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Published on: February 17, 2014
Protection of mice infected with Plasmodium berghei by Bacillus thuringiensis crystal proteins
Zhaohui Xu1, Baoan Yao, Ming Sun
1College of Life Science and Technology, Huazhong Agricultural University, State Key Laboratory of Agricultural Microbiology, Hubei 430070 Wuhan, China.
Abstract:
Eight Bacillus thuringiensis strains were used to test their activity against Plasmodium berghei. When crystal proteins extracted from strains 007, 017, 020, 021, 030, 032, and 037 were injected into plasmodium-infected mice through the tail vein at a rate of 0.45-1.5 mg per mouse, the lengths of survival for the mice were extended up to 5 days (from 8.5 days to 13.5-15 days). Blood-cell staining demonstrated that normal erythrocytes were lightly stained and regularly shaped while the erythrocytes from plasmodia-infected mice swelled, lost shape and even lysed. This means that the crystal proteins could protect erythrocytes from the plasmodium's attack. Proteins analysis revealed that most of the proteins are homologues of classic crystal proteins, with the exception of the 120-kDa protein of strain 020, a surface-layer protein. This study suggested a novel way to control plasmodial infections and even malaria.
Insights
Crystal proteins from Bacillus thuringiensis extended mouse survival against Plasmodium berghei by up to 5 days. These proteins protected red blood cells from parasite damage, suggesting a new malaria control strategy.
Area of Science:
- Microbiology
- Parasitology
- Biochemistry
Background:
- Plasmodium berghei is a parasite that causes malaria in mice.
- Malaria is a significant global health concern.
- Bacillus thuringiensis produces crystal proteins with insecticidal properties.
Purpose of the Study:
- To investigate the anti-Plasmodium berghei activity of Bacillus thuringiensis crystal proteins.
- To determine if these proteins can protect erythrocytes from parasite-induced damage.
- To explore a novel therapeutic approach for malaria.
Main Methods:
- Eight Bacillus thuringiensis strains were cultured and their crystal proteins extracted.
- Crystal proteins were injected intravenously into Plasmodium berghei-infected mice.
- Erythrocyte morphology and survival rates were analyzed using blood-cell staining and survival time measurements.
- Protein composition was analyzed via electrophoresis.
Main Results:
- Injection of crystal proteins from seven strains (007, 017, 020, 021, 030, 032, 037) extended mouse survival by 5 days (from 8.5 to 13.5-15 days).
- Crystal proteins protected erythrocytes from swelling, shape loss, and lysis caused by Plasmodium berghei.
- Most proteins were homologous to known crystal proteins, with strain 020 containing a unique 120-kDa surface-layer protein.
Conclusions:
- Bacillus thuringiensis crystal proteins exhibit significant anti-Plasmodium berghei activity.
- These proteins offer protection to erythrocytes, mitigating parasite-induced damage.
- This research presents a potential new strategy for controlling plasmodial infections and malaria.
