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- Lindström, K, et al.
(författare)
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Non-acid glycosphingolipid expression in plasma of an A1 Le(a-b+) secretor human individual: identification of an ALeb heptaglycosylceramide as major blood group component.
- 1992
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Ingår i: Journal of biochemistry. - 0021-924X. ; 111:3, s. 337-45
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Tidskriftsartikel (refereegranskat)abstract
- Total non-acid glycosphingolipids were isolated from plasma of an A1 Le(a-b+) secretor individual with Refsum's disease (phytanic acid storage disease). The glycolipids were separated into 11 fractions by open column chromatography and by HPLC. The fractions were analyzed by thin-layer chromatography and tested for different blood group A activities as well as blood group Le(a )and Leb activity. The fractions were structurally characterized by proton NMR spectroscopy and FAB mass spectrometry and in selected cases by EI mass spectrometry of the permethylated and permethylated-reduced derivatives. Degradation analysis was performed on partially permethylated or permethylated-reduced alditol acetates. The dominating blood group compound was found to be a blood group A active type 1 chain difucosylheptaglycosylceramide. Other blood group compounds were identified as a blood group A active type 1 chain monofucosylhexaglycosylceramide, a blood group Leb hexaglycosylceramide, a blood group H active type 1 chain pentaglycosylceramide, and a globotetraosylceramide (the P-antigen). The presence of a Le(a) glycosphingolipid and blood group A type 3/4 chain structures were also found by immunostaining. Glucosyl-, lactosyl-, and globotriaosylceramides were the dominating short chain compounds. The amount of phytanic acid incorporated into the monoglycosylceramide fraction was found to be less than 5% of the fatty acids.
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- Lindström, Åke, et al.
(författare)
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Asymmetric contests over resources for survival and migration: a field experiment with bluethroats
- 1990
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Ingår i: Animal Behaviour. - 1095-8282. ; 40:3, s. 453-461
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Tidskriftsartikel (refereegranskat)abstract
- The relative importance of prior occupancy and of asymmetries in both value of winning and in resource-holding potential for the outcome of animal contests was tested. Bluethroats, Luscinia s. svecica, were offered food ad libitum in the field. Prior to migration, at a moulting site, their weight increased rapidly and peaked after a few days. Lean birds won significantly more interactions than fat birds, probably owing to higher motivation to fight for the food. Dominance between individuals shifted and was not correlated with size or prior occupancy. During the subsequent migration, at a stopover site, the bluethroats gained weight throughout their stay. Dominance between individuals was constant and positively correlated with size, whereas fat reserves and prior occupancy had no effect on contest resolution. Fat deposition rates were positively correlated with dominance status. The different dominance patterns are explained in terms of different gain curves of fat for birds putting on fat for survival and migration, respectively. Though prior occupancy had no general effect on dominance patterns, such an uncorrelated asymmetry may have been used to settle single contests between fat birds at the moulting site. The fact that dominance (acting through differences in size) influences fat deposition rates may be important for the spatial and temporal pattern of migration in birds that compete for resources at stopover sites.
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