| 481. |
- 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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| 482. |
- 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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| 483. |
- 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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| 484. |
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| 485. |
- 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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| 486. |
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| 487. |
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| 488. |
- Tu, Qiang, et al.
(författare)
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Determination of mercury species by capillary zone electrophoresis-inductively coupled plasma mass spectrometry: a comparison of two spray chamber-nebulizer combinations
- 2000
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Ingår i: ANALYST. - : Royal Society of Chemistry (RSC). ; 125:4, s. 705-710
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Tidskriftsartikel (refereegranskat)abstract
- A method based on capillary zone electrophoresis (CZE) separation and inductively coupled plasma mass spectrometry (ICP-MS) detection is presented for the determination of methylmercury and inorganic mercury. The CZE conditions were optimised with respect to the flow rates for nebulizer gas and sheath solution, concentration of electrolyte and applied voltage. The performances of two different sample injection systems were compared. A standard cross-flow nebulizer with a Scott spray chamber offered a shorter analysis time, better resolution and ruggedness, while a micro-concentric nebulizer (MCN-100) with a cyclone spray chamber improved the detection limit by a factor of 11 for CH3Hg+ and a factor of 19 for Hg2+. With the MCN-100,the detection limits were 13.6 ng ml(-1) for CH3Hg+ and 6.0 ng ml(-1) for Hg2+, corresponding to absolute detection limits of 2.3 pg and 1.0 pg, respectively, for a hydrodynamic injection of 170 nl. The method was tested using three biological certified reference materials with a certified methylmercury content. The pre-treatment of biological samples involves only digestion and pH adjustment, without the need for derivatization or extraction, so that potential errors involved in these usually time-consuming steps can be avoided.
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| 489. |
- Tu, Qiang, et al.
(författare)
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Rapid determination of methylmercury in biological materials by GC-MIP-AES or GC-ICP-MS following simultaneous ultrasonic-assisted in situ ethylation and solvent extraction
- 2000
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Ingår i: JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY. - : Royal Society of Chemistry (RSC). - 0267-9477 .- 1364-5544. ; 15:12, s. 1583-8
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Tidskriftsartikel (refereegranskat)abstract
- A simple and rapid sample pre-treatment procedure was developed for the determination of methylmercury in biological materials. The procedure is based on acid leaching (5 min) of sample materials followed by simultaneous in situ derivatisation and extraction (40 min) in the presence of sodium tetraethylborate and nonane, buffered at pH 7.0, in an ultrasonic held. The nonane phase with an overall average recovery of methylmercury higher than 90% was analysed by gas chromatography (GC) coupled to microwave induced plasma atomic emission spectrometry (MIP-AES) or inductively coupled plasma mass spectrometry (ICP-MS). Detection limits (as Hg), based on three times the standard deviation of a standard solution, were 4.4 ng g(-1) for GC-MIP-AES and 2.6 ng g(-1) for GC-ICP-MS. No artefact formation of methylmercury during sample pretreatment was observed following the addition of a (201)Hg2(+) isotope standard. The method was validated by the analysis of three biological certified reference materials and applied to the determination of methylmercury in a fish sample.
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| 490. |
- Turchin, Peter, et al.
(författare)
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Are lemmings prey or predators?
- 2000
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Ingår i: Nature. - 0028-0836. ; 405, s. 562-565
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Tidskriftsartikel (refereegranskat)
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