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Activation of Plasmin in Mastitic Milk
Plasmin aktivering i mastitmjölk
Acta Veterinaria Scandinavica volume 29, pages 485–491 (1988)
Abstract
Milk and whey samples from healthy and inflamed udder quarters of 10 Ayrshire cows were analyzed for proteolytic activity using radial caseolysis procedures, a fluorogenic coumaryl peptide substrate, and casein agarose zymography. Free lysosomal enzyme activity (N–acetyl–beta–D–glucosaminidase) was used as the criterion for inflammation. All mastitic milk samples had proteolytic activity, tentatively identified as plasmin (comigration at Mr 83 000 and characteristic fragmentation). The plasmin activities in mastitic milk were on average 2.9 μg/ml (range 0.5–12.5) as measured by radial caseolysis. Milk or whey specimens from healthy quarters were all negative except 1 in which an activity of 0.1 μg/ml was found in both specimens. The caseolytic activities were totally inhibited by 50 KITJ/ml of aprotinin, a serine proteinase inhibitor from bovine lung. No free plasminogen activator (PA) activity was found in any of the samples. Howewer, according to zymographic analyses PA molecules corresponding to urokinase were found in healthy and especially in mastitic specimens. Analysis of plasmin may provide an alternative means of screening for mastitic milk samples.
Sammanfattning
Mjölk och mjölkserum prov från friska och inflammerade juverfjärdedelar från tio aushire kor analyserades beträffande proteolytisk aktivitet genom att använda en radial kaseinolysmetod, ett fluorgeniskt kumaryl peptid substrat och kasein agar zymatografi. Fri lysosomal aktivitet (N-acetyl-β-D-glucosaminidase) användes som mått på inflammation. Alla mastitmjölk prov visade proteolytisk aktivitet, preliminärt identifierad som plasmin (komigration vid Mr 83000 och karakteristisk fragmentering. Plasmin aktiviteten i mastitmjölk var i medeltal 2,9 µg/ml (range 0,5–12,5) med radial kaseinolys. Aktiviteten i mjölk och mjölkserum från friska juverfjärdedelar var negativ i alla utom ett prov, i vilken aktiviteten var 0,1 µg/ml både i mjölk och mjölkserum. Den kaseinolytiska aktiviteten inhiberades totalt av 50 KIU/ml aprotinin, en serin proteinas inhibitor från bovin lunga. Fri plasminogen aktivator (PA) aktivitet mättes inte i något av proven. Enligt zymografíska analyser hittades dock PA molekyler som motsvarar urokinas både i friska och särskilt i mastit mjölkprov. Analys av plasmin aktivitet kan vara en alternativ metod för undersökning av mastit mjölkprov.
References
Andrews AT: Breakdown of caseins by proteinases in bovine milks with high somatic cell counts arising from mastitis or infusion with bacterial endotoxin. J. Dairy Res. 1983, 50, 57–66.
Barlow GH, Francis CW, Marder VT: On the conversion of high molecular weight urokinase to the low molecular weight form by plas–min. Thromb. Res. 1981, 23, 541–547.
Blasi F: Surface receptors for urokinase plasminogen activator. Fibrinolysis 1988, in press.
Danø K, Andreasen PA, Gwøndahl–Hansen J, Kri–stensen P, Nielsen LS, Skriver L: Plasminogen activators, tissue degradation and cancer. Adv. Cancer Res. 1985, 44, 139–266.
Eigel WN, Hofmann CJ, Chibber BAK, Tomich JM, Keenan TW, Mertz ET: Plasmin–medi–ated proteolysis of casein in bovine milk. Proc. Natl. Acad. Sci. USA 1979, 76, 2244–2248.
Granelli-Piperno A, Reich E: A study of proteases and protease–inhibitor complexes in biological fluids. J. exp. med. 1978, 146, 223–234.
Kaartinen L, Sandholm M: Regulation of plas-min activation in mastitic milk–Correlation with inflammatory markers and growth of Streptococcus agalactiae. J. Vet. Med. B. 1987, 34, 42–50.
Kitchen BJ: Review of the progress of dairy science: Bovine mastitis: compositional changes and related diagnostic tests. J. Dairy Res. 1981, 48, 167–188.
Korycka-Dahl M, Ribadeau Dumas B, Chene N, Martal J: Plasmin activity in milk. J. Dairy Sci. 1983, 66, 704–711.
Laemmli UK: Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature (London) 1970, 227, 680–685.
Manila T, Syväjärvi J, Sandholm M: Milk antitrypsin, NAGase, plasmin and bacterial replication rate in whey–effect of lactation stage, parity and daily milk yield. J. Vet. Med. B. 1986, 33, 462–470.
Richardson BC, Pearce KN: The determination of plasmin in dairy products. New Zealand J. Dairy Sci. Technol. 1981, 16, 209–220.
Saksela O: Radial caseinolysis in agarose: a simple method for detection of plasminogen activator in the presence of inhibitory substances and serum. Anal. Biochem. 1981, 111, 276–282.
Salonen EM, Tervo T, Törmä E, Tarkkanen A, Vaheri A: Plasmin in tear fluid of patients with corneal ulcers: basis for new therapy. Acta Ophthalmol. 1987, 65, 3–12.
Sprengers ED, Kluft C: Plasminogen activator inhibitors. Blood 1987, 69, 381–387.
Travis J, Salvesen GS: Human plasma proteinase inhibitors. Ann. Rev. Biochem. 1983, 52, 655–709.
Acknowledgments
We thank Dr. Ross W. Stephens for critical reading of the manuscript, Ms. Taija Kyöstiö–Renvall for expert technical assistance and the Sigrid Jusélius Foundation, Helsinki and the Medical Research Council of the Academy of Finland for financial support.
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Kaartinen, L., Salonen, E., Vaheri, A. et al. Activation of Plasmin in Mastitic Milk. Acta Vet Scand 29, 485–491 (1988). https://doi.org/10.1186/BF03548646
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DOI: https://doi.org/10.1186/BF03548646