Actinomyces Sp Research Articles

Effect of saliva on coaggregation of oral Actinomyces and Streptococcus species.

Human oral actinomyces and streptococci that exhibit specific coaggregation patterns when the cells are suspended in buffer were tested for their ability to coaggregate in saliva. Of 53 paired combinations of actinomyces (Actinomyces viscosus, A. naeslundii, or Actinomyces sp. WVa 963) and streptococci (Streptococcus sanguis or S. morbillorum) that exhibited coaggregation in buffer, all but 4 pairs also coaggregated when suspended in saliva. Twenty-four pairs exhibited lactose-inhibited coaggregation in buffer: 19 of these were identical in saliva. The other five pairs either did not coaggregate or formed coaggregates that were not inhibited by lactose. Highly specific coaggregations known to occur with buffer-suspended cells (e.g., a streptococcal strain that coaggregates with a single strain of actinomyces) were unchanged when cells were suspended in saliva. These results indicate that the coaggregation properties of both oral actinomyces and streptococci are very similar with cells suspended in either saliva or coaggregation buffer. Thus, the potential for coaggregation among bacteria in the oral cavity is evident. The possible mechanisms which mediate coaggregation in saliva are discussed.

Surface ultrastructure of some oral bacteria

Adhesion of Streptococcus sanguis, Fusobacterium nucleatum and an Actinomyces sp. to enamel and epon and their interspecies cohesion was studied with scanning and transmission electron microscopy. For adhesion studies enamel or epon was coated with salivary macromolecules and then cells of S. sanguis and in some experiments also with F. nucleatum or Actinomyces sp. Cells of S. sanguis were seen scattered over the surface of a thin "pellicle" that was heavily stained, and F. nucleatum and Actinomyces sp. adhered to S. sanguis or directly to the "pellicle". For studies of cohesion S. sanguis was brought to cohere with F. nucleatum or Actinomyces sp. and then processed for transmission electron microscopy. The morphology of the cell surface structures involved was studied in negatively stained preparations or in thin sections of material treated with ruthenium red or poststained with uranyl and lead salts, phosphotungstic acid or periodic acid-thiocarbohydrazide-osmium tetroxide. S. sanguis demonstrated a fuzzy coat of fimbriae that seemed to unfold in areas of contact with other cells, while cells of F. nucleatum had 6-10 polar pilus-like fimbriae, which appeared to be instrumental in cohesion, as did a dense coat of long, slender fimbriae that covered cells of Actinomyces sp.

Nocardia species as a possible cause of ovine abortion

An instance of ovine abortion is described in which focal placental lesions were caused by a Gram-positive branching filamentous organism. The organism was present in well oxygenated tissues and so is thought more likely to have been a Nocardia sp than an Actinomyces sp.

Production of Bacterial Growth Stimulants by Heating the Medium Under Pressure.

Fulmer and Huesselmann showed the production of yeast growth stimulant by sterilizing sucrose in the presence of ammonium chloride, dipotassium phosphate and a mixture of the 2 salts. Similar results here are recorded for the following bacteria: Aerobacter faeni, Escherichia freundii, Actinomyces Sp?, A. aerogenes, Serratia Marcescens, Esch. coli, and Bacillus subtilis. The first 4 named were considerably more stimulated than the last 3. Treatment of the caramalized media with Norite A removed the coloring matter but not the stimulant. The stimulation took place at any pH value through the viable range. The results are especially interesting in view of the recent report by Lewis that the growth of several bacteria studied by him was inhibited by caramalization of the medium in the presence of nitrogenous compounds.