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1.
Abundance and distribution of cod Gadus morhua in various size intervals and age groups between 2000 and 2005 were followed in coastal trawl surveys. In spite of a reduction in fishing pressure in recent years and high cod recruitment in the Skagerrak region in 2001 and 2003, no recovery could be evidenced. The survey data clearly showed that low cod density areas were not recolonized, even though abundance of juvenile cod remained high for about a year after the recruitment episodes. Increased abundance of fish >400 mm total length was only discernible at some scattered locations where other studies also have suggested local populations still to be present. The intermittent high recruitment has been linked to an inflow of egg and larvae from the North Sea, a theory which also has gained support from genetic studies. It was thus argued that the disappearance of the juvenile cod from the inshore is an effect of a migratory behaviour; the fish of offshore origin eventually leave the coast for the open Skagerrak or the North Sea. These findings support a view on cod populations as essentially behavioural entities, whereas dispersal of early life stages may be less important as a structuring mechanism. 相似文献
2.
The use of biochemical markers, serotype and fimbriation in the detection of Escherichia coli clones 总被引:3,自引:0,他引:3
A Brauner J M Boeufgras S H Jacobson B Kaijser G K?llenius S B Svenson B Wretlind 《Journal of general microbiology》1987,133(10):2825-2834
Biochemical reactions, O and K serotypes and presence of P-fimbriae were analysed in 116 Escherichia coli strains isolated in blood cultures from patients with bacteraemia and in 99 faecal strains isolated from healthy individuals. By using biochemical typing, the strains could be grouped into six main clusters with similarity index less than 0.8 (Gower, 1971) and altogether 16 subclusters with similarity index 0.82-0.89. The most discriminating tests between the clusters were fermentation of D-tagatose, saccharose, salicin and sorbose. No single biochemical property could differentiate bacteraemic isolates from faecal strains, although strains isolated from blood were significantly more often found in certain subclusters, whereas other subclusters contained mainly control strains. Bacteraemic strains possessed P-fimbriae more often, especially strains isolated from patients with E. coli in the urine concomitantly with bacteraemia. Equally, no single reaction could separate P-fimbriated from non-P-fimbriated strains. D-Tagatose was fermented more often by the P-fimbriated strains; on the other hand, melibiose and lactose fermentation tests were less often positive. Certain O serotypes (O1, O4, O6, O7, O18 and O25) were more common among bacteraemic isolates than controls. K serotypes such as K1, K5 and K52 were also more frequent among blood isolates. We conclude that a combination of biochemical tests, fimbriation and serotyping might be used to identify potentially pathogenic clusters of E. coli. 相似文献
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5.
Measurement of cytokine antibodies. Test development 总被引:1,自引:0,他引:1
Several assays have been used for detection of antibodies against cytokines. The choice of assay is greatly dependent on the
intended goal, e.g. detection of naturally occurring antibodies or therapy induced antibodies. The different assays can be
grouped in 2 categories. The interference or indirect assays are based on the detection of the test sample interference with
the biological activity, with detection of the cytokine in EIA or with binding to cellular receptors. In direct assays cytokine
antibodies are detected by binding to solid phase fixed cytokines, followed by incubation with a secondary enzyme-labelled
anti-human Ig antibody or by binding to125I-labelled cytokines in RIA. 相似文献
6.
A new homeobox-leucine zipper gene from Arabidopsis thaliana 总被引:3,自引:0,他引:3
Jim Mattsson Eva Söderman Marie Svenson Chumpol Borkird Peter Engström 《Plant molecular biology》1992,18(5):1019-1022
We have isolated a homeobox-containing gene from Arabidopsis thaliana using a degenerate oligonucleotide probe corresponding to the most conserved region of the homeodomain. This strategy has been used previously to isolate homeobox-containing genes from Caenorhabditis, and recently from A. thaliana. The Arabidopsis genes have an unusual structure in that they have a leucine zipper motif adjacent to the carboxy terminal region of the homeo domain, a feature not found in homeobox-containing genes isolated from animals. We report the isolation and primary structure of a new member of this Arabidopsis homeobox-leucine zipper gene family. This new member has the homeodomain and leucine-zipper motif similar to the two genes previously identified, but differs from these genes in the part corresponding to the carboxy terminus of the polypeptide, as well as in size and isoelectric point of the protein. 相似文献
7.
To study the mechanism by which bacteriophage T4 inhibits the synthesis of inducible host enzymes we measured the formation of beta-galactosidase from preformed lac mRNA. Beta-Galactosidase was induced with isopropyl-beta-D-thiogalactopyranoside in the presence of 7-azatryptophan, a tryptophan analogue that is incorporated into proteins and renders the beta-galactosidase formed inactive. The accumulated las mRNA was measured by capacity to form active beta-galactosidase after a chase of the analogue with excess tryptophan. After T4 infection the ability to form beta-galactosidase from the preformed lac mRNA was rapidly lost even when T4 infection took place in the presence of rifampin. This restriction was dependent on the multiplicity of infection. At a multiplicity of infection of 8.6, 90% of the ability to express preformed lac mRNA was lost within 30 s. The kinetics of cessation of beta-galactosidase synthesis after T4 infection indicate that infection blocks initiation of lac mRNA translation. 相似文献
8.
Amine oxidase was purified from bovine serum by affinity chromatography on aminohexyl substituted Sepharose. The enzyme was adsorbed on the chromatographic support in a suspension of aminohexyl Sepharose in diluted serum. After thorough washing with buffer, the gel was packed in a column and the enzyme eluted with 10 mM octylamine. Using this procedure it was possible to obtain apparently homogenous amine oxidase in a single-step procedure. The specific enzyme activity was 0.14 μoles benzaldehyde formed per minute at 25°C per mg enzyme protein. Based on the activity of amine oxidase in serum, the yield of enzyme was 64 %. 相似文献
9.
Oleg V. Kovalenko Andrea Olland Nicole Piché-Nicholas Adarsh Godbole Daniel King Kristine Svenson Valerie Calabro Mischa R. Müller Caroline J. Barelle William Somers Davinder S. Gill Lidia Mosyak Lioudmila Tchistiakova 《The Journal of biological chemistry》2013,288(24):17408-17419
The immunoglobulin new antigen receptors (IgNARs) are a class of Ig-like molecules of the shark immune system that exist as heavy chain-only homodimers and bind antigens by their single domain variable regions (V-NARs). Following shark immunization and/or in vitro selection, V-NARs can be generated as soluble, stable, and specific high affinity monomeric binding proteins of ∼12 kDa. We have previously isolated a V-NAR from an immunized spiny dogfish shark, named E06, that binds specifically and with high affinity to human, mouse, and rat serum albumins. Humanization of E06 was carried out by converting over 60% of non-complementarity-determining region residues to those of a human germ line Vκ1 sequence, DPK9. The resulting huE06 molecules have largely retained the specificity and affinity of antigen binding of the parental V-NAR. Crystal structures of the shark E06 and its humanized variant (huE06 v1.1) in complex with human serum albumin (HSA) were determined at 3- and 2.3-Å resolution, respectively. The huE06 v1.1 molecule retained all but one amino acid residues involved in the binding site for HSA. Structural analysis of these V-NARs has revealed an unusual variable domain-antigen interaction. E06 interacts with HSA in an atypical mode that utilizes extensive framework contacts in addition to complementarity-determining regions that has not been seen previously in V-NARs. On the basis of the structure, the roles of various elements of the molecule are described with respect to antigen binding and V-NAR stability. This information broadens the general understanding of antigen recognition and provides a framework for further design and humanization of shark IgNARs. 相似文献
10.
Koivula T Ekman M Leitner T Löfdahl S Ghebremicahel S Mostowy S Behr MA Svenson SB Källenius G 《Microbes and infection / Institut Pasteur》2004,6(3):272-278
In a previous study of Mycobacterium tuberculosis complex isolates from Guinea-Bissau in West Africa, we identified a unique group of strains, designated here as the Guinea-Bissau family of strains, which, although genotypically closely related, phenotypically demonstrated a considerable heterogeneity. We conducted here a detailed genotypic analysis of a subset (n = 35) of these isolates. Based on the data obtained, and by comparison of known corresponding genes in mycobacteria outside the M. tuberculosis complex, we propose that the Guinea-Bissau strains belong to a unique branch of the M. tuberculosis complex tree in between classical M. tuberculosis and classical M. bovis. These observations are discussed in their significance in M. tuberculosis complex classification. 相似文献