Mycobacterium avium subsp. paratuberculosis Proteome Changes Profoundly in Milk

Area of Science:

• Microbiology
• Proteomics
• Food Safety

Background:

• Mycobacterium avium subspecies paratuberculosis (MAP) is found in milk and dairy products.
• The adaptation mechanisms of MAP in these environments are not well understood.

Purpose of the Study:

• To investigate the molecular mechanisms of MAP adaptation in milk using proteomic analysis.
• To identify proteins crucial for MAP survival and potential detection targets.

Main Methods:

• Differential proteomic analysis of MAP cultured in milk (37°C and 4°C) and Middlebrook 7H9 broth.
• Identification and quantification of MAP proteins using mass spectrometry.
• Analysis of protein functional categories and expression patterns.

Main Results:

• 242 out of 2197 identified proteins were significantly upregulated in milk.
• MAP upregulated proteins involved in metabolism (32%), fatty acid metabolism (17%), stress response/immune evasion (19%), transcription/translation (19%), and cell wall synthesis (13%).
• Dut, MmpL4_1, and RecA were uniquely detected in milk, indicating critical roles in adaptation, virulence, and stress response.

Conclusions:

• MAP actively modifies its proteome to cope with the nutritional and environmental challenges of milk.
• Key proteins like Dut, MmpL4_1, and RecA are vital for MAP's survival and virulence in milk.
• 35 stably expressed proteins were identified as potential targets for MAP detection in dairy products.