RESUMEN
OBJECTIVE: To increase the resistance of ingested bacteria to multiple environmental stresses, the role of transglutaminase in Lactococcus lactis and possible mechanisms of action were explored. RESULTS: L. lactis grown with transglutaminase exhibited significantly higher resistance to bile salts, stimulated gastric juice, antibiotics, NaCl, and cold stress compared to the control (cultured without transglutaminase), with no negative influence on cell growth. Transmission electron microscopy revealed that the cell walls of L. lactis cultured with 9 U transglutaminase/ml were approx. 1.9-times thicker than the control. Further analysis demonstrated that the multi-resistant phenotype was strain-specific; that is, it occurred in bacteria with the presence of glutamine and lysine in the peptidoglycan. CONCLUSION: Supplementation of culture media with transglutaminase is an effective, simple, and inexpensive strategy to protect specific ingested bacteria against multiple environmental challenges.
Asunto(s)
Pared Celular/química , Glutamina/análisis , Lactococcus lactis/efectos de los fármacos , Limosilactobacillus fermentum/efectos de los fármacos , Lisina/análisis , Estrés Fisiológico , Transglutaminasas/metabolismo , Antibacterianos/metabolismo , Pared Celular/ultraestructura , Frío , Limosilactobacillus fermentum/fisiología , Limosilactobacillus fermentum/ultraestructura , Lactococcus lactis/fisiología , Lactococcus lactis/ultraestructura , Microscopía Electrónica de Transmisión , Peptidoglicano/análisisRESUMEN
Fe(3)O(4) modified by chitosan (CTS) and Staphylococcus aureus enterotoxin A (SEA) antiserum immunomagnetic beads (Fe(3)O(4)-CTS-SEA-IB) that targeted enrich SEA were prepared in aqueous solution and using CTS and SEA antiserum as surface modification stabilizer. Recognition experiments of the prepared Fe(3)O(4)-CTS-SEA-IB on SEA were conducted to determine adsorption capacity and recognition specificity. The results showed that the SEA antiserum were prepared and successfully conjugated onto Fe(3)O(4)-modificated CTS magnetic beads. The Fe(3)O(4)-CTS-SEA immunomagnetic beads displayed a high adsorption capacity and recognition specificity for SEA, and the adsorption quantity could reach 6.48 × 10(-3) µmol/g. The specificity evaluation results showed that the Fe(3)O(4)-CTS-SEA immunomagnetic beads had high enrichment and affinity property for SEA compared to SEB (Staphylococcus aureus enterotoxin B) and SPA (Staphylococcus aureus protein A).