Phylogenetic and molecular analysis of food-borne shiga toxin-producing Escherichia coli.

Seventy-five food-associated Shiga toxin-producing Escherichia coli (STEC) strains were analyzed by molecular and phylogenetic methods to describe their pathogenic potential. The presence of the locus of proteolysis activity (LPA), the chromosomal pathogenicity island (PAI) PAI ICL3, and the autotransporter-encoding gene sabA was examined by PCR. Furthermore, the occupation of the chromosomal integration sites of the locus of enterocyte effacement (LEE), selC, pheU, and pheV, as well as the Stx phage integration sites yehV, yecE, wrbA, z2577, and ssrA, was analyzed.

Synthetic quartz with high ultraviolet transmission.

Quartz has been synthesized under hydrothermal conditions at rates of 1.78 mm/day in the presence of LiNO(2) in Ag lined and Ag plated systems, and it is shown that such quartz has optical transmission between 1500 A and 3 micro equal, and in some cases superior to, natural quartz. The uv cutoff at about 1500 A has been shown to be associated with Fe whose concentration may be reduced by procedures that reduce the concentration of charge compensating H+ in the lattice (growth in LiNO(2)) and by procedures which reduce the concentration of Fe in solutions (inert conditions).