Mécanismes de la protéolyse dans le lait lors de l'inflammation de la glande mammaire chez la vache laitière : activité des protéases leucocytaires et des protéases bactériennes (cas d'Escherichia coli)

Abstract : Mastitis is a frequently occurring pathological condition that is widely reported in dairy cow, affecting the whole field. The aim of this work is to investigate the endogenous proteolysis that includes mostly proteases of leukocytes and plasmin-plasminogen system in comparison with exogenous bacterial incidence on proteolysis of casein. The result of this study was possible owing to the feasibility of in vivo experimental mastitis using E. coli or endotoxin from E. coli and in vitro inoculation of E. coli strain in raw milk. Proteolysis in E. coli in vivo model enabled proteolysis sequentiality to be achieved. Both somatic cell count and bacteria were involved. Between 3 and 216 h PI; from 15 to 33 h PI the plasmin role was preponderant. During inflammation, many peptide fractions including two of cellular origin were present in the proteose-peptones fraction. The role of E. coli in milk proteolysis, however remains to be elucidated. In vitro study of bacterial proteolysis with E. coli / milk model demonstrated an interaction between bacteria, bacterial proteases and the plasmin-plasminogen system. The second model involving E. coli proteases/casein highlighted a preferential order of caseinolysis. Furthermore, LPS experimental mastitis showed that the gelatinase activity associated with mature blood PMN is more notable than in the immature blood PMN
Complete list of metadatas

Cited literature [144 references]  Display  Hide  Download

https://hal.univ-lorraine.fr/tel-01752478
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 1:49:10 PM
Last modification on : Tuesday, April 10, 2018 - 1:31:26 AM

File

2006_HADDADI_K.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01752478, version 1

Citation

Kahina Haddadi. Mécanismes de la protéolyse dans le lait lors de l'inflammation de la glande mammaire chez la vache laitière : activité des protéases leucocytaires et des protéases bactériennes (cas d'Escherichia coli). Autre. Institut National Polytechnique de Lorraine, 2006. Français. ⟨NNT : 2006INPL021N⟩. ⟨tel-01752478⟩

Share

Metrics

Record views

49

Files downloads

40