Evaluation of Mn and Fe in coral skeletons (Porites spp.) as proxies for sediment loading and reconstruction of 50 yrs of land use on Ishigaki Island,Japan

Manganese (Mn) and iron (Fe) concentrations were measured in coral skeletons (Porites spp.) collected from the Todoroki River on Ishigaki Island, Japan, to reconstruct the history of land use in the river catchment area. We prepared (1) five bulk samples to investigate the present spatial distribution and (2) micro-samples from two long cores to study the temporal variability of sediment loading from the Todoroki River. The existing state of the elements Mn and Fe in bulk coral skeleton samples was examined by a chemical cleaning experiment. The results of the experiment suggested that Fe was not incorporated into the crystal lattice of the coral skeleton but that Mn was incorporated, as previously reported. The bulk sample data, with and without chemical cleaning, indicated that the spatial distribution of both elements in corals collected along a sampling line from the river mouth toward the reef crest was complex and most likely reflected salinity changes and the amount of suspended particulate matter. The temporal variation of Mn and Fe, in particular the variation of baseline/background levels, mainly reflected the history of land development on Ishigaki Island. In addition, Mn showed clear seasonal variability that appeared to be controlled by a combination of temperature, primary productivity, and precipitation. The results of the present study suggest that Mn may be a useful proxy for river discharge or biological activity depending on local marine conditions, if the specific behavior of Mn at the coral growth site is known.     

Induction of Macrophage-Like Immunosuppressive Cells from Mouse ES Cells That Contribute to Prolong Allogeneic Graft Survival

Recent progress in regenerative medicine has enabled the utilization of pluripotent stem cells (PSCs) such as embryonic stem cells (ESCs) as a donor resource for transplantation. However, immune suppression is still needed when the donor-recipient combination is allogeneic. Protection of ESCs-derived grafts from host immune response might be achieved thought the utilization of immunosuppressive cells generated from ESCs. In the present study, we show that a certain fraction of immunosuppressive cells can be generated from ESCs and help to suppress immune response against allogeneic grafts. ESCs-derived suppressor cells (ES-SCs) resembled macrophages in terms of cell surface molecule and gene expressions. Furthermore, gene expression analysis including microarray showed that ES-SCs have M1/M2 hybrid phenotype with high expression of genes correlated to immunosuppression of T cell response. Indeed, ES-SCs were effective to block allogeneic T cell proliferation in a nitric oxide-dependent manner, and prolonged the survival of ESCs-derived embryoid bodies or cardiomyocytes grafts transplanted into mouse kidney capsule. Thus, we consider the potential use of these ESCs-derived macrophage-like immunosuppressive cells as cellular therapies to promote long-term graft survival in future therapies.     

The Vitamin D Analogue ED71 but Not 1,25(OH)2D3 Targets HIF1α Protein in Osteoclasts

Although both an active form of the vitamin D metabolite, 1,25(OH)₂D₃, and the vitamin D analogue, ED71 have been used to treat osteoporosis, anti-bone resorbing activity is reportedly seen only in ED71- but not in 1,25(OH)₂D₃ -treated patients. In addition, how ED71 inhibits osteoclast activity in patients has not been fully characterized. Recently, HIF1α expression in osteoclasts was demonstrated to be required for development of post-menopausal osteoporosis. Here we show that ED71 but not 1,25(OH)₂D₃, suppress HIF1α protein expression in osteoclasts in vitro. We found that 1,25(OH)₂D₃ or ED71 function in osteoclasts requires the vitamin D receptor (VDR). ED71 was significantly less effective in inhibiting M-CSF and RANKL-stimulated osteoclastogenesis than was 1,25(OH)₂D₃ in vitro. Downregulation of c-Fos protein and induction of Ifnβ mRNA in osteoclasts, both of which reportedly block osteoclastogenesis induced by 1,25(OH)₂D₃ in vitro, were both significantly higher following treatment with 1,25(OH)₂D₃ than with ED71. Thus, suppression of HIF1α protein activity in osteoclasts in vitro, which is more efficiently achieved by ED71 rather than by 1,25(OH)₂D₃, could be a reliable read-out in either developing or screening reagents targeting osteoporosis.     

Transient infiltration of neutrophils into the thymus following whole-body X-ray irradiation in IL-10 knockout mice

IL-10 is known to suppress the inflammatory responses in a variety of experimental models. Because we previously found that whole-body X-irradiation causes massive apoptosis in the thymus and transient infiltration of neutrophils, in this study, we examined whether or not IL-10 is involved in the regulation of neutrophil infiltration upon whole-body X-ray irradiation using IL-10 knockout mice. Although IL-10 was induced in the thymus on whole-body X-ray irradiation, apoptosis of thymocytes, neutrophil infiltration, and MIP-2 and KC production in the thymus were not affected by an IL-10 deficiency. Coculturing of bone marrow-derived macrophages with late apoptotic cells caused MIP-2 production, which was also not affected by an IL-10 deficiency. These results suggest the uniqueness of the inflammatory response induced by whole-body X-ray irradiation, which does not seem to be regulated by IL-10.     

Single bacterial cell detection using a mutant luciferase

Previously, we constructed a genetically modified luciferase of Photinus pyralis that generates more than 10-fold higher luminescence intensity than the wild-type enzyme. In this study, we demonstrate that this modified luciferase enables us to detect ATP at 10⁻¹⁸ mol, which is almost equal to the quantity contained in a single bacterial cell. Consequently,we have been able to detect bacterial contamination in samples as low as one colony-forming unit (c.f.u.) for both Escherichia coli and Bacillus subtilis.     

Improving the interpretability of climate landscape metrics: An ecological risk analysis of Japan's Marine Protected Areas

Conservation efforts strive to protect significant swaths of terrestrial, freshwater and marine ecosystems from a range of threats. As climate change becomes an increasing concern, these efforts must take into account how resilient‐protected spaces will be in the face of future drivers of change such as warming temperatures. Climate landscape metrics, which signal the spatial magnitude and direction of climate change, support a convenient initial assessment of potential threats to and opportunities within ecosystems to inform conservation and policy efforts where biological data are not available. However, inference of risk from purely physical climatic changes is difficult unless set in a meaningful ecological context. Here, we aim to establish this context using historical climatic variability, as a proxy for local adaptation by resident biota, to identify areas where current local climate conditions will remain extant and future regional climate analogues will emerge. This information is then related to the processes governing species’ climate‐driven range edge dynamics, differentiating changes in local climate conditions as promoters of species range contractions from those in neighbouring locations facilitating range expansions. We applied this approach to assess the future climatic stability and connectivity of Japanese waters and its network of marine protected areas (MPAs). We find 88% of Japanese waters transitioning to climates outside their historical variability bounds by 2035, resulting in large reductions in the amount of available climatic space potentially promoting widespread range contractions and expansions. Areas of high connectivity, where shifting climates converge, are present along sections of the coast facilitated by the strong latitudinal gradient of the Japanese archipelago and its ocean current system. While these areas overlap significantly with areas currently under significant anthropogenic pressures, they also include much of the MPA network that may provide stepping‐stone protection for species that must shift their distribution because of climate change.     

Projecting the impacts of rising seawater temperatures on the distribution of seaweeds around Japan under multiple climate change scenarios

Seaweed beds play a key role in providing essential habitats and energy to coastal areas, with enhancements in productivity and biodiversity and benefits to human societies. However, the spatial extent of seaweed beds around Japan has decreased due to coastal reclamation, water quality changes, rising water temperatures, and heavy grazing by herbivores. Using monthly mean sea surface temperature (SST) data from 1960 to 2099 and SST‐based indices, we quantitatively evaluated the effects of warming seawater on the spatial extent of suitable versus unsuitable habitats for temperate seaweed Ecklonia cava, which is predominantly found in southern Japanese waters. SST data were generated using the most recent multiple climate projection models and emission scenarios (the Representative Concentration Pathways or RCPs) used in the Coupled Model Intercomparison Project phase 5 (CMIP5). In addition, grazing by Siganus fuscescens, an herbivorous fish, was evaluated under the four RCP simulations. Our results suggest that continued warming may drive a poleward shift in the distribution of E. cava, with large differences depending on the climate scenario. For the lowest emission scenario (RCP2.6), most existing E. cava populations would not be impacted by seawater warming directly but would be adversely affected by intensified year‐round grazing. For the highest emission scenario (RCP8.5), previously suitable habitats throughout coastal Japan would become untenable for E. cava by the 2090s, due to both high‐temperature stress and intensified grazing. Our projections highlight the importance of not only mitigating regional warming due to climate change, but also protecting E. cava from herbivores to conserve suitable habitats on the Japanese coast.