Search results for "SIGNALLING"
showing 10 items of 249 documents
Investment in multiple defences protects a nematode-bacterium symbiosis from predation
2017
The act of predation often comprises multiple sequential steps whereby prey can employ defences at all or some of these stages to deter predation. However, investment in defences is costly unless they are outweighed by conferring some benefit to the bearer. One system that employs multiple defences is that of the entomopathogenic nematode Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus luminescens. This nematodeebacterium complex infects and kills soil-dwelling insect larvae, in which they then reproduce and juveniles emerge 2 weeks later. Predation of the infected host cadaver at any point during infection is fatal for the parasitic colony inside. Infected individual…
The macroecology of chemical communication in lizards: do climatic factors drive the evolution of signalling glands?
2018
Chemical communication plays a pivotal role in shaping sexual and ecological interactions among animals. In lizards, fundamental mechanisms of sexual selection such as female mate choice have rarely been shown to be influenced by quantitative phenotypic traits (e.g., ornaments), while chemical signals have been found to potentially influence multiple forms of sexual and social interactions, including mate choice and territoriality. Chemical signals in lizards are secreted by glands primarily located on the edge of the cloacae (precloacal glands, PG) and thighs (femoral glands), and whose interspecific and interclade number ranges from 0 to > 100. However, elucidating the factors underlying …
NO Signalling in Plant Immunity
2016
The importance of nitric oxide (NO) in innate and adaptive immunity in mammals is well recognised. NO exerts antimicrobial properties against invaders but also displays immunoregulatory functions in which S-nitrosylation represents a signalling process of major importance. Over the last two decades, a growing body of evidence suggests that NO is also a major component of plant immunity. Our understanding of its role in plant defence has been enriched by the identification and functional analysis of S-nitrosylated proteins. The recent identification of new S-nitrosylated proteins including the chaperone-like enzyme cell division cycle 48 (CDC48), histone deacetylases (HDACs) and calmodulin (…
Intracellular compartmentation and plant cell signalling
1997
Compartmentation is an essential feature of eukaryotic cells, and is crucial for the regulation of cell metabolism. Recent progress has significantly improved the understanding of signal transduction pathways in plants, including the activation of light-signalling networks and the tightly controlled generation of the calcium message. Cell compartmentation is important for the regulation and proliferation of these signalling processes.
‘Communication breakdown’: the evolution of signal unreliability and deception
2014
For a signalling system to be stable, signals must confer net fitness benefits to senders and receivers, which means that some aspect of their design must correlate with a quality that receivers benefit from knowing about. However, examples abound where this correlation is complicated by phenomena commonly referred to as deception and/or signal unreliability. We argue here that unreliability and deception are notions marred with conceptual ambiguities, often used as equivalent or as catch-all terms for qualitatively different processes. Signal unreliability refers to a pattern of design–information dissociation that can arise through different processes, some deceptive and some not, with di…
Energetic costs of size and sexual signalling in a wolf spider
1998
A prerequisite for honest handicaps is that there are significant condition–dependent costs in the expression of sexual traits. In the wolf spider Hygrolycosa rubrofasciata (Ohlert), sexual signalling (drumming) is costly in terms of increased mortality. Here we investigated whether this mortality may be caused by increased energy expenditure. During sexual signalling, metabolic rate was 22 times higher than at rest and four times higher than when males were actively moving. Metabolic rate per unit mass was positively related to absolute body mass during sexual signalling but not during other activities. This positive relationship is novel to any studies of metabolic rates. Indeed, it seems…
Type-2 histone deacetylases as new regulators of elicitor-induced cell death in plants
2011
voir Addenda, notes additionnelles complétant l'article : "Dahan, J., Hammoudi, V., Wendehenne, D., Bourque, S. (2011). Type 2 histone deacetylases play a major role in the control of elicitor-induced cell death in tobacco. Plant signaling & behavior, 6 (11), 1865-1867. DOI : 10.4161/psb.6.11.17848".; International audience; Plant resistance to pathogen attack is often associated with a localized programmed cell death called hypersensitive response (HR). How this cell death is controlled remains largely unknown. Upon treatment with cryptogein, an elicitor of tobacco defence and cell death, we identified NtHD2a and NtHD2b, two redundant isoforms of type-2 nuclear histone deacetylases (HDACs…
Arabidopsis plants deficient in plastidial glyceraldehyde-3-phosphate dehydrogenase show alterations in abscisic acid (ABA) signal transduction: inte…
2010
Abscisic acid (ABA) controls plant development and regulates plant responses to environmental stresses. A role for ABA in sugar regulation of plant development has also been well documented although the molecular mechanisms connecting the hormone with sugar signal transduction pathways are not well understood. In this work it is shown that Arabidopsis thaliana mutants deficient in plastidial glycolytic glyceraldehyde-3-phosphate dehydrogenase (gapcp1gapcp2) are ABA insensitive in growth, stomatal closure, and germination assays. The ABA levels of gapcp1gapcp2 were normal, suggesting that the ABA signal transduction pathway is impaired in the mutants. ABA modified gapcp1gapcp2 gene expressio…
Regulation of reactive oxygen species production by a 14-3-3 protein in elicited tobacco cells.
2007
International audience; The regulation of the system responsible for the production of reactive oxygen species (ROS) during plant–microorganism interaction is still largely unknown. The protein NtrbohD has been recently demonstrated as the plasma membrane oxidase responsible for ROS production in elicited tobacco cells. Here, its C-terminus part was used as a bait in a two-hybrid screen in order to identify putative regulators of this system. This led to the isolation of a cDNA coding for a member of the 14-3-3 protein family. The corresponding transcript was induced after infiltration of tobacco leaves with the fungal elicitor cryptogein. Tobacco cells transformed with an antisense constru…
Nitric oxide signalling in plants: interplays with Ca2+ and protein kinase
2008
International audience; Much attention has been paid to nitric oxide (NO)research since its discovery as a physiological mediator of plant defence responses. In recent years, newer roles have been attributed to NO, ranging from root development to stomatal closure. The molecular mechanisms underlying NO action in plants are just begun to emerge. The currently available data illustrate that NO can directly influence the activity of target proteins through nitrosylation and has the capacity to act as a Ca2+-mobilizing intracellular messenger. The interplay between NO and Ca2+ has important functional implications, expanding and enriching the possibilities for modulating transduction processes…