Proteolytic Activities Expressed by Gastrointestinal Pathogens , and in Different Growth Phases.

AIMS

Bacterial proteases are implicated in protein quality control, biofilm formation or might have a direct function in pathogenesis by processing virulence factors or cleaving host factors. In recent years, knowledge of proteases expressed by Gram-negative pathogens remarkably increased. However, investigation of proteases from Gram-positive bacteria is rather rare, but required for the analysis of pathogenesis-relevant proteases. In this study, we extracted and detected proteases from the gastrointestinal pathogens , , and in different growth phases.

METHODOLOGY

Bacteria were grown to logarithmic or stationary phases, harvested and extracted by sonication and French press. For the detection of active proteases, zymography analyses were performed using casein and gelatin as substrates to monitor caseinolytic and gelatinolytic activities.

RESULTS

We observed different active proteases with different intensities in bacteria grown to logarithmic or stationary phases. Strong activities as gelatinases were detected in and distinct caseinolytic proteases exhibiting molecular weights of > 170 kDa, 70 kDa and 45 kDa were shown in and , respectively. Interestingly, detected proteases were differentially regulated in bacteria grown to logarithmic or stationary phases.

CONCLUSION

In summary, the data clearly indicated proteases that are differentially regulated in the Gram-positive pathogens , , and , which might contribute to bacterial pathogenesis.