Masayoshi Totsuka

Aminopeptidase and caseinolytic activites ofMycoplasma salivarium

Aminopeptidase activity was demonstrated inMycoplasma salivarium (ATCC 23064) cells disrupted by sonic vibrations and lyophilized (crude enzymes), and weak endopeptidase or carboxypeptidase activity was also suggested.The crude enzymes were suspended in 0.1 M borate buffer, pH 8.0, containing 0.5% (w/v) sodium deoxycholate, and then the suspensions were centrifuged at 100,000g for 2 h. Thus separated, the supernatants were applied to a column of Sephacryl S-300. As a result, aminopeptidase activity was separated from caseinolytic activity, which had already been demonstrated in this organism. The aminopeptidase activity was inhibited byo-phenanthroline and stimulated by Mn2+, and the enzyme exhibited a strong affinity for leucine and arginine. On the other hand, the caseinolytic activity was inhibited considerably by o-phenanthroline and Ni2+ and slightly by diisopropyl fluorophosphate and Co2+. The caseinolytic activity was therefore believed to be due mainly to metalloproteinases and partly to serine proteinases.

Phage-receptor on the cell wall of Veillonella rodentium

Veillonellophage N2 prevented from adsorbing to Veillonella rodentium ATCC 17743 cells treated with polymyxin B, and also to lipopolysaccharides (LPSs) of the host cells treated with antibiotics. Therefore, these results indicate that receptor to phage N2 is cell wall LPSs. The LPSs of V. rodentium ATCC 17743 cells as receptor were characterized. Lipid A and total carbohydrate accounted for approximately 40% of the weight of the lipopolysaccharide complex. Heptose and 2-keto-3-deoxyoctonate were also present. Amino compounds included glucosamine, galactosamine, and glycine.

Purification and characterization of bacteriophage receptor on Veillonella rodentium cells

Veillonellophage N2 adsorbed to polysaccharides (PSs) on Veillonella rodentium ATCC 17743 cell wall, and the bacteriophage receptor contained only glucosamine. D(+)-glucosamine hydrochloride (Sigma) also adsorbed the veillonellophage N2. These results therefore indicate that the receptor to the veillonellophage N2 is cell wall PSs. The PSs of the host cells as receptor have been characterized. Glucosamine accounted for approximately 100% of the weight of the PSs. The PSs which were partially resolved by Sephadex G-75 chromatography comprised approximately four glucosamine units. Their primary structure was determined by 400 MHz n.m.r. spectroscopy. One- and two-dimensional 1H-nmr experiments showed the PS to be a branched polymer. Glucosamine linkage was detected in one of the branches.

Chemical analyses, local Shwartzman reactivity, and body weight-decreasing activity of aqueous-phenol extracts of Mycoplasma salivarium cells

Aqueous-phenol extracts of Mycoplasma salivarium ATCC 23064 cells (APM) showed demonstrable differences from lipopolysaccharides (LPSs) of Veillonella rodentium ATCC 17743. These were as follows: smaller amounts of amino sugars and an absence of 2-keto-3-deoxyoctonate; local Shwartzman reactivity and body weight-decreasing activity, even though the activities were rather weak compared with those of LPSs. Therefore, phenol-water extractive components of Mycoplasma salivarium might be of pathogenic importance in mediating damaging effects on the periodontium.