Mycobacterium avium subsp. paratuberculosis Proteome Changes Profoundly in Milk
Kristina J H Kleinwort1, Bernhard F Hobmaier1, Ricarda Mayer2
1Chair of Physiology, Department of Veterinary Sciences, LMU Munich, D-82152 Martinsried, Germany.
Abstract:
Mycobacterium avium subspecies paratuberculosis (MAP) are detectable viable in milk and other dairy products. The molecular mechanisms allowing the adaptation of MAP in these products are still poorly understood. To obtain information about respective adaptation of MAP in milk, we differentially analyzed the proteomes of MAP cultivated for 48 h in either milk at 37 °C or 4 °C or Middlebrook 7H9 broth as a control. From a total of 2197 MAP proteins identified, 242 proteins were at least fivefold higher in abundance in milk. MAP responded to the nutritional shortage in milk with upregulation of 32% of proteins with function in metabolism and 17% in fatty acid metabolism/synthesis. Additionally, MAP upregulated clusters of 19% proteins with roles in stress responses and immune evasion, 19% in transcription/translation, and 13% in bacterial cell wall synthesis. Dut, MmpL4_1, and RecA were only detected in MAP incubated in milk, pointing to very important roles of these proteins for MAP coping with a stressful environment. Dut is essential and plays an exclusive role for growth, MmpL4_1 for virulence through secretion of specific lipids, and RecA for SOS response of mycobacteria. Further, 35 candidates with stable expression in all conditions were detected, which could serve as targets for detection. Data are available via ProteomeXchange with identifier PXD027444.
Insights
Mycobacterium avium subspecies paratuberculosis (MAP) adapts to milk by altering protein expression, upregulating metabolism, stress response, and cell wall synthesis proteins. Specific proteins like Dut, MmpL4_1, and RecA are crucial for survival in this environment.
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.
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