Haemophilus ducreyi strain ATCC 27722 contains a genetic element with homology to the vibrio RS1 element that can replicate as a plasmid and confer NAD independence on haemophilus influenzae.

The nucleotide sequence of pNAD1, a plasmid from Haemophilus ducreyi identified on the basis of its ability to confer NAD independence on Actinobacillus pleuropneumoniae and H. influenzae, has been determined. In addition to containing the nadV gene, the plasmid contains homologues of the rstR and rstA genes, genes encoding repressor and replication proteins, respectively, in the Vibrio CTXphi and the Vibrio RS1 element, suggesting a single-stranded bacteriophage origin for pNAD1.

Pre-B-cell colony-enhancing factor, whose expression is up-regulated in activated lymphocytes, is a nicotinamide phosphoribosyltransferase, a cytosolic enzyme involved in NAD biosynthesis.

The murine homologue of the previously identified human "pre-B-cell colony-enhancing factor" (PBEF) gene coding for a putative cytokine has been identified by screening a subtractive library enriched in genes expressed in activated T lymphocytes. Unlike most cytokine genes known to date, the PBEF gene is ubiquitously expressed in lymphoid and non-lymphoid tissues and displays significant homology with genes from primitive metazoans (marine sponges) and prokaryotic organisms. Recently, a bacterial protein encoded by nadV, a gene from the prokaryote Haemophilus ducreyi displaying significant homology with PBEF, has been identified as a nicotinamide phosphoribosyltranferase (NAmPRTase), an enzyme involved in nicotinamide adenine dinucleotide (NAD) biosynthesis.

ohr, Encoding an organic hydroperoxide reductase, is an in vivo-induced gene in Actinobacillus pleuropneumoniae.

Actinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia, a disease characterized by pulmonary necrosis and hemorrhage caused in part by neutrophil degranulation. In an effort to understand the pathogenesis of this disease, we have developed an in vivo expression technology (IVET) system to identify genes that are specifically up-regulated during infection. One of the genes that we have identified as being induced in vivo is ohr, encoding organic hydroperoxide reductase, an enzyme that could play a role in detoxification of organic hydroperoxides generated during infection.