from the would-they-swim-backwards-in-the-southern-hemisphere? dept.
Arthur T Knackerbracket has found the following story:
Magnetic bacteria might soon be used for the production of novel biomaterials. A team of microbiologists at the University of Bayreuth led by Prof. Dr. Dirk Schüler developed a modular system for the genetic reprogramming of bacteria, thereby turning the organisms into cell factories for multifunctional magnetic nanoparticles that combine various useful functions and properties. Because of their exceptional magnetic properties and good biocompatibility, these nanoparticles might be a promising new material in the biomedical and biotechnological field. In the journal Small the scientists presented their findings.
Magnetic bacteria of the species Magnetospirillum gryphiswaldense align their swimming behaviour along the Earth's magnetic field. Within the cells, magnetic nanoparticles, the magnetosomes, are arranged in a chain-like manner, thereby forming an intracellular compass needle. Each magnetosome consists of a magnetic iron oxide core surrounded by a membrane. In addition to lipids, this membrane also contains a variety of different proteins. The microbiologists of the University of Bayreuth have now succeeded in the coupling of biochemically active functional groups, which originate from various foreign organisms, to these proteins. The method used here starts at the stage of the genes that are responsible for the biosynthesis of the membrane proteins. These bacterial genes are fused to foreign genes from other organisms that control the production of the respective functional proteins. As soon as the genes are re-integrated into the genome, the reprogrammed bacteria produce magnetosomes that display these foreign proteins permanently installed on the particle surface.
In the study, four different functional groups (i.e. foreign proteins) were coupled to the membrane proteins. These include the enzyme glucose oxidase from a mould fungus, which is already used biotechnologically, for example as a "sugar sensor" in diabetes diseases. In addition, a green fluorescent protein from a jellyfish and a dye-producing enzyme from the bacterium Escherichia coli, whose activity can be easily measured, were installed on the surface of the magnetosomes. The fourth functional group is an antibody fragment from a lama (Alpaca) that was used as a versatile connector. Thus, all these properties including the superb magnetization of the magnetosomes are genetically encoded in the bacteria.
"Using this genetic strategy, we reprogrammed the bacteria to produce magnetosomes that glow green when irradiated with UV light and at the same time display novel biocatalytic functions. Various biochemical functions can be precisely installed on their surfaces. Thereby, magnetosomes from living bacteria are transformed into multifunctional nanoparticles with fascinating functions and properties. Moreover, the particles remain fully functional when they are isolated from the bacteria—which can be easily performed by taking advantage of their inherent magnetic properties," says Professor Dirk Schüler, who led the research team.
Journal Reference: Frank Mickoleit et al. A Versatile Toolkit for Controllable and Highly Selective Multifunctionalization of Bacterial Magnetic Nanoparticles, Small (2020). DOI: 10.1002/smll.201906922
