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- Schalén, C, et al.
(author)
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Demonstration of separate receptors for human IgA and IgG in group A streptococci type 4. Separation of the solubilized receptors from group- and type-specific antigens, lipoteichoic acid and peptidoglycan
- 1980
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In: Acta Pathologica et Microbiologica Scandinavica. Section C, Immunology. - : Wiley. - 0304-1328. ; 88:2, s. 77-82
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Journal article (peer-reviewed)abstract
- The alkaline extract of group A streptococci type 4 was separated by electrophoresis and diffused against 27 normal human sera. One of the precipitates appeared with 85% of the sear. Addition of purified IgA myeloma protein or sera containing IgA M-components to the extract changed the electrophoretic mobility of the precipitate anodically. Purified IgG Fc-fragments or sera containing IgG M-component did not affect the mobility of the precipitate. It was concluded that this precipitate contained the streptococcal receptor for human IgA. A non-precipitating IgG Fc-receptor, with agglutinating capacity for cells coated with human IgG1 but not IgG3, was localized by preparative electrophoresis to the same electrophoretic region as the IgA receptor. The mobility of the IgG receptor remained unaltered on addition of IgA myeloma protein permitting a separation of the two receptors by preparative electrophoresis. The receptors were distinct from the group specific carbohydrate, peptidoglycan and lipoteicholic acid. No M antigen or opacity factor were demonstrated in the extract.
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- Öquist, G., et al.
(author)
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Chlorophyll a fluorescence an alternative method for estimating primary production
- 1982
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In: Marine Biology. - 1230-7688. ; 68:1, s. 71-75
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Journal article (peer-reviewed)abstract
- The in vivo chlorophyll a fluorescence index (F+DcM u-F-DcMu/F+DcMU) of natural waters was compared to the 14C-determined primary production, and the fluorescence intensity in the presence of 3-(3,4-dichlorophenyl)-l,l-dimethylurea (F + DCM~) was studied as a function of extracted and spectrophotometrically determined chlorophyll concentrations. Samples were taken every second week from May through October, 1979, at the station "Systrarna" situated in a coastal area of the Bottnian Sea. In addition, samples from the Archipelago Sea of the Baltic were collected on board the Finnish research vessel R/S "Aranda" during the September cruise 1979. The correlations between the fluorescence index and the 14C-determined primary production and between F+DcMu and total chlorophyll concentration were good when samples taken over short time intervals were compared. The shortcomings of both the fluorescence and the 14C methods are discussed. It is concluded that the fluorescence method is useful if it is desirable to follow with high time resolution any changes in the potential for photosynthesis (or pirmary production) in a water mass over relatively short time periods; e.g. during an algal bloom. The fluorescence method can furthermore be technically developed for automatic monitoring with a high time resolution. Efforts are being made in our laboratory to develop the method further to give information about the in situ rates of photosynthesis rather than the potential for photosynthesis in a phytoplankton population.
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