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Serpula himantioides is a widely distributed wood rot fungus that causes heart rot in various tree species. In Japan, heart rot associated with S. himantioides occurs in Chamaecyparis pisifera; however, its distribution within living trees and changes in its abundance as decay progresses remain unclear. In this study, we used a real‐time polymerase chain reaction (real‐time PCR) assay to specifically detect and quantify S. himantioides in wood. This allowed us to determine the distribution of S. himantioides in living C. pisifera and to monitor changes in its abundance as decay progressed. In addition, the mode of decay progression was characterized using nonhierarchical clustering. Serpula himantioides was detected from both decayed and undecayed heartwood and at sites as high as 12 m in the trunk, suggesting that it was widely distributed in the heartwood. The clustering analysis grouped samples into three clusters corresponding to the incipient, intermediate and advanced stages of decay. The abundance of S. himantioides increased from the incipient stage to the intermediate stage of decay and decreased at the advanced stage. The results quantitatively showed that intermediate stage decay moved up the trunk and replaced the part corresponding to the incipient stage as decay progressed. These results will be useful for devising methods for the early detection of heart rot caused by S. himantioides and to understand the progress of decay caused by wood rot fungi in living trees. [ABSTRACT FROM AUTHOR]

Serpula himantioides is a widely distributed saprotrophic fungus that causes root and butt rot in various tree species. In Japan, butt rot associated with S. himantioides is observed in Chamaecyparis pisifera and Abies sachalinensis. Previous studies have shown that S. himantioides includes five phylogenetically defined cryptic lineages, but the placement of Japanese isolates remains unclear. To clarify the phylogenetic relationship between Japanese S. himantioides and the five known lineages, we conducted a phylogenetic analysis using three newly collected Japanese isolates along with 74 S. himantioides isolates, based on the internal transcribed spacer (ITS) region, the 28 S large subunit (LSU) rDNA, the beta‐tubulin (tub) gene, and the heat stress protein (hsp) gene. The concatenated phylogenetic tree showed that Japanese isolates composed a clade with a high bootstrap value distinct from the known lineages, indicating the Japanese isolates present a new cryptic lineage of S. himantioides. [ABSTRACT FROM AUTHOR]

The adsorption of methylviologen dications (MV2+) on single‐crystalline Au electrodes in both H2SO4 and HClO4 was examined. MV2+ strongly interacted with sulfate and bisulfate anions adsorbed on the Au(111) electrode surface in 0.05 M H2SO4 under a controlled potential of 1.25 V vs. the reversible hydrogen electrode (RHE). A characteristic non‐Faradaic current was observed at 1.10 V vs. RHE. When adsorption of MV2+ was carried out in 0.1 M HClO4, the electrochemical response of MV2+ was less than that obtained in H2SO4. The results show that the formation of a highly ordered sulfate/bisulfate adlayer plays an important role in the formation of condensed MV2+ layers. Examination of polycrystalline Au and Au(100) electrodes revealed a poor electrochemical response due to the surface roughness of the Au substrate, but the electrochemical detection was applicable to polycrystalline Au electrodes. A systematic investigation of the structural dependency of viologen derivatives showed that molecular size is important for electrostatic interactions with a highly ordered sulfate/bisulfate adlayer. The findings of the present study demonstrate successful detection of MV2+ at a concentration of ≤1 pM with a non‐Faradaic current. [ABSTRACT FROM AUTHOR]