Antibiotics | Temperature and Calcium Ions Synergistically Regulate Biofilm Formation Mechanisms in Yersinia

This study reveals the synergistic regulatory mechanisms of temperature and calcium ions on biofilm formation in Yersinia, while elucidating the critical role of the pYV plasmid. Through systematic experimental designs, it provides molecular insights into biofilm formation under varying environmental conditions, offering novel theoretical support for infection control and food safety.

 

Literature Overview
The article 'Temperature Adaptive Biofilm Formation in Yersinia enterocolitica in Response to pYV Plasmid and Calcium' published in Antibiotics summarizes the mechanisms of biofilm formation in Yersinia under different temperatures and calcium concentrations. The study systematically analyzes the combined effects of pYV plasmid, temperature, and calcium ions on bacterial growth, motility, and extracellular polymeric substance (EPS) synthesis, identifying an environmental adaptability biofilm regulatory switch.

Background Knowledge
Yersinia enterocolitica is a significant foodborne pathogen causing gastroenteritis and systemic infections. Biofilm formation enables its persistence in diverse environments (e.g., refrigerated foods, host tissues). Existing research links biofilm formation to bacterial motility, EPS synthesis, and virulence plasmid (pYV). However, the synergistic regulation between temperature and calcium ions remains unclear. This study compares biofilm formation of strains with different plasmid statuses at 26°C and 37°C, integrating motility analysis, qPCR, and EPS quantification to systematically uncover the temperature-dependent regulatory switch. It provides new perspectives for understanding pathogen environmental adaptation and host infection mechanisms, alongside potential targets for biofilm-related infection interventions.

 

 

Research Methods and Experiments
The research team cultured two Yersinia strains (KT0001, pYV-negative; KT0003, pYV-positive) at 26°C and 37°C under varying calcium concentrations (0 mM and 5 mM) to measure biofilm formation. Biofilm quantification employed crystal violet staining, motility analysis used soft agar plates, and EPS quantification included protein, polysaccharide, and extracellular DNA detection. qPCR analyzed flhDC gene expression to assess its correlation with motility and biofilm formation.

Key Conclusions and Perspectives

• At 26°C, the pYV-negative strain KT0001 exhibited strong biofilm formation, primarily dependent on bacterial motility and flagellar expression.
• At 37°C, the pYV-positive strain KT0003 showed significantly enhanced biofilm stability despite growth inhibition, relying on EPS synthesis.
• Calcium ions exhibited temperature-dependent regulation: At 26°C, 5 mM calcium mildly inhibited biofilm formation in pYV-negative strains, while the same concentration at 37°C suppressed EPS synthesis and biofilm formation in KT0003 by up to 50%.
• flhDC gene expression was significantly higher at 26°C than 37°C, particularly under low-calcium conditions, highlighting its critical role in regulating motility and biofilm formation.
• The study identified a novel biofilm regulatory mechanism: Yersinia employs motility-driven biofilm formation at environmental temperatures but switches to pYV plasmid-mediated EPS synthesis for stability at host temperatures.

Research Significance and Prospects
This research provides molecular insights for clinical infection control and food safety, while identifying multiple potential targets within the biofilm regulatory network. Future studies should explore global regulators like Rcs and c-di-GMP in this switching mechanism and evaluate antimicrobial strategies targeting EPS or T3SS in host infection models.

 

 

Conclusion
This study systematically analyzed biofilm formation strategies in Yersinia under varying environmental conditions, uncovering key mechanisms of temperature and calcium ions in pYV plasmid-regulated biofilm dynamics. At 26°C, biofilm formation relies on motility and flagellar expression, whereas at 37°C, pYV-positive strains enhance biofilm stability through EPS synthesis. Calcium ions exhibit dual roles in biofilm and EPS regulation across temperatures, offering new molecular entry points for intervention strategies. These findings deepen understanding of Yersinia's environmental adaptation and host infection mechanisms, providing theoretical foundations for developing anti-biofilm and antimicrobial agents. Future work should validate targeted regulatory strategies using animal models and in vivo imaging technologies.

 

Yunah Oh and Tae-Jong Kim. Temperature Adaptive Biofilm Formation in Yersinia enterocolitica in Response to pYV Plasmid and Calcium. Antibiotics.