Transcription and Translation Products of the Cytolysin Gene psm-mec on the Mobile Genetic Element SCCmec Regulate Staphylococcus aureus Virulence

The F region downstream of the mecI gene in the SCCmec element in hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) contains two bidirectionally overlapping open reading frames (ORFs), the fudoh ORF and the psm-mec ORF. The psm-mec ORF encodes a cytolysin, phenol-soluble modulin (PSM)-mec. Transformation of the F region into the Newman strain, which is a methicillin-sensitive S. aureus (MSSA) strain, or into the MW2 (USA400) and FRP3757 (USA300) strains, which are community-acquired MRSA (CA-MRSA) strains that lack the F region, attenuated their virulence in a mouse systemic infection model. Introducing the F region to these strains suppressed colony-spreading activity and PSMα production, and promoted biofilm formation. By producing mutations into the psm-mec ORF, we revealed that (i) both the transcription and translation products of the psm-mec ORF suppressed colony-spreading activity and promoted biofilm formation; and (ii) the transcription product of the psm-mec ORF, but not its translation product, decreased PSMα production. These findings suggest that both the psm-mec transcript, acting as a regulatory RNA, and the PSM-mec protein encoded by the gene on the mobile genetic element SCCmec regulate the virulence of Staphylococcus aureus

Comparative Analyses of Dormancy-associated MADS-box Genes, PpDAM5 and PpDAM6, in Low- and High-chill Peaches (Prunus persica L.)

This study investigated the regulation of the seasonal expression of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to the endodormancy and development of lateral vegetative and flower buds of low- and high-chill peach cultivars. PpDAM5 and PpDAM6 were originally found as homologs of Arabidopsis SVP/AGL24 at the EVERGROWING (EVG) locus of peach and have been recently shown to be involved in lateral bud endodormancy. Seasonal expression analyses in this study indicated that PpDAM5 and PpDAM6 transcript levels in lateral vegetative buds of both low- and high-chill cultivars in the field negatively correlated with bud burst percentages determined under forcing conditions. Negative correlation was also found between their transcript levels and the flower organ enlargement rate. These results suggest that distinct seasonal expression patterns of PpDAM5 and PpDAM6 are correlated with a distinct chilling requirement for bud break and flowering of low- and high-chill cultivars. Characterization of the genomic structure of PpDAM5 and PpDAM6 revealed the presence of large insertions in the first introns of both PpDAM5 and PpDAM6 in low-chill peach. Alteration of the genomic structure is discussed with respect to the low-chill character

モモ多低温要求性品種と少低温要求性品種における休眠関与 MADS-box 遺伝子，PpDAM5, PpDAM6 遺伝子の比較解析

This study investigated the regulation of the seasonal expression of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to the endodormancy and development of lateral vegetative and flower buds of low- and high-chill peach cultivars. PpDAM5 and PpDAM6 were originally found as homologs of Arabidopsis SVP/AGL24 at the EVERGROWING (EVG) locus of peach and have been recently shown to be involved in lateral bud endodormancy. Seasonal expression analyses in this study indicated that PpDAM5 and PpDAM6 transcript levels in lateral vegetative buds of both low- and high-chill cultivars in the field negatively correlated with bud burst percentages determined under forcing conditions. Negative correlation was also found between their transcript levels and the flower organ enlargement rate. These results suggest that distinct seasonal expression patterns of PpDAM5 and PpDAM6 are correlated with a distinct chilling requirement for bud break and flowering of low- and high-chill cultivars. Characterization of the genomic structure of PpDAM5 and PpDAM6 revealed the presence of large insertions in the first introns of both PpDAM5 and PpDAM6 in low-chill peach. Alteration of the genomic structure is discussed with respect to the low-chill character

Controlling Formation of Single-Molecule Junctions by Electrochemical Reduction of Diazonium Terminal Groups

We report controlling the formation of single-molecule junctions by means of electrochemically reducing two axialdiazonium terminal groups on a molecule, thereby producing direct Au–C covalent bonds <i>in situ</i> between the molecule and gold electrodes. We report a yield enhancement in molecular junction formation as the electrochemical potential of both junction electrodes approach the reduction potential of the diazonium terminal groups. Step length analysis shows that the molecular junction is significantly more stable, and can be pulled over a longer distance than a comparable junction created with amine anchoring bonds. The stability of the junction is explained by the calculated lower binding energy associated with the direct Au–C bond compared with the Au–N bond