Degradation of outer membrane proteins of <Emphasis Type="Italic">Synechococcus</Emphasis> sp. <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in situ</Emphasis>     

Tatsuo?Miyoshi  Satoru?SuzukiEmail author 《Journal of Oceanography》2004,60(5):825-833

To examine the possibility that outer membrane proteins (OMP) of Synechococcus sp. remain in seawater, we investigated the stability of OMPs in vitro and in situ. Some fractions prepared from Synechococcus sp. CSIRO-94 were treated with trypsin and proteinase K. Four tightly bound OMPs were separated from Synechococcus. We designated the two major OMPs of 52 kDa and 48 kDa as Omp52Sy and Omp48Sy, respectively. Degradation of the OMP in natural seawater was monitored in microcosms to which intact Synechococcus cells and outer membrane (OM) were added. Omp52Sy and Omp48Sy were the most stable against trypsin and proteinase K among the OMPs when they were embedded in the OM. However, in the microcosm experiment using intact cells, Omp52Sy and Omp48Sy were detected in the particulate fraction only during the first 4 days, after which they could not longer be detected. Omp52Sy and Omp48Sy were the most stable proteins among the Synechococcus OMPs in vitro, but they might be degraded in situ. This indicates that stability of Synechococcus porin differs depending on complex formation with other membrane molecules, which might cause different preservation of microbial membrane proteins in the dissolved protein pool in the ocean. This study suggests that Gram negative bacterial OM with thin peptidoglycan forms a lipid bilayer that proptects OMP, but Synechococcus OM with thick peptidoglycan cannot form a lipid bilayer. The incomplete bilayer might not be able to protect from protease attack in the natural environment.  相似文献   

Estimation of underwater scattering radiances up to the third order     

Yasuhiro Sugimori  Tatsuo Hasemi 《Journal of Oceanography》1971,27(2):73-80

Vertical distribution of underwater scattering radiances of the first, the second and the third order is estimated by the Jerlov's method. In the estimation the volume attenuation coefficient and the volume scattering function are assumed to be constant in near surface layer, and the sky radiation separated from solar radiation to be a parallel beam and to fall into the sea in the vertical direction only.In the zenith direction the second scattering radiance is more intense than the first scattering radiance in near surface layer. As for the total radiance which is a sum of radiances up to the third order, the zenith radiation is largest, the nadir radiation is moderate and the horizontal radiation is least.  相似文献   

The study of lead-210 in the marine environment     

Yoshiyuki Nozaki 《Journal of Oceanography》1977,33(6):342-349

This article summarizes the author's work on²¹⁰Pb and²¹⁰Po distributions in the marine environment for which the Okada Prize of the Oceanographical Society of Japan was awarded. In this review, the work of other investigators and the studies now going on are also included. The²¹⁰Pb concentration in the surface water of the ocean is controlled by the atmospheric flux of²¹⁰Pb and productivity. The disequilibrium between²²⁶Ra and²¹⁰Pb in the deep sea reveals that the oceanic residence time of lead is less than a hundred years rather than of the order of thousands of years as thought before based on stable lead measurement in ocean water. Particulate removal of²¹⁰Pb from the water column is likely to be the major cause of the deficiency of²¹⁰Pb in the water, however more investigations would be needed to clarify the detailed removal mechanism of²¹⁰Pb. The experiments on particulate flux by using sediment traps will provide an unique opportunity to examine this. ²¹⁰Pb in excess of²²⁶Ra in sediment is useful for geochronology of shallow water sediments and the study on bioturbation rates on the deep sea sediments.  相似文献   

Spirits of Yokokurayama: shrine of the Japanese trilobites     

Christopher Stocker  Mark Williams  Tatsuo Oji  Gengo Tanaka  Toshifumi Komatsu  Simon Wallis 《Geology Today》2019,35(1):15-19

‘We are such stuff as dreams are made on, and our little life is rounded with a sleep’. So sleep the trilobites of Yokokurayama, a sacred mountain hidden within the beautiful landscape of Japan’s Shikoku’s island. And though Prospero may have been speaking to his daughter and her fiancé (in William Shakespeare’s The Tempest), he might well have been contemplating the magnificent trilobite fossils of Yokokurayama. Japan may be better known for its sweeping volcanic landscapes, majestic castles, Shinto shrines and bullet trains, but it is also home to important collections of Silurian and Devonian trilobites.  相似文献   

Dragons,brimstone and the geology of a volcanic arc on the island of the last Samurai,Kyushu, Japan     

Mark Williams  Simon Wallis  Toshifumi Komatsu  Gengo Tanaka  Tatsuo Oji  Nicola Clark 《Geology Today》2016,32(1):21-26

Not even Hollywood could dream of a place so magical as Kyushu. The southern‐most of the four major islands of the Japanese archipelago, this is a land of volcanoes, dinosaurs, and the last stand of the Samurai. And for good measure, James Bond visited here too, in the 1967 film You Only Live Twice. The final explosive scenes of that film featured the destruction of megalomaniac Ernst Stavro Blofeld's headquarters hidden inside the crater of one of Kyushu's most emblematic volcanoes, Shinmoedake. Kyushu also straddles the largest geological structure in Japan, the Median Tectonic Line (MTL) that runs from the western approaches of the island to the central part of Honshu. The MTL has been active since the Cretaceous, and the sedimentary basins formed along its line in Kyushu contain some of Japan's most famous dinosaur finds. The MTL also defines a fundamental divide between the geological histories of the terranes north and south of its line, a history that takes us back to the origins of the Japanese archipelago half a billion years ago.  相似文献   

Size distribution of condensed aromatic rings in various soil humic acids     

Kosuke Ikeya  Tatsuo HikageShigeo Arai  Akira Watanabe 《Organic Geochemistry》2011,42(1):55-61

Condensed aromatic rings are important skeletal components with regard to the recalcitrant nature of humic acids (HAs) in the environment. However, they have not been extensively studied. The relative content and composition (size distribution) of condensed aromatic rings in HAs were obtained from various soils subjected to transmission electron microscopy (TEM) and X-ray diffraction (XRD) profile analysis. In the XRD profiles of all the HAs, the 11 band that was derived from the carbon layer planes was clearly observed. Analysis of the 11 band indicated that the size of the carbon layer planes in HAs ranged from 0.48-1.68 nm, corresponding to 4- to 37-ring condensed aromatic structures. The contents of the total and larger carbon layer planes were larger in HAs with darker color and larger aromatic carbon content. At the same time, the carbon layer planes in HAs were smaller than those in a carbon black reference (from 0.24 to >3.66 nm). In the TEM analysis, fringes observed in HAs were less distinct and less ordered than those in carbon black, which was in agreement with the XRD result.  相似文献   

Numerical investigation on the performance of Wells turbine with non-uniform tip clearance for wave energy conversion     

Zahari Taha  Sugiyono  T.M.Y.S. Tuan Ya  Tatsuo Sawada 《Applied Ocean Research》2011,33(4):321-331

The performance of a Wells turbine with various non-uniform tip clearances was investigated using computational fluid dynamics (CFD). The investigation was performed on numerical models of a NACA0020 blade profile under steady flow conditions. The performance of turbines with uniform and non-uniform tip clearances was compared. The results were also compared with experimental results in literature. It was shown that the performance of turbine with non-uniform tip clearance is similar with that of turbine with uniform one in terms of torque coefficient, input power coefficient, and efficiency. However, the turbine with non-uniform tip clearance seems to have a preferable overall performance. An investigation on the flow-field around the turbine blade was performed in order to explain the phenomena.  相似文献   

Simulating present climate of the global ocean–ice system using the Meteorological Research Institute Community Ocean Model (MRI.COM): simulation characteristics and variability in the Pacific sector     

Hiroyuki Tsujino  Mikitoshi Hirabara  Hideyuki Nakano  Tamaki Yasuda  Tatsuo Motoi  Goro Yamanaka 《Journal of Oceanography》2011,67(4):449-479

A long-term spin-up and a subsequent interannual simulation are conducted for the ocean–ice component of the climate model intercomparison project (CMIP)-class earth system model of the Japan Meteorological Agency/Meteorological Research Institute. This experiment has three purposes: first is to assess the ability of our model with the Coordinated Ocean–ice Reference Experiments (COREs) forcing in reproducing the present ocean-climate; second is to understand the ocean-climate variability for the past 60 years; third is to present an example of evaluating an ocean–ice interannual variability simulation. The Pacific Ocean is focused on for the last two purposes. After integrating for about 1500 years with repeated use of a detrended CORE interannual forcing, the model reaches a quasi-steady state where the present climate is reproduced satisfactorily. Then, the interannual variability simulation is conducted with the retrieved forcing trend and the result is analyzed. The simulation is successful at reproducing the long-term variability in the Pacific and surrounding oceans. Brief analyses of the tropical and mid-latitude upper layer, deep circulation, and the Arctic sea ice are presented. A caveat in treating other parts of the globe is due to the recent intense convection in the Southern Ocean caused by a remarkably increasing trend of the Southern Hemisphere westerly. Overall, the current simulation with our CMIP-class ocean–ice model is shown to be useful for studying the present ocean-climate variability, specifically in the Pacific sector. It could also be used as a benchmark control experiment that facilitates further research, model development, and intercomparison.  相似文献   

A GC×GC-ToFMS Investigation of the Unresolved Complex Mixture and Associated Biomarkers in Biodegraded Petroleum     

WANG Guangli  Bernd Rolf Tatsuo SIMONEIT  SHI Shengbao  WANG Tieguan  ZHONG Ningning  WANG Peirong 《《地质学报》英文版》2018,92(5):1959-1972

Heavy biodegraded crude oils have larger numbers of coeluting compounds than non-biodegraded oils, and they are typically not resolved with conventional gas chromatography (GC). This unresolved complex mixture (UCM) has been investigated using comprehensive two- dimensional gas chromatography–time-of-flight mass spectrometry (GC×GC-ToFMS) within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan (Neoproterozoic, marine), Tarim (Early Paleozoic, marine), Bohai Bay (Eocene, saline/brackish) and Pearl River Mouth (Eocene, freshwater). In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A-norsteranes, series of 1,1,3-trimethyl-2-alkylcyclohexanes (carotenoid-derived alkanes), and tetralin and indane compounds, respectively.  相似文献   

Bulk mineralogical changes of hydrous micrometeorites during heating in the upper atmosphere at temperatures below 1000 °C     

Wataru Nozaki  Tomoki Nakamura  Takaaki Noguchi 《Meteoritics & planetary science》2006,41(7):1095-1114

Abstract— Small particles 200 μm in diameter from the hydrous carbonaceous chondrites Orgueil CI, Murchison CM2, and Tagish Lake were experimentally heated for short durations at subsolidus temperatures under controlled ambient pressures in order to examine the bulk mineralogical changes of hydrous micrometeorites during atmospheric entry. The three primitive meteorites consist mainly of various phyllosilicates and carbonates that are subject to decomposition at low temperatures, and thus the brief heating up to 1000 °C drastically changed the mineralogy. Changes included shrinkage of interlayer spacing of saponite due to loss of molecular water at 400–600 °C, serpentine and saponite decomposition to amorphous phases at 600 and 700 °C, respectively, decomposition of Mg‐Fe carbonate at 600 °C, recrystallization of secondary olivine and Fe oxide or metal at 700–800 °C, and recrystallization of secondary low‐Ca pyroxene at 800 °C. The ambient atmospheric pressures controlled species of secondary Fe phase: taenite at pressures lower than 10^?2 torr, magnesiowüstite from 10^?3 to 10^?1 torr, and magnetite from 10^?2 to 1 torr. The abundance of secondary low‐Ca pyroxene increases in the order of Murchison, Orgueil, and Tagish Lake, and the order corresponds to saponite abundance in samples prior to heating. Mineralogy of the three unmelted micrometeorites F96CI024, kw740052, and kw740054 were investigated in detail in order to estimate heating conditions. The results showed that they might have come from different parental objects, carbonaterich Tagish Lake type, carbonate‐poor Tagish Lake or CI type, and CM type, respectively, and experienced different peak temperatures, 600, 700, and 800?900 °C, respectively, at 60–80 km altitude upon atmospheric entry.  相似文献