Six pathogenic strains ofNaegleria fowleri, two ofAcanthamoeba castellanii, and three ofAcanthamoeba polyphaga were tested in vitro for susceptibility to a variety of potentially useful therapeutic agents. Minimal motility inhibitory concentrations and minimal inhibitory concentrations were determined by a technique of subculturing pure clones of amoebae in plastic tissue culture chamber slides containing liquid axenic media and serially diluted drug, incubating at 3000 forAcanthamoeba and at 3700 forNaegleria, and observing on an inverted microscope at 6 h for inhibition of motility and at 24 and 48 h for inhibition of growth. Drug concentrations were selected on the basis of fluid levels achievable in humans. Amphotericin B, clotrimazole, and miconazole were the most effective drugs against Naegleria, whereas polymyxin B sulfate and pentamidine isethionate were somewhat effective against pathogenicAcanthamoeba. Our results suggest that amphotericin B is the most effective agent against Naegleria, but few agents are effective against Acanthamoeba.
Deoxyribonucleic acid preparations from two strains of Pseudomonas aeruginosa newly isolated from clinical specimens each contained double-stranded satellite DNA. The satellite DNA in one strain consisted of two components with buoyant densities of 1.705 and 1.712 g cm−3 and comprised 28% of the total extracted DNA. The other strain contained 15% satellite DNA which was composed of components with buoyant densities of 1.711 and 1.718 g cm−3.
Ultrastructural components of trophozoites and cysts of Acanthamoeba-Hartmannella (A-H) and Naegleria amebas have been investigated. The present report describes a technique to study the morphological features of such protozoa.The A-H strains selected were cultured for 7 days in axenic amebic media, and the Naegleria strains were cultured for 7 days in axenic media with blood. In situ fixation was accomplished by adding an equal volume of 4% Osmic Acid in Cacodylate buffer at 4¶C for one hour. Following frequent agitation, the tubes were then spun at 2500 RPM for 10 minutes to obtain a pellet. The pellets were dehydrated in graded series of alcohols (from 50% to absolute) and propylene oxide and then embedded in EPON. One micron sections were stained with Paragon (PS 1301) for thirty seconds. Thin sections were cut with a diamond knife, double stained with 5% alcoholic uranyl acetate solution and lead citrate and observed in an Hitachi-HS-8F2 electron microscope.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.