| 1. |
- Carrino, David A, et al.
(författare)
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Age-related changes in the proteoglycans of human skin - Specific cleavage of decorin to yield a major catabolic fragment in adult skin
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:19, s. 17566-17572
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Tidskriftsartikel (refereegranskat)abstract
- Dramatic changes occur in skin as a function of age, including changes in morphology, physiology, and mechanical properties. Changes in extracellular matrix molecules also occur, and these changes likely contribute to the overall age-related changes in the physical properties of skin. The major proteoglycans detected in extracts of human skin are decorin and versican. In addition, adult human skin contains a truncated form of decorin, whereas fetal skin contains virtually undetectable levels of this truncated decorin. Analysis of this molecule, herein referred to as decorunt, indicates that it is a catabolic fragment of decorin rather than a splice variant. With antibody probes to the core protein, decorunt is found to lack the carboxyl-terminal portion of decorin. Further analysis by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry shows that the carboxyl terminus of decorunt is at Phe(170) of decorin. This result indicates that decorunt represents the amino-terminal 43% of the mature decorin molecule. Such a structure is inconsistent with alternative splicing of decorin and suggests that decorunt is a catabolic fragment of decorin. A neoepitope antiserum, anti-VRKVTF, was generated against the carboxyl terminus of decorunt. This antiserum does not recognize intact decorin in any skin proteoglycan sample tested on immunoblots but recognizes every sample of decorunt tested. The results with anti-VRKVTF confirm the identification of the carboxyl terminus of decorunt. Analysis of collagen binding by surface plasmon resonance indicates that the affinity of decorunt for type I collagen is 100-fold less than that of decorin. This observation correlates with the structural analysis of decorunt, in that it lacks regions of decorin previously shown to be important for interaction with type I collagen. The detection of a catabolic fragment of decorin suggests the existence of a specific catabolic pathway for this proteoglycan. Because of the capacity of decorin to influence collagen fibrillogenesis, catabolism of decorin may have important functional implications with respect to the dermal collagen network.
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| 2. |
- Lund-Hansen, L. C., et al.
(författare)
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Summer meltwater and spring sea ice primary production, light climate and nutrients in an Arctic estuary, Kangedussuaq, west Greenland
- 2018
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Ingår i: Arctic Antarctic and Alpine Research. - : Informa UK Limited. - 1523-0430 .- 1938-4246. ; 50:1
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Tidskriftsartikel (refereegranskat)abstract
- The estuary is dominated by sea ice and snow cover from winter to spring, and a highly turbid meltwater plume during summer. The aims were to quantify the variability in optical conditions, inorganic nutrients, and primary production between these two extremes, and identify the drivers of variability. Data were obtained during a summer cruise along a transect in the estuary in August 2007, and a spring campaign on the ice in March 2011. The study comprises conductivity, temperature, and depth (CTD), K-d (PAR), K-d (A), PAR transmittance, photic depth, chl-a, nutrients (NO3, NO2, NH3 , PO4, and SiO2), primary production, and sediment concentrations. PAR transmittance varied between 5% below snow and ice and 85% in clear water with 44% in turbid meltwater. Primary production rates were similar below the ice in March (76.8 mg C m(-2) d(-1)) and in the highly turbid meltwater in August (94.8 mg C m(-2) d(-1)), but higher (246.6 mg C m(-2) d(-1)) at the mouth of the fjord. Meltwater inflow was the main driver of variability during summer and the snow and sea ice during spring. Under-ice primary production will increase three-fold with less snow on the sea ice, and the higher meltwater turbidity with increased melting of glacial ice and runoff will only reduce primary production slightly.
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