Co-Authors:
Silanikove, N., Ruminant Physiology, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Shapiro, F., Ruminant Physiology, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Leitner, G., National Mastitis Reference Center, Kimron Veterinary Institute, Bet Dagan, 50250, Israel
Abstract:
The aims of this study were to test the hypothesis that the substrates of xanthine oxidase (XO), xanthine and hypoxanthine, are consumed while the milk is stored in the gland between milkings, and to explore how XO activity responds to bacteria commonly associated with subclinical infections in the mammary gland. Freshly secreted milk was obtained following complete evacuation of the gland and induction of milk ejection with oxytocin. In bacteria-free fresh milk xanthine and hypoxanthine were converted to uric acid within 30 min (T1/2 ∼ 10 min), which in turn provides electrons for formation of hydrogen peroxide and endows the alveolar lumen with passive protection against invading bacteria. On the other hand, the longer residence time of milk in the cistern compartment was not associated with oxidative stress as a result of XO idleness caused by exhaustion of its physiological fuels. The specific response of XO to bacteria species and the resulting bacteria-dependent nitrosative stress further demonstrates that it is part of the gland immune system. © 2007 Elsevier Inc. All rights reserved.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
