13 research outputs found
A novel clade of sporocarp-forming species of glomeromycotan fungi in the Diversisporales lineage
In the early times of taxonomy of arbuscular mycorrhizal fungi (Glomeromycota), exclusively sporocarpic species were described. Since then the focus has mainly shifted to species forming spores singly. For many of the sporocarpic species, no molecular data have been made available, and their phylogenetic position has remained unclear. We obtained small subunit ribosomal rDNA and internal transcribed spacer data from specimens of glomeromycotan sporocarps from tropical areas that were assigned to three morphospecies. The complete sequence of the 18S small rDNA subunit sequence, internal transcribed spacers (ITS) 1 and 2 and 5.8S rDNA subunit, was determined from a sporocarp of Glomus fulvum. Partial sequences of the small subunit and the other regions were obtained from Glomus pulvinatum and the newly described species Glomus megalocarpum. Molecular phylogenetic analyses placed all species analyzed as a monophyletic sister group to the Diversispora spurca/Glomus versiforme clade group ("Glomus group Câ) within the Diversisporales. The phylogenetic divergence from other known species suggests that this clade may constitute a new genus. These findings will have important consequences for taxon definition in the Diversisporales. They will facilitate identification of these fungi using rDNA sequences within colonized roots or the environmen
Taxonomy of Some Fungi Used by the Songola People (Zaire)
The author describes and illustrates some fungi used as food as medicine by the Songola people of Zaire. The taxa are: Auricularia fuscosuccinea, Pycnoporus sanguineus, Schizophyllum commune, Lentinus sajor-caju, Armillaria camerunensis (P. Henn.) R. Courtec. comb. nov., Cyptotrama songolarum R. Courtec. sp. nov. and Gymnopilus sp., the former four are common in tropical Africa, but the latter three are much rare
Les peuplements fongiques arenicoles des zones littorales occidentales francaises : chorologie et mycocoenologie
SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Current research findings on the effects of selected mushrooms on cardiovascular diseases
International audienceFor about 50 years, scientists have studied the biological activities of Macromycetes on different pathologies. In this article different fungal activities that reduce the effects of risk factors for cardiovascular diseases are reviewed. Among the 17 species tested on animals, 16 demonstrated at least one of the following activities: ability to reduce hypercholesterolemia or to cure dyslipoproteinemia, possibility to decrease arterial hypertension or hyperglycemia, and ability to cure disturbances in platelet aggregation
Activités biologiques des champignons : recherches actuelles sur les facteurs de risque des maladies cardio-vasculaires
International audienc
Antiproliferative Activities of Methanolic Extracts from a Neotropical Ganoderma Species (Aphyllophoromycetideae): Identification and Characterization of a Novel Ganoderic Acid
Investigation of polyols, amino acids and phenolic acids in a taxonomic study of Cortinarius, Subgenus Leprocybe, Section Orellani
International audienceSeven Cortinarius species in sect. Orellani were divided into 6 groups using microscopic features of their basidiospores. Two of these groups contained all specimens of C. speciosissimus and C. orellanoides, with each group having specimens of both species. Chemical methods employing thin-layer chromatography were used to detect polyols, amino acids and phenolic acids among specimens in these groups. The importance of these compounds as well as microscopic characteristics of the basidiospores are discussed in relation to the classification of species. Preliminary data does not confirm synonymy of C. speciosissimus and C. orellanoides, but identical chromatographic fingerprints were detected for C. orellanoides and C. orellanus
Influence of tree species on richness and diversity of epigeous fungal communities in a French temperate forest stand
International audienceConservation Host specificity Nitrogen mineralisation Saprotrophic and ectomycorrhizal (ECM) fungi Species richness Temperate forest a b s t r a c t Epigeous saprotrophic and ectomycorrhizal (ECM) fungal sporocarps were assessed during 7 yr in a French temperate experimental forest site with six 30-year-old mono-specific plantations (four coniferous and two hardwood plantations) and one 150-year-old native mixed deciduous forest. A total of 331 fungal species were identified. Half of the fungal species were ECM, but this proportion varied slightly by forest composition. The replacement of the native forest by mono-specific plantations, including native species such as beech and oak, considerably altered the diversity of epigeous ECM and saprotrophic fungi. Among the six mono-specific stands, fungal diversity was the highest in Nordmann fir and Norway spruce plantations and the lowest in Corsican pine and Douglas fir plantations. Several factors, connected to the mono-specificity of host trees, could be involved in regulating fungal diversity. Interestingly, this study showed a significant negative correlation between fungal species richness and nitrogen mineralisation, indicating that increases in mineral N availability are associated with decline in saprotrophic and ECM community richness. The frequency of occurrence of fruit bodies of 11 edible fungal species that naturally occur in the native forest was modified by the treatments.
Niveau de recolonisation des forĂȘts rĂ©centes par les champignons du sol et la flore herbacĂ©e des forĂȘts anciennes du Nord de la France : Projet ReForRe. Rapport final
Le projet ReForRe, « Niveau de recolonisation des forĂȘts rĂ©centes par les champignons du sol et
la flore herbacĂ©e des forĂȘts anciennes du Nord de la France », visait Ă Ă©tudier les diffĂ©rences de
biodiversitĂ© entre forĂȘts anciennes et forĂȘts rĂ©centes du Nord de la France.
Le territoire de la France a Ă©tĂ© fortement dĂ©boisĂ© depuis lâinstallation des premiers agriculteurs
néolithiques, il y a plus de 7 000 ans. Mais, dans la premiÚre moitié du XIXe siÚcle, cette
tendance sâest inversĂ©e. Contrairement Ă une opinion rĂ©pandue, les forĂȘts progressent
maintenant en surface. Leur superficie a doublĂ© depuis 2 siĂšcles et elles continuent de sâĂ©tendre
Ă un rythme rapide. Dâimmenses surfaces agricoles (anciennes terres labourables, vignes,
vergers, prairies de fauches ou pĂątures) ont Ă©tĂ© recolonisĂ©es par les forĂȘts. Nous pouvons donc
distinguer deux types de forĂȘts dans les paysages actuels : les « forĂȘts anciennes », qui prĂ©existaient
Ă ce minimum forestier du XIXe siĂšcle, et les « forĂȘts rĂ©centes », apparues depuis.
Ces diffĂ©rences entre forĂȘts rĂ©centes et anciennes doivent ĂȘtre bien sĂ©parĂ©es des diffĂ©rences
entre forĂȘts jeunes et matures (ĂągĂ©es). Une forĂȘt ancienne peut ĂȘtre composĂ©e de trĂšs jeunes
peuplements et, Ă lâinverse, on peut trouver des gros et vieux bois dans une forĂȘt rĂ©cente
(jusquâĂ 200 ans environ). Le concept de forĂȘts anciennes et rĂ©centes concerne la continuitĂ© de
lâĂ©tat boisĂ© dâun territoire, pas lâĂąge des arbres quâil porte.
De nombreux travaux de recherche, menĂ©s en Europe et aux USA, ont montrĂ© que les forĂȘts
rĂ©centes diffĂšrent fortement des forĂȘts anciennes. En particulier, les sols des forĂȘts rĂ©centes ont
souvent Ă©tĂ© enrichis par lâagriculture passĂ©e. En consĂ©quence, la biodiversitĂ© des forĂȘts
anciennes et rĂ©cente nâest pas la mĂȘme. De plus, les espĂšces de forĂȘt ancienne ont souvent un
pouvoir de dispersion trĂšs faible. Elles nâarrivent pas Ă recoloniser les forĂȘts rĂ©centes depuis les
forĂȘts anciennes, oĂč elles sont rĂ©fugiĂ©es, mĂȘme plusieurs centaines dâannĂ©es aprĂšs lâabandon
dâune zone agricole. Ces observations ont Ă©tĂ© faites presque exclusivement sur une unique
composante de la biodiversité, les plantes du sous-bois.
Devant lâimportance de ce phĂ©nomĂšne et lâintĂ©rĂȘt de ces forĂȘts comme rĂ©servoirs de biodiversitĂ© forestiĂšre, plusieurs rĂ©gions de France et dâEurope se sont engagĂ©es dans des programmes de vectorisation et gĂ©orĂ©fĂ©rencement de cartes anciennes afin de pouvoir localiser prĂ©cisĂ©ment et Ă©valuer la part que reprĂ©sentent les forĂȘts anciennes dans les paysages.
Lâex-rĂ©gion Nord-Pas-de-Calais prĂ©sente la particularitĂ© dâĂȘtre aujourdâhui lâune des zones les moins boisĂ©es de France. Les forĂȘts anciennes y sont donc trĂšs probablement plus rares encore quâailleurs. Or, aucune digitalisation des forĂȘts anciennes nây avait Ă©tĂ© encore rĂ©alisĂ©e. Et les espĂšces vĂ©gĂ©tales liĂ©es Ă lâanciennetĂ© de lâĂ©tat boisĂ© nây avaient donc pas encore Ă©tĂ© identifiĂ©es.
Nous avons, dans le présent projet :
- établi une carte précise du boisement pour les deux départements du Nord et du Pas-de-Calais dans la premiÚre moitié du XIXe siÚcle ;
- analysĂ©, par croisement avec les cartes forestiĂšres actuelles, lâanciennetĂ© de lâĂ©tat boisĂ© dans la rĂ©gion et les modalitĂ©s de lâĂ©volution forestiĂšre depuis deux siĂšcles ;
- recherchĂ© les espĂšces vĂ©gĂ©tales liĂ©es aux forĂȘts anciennes ou rĂ©centes (bioindicatrices) ;
- testĂ© si une autre composante de la biodiversitĂ©, les champignons du sol, Ă©tait aussi impactĂ©e par lâanciennetĂ© de lâĂ©tat boisĂ©. Cette derniĂšre partie du programme ReFoRe reprĂ©sente une originalitĂ© forte par rapport aux travaux effectuĂ©s jusquâĂ maintenant dans toutes les autres rĂ©gions de France