Unbalanced growth and macromolecular synthesis in Streptococcus mutans FA 1

S. J. Mattingly, J. R. Dipersio, M. L. Higgins, G. D. Shockman

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


The continued synthesis of deoxyribonucleic acid, ribonucleic acid, protein, cell wall peptidoglycan, and intracellular iodophilic polysaccharide (IPS) by S. mutans strain FA-1 after several treatments intended to inhibit protein synthesis was studied. Exponential phase cultures were: simultaneously deprived of 2 required amino acids (cystine and leucine) that are not present in the cell wall peptidoglycan of this species; deprived of required amino acids (lysine or glutamate plus glutamine) that are present in both peptidoglycan and protein; or treated with tetracycline. Each of these 3 types of treatment was accompanied by a different pattern of unbalanced growth. The patterns of unbalanced growth that accompanied treatments or differed substantially from the patterns observed previously for S. faecalis ATCC 9790, a non cariogenic organism that does not contain IPS. In contrast to S. faecalis 9790, S.mutans FA-1 failed to accumulate peptidoglycan and thicken its wall when deprived of non wall amino acids. Instead, S.mutans FA-1 continued to accumulate IPS to levels substantially higher than those found in exponential phase cells. Again, in contrast to S.faecalis, S.mutans FA-1 failed to autolyze upon deprivation of essential precursors of wall peptidoglycan. Under conditions of lysine or glutamate/glutamine deprivation, S.mutans FA-1 continued to accumulate IPS to very high levels. Treatment with tetracycline did result in peptidoglycan accumulation and wall thickening in a manner very similar to that observed previously for inhibition of protein synthesis in S.faecalis. Relatively little IPS synthesis continued after tetracycline treatment. Accumulation of IPS appeared to occur when both ribonucleic acid and peptidoglycan synthesis were severely inhibited. The observations are discussed in terms of the survival of cariogenic organisms in the oral environment.

Original languageEnglish (US)
Pages (from-to)941-948
Number of pages8
JournalInfection and immunity
Issue number3
StatePublished - 1976
Externally publishedYes

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases


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