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  • Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP  (5)
  • Biochemistry and Biotechnology
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Cell Biochemistry and Function 11 (1993), S. 225-230 
    ISSN: 0263-6484
    Keywords: Electrophoresis ; endothelia ; glycoproteins ; lectins ; smooth muscle cells ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Endothelial and smooth muscle cells were isolated from porcine aorta and kept in short-term culture. To determine the terminal carbohydate composition of the plasma membranes from both cell populations, the cells were incubated with a panel of fluorescein-labelled lectins. Both cell populations shared a number of terminal carbohydrates, but the N-galactosamine specific lectin Wistaria floribunda agglutinin labelled only the endothelial cells. A lectin which selectively labelled smooth muscle cells was not found. Western blot analysis of isolated endothelial cell membrane glycoproteins indicated that most membrane glycoproteins are labelled by Wistaria floribunda agglutinin.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0173-0835
    Keywords: Bacillus subtilis ; Two-dimensional polyacrylamide gel electrophoresis ; Protein index ; Stress proteins ; SigmaB ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Data on the identification of proteins of Bacillus subtilis on two-dimensional (2-D) gels as well as their regulation are summarized and the identification of 56 protein spots is included. The pattern of proteins synthesized in Bacillus subtilis during exponential growth, during starvation for glucose or phosphate, or after the imposition of stresses like heat shock, salt- and ethanol stress as well as oxidative stress was analyzed. N-terminal sequencing of protein spots allowed the identification of 93 proteins on 2-D gels, which are required for the synthesis of amino acids and nucleotides, the generation of ATP, for glycolyses, the pentose phosphate cycle, the citric acid cycle as well as for adaptation to a variety of stress conditions. A computer-aided analysis of the 2-D gels was used to monitor the synthesis profile of more than 130 protein spots. Proteins performing housekeeping functions during exponential growth displayed a reduced synthesis rate during stress and starvation, whereas spots induced during stress and starvation were classified as specific stress proteins induced by a single stimulus or a group of related stimuli, or as general stress proteins induced by a variety of entrely different stimuli. The analysis of mutants in global regulators was initiated in order to establish a response regulation map for B. subtilis. These investigations demonstrated that the alternative sigma factor σB is involved in the regulation of almost all of the general stress proteins and that the phoPR two-component system is required for the induction of a large part but not all of the proteins induced by phosphate starvation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
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    PANGAEA
    In:  Supplement to: Cavaleiro, Catarina; Voelker, Antje H L; Stoll, Heather M; Baumann, Karl-Heinz; Kulhanek, Denise K; Naafs, Bernhard David A; Stein, Ruediger; Gruetzner, Jens; Ventura, C; Kucera, Michal (2018): Insolation forcing of coccolithophore productivity in the North Atlantic during the Middle Pleistocene. Quaternary Science Reviews, 191, 318-336, https://doi.org/10.1016/j.quascirev.2018.05.027
    Publication Date: 2023-02-24
    Description: Coccolithophores play a key role in the oceanic carbon cycle through the biological and carbonate pumps. Understanding controls on coccolithophore productivity is thus fundamental to quantify oceanic carbon cycling. We investigate changes in coccolithophore productivity over several Pleistocene glacial-interglacial cycles using a high-resolution coccolith Sr/Ca ratio record, which is an indicator of growth rate and thus a proxy for coccolithophore productivity. We use Middle Pleistocene sediments from the North Atlantic Integrated Ocean Drilling Program (IODP) Site U1313 (41.00' N, 32.58' W) spanning Marine Isotopic Stages 16 to 10 (638 to 356 kyr). The location of the record allows us to investigate processes affecting productivity in a mid-latitude setting and to unravel the effects of temperature and regional ocean circulation. Coccolithophore productivity shows a dominant glacial-interglacial cyclicity with higher productivity during glacials, which appears to reflect the southward migration of the North Atlantic high productivity zone currently located between 45º and 55º N. Spectral analysis of the productivity record reveals a suborbital variability consistent with forcing by insolation maxima superimposed on the front migration pattern. Similar to today, coccolithophore productivity during interglacials was enhanced when insolation was at its maximum in spring or in autumn, whereas during glacials, productivity was enhanced when summer/autumn insolation was at its maximum. We show that in the studied region, coccolithophore productivity was driven by processes reflecting regional insolation. Applying this information to model experiments is required to assess if coccolithophore productivity played a significant role in past changes of atmospheric CO2.
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 6 datasets
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  • 4
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    PANGAEA
    In:  Supplement to: Bahr, André; Jiménez-Espejo, Francisco Jose; Kolasinac, Nada; Grunert, Patrick; Hernandéz-Molina, Francisco Javier; Röhl, Ursula; Voelker, Antje H L; Escutia, Carlota; Stow, Dorrik A V; Alvarez Zarikian, Carlos A; Hodell, David A (2014): Deciphering bottom current strength and paleoclimate signals from contourite deposits in the Gulf of Cádiz during the last 140 kyr: an inorganic geochemical approach. Geochemistry, Geophysics, Geosystems, 15(8), 3145-3160, https://doi.org/10.1002/2014GC005356
    Publication Date: 2023-12-20
    Description: Contourites in the Gulf of Cádiz preserve a unique archive of Mediterranean Outflow Water (MOW) variability over the past 5.3 Ma. In our study we investigate the potential of geochemical data obtained by XRF scanning to decipher bottom current processes and paleoclimatic evolution at two different sites drilled through contourite deposits in the northern Gulf of Cadiz: Site U1387, which is bathed by the upper MOW core, and Site U1389, located more proximal to the Straits of Gibraltar. The lack of major downslope transport at both locations during the Pleistocene makes them ideal locations for the purpose of our study. The results indicate that the Zr/Al ratio, representing the relative enrichment of heavy minerals (zircon) over less dense alumosilicates under strong bottom current flow, is the most useful indicator for a semi-quantitative assessment of current strength. While most elements are biased by current-related processes, the bromine record, representing organic content, preserves the most pristine climate signal rather independent of grain size changes. Hence, Br can be used for chronostratigraphy and site-to-site correlation in addition to stable isotope stratigraphy. Based on these findings we reconstructed MOW variability for Marine Isotope Stages 1-5 using the Zr/Al ratio from Site U1387. The results reveal abrupt, millennial-scale variations of MOW strength during Greenland Stadials (GS) and Interstadials (GI) with strong MOW during GS and glacial Terminations and a complex behavior during Heinrich Stadials. Millennial-scale variability persisting during periods of poorly expressed GS/GI cyclicities implies a strong internal oscillation of the Mediterranean/North Atlantic climate system.
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 8 datasets
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  • 5
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    PANGAEA
    In:  Supplement to: García-Gallardo, Ángela; Grunert, Patrick; Voelker, Antje H L; Mendes, Isabel Maria de Paiva Pinto; Piller, Werner E (2017): Re-evaluation of the "elevated epifauna" as indicator of Mediterranean Outflow Water in the Gulf of Cadiz using stable isotopes (d13C, d18O). Global and Planetary Change, 155, 78-97, https://doi.org/10.1016/j.gloplacha.2017.06.005
    Publication Date: 2024-02-19
    Description: The presence and high abundances of the benthic foraminiferal group "elevated epifauna" has been proposed as indicator of the existence of Mediterranean Outflow Water (MOW) in the Gulf of Cadiz. Here we intend to use this potential proxy to reconstruct MOW in the early Pliocene at the Integrated Ocean Drilling Program (IODP) Hole U1387C. Cibicides lobatulus, Planulina ariminensis and Cibicides refulgens were found at this site, but high abundances of C. lobatulus and C. refulgens coincide with increases of shelf taxa and grain size, related to episodes of downslope transport. This issue calls into question the applicability of these species as MOW proxies. The present study therefore reassesses the role of these three elevated epifaunal species by means of stable isotope analyses (d18O, d13C) by contrasting their isotopic signature with that of shelf dwellers and deep-water taxa from Pliocene and Recent sediments from the Gulf of Cadiz and the western Iberian margin. Since foraminiferal calcite does not always precipitate in equilibrium with seawater, substantial efforts have been taken in order to determine species-specific offset values and to correct the isotopic signature for vital effects. Our corrected results demonstrate that C. lobatulus and C. refulgens are isotopically similar to the shelf dwellers in the Pliocene data-set, eliminating them as MOW indicators. Recent samples from the Gulf of Cadiz and the western Portugal shelf corroborate the wide bathymetric range of C. lobatulus from the shelf to the slope. Our results thus warrant for caution when considering C. lobatulus and C. refulgens as indicators of bottom current strength in unstable slope settings, particularly when co-occurring with allochthonous shelf dwellers. In contrast, P. ariminensis shows a signature close to deep-water taxa, corroborating its reliability as indicator of MOW.
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 6
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    PANGAEA
    In:  Supplement to: Lofi, Johanna; Voelker, Antje H L; Ducassou, Emmanuelle; Hernandéz-Molina, Francisco Javier; Sierro, Francisco Javier; Bahr, André; Galvani, Aurélie; Lourens, Lucas Joost; Pardo-Igúzquiza, Eulogio; Pezard, Philippe A; Rodríguez-Tovar, Francisco Javier; Williams, Trevor (2016): Quaternary chronostratigraphic framework and sedimentary processes for the Gulf of Cadiz and Portuguese Contourite Depositional Systems derived from Natural Gamma Ray records. Marine Geology, 377, 40-57, https://doi.org/10.1016/j.margeo.2015.12.005
    Publication Date: 2024-01-22
    Description: The Contourite Depositional Systems (CDS) in the Gulf of Cádiz and on the West Iberian margin preserve a unique archive of Mediterranean Outflow Water (MOW) variability over the past 5.3 Ma. These CDS have been recently drilled in several places during the IODP Expedition 339. These drill sites now offer a new window to the internal Pliocene and Quaternary architecture of the CDS. In this study, we use downhole and core Gamma Ray (GR) data acquired from 5 sites drilled in the CDS along the middle slope and 1 site drilled in the deeper setting of the lower slope, out of the MOW path. The GR data primarily tracks the clay content in the sediment and is the expression of sediment supply and, for sites drilled in the CDS, of the bottom current processes. Both appear astronomically controlled as shown by spectral analysis performed on the GR data. Results also reveal that the GR log patterns correlate well across the sites over the last 1.4 My. Several GR horizons corresponding to drops in GR values were identified, most of which fit with coarse-grained deposits observed in cores and interpreted as contourite beds. The GR horizons are interpreted as isochronous horizons, providing a regional scale chronostratigraphic framework for the CDS depositional records with an accuracy of ~ 20 ky. We further assess the spatial and temporal variability of the CDS hiatuses at the regional scale.
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 7
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    PANGAEA
    In:  Supplement to: Voelker, Antje H L; Salgueiro, Emilia; Rodrigues, Teresa; Jiménez-Espejo, Francisco Jose; Bahr, André; Alberto, Ana; Loureiro, Isabel; Padilha, Mária; Rebotim, Andreia; Röhl, Ursula (2015): Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020–1135ka). Global and Planetary Change, 133, 223-237, https://doi.org/10.1016/j.gloplacha.2015.08.015
    Publication Date: 2024-02-24
    Description: Centennial-to-millennial scale records from IODP Site U1387, drilled during IODP Expedition 339 into the Faro Drift at 558 m water depth, now allow evaluating the climatic history of the upper core of the Mediterranean Outflow (MOW) and of the surface waters in the northern Gulf of Cadiz during the early Pleistocene. This study focuses on the period from Marine Isotope Stage (MIS) 29 to 34, i.e. the interval surrounding extreme interglacial MIS 31. Conditions in the upper MOW reflect obliquity, precession and millennial-scale variations. The benthic d18O signal follows obliquity with the exception of an additional, smaller d18O peak that marks the MIS 32/31 transition. Insolation maxima (precession minima) led to poor ventilation and a sluggish upper MOW core, whereas insolation minima were associated with enhanced ventilation and often also increased bottom current velocity. Millennial-scale periods of colder sea-surface temperatures (SST) were associated with short-term maxima in flow velocity and better ventilation, reminiscent of conditions known from MIS 3. A prominent contourite layer, coinciding with insolation cycle 100, was formed during MIS 31 and represents one of the few contourites developing within an interglacial period. MIS 31 surface water conditions were characterized by an extended period (1065-1091 ka) of warm SST, but SST were not much warmer than during MIS 33. Interglacial to glacial transitions experienced 2 to 3 stadial/interstadial cycles, just like their mid-to-late Pleistocene counterparts. Glacial MIS 30 and 32 recorded periods of extremely cold (〈 12°C) SST that in their climatic impact were comparable to the Heinrich events of the mid and late Pleistocene. Glacial MIS 34, on the other hand, was a relative warm glacial period off southern Portugal. Overall, surface water and MOW conditions at Site U1387 show strong congruence with Mediterranean climate, whereas millennial-scale variations are closely linked to North Atlantic circulation changes.
    Keywords: Integrated Ocean Drilling Program / International Ocean Discovery Program; IODP
    Type: Dataset
    Format: application/zip, 5 datasets
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