Taxonomic revision of Pseudolachnea and Pseudolachnella and establishment of Neopseudolachnella and Pseudodinemasporium gen. nov.

The taxonomy of Pseudolachnea and Pseudolachnella is controversial. Some authors have regarded them as congeneric, whereas others have considered them to be distinct genera differentiated merely on the number of conidial septa. A total of 26 isolates of Pseudolachnea-like fungi were subjected to morphological examination and phylogenetic analyses of nuc rDNA internal transcribed spacers 1 and 2 and partial 28S sequences and partial sequence of the translation elongation factor 1α gene. The results indicated that our materials should be classified in four genera: Pseudolachnea, Pseudolachnella, and two new genera, Neopseudolachnella and Pseudodinemasporium. Although the monophyly of both Pseudolachnea and Pseudolachnella was confirmed, it was concluded that differences observed in the conidiomatal structure, such as thickness of basal stroma and the excipulum, were more reliable for their circumscription, instead of conidial septation. Neopseudolachnella was similar to Pseudolachnea and Pseudolachnella in conidial morphology but was characterized by the conidiomata lacking an excipulum, unlike members of the latter two genera. Pseudodinemasporium bore conidia morphologically similar to those of Dinemasporium but was differentiated from the latter by the conidiomata, which was composed of a well developed peridial structure. A total of 12 new species, namely three in Neopseudolachnella (N. acutispora, N. magnispora, N. uniseptata), one in Pseudodinemasporium (P. fabiforme) and eight in Pseudolachnella (P. asymmetrica, P. botulispora, P. brevicoronata, P. campylospora, P. complanata, P. falcatispora, P. fusiformis and P. pachyderma) are described and illustrated.

Lambertellin system, the mechanism for fungal replacement of Monilinia fructigena with Lambertella corni-maris without competitive inhibition on agar media.

The 'Lambertellin system' was disclosed which rationally explains the fungal replacement (mycoparasitism) of Monilinia fructigena (M. f., the host) with Lambertella corni-maris (L. corni-maris, the parasite) without competitive inhibition in the simultaneous incubations on agar media. The 'Lambertellin system' involves; (a) L. corni-maris secretes nontoxic lambertellols (1, 2) as the diffusible precursors of the authentic responsible substance 3 regardless of existence of the host M. f.; (b) In the absence of the host, the environment around the parasite is kept under neutral condition, and both 1 and 2 are readily transformed into 3; (c) Lambertellin (3) inhibits not only the host but also the parasite. The parasite degrades 3 for detoxification; and (d) Upon the host M. f. approaching closely to the area where the parasite inhabits, the environment around the parasite becomes acidic to stabilize 1 and 2, which gives them a chance to diffuse into the host area. Then these are gradually transformed into 3 to inhibit the host without damaging the parasite. This mechanism also accords with the progress of 'Natsu-Nenju' disease on apple fruits, which is known to be a mysterious phyto-disease because of two unique stages of its lifecycle, anamorphic (asexual) and teleomorphic (sexual). The 'Lambertellin system' would be categorized as a novel class of alleropathies.

Host jumping onto close relatives and across kingdoms by Tyrannicordyceps (Clavicipitaceae) gen. nov. and Ustilaginoidea_(Clavicipitaceae).

PREMISE OF STUDY: This research seeks to advance understanding of conditions allowing movement of fungal pathogens among hosts. The family Clavicipitaceae contains fungal pathogens exploiting hosts across three kingdoms of life in a pattern that features multiple interkingdom host shifts among plants, animals, and fungi. The tribe Ustilaginoideae potentially represents a third origin of plant pathogenesis, although these species remain understudied. Fungal pathogens that cause ergot are linked morphologically with Clavicipitaceae, but are not yet included in phylogenetic studies. The placement of Ustilaginoideae and ergot pathogens will allow differentiation between the host habitat and host relatedness hypotheses as mechanisms of phylogenetic diversification of Clavicipitaceae. METHODS: A multigene data set was assembled for Clavicipitaceae to test phylogenetic placement and ancestral character-state reconstructions for Ustilaginoidea virens and U. dichromonae as well as the ergot mycoparasite Cordyceps fratricida. Microscopic morphological observations of sexual and asexual states were also performed. KEY RESULTS: Phylogenetic placement of U. virens and U. dichromonae represents a third acquisition of the plant pathogenic lifestyle in Clavicipitaceae. Cordyceps fratricida was also placed in Clavicipitaceae and recognized as a new genus Tyrannicordyceps. Ancestral character state reconstructions indicate initially infecting hemipteran insect hosts facilitates subsequent changes to a plant pathogenic lifestyle. The ancestor of T. fratricida is inferred to have jumped from grasses to pathogens of grasses. CONCLUSIONS: The host habitat hypothesis best explains the dynamic evolution of host affiliations seen in Clavicipitaceae and throughout Hypocreales. Co-occurrence in the same habitat has allowed for host shifts from animals to plants, and from plants to fungi.

Syntheses of lambertellols and their stable analogues; investigation of the real active species in the mycoparasitism by Lambertella species.

Lambertellols A (1) and B (2), isolated from mycoparasites Lambertella species, were synthesized. The synthesis features intramolecular aldol-type cyclizations of aldehydes 12 and 14 and site specific oxidations of 1-hydroxylambertellols as key steps. The synthesis also provided all diastereomers of 1-hydrolambertellols 17-19 and 25. Chiral resolution made the optically active forms available, which enabled the investigation of the real active species in the mycoparasitism by Lambertella species against Monilinia fructigena. These experiments suggested that lambertellin (3) is responsible for this phenomenon. Chemically labile 1 and 2 should be converted to 3 during the bioassay. The parasite may excrete 1 and 2 as readily diffusible forms, which are then transformed into 3 to inhibit the host M. fructigena. The parasite may have acquired this "drug delivery system" mechanism as an evolutionary enhancement.

Stimulation of the biosynthesis of the antibiotics lambertellols by the mycoparasitic fungus Lambertella corni-maris under the acidic conditions produced by its host fungus in vitro.

The filamentous fungus, Lambertella corni-maris (L. corni-maris), a mycoparasite on Monilinia fructigena, produces the antibiotics, lambertellols A (1), B (2), and lambertellin (3), in a substantial amounts under acidic conditions, whereas these antibiotics were hardly detected when the fungus was cultured on a potato-sucrose (PS) medium without added acids. Our investigations also revealed that the host, M. fructigena, changed its surroundings into acidic conditions, suggesting that the acidic conditions acted as kairomones that stimulated the production of 1-3.

Biosynthesis of lambertellols based on the high specific incorporation of the 13C-labeled acetates and their biological properties.

Biosyntheses of lambertellols A (1) and B (2) as well as lambertellin (3) were investigated by isotope labeling experiments. Nearly 40% of specific incorporation of [1,2-(13)C(2)]acetate was achieved, and all the carbons in 1 and 2 were labeled. This high incorporation of the labeled acetate was realized by providing INADEQUATE spectra by employing only 0.4 and 0.7 mg of 1 and 2, respectively. Our studies revealed that 1-3 are biogenetically synthesized via loss of two carbons from octameric acetate. A biological assay against Monilinia fructicola revealed those remarkably inhibited hyphal germinations. However, neither of them killed the spores immediately, even in high concentration. These conditions induced the formation of microconidia.

Lambertellols A and B, novel 3,4-dihydronaphthalen-1(2H)-ones with spiro-butenolide produced by Lambertella sp.1346.

[structure: see text] Lambertella sp. 1346 was found to produce lambertellols A (1) and B (2) carrying a novel dihydronaphthalen-1(2H)-ones with spiro-1-furan-2(5'H)-one. The spiro-lactone ring moiety of both 1 and 2 were easily migrated to afford lambertellin, a known metabolite of Lambertella corni-maris. The absolute stereochemistry of these compounds was established on the basis of CD spectrum after chemical derivatization.

Novel mutations of neurofibromatosis type 1 gene in small cell lung cancers.

PURPOSE: Mutations in the GTPase-activating protein-related domain (GRD) of the von Recklinghausen neurofibromatosis type 1 (NF1) gene have been reported in several tumors that were not previously associated with NF1. We analyzed 37 cases of lung cancer, including 9 cases of small cell carcinoma, to detect mutations in this domain. METHODS: DNA was extracted from the tumors, and single-strand conformation polymorphism and direct sequencing were used to detect mutations. RESULTS: Three cases of small cell carcinoma had mutations in NF1-GRD. There were two incidences of an A --> G transition at the second base of codon 1415 resulting in Glu --> Gly substitution, and one incidence of an A --> G transition at the third base of codon 1411 (Pro) without amino acid substitution. All three patients had both hilar and mediastinal lymphatic metastasis. CONCLUSIONS: A mutation in this region could imply a poor prognosis.