#10 - Engineering bacterial membrane mimicking minimal cells

Harsha Bajaj (CSIR National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram)

Monday, 30 Nov 21:15 - 22:00 CET

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Abstract

Title: Engineering bacterial membrane mimicking minimal cells

Author(s): Karthika S. Nair, Neethu B. Raj, Gayathri Mohanan, and Harsha Bajaj^a

Affiliations: ^aCSIR National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram

Abstract: Engineering of minimal cells mimicking the native membrane opens up various platforms for research in membrane and bottom-up biology [1]. In this work, giant unilamellar vesicles (GUV) mimicking membrane of Gram- negative and Gram-positive bacterium are engineered under physiological salt condition. We have used an E. coli lipid extract for Gram- negative(GN) model and a ternary lipid mixture mimicking membrane of Staphylococcus aureus for Gram-positive (GP) model. Importantly, we incorporate LPS in Gram-negative (GN) vesicles (OMM model) by inverse-phase precursor film assembly to mimic Gram-negative outer-membrane and confirm at single-vesicle level using fluorescence detection system. Controlled size of the vesicles is realised by formation via gel-assisted technology. The applicability of the models is confirmed by quantifying the transport of antibiotics across the membranes which demonstrate orders of magnitude difference in transport rate among the three different models. We show that the vesicle models can be successfully used as a scaffold to study antimicrobial activity of peptides like dermcidin and melittin. Functionality of the vesicle models is shown by reconstitution of model membrane protein pore. The models engineered here are not only crucial for understanding of membrane transport mechanisms , but also form a building block towards construction of a protocell [2].

References

[1] Rideau, Emeline, Rumiana Dimova, Petra Schwille, Frederik R. Wurm, and Katharina Landfester. “Liposomes and Polymersomes: A Comparative Review towards Cell Mimicking.” Chemical Society Reviews 47, no. 23 (2018): 8572–8610. https://doi.org/10.1039/C8CS00162F.

[2] Mohanan, Gayathri, Karthika S. Nair, K. Madhavan Nampoothiri, and Harsha Bajaj. “Engineering Bio-Mimicking Functional Vesicles with Multiple Compartments for Quantifying Molecular Transport.” Chemical Science 11, no. 18 (2020): 4669–79. https://doi.org/10.1039/D0SC00084A.