We investigated the biogeographic history of Kalopanax septemlobus, one of the most widespread temperate tree species in East Asia, using a combined phylogeographic and palaeodistribution modelling approach. Range-wide genetic differentiation at nuclear microsatellites (G'(ST) = 0.709; 2205 samples genotyped at five loci) and chloroplast DNA (G(ST) = 0.697; 576 samples sequenced for 2055 bp at three fragments) was high. A major phylogeographic break in Central China corresponded with those of other temperate species and the spatial delineation of the two temperate forest subkingdoms of East Asia, consistent with the forests having been isolated within both East and West China for multiple glacial-interglacial cycles. Evidence for multiple glacial refugia was found in most of its current range in China, South Japan and the southernmost part of the Korean Peninsula. In contrast, lineage admixture and absence of private alleles and haplotypes in Hokkaido and the northern Korean Peninsula support a postglacial origin of northernmost populations. Although palaeodistribution modelling predicted suitable climate across a land-bridge extending from South Japan to East China during the Last Glacial Maximum, the genetic differentiation of regional populations indicated a limited role of the exposed sea floor as a dispersal corridor at that time. Overall, this study provides evidence that differential impacts of Quaternary climate oscillation associated with landscape heterogeneity have shaped the genetic structure of a wide-ranging temperate tree in East Asia.

Community-level mass flowering, known as general flowering, which occurs in South-East Asia at supra-annual irregular intervals, is considered a particularly spectacular phenomenon in tropical ecology. Recent studies have proposed several proximate factors inducing general flowering, such as drought and falls in minimum temperature. However, limited empirical data on the developmental and physiological processes have been available to test the significance of such factors. To overcome this limitation and test the hypotheses that general flowering is triggered by the proposed factors, we conducted an ‘ecological transcriptome’ study of a mass flowering species, Shorea beccariana, comparing meteorological data with genome-wide expression patterns obtained using next-generation sequencing. Among the 98 flowering-related genes identified, the homologs of a floral pathway integrator, SbFT, and a floral repressor, SbSVP, showed dramatic transcriptional changes before flowering, and their flowering functions were confirmed using transgenic Arabidopsis thaliana. Expression in drought-responsive and sucrose-induced genes also changed before flowering. All these expression changes occurred when the flowering-inducing level of drought was reached, as estimated using data from the preceding 10 years. These genome-wide expression data support the hypothesis that drought is a trigger for general flowering.

We investigated the predispersal survivorship of seeds of six dipterocarp species (Dipterocarpus globosus, D. tempehes, Dryobalanops aromatica, D. lanceolata, Shorea beccariana, and S. pilosa) during 2001–2002, when a general flowering occurred in Lambir Hills National Park, Sarawak, Malaysia. More immature seeds dropped during the first month in Dryobalanops and Shorea spp. than in Dipterocarpus spp. Insects attacked the seeds of all species during all developmental stages through to maturity, although temporal patterns varied among the dipterocarps. In contrast, arboreal vertebrates only occasionally ate seeds, and produced less damage than insects. In four species, insects damaged a significantly higher percentage of seeds than did vertebrates. Direct observations of seed survival patterns and bagging experiments using two sizes of mesh (cloth and wire) in the canopy of Dryobalanops aromatica identified insects as the principal seed predators during both the last phase, and overall. These results document the relative importance of insects as predispersal seed predators in these dipterocarp species.

Objective. Methotrexate (MTX) is used as an anchor drug for rheumatoid arthritis (RA). Lymphoproliferative disease (LPD) occasionally develops in patients treated with MTX, and is known as MTX-associated LPD (MTX-LPD).Although MTX-LPD occurs mainly in RA patients, it has not been established if MTX administration is an independent risk factor for LPD in RA patients. We examined the clinical characteristics of MTX-LPD in Japanese RA patients and attempted to determine the risk factors for MTX-LPD development. Methods. We performed a nested case-control study on RA patients. We enrolled 5,753 RA patients from Kagawa, Japan. In age-and sex-matched patients, we separated patients who did not develop LPD under MTX treatment (MTX non-LPD group) from those that did (MTX-LPD group) and conducted a comparative examination. We used multivariate analysis to determine the independent risk factors for MTX-LPD onset. Results. There were 28 patients in the MTX-LPD group and 125 patients in the MTX non-LPD group. Multivariate analysis of the parameters extracted by univariate analysis revealed that the mean MTX dose was a risk factor for MTX-LPD after adjusting for age; therefore, higher MTX dose is associated with LPD onset in RA patients. Conclusion. MTX is an independent risk factor for LPD onset in Japanese RA patients.