ALTERATION OF TRANSFER-RIBONUCLEIC-ACID OF NEISSERIA-MENINGITIDIS DURING GROWTH IN THE PRESENCE OF HUMAN TRANSFERRIN

Iron-related tRNA alterations have been shown to occur in several path ogens but nothing has been reported about the effect of iron on mening ococcal tRNA. The chromatographic elution profile of H-3-tryptophan-tR NA(trp) from a Neisseria meningitidis strain grown under different con ditions was examined. The profile showed an early (P1) and a late (P2) eluting species of tRNA(trp), but the proportion of the two species v aried under different growth conditions. The elution profile of trp-tR NA(trP) from bacteria grown in iron-sufficient Mueller Hinton broth yi elded a minor P1 species and a major P2 species, whereas under iron-re stricted growth induced by desferrioxamine, the pattern was one of a m ajor P1 species and minor P2 species. Iron-restriction induced by huma n transferrin (HTF) resulted in almost equal amounts of the two tRNA(t rp) Species (P1 congruent-to P2). Differences in the proportions of th e tRNA species were also found between cells grown in liquid medium (P 1 much less than P2) and on the same medium solidified with agar (P1 m uch greater than P2). The growth phase of the bacteria did not have an y effect on the tRNA(trP) elution profile. Changes in tRNA(trp) induce d by HTF were readily and completely reversible when the cells were tr ansferred to an iron-rich medium, but those induced by desferrioxamine remained irreversible for a long period (16 h) after such transfer.