phenotypic plasticity is the ability held in many organisms to produce different phenotypes with a given genome in response to environmental stimuli, such as temperature, nutrition and various biological interactions. It seems likely that environmental signals induce a variety of mechanistic responses that influence ontogenetic processes. Inducible defenses, in which prey animals alter their morphology, behavior and/or other traits to help protect against direct or latent predation threats, are among the most striking examples of phenotypic plasticity. The freshwater microcrustacean Daphnia pulex forms tooth-like defensive structures, 'neckteeth,' in response to chemical cues or signals, referred to as 'kairomones,' in this case released from phantom midge larvae, a predator of D. pulex. To identify factors involved in the reception and/or transmission of a kairomone, we used microarray analysis to identify genes up-regulated following a short period of exposure to the midge kairomone. In addition to identifying differentially expressed genes of unknown function, we also found significant up-regulation of genes encoding ionotropic glutamate receptors, which are known to be involved in neurotransmission in many animal species. Specific antagonists of these receptors strongly inhibit the formation of neckteeth in D. pulex, although agonists did not induce neckteeth by themselves, indicating that ionotropic glutamate receptors are necessary but not sufficient for early steps of neckteeth formation in D. pulex. Moreover, using co-exposure of D. pulex to antagonists and juvenile hormone (JH), which physiologically mediates neckteeth formation, we found evidence suggesting that the inhibitory effect of antagonists is not due to direct inhibition of JH synthesis/secretion. Our findings not only provide a candidate molecule required for the inducible defense response in D. pulex, but also will contribute to the understanding of complex mechanisms underlying the recognition of environmental changes, which form the basis of phenotypic plasticity"
Keywords:		"Animals Daphnia/*metabolism/physiology Phenotype Pheromones/metabolism Receptors, Ionotropic Glutamate/genetics/*metabolism;"
Notes:		"MedlineMiyakawa, Hitoshi Sato, Masanao Colbourne, John K Iguchi, Taisen eng Research Support, Non-U.S. Gov't 2015/03/24 PLoS One. 2015 Mar 23; 10(3):e0121324. doi: 10.1371/journal.pone.0121324. eCollection 2015"