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11.
Rapid and simple isolation of pure photosystem II core and reaction center particles from spinach 总被引:2,自引:2,他引:0
Peter J. van Leeuwen Maaike C. Nieveen Erik Jan van de Meent Jan P. Dekker Hans J. van Gorkom 《Photosynthesis research》1991,28(3):149-153
Pure and active oxygen-evolving PS II core particles containing 35 Chl per reaction center were isolated with 75% yield from spinach PS II membrane fragments by incubation with n-dodecyl--D-maltoside and a rapid one step anion-exchange separation. By Triton X-100 treatment on the column these particles could be converted with 55% yield to pure and active PS II reaction center particles, which contained 6 Chl per reaction center.Abbreviations Bis-Tris
bis[2-hydroxyethyl]imino-tris[hydroxymethyl]methane
- Chl
chlorophyll
- CP29
Chl a/b protein of 29 kDa
- Cyt b
559
cytochrome b
559
- DCBQ
2,5-dichloro-p-benzo-quinone
- LHC II
light-harvesting complex II, predominant Chl a/b protein
- MES
2-[N-Morpholino]ethanesulfonic acid
- Pheo
pheophytin
- PS H
photosystem II
- QA
bound plastoquinone, serving as the secondary electron acceptor in PS II (after Pheo)
- SDS
sodiumdodecylsulfate 相似文献
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Linkage analysis of families with hereditary retinoblastoma: nonpenetrance of mutation, revealed by combined use of markers within and flanking the RB1 gene. 总被引:8,自引:4,他引:4
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H Scheffer G J te Meerman Y C Kruize A H van den Berg D P Penninga K E Tan D J der Kinderen C H Buys 《American journal of human genetics》1989,45(2):252-260
Nonpenetrance of the inherited mutation responsible for retinoblastoma has been reported. By DNA analysis in families with hereditary retinoblastoma, it is possible to identify healthy individuals in whom the mutation is nonpenetrant. This requires the use of DNA markers both within and flanking the retinoblastoma gene. We have analyzed the segregation of several markers in 19 families (69 meioses) with hereditary retinoblastoma. In two families a carrier was identified who showed nonpenetrance of the mutation predisposing to retinoblastoma. The intragenic markers were informative in 15 pedigrees. The use of flanking markers from the same chromosomal region caused an increase of the number of informative families to 18. No crossing-over within the gene was observed. In one family an inherited deletion involving one of the RB1 alleles was detected. Our findings emphasize the use of a combination of both intragenic and flanking markers to obtain both the highest reliability of carrier detection in families with hereditary retinoblastoma and an accurate estimate of the frequency of nonpenetrance. 相似文献
15.
The at-sea distribution of seabirds and marine mammals in the eastern Barents Sea was determined using standardized transect counts during three cruises of RV“Dalnie Zelentsy” (Murmansk) in late summer 1991, 1992 and 1993. Totals of 32,268 seabirds, 485 pinnipeds, 25 cetaceans and 4 polar bears were counted during 554 half-hour counts. Numbers were converted into densities, total biomass and calculated daily food intake. Mean total food intake in kg fresh weight/km2.day was 3.1 for the entire zone and all years; fish eaters dominated the whole region, with an intake of 1.3 (mainly Brünnich’s guillemot, Uria lomvia, and harp seal, Phoca groenlandica), followed by zooplankton eaters (0.85, mainly fulmar, Fulmarus glacialis) and mixed zooplankton and fish feeders (0.75, mainly minke whale, Balaenoptera acutorostrata, and kittiwake, Rissa tridactyla). Year-to-year variations were of little importance, while geographic differences were obvious between Norwegian coastal, Atlantic and Barents Sea water masses, both quantitatively and qualitatively (relative importance of main diets). Within each zone, a strong geographic heterogeneity was noted, with high local concentrations at fronts between water masses and at ice edges. 相似文献
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Enterally administered, heme is a good source of iron in humans and other animals, but the metabolism of heme by enterocytes has not been fully characterized. Caco-2 cells in culture provide a useful model for studying cells that resemble small intestinal epithelium, both morphologically and functionally. In this paper we show that heme oxygenase, the rate-controlling enzyme of heme catabolism, is present in abundance in Caco-2 cells, and that levels of its mRNA and activity can be increased by exposure of the cells to heme or metal ions (cadmium, cobalt). Caco-2 cells also contain biliverdin reductase activity which, in the basal state, is similar to that of heme oxygenase (approximately 40 pmole of product per mg protein per minute); however, when heme oxygenase is induced, biliverdin reductase may become rate-limiting for bilirubin production.Abbreviations BVR
biliverdin reductase
- DMEM
Dulbecco's modified Eagles medium
- DMSO
dimethyl sulfoxide
- HO
heme oxygenase
- 1xSSC
a solution of 0.015 M sodium citrate/0.15 sodium chloride 相似文献
18.
Martine de Boer Maaike te Lintel Hekkert Jiang Chang Bibi S. van Thiel Leonie Martens Maxime M. Bos Marion G. J. de Kleijnen Yanto Ridwan Yanti Octavia Elza D. van Deel Lau A. Blonden Renata M. C. Brandt Sander Barnhoorn Paula K. Bautista-Niño Ilona Krabbendam-Peters Rianne Wolswinkel Banafsheh Arshi Mohsen Ghanbari Christian Kupatt Leon J. de Windt A. H. Jan Danser Ingrid van der Pluijm Carol Ann Remme Monika Stoll Joris Pothof Anton J. M. Roks Maryam Kavousi Jeroen Essers Jolanda van der Velden Jan H. J. Hoeijmakers Dirk J. Duncker 《Aging cell》2023,22(3):e13768
19.
Paul Savary Jean-Christophe Foltête Hervé Moal Gilles Vuidel Stéphane Garnier 《Molecular ecology resources》2023,23(7):1574-1588
In connectivity models, land cover types are assigned cost values characterizing their resistance to species movements. Landscape genetic methods infer these values from the relationship between genetic differentiation and cost distances. The spatial heterogeneity of population sizes, and consequently genetic drift, is rarely included in this inference although it influences genetic differentiation. Similarly, migration rates and population spatial distributions potentially influence this inference. Here, we assessed the reliability of cost value inference under several migration rates, population spatial patterns and degrees of population size heterogeneity. Additionally, we assessed whether considering intra-population variables, here using gravity models, improved the inference when drift is spatially heterogeneous. We simulated several gene flow intensities between populations with varying local sizes and spatial distributions. We then fit gravity models of genetic distances as a function of (i) the ‘true’ cost distances driving simulations or alternative cost distances, and (ii) intra-population variables (population sizes, patch areas). We determined the conditions making the identification of the ‘true’ costs possible and assessed the contribution of intra-population variables to this objective. Overall, the inference ranked cost scenarios reliably in terms of similarity with the ‘true’ scenario (cost distance Mantel correlations), but this ‘true’ scenario rarely provided the best model goodness of fit. Ranking inaccuracies and failures to identify the ‘true’ scenario were more pronounced when migration was very restricted (<4 dispersal events/generation), population sizes were most heterogeneous and some populations were spatially aggregated. In these situations, considering intra-population variables helps identify cost scenarios reliably, thereby improving cost value inference from genetic data. 相似文献
20.
Min Lu Per- Ake Albertsson G te Johansson Folke Tjerneld 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,680(1-2):65-70
Benzoyl dextran with a degree of substitution of 0.18 was synthesized by reacting dextran T500 with benzoyl chloride. A new type of aqueous two-phase system composed of benzoyl dextran as bottom phase polymer and the random copolymer of ethylene oxide and propylene oxide (Ucon 50-HB-5100) as top phase polymer has been formed. The phase diagram for the system Ucon 50-HB-5100-benzoyl dextran with a degree of substitution of 0.18 was determined at room temperature. This two-phase system has been used to purify 3-phosphoglycerate kinase from bakers' yeast. The top-phase polymer (Ucon) can be separated from target enzyme by increasing the temperature. The bottom-phase polymer (benzyol dextran) could be recovered by addition of salt. Yeast homogenate was partitioned in a primary Ucon 50-HB-5100-benzoyl dextran aqueous two-phase system. After phase separation the top phase was removed and temperature-induced phase separation was used for formation of a water phase and a Ucon-rich phase. The benzoyl dextran-enriched bottom phase from the primary system was diluted, and the polymer was separated from water by addition of Na2SO4. 相似文献