Flow Cytometry and Electron Microscopy Study of Staphylococcus aureus and Escherichia coli Treated with Mdc-Hly
Xuemei Lu1, Xiaobao Jin1, Jiayong Zhu1
11School of Basic Courses,Guangzhou Higher Education Mega Center,Guangdong Pharmaceutical University,280 Wai Huan Dong Road,Guangzhou,Guangdong 510006,People's Republic of China.
Abstract:
In our previous study, a novel hybrid protein combining human lysozyme (Hly) with Musca domestica cecropin (Mdc) was successfully constructed. The broad antibacterial activity against various foodborne pathogens of Mdc-hly suggests its scope as a food preservative. The aim of the present study was to investigate the antibacterial mechanism of the recombinant Mdc-hly. The damage induced by Mdc-hly on Staphylococcus aureus and Escherichia coli was investigated using flow cytometry (FC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of FC showed that Mdc-hly causes bacterial membrane permeabilization. SEM and TEM studies revealed that Mdc-hly is capable of damaging both the membrane and the wall of bacteria, resulting in efflux of essential cytoplasmic contents. Both FC and EM revealed that the effects of Mdc-hly were greater than its parental peptides. Understanding the antibacterial mechanism of Mdc-hly is of a great interest in further utilization of its use in treatment of food and in clinical environments.
Insights
The novel hybrid protein Mdc-hly damages bacterial membranes and walls, offering a potent antibacterial effect against foodborne pathogens. This mechanism enhances its potential as a food preservative and for clinical applications.
Area of Science:
- Biochemistry
- Microbiology
- Food Science
Background:
- A novel hybrid protein, Mdc-hly, was previously constructed by combining human lysozyme (Hly) and Musca domestica cecropin (Mdc).
- Mdc-hly exhibits broad-spectrum antibacterial activity against foodborne pathogens, indicating its potential as a food preservative.
Purpose of the Study:
- To elucidate the antibacterial mechanism of the recombinant Mdc-hly protein.
- To investigate the specific damage induced by Mdc-hly on bacterial cells.
Main Methods:
- Utilized flow cytometry (FC) to assess bacterial membrane permeabilization.
- Employed scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to visualize structural damage to bacterial cells.
- Compared the effects of Mdc-hly with its parental peptides, Hly and Mdc.
Main Results:
- Flow cytometry confirmed that Mdc-hly induces significant bacterial membrane permeabilization.
- Electron microscopy revealed that Mdc-hly damages both the bacterial membrane and cell wall.
- Observed efflux of essential cytoplasmic contents from treated bacterial cells.
- Mdc-hly demonstrated greater efficacy in damaging bacteria compared to its individual parental peptides.
Conclusions:
- Mdc-hly exerts its antibacterial effect by compromising bacterial membrane and wall integrity, leading to cell lysis.
- The enhanced antibacterial activity of Mdc-hly compared to its parent peptides highlights its potential for food preservation.
- Further research into the antibacterial mechanism of Mdc-hly is crucial for its application in food safety and clinical settings.
