Abstract: The present invention provides compositions and methods related to the production of fatty acids, such as triglycerides with genetically engineered cells, such as algae.

Abstract: Signal propagation apparatus is formed with a waveguide cavity for propagating first and second electromagnetic signals respectively having first and second electric fields that are distinguished outside the cavity by first and second polarizations, for example orthogonal polarizations, one vertical and one horizontal. Within the cavity, the electric field lines are curved and cross one another at angles that vary as a function of location within the cavity. A pair of probes are mounted within the cavity in spaced-apart relation to each other and have orientations that differ from the orientations of the electric fields outside the cavity. In order to send or transmit signals having electric fields that are respectively vertically and horizontally polarized, for example, thereby forming an angle of 90.degree. with respect to each other, the probes lie in planes forming a dihedral angle of about 80.degree..