New methods and allelopathic considerations of riparian buffer zones using Phragmites australis (Cav.) Trin.

Recently, the riparian buffer zone using Phragmites australis (Cav.) Trin. has frequently been installed in the ecotone, and young shoots of P. australis have been produced worldwide using seeds and/or rhizomes. However, the expenditures of labor, time, and money related to this technique have been enormous. In this paper, therefore, a new method which enables the reduction of the above-mentioned expenditure is developed and proposed. Using this method, we were able to install an area where P. australis flourished without the production of young shoots, by simply placing segments of P. australis culms by the water, and were able to reduce the above-mentioned usual expenditure. On the other hand, hydrophytes such as Scirpus tabernaemontani Gmel., Zizania latifolia Turcz. and Typha latifolia L. have frequently been planted with P. australis as a riparian buffer zone material. In this study, therefore, the care required in the mix planting of the above-mentioned four hydrophytes was also examined on the basis of the allelopathic potential of the interspecies. As a result, the allelopathic inhibition of root elongation was observed between the interspecies. Therefore a sufficient planting interval is required in order to ensure the elongation of the roots of the above-mentioned hydrophytes in the case of mix planting.     

Glial fibrillary acidic protein is greatly modified by oxidative stress in aceruloplasminemia brain

Aceruloplasminemia is an autosomal recessive disorder of iron metabolism caused by mutations in the ceruloplasmin (Cp) gene. The neuropathological hallmark of this disease is intracellular iron overload, which is thought to lead to neuronal cell death through increased oxidative stress. We evaluated and characterized protein oxidation in the brain of a patient with this disease. The protein carbonyl content in the cerebral cortex of the patient was elevated compared to controls. Furthermore, peptide mass fingerprinting and partial amino acid sequencing identified glial fibrillary acidic protein (GFAP) as the major carbonylated protein in the cerebral cortex of the patient. In conjunction with the facts that Cp mainly localizes to astrocytes in the central nervous system and that astrocytes are loaded with much more iron than neurons in the cerebral cortex, our findings indicate that Cp deficiency may primarily damage astrocytes. We speculate that the dysfunction of astrocytes may be causatively related to neuronal cell loss in aceruloplasminemia.     

Effects of food distribution on the habitat usage of a female brown bear Ursus arctos yesoensis in a beech-forest zone of northernmost Japan

The habitat usage of a female brown bear, Ursus arctos yesoensis L., was studied in relation to the distribution of food plants in a beech-forest zone of Hokkaido, Japan. The bears habitat usage was correlated with the distribution of the plant Angelica ursina (Rupt.) Maxim. in summer. In spring the bear preferred Petasites japonicus (Sieb. et Zucc.) Maxim. and Heracleum dulce Fisch., whose abundance did not differ significantly between Sasa–beech forests and coniferous forests. However, the bear spent more time in coniferous forests where its den site was located. In autumn, this bear preferred the plant Actinidia arguta (Sieb. et Zucc.) Planch. ex Mig., which was abundant in maple–linden forests, however, the bears habitat usage was not correlated with the distribution of A. arguta because it frequently returned to an overlapping area where A. arguta was scarce. Thus, the bears habitat usage depended on food distribution as well as on the location of the den site and the behavioral core area.     

Telomere-bound TRF1 and TRF2 stall the replication fork at telomeric repeats

Vertebrate telomeres consist of tandem repeats of T₂AG₃ and associated proteins including the telomeric DNA-binding proteins, TRF1 and TRF2. It has been proposed that telomeres assume two interswitchable states, the open state that is accessible to various trans-acting factors and the closed state that excludes those factors. TRF1 and TRF2 are believed to promote the formation of the closed state. However, little is known about how those two states influence DNA replication. We analyzed the effects of TRF1 and TRF2 on telomeric replication both in vitro and in vivo. By exploiting the in vitro replication system of linear SV40 DNA, we found that telomeric repeats are a poor replication template. Moreover, the addition of recombinant TRF1 and TRF2 significantly stalled the replication fork progression at telomeric repeats. When TRF1 was overexpressed in HeLa cells, cells with 4N DNA content were accumulated. Furthermore, cytological analyses revealed that the replication focus overlapped with telomere signals at a significantly higher frequency in TRF1-overexpressing cells than in control cells. The results suggest that TRF1 and TRF2 exert inhibitory effects on replication fork progression.     

Elevated CO2 enhances the growth of hybrid larch F1 (Larix gmelinii var. japonica × L. kaempferi) seedlings and changes its biomass allocation

Key message

Elevated CO ₂ enhances the photosynthesis and growth of hybrid larch F ₁ seedlings. However, elevated CO ₂ -induced change of tree shape may have risk to the other environmental stresses.

Abstract

The hybrid larch F₁ (Larix gmelinii var. japonica × L. kaempferi) is one of the most promising species for timber production as well as absorption of atmospheric CO₂. To assess the ability of this species in the future high CO₂ environment, we investigated the growth and photosynthetic response of hybrid larch F₁ seedlings to elevated CO₂ concentration. Three-year-old seedlings of hybrid larch F₁ were grown on fertile brown forest soil or infertile volcanic ash soil, and exposed to 500 μmol mol^?1 CO₂ in a free-air CO₂ enrichment system located in northern Japan for two growing seasons. Regardless of soil type, the exposure to elevated CO₂ did not affect photosynthetic traits in the first and second growing seasons; a higher net photosynthetic rate was maintained under elevated CO₂. Growth of the seedlings under elevated CO₂ was greater than that under ambient CO₂. We found that elevated CO₂ induced a change in the shape of seedlings: small roots, slender-shaped stems and long-shoots. These results suggest that elevated CO₂ stimulates the growth of hybrid larch F₁, although the change in tree shape may increase the risk of other stresses, such as strong winds, heavy snow, and nutrient deficiency.     

Suppression of SOCS3 expression in the pancreatic beta-cell leads to resistance to type 1 diabetes

Type 1 diabetes results from the selective destruction of insulin-producing pancreatic beta-cells during islet inflammation, which involves inflammatory cytokines and free radicals. However, mechanisms for protecting beta-cells from destruction have not been clarified. In this study, we define the role of SOCS3 on beta-cell destruction using beta-cell-specific SOCS3-conditional knockout (cKO) mice. The beta-cell-specific SOCS3-deficient mice were resistant to the development of diabetes caused by streptozotocin (STZ), a genotoxic methylating agent, which has been used to trigger beta-cell destruction. The islets from cKO mice demonstrated hyperactivation of STAT3 and higher induction of Bcl-xL than did islets from WT mice, and SOCS3-deficient beta-cells were more resistant to apoptosis induced by STZ in vitro than were WT beta-cells. These results suggest that enhanced STAT3 signaling protects beta-cells from destruction induced by a genotoxic stress and that STAT3/SOCS3 can be a potential therapeutic target for the treatment of type 1 diabetes.     

Identification of casein kinase-1 phosphorylation sites on TDP-43

TAR DNA-binding protein of 43 kDa (TDP-43) is deposited as hyperphosphorylated cytoplasmic and intranuclear inclusions in brains of patients with frontotemporal lobar degeneration with ubiquitinated inclusions and amyotrophic lateral sclerosis. In this study, we identified 29 phosphorylation sites on recombinant TDP-43 that are phosphorylated by casein kinase-1 (CK1). Interestingly, 18 of them were located in the C-terminal glycine-rich region of TDP-43. Our results indicate that CK1-mediated phosphorylation may play a role in the pathogenesis of these diseases.