| 491. |
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| 492. |
- Suominen, O, et al.
(författare)
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Impacts of semi-domesticated reindeer on structure of tundra and forest communities in Fennoscandia : a review
- 2000
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Ingår i: Annales Zoologici Fennici. - 0003-455X .- 1797-2450. ; 37:4, s. 233-249
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Tidskriftsartikel (refereegranskat)abstract
- Grazing and trampling by semi-domesticated reindeer are important factors controlling vegetation in northern Fennoscandia. In this article we review Nordic studies on the effects of reindeer on vegetation and animal communities. The studies have shown clear effects on vegetation, especially on Cladina lichen dominated sites. Cladina is the main forage of reindeer during winter and dominates climax vegetation in dry site types in the absence of reindeer. Reindeer can even affect galling and ground-dwelling invertebrates. Due to the special relationship between reindeer and Cladina majority of the research has concentrated on winter grazing on Cladina, but there are some studies of summer grazing which have also shown substantial changes in vegetation. Reindeer grazing increases richness and diversity of vegetation and invertebrate assemblages in most cases, but this influence depends on site type and grazing intensity. The enriching effect seems to be strongest at moderate grazing intensity.
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| 493. |
- Svens, Christina
(författare)
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Genusgestaltning
- 2000
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Ingår i: Hjärnstorm. - 0348-6958. ; :70, s. 11-15
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 494. |
- Svensson, Anette, et al.
(författare)
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Preparation of fluorinated linkers : Use of F-19 NMR spectroscopy to establish conditions for solid-phase synthesis of pilicide libraries
- 2000
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Ingår i: Journal of Combinatorial Chemistry. - : American Chemical Society (ACS). - 1520-4766 .- 1520-4774. ; 2:736-48
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Tidskriftsartikel (refereegranskat)abstract
- Three fluorinated linkers which are analogues of linkers commonly used in solid-phase peptide synthesis have been prepared. One of the linkers was used in combination with gel-phase F-19 NMR spectroscopy to develop conditions for solid-phase synthesis of two libraries of pilicides, i.e. compounds designed to inhibit assembly of adhesive pill in uropathogenic Escherichia coli. Attachment to and cleavage from the linker could be monitored based on the chemical shift of the fluorine atom of the linker. In addition, use of the linker as internal standard allowed quantification and optimization of reactions occurring further away from the linker when fluorinated building blocks were employed. Importantly, high-quality F-19 NMR spectra were obtained for compounds linked to a TentaGel resin in a standard NMR tube using an ordinary NMR instrument.
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| 495. |
- Söderman, Kerstin, et al.
(författare)
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Bone mass and muscle strength in young female soccer players.
- 2000
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 67:4, s. 297-303
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Tidskriftsartikel (refereegranskat)abstract
- In this cross-sectional study, bone mass and muscle strength of the thigh were investigated in 51 female soccer players, age 16.3 +/- 0. 3 years, who had been playing soccer for 8.1 +/- 2.1 years and were at the time of the study in soccer training for 5.0 +/- 1.7 hours/week. They were compared with 41 nonactive females, age 16.2 +/- 1.3 years. The groups were matched according to age, weight, and height. Areal bone mineral density (BMD) was measured of the total body, head, lumbar spine, femoral neck, Ward's triangle, and the greater trochanter using dual energy X-ray absorptiometry (DXA). Isokinetic muscle strength of the quadriceps and hamstrings muscles was measured using an isokinetic dynamometer. Compared with the nonactives, the soccer players had significantly higher BMD of the total body (2.7%), lumbar spine (6.1%), the dominant and nondominant hip (all sites). The largest differences were found in the greater trochanter on both sides (dominant, 16.5%, nondominant, 14.8%). The soccer players had significantly higher concentric and eccentric peak torque of the thigh muscles. In the soccer group, there was only a positive association between thigh muscle strength and BMD of the adjacent hip, and in the nonactive group there were several positive associations between muscle strength and BMD. However, when adjusting for the variation in weight and height all these associations became nonsignificant. Using multiple linear regression, the type of activity (soccer player, nonactive) independently predicted BMD of all dominant hip sites (beta = 0.32-0.48, P < 0.01). No other variable was found to independently predict BMD of any site. In the younger subjects ( 16 years) the soccer players had significantly higher BMD in all measured sites except for the nonweight-bearing head. The differences in muscle strength between soccer players and nonactives were already seen in the young age group. In conclusion, girls who train and play soccer in adolescence have a higher bone mass in the hip and lumbar spine, and a higher muscle strength of the thigh compared with nonactive controls, indicating a site-specific skeletal response of weight-bearing and impact-loadng acting on the skeleton. The differences in bone mass were already apparent in early adolescence, but became more pronounced in late adolescence, probably explained by a longer exposure to soccer training with time. Our results also indicate that muscle strength in itself might not be of decisive importance for bone mass in the hip of adolescent females.
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| 496. |
- Söderström, Tor
(författare)
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Varför gym?
- 2000
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Ingår i: Svensk idrottsforskning. ; :4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 497. |
- Tavares, F, et al.
(författare)
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A simple, rapid and non-destructive procedure to extract cell wall-associated proteins from Frankia
- 2000
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Ingår i: Journal of Microbiological Methods. - 0167-7012 .- 1872-8359. ; 39:2, s. 171-178
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Tidskriftsartikel (refereegranskat)abstract
- A simple cell fractionation procedure was developed to extract cell wall-associated proteins from the nitrogen-fixing actinomycete Frankia. The method was based on washing Frankia mycelia in 62.5 mM Tris-HCl (pH 6.8) buffer supplemented with 0.1% Triton X-100 as solubilizing agent. Cell wall-associated proteins were efficiently extracted in less than 10 min, recovering approximately 94.5+/-7.44 pg protein per extraction procedure from exponentially growing cells, corresponding to 50 ml of culture. The amount of cell lysis occurring during the cell wall extraction was estimated to be 1.50+/-0.51%. Three peptidoglycan hydrolases with apparent molecular masses of 4.7, 12.1, and 17.8 kDa were detected by zymography in the cell wall-associated protein fraction. On the contrary, no cell wall lytic enzyme was detected in the cytoplasmic protein fraction. These results indicate that the present method enables a specific extraction of cell wall-associated proteins. Moreover, fluorescein isothiocyanate (FITC) labelling of the cell surface proteins showed an efficient removal of cell wall-associated proteins. Growth of the treated Frankia cells (i.e. cells from which the cell wall-associated proteins were removed) in semi-solid media suggested that these cells were still viable. This technique is of importance for functionality studies of cell wall-associated proteins, particularly for bacteria where traditional cell fractionation methods are difficult to be applied. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 498. |
- Tay, GK, et al.
(författare)
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PERB11 (MIC) : a polymorphic MHC gene is expressed in skin and single nucleotide polymorphisms are associated with psoriasis.
- 2000
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Ingår i: Clinical and Experimental Immunology. - : John Wiley & Sons. - 0009-9104 .- 1365-2249. ; 119:3, s. 553-558
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Tidskriftsartikel (refereegranskat)abstract
- The susceptibility genes for psoriasis remain to be identified. At least one of these must be in the major histocompatibility complex (MHC) to explain associations with alleles at human leucocyte antigen (HLA)-A, -B, -C, -DR, -DQ and C4. In fact, most of these alleles are components of just two ancestral haplotypes (AHs) designated 13.1 and 57.1. Although relevant MHC gene(s) could be within a region of at least 4 Mb, most studies have favoured the area near HLA-B and -C. This region contains a large number of non-HLA genes, many of which are duplicated and polymorphic. Members of one such gene family, PERB11.1 and PERB11.2, are expressed in the skin and are encoded in the region between tumour necrosis factor and HLA-B. To investigate the relationship of PERB11.1 alleles to psoriasis, sequence based typing was performed on 97 patients classified according to age of onset and family history. The frequency of the PERB11.1*06 allele is 44% in type I psoriasis but only 7% in controls (Pc = 0.003 by Fisher's exact test, two-tailed). The major determinant of this association is a single nucleotide polymorphism (SNP) within intron 4. In normal and affected skin, expression of PERB11 is mainly in the basal layer of the epidermis including ducts and follicles. PERB11 is also present in the upper keratin layers but there is relative deficiency in the intermediate layers. These findings suggest a possible role for PERB11 and other MHC genes in the pathogenesis of psoriasis.
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| 499. |
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| 500. |
- Timby, Niklas, et al.
(författare)
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Gamma-hydroxybutyrate associated deaths.
- 2000
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Ingår i: American Journal of Medicine. - 0002-9343. ; 108:6, s. 518-9
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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