Search results for "Defence mechanism"
showing 10 items of 34 documents
Allelopathy and the role of allelochemicals in plant defence
2017
International audience; Allelopathy is described as the interference to plant growth resulting from chemical interactions among plants and other organisms mediated through release of plant-produced bioactive secondary metabolites referred to as allelochemicals. A number of mechanisms have been studied for the release of allelochemicals from various plant tissues including volatilization or leaching from aerial parts, exudation from roots and decomposition of plant residues in soil. Despite differences in biological activity and mode of action, related compounds commonly share similar biosynthetic pathways while some classes of metabolites can be produced using diverse biosynthetic pathways.…
Vertebrate defense against parasites: Interactions between avoidance, resistance, and tolerance
2017
Hosts can utilize different types of defense against the effects of parasitism, including avoidance, resistance, and tolerance. Typically, there is tremendous heterogeneity among hosts in these defense mechanisms that may be rooted in the costs associated with defense and lead to trade‐offs with other life‐history traits. Trade‐offs may also exist between the defense mechanisms, but the relationships between avoidance, resistance, and tolerance have rarely been studied. Here, we assessed these three defense traits under common garden conditions in a natural host–parasite system, the trematode eye‐fluke Diplostomum pseudospathaceum and its second intermediate fish host. We looked at host ind…
Plant defense responses induced by arbuscular mycorrhizal fungi
2002
Plants in their environment daily face many organisms such as fungi, bacteria, mycoplasms, viruses, nematodes, etc. Many of them are potential pathogens; in fact thousands of microorganisms are known to cause plant diseases. Despite this large number of deleterious microorganisms, most of the plants are resistant to their attack since they have developed effective mechanisms to protect themselves.
From elicitins to lipid-transfer proteins: a new insight in cell signalling involved in plant defence mechanisms.
2002
Elicitins and lipid-transfer proteins are small cysteine-rich lipid-binding proteins secreted by oomycetes and plant cells, respectively, that share some structural and functional properties. In spite of intensive work on their structure and diversity at the protein and genetic levels, the precise biological roles of lipid-transfer proteins remains unclear, although the most recent data suggest a role in somatic embryogenesis, in the formation of protective surface layers and in defence against pathogens. By contrast, elicitins are known elicitors of plant defence, and recent work demonstrating that elicitins and lipid-transfer proteins share the same biological receptors gives a new perspe…
Differences in Cellular Encapsulation of Six Termite (Isoptera) Species Against Infection by the Entomopathogenic FungusMetarhizium anisopliae
2011
Termites (Isoptera) are eusocial insects, which live in an environment that can favor the spread of pathogens. To reduce the chance of an epizootic within a colony, termites have evolved many defense mechanisms. Most studies have focused on the social aspect of disease resistance, while the individual capacity of a termite to survive an infection remains poorly documented. We previously showed that when the eastern subterranean termite, Reticulitermes flavipes (Kollar), was exposed to the entomopathogenic fungus, Metarhizium anisopliae (Metch.) Sorokin, cellular encapsulation of the penetrating fungus was one of the last lines of defense for individual termites to prevent internal mycosis. …
Ancient Immunity. Phylogenetic Emergence of Recognition-Defense Mechanisms.
2021
Although still scarcely considered by the majority of the biomedical world, invertebrates have greatly contributed to the elucidation of fundamental biological problems [...]
Predictive signs and indicators of aggressiveness and violence: a comparison between a group of adolescents attending an external penal area, a group…
2006
Aim. We considered the spreading and the increasing of aggressive and violent behaviours. The most of them have two common roots: lack of actual motivation and brutality. Our research intends to detect specific indicators and predictive signs of violent and aggressive behaviours. In order to this, scientific literature shows that the most reliable indicators and predictive signs are linked to structural personality features (e.g. defensive strategies, impulse control). Methods. This cross sectional study compares a group of 26 male adolescents with Conduct Disorder (F91.8), a group of 29 male patients with Borderline Personality Disorder (F60.31) and a group of 33 male prisoners with Antiso…
RESISTANCE AND TOLERANCE IN A HOST PLANT–HOLOPARASITIC PLANT INTERACTION: GENETIC VARIATION AND COSTS
2002
Host organisms are believed to evolve defense mechanisms (i.e., resistance and/or tolerance) under selective pressures exerted by natural enemies. A prerequisite for the evolution of resistance and tolerance is the existence of genetic variation in these traits for natural selection to act. However, selection for resistance and/or tolerance may be constrained by negative genetic correlations with other traits that affect host fitness. We studied genetic variation in resistance and tolerance against parasitic infection and the potential fitness costs associated with these traits using a novel study system, namely the interaction between a flowering plant and a parasitic plant. In this system…
Invertebrate lectins: new aspects in retrospects
1991
Invertebrate lectins may be regarded as a special group of lectins, as there are several reasons for this: (a) their role in different defense mechanisms and in nutrition, (b) their specificity, for instance their anti-neuraminyl reactivity (and no mannose-specific lectins) and (c) their distribution in the haemolymph and in organ cells or defense-commited haemocytes.
Defense Responses in Two Ecotypes of Lotus japonicus against Non-Pathogenic Pseudomonas syringae
2013
Lotus japonicus is a model legume broadly used to study many important processes as nitrogen fixing nodule formation and adaptation to salt stress. However, no studies on the defense responses occurring in this species against invading microorganisms have been carried out at the present. Understanding how this model plant protects itself against pathogens will certainly help to develop more tolerant cultivars in economically important Lotus species as well as in other legumes. In order to uncover the most important defense mechanisms activated upon bacterial attack, we explored in this work the main responses occurring in the phenotypically contrasting ecotypes MG-20 and Gifu B-129 of L. ja…