Abstract: The present invention relates to methods of joining two or more double-stranded (ds) or single-stranded (ss) DNA molecules of interest in vitro, wherein the distal region of the first DNA molecule and the proximal region of the second DNA molecule of each pair share a region of sequence identity. The method allows the joining of a large number of DNA fragments, in a predetermined order and orientation, without the use of restriction enzymes. It can be used, e.g., to join synthetically produced sub-fragments of a gene or genome of interest. Kits for performing the method are also disclosed. The methods of joining DNA molecules may be used to generate combinatorial libraries useful to generate, for example, optimal protein expression through codon optimization, gene optimization, and pathway optimization.

Abstract: Compositions and methods are disclosed herein for cloning a synthetic or a semi-synthetic donor genome in a heterologous host cell. In one embodiment, the donor genome can be further modified within a host cell. Modified or unmodified genomes can be further isolated from the host cell and transferred to a recipient cell. Methods disclosed herein can be used to alter donor genomes from intractable donor cells in more tractable host cells.

Abstract: Compositions and methods are disclosed herein for cloning a donor genome in a heterologous host cell. In one embodiment, the donor genome can be further modified within a host cell. Modified or unmodified genomes can be further isolated from the host cell and transferred to a recipient cell. Methods disclosed herein can be used to alter donor genomes from intractable donor cells in more tractable host cells.

Abstract: The present invention relates to methods of joining two or more double-stranded (ds) or single-stranded (ss) DNA molecules of interest in vitro, wherein the distal region of the first DNA molecule and the proximal region of the second DNA molecule of each pair share a region of sequence identity. The method allows the joining of a large number of DNA fragments, in a predetermined order and orientation, without the use of restriction enzymes. It can be used, e.g., to join synthetically produced sub-fragments of a gene or genome of interest. Kits for performing the method are also disclosed. The methods of joining DNA molecules may be used to generate combinatorial libraries useful to generate, for example, optimal protein expression through codon optimization, gene optimization, and pathway optimization.

Abstract: A method to assemble any desired nucleic acid molecule by combining cassettes in vitro to form assemblies which are further combined in vivo, or by assembling large numbers of DNA fragments by recombination in a yeast culture to obtain desired DNA molecules of substantial size is described.

Abstract: A method for producing horseshoe crab amebocytes in vitro by isolating amebocyte producing tissue from the gill flaps of horseshoe crabs, especially Limulus polyphemus. In contrast to all previous attempts to isolate and culture amebocytes from Limulus for the production of pyrogen-sensitive lysate, an effective method and means has been developed utilizing the discovery that the gill flaps are the source of the cells which differentiate into competent amebocytes. Once isolated, the tissue can be cultured long term in vitro on an artificial surface or as part of the gill flap leaflets, opened along one edge to allow access of the media to the developing amebocytes. Amebocytes are removed from the gill flaps by pulsing with Limulus serum, copper sulfate, detergent, or combinations thereof.