The present invention is directed generally to eukaryotic cells comprising single-celled organisms that are introduced into the eukaryotic cell through human intervention and which transfer to daughter cells of the eukaryotic cell, and methods of introducing such single-celled organisms into eukaryotic cells. The invention provides single-celled organisms that introduce a phenotype to eukaryotic cells that is maintained in daughter cells. The invention additionally provides eukaryotic cells containing magnetic bacteria. The invention further provides eukaryotic cells engineered with single-celled organisms to allow for multimodal observation of the eukaryotic cells. Each imaging method (or modality) allows the visualization of different aspects of anatomy and physiology, and combining these allows the imager to learn more about the subject being imaged.