Related Experiment Videos
[Characterization of hemolytic activity of Proteus penneri]
A Rózalski1, B Bartodziejska, M Wykrota
1Instytut Mikrobiologii i Immunologii Uniwersytetu Lódzkiego.
Abstract:
Bacteria belonging to the genus Proteus synthesise two kinds of hemolysins HpmA and HlyA which represent "RTX proteins". In previous papers we described the production of an extracellular HlyA hemolysin by some P. penneri strains. Now we are reporting on the synthesis by P. penneri, typical for P. mirabilis HpmA hemolysin. There were identified two P. penneri strains 5 and 37 in which both hpmA and hlyA regions are present. In two other strains P. penneri 13 and 44 only hlyA region was found, whereas in strain P. penneri 42 operon hpmA was identified. The production of HpmA hemolysin was revealed in the cases of P. penneri 5, 42 and P. mirabilis 03 and 1959. The dynamics of HlyA hemolysin synthesis by P. penneri 44 was also investigated and its highest activity was observed during logarithmic phase of growth of bacterial culture. HlyA hemolysin was isolated from culture filtrate by precipitation with polyethylene glycol 4000. The invasiveness of HpmA+ and/or HlyA+ P. penneri strains was also checked by use of mouse L929 fibroblasts. Both kinds of strains were able to penetrate tested cells. The invasion of L929 fibroblasts by strains producing HlyA hemolysin is accompanied by cytotoxic effect.
Insights
Proteus penneri bacteria can produce HpmA and HlyA hemolysins, RTX proteins that enable bacterial invasion and cytotoxicity. This study identifies strains synthesizing these hemolysins and examines their invasive capabilities.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
Context:
- Proteus bacteria are known to produce RTX hemolysins, HpmA and HlyA.
- Previous research focused on HlyA hemolysin production by P. penneri.
- This study investigates HpmA hemolysin synthesis in P. penneri.
Purpose:
- To identify P. penneri strains synthesizing HpmA and/or HlyA hemolysins.
- To characterize the production dynamics of HlyA hemolysin.
- To assess the invasiveness of hemolysin-producing P. penneri strains.
Summary:
- Two P. penneri strains (5 and 37) possess both hpmA and hlyA regions.
- P. penneri strains 5, 42, and P. mirabilis strains 03 and 1959 produce HpmA hemolysin.
- HlyA hemolysin production by P. penneri 44 peaked during the logarithmic growth phase.
- HlyA hemolysin was isolated using polyethylene glycol 4000 precipitation.
- Both HpmA+ and HlyA+ P. penneri strains demonstrated invasiveness against L929 fibroblasts.
- HlyA hemolysin-producing strains exhibited cytotoxicity during fibroblast invasion.
Impact:
- Identifies specific Proteus strains capable of producing key virulence factors.
- Provides insights into the regulation of hemolysin synthesis.
- Demonstrates the role of HpmA and HlyA hemolysins in bacterial invasion and cytotoxicity.
- Contributes to understanding Proteus virulence mechanisms.