This investigation characterized and compared outer membrane proteins (OMP) of the closely related Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus by means of SDS-PAGE patterns and reactions on immunoblots with rabbit antiserum against A. actinomycetemcomitans FDC Y4. Reactions with serum from a patient with Papillon Lefévre syndrome (PLS), from whom periodontal wild strains of A. actinomycetemcomitans had been isolated, were also studied. OMP were purified with selective solubilization from lyophilized cells of 10 wild and 4 reference strains of A. actinomycetemcomitans and 4 reference strains of H. aphrophilus. OMP profiles from wild and reference strains of A. actinomycetemcomitans were similar while those from A. actinomycetemcomitans and H. aphrophilus differed. The most prominent difference was absence of a heat modifiable protein in H. aphrophilus strains. Immunoblotting revealed strong common antigens in most strains, including a heat modifiable protein with mol wt 34 kDa, as well as a 29 kDa and a 16.5 kDa protein. Treatment with pronase and sodium periodate confirmed the protein nature of the major OMP antigens.

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– The diet and the prevalence of dental caries in a group of Alaskan inland Eskimos have been studied on two occasions. Considerable changes in living habits had occurred during the 8–10 intervening years. A marked change in diet was noted. The percentage of total calories obtained from protein had decreased by about 50 % and that from carbohydrate increased by nearly 50 %. The change in diet was accompanied by a drastic increase in the prevalence of dental caries. The DMFT rate for primary teeth showed an almost 90 % increase and the DMFT rate for permanent teeth of persons over 6 years of age exhibited a four‐fold increase. The most dramatic change was observed in individuals 30 years of age or older. In this previously caries‐free group, all subjects had developed caries in the course of 8 years.

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SUMMARYPhenol-water extracted lipopolysaccharides (LPS) from Bacteroides fragilis NCTC 9343 did not contain heptose or 2-keto-3-deoxy-octonate. The sugar components identified were glucosamine, galactosamine, glucose, galactose, fucose, rhamnose and traces of mannose. An unidentified amino compound was found. The preparations were free of nucleic acids and protein constituted only a minor fraction of the LPS. The LPS preparations had endotoxic effect when tested in rabbits, but the endotoxic potency was low. I N T R O D U C T I O NEndotoxic lipopolysaccharide (LPS) from Bacteroides melaninogenicus lacks heptose and 2-keto-3-deoxy-octonate (KDO) (Hofstad, I 968). With a few exceptions (Hickman & Ashwell, 1966;Volk, 1966;Kasai & Nowotny, 1967;Adams, Tornabene & Yaguchi, 1969) these sugars are present as essential constituents in LPS from aerobic Gram-negative bacteria (Osborn, 1963 ; Luderitz, Staub & Westphal, 1966). The unexpected finding that both sugars were absent in B. melaninogenicus LPS has prompted a survey of the chemistry of LPS from related non-sporing anaerobic Gram-negative bacteria. The present report deals with the chemical composition of LPS from B. fragilis NCTC 9343. METHODSBacterial strains. The Bacteroides fragilis strain NCTC 9343 was furnished by Dr Ella Barnes, Food Research Institute, Norwich, England. Cultivation was performed as described earlier (Hofstad, 1968) in an enriched fluid medium based on beef extract.Extraction of LPS. Extraction of LPS with phenol-water (Westphal, Liideritz & Bister, I 952) and further purification by ultracentrifugation were carried out as before (Hofstad, I 968). Extractions were made at room temperature from acetonedried whole cells. After ultracentrifugation (~oo,ooo g for I hr) the pellet was suspended in 0.1 M phosphate buffer pH 7.0 containing ribonuclease (5 x cryst., ex-bovine pancreas, Sigma Chemical Company, St Louis, Missouri, U.S. A.) and deoxyribonuclease (25 yo activity of crystalline material deoxyribonuclease, ex-bovine pancreas, L. Light & Co. Ltd., Colnbrook, England) to give an enzyme:substrate ratio of about I : 50, and incubated at 37" for I hr. The ultracentrifugation was repeated, and the washed LPS finally taken up in distilled water and lyophilized.