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Effect of mastitis on plasminogen activator activity of milk somatic cells

Published online by Cambridge University Press:  01 June 2009

Teffi Zachos ,
Ioannis Politis ,
Ronald C. Gorewit  and
David M. Barbano
Teffi Zachos
Affiliation:
Northeast Dairy Foods Research Center, Departments of Animal Science, Cornell University, Ithaca, NY 14853, USA
Ioannis Politis
Affiliation:
Northeast Dairy Foods Research Center, Departments of Animal Science, Cornell University, Ithaca, NY 14853, USA
Ronald C. Gorewit
Affiliation:
Northeast Dairy Foods Research Center, Departments of Animal Science, Cornell University, Ithaca, NY 14853, USA
David M. Barbano
Affiliation:
Northeast Dairy Foods Research Center, Departments of Food Science, Cornell University, Ithaca, NY 14853, USA
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Summary

This study was conducted to examine the effects of mastitis and stage of lactation on plasminogen activator (PA) activity in milk somatic cells. An assay System, which measures the plasmin-mediated hydrolysis of the chromogenic substrate D-valyl-leucyl-lysine p−nitroanilide, was used to assess PA activity present within milk somatic cells. Milk cell associated PA activity was increased (P < 0·05) by 50% in the presence of fibrin fragments. This suggests that milk somatic cells contain tissue PA which, unlike urokinase PA, is preferentially activated in the presence of fibrin fragments. An increase of the milk somatic cell count from < 5 × 104 to > 106 cells/ml resulted in an 8-fold increase in PA activity per cell. Elevated levels of PA activity were associated with milk somatic cells isolated from mastitic quarters obtained from cows in early (<4 months in lactation) or late lactation (>8 months in lactation). We conclude that PA activity is increased during severe mastitic inflammation. Although the physiological function of this enzyme is as yet unclear, we propose that it may be involved in the conversion of plasminogen to plasmin, contributing to the higher levels of plasmin occurring in milk isolated from mastitic quarters.

Type
Original Articles
Information
Journal of Dairy Research , Volume 59 , Issue 4 , November 1992 , pp. 461 - 467
Copyright
Copyright © Proprietors of Journal of Dairy Research 1992

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References

REFERENCES

De Rham, O. & Andrews, A. T. 1982 Qualitative and quantitative determination of proteolysis in mastitic milks. Journal of Dairy Research 49 587–590CrossRefGoogle ScholarPubMed
Deharveng, G. & Nielsen, S. S. 1991 Partial purification and characterization of native plasminogen activators from bovine milk. Journal of Dairy Science 74 2060–2072Google Scholar
Driessen, F. M. & Van Der Waals, C. B. 1978 Inactivation of native milk proteinase by heat treatmcnt. Netherlands Milk and Dairy Journal 32 245–254Google Scholar
Fox, P. F. 1981 Proteinases in dairy technology. Netherlands Milk and Dairy Journal 35 233–253Google Scholar
Honkanen-Buzalski, T. & Sandholm, M. 1981 Trypsin-inhibitors in mastitic milk and colostrum: correlation between trypsin-inhibitor capacity, bovine serum albumin and somatic cell contents. Journal of Dairy Research 48 213–223CrossRefGoogle ScholarPubMed
Ng-Kwai-Hang, K. F., Hayes, J. F., Moxley, J. E. & Monabdes, H. G. 1984 Variability of test-day milk production and composition and relation of somatic cell counts with yield and compositional changes of bovine milk. Journal of Dairy Science 67 361–366Google Scholar
Politis, I., Lachance, E., Block, E. & Tubner, J. D. 1989 a Plasmin and plasminogen in bovine milk: a relationship with involution. Journal of Dairy Science 72, 900–906CrossRefGoogle ScholarPubMed
Politis, I. & No-Kwai-Hang, K.-F. 1989 b Environmental factors affecting plasmin activity in milk. Journal of Dairy Science 72, 1713–1718CrossRefGoogle ScholarPubMed
Politis, I., Zhao, X., McBride, B. W., Burton, J. H. & Turner, J. D. 1991 Plasminogen activator production by bovine milk macrophages and blood monocytes. American Journal of Veterinary Research 52 1208–1213Google Scholar
Saeman, A. I., Verdi, R. J., Galton, D. M. & Barbano, D. M. 1988 Effect of mastitis on proteolytic activity in bovine milk. Journal of Dairy Science 71 505–512Google Scholar
Saksela, O. 1985 Plasminogen activation and regulation of pericellular proteolysis. Biochimica et Biophysica Acta 823 35–65Google Scholar
Schaar, J. & Funke, H. 1986 Effect of subclinical mastitis on milk plasminogen and plasmin compared with that on sodium, antitrypsin and N-acetyl-β-D-glucosaminidase. Journal of Dairy Research 53 515–528CrossRefGoogle ScholarPubMed
Verdi, R. J. & Barbano, D. M. 1991 Effect of coagulants, somatic cell enzymes, and extracellular bacterial enzymes on plasminogen activation. Journal of Dairy Science 74 772–782Google Scholar