Environmental factors determining the distribution of highland plants at low-altitude algific talus sites

Algific talus is a micro-scale habitat type where highland plants (subalpine and alpine species) are found, disjunct from their typical range, in lowland forests. On algific talus, cold airflows from the interstices between talus fragments create a local microclimate colder than surrounding forests. Despite of the widely-known occurrence of unique vegetation on algific talus, critical environmental factors determining the distribution of highland species in this habitat type are unclear. In order to reveal the environmental factors enabling highland species to inhabit algific talus, we investigated the vegetation and environments of 26 algific talus sites and four reference (non-algific talus) sites in Hokkaido, northern Japan. Several algific talus sites were dominated by highland species, while some algific talus sites and all non-algific talus sites were dominated by lowland species. Community analysis based on detrended correspondence analysis (DCA) and canonical corresponding analysis (CCA) revealed that the algific talus sites dominated by highland species had lower ground temperature, more acidic soil, larger canopy openness, and less diverse vegetation than the sites dominated by lowland species. Highland plants might be maintained under conditions stressful for lowland plants, resulting in less competitive situation. Generalized linear models (GLM), used to evaluate the response of individual highland species to environmental factors, revealed that preferable environmental conditions for highland plants are highly species specific. These results indicate that the maintenance of diverse environments is crucial for the conservation of the unique vegetation and local populations of highland species in algific talus areas.     

Production and characterization of transgenic mice harboring mutant human UMOD gene

Familial juvenile hyperuricemic nephropathy is caused by mutations in the UMOD gene encoding uromodulin. A transgenic mouse model was developed by introducing a human mutant UMOD (C148W) cDNA under control of the mouse umod promoter. Uromodulin accumulation was observed in the thick ascending limb cells in the kidney of transgenic mice. However, the urinary excretion of uromodulin in transgenic mice did not decrease and LC-MS/MS analysis indicated it was of mouse origin. Moreover, the creatinine clearance was not different between wildtype and transgenic animals. Consequently, the onset of the disease was not observed in transgenic mice until 24 weeks of age.     

A method for the synthesis of an oseltamivir PET tracer

A protocol applicable for the synthesis of an oseltamivir positron emission tomography (PET) tracer was developed. Acetylation of amine 3 with CH(3)COCl, followed by deprotection and aqueous workup, produced oseltamivir 4 from 3 within 10 min. The obtained 4 was sufficiently pure for PET studies. This method can be extended to PET tracer synthesis using CH(3)(11)COCl.     

Auxin Response in Arabidopsis under Cold Stress: Underlying Molecular Mechanisms

To understand the mechanistic basis of cold temperature stress and the role of the auxin response, we characterized root growth and gravity response of Arabidopsis thaliana after cold stress, finding that 8 to 12 h at 4°C inhibited root growth and gravity response by ∼50%. The auxin-signaling mutants axr1 and tir1, which show a reduced gravity response, responded to cold treatment like the wild type, suggesting that cold stress affects auxin transport rather than auxin signaling. Consistently, expression analyses of an auxin-responsive marker, IAA2-GUS, and a direct transport assay confirmed that cold inhibits root basipetal (shootward) auxin transport. Microscopy of living cells revealed that trafficking of the auxin efflux carrier PIN2, which acts in basipetal auxin transport, was dramatically reduced by cold. The lateral relocalization of PIN3, which has been suggested to mediate the early phase of root gravity response, was also inhibited by cold stress. Additionally, cold differentially affected various protein trafficking pathways. Furthermore, the inhibition of protein trafficking by cold is independent of cellular actin organization and membrane fluidity. Taken together, these results suggest that the effect of cold stress on auxin is linked to the inhibition of intracellular trafficking of auxin efflux carriers.     

Improvement of isoflavone aglycones production using β-glucosidase secretory produced in recombinant Aspergillus oryzae

β-Glucosidase (BGL1) from Aspergillus oryzae was efficiently produced in recombinant A. oryzae using sodM promoter-mediated expression system. The yield of BGL1 was 960 mg/l in liquid culture, which is 20-fold higher than the yield of BGL1 produced using the yeast Saccharomyces cerevisiae. Recombinant BGL1 converted isoflavone glycosides into isoflavone aglycones more efficiently than β-glucosidase from almond. In addition, BGL1 produced isoflavone aglycones even in the presence of the insoluble form of isoflavone glycosides.     

Effects of fine sediment accumulation on the redd environment and the survival rate of masu salmon (Oncorhynchus masou) embryos

In recent years, fine sediment, produced by run-off associated with forestry activity and agricultural development that accumulates on riverbeds, has exerted a deleterious influence on lotic ecosystems. This study examined the Oroennukibetsu River, a tributary of the Nukibetsu River, which has been affected by high loads of suspended sediments. Effects of accumulation of fine sediment on the survival rate of masu salmon embryo and also on the redd environment (permeability and intragravel dissolved oxygen concentration) were quantified through a field experiment. Results show that the interchange of DO between intragravel and surface water was not affected directly by permeability or the accumulated fine sediment and that intragravel flow rates can be an important factor controlling embryo survival. A decrease in permeability associated with accumulation of fine sediment lowered the survival rate of embryos by suffocation because the flux of DO that should be supplied to the embryo was severely limited. This situation might be created by the combined effects of an accumulation of fine sediment on the redd and a low DO concentration in the surface water because the DO concentration almost coincided with the intragravel DO.     

Activation of nucleotide‐binding domain‐like receptor containing protein 3 inflammasome in dendritic cells and macrophages by Streptococcus sanguinis

Streptococcus sanguinis is frequently isolated from the blood of patients with infective endocarditis and contributes to the pathology of this disease through induction of interleukin (IL)‐1β responsible for the development of the disease. However, the mechanism of IL‐1β induction remains unknown. In this study, S. sanguinis activated a murine dendritic cell (DC) to induce IL‐1β and this activity was attenuated by silencing the mRNAs of nucleotide‐binding domain‐like receptor containing protein 3 (NLRP3) and caspase‐1. S. sanguinis induced IL‐1β production in murine bone marrow‐derived macrophage, but this activity was significantly reduced in bone marrow‐derived macrophages from NLRP3‐, apoptosis‐associated speck‐like protein containing a caspase‐recruitment domain‐, and caspase‐1‐deficient mice. DC phagocytosed S. sanguinis cells, followed by the release of adenosine triphosphate (ATP). The ATP‐degradating enzyme attenuated the release of ATP and IL‐1β. The inhibitors for ATP receptor reduced IL‐1β release in DC. These results strongly suggest that S. sanguinis has the activity to induce IL‐1β through the NLRP3 inflammasome in macrophage and DC and interaction of purinergic receptors with ATP released is involved in expression of the activity.     

Flavone-catalyzed apoptosis in Scutellaria baicalensis

In response to mechanical damage, roots of Scutellaria baicalensis undergo cell death within 24 h. The flavone baicalein was identified as the factor regulating apoptosis in the damaged roots of S. baicalensis. Plant apoptosis is known to be triggered by oxidative damage of DNA through oxidative bursts, whereas baicalein causes apoptosis in Scutellaria cells by a copper-dependent oxidation of nuclear DNA without inducing an oxidative burst. S. baicalensis possesses an interesting system for quickly producing this apoptosis-inducing flavone in its cells. Intact Scutellaria cells contain little baicalein but store a large amount of baicalin (baicalein 7-O-β-D-glucuronide). Stress treatment of Scutellaria cells immediately initiates hydrolysis of baicalin by endogenous β-glucuronidase, and the resulting baicalein is immediately translocated to the nucleus, leading to apoptosis. Thus, S. baicalensis possesses a unique apoptosis-inducing system that is linked with metabolism of baicalin.