| 1. |
- Nordin, Viviann, et al.
(författare)
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Gangliosides in cerebrospinal fluid in children with autism spectrum disorders.
- 1998
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Ingår i: Developmental Medicine and Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 40:9, s. 587-594
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Tidskriftsartikel (refereegranskat)abstract
- Gangliosides are sialic acid-containing glycolipids found in all cells, especially abundant in nerve cells and mainly situated on outer-membrane surfaces. The aim of this study was to provide data on the concentration of gangliosides in the CSF of children and adolescents with autism spectrum disorders (ASD) - 66 with autistic disorder, and 19 with other autism spectrum disorders. The comparison group consisted of 29 children and adolescents, whose CSF had been sampled to exclude acute infectious CNS disorder. The concentrations of the gangliosides GM1, GD1a, GD1b, and GT1b were determined using a microimmunoaffinity technique. The ASD group had a significantly higher concentration of ganglioside GM1 compared with the comparison group. The GM1 increase could not be explained as secondary to other clinical factors. Mean ganglioside levels did not differentiate subgroups with autistic disorder and those with a more atypical clinical picture, nor subgroups with known medical disorders and those with idiopathic autism. Altered patterns of gangliosides in the CNS might reflect important correlates of pathogenesis in autism.
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| 2. |
- Näsholm, Torgny, et al.
(författare)
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Boreal forest plants take up organic nitrogen
- 1998
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 392:6679, s. 914-916
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Plant growth in the boreal forest, the largest terrestrial biome, is generally limited by the availability of nitrogen. The presumed cause of this limitation is slow mineralization of soil organic nitrogen1,2. Here we demonstrate, to our knowledge for the first time, the uptake of organic nitrogen in the field by the trees Pinus sylvestris and Picea abies, the dwarf shrub Vaccinium myrtillus and the grass Deschampsia flexuosa. These results show that these plants, irrespective of their different types of root–fungal associations (mycorrhiza), bypass nitrogen mineralization. A trace of the amino acid glycine, labelled with the stable isotopes 13C and 15N, was injected into the organic (mor) layer of an old successional boreal coniferous forest. Ratios of 13C:15N in the roots showed that at least 91, 64 and 42% of the nitrogen from the absorbed glycine was taken up in intact glycine by the dwarf shrub, the grass and the trees, respectively. Rates of glycine uptake were similar to those of 15N-ammonium. Our data indicate that organic nitrogen is important for these different plants, even when they are competing with each other and with non-symbiotic microorganisms. This has major implications for our understanding of the effects of nitrogen deposition, global warming and intensified forestry.
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