Phylogenetic analysis of eastern Asian and eastern North American disjunct Lespedeza (Fabaceae) inferred from nuclear ribosomal ITS and plastid region sequences

Lespedeza (tribe Desmodieae, Fabaceae) follows a disjunct distribution in eastern Asia and eastern North America. Phylogenetic relationships among its species and related taxa were inferred from nuclear ribosomal internal transcribed spacer (ITS) and plastid sequences (trnH‐psbA, psbK‐psbI, trnK‐matK and rpoC1). We examined 35 species of Lespedeza, two of Kummerowia and one of Campylotropis, the sole constituents of the Lespedeza group. An analysis of these data revealed that the genus Campylotropis is sister to the other two genera. However, we were unable to resolve the relationships between Kummerowia and Lespedeza in the strict consensus trees of parsimony analyses based on plastid and combined DNA data. In the genus Lespedeza, the Old World subgenus Macrolespedeza is monophyletic, whereas the transcontinental subgenus Lespedeza is paraphyletic. Monophyly of eastern Asian species and of North American species is strongly supported. Although inconsistent with the traditional classification, this phylogenetic finding is consistent with seedling morphology. Three subgroups recognized in subgenus Macrolespedeza were unresolved in our phylogenetic trees. An incongruence length difference (ILD) test indicated that the two partitions (nuclear ITS and plastid sequences) were significantly incongruent, perhaps because of hybridization between species in Lespedeza. Most of the primary clades of tribe Desmodieae are Asian, implying that the relatively few New World ones, such as those in Lespedeza, are more recently derived from Asia. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 221–235.     

Phenology shifts at start vs. end of growing season in temperate vegetation over the Northern Hemisphere for the period 1982–2008

Changes in vegetative growing seasons are dominant indicators of the dynamic response of ecosystems to climate change. Therefore, knowledge of growing seasons over the past decades is essential to predict ecosystem changes. In this study, the long‐term changes in the growing seasons of temperate vegetation over the Northern Hemisphere were examined by analyzing satellite‐measured normalized difference vegetation index and reanalysis temperature during 1982–2008. Results showed that the length of the growing season (LOS) increased over the analysis period; however, the role of changes at the start of the growing season (SOS) and at the end of the growing season (EOS) differed depending on the time period. On a hemispheric scale, SOS advanced by 5.2 days in the early period (1982–1999) but advanced by only 0.2 days in the later period (2000–2008). EOS was delayed by 4.3 days in the early period, and it was further delayed by another 2.3 days in the later period. The difference between SOS and EOS in the later period was due to less warming during the preseason (January–April) before SOS compared with the magnitude of warming in the preseason (June–September) before EOS. At a regional scale, delayed EOS in later periods was shown. In North America, EOS was delayed by 8.1 days in the early period and delayed by another 1.3 days in the later period. In Europe, the delayed EOS by 8.2 days was more significant than the advanced SOS by 3.2 days in the later period. However, in East Asia, the overall increase in LOS during the early period was weakened in the later period. Admitting regional heterogeneity, changes in hemispheric features suggest that the longer‐lasting vegetation growth in recent decades can be attributed to extended leaf senescence in autumn rather than earlier spring leaf‐out.     

Ceramide Inhibits Cell Proliferation through Akt/PKB Inactivation and Decreases Melanin Synthesis in Mel‐Ab Cells

Ceramide is a bioactive sphingolipid that mediates a variety of cell functions. However, the effects of ceramide on cell growth and the melanogenesis of melanocytes are not known. In the present study, we investigated the actions of cell‐permeable ceramide and its possible role in the signaling pathway of a spontaneously immortalized mouse melanocyte cell line, Mel‐Ab. Our results show that C₂‐ceramide inhibits DNA synthesis in Mel‐Ab cells and G361 human melanoma cells in a dose‐dependent manner. Cell cycle analysis confirmed the inhibition of DNA synthesis by a reduction in the S phase. To investigate the ceramide signaling pathway, we studied whether C₂‐ceramide is able to influence extracellular signal‐regulated kinase (ERK) and/or Akt/protein kinase B (PKB) activation. We demonstrated that phosphorylated Akt/PKB is decreased by C₂‐ceramide, whereas phosphorylated ERK was only slightly affected. Therefore, the C₂‐ceramide‐induced inactivation of Akt/PKB may be closely related to the reduced cell proliferation of Mel‐Ab cells. Furthermore, we assessed the effects of C₂‐ceramide on the pigmentation of Mel‐Ab cells. The results obtained showed that the melanin content of cells was significantly reduced by C₂‐ceramide at concentrations in the range of 1–10 μM, and that the pigmentation‐inhibiting effect of C₂‐ceramide is much greater than that of kojic acid at 1–100 μM. In addition, we found that the activity of tyrosinase is reduced by C₂‐ceramide treatment. Our results demonstrate that C₂‐ceramide reduces the pigmentation of Mel‐Ab cells by inhibiting tyrosinase activity.     

High Frequency of Plant Production via Somatic Embryogenesis from Callus or Cell Suspension Cultures inEleutherococcus senticosus

Hypocotyl segments ofEleutherococcus senticosuscultured on Murashigeand Skoog's (MS) medium with 4.5 µM2,4-D produced somaticembryos directly from the surface of explants without interveningcallus formation. When these somatic embryos were subculturedto the same MS medium with 4.5 µM2,4-D, friable embryogeniccalli were formed mainly from radicle tips of somatic embryos,but at a low frequency (5%). Selected embryogenic calli weremaintained on MS agar or liquid medium with 4.5 µM2,4-D.To induce somatic embryo development, embryogenic calli andcell clumps were transferred to MS medium lacking 2,4-D. Thefrequency of somatic embryo formation differed between culturetypes with 1570 embryos formed per Petri dish from callus cultureand 5514 embryos formed per flask from cell suspension cultures.Somatic embryos formed on agar medium had larger cotyledonsthan those of embryos formed in liquid medium. GA₃treatmentwas necessary to induce germination from somatic embryos. Therate of plant conversion was 97% in somatic embryos from callusculture and 76% in embryos from liquid culture. Regeneratedplantlets were successfully acclimatized in the glasshouse.Copyright1999 Annals of Botany Company Eleutherococcus senticosus, micro propagation, somatic embryogenesis.     

Human mesenchymal stromal cells do not promote recurrence of soft tissue sarcomas in mouse xenografts after radiation and surgery

Background. Mesenchymal stromal cells (MSCs) promote wound healing, including after radiotherapy (RT) and surgery. The use of MSCs in regenerative medicine in the context of malignancy, such as to enhance wound healing post-RT/surgery in patients with soft tissue sarcomas (STSs), requires safety validation. The aim of this study was to determine the effects of human MSCs on STS growth in vitro and local recurrence and metastasis in vivo. Methods. Human primary STS and HT-1080 fibrosarcoma lines were transduced to express luciferase/eGFP (enhanced green fluorescent protein). Sarcoma cells were co-cultured or co-injected with bone marrow–derived MSCs for growth studies. Xenograft tumor models were established with STS lines in NOD/SCID/γ_c^null mice. To emulate a clinical scenario, subcutaneous tumors were treated with RT/surgery prior to MSC injection into the tumor bed. Local and distant tumor recurrence was studied using histology and bioluminescence imaging. Results. MSCs did not promote STS proliferation upon co-culture in vitro, which was consistent among MSCs from different donors. Co-injection of MSCs with sarcoma cells in mice exhibited no significant tumor-stimulating effect, compared with control mice injected with sarcoma cells alone. MSC administration after RT/surgery had no effect on local recurrence or metastasis of STS. Discussion. These studies are important for the establishment of a safety profile for MSC administration in patients with STS. Our data suggest that MSCs are safe in STS management after standard of care RT/surgery, which can be further investigated in early-phase clinical trials to also determine the efficacy of MSCs in reducing morbidity and to mitigate wound complications in these patients.     

Contrasting levels of genetic diversity between the historically rare orchid Cypripedium japonicum and the historically common orchid Cypripedium macranthos in South Korea

Many terrestrial orchids are historically rare and occur in small, spatially isolated populations. Theory predicts that such species will harbour low levels of genetic variation within populations and will exhibit a high degree of population genetic divergence, primarily as a result of genetic drift. If the origin of the present‐day populations is relatively recent from the same genetically depauperate source population, a complete lack of genetic differentiation between conspecific populations is expected. If a terrestrial orchid was historically common with moderate or high levels of genetic diversity, but has experienced more recent anthropogenic disturbance as a result of over‐collection, it would still exhibit initial levels of genetic variation within populations and a low degree of genetic divergence between populations. To test these predictions, we examined the genetic diversity in six populations (N = 131) of the historically and currently rare Cypripedium japonicum and in four populations (N = 94) of the historically common but now rare C. macranthos from South Korea. Fourteen putative allozyme loci resolved from eight enzyme systems revealed no variation either within or among populations of C. japonicum, which supports the first prediction. In contrast, populations of C. macranthos harboured high levels of genetic variation (mean percentage of polymorphic loci %P = 46.7; mean expected heterozygosity H_e = 0.185) and exhibited a low degree of population genetic divergence (G_ST = 0.059), supporting the second prediction. The lack of genetic variation both within and among conspecific populations of C. japonicum may suggest that populations originated from the same genetically depauperate ancestral population. The high levels of genetic diversity maintained in populations of C. macranthos suggest that the collection‐mediated decrease in the number of individuals is still too recent for long‐term effects on genetic variation. Based on current demographic and genetic data, in situ and ex situ conservation strategies should be provided to preserve genetic variation and to ensure the long‐term survival of the two species in the Korean Peninsula. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 119–129.