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| 2. |
- Bykova, Natalia V., et al.
(författare)
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Two separate transhydrogenase activities are present in plant mitochondria
- 1999
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 265:1, s. 106-111
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Tidskriftsartikel (refereegranskat)abstract
- Inside-out submitochondrial particles from both potato tubers and pea leaves catalyze the transfer of hydride equivalents from NADPH to NAD+ as monitored with a substrate-regenerating system. The NAD+ analogue acetylpyridine adenine dinucleotide is also reduced by NADPH and incomplete inhibition by the complex I inhibitor diphenyleneiodonium (DPI) indicates that two enzymes are involved in this reaction. Gel-filtration chromatography of solubilized mitochondrial membrane complexes confirms that the DPI-sensitive TH activity is due to NADH-ubiquinone oxidoreductase (EC 1.6.5.3, complex I), whereas the DPI-insensitive activity is due to a separate enzyme eluting around 220 kDa. The DPI-insensitive TH activity is specific for the 4B proton on NADH, whereas there is no indication of a 4A-specific activity characteristic of a mammalian-type energy-linked TH. The DPI-insensitive TH may be similar to the soluble type of transhydrogenase found in, e.g., Pseudomonas. The presence of non-energy-linked TH activities directly coupling the matrix NAD(H) and NADP(H) pools will have important consequences for the regulation of NADP-linked processes in plant mitochondria.
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| 3. |
- Fredlund, K.M, et al.
(författare)
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NADH-ferricyanide reductases in plant membranes
- 1996
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Ingår i: Plant Membrane Biology- Proceedings of the Phytochemical Society of Europe -38. ; , s. 143-151
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Hjort, Christian, et al.
(författare)
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Holocene deglaciation and climate history of the northern Antarctic Peninsula region : a discussion of correlations between the Southern and Northern Hemispheres
- 1998
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Ingår i: ; , s. 110-112
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Konferensbidrag (refereegranskat)abstract
- The chronology of post-last Glacial Maximum dceglaciation in the northern Antarctic Peninsula region is discussed. It is concluded that, contrary to what was earlier believed, the deglaciation process here was largely out-of-phase with that in the Northern Hemisphere. Although, for global eustatic reasons, the marine-based glaciers may have retreated simultaneously with ice-melting in the Northern Hemisphere, the land-based glaciers retreated only slowly during the first half of the Hulocene, about 9000-5000 BP. This may have been due either to increased precipitation counterweighing ablation or to delayed warming: A distinct but rather brief glacial readvance took place. around 5000 BP, probably caused by a period of renewed cooling It was followed by the Holocene climatic optimum, about 4000-3000 Be This warm "hypsithermal" period thus came much later than its equivalent in the Northern Hemisphere, but it roughly coincided with the Milankovitchean Holocene insolation maximum for these southern latitudes.
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| 5. |
- Hjort, Christian, et al.
(författare)
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Holocene glacial history and sea level changes on James Ross Island, Antarctic Peninsula
- 1997
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Ingår i: Journal of Quaternary Science. - 1099-1417. ; 12:4, s. 259-273
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Tidskriftsartikel (refereegranskat)abstract
- A reconstruction of deglaciation and associated sea-level changes on northern James Ross Island, Antarctic Peninsula, based on lithostratigraphical and geomorphological studies, shows that the initial deglaciation of presently ice-free areas occurred slightly before 7400 14C yr BP. Sea-level in connection with the deglaciation was around 30 m a.s.l. A glacier readvance in Brandy Bay, of at least 7 km, with the initial 3 km over land, reached a position off the present coast at ca. 4600 yr BP. The culmination of the advance was of short duration, and by 4300 yr BP the coastal lowlands again were ice-free. A distinct marine level at 16–18 m a.s.l. was contemporaneous with or slightly post-dates the Brandy Bay advance, thus indicating the relative sea-level around 4600–4500 yr BP. Our results from James Ross Island confirm that over large areas in this part of Antarctica the last deglaciation occurred late.
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| 6. |
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| 7. |
- Ingolfsson, O., et al.
(författare)
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Antarctic glacial history since the Last Glacial Maximum: an overview of the record on land
- 1998
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Ingår i: Antarctic Science. - 1365-2079. ; 10:3, s. 326-344
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Tidskriftsartikel (refereegranskat)abstract
- This overview examines available circum-Antarctic glacial history archives on land, related to developments after the Last Glacial Maximum (LGM). It considers the glacial-stratigraphic and morphologic records and also biostratigraphical information from moss banks, lake sediments and penguin rookeries, with some reference to relevant glacial marine records. It is concluded that Holocene environmental development in Antarctica differed from that in the Northern Hemisphere. The initial deglaciation of the shelf areas surrounding Antarctica took place before 10 000 14C yrs before present (BP), and was controlled by rising global sea level. This was followed by the deglaciation of some presently ice-free inner shelf and land areas between 10 000 and 8000 yr BP. Continued deglaciation occurred gradually between 8000 yr BP and 5000 yr BP. Mid-Holocene glacial readvances are recorded from various sites around Antarctica. There are strong indications of a circum-Antarctic climate warmer than today 4700-2000 yr BP. The best dated records from the Antarctic Peninsula and coastal Victoria Land suggest climatic optimums there from 4000-3000 yr BP and 3600-2600 yr BP, respectively. Thereafter Neoglacial readvances are recorded. Relatively limited glacial expansions in Antarctica during the past few hundred years correlate with the Little Ice Age in the Northern Hemisphere.
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| 8. |
- Landvik, Jon Y., et al.
(författare)
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The Quaternary record of eastern Svalbard - an overview
- 1995
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Ingår i: Polar Research. - 0800-0395. ; 14:2, s. 95-103
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Tidskriftsartikel (refereegranskat)abstract
- The eastern part of the Svalbard archipelago and the adjacent areas of the Barents Sea were subject to extensive erosion during the Late Weichselian glaciation. Small remnants of older sediment successions have been preserved on Edgeoya, whereas a more complete succession on Kongsoya contains sediments from two different ice-free periods, both probably older than the Early Weichselian. Ice movemeht indicators in th eregion suggest that the Late Weichselian ice radiated from a centre east of Kong Karls Land. On Bj~rnOya, on the edge of the Barents Shelf, the lack of raised shorelines or glacial striae from the east indicates that the western parts of the ice sheet were thin during the Late Weichselian. The deglaciation of Edgeoya and Barentsoya occurred ca 10,300 BP as a response to calving of the marine based portion of the ice sheet. Atlantic water, which does not much influence the coasts of eastern Svalbard today, penetrated the northwestern Barents Sea shortly after the deglaciation. At that time, the coastal environment was characterised by extensive longshore sediment transport and deposition of spits at the mouths of shallow palaeo-fjords.
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| 9. |
- Möller, Per, et al.
(författare)
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Late Weichselian to early Holocene sedimentation in a steep fjord/valley setting, Visdalen, Edgeøya, eastern Svalbard: glacial deposits, alluvial/colluvial-fan deltas and spit-platforms
- 1995
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Ingår i: Polar Research. - : Norwegian Polar Institute. - 0800-0395 .- 1751-8369. ; 14:2, s. 181-203
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Tidskriftsartikel (refereegranskat)abstract
- The Visdalen valley, situated at the northwestern corner of Edgeoya, was investigated with respect to lithostratigraphy and depositional environments of the Quaternary sediments. Eight major lithostratigraphic units are recognised of which seven were deposited during the Late Weichselian to early Holocene glaciation, deglaciation and the subsequent emergence of the area, and one unit deposited prior the last glaciation. Till deposition from a west-Bowing glacier was followed by glaciomarine and later marine deposition of fine-grained sediments. Coarse-grained colluvial and alluvial-fan deltas were deposited along the mountainsides in the Visdalen palaeo-bay, and distal sediment gravity-flow deposits from these deltas were interbedded with the glaciomarine-marine sediments. A spit-platform (riegel) was built up across the Visdalen bay contemporaneously with the alluvial fan-deltas. Its formation was time-transgressive, with its highest part in the south close to the marine limit at 85 m a.s.l. and its lowest part in the north at ca 65 m a.s.l. The sediment source was alluvial and colluvial debris, which was entrained by longshore currents along the more exposed coast south of Visdalen and transported northwards to the final place of deposition. The bulk part of the riegel ridge is composed of progradational successions of steep foresets dipping towards NW, N and NE, and clearly rejects an earlier ice-contact model. Datings suggest that the fan-delta deposition and the riegel formation ended before 9,000 BP. A meltwater-fed lagoon with a highest level at >50 m a.s.l. was formed behind the riegel ridge in which; according to varve counting, glaciolacustrine sedimentation lasted more than 250 years and occurred within the time span 9,000-8,500 BP. Gradual uplift of the area resulted in drainage of the glaciolacustrine lagoon. Beachface processes and fluvial down-cutting took place during the emergence of the area.
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| 10. |
- Möller, Per
(författare)
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Subrecent moraine ridge formation on Cuff Cape, Victoria Land, Antarctica
- 1995
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Ingår i: Geografiska Annaler, Series A: Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 77:1-2, s. 83-94
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Tidskriftsartikel (refereegranskat)abstract
- A small bedrock ridge called Cuff Cape, protruding from an ice field in the inner part of Granite Harbour, Victoria Land, Antarctica, carries a system of moraine ridges. Cuff Cape was during deglaciation bounded to the south by a terrestrial, slow-retreat ice margin and towards the north and west by a faster-retreat, marine-based ice margin. Based on studies of contemporary processes along the present ice margin, sediment facies states of logged trenches and the morphology of the moraines, it can be concluded that moraines on low altitudes are composed of sediments deposited in fluvial troughs and meltwater ponds along a frontal glacier apron. The sediments were primarily deposited as debris flow diamictons, generated from melted-out sediments from basal debris bands and sorted sediments deposited as traction load and suspended load sediments in the marginal ponds. These sediments were in a frozen state later glaciotectonically thrust and stacked into moraine ridges during minor readvance stages. The largest moraine, covering a narrow retreat zone, was formed along the terrestrial ice margin by means of push and stacking of frontal apron diamictons. This moraine also carries superimposed minor ridges along its proximal slope, suggesting frequent readvance stages. Based on a survey of Cuff Cape, carried out by the English Terra Nova expedition in 1910–1913, it can be concluded that the youngest moraine has been formed since then. The absence of lichen growth on the moraines also suggests that they are of a very recent age.
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