191 research outputs found

    Diazotrophy drives primary production in the organic-rich shales deposited under a stratified environment during the messinian salinity crisis (Vena Del Gesso, Italy)

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    Density stratification between freshwater and brine is periodically formed during massive evaporation events, which often associates deposition of organic-rich sediments. Here, we investigated phototrophic communities and nitrogen cycle during the deposition of two organic-rich shale beds of gypsum\u2013shale alternation, representing the initial stage of the Messinian salinity crisis (Vena del Gesso, Northern Apennines, Italy). The structural distributions and the carbon and nitrogen isotopic compositions of geoporphyrins show a common pattern in the two shales, indicating the predominance of a particular phototrophic community under freshwater\u2013brine stratified conditions. The 3c6\u2030 difference in \u3b413C of total organic carbon between PLG 4 and 5 shales was associated with similar shift in \u3b413C of the porphyrins derived from chlorophyll c, suggesting that the eukaryotic algae producing chlorophyll c were the major constituent of the phototrophic community. Importantly, these porphyrins show \u3b415N values (-7.6\u2013-4.7\u2030) indicative of N2-fixation. We suggest that nitrate-depletion in the photic zone induced the predominance of diazotrophic cyanobacteria, which supplied new nitrogen for the chlorophyll c-producing eukaryotic algae. The large difference in the \u3b413C values of porphyrins and total organic carbon between PLG 4 and 5 shales are interpreted to reflect the depth of the chemocline, which fluctuates in response to changes in the regional evaporation\u2013precipitation balance. Such variation in the chemocline depth may have dynamically changed the mode of the nitrogen cycle (i.e., nitrification\u2013denitrification\u2013N2-fixation coupling vs. phototrophic assimilation of ammonium) in the density-stratified marginal basins during the Messinian salinity crisis

    Biomarker records and mineral compositions of the Messinian halite and K–Mg salts from Sicily

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    The evaporites of the Realmonte salt mine (Sicily, Italy) are important archives recording the most extreme conditions of the Messinian Salinity Crisis (MSC). However, geochemical approach on these evaporitic sequences is scarce and little is known on the response of the biological community to drastically elevating salinity. In the present work, we investigated the depositional environments and the biological community of the shale–anhydrite–halite triplets and the K–Mg salt layer deposited during the peak of the MSC. Both hopanes and steranes are detected in the shale–anhydrite–halite triplets, suggesting the presence of eukaryotes and bacteria throughout their deposition. The K–Mg salt layer is composed of primary halites, diagenetic leonite, and primary and/or secondary kainite, which are interpreted to have precipitated from density-stratified water column with the halite-precipitating brine at the surface and the brineprecipitating K–Mg salts at the bottom. The presence of hopanes and a trace amount of steranes implicates that eukaryotes and bacteria were able to survive in the surface halite-precipitating brine even during the most extreme condition of the MSC.This work was performed with the support of Japan Society for the Promotion of Science (JSPS) Research Fellowship (16 J07844) to YI and JAMSTEC President Fund to NO

    Management strategy for acute pancreatitis in the JPN Guidelines

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    The diagnosis of acute pancreatitis is based on the following findings: (1) acute attacks of abdominal pain and tenderness in the epigastric region, (2) elevated blood levels of pancreatic enzymes, and (3) abnormal diagnostic imaging findings in the pancreas associated with acute pancreatitis. In Japan, in accordance with criteria established by the Japanese Ministry of Health, Labour, and Welfare, the severity of acute pancreatitis is assessed based on the clinical signs, hematological findings, and imaging findings, including abdominal contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI). Severity must be re-evaluated, especially in the period 24 to 48 h after the onset of acute pancreatitis, because even cases diagnosed as mild or moderate in the early stage may rapidly progress to severe. Management is selected according to the severity of acute pancreatitis, but it is imperative that an adequate infusion volume, vital-sign monitoring, and pain relief be instituted immediately after diagnosis in every patient. Patients with severe cases are treated with broad-spectrum antimicrobial agents, a continuous high-dose protease inhibitor, and continuous intraarterial infusion of protease inhibitors and antimicrobial agents; continuous hemodiafiltration may also be used to manage patients with severe cases. Whenever possible, transjejunal enteral nutrition should be administered, even in patients with severe cases, because it seems to decrease morbidity. Necrosectomy is performed when necrotizing pancreatitis is complicated by infection. In this case, continuous closed lavage or open drainage (planned necrosectomy) should be the selected procedure. Pancreatic abscesses are treated by surgical or percutaneous drainage. Emergency endoscopic procedures are given priority over other methods of management in patients with acute gallstone-associated pancreatitis, patients suspected of having bile duct obstruction, and patients with acute gallstone pancreatitis complicated by cholangitis. These strategies for the management of acute pancreatitis are shown in the algorithm in this article

    Efficient recycling of nutrients in modern and past hypersaline environments

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    The biogeochemistry of hypersaline environments is strongly influenced by changes in biological processes and physicochemical parameters. Although massive evaporation events have occurred repeatedly throughout Earth history, their biogeochemical cycles and global impact remain poorly understood. Here, we provide the first nitrogen isotopic data for nutrients and chloropigments from modern shallow hypersaline environments (solar salterns, Trapani, Italy) and apply the obtained insights to δ15N signatures of the Messinian salinity crisis (MSC) in the late Miocene. Concentrations and δ15N of chlorophyll a, bacteriochlorophyll a, nitrate, and ammonium in benthic microbial mats indicate that inhibition of nitrification suppresses denitrification and anammox, resulting in efficient ammonium recycling within the mats and high primary productivity. We also suggest that the release of 15N-depleted NH3(gas) with increasing salinity enriches ammonium 15N in surface brine (≈34.0‰). Such elevated δ15N is also recorded in geoporphyrins isolated from sediments of the MSC peak (≈20‰), reflecting ammonium supply sufficient for sustaining phototrophic primary production. We propose that efficient nutrient supply combined with frequent bottom-water anoxia and capping of organic-rich sediments by evaporites of the Mediterranean MSC could have contributed to atmospheric CO2 reduction during the late Miocene.This study was partly supported by a Japan Society for the Promotion of Science (JSPS) Research Fellowship (16J07844) to YI, Grants-in-Aid (16H02236) and the JAMSTEC President Fund to NO

    Ecological Effects of Major Storms on Coastal Watersheds and Coastal Waters: Hurricane Bob on Cape Cod

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    Hurricane Bob, a category 3 storm, made landfall on Cape Cod in August 1991, and its effects on watersheds and adjoining estuaries were detected in the ongoing studies being caried out as part of the Waquoit Bay Land Margin Ecosystems Research project. On land, Bob had only minor overall effects on forests; localized wind bursts did snap and break trees in small and widely scattered forest parcels. Wind stripped up to half the leaves of deciduous trees and many herbaceous plants on the watershed, and most remaining leaves were damaged by salt, so that by the end of Aug, Cape Cod forests were defoliated. Damaged growing tips of exposed trees were evident for several growing seasons. The salt exposure was followed by a burst of growth and bloom in some plants during Sep-Oct. Forest invertebrates were disturbed by the storm. Nests of hornets and wasps, for example, were apparently destroyed and the survivors became a serious pest problem: hospital records show a ten-fold increase in cases of wasp stings just after Bob. Populations of these insects did not return to earlier abundance for several years. Birds and mammals did not appear to have suffered much damage. Leaching of salt to soils released previously-adsorbed soil ammonium. Such loss of critical nitrogen may be in part responsible for the characteristically dwarfed near-shore coastal forests, as well as adds nitrogen to groundwater that in turn transports the nitrogen to receiving waters. On the Bay, Bob thoroughly mixed the water column, but the stratification was restored within 1-2 days after passage of the storm. Short recovery times might be characteristic of shallow bays with short (2-3 d) water residence times. Bob opened a new inlet to Waquoit Bay, which remains open. The new inlet exerts only minor effects on circulation within the Bay, but did create localized damage to dune and eelgrass habitats near the new inlet. The mixing of the water column released major amounts of nutrients that were held within the macroalgal canopy and upper sediments, into the upper layers, and prompted a short-lived (2-3 d) phytoplankton bloom. Biomass of unattached macroalgae was not affected by Bob. Respiration and nitrogen content of the dominant macroalgal species were elevated after passage of the storm, but returned to normal rates after several days. Nearly all above-sediment eelgrass biomass was removed, but returned to previous biomass during the next growing season. There was no visible damage to fringing salt marsh habitats. Damage to aquatic animals appears to have been minimal. A small decrease in water temperature and increased respiration by macroalgae led to decreased total net ecosystem production and increased net ecosystem respiration, but the decreases disappeared after 2 d. The effects of Hurricane Bob seemed more intense and protracted on land than on aquatic ecosystems. Recovery from the various disturbances took hours to days in the aquatic system, but months to decades in terrestrial components. Rigid, larger organisms attached or rooted to substrates seem most subject to storm-related disturbances

    N-Glycosylation of ß4 Integrin Controls the Adhesion and Motility of Keratinocytes

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    α6ß4 integrin is an essential component of hemidesmosomes and modulates cell migration in wound healing and cancer invasion. To elucidate the role of N-glycosylation on ß4 integrin, we investigated keratinocyte adhesion and migration through the re-expression of wild-type or N-glycosylation-defective ß4 integrin (ΔNß4) in ß4 integrin null keratinocytes. N-glycosylation of ß4 integrin was not essential for the heterodimer formation of ß4 integrin with α6 integrin and its expression on a cell surface, but N-glycosylation was required for integrin-mediated cell adhesion and migration. Concomitantly with the reduction of ß4 integrin in the membrane microdomain, the intracellular signals of Akt and ERK activation were decreased in cells expressing ΔNß4 integrin. Forced cross-linking of ß4 integrin rescued the decreased ERK activation in ΔNß4 integrin-expressing cells to a similar extent in wild-type ß4 integrin-expressing cells. Surprisingly, compared with cells expressing wild-type ß4 integrin, an alternation in N-glycan structures expressed on epidermal growth factor receptor (EGFR), and the induction of a stronger association between EGFR and ß4 integrin were observed in ΔNß4 integrin-expressing cells. These results clearly demonstrated that N-glycosylation on ß4 integrin plays an essential role in keratinocyte cellular function by allowing the appropriate complex formation on cell surfaces

    Health insurance system and payments provided to patients for the management of severe acute pancreatitis in Japan

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    The health insurance system in Japan is based upon the Universal Medical Care Insurance System, which gives all citizens the right to join an insurance scheme of their own choice, as guaranteed by the provisions of Article 25 of the Constitution of Japan, which states: “All people shall have the right to maintain the minimum standards of wholesome and cultured living.” The health care system in Japan includes national medical insurance, nursing care for the elderly, and government payments for the treatment of intractable diseases. Medical insurance provisions are handled by Employee’s Health Insurance (Social Insurance), which mainly covers employees of private companies and their families, and by National Health Insurance, which provides for the needs of self-employed people. Both schemes have their own medical care service programs for retired persons and their families. The health care system for the elderly covers people 75 years of age and over and bedridden people 65 years of age and over. There is also a system under which the government pays all or part of medical expenses, and/or pays medical expenses not covered by insurance. This is referred to collectively as the “medical expenses payment system” and includes the provision of medical assistance for specified intractable diseases. Because severe acute pancreatitis has a high mortality rate, it is specified as an intractable disease. In order to lower the mortality rate of various diseases, including severe acute pancreatitis, the specification system has been adopted by the government. The cost of treatment for severe acute pancreatitis is paid in full by the government from the date the application is made for a certificate verifying that the patient has an intractable disease

    Loss and Recovery of Mgat3 and GnT-III Mediated E-cadherin N-glycosylation Is a Mechanism Involved in Epithelial-Mesenchymal-Epithelial Transitions

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    BACKGROUND: N-acetylglucosaminyltransferase-III (GnT-III) is a glycosyltransferase encoded by Mgat3 that catalyzes the addition of β1,4-bisecting-N-acetylglucosamine on N-glycans. GnT-III has been pointed as a metastases suppressor having varying effects on cell adhesion and migration. We have previously described the existence of a functional feedback loop between E-cadherin expression and GnT-III-mediated glycosylation. The effects of GnT-III-mediated glycosylation on E-cadherin expression and cellular phenotype lead us to evaluate Mgat3 and GnT-III-glycosylation role during Epithelial-Mesenchymal-Transition (EMT) and the reverted process, Mesenchymal-Epithelial-Transition (MET). METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the expression profile and genetic mechanism controlling Mgat3 expression as well as GnT-III-mediated glycosylation, in general and specifically on E-cadherin, during EMT/MET. We found that during EMT, Mgat3 expression was dramatically decreased and later recovered when cells returned to an epithelial-like phenotype. We further identified that Mgat3 promoter methylation/demethylation is involved in this expression regulation. The impact of Mgat3 expression variation, along EMT/MET, leads to a variation in the expression levels of the enzymatic product of GnT-III (bisecting GlcNAc structures), and more importantly, to the specific modification of E-cadherin glycosylation with bisecting GlcNAc structures. CONCLUSIONS/SIGNIFICANCE: Altogether, this work identifies for the first time Mgat3 glycogene expression and GnT-III-mediated glycosylation, specifically on E-cadherin, as a novel and major component of the EMT/MET mechanism signature, supporting its role during EMT/MET
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