This protocol was used to\u00a0express a nourseothricin (nou\/nat) resistance gene and\u00a0a gene encoding a silaffin precursor TpSil3p-APEX2 fusion protein in Thalassiosira pseudonana\u00a0(Tp) strain CCMP1335\u00a0using conjugation by largely following Karas et al. (2015). In addition to the protocol, I am listing some of my observations working with this diatom species. Please check the 'Before start' and 'Guidelines' sections for more information\u00a0including a list of Tp\u00a0episomes I've constructed and which are available upon request. For additional background on my overacrching experimental aim, please refer to this document.\u00a01.\u00a0E. V. Armbrust, The Genome of the Diatom Thalassiosira Pseudonana: Ecology, Evolution, and Metabolism. Science. 306, 79\u201386 (2004).2. B. J. Karas et al., Designer diatom episomes delivered by bacterial conjugation. Nat. Commun. 6, 6925 (2015).Keeping in mind that diatom episomes contain a yeast centromere, it would be very interesting to see if conjugation could be adapted to organisms beyond diatoms.