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- Choularton, T. W., et al.
(author)
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The Great Dun Fell Cloud Experiment 1993 : An overview
- 1997
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In: Atmospheric Environment. - 1352-2310. ; 31:16, s. 2393-2405
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Journal article (peer-reviewed)abstract
- The 1993 Ground-based Cloud Experiment on Great Dun Fell used a wide range of measurements of trace gases, aerosol particles and cloud droplets at five sites to study their sources and sinks especially those in cloud. These measurements have been interpreted using a variety of models. The conclusions add to our knowledge of air pollution, acidification of the atmosphere and the ground, eutrophication and climate change. The experiment is designed to use the hill cap cloud as a flow-through reactor, and was conducted in varying levels of pollution typical of much of the rural temperate continental northern hemisphere in spring-time.
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| 3. |
- Biver, N, et al.
(author)
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Long-term evolution of the outgassing of comet Hale-Bopp from radio observations
- 1997
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In: EARTH MOON AND PLANETS. - : KLUWER ACADEMIC PUBL. - 0167-9295. ; 78:1-3, s. 5-11
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Journal article (peer-reviewed)abstract
- C/1995 O1 (Hale-Bopp) has been observed on a regular basis since August 1995 at millimetre and submillimetre wavelengths using IRAM, JCMT, CSO and SEST radio telescopes. The production rates of eight molecular species (CO, HCN, CH3OH, H2CO, H2S, CS, CH3CN
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| 6. |
- Kleywegt, GJ, et al.
(author)
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The crystal structure of the catalytic core domain of endoglucanase I from Trichoderma reesei at 3.6 angstrom resolution, and a comparison with related enzymes
- 1997
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In: JOURNAL OF MOLECULAR BIOLOGY. - 0022-2836. ; 272:3, s. 383-397
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Journal article (peer-reviewed)abstract
- Cellulose is the most abundant polymer in the biosphere. Although generally resistant to degradation, it may be hydrolysed by cellulolytic organisms that have evolved a variety of structurally distinct enzymes, cellobiohydrolases and endoglucanases, for this purpose. Endoglucanase I (EG I) is the major endoglucanase produced by the cellulolytic fungus Trichoderma reesei, accounting for 5 to 10% of the total amount of cellulases produced by this organism. Together with EG I from Humicola insolens and T. reesei cellobiohydrolase I (CBH I), the enzyme is classified into family 7 of the glycosyl hydrolases, and it catalyses hydrolysis with a net retention of the anomeric configuration.The structure of the catalytic core domain (residues 1 to 371) of EG I from T. reesei has been determined at 3.6 A resolution by the molecular replacement method using the structures of T. reesei CBH I and H. insolens EG I as search models. By employing the 2-fold non-crystallographic symmetry (NCS), the structure was refined successfully, despite the limited resolution. The final model has an R-factor of 0.201 (Rfree 0.258).The structure of EG I reveals an extended, open substrate-binding cleft, rather than a tunnel as found in the homologous cellobiohydrolase CBH I. This confirms the earlier proposal that the tunnel-forming loops in CBH I have been deleted in EG I, which has resulted in an open active site in EG I, enabling it to function as an endoglucanase. Comparison of the structure of EG I with several related enzymes reveals structural similarities, and differences that relate to their biological function in degrading particular substrates. A possible structural explanation of the drastically different pH profiles of T. reesei and H. insolens EG I is proposed.
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| 7. |
- Nordman, H, et al.
(author)
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Mucus glycoproteins from pig gastric mucosa: identification ofdifferent mucin populations from the surface epithelium.
- 1997
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In: The Biochemical journal. - 0264-6021. ; 326 ( Pt 3), s. 903-10
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Journal article (peer-reviewed)abstract
- Pig gastric mucins were isolated from the surface epithelium of the cardiac region, corpus and antrum using density-gradient centrifugation after extraction in 6 M guanidinium chloride. In CsCl/0.5 M guanidinium chloride, mucins solubilized from the cardiac region appeared as a broad unimodal band at 1.52 g/ml whereas those from the corpus and antrum occurred as high- and low-density populations at 1.50 and 1.45 g/ml respectively. High-iron diamine reacted more strongly with the cardiac mucins and the high-density populations from corpus and antrum than with the two low-density ones. In keeping with this, approx. 60% of the oligosaccharides from the former mucins and 20% from the latter contained sulphate. All surface epithelial cells of the cardiac region stained with high-iron diamine, whereas in the corpus only the epithelium in the bottom of the pits reacted, suggesting that the high-density population from this region originates from these cells. Mucins from all regions were composed of subunits, each containing highly glycosylated domains. The mucins from the cardiac region were larger than those from the corpus and antrum, and reduced subunits as well as high-molecular-mass glycopeptides from the cardiac mucins were larger than the corresponding fragments from the other regions. Ion-exchange HPLC showed that reduced subunits from the cardiac mucins and the high-density populations from the corpus and antrum were more 'acidic' than reduced subunits from the two low-density ones. All mucins contained a 'neutral'fraction, in particular those from the antrum. Pig gastric mucus thus contains a number of distinctly different mucin populations varying in buoyant density, size, 'acidity', glycosylation, sulphation and tissue origin.
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