Search results for "MAC"
showing 10 items of 24950 documents
Automatic measurement of wood fiber orientation and knot detection using an optical system based on heating conduction.
2015
In this paper, a new approach to computing the deviation of wood grain is proposed. To do this, the thermal conduction properties of timber are used (higher conduction in the fiber direction). Exciting the surface of the wood with a laser and capturing the thermal conduction using a thermal camera, an ellipse can be observed. Using a method similar to the tracheid effect, it is possible to extract information from this ellipse, such as the slope of grain and the presence of knots. With this method it is therefore possible to extend the mechanical model (assessing the mechanical properties of timber) to take certain singularities into account. Using this approach, the slope of grain can be e…
Ecdysone and ecdysterone in physogastric termite queens and eggs of Macrotermes bellicosus and Macrotermes subhyalinus
1978
Abstract Physogastric queens and freshly laid eggs of two species of termites ( Macrotermes bellicosus and Macrotermes subhyalinus ) are found to contain high levels of ecdysteroids (molting hormones) as indicated by radioimmunoassay and Musca bioassay. Ecdysteroids are accumulated in the ovaries of the queen and then stored in the eggs since newly laid eggs contain ecdysteroid concentrations similar to those found in the ovaries. Gas chromatography-mass spectrometry demonstrates that ecdysone (α-ecdysone) as well as ecdysterone (β-ecdysone) are present in queen ovaries and in eggs and that ecdysone is quantitatively the more important ecdysteroid in both ovary and eggs.
Synthesis and properties of a photoaffinity labeling reagent for protoporphyrinogen oxidases, the target enzymes of diphenyl ether herbicides
1994
A diazoketone 3 has been synthesized in two steps from acifluorfen 1, a diphenyl ether herbicide. Like the parent compound 1, the diazoketone 3 is toxic to plant cells and inhibits protoporphyrinogen oxidase, the molecular target of diphenyl ether herbicides. On photolysis of 3 in methanol, the generated carbene mainly undergoes the Wolff rearrangement to a ketene which further adds methanol, but many other products are observed. A tritiated derivative of 3 has been prepared which is suitable for photoaffinity labeling experiments.
Bacterial rhamnolipids are novel MAMPs conferring resistance to Botrytis cinerea in grapevine
2009
International audience; Rhamnolipids produced by the bacteria Pseudomonas aeruginosa are known as very efficient biosurfactant molecules. They are used for a wide range of industrial applications, especially in food, cosmetics and pharmaceutical formulations as well as in bioremediation of pollutants. In this paper, the role of rhamnolipids as novel molecules triggering defence responses and protection against the fungus Botrytis cinerea in grapevine is presented. The effect of rhamnolipids was assessed in grapevine using cell suspension cultures and vitro-plantlets. Ca2+ influx, mitogen-activated protein kinase activation and reactive oxygen species production form part of early signalling…
Inhibitory Effect of Azamacrocyclic Ligands on Polyphenol Oxidase in Model and Food Systems
2020
[EN] Enzymatic browning is one of the main problems faced by the food industry due to the enzyme polyphenol oxidase (PPO) provoking an undesirable color change in the presence of oxygen. Here, we report the evaluation of 10 different azamacrocyclic compounds with diverse morphologies as potential inhibitors against the activity of PPO, both in model and real systems. An initial screening of 10 ligands shows that all azamacrocyclic compounds inhibit to some extent the enzymatic browning, but the molecular structure plays a crucial role on the power of inhibition. Kinetic studies of the most active ligand (L2) reveal a S-parabolic I-parabolic noncompetitive inhibition mechanism and a remarkab…
Evaluation of Nonpathogenic Fusarium oxysporum and Pseudomonas fluorescens for Panama Disease Control
2011
Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; Nonpathogenic Fusarium oxysporum endophytes from healthy banana roots were evaluated for their ability to reduce Fusarium wilt of banana (Panama disease). Isolates were identified morphologically and by using species-specific primers. Pathogenicity was confirmed by inoculating banana plantlets in the greenhouse. Nonpathogenic F. oxysporum isolates were grouped into 14 haplotype groups by polymerase chain reaction restriction fragment length polymorphism analysis of the intergenic sp…
A multi-proxy long-term ecological investigation into the development of a late Holocene calcareous spring-fed fen ecosystem (Raganu Mire) and boreal…
2021
Abstract The calcareous substrate of spring-fed fens makes them unique islands of biodiversity, hosting endangered, vulnerable, and protected vascular plants. Hence, spring-fed fens ecosystems require special conservation attention because many of them are destroyed (e.g. drained, forested) and it is extremely difficult or even impossible to restore the unique hydrogeological and geochemical conditions enabling their function. The long-term perspective of paleoecological studies allows indication of former wetland ecosystem states and provides understanding of their development over millennia. To examine the late Holocene dynamics of a calcareous spring-fed fen (Raganu Mire) ecosystem on th…
Chlamyphilone, a Novel Pochonia chlamydosporia Metabolite with Insecticidal Activity
2019
Metabolites from a collection of selected fungal isolates have been screened for insecticidal activity against the aphid Acyrthosiphon pisum. Crude organic extracts of culture filtrates from six fungal isolates (Paecilomyces lilacinus, Pochonia chlamydosporia, Penicillium griseofulvum, Beauveria bassiana, Metarhizium anisopliae and Talaromyces pinophilus) caused mortality of aphids within 72 h after treatment. In this work, bioassay-guided fractionation has been used to characterize the main bioactive metabolites accumulated in fungal extracts. Leucinostatins A, B and D represent the bioactive compounds produced by P. lilacinus. From P. griseofulvum and B. bassiana extracts, griseofulvin an…
Interspecific variation in total phenolic content in temperate brown algae
2017
Marine algae synthesize secondary metabolites such as polyphenols that function as defense and protection mechanisms. Among brown algae, Fucales and Dictyotales (Phaeophyceae) contain the highest levels of phenolic compounds, mainly phlorotannins, that play multiple roles. Four temperate brown algae (Cystoseira amentacea, Cystoseira compressa, Dictyopteris polypodioides and Padina pavonica) were studied for total phenolic contents. Total phenolic content was determined colorimetrically with the Folin-Ciocalteu reagent. Significant differences in total phenolic content were observed between leathery and sheetlike algae and also within each morphological group. Among the four species, the she…
Volatile Components from Aerial Parts of Centaurea diffusa and C. micrantha ssp. melanosticta and Their Biocidal Activity on Microorganisms Affecting…
2018
The chemical composition of the essential oils from aerial parts of two taxa of Centaurea belonging to subgenus Acrolophus, Centaurea diffusa Lam. and C. micrantha Hoff. ssp. melanosticta (Lange) Dostàl, respectively collected in Croatia and Spain, were evaluated by GC and GC-MS. The main components of C. diffusa were hexadecanoic acid (31.1%), ( Z,Z)-9,12-octadecadienoic acid (10.7%) and damascenone isomers (6.4%), whereas hexahydrofarnesyl acetone (27.8%), hexadecanoic acid (8.3%) and caryophyllene oxide (6.4%) were the most abundant components of C. micrantha ssp. melanosticta. The oils showed good antibacterial and antifungal activities against some microorganisms that infest historica…