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Squamate reptiles are amongst the most successful terrestrial vertebrate lineages, with over 10,000 species across a broad range of ecosystems. Despite their success, squamates are also amongst the least studied lineages immunologically. Recently, a universal lack of γδ T cells in squamates due to deletions of the genes encoding the T cell receptor (TCR) γ and δ chains was discovered. Here, we begin to address how the loss of γδ T cells may have impacted the evolution of the squamate immune system. Using the skinkTiliqua rugosa, we found that squamates have not significantly increased the complexity of conventional T cell receptor beta (TCRβ orTRB) chain V regions compared to that of the nearest living squamate relative, the tuatara,Sphenodon punctatusor other amniotes. Our analyses include a putative new TCR locus. This novel locus contains V, D, and J gene segments that undergo V(D)J recombination, albeit with a limited number of gene segments in most squamate species. Based on conserved residues, the predicted protein chain would be expected to form a heterodimer with TCRα. This new TCR locus appears to be derived from an ancient duplication of theTRBlocus and is homologous to the recently described T cell receptor epsilon (TRE).TREis absent from the genomes of the tuatara and all Archosaurs examined and appears squamate specific. 

Olfactory receptors (OR), expressed on olfactory neurons, mediate the sense of smell. Recently, OR have also been shown to be expressed in non-olfactory tissues, including cells of the immune system. An analysis of single-cell transcriptomes of splenocytes of the gray short-tailed opossum (Monodelphis domestica) found OR are expressed on a subset of T cells, the γμ T cells, that are unique to marsupials and monotremes. A majority of opossum γμ T cells transcriptomes contain OR family 14 transcripts, specifically, from the OR14C subfamily. Amongst the mammals, the OR14 gene family is expanded in the genomes of marsupials and monotremes, and rarer or absent in placental mammals. In summary, here we demonstrate the intriguing correlation that a family of OR genes, abundant in the genomes of marsupials and monotremes, are ectopically expressed in a particular subset of T cells unique to the marsupials and monotremes. 

Abstract Macroscale additive manufacturing has seen significant advances recently, but these advances are not yet realized for the bottom-up formation of nanoscale polymeric features. We describe a platform technology for creating crosslinked polymer features using rapid surface-initiated crosslinking and versatile macrocrosslinkers, delivered by a microfluidic-coupled atomic force microscope known as FluidFM. A crosslinkable polymer containing norbornene moieties is delivered to a catalyzed substrate where polymerization occurs, resulting in extremely rapid chemical curing of the delivered material. Due to the living crosslinking reaction, construction of lines and patterns with multiple layers is possible, showing quantitative material addition from each deposition in a method analogous to fused filament fabrication, but at the nanoscale. Print parameters influenced printed line dimensions, with the smallest lines being 450 nm across with a vertical layer resolution of 2 nm. This nanoscale 3D printing platform of reactive polymer materials has applications for device fabrication, optical systems and biotechnology.