The present invention is directed generally to eukaryotic host cells comprising artificial endosymbionts and methods of introducing artificial endosymbionts into eukaryotic host cells. The invention provides artificial endosymbionts that introduce a phenotype to host cells that is maintained in daughter cells. The invention additionally provides eukaryotic host cells containing magnetotactic bacteria.

Methods of transferring large sequence fragments between chromosomes and generating chromosomal rearrangements using double strand break repair pathways and homology directed repair. Further relates to chromosomes produced by these methods, and cells and transgenic animals comprising these chromosomes.

The present invention is directed generally to eukaryotic host cells comprising artificial endosymbionts and methods of introducing artificial endosymbionts into eukaryotic host cells. The invention provides artificial endosymbionts that introduce a phenotype to host cells that is maintained in daughter cells. The invention additionally provides eukaryotic host cells containing magnetotactic bacteria.

The present invention relates to a gallinaceous bird embryo into which human neuroblastoma cells have been grafted at the level of the neural crests. The invention also relates to a process for preparing such a gallinaceous bird embryo, and to a process for screening for therapeutic molecules intended for the treatment of a neuroblastoma tumor based on the use of this gallinaceous bird embryo.

The present invention is directed generally to eukaryotic host cells comprising artificial endosymbionts and methods of introducing artificial endosymbionts into eukaryotic host cells. The invention provides artificial endosymbionts that introduce a phenotype to host cells that is maintained in daughter cells. The invention additionally provides eukaryotic host cells containing magnetotactic bacteria.

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.

The transgenic non-human animals are constructed, in whose genome the coding sequences of one of the animal's endogenous immunoglobulin C constant regions are replaced by human immunoglobulin C constant region coding sequences. The transgenic animal is mouse, in whose genome the C1 constant regions are replaced by the human immunoglobulin C constant regions and the C constant region is replaced by the human immunoglobulin C constant region. The transgenic mouse yields humanized IgE-secreting B cells and antigen-specific humanized IgE after immunization. The transgenic animals are employed to prepare serum containing humanized IgE, antiserum containing antigen-specific humanized IgE, and monoclonal antigen-specific humanized IgE antibodies by hybridoma and other technologies.