The presence of A. actinomycetemcomitans in atheromatous plaques and the periodontal pockets of the same patients could indicate a role for periodontal pathogenic bacteria in the atherosclerosis disease process.

No abstract

The bacteriocin of Pseudomonas sp. strain R10 was active in vitro against several enteropathogenic bacteria: enterotoxigenic Escherichia coli, Salmonella typhimurium, Salmonella typhi, Shigella flexneri and Shigella sonnei. Pseudomonas sp. R10 was studied for 5 d in an aquatic system in the presence of strains of the enteropathogenic species mentioned. All the target strains were inhibited in the presence of bacteriocinogenic Pseudomonas sp. R10 and the highest antibacterial action was observed on the second day. Similar results were obtained with the partially purified bacteriocin, although the greatest bactericidal action, in all the studied target strains, was observed on the first day and the bacterial recounts were slightly higher overall.

Aims:  To determine the production of bacteriocin by Shigella flexneri strains, to relate their production to the presence of dysenteric diarrhoea and to asses the genetic determination of the bacteriocin. Methods and Results:  One hundred and sixteen strains of Sh. flexneri were isolated from patients with diarrhoea and 49 of them produced bacteriocin active against several Escherichia coli and abacteriocinogenic Sh. flexneri strains. The extrachromosomal DNA isolated from bacteriocinogenic Sh. flexneri strains were used as a substrate to transform E. coli HB‐101 cells by means of electroporation. Conclusions:  Only the Sh. flexneri strains isolated from dysenteric diarrhoea produced bacteriocin. It was demonstrated that a plasmid of approx. 3 kb was responsible for the genetic determination of these anti‐bacterial substances. Significance and Impact of the Study:  A 3‐kb plasmid that harboured information for the production of bacteriocin by Sh. flexneri strains was described. The production of this bacteriocin may be related to dysenteric diarrhoea produced by these bacterial strains.

Treatment of purified pig kidney fructose 1,6diphosphatase with pyridoxal 5'-phosphate followed by reduction with sodium borohydride leads to the formation of active pyridoxyl phosphate derivatives of the enzyme, showing diminished sensitivities to allosteric AMP inhibition and to high substrate inhibition (Marcus, F., and Hubert, E. (1968), J. Biol. Chem. 243, 4923). These alterations were not observed when modification with pyridoxal 5'-phosphate was carried out in the presence of substrate plus AMP. However, when fructose 1,6-diphosphatase was modified with pyridoxal 5'phosphate in the presence of fructose 1,6-diphosphate, active pyridoxyl phosphate derivatives of the enzyme (containing up to approximately 4 moles of pyridoxyl phosphate/mole of enzyme) were obtained. Under these conditions, only the regulatory properties of fructose 1,6-diphosphatase were