Littérature scientifique sur le sujet « Pseudevernia »

AbstractMannitol-1-phosphate dehydrogenase [EC 1.1.1.17] activity was demonstrated in extracts of Pseudevernia furfuracea and Hypogymnia physodes. The reaction was found to be highly substrate specific for fructose-6-phosphate/NADH or mannitol-1-phosphate/NAD+. The pH optimum for fructose-6-phosphate reduction was 7.1, and apparent Km values were 1.2 mM for fructose-6-phosphate and 20 μM for NADH. The reaction did not require Mg++ or Ca++. For conversion of mannitol-1-phosphate into mannitol, the occurrence of mannitol-1-phosphatase in Pseudevernia furfuracea is postulated.

Определены концентрации Ni, Cu, Pb, Cd, Fe, Mn, Zn в лишайниках Hypogymnia physodes (L.) Nyl., Pseudevernia furfuracea (L.) Zopf. на ели европейской, сосне обыкновенной и можжевельнике обыкновенном. Лишайники на юго-восточном побережье Ладоги характеризуются низкими концентрациями металлов, которые можно использовать как регионально фоновые. We determined the concentrations of Ni, Cu, Pb, Cd, Fe, Mn, Zn in lichens Hypogymnia physodes (L.) Nyl., Pseudevernia furfuracea (L.) Zopf., collected from the European spruce, Scots pine, and Common juniper. Low concentrations of metals characterize lichens of the southeastern coast of Lake Ladoga. These concentration values can thus be used as basic for the region.

AbstractTwo asexual reproductive strategies of the common lichen Pseudevernia furfuracea are described. Although the species propagates mainly by isidia, some specimens also show the development of soralia. Morphological, chemical and molecular analyses were performed on three such sorediate specimens from the Canary Islands, Morocco and Turkey. Maximum parsimony, maximum likelihood and Bayesian analyses indicate that: a) sorediate samples represent only a morphological variant of the reproductive mode and b) the separation of taxa (at species level or below) on the basis of their containing either olivetoric acid or physodic and oxyphysodic acids is not appropriate. In addition, a phylogenetic reconstruction of the genus Pseudevernia is presented for the first time. The tree shows two sister monophyletic clades, one containing American species (P. intensa, P. cladonia, P. consocians), and the second encompassing the P. furfuracea samples (including sorediate specimens). The biological and taxonomic significance of soralia in sorediate samples is discussed.

Three moss (Pleurosium spp., Polytrichum spp., Rhytidiadelphus spp.) and two lichen taxa (Hypogymnia physodes L., Pseudevernia furfuracea L.), were exposed for four weeks in six petrol stations, two consecutive years (2015–2016), in urban area of the Prešov city (Slovakia), to assess accumulation of selected airborne elements Cd, Co, Cu, Fe, Hg, Mn, Ni, Pb and Zn. Significantly highest (P < 0.01) ability to accumulate Zn, Ni, Co and Fe was found in Pleurosium spp.; Pseudevernia furfuracea was determined the best accumulator of Hg, whereas Rhytidiadelphus spp. was found as the least suitable for this purpose. No significant differences in heavy metal accumulation between moss and lichen taxonomic group were found. Samples of conifer (used as a moss/lichen bag holder) showed significantly lower content of heavy metals compared to mosses and lichens. Major content of heavy metals trapped in the air around petrol stations, did not originate from the petrol combustion, but predominantly from the car body, which is mechanically disrupted during fuelling.

Lichens have widely been used as bioindicators to reflect the quality of the environment. The present study was conducted to investigate the lichens diversity that grows on the surface of waste heaps from an abandoned old copper mine in Mlynky, Slovakia. In spite of the heavy metalcontaminated environment, we documented twenty species of lichens in the selected site. Taxonomically the most numerous group were represented by Cladonia with seven species, as well other species; namely, Acarospora fuscata, Cetraria islandica, Dermatocarpon miniatum, Hypogymnia physodes, Hypogymnia tubulosa, Lecanora subaurea, Lepraria incana, Physcia aipolia, Porpidia macrocarpa, Pseudevernia furfuracea, Rhizocarpon geographicum and Xanthoria parietina. The content of selected heavy metals (Cu, Fe, and Zn) in the predominant lichens Cetraria islandica, Cladonia digitata, Cladonia pyxidata, Hypogymnia physodes and Pseudevernia furfuracea were analyzed. The highest content of Cu, Fe, and Zn was found in Cladonia pyxidata collected from mine-spoil heaps with concentration 46 ± 4.4, 82.5 ± 22.6, 4.8 ± 1.6 mg/kg, respectively. Interestingly, Cladonia pyxidata collected from the forest surrounding the location showed 15 times lower concentration for Cu. Additionally, similar results were found for Fe and Zn.

The structurally unique depsidone furfuric acid (1) has been prepared in one step by the acid-catalysed alkylation of methyl p- orsellinate (6) or of atranorin (4) with physodalic acid (7). This mode of synthesis gives credence to the proposal that (1) is an artefact of the isolation procedure rather than a true metabolite of the lichen Pseudevernia furfuracea .

Pseudevernia furfuracea (L.) Zopf lichen specimens were collected every 5 km starting from around an iron-steel factory located in the central area of Karabük province, up to Yenice Forest. Zn, Cu, Mn, Fe, Pb, Ni, Cd, Cr contents were analyzed in the samples collected from polluted and unpolluted areas. A Pseudevernia furfuracea (L.) Zopf sample from Yenice Forest was used as a control. The reason for this choise was the abundance of species diversity, and therefore sample collection might cause a very low impact on natural population density. The forest is among the 100 forested areas that must be urgently taken under protection according to WWF (World Wildlife Fund) researches. Results of the current study manifested significant variations among the contents of these elements between stations. As expected, the pollution sources, such as iron-steel factory, roads and railroads, industry, heavy traffic, and waste treatment plants, have major impact on the heavy metal accumulation in P. furfuracea (L.) Zopf, and, in accordance to their location, samples 8 and 10 displayed high element accumulation. Surprisingly, although Yenice Forest is under protection, results of our study showed that the region is becoming polluted by the infl uence of many pollution sources in the area. The present study also confirms the efficient metal accumulation capacity of lichens

Pseudevernia furfuracea is a shrubby lichen commonly found around the Baltic Sea. The lichen appears to reproduce mainly by producing isidia, propagules of the lichen cortex. It is very morphologically and chemically diverse and can be found on different substrates, such as nutrient poor bark trees and rocks. The main objective of this study was to describe genetic variation in the ITS region and link this to variations in morphology, substrate ecology and secondary chemistry. In total, 36 specimens of P. furfuracea were collected from 21 sites in Sweden, Finland and Estonia. Seven haplotypes were distinguished in the ITS region. A statistically significant connection between haplotype and colouration of the lichen was found. Lighter coloured specimens of P. furfuracea are more likely to be of the ancestral haplotype. No other significant correlations between the different characteristics studied were found, suggesting that P. furfuracea should be regarded as a single species within the Baltic Sea area. This is also supported by the haplotype network.

Les lichens sont des organismes symbiotiques constitués d'un champignon (mycobionte) associé à une algue et/ou une cyanobactérie (photobionte). Leurs métabolites secondaires sont des molécules originales appartenant au groupe des depsides, depsidones, dibenzofuranes et présentent un intérêt pour la cosmétique et/ou la pharmaceutique en raison de leur propriété antibiotique, anti-inflammatoire, antioxydant, filtre UV. Nous avons choisi d'étudier le lichen Pseudevenia furfuracea qui est l'un des lichens utilisés en tant que matière première pour la parfumerie et la cosmétique (1900 tonnes / an), car il est d'une part abondant dans la nature et d'autre part, il possède des métabolites secondaires très variés. Classiquement, les extraits utilisés sont obtenus par extraction au reflux de solvants organiques; cette méthode à l'inconvénient d'induire des durées d'extractions relativement longues et est consommatrice en solvants. L'objectif de notre travail est d'extraire les métabolites secondaires d'une manière sélective et innovante tout en diminuant la durée d'extraction. Pour cela, nos travaux reposent sur l'extraction assistée sous micro-onde (EAM) combinée ou non aux liquides ioniques. Dans ce dessein, deux familles de liquides ioniques (LIs) "hydrophiles" et "hydrophobes" ayant un cation imidazolium et pyridinium ont été synthétisés. Trois différentes préparations de lichen (mixé, broyé au mortier et broyé planétaire) ont été effectuées en faisant varier la granulométrie et chaque préparation a été étudiée par microscopie électronique à balayage. L'optimisation de l'EAM a été effectuée à une température d'extraction optimale de 75 °C et a permis de générer un énorme gain de temps (24 h sous conditions classiques contre 15 min sous irradiation micro-onde). Une étude comparative des taux d'extraction entre l'EAM et l'extraction en condition classique a été éffectuée par analyse au spectrodensitomètre CAMAG®, celle-ci a montré que la première est plus performante dans la plupart des cas. L'utilisation des liquides ioniques a mis en évidence l'existence d'une sélectivité d'extraction en fonction de la structure des LIs qui résulte d'interactions intermoléculaires entre les LIs et les substances extraites. L'effet de chaque liquide ionique sur la dégradation d'un des métabolites, en particulier l'atranorine, a également été étudié. Également, les interactions entre un liquide ionique et la surface du lichen ont été étudiées par mesure d'angle de contact et par les mesures de Brunauer Emett et Teller. Une extraction à plus grande échelle a été réalisée pour étudier la reproductibilité de la méthode et la possibilité de recycler le liquide ionique
Lichens are symbiotic organisms constituted of fungus (mycobiont) associated to algae and/or cyanobacteria (photobiont). Their secondary metabolites are original molecules belonging to the group of depsides, depsidones, dibenzofurans. Lichens presented special interest for cosmetic and pharmaceutical industry due to their antibiotic, anti-inflammatory, antioxidant and UV filter properties. In this work we focused our study on Pseudevenia furfuracea lichen, which is intensively used as a raw material in perfumery and cosmetics (1900 tons/year), due to its large availability in nature as well as possessing various secondary metabolites. In this work we presented extraction of the secondary metabolites using a selective and innovative solventfree method in shorter extraction time in comparison to the conventional extraction methods requiring under reflux of large quantities of solvents with longer times for extraction. The proposed method is based on the use of microwave irradiation for extraction (MIE) associated to (or not) appropriate ionic liquids. Two kinds of hydrophilic or hydrophobic imidazolium- and pyridinium-based ionic liquids (ILs) were synthesized. Three different methods of grinding for lichen were used, leading to different particle size and the crushed products were observed by scanning electron microscopy (SEM). Heating optimization of MIE was performed during 15 min at optimal temperature (75 °C) (instead of 24 h under conventional heating). A comparative study of extraction rates between MIE and extraction with conventional heating was realized with a CAMAG® spectrodensitometer and results of analysis showed that MIE is efficient in most of the studied cases. The use of ionic liquids showed selectivity for extraction and it depended on the structure of ILs and also intermolecular interactions between ILs and extracted substances.Effect of each ionic liquid on the degradation of one of the secondary metabolites, atranorin, was also been studied. In addition, interactions between IL and the surface of the lichen surface were studied by measurements of the angle of contact and by Brunauer Emett and Teller measurements. Scale-up for extraction was carried out to investigate the reproducibility of the method and the possibility of reuse of the ionic liquid