Testing spore amyloidity in Agaricales under light microscope: the case study of Tricholoma.

Although species of the genus Tricholoma are currently considered to produce inamyloid spores, a novel standardized method to test sporal amyloidity (which involves heating the sample in Melzer's reagent) showed evidence that in the tested species of this genus, which belong in all 10 sections currently recognized from Europe, the spores are amyloid. In two species, T. josserandii and T. terreum, the spores are also partly dextrinoid. This result provides strong indication that a positive reaction of the spores in Melzer's reagent could be a character shared by all genera in Tricholomataceae s. str.

On the Nucleophilic Reactivity of 4,6-Dichloro-5-nitrobenzofuroxan with Some Aliphatic and Aromatic Amines: Selective Nucleophilic Substitution.

The reaction rates for the nucleophilic aromatic substitution of 4,6-dichloro-5-nitrobenzofuroxan 1 with eight aliphatic amines (characterized by very different basicities/nucleophilicities) and three anilines have been measured in both methanol and toluene. The obtained rates have been related to the basicity (pKaH in water and Kb in benzene) or nucleophilicity (N Mayr constants) of the tested amines. The whole of the obtained kinetic data has furnished useful information on the high nucleophilic reactivity of benzofuroxan derivatives, which has been related essentially to two factors: the high electron-drawing ability/power of the condensed furoxan ring and the low aromatic character of the benzofuroxan system.

Calocybella, a new genus for Rugosomyces pudicus (Agaricales, Lyophyllaceae) and emendation of the genus Gerhardtia.

Calocybella is a new genus established to accommodate Rugosomyces pudicus. Phylogenetic analyses based on a LSU-ITS sequence dataset place Calocybella sister to Gerhardtia from which it differs morphologically in the presence of clamp-connections and reddening context. The genus Gerhardtia is emended to also include taxa with smooth spores. According to our morphological analysis of voucher material, Calocybe juncicola s. auct. is shown to be Calocybella pudica.

Atractosporocybe, Leucocybe and Rhizocybe: three new clitocyboid genera in the Tricholomatoid clade (Agaricales) with notes on Clitocybe and Lepista.

A molecular multigene analysis (ITS, 18S and 28S nrLSU ribosomal DNA, tef1, rpb2) was used to support the proposition of three new genera of clitocyboid fungi. Leucocybe is proposed to accommodate the clade formed by Clitocybe connata and C. candicans. Clitocybe inornata is invested as type species of Atractosporocybe, while the new genus, Rhizocybe, is proposed for the former species of section Vernae of Clitocybe, C. vermicularis, C. pruinosa and C. rhizoides. The three lineages are related to the families Lyophyllaceae and Entolomataceae and independent from the Clitocybeae clade. Morphologically Rhizocybe is characterized by the presence of conspicuous rhizomorphs, while Atractosporocybe presents long fusiform spores. Leucocybe includes two whitish species in the former section Candicantes of Clitocybe, but no relevant shared characteristic feature was detected. Other whitish clitocyboid species, such as C. phyllophila (= C. cerussata), C. dealbata, C. rivulosa, and Singerocybe hydrogramma, are shown to be genetically related to the core lineage of the Clitocybeae.

The phylogenetic position of Haasiella (Basidiomycota, Agaricomycetes) and the relationships between H. venustissima and H. splendidissima.

Based on a combined ITS-LSU rDNA analysis, the omphalinoid genus Haasiella is shown to be part of the Hygrophoroid clade and sister to Hygrophorus. H. venustissima and H. splendidissima are conspecific; H. splendidissima is the tetrasporic/clamped and heterothallic form of H. venustissima.

Nucleophilic Substitution Reactions of 1-Halogeno-4-COR-2-nitrobenzenes and 1-Halogeno-6-COR-2-nitrobenzenes with Sodium Benzenethiolate and Piperidine. Can an "Inverted Built-In Solvation" Be Responsible for the Peculiar Activation by an o-Carboxamido Group in S(N)Ar Reactions with an Anionic Nucleophile?

A kinetic study of the title reactions has allowed an interpretation of the higher efficiency of an o-carboxamido group with respect to an o-carbomethoxy group in activating the benzenethiolate-dehalogenation reactions in methanol (k(CONH)()2/k(CO)()2(Me) 2.2-3.0) as due to an interaction between the anionic nucleophile and the hydrogen atoms of the carboxamido group. An inversion of the activating power of the two groups (k(CONH)()2/k(CO)()2(Me) 0.14) in the reactions with the same nucleophile has been observed when they are in a para-position. Moreover, for piperidino-dehalogenation reactions in methanol k(CONH)()2/k(CO)()2(Me) ratios less than unity (0.2-0.6) have been observed independently of the position (ortho or para) of the carboxamido and carbomethoxy groups with respect to the reaction center.