Bacteroides gingivalis381株の産生する培養上清中の菌凝集素の分離とその性状

抄録

Bacteroides gingivalis possesses adhesive properties enabling it to bind to sulcular epithelium and saliva-coated hydroxyapatite and to aggregate oral gram-positive organisms. This study deals with the isolation and some properties of adhesin aggregating Streptococcus mitis ATCC 9811 from culture medium of B. gingivalis 381. The inhibitory effect of various compounds on the aggregation was also studied.
B. gingivalis 381 was anaerobically grown in trypticase soy broth supplemented with yeast extract, hemin and menadion at 37°C. The bacterial binding adhesin (BBA) was isolated from the culture fluid by ultracentrifugation followed by gel filtration on Sepharose CL-4B and by affinity chromatography on arginine agarose. Through these procedures, the BBA was purified about 5800 times from culture fluid based on the specific aggregating activity assayed by serial dilution using a microtiter plate. By electron micrographs of negatively stained BBA preparations, the structures resembling fimbriae were never observed. To screen sugars, amino acids and other substances for inhibition of aggregation of the BBA, the aggregation-inhibition test was performed by turbidimetric assay. The activity of BBA was inhibited by L-arginine and arginine-containing peptides although the activity was unaffected by the sugars tested. These results suggest that arginine may function as contact residue between the BBA and S. mitis ATCC 9811 during the aggregation.