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Author |
Rodier, F. |
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Title |
[Spectral properties of porcine plasminogen: study of the acidic transition (author's transl)] |
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Journal Article |
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Year |
1976 |
Publication |
European journal of biochemistry / FEBS |
Abbreviated Journal |
Eur J Biochem |
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Volume |
63 |
Issue |
2 |
Pages |
553-562 |
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Keywords  |
Animals; Binding Sites; Guanidines; Hydrogen-Ion Concentration; *Plasminogen; Protein Binding; Protein Conformation; Spectrometry, Fluorescence; Spectrophotometry; Spectrophotometry, Ultraviolet; Swine; Temperature |
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Abstract |
The acidic transition of porcine plasminogen, prepared by affinity chromatography, was studied by non-destructive methods. These methods are based on the analysis of the behaviour of the tryptophyls under various conditions. The perturbation of the absorption and emission spectra by pH or temperature and the dynamic quenching of the intrinsic fluorescence are used to obtain information on structural changes which affect the environment of these residues. It is shown that by decreasing pH the fluorescence emission spectra are shifted toward the long wavelengths, with a broadening of the fluorescence band. The same effect can be obtained at constant pH by heating the protein solution. In order to analyze these phenomena, it is assumed that the fluorescence intensities at 355 nm and 328 nm reflect the proportion of the tryptophans which are exposed to the solvent, and buried, respectively. The plot of the ratio of the fluorescence intensities at these wavelengths versus pH or temperature leads to a titration curve showing an unmasking of tryptophans. The proportion of exposed tryptophans is measured by the dynamic fluorescence quenching technique and the data analyzed according to Lehrer. The plot of the fraction of exposed tryptophyls versus pH also shows the unmasking of these chromophores. Thermal perturbation of a solution of plaminogen at neutral pH induces a difference absorption spectrum whose amplitudes at the maxima are proportional to the number of exposed aromatic residues. The comparison with a solution of fully denatured plasminogen in 6 M guanidium chloride, where all the tryptophyls are exposed, shows that the percentage of exposure is equal to 59%. This number is significantly higher than the percentage found by the fluorescence quenching technique (20%), indicating that some tryptophyls are located in crevices, exposed to the solvent but not to the iodide. At acidic pH the absorption difference spectra induced by thermal perturbation are not classical, since they show an inversion and a new band between 300 nm and 305 nm. This band is mentioned in the literature as a minor band of tryptophan which appears when this chromophore is located in an asymmetric environment. On plotting the maximum amplitude of these spectra obtained at acidic pH versus temperature, we obtain a curve indicating that two types of antagonistic interactions are involved in the perturbation of the chromophores spectra. The spectrophotometric titration of plasminogen gives classical absorption difference spectra. By plotting the maximum amplitude at 292 nm versus pH, we obtain a titration curve with an apparent pK of 2.9 units. This pK is acidic which respect to the pK value of a normal carboxyl. This low value can be due to a positively charged group in the neighbourhood of a carboxyl, which interacts with one or more chromophores. When the carboxyl becomes protonated, this positively charged group is free and available to perturb the environment of some chromophores... |
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Language |
French |
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Original Title |
Proprietes spectrales du plasminogene porcin. Etude de la transition acide |
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ISSN |
0014-2956 |
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Notes |
PMID:4326 |
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Call Number |
Admin @ knut @ |
Serial |
22 |
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Author |
Lutta, A.S. |
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Title |
[Distribution and biology of Heptatoma pellucens in the Karelian ASSR (fam. Tabanidae)] |
Type |
Journal Article |
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Year |
1976 |
Publication |
Parazitologiia |
Abbreviated Journal |
Parazitologiia |
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Volume |
10 |
Issue |
1 |
Pages |
53-55 |
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Keywords |
Animals; Biology; *Diptera; Ecology; Female; Horses/parasitology; Larva; Russia |
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Abstract |
The analysis is given of the peculiarities of the distribution of the widely spread forest subspecies Heptatoma pellucens pellucens Fabr. in the northern part of its distribution area in Karelia. Some data on the biology of the larva of this subspecies are presented. |
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Russian |
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Original Title |
K rasprostraneniiu i biologii Heptatoma pellucens v Karel'skoi ASSR (sem. Tabanidae) |
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0031-1847 |
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Notes |
PMID:133320 |
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Call Number |
Equine Behaviour @ team @ |
Serial |
2701 |
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Author |
Grafner, G.; Zimmermann, H.; Karge, E.; Munch, J.; Ribbeck, R.; Hiepe, T. |
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Title |
[Incidence and damages inflicted by simuliid flies in the GDR district of Schwerin] |
Type |
Journal Article |
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Year |
1976 |
Publication |
Angewandte Parasitologie |
Abbreviated Journal |
Angew Parasitol |
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Volume |
17 |
Issue |
1 |
Pages |
2-6 |
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Keywords |
Animals; Cattle; Cattle Diseases/*parasitology; Climate; *Diptera/growth & development; Ecology; Ectoparasitic Infestations/*veterinary; Germany, East; Horse Diseases/*parasitology; Horses; Swine; Swine Diseases/*parasitology |
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Abstract |
Systematic faunal studies in the district Schwerin showed at the present time there are 3 more or less damage-biotopes existing in the districts of Perleberg, Ludwigslust and Parchim; 5 river sources can be considered as potential sources, 5 are temporary and 2 are ephemeral whilst in 3 further areas environmental influences such as effluent impairs the flow of the river and the developmental stages of Simuliidae were not observed.--The following species were found: Boophthora erythrocephala, Wilhelmia salopiensis, Wilhelmia equina, Odagmia ornata, Eusimulium aureum and Eusimulium lundstroemi.--The damage statistics covering the period 1966--1971 showed in the district of Schwerin, due to Simuliid attacks, 38 cattle died, 170 were seriously ill; in 1967 5 horses were seriously ill; in 1971, 3 pigs died and 27 were seriously ill.--The symptoms were manifested by pathological petechiae, scabs and oedema, also by insufficiency of the heart and circulatory system, diminished performance and growth disturbance. In severe cases heart and circulation failure occurred, paresis, coma and death followed.--The real economic significance of the Simuliid attacks rest with its strong and prolonged distrubance in young animals, as well as in pronounced irreparable diminished performance in diseased dairy cattle. |
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German |
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Original Title |
Vorkommen und Schadwirkung von Kriebelmucken im DDR-Bezirk Schwerin |
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Edition |
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ISSN |
0003-3162 |
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Notes |
PMID:1267220 |
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Call Number |
Equine Behaviour @ team @ |
Serial |
2699 |
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