The short isoform of the CEACAM1 receptor in intestinal T cells regulates mucosal immunity and homeostasis via Tfh cell induction.

Carcinoembryonic antigen cell adhesion molecule like I (CEACAM1) is expressed on activated T cells and signals through either a long (L) cytoplasmic tail containing immune receptor tyrosine based inhibitory motifs, which provide inhibitory function, or a short (S) cytoplasmic tail with an unknown role. Previous studies on peripheral T cells show that CEACAM1-L isoforms predominate with little to no detectable CEACAM1-S isoforms in mouse and human. We show here that this was not the case in tissue resident T cells of intestines and gut associated lymphoid tissues, which demonstrated predominant expression of CEACAM1-S isoforms relative to CEACAM1-L isoforms in human and mouse.

The aminoglycoside 6'-N-acetyltransferase type Ib encoded by Tn1331 is evenly distributed within the cell's cytoplasm.

The multiresistance transposon Tn1331, which mediates resistance to several aminoglycosides and beta-lactams, includes the aac(6')-Ib, aadA1, bla(OXA-9), and bla(TEM-1) genes. The nucleotide sequence of aac(6')-Ib includes a region identical to that of the bla(TEM-1) gene. This region encompasses the promoter and the initiation codon followed by 15 nucleotides.

Osmoregulation of dimer resolution at the plasmid pJHCMW1 mwr locus by Escherichia coli XerCD recombination.

Xer-mediated dimer resolution at the mwr site of plasmid pJHCMW1 is osmoregulated in Escherichia coli. Whereas under low-salt conditions, the site-specific recombination reaction is efficient, under high-salt conditions, it proceeds inefficiently. Regulation of dimer resolution is independent of H-NS and is mediated by changes in osmolarity rather than ionic effects.