- Volume 124, Issue 2, 1981

Cells of Bacillus subtilis NRRL B558 at early stages of sporulation contained considerable amounts of cysteic acid. The cell cysteic acid content began to increase at the onset of sporulation and was maximal when synthesis of dipicolinic acid commenced; it then decreased as sporulation advanced. Cysteic acid was synthesized from cysteine and metabolized to sulpholactate in the mother-cell cytoplasm, and the sulpholactate was then incorporated into the forespore. This metabolic change is considered to be a general phenomenon in spore-formers that contain sulpholactate in their spores.

Summary: Using the agar diffusion test of Zähner et al. (1960 ), it was demonstrated that bacilysin and a variety of di- and tri-l-peptides compete with each other for uptake into Staphylococcus aureus. Several di- and tripeptides containing l-phenylalanine produced transient growth inhibition of S. aureus NCTC 6571, but not of bacilysin-resistant mutants. The results confirm that the major peptide transport system in S. aureus recognizes both di- and tripeptides as substrates.

Summary: A new serotype (h) of Streptococcus mutans was isolated from the dental plaque of monkeys (Macaca fascicularis). Serotype h strains fermented mannitol and melibiose but not sorbitol or raffinose, failed to hydrolyse aesculin and arginine, did not produce hydrogen peroxide and were unable to grow in the presence of bacitracin at 2 units ml−1. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of whole-cell proteins showed serotype h strains to be closely related to strains of genetic group III (i.e. serotypes d and g). The serotype-specific antigen of serotype h contained glucose and galactose but was antigenically distinct from the polysaccharide antigens of serotypes a, d and g. Serotype h strains preferentially colonized developmental grooves of teeth and the proportion of serotype h in the plaque flora was greater in monkeys fed a sucrose-rich diet than in monkeys fed a starch-based diet. A serotype h strain was cariogenic for germ-free rats fed a high-sucrose diet, and serotype h strains appear to be implicated in the caries process in monkeys.