Related Experiment Videos
Methods for purification of Rickettsia prowazekii separated from the host tissue: a step-by-step comparison
L P Aniskovich1, M E Eremeeva, N M Balaeva
1N. F. Gamaleya Research Institute of Epidemiology and Microbiology, U.S.S.R. Academy of Medical Sciences, Moscow.
Abstract:
Two methods for purification of Rickettsia prowazekii strains E, E Vir, and Breinl grown in chick embryo yolk sacs are described. These methods combine either differential centrifugation or sucrose mix, centrifugation through sucrose cushion, 10 mmol/l MgCl2 treatment, filtration through a glass filter AP-20 and 2 cycles of verografin discontinuous density gradient centrifugation. The purification procedure including sucrose mix allowed to recover about 38-42% biologically active rickettsiae, a yield which was by 10% higher than that obtained by the method beginning at differential centrifugation. The rickettsiae free of host cell components preserved their infectious activity. The obtained biomass was suitable for immunological and biological characterization of Rickettsia prowazekii and for isolation of its total DNA.
Insights
Two methods were developed to purify Rickettsia prowazekii bacteria from infected chick embryos. The sucrose mix method yielded more biologically active bacteria, suitable for further research.
Area of Science:
- Microbiology
- Infectious Diseases
- Biotechnology
Background:
- Rickettsia prowazekii is an obligate intracellular bacterium causing epidemic typhus.
- Efficient purification methods are crucial for studying R. prowazekii's biology and developing diagnostics or vaccines.
- Existing purification techniques may impact bacterial viability and yield.
Purpose of the Study:
- To describe and compare two novel purification methods for Rickettsia prowazekii strains.
- To assess the yield and biological activity of purified R. prowazekii using the developed methods.
- To determine the suitability of the purified bacteria for downstream applications like immunological characterization and DNA isolation.
Main Methods:
- Two purification strategies were employed, involving differential centrifugation or a sucrose mix.
- Key steps included sucrose cushion centrifugation, MgCl2 treatment, filtration, and verografin discontinuous density gradient centrifugation.
- Purification was performed on R. prowazekii strains (E, E Vir, Breinl) grown in chick embryo yolk sacs.
Main Results:
- The purification method incorporating a sucrose mix achieved a higher yield of biologically active rickettsiae (38-42%).
- This yield was approximately 10% greater than that obtained using the differential centrifugation-based method.
- Purified R. prowazekii remained infectious and free of host cell contaminants.
Conclusions:
- The developed purification methods effectively isolate viable Rickettsia prowazekii.
- The sucrose mix-based protocol offers a superior yield of infectious rickettsiae.
- The purified bacterial biomass is suitable for immunological, biological, and genetic analyses of R. prowazekii.