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Pathogenic Naegleria fowleri is the causative agent of fatal human amoebic meningoencephalitis. The protozoan is ubiquitous in nature, and its presence is enhanced by thermal additions. In this investigation, water and sediments from a newly created cooling lake were quantitatively analyzed for the presence of thermophilic amoebae, thermophilic Naegleria(More)
On SDS-PAGE, solubilized and proteinase K treated preparations of Neisseria gonorrhoeae strain BS4 (agar) showed differences in silver stained lipopolysaccharide (LPS) patterns, before and after induction to resistance to serum killing by incubation for 3 h at 37 degrees C with low Mr fractions from lysates of guinea pig red blood cells. Preparations from(More)
Recently evidence has been obtained that a minute amount of cytidine 5'-monophospho-N-acetyl neuraminic acid (CMP-NANA) or a closely related compound is the low Mr factor in human red blood cells which induces Neisseria gonorrhoeae (BS4(agar] to resistance to killing by fresh human serum. Induction of gonococci to resistance by both CMP-NANA and(More)
The recent demonstration of a host-derived inducer of gonococcal resistance to complement-mediated killing by human serum in purified serum and red blood cell fractions, which contained small glucopeptides with cysteine as one of the constituent amino acids, prompted an investigation of Neisseria gonorrhoeae for thioglucosidase activity. This involved an(More)
TNT was mutagenic for Salmonella typhimurium without the need of a rat liver metabolic activation system (S9). The mutagenic potency of TNT decreased in proportion to the number of nitro groups that were reduced to the amino form. The presence of a nitro group on the 4 position of the diamino congener is necessary for mutagenicity. Among the active(More)
1. The effect of flavonoids on coumarin 7-hydroxylation, an activity marker of an important human liver cytochrome P450 isoform, cytochrome P450 2A6 (CYP2A6), was investigated in this study. 2. Coumarin 7-hydroxylase activity was measured fluorometrically in reaction mixtures containing cDNA-expressed CYP2A6, nicotinamide adenine dinucleotide phosphate(More)
The toxicity of 16 metal salts to Chinese hamster ovary (CHO) cells was determined by measuring the cloning efficiency (CE) of CHO cells after exposure to the metals. CHO cells differed by a factor of 10(5) to 10(6) in their toxic response to these metal salts. While Cd(II) was the most toxic ion, Mg(II) exhibited the least toxicity based on either CE50(More)
Serum-susceptible (SS) Neisseria gonorrhoeae were induced to resistance (SR) to complement-mediated killing by fresh human serum (FHS) by a small-Mr factor(s) from guinea-pig blood in 3 h at 37 degrees C, but not in the presence of bacteriostatic concentrations of chloramphenicol or neomycin, indicating that proteins mediated the acquisition of resistance.(More)