Taxonomic study of the Japanese Dacrymycetes.

The class Dacrymycetes is a rather small group of brown-rot wood-decaying jelly fungi characterised by forked basidia and an orange to yellow gelatinous to cartilaginous fruit body. In Japan, dacrymycetous fungi had not been investigated for a long time, justifying a taxonomic re-examination. In the present study we attempted an investigation of the dacrymycetous fungal flora of Japan, and recognised 28 taxonomic entities, including five new taxa, i.e. Dacrymyces ancyleus, D. aureosporus, D. pinacearum, D. subarcticus and Dacryopinax sphenocarpa, and nine new records. Due to the present survey, the total number of dacrymycetous species recorded from Japan increased from 28 to 42. Of the newly described species, Dacrymyces ancyleus is characterised by recurved, cylindrical basidiocarps and hyphae with clamp connections. Dacrymyces aureosporus resembles D. chrysospermus, but differs in wall thickness of its marginal hyphae. Dacrymyces pinacearum and D. subarcticus represent new coelomycetous anamorphic species. Dacryopinax sphenocarpa has sharp, spathulate basidiocarps, and hyphae with clamp connections. Descriptions, illustrations and photographs of fruit bodies are presented with some taxonomic notes. Molecular phylogenetic analyses were conducted to verify the species identification, and the remaining problems in Dacrymycetes taxonomy are discussed based on these data.

Mismatch repair and microsatellite instability in esophageal cancer cells.

Using in vitro mismatch repair (MMR) assay, we have identified 3 of 22 esophageal cancer cell lines exhibiting reduced MMR activity. By means of gel-shift assay, decreased binding ability to GT mismatch and CA loop was observed in these 3 cell lines. However, we could not find any mutations in the hMSH2, hMSH3 and hMSH6 genes, the protein products of which exhibit mismatch binding activity in human cells. In addition, when using antibodies against 5 MMR-related proteins (hMSH2, hMSH3, hMSH6, hPMS2 and hMLH1), no aberrant expression was detected in any of them. When we examined 9 microsatellite loci in endogenous genomic DNA, these 3 esophageal cancer cell lines, deficient in MMR, did not exhibit microsatellite instability. However, when we examined the repetitious sequence on exogenous plasmid DNA which was introduced into these 3 esophageal cancer cells, the results suggested that MMR deficiency in esophageal cancer cells could result in moderate instability of the exogenous sequence.

Novel human topoisomerase I inhibitors, topopyrones A, B, C and D. I. Producing strain, fermentation, isolation, physico-chemical properties and biological activity.

In the course of a screening program for specific inhibitors of human topoisomerase I using a recombinant yeast, we have discovered four new active compounds. All four compounds were isolated from the culture broth of a fungus, Phoma sp. BAUA2861, and two of them were isolated from the culture broth of a fungus, Penicillium sp. BAUA4206. We designated these compounds as topopyrones A, B, C and D. Topopyrones A, B, C and D selectively inhibited recombinant yeast growth dependent on expression of human topoisomerase I with IC50 values of 1.22, 0.15, 4.88 and 19.63 ng/ml, respectively. The activity and selectivity of topopyrone B were comparable to those of camptothecin. The relaxation of supercoiled pBR322 DNA by human DNA topoisomerase I was inhibited by these compounds, however they did not inhibit human DNA topoisomerase II. Topopyrones A, B, C and D were cytotoxic to all tumor cell lines when tested in vitro. Topopyrone B has potent inhibitory activity against herpesvirus, especially varicella zoster virus (VZV). It inhibited VZV growth with EC50 value of 0.038 microg/ml, which is 24-fold stronger than that of acyclovir (0.9 microg/ml). Topopyrones A, B, and C were inhibitory to Gram-positive bacteria.

Glomosporin, a novel antifungal cyclic depsipeptide from Glomospora sp. I. Production, isolation, physico-chemical properties and biological activities.

A novel antifungal cyclic depsipeptide termed glomosporin, which has a fatty acyl side chain, was isolated from a barley solid culture of Glomospora sp. The strain was isolated from fallen pine leaves collected in Fukusima Prefecture, Japan and identified as Glomospora sp. BAUA 2825. Glomosporin was purified by butanol extraction followed by preparative HPLC. Glomosporin showed antimicrobial activity against fungi including clinically important Aspergillus fumigatus.