| 1. |
- Fuzzi, S., et al.
(författare)
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The Po Valley Fog Experiment 1989
- 1992
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Ingår i: Tellus. Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 0280-6509. ; 44:5, s. 448-468
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Tidskriftsartikel (refereegranskat)abstract
- An outline is presented here of the Po Valley Fog Experiment 1989, carried out within the EUROTRAC‐GCE project. This experiment is a joint effort by several European research groups from 5 countries. The physical and chemical behaviour of the fog multiphase system was studied experimentally following the temporal evolution of the relevant chemical species in the different phases (gas, droplet, interstitial aerosol) and the evolution of micrometeorological and microphysical conditions, from the pre‐fog situation through the whole fog evolution, to the post‐fog period. Some general results, useful for describing the general features of the fog system, are presented here, while specific scientific questions on the different processes taking place within the system itself will be addressed in other companion papers of this same issue.
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| 2. |
- Carlstedt, I, et al.
(författare)
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Characterization of two different glycosylated domains from the insoluble mucin complex of rat small intestine.
- 1993
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Ingår i: The Journal of biological chemistry. - 0021-9258. ; 268:25, s. 18771-81
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Tidskriftsartikel (refereegranskat)abstract
- The highly glycosylated domains of rat small intestinal mucins were isolated after reduction and trypsin digestion and separated into two populations (A and B) by gel chromatography. The molecular mass values were 650 and 335 kDa, respectively, and the relative yields suggest that the two glycopeptides occur in equimolar proportions. Electron microscopy revealed linear structures with weight average lengths of 230 nm (A) and 110 nm (B) corresponding to a mass/unit length of about 3 kDa/nm. The protein cores (17-19%) contain large amounts of threonine (over 40%), serine (17-24%), and proline (18-19%). Carbohydrate and sulfate account for approximately 80 and 0.5%, respectively, and gas chromatography-mass spectrometry showed that the patterns of neutral and sialic acid-containing glycans are very similar in the two glycopeptides. Both contain a significant amount (7-10 mol %) of single GalNAc residues, the average oligosaccharide is about 4 sugar residues long, and the largest species observed are heptasaccharides. The major neutral and sialic acid-containing oligosaccharides are Fuc1-2Gal1-3GalNAcol and GlcNAc1-6(NeuGc2-Gal1-3)GalNAcol, respectively. Sialic acid is present as both N-acetyl- and N-glycoloyl-neuraminic acid. Repeated extractions of the tissue with guanidinium chloride left approximately 80% of the mucus glycoproteins as an insoluble glycoprotein complex whereas exposure to dithiothreitol or high speed homogenization accomplished complete solubilization. The "subunits" obtained after reduction with dithiothreitol are larger than glycopeptides A and B, and fragments corresponding in size to the latter are obtained after cleavage with trypsin. Most of the mucins from rat small intestine thus occurs as an insoluble glycoprotein complex composed of subunits joined with disulfide bonds. The subunits contain two highly glycosylated regions with different lengths substituted with very similar oligosaccharides.
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| 3. |
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| 4. |
- Bergström, S, et al.
(författare)
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Cloning and sequencing of human kappa-casein cDNA.
- 1992
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Ingår i: DNA Sequence. - 1042-5179 .- 1029-2365. ; 3:4, s. 245-6
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Tidskriftsartikel (refereegranskat)abstract
- A cDNA encoding kappa-casein of human milk was cloned and sequenced. The kappa-casein cDNA was isolated from a lambda gt11 library generated from mRNA prepared from a mammary gland biopsy obtained from a lactating woman. The library was screened with polyclonal rabbit antibodies raised against purified native kappa-casein. The obtained nucleotide sequence contained an ORF sufficient to encode the entire amino acid sequence of a kappa-casein precursor protein consisting of 182 amino acids. This includes a tentative signal peptide of 20 amino acids and a processed protein of 162 amino acids.
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| 5. |
- Hansson, B. S., et al.
(författare)
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Correlation between dendrite diameter and action potential amplitude in sex pheromone specific receptor neurons in male Ostrinia nubilalis (Lepidoptera: Pyralidae)
- 1994
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Ingår i: Tissue and Cell. - : Elsevier BV. - 0040-8166. ; 26:4, s. 503-512
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Tidskriftsartikel (refereegranskat)abstract
- Outer dendritic segments of olfactory receptor neurons tuned to sex pheromone components were measured morphometrically on the antenna of male European corn borers. Ostrinia nubilalis, to determine if a correlation exists between the diameter of the outer dendritic segment and the spike amplitude. The olfactory sensilla investigated each contained three receptor cells. Two cells were each specific for one of the two pheromone components, (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (E)-11-tetradecenyl acetate (E11-14:OAc). Two strains of cornborers (Z and E) differ as to which of the two pheromone components is the main one. In both strains a large difference could be observed between the spike amplitudes elicited in the receptor cells by the two pheromone components, the main component always eliciting the large spike. In F1-hybrids (EZ) of these two strains, producing both pheromone components in similar quantities, the spike amplitudes were equal in the two pheromone-specific receptor cells. The third cell responded specifically to a behavioural antagonist. (Z)-9-tetradecenyl acetate (Z9-14:OAc) in both the parental and hybrid strains, and always showed the smallest spike amplitude. In a morphometric study, the outer dendritic segments were shown to differ more in diameter between the largest and second largest cell in the two parental strains than in the hybrid strain, while the smallest diameter cell did not differ between the different strains. These results imply that receptor cells with larger diameter produce spikes with greater amplitude. The data also show that all three types of receptor neurons display outer dendritic segments with strong variation in the diameter along the length of the segment, and with a pronounced taper towards the tip.
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| 6. |
- Hansson, L, et al.
(författare)
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Expression of human milk beta-casein in Escherichia coli : comparison of recombinant protein with native isoforms.
- 1993
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 4:5, s. 373-81
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Tidskriftsartikel (refereegranskat)abstract
- Studies on physiological function and on structure-function relationships of human milk beta-casein have been limited. In this study, we have introduced the human beta-casein cDNA into vectors designed for expression in Escherichia coli. The inducible T7-based expression system resulted in high-level expression of recombinant beta-casein. The recombinant beta-casein, localized intracellularly in E. coli, was purified to homogeneity and compared with purified native beta-casein, in particular with respect to phosphorylation. The E. coli-produced beta-casein was found to comigrate with the full-length, nonphosphorylated native human beta-casein isoform on SDS-PAGE. An N-terminal peptide containing all tentative phosphorylation sites was isolated from the recombinant protein and analyzed by mass spectrometry. The molecular mass as well as the migration of this peptide on reversed-phase chromatography confirmed that it was unphosphorylated.
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| 7. |
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| 8. |
- Hansson, T., et al.
(författare)
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High temperature fracture of a SiC whisker-reinforced alumina in air and vacuum
- 1994
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Ingår i: Journal of the European Ceramic Society. - : Elsevier BV. - 0955-2219 .- 1873-619X. ; 13:5, s. 427-436
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Tidskriftsartikel (refereegranskat)abstract
- The fracture behaviour of a SiCw/alumina composite was studied between room temperature and 1320°C in vacuum by four-point bend testing of specimens pre-cracked by bridge indentation. The results are compared to those of earlier work on a similar material in air. In vacuum, the composite begins to exhibit stable crack growth (SCG) and increasing apparent toughness at about 1100°C. Between 1100 and 1320°C, the extent of SCG increases and the toughness rises to almost three times the room temperature fracture toughness. The toughness enhancement is due mainly to such processes as crack deflection, crack branching, microcrack zone formation and crack tip blunting rather than any temperature-related increase in intrinsic fracture resistance of the material. In air, the fracture processes are similar to those in vacuum but the toughness increase is delayed by about 100°C and the level of toughening is lower. These differences arise from the formation of a glass phase in air which delays microcrack formation but reduces the resistance to stable crack growth.
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| 9. |
- Hober, Sophia, et al.
(författare)
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Folding of insulin-like growth factor I is thermodynamically controlled by insulin-like growth factor binding protein.
- 1994
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 33:22
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-like growth factor I (IGF-I) is thermodynamically unable to quantitatively form its native disulfides under reversible redox conditions in vitro [Hober et al. (1992) Biochemistry 31, 1749-1756]. These results prompted the question of how IGF-I may overcome this energetic problem in its folding in vivo. Here, we report that an IGF-I precursor, IGF-I-Ea, shows disulfide-exchange folding properties similar to those of mature IGF-I and, thus, is concluded not to overcome the identified folding problem of mature IGF-I. However, correct disulfide bonds are formed very efficiently when insulin-like growth factor binding protein 1 is added in equimolar amounts to IGF-I to the refolding mixture. On the basis of these results, we propose that one important function of at least one of the six homologous insulin-like growth factor binding proteins is to assist in the formation and maintenance of the native disulfides of IGF-I. To our knowledge, this is the first example where the folding of a mammalian protein or peptide in circulation has been demonstrated to be thermodynamically controlled by its binding protein. Speculatively, this could provide a mechanism to regulate the half-life of IGF-I in vivo by altering the interaction with insulin-like growth factor binding proteins.
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| 10. |
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