Molecular Characterization of an Arabidopsis Gene Encoding Hydroperoxide Lyase, a Cytochrome P-450 That Is Wound Inducible1

Hydroperoxide lyase (HPL) cleaves lipid hydroperoxides to produce volatile flavor molecules and also potential signal molecules. We have characterized a gene from Arabidopsis that is homologous to a recently cloned HPL from green pepper (Capsicum annuum). The deduced protein sequence indicates that this gene encodes a cytochrome P-450 with a structure similar to that of allene oxide synthase. The gene was cloned into an expression vector and expressed in Escherichia coli to demonstrate HPL activity. Significant HPL activity was evident when 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid was used as the substrate, whereas activity with 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid was approximately 10-fold lower. Analysis of headspace volatiles by gas chromatography-mass spectrometry, after addition of the substrate to E. coli extracts expressing the protein, confirmed enzyme-activity data, since cis-3-hexenal was produced by the enzymatic activity of the encoded protein, whereas hexanal production was limited. Molecular characterization of this gene indicates that it is expressed at high levels in floral tissue and is wound inducible but, unlike allene oxide synthase, it is not induced by treatment with methyl jasmonate.

Black Sea and Caucasus Regions, 1774 (Image 1 of 3) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Carte de la partie septentrionale de l'Empire Otoman : dédiée a Monseigneur le comte de Vergennes--, par ... Rizzi Zannoni, de l'Académie Royale des Sciences et Belles Lettres de Gottingue, Pr. Ingénieur, Géographe du Roy ; Perrier sculpsit ; Bourgoin scripsit. It was published in 1774. Scale [ca. 1:1,450,000]. Covers the Black Sea and Caucasus regions. This layer is image 1 of 3 total images of the three sheet source map, representing the western portion of the map. Map in French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Europe Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, roads, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Black Sea and Caucasus Regions, 1774 (Image 2 of 3) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Carte de la partie septentrionale de l'Empire Otoman : dédiée a Monseigneur le comte de Vergennes--, par ... Rizzi Zannoni, de l'Académie Royale des Sciences et Belles Lettres de Gottingue, Pr. Ingénieur, Géographe du Roy ; Perrier sculpsit ; Bourgoin scripsit. It was published in 1774. Scale [ca. 1:1,450,000]. Covers the Black Sea and Caucasus regions. This layer is image 2 of 3 total images of the three sheet source map, representing the central portion of the map. Map in French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Europe Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, roads, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Black Sea and Caucasus Regions, 1774 (Image 3 of 3) (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Carte de la partie septentrionale de l'Empire Otoman : dédiée a Monseigneur le comte de Vergennes--, par ... Rizzi Zannoni, de l'Académie Royale des Sciences et Belles Lettres de Gottingue, Pr. Ingénieur, Géographe du Roy ; Perrier sculpsit ; Bourgoin scripsit. It was published in 1774. Scale [ca. 1:1,450,000]. Covers the Black Sea and Caucasus regions. This layer is image 3 of 3 total images of the three sheet source map, representing the eastern portion of the map. Map in French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Europe Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, roads, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown by hachures.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Dissolved organic carbon in sediments of the central Arctic Ocean collected during POLARSTERN cruise ARK-XXVII/3 from August-September 2012

Marine organic matter (OM) sinks from surface waters to the seafloor via the biological pump. Benthic communities, which use this sedimented OM as energy and carbon source, produce dissolved organic matter (DOM) in the process of remineralization, enriching the sediment porewater with fresh DOM compounds. We hypothesized that in the oligotrophic deep Arctic basin the molecular signal of freshly deposited primary produced OM is restricted to the surface sediment pore waters which should differ from bottom water and deeper sediment pore water in DOM composition. This study focused on: 1) the molecular composition of the DOM in sediment pore waters of the deep Eurasian Arctic basins, 2) whether the signal of marine vs. terrigenous DOM is represented by different compounds preserved in the sediment pore waters and 3) whether there is any relation between Arctic Ocean ice cover and DOM composition. Molecular data, obtained via 15 Tesla Fourier transform ion cyclotron resonance mass spectrometer, were correlated with environmental parameters by partial least square analysis. The fresher marine detrital OM signal from surface waters was limited to pore waters from < 5 cm sediment depth. The productive ice margin stations showed higher abundances of peptides, unsaturated aliphatics and saturated fatty acids formulae, indicative of fresh OM/pigments deposition, compared to northernmost stations which had stronger aromatic signals. This study contributes to the understanding of the coupling between the Arctic Ocean productivity and its depositional regime, and how it will be altered in response to sea ice retreat and increasing river runoff.

Data compilation of ESOP

The work in this sub-project of ESOP focuses on the advective and convective transforma-tion of water masses in the Greenland Sea and its neighbouring areas. It includes observational work on the sub-mesoscale and analysis of hydrographic data up to the gyre-scale. Observations of active convective plumes were made with a towed chain equipped with up to 80 CTD sensors, giving a horizontal and vertical resolution of the hydrographic fields of a few metres. The observed scales of the penetrative convective plumes compare well with those given by theory. On the mesoscale the structure of homogeneous eddies formed as a result of deep convection was observed and the associated mixing and renewal of the intermediate layers quantified. The relative importance and efficiency of thermal and haline penetrative convection in relation to the surface boundary conditions (heat and salt fluxes and ice cover) and the ambient stratification are studied using the multi year time series of hydro-graphic data in the central Greenland Sea. The modification of the water column of the Greenland Sea gyre through advection from and mixing with water at its rim is assessed on longer time scales. The relative contributions are quantified using modern water mass analysis methods based on inverse techniques. Likewise the convective renewal and the spreading of the Arctic Intermediate Water from its formation area is quantified. The aim is to budget the heat and salt content of the water column, in particular of the low salinity surface layer, and to relate its seasonal and interannual variability to the lateral fluxes and the fluxes at the air-sea-ice interface. This will allow to estimate residence times for the different layers of the Greenland Sea gyre, a quantity important for the description of the Polar Ocean carbon cycle.