Correlative Light-Electron Microscopy (CLEM) and 3D Volume Imaging of Serial Block-Face Scanning Electron Microscopy (SBF-SEM) of Langerhans Islets

Correlative light-electron microscopy (CLEM) is a developing technique for combined analysis of immunostaining for various biological molecules coupled with investigations of ultrastructural features of individual cells within a large field of view. This study first introduces a method of CLEM imaging of the same endocrine cells of compact and diffuse Langerhans islets from human pancreatic tissue specimens. The method utilises serial sections obtained from Epon-embedded specimens fixed with glutaraldehyde and osmium tetroxide. Next, serial block-face imaging using scanning electron microscopy (SBF-SEM) is advanced to enable rapid and efficient acquisition of three-dimensional (3D) ultrastructural information from Langerhans islets of mouse pancreas corresponding to the CLEM images. Samples for SBF-SEM observations were postfixed with osmium and stained en bloc and embedded in conductive resins with ketjenblack significantly reduced the charging of samples during SBF-SEM imaging

APPLICATION OF SATELLITE MICROWAVE REMOTE SENSING DATA TO SIMULATE MIGRATION PATTERN OF ALBACORE TUNA

To simulate migration pattern of albacore tuna in the western North Pacific Ocean during the winter period, a kinesis model driven by high accuracy of sea surface temperature (SST) maps was used. The SST data were derived from the Tropical Rainfall Measuring Mission/TRMM Microwave Imager (TRMM/TMI). Simulations showed that albacore tuna aggregated in areas of thermal preference indicated by contour line of 20°C SST. Results are compared with empirical observation maps of albacore tuna fishing locations determined from longline fishing operation during the same time periods. Albacore tuna distributions along thermal fronts generating from Simulations were fairly consistent with fishing data especially during November-January, although seasonal variations in surface temperature ranges occupied suggest that additional oceanographic factors are involved particularly during February-March. Simulations and empirical data had similar temperature distributions at approximately 18-21°C and one-sample Kolmogorov-Smirnov test reinforced the result performance. These results suggest that kinesis model driven by satellite microwave remote sensing is one of effective mechanisms for describing migration pattern of tuna in the open ocean environment. Keywords: Kinesis model, Microwave remote sensing, SST, Albacore tuna, Migration patter

Chlorophyll specific growth rate and grazing mortality rate of phytoplankton in the shelf water of the Bering Sea in summer

Chlorophyll specific growth rate and grazing mortality rate due to microzooplankton were estimated based on the dilution methods, using surface waters collected at four stations in the continental shelf area of the Bering Sea in summer. Growth rates and grazing mortality rates of phytoplankton communities were ranged between 0.06d^ and 0.56d^ and between 0.04d^ to 0.33d^, respectively. The high growth rate seems to have resulted from continuous supply of nutrients caused by gentle stratification, which is a favorable condition of the water column for phytoplankton growth. Growth and grazing mortality rates were almost the same at one station, where the most typical summer concentration of chlorophyll a was observed (less than 1μgl^), suggesting that the major grazer seems to be microzooplankton in the Bering Sea shelf in summer. On the other hand, the lowest growth rate was obtained in near St. Laurence Island, where higher chlorophyll concentrations more than several μgl^ occurred. In this water passive sinking of cells seems to become one of controlling factor of phytoplankton abundance

Albacore (Thunnus alalunga) fishing ground in relation to oceanographic conditions in the western North Pacific Ocean using remotely sensed satellite data

Tuna remote sensingSatellite-based oceanographic data of sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC) and sea surface height anomaly (SSHA) together with catch data were used to investigate the relationship between albacore fishing ground and oceanographic conditions and also to predict potential habitats for albacore in the western North Pacific Ocean. Empirical cumulative distribution function (ECDF) and high catch data analyses were used to calculate preferred ranges of the three oceanographic conditions. Results indicated that highest catch per unit efforts (CPUEs) corresponded with areas of SST 18.5 - 21.5??C, SSC 0.2 - 0.4 mg m-3 and SSHA ???5.0 - 32.2 cm during winter period 1998-2000. We used these ranges to generate a simple prediction map for detecting potential fishing grounds. Statistically, to predict spatial patterns of potential albacore habitats, we applied a combined Generalized Additive Model (GAM)/Generalized Linear Model (GLM). To build our model, we first constructed GAM as an exploratory tool to identify the functional relationships between the environmental variables and CPUE, we then made parameters out of these relationships using GLM to generate a robust prediction tool. The areas of highest CPUEs predicted by the models were consistent with the potential habitats on the simple prediction map and observation data, suggesting that the dynamics of ocean eddies (November 1998 and 2000) and fronts (November 1999) may account for the spatial patterns of highest albacore catch rates predicted in the study area. The results also suggest that multi-spectrum satellite data can provide useful information to characterize and predict potential tuna habitats

Histological Study and LYVE-1 Immunolocalization of Mouse Mesenteric Lymph Nodes with “In Vivo Cryotechnique”

The “in vivo cryotechnique” (IVCT) is a powerful tool to directly freeze living animal organs in order to maintain biological components in frozen tissues, reflecting their native states. In this study, mesenteric lymph nodes of living mice were directly frozen with IVCT, and we did morphological studies and immunohistochemical analyses on a hyaluronic acid receptor, LYVE-1. In lymph nodes, widely open lymphatic sinuses were observed, and many lymphocytes adhered to inner endothelial cells along subcapsular sinuses. The LYVE-1 was clearly immunolocalized at inner endothelial cells of subcapsular sinuses, as well as those of medullary sinuses. Conventional pre-embedding electron microscopy also showed LYVE-1 immunolocalization along both the apical and basal sides of cell membranes of inner endothelial cells. By triple-immunostaining for LYVE-1, smooth muscle actin, and type IV collagen, the LYVE-1 was immunolocalized only in the inner endothelial cells, but not in outer ones which were surrounded by collagen matrix and smooth muscle cells. Thus, the functional morphology of lymph nodes in vivo was demonstrated and LYVE-1 immunolocalization in inner endothelial cells of subcapsular sinuses suggests hyaluronic acid incorporation into lymph node parenchyma

Distribution of phytoplankton abundance and physical properties on the southeastern shelf of the Bering Sea in summer

Oceanographic structure, nutrient concentration, and chlorophyll a concentration were surveyed from 55°N to 59°N along 166°W on the southeastern shelf of the Bering Sea during mid to late July of 1994,1995,and 1996. The present results show a consistent trend that, in every year, high chlorophyll a concentration occurred in the outer shelf domain around 55°00\u27N, as well as the coastal shelf domain, and that the concentrations were usually low in the central shelf domain although large yearly variation occurred. The high phytoplankton abundance in the southern outer shelf domain related to relatively high salinity water, which contained more nitrate than the central shelf domain water. It is suggested that the high abundance is maintained by a continuous supply of nutrients caused by interaction between the ocean current from the open water of the North Pacific and the bottom topography in the vicinity of Unimak Pass. On the other hand, alternative high chlorophyll a stock was observed in the coastal shelf domain, where the sea floor depth was about 40m and vertically homogenous water properties occurred. This suggests that the nutrient supply from the bottom maintains the high phytoplankton abundance. In the central shelf domain, chlorophyll a concentrations less than 1.0μg l^ were usually observed between 55°30\u27N and 58°30\u27N in 1995 and 1996. In 1994,however, chlorophyll a concentrations of 1.0 to 2.0 μg l^ were widely distributed. The slightly high concentrations coincided with a weak pycnocline and occurrence of cold bottom water, which contained high nitrate. It is suggested that phytoplankton abundance may be low when the pycnocline is well developed or the cold bottom water does not transport a large amount of nutrients in the central shelf domain of the southeastern Bering Sea

Immunohistochemical Distribution of Serum Proteins in Living Mouse Heart with In Vivo Cryotechnique

In vivo cryotechnique (IVCT), which immediately cryofixes target organs in situ, was used to clarify the morphological features of beating heart tissue of living mice. IVCT was performed for diastolic heart tissue under the condition of monitoring with electrocardiogram (ECG). Other mouse hearts were prepared with conventional perfusion-fixation (PF-DH) or immersion-fixation followed by dehydration (IM-DH), and quick-freezing of resected heart tissues (FQF). Immunolocalizations of albumin, immunoglobulin G1 (IgG1), intravenously injected bovine serum albumin (BSA), and connexin 43 were examined after different intervals of BSA injection. In the case of IVCT, the exact stop time of beating mouse hearts was recorded by ECG, and open blood vessels with flowing erythrocytes were observed with less artificial tissue shrinkage than with conventional preparation methods. Both albumin and BSA were well preserved in intercalated discs and t-tubules of cardiomyocytes in addition to blood vessels and interstitial matrices. IgG1 was immunolocalized in interstitial matrices of heart tissues in addition to their blood vessels. At 4 hr after BSA injection, it was immunolocalized in the intercalated discs of cardiomyocytes and lost later at 8 hr. IVCT should prove to be more useful for the morphofunctional examination of dynamically changing heart tissue than conventional preparation methods

Japan Tsunami Current Flows Observed by HF Radars on Two Continents

Quantitative real-time observations of a tsunami have been limited to deep-water, pressure-sensor observations of changes in the sea surface elevation and observations of sea level fluctuations at the coast, which are essentially point measurements. Constrained by these data, models have been used for predictions and warning of the arrival of a tsunami, but to date no detailed verification of flow patterns nor area measurements have been possible. Here we present unique HF-radar area observations of the tsunami signal seen in current velocities as the wave train approaches the coast. Networks of coastal HF-radars are now routinely observing surface currents in many countries and we report clear results from five HF radar sites spanning a distance of 8,200 km on two continents following the magnitude 9.0 earthquake off Sendai, Japan, on 11 March 2011. We confirm the tsunami signal with three different methodologies and compare the currents observed with coastal sea level fluctuations at tide gauges. The distance offshore at which the tsunami can be detected, and hence the warning time provided, depends on the bathymetry: the wider the shallow continental shelf, the greater this time. Data from these and other radars around the Pacific rim can be used to further develop radar as an important tool to aid in tsunami observation and warning as well as post-processing comparisons between observation and model predictions