Evaluation of carrying capacity in coastal waters

Abstracts of 2nd UNU-ORI joint international workshop for marine environment第2回海洋環境国際ワークショップ講演要

Surface nutrient regime and bottom hypoxia in Manila Bay during the southwest monsoon

We e amined the surface nutrient regime and hypo ia in Manila Bay, Philippines, during the southwest monsoon along a transect from off Limay, Bataan Peninsula, to Metro Ma nila. The water column showed stratification, with warm, less saline water in the top 10 meters overlying cold, saline bottom water. Hypo ia was present in the bottom waters along the entire transect, and ano ic conditions were observed off Manila. Ammonium concentrations ranged from 6.7 to 40.2 µM, e ceeding those of nitrate and nitrite, both of which were nearly depleted at almost all stations e cept off-Manila, with levels below 0.1 µM. Phosphate varied from 0.1 to 1.9 µM, resulting in a stoichiometrically nitrogen-rich condition at the surface, with N:P ratios ranging from 17.1 to 149.7 and an average of 37.4. This is in contrast to the phosphate-rich con ditions reported during the northeast monsoon period. A plume with high nutrient concentrations and high chlorophyll a was observed off Manila, indicating freshwater inflow from sewage and the Pasig River. Diatoms, including the Skeletonema costatum comple and Chaetoceros spp., were abundant, and these eutrophic conditions likely favored the occurrence of green Noctiluca, while it was not observed during our study.departmental bulletin pape

\u3ci\u3eIn vitro\u3c/i\u3e assembly of apophytochrome and apophytochrome deletion mutants expressed in yeast with phycocyanobilin

Recombinant pea type I phytochrome apoprotein expressed in yeast is shown to assemble in vitro with phycocyanobilin to produce a photoreversible phytochromelike adduct. As an initial investigation of the amino acid sequence requirements for chromophore incorporation, three phyA gene product deletion mutants were produced in yeast. Truncation of the N-terminal tail to residue 46 demonstrates that this region is not critical to bilin attachment, but a deletion mutant lacking 222 amino acids from the N terminus failed to yield holophytochrome in vitro, under the same conditions. A mutant comprising a deletion of the C terminus to residue 548 showed bilin incorporation and red/far-red photoreversibility, indicating that bilin-apophytochrome assembly still occurred even when the entire C-terminal domain was truncated

Seasonal variations in cell abundance of Noctiluca scintillans in the coastal waters off Chonburi Province, the upper Gulf of Thailand

Seasonal variations in cell abundance of Noctiluca scintillans was studied from June 2003 to November 2004 in the coastal waters off Chonburi Province, the upper gulf of Thailand. Eight stations from Bangpakong River mouth to Angsila were designed to cover the area where red tides often occurred and were under the influence of Bangpakong River. Numerical abundance was analyzed in relation with some environmental parameters. A total of 9 N. scintillans red tides, 7 Ceratium furca red tides and 4 diatom red tides were found in this study. Noctiluca and Ceratium red tides were often found when salinity was in the range of 22 to 33psu. and 12 to 27psu., respectively. Those red tides were not associated with apparent negative effects to marine animals. N. scintillans cells could be observed almost all year round at offshore stations where the water depth was more than 10 meters except strong wind periods, suggesting that Noctiluca in coastal waters were supplied by cells from offshore stations. In contrast, no consistent pattern was observed in the distribution of N. scintillans in coastal waters, in particular near the river mouth. Only the relationship between phosphate concentrations and cell densities of Noctiluca has been found statistically significant. However, the high cell densities of both Noctiluca and Ceratium were often observed in the rainy season, especially on the calm day after heavy rain. These observations suggested that the red tides of those two species in coastal waters were growth response to the influence of freshwater run off from Bangpakong River

Photosynthesis-irradiance relationship of phytoplankton and primary production in the vicinity of kuroshio warm core ring in spring

The light-saturated maximum value (P B max ) and initial slope (α) of the photosynthesisirradiance (P-E) curve were examined in a warm streamer, a cold streamer and a warm core ring off the Sanriku area in the subarctic western North Pacific Ocean during an ADEOS/OCTS Sanriku field campaign in early May 1997. Both P B max and α were within the ranges of temperate populations. A regional difference was apparent in P B max : populations in the warm streamer tended to show higher value ranging between 1.92 and 4.74 mgC (mgChl a) -1 h -1 than those in the cold streamer and the warm core ring (1.35-2.87 mgC (mgChl a) -1 h -1 ). A depth variation was also observed in α in both the warm streamer and the warm core ring: shallow populations tended to have lower α than deep populations. The depth variations in both P B max and α resulted in a lower light intensity of the light saturation in a deeper population than that of a shallower one. These depthrelated variations in the P-E parameters were likely a manifestation of "shade-adaptation" of photosynthesis. Photoinhibition was not observed over in situ surface light intensity varying below ca 1600 µmol photon m -2 s -1 . Water-column primary productivity was biooptically estimated to be 233 to 949 mgC m -2 d -1 using vertical distributions of the P-E parameters, chlorophyll a, phytoplankton light absorption and underwater irradiance. Applicability of surface data sets for estimation of water-column productivity is discussed

Increased Rac1 activity and Pak1 overexpression are associated with lymphovascular invasion and lymph node metastasis of upper urinary tract cancer

<p>Abstract</p> <p>Background</p> <p>Lymphovascular invasion (LVI) and lymph node metastasis are conventional pathological factors associated with an unfavorable prognosis of urothelial carcinoma of the upper urinary tract (UC-UUT), but little is known about the molecular mechanisms underlying LVI and nodal metastasis in this disease. Rac1 small GTPase (Rac1) is essential for tumor metastasis. Activated GTP-bound Rac1 (Rac1 activity) plays a key role in activating downstream effectors known as Pak (21-activated kinase), which are key regulators of cytoskeletal remolding, cell motility, and cell proliferation, and thus have a role in both carcinogenesis and tumor invasion.</p> <p>Methods</p> <p>We analyzed Rac1 activity and Pak1 protein expression in matched sets of tumor tissue, non-tumor tissue, and metastatic lymph node tissue obtained from the surgical specimens of 108 Japanese patients with UC-UUT.</p> <p>Results</p> <p>Rac1 activity and Pak1 protein levels were higher in tumor tissue and metastatic lymph node tissue than in non-tumor tissue (both <it>P </it>< 0.0001). A high level of Rac1 activity and Pak1 protein expression in the primary tumor was related to poor differentiation (<it>P </it>< 0.05), muscle invasion (<it>P </it>< 0.01), LVI (<it>P </it>< 0.0001), and lymph node metastasis (<it>P </it>< 0.0001). Kaplan-Meier survival analysis showed that an increase of Rac1 activity and Pak1 protein was associated with a shorter disease-free survival time (<it>P </it>< 0.01) and shorter overall survival (<it>P </it>< 0.001). Cox proportional hazards analysis revealed that high Rac1 activity, Pak1 protein expression and LVI were independent prognostic factors for shorter overall and disease-free survival times (<it>P </it>< 0.01) on univariate analysis, although only Pak1 and LVI had an influence (<it>P </it>< 0.05) according to multivariate analysis.</p> <p>Conclusions</p> <p>These findings suggest that Rac1 activity and Pak1 are involved in LVI and lymph node metastasis of UC-UUT, and may be prognostic markers for this disease.</p

Elevation of Bombina variegata peptide 8 in mice with collagen-induced arthritis

<p>Abstract</p> <p>Background</p> <p><it>Bombina variegate </it>peptide 8 (Bv8) is a small protein secreted by frog skin. Recently it has been shown to contribute to tumor angiogenesis in mouse model. The purpose of this study was to investigate Bv8 in mice with type II collagen-induced arthritis (CIA).</p> <p>Methods</p> <p>We induced CIA in male DBA/1J mice. The severity of arthritis was evaluated based on an arthritis score. RNA was extracted from the joint, and examined for Bv8 mRNA expression by RT-PCR and real-time RT-PCR. Synovial tissue and bone marrow were immunohistochemically examined using anti-Bv8 antibody.</p> <p>Results</p> <p>The level of Bv8 mRNA expression in the joint was below the detection limit in the control group, but was elevated in the CIA group, and was correlated with the arthritis score. In addition, an increase in Bv8-positive cells was observed in the synovium and bone marrow in the CIA group.</p> <p>Conclusion</p> <p>Bv8 was elevated in the synovium and bone marrow of CIA mice, suggesting that Bv8 plays an important role in the pathogenesis of arthritis.</p

Biogeochemical controls of surface ocean phosphate

Surface ocean phosphate is commonly below the standard analytical detection limits, leading to an incomplete picture of the global variation and biogeochemical role of phosphate. A global compilation of phosphate measured using high-sensitivity methods revealed several previously unrecognized low-phosphate areas and clear regional differences. Both observational climatologies and Earth system models (ESMs) systematically overestimated surface phosphate. Furthermore, ESMs misrepresented the relationships between phosphate, phytoplankton biomass, and primary productivity. Atmospheric iron input and nitrogen fixation are known important controls on surface phosphate, but model simulations showed that differences in the iron-to-macronutrient ratio in the vertical nutrient supply and surface lateral transport are additional drivers of phosphate concentrations. Our study demonstrates the importance of accurately quantifying nutrients for understanding the regulation of ocean ecosystems and biogeochemistry now and under future climate conditions