Electrophoretic assessment of taxonomic relationships within the genus Acanthamoeba (Protozoa, Amoebida)

Species identification and characterization of an Acanthamoeba strain from human cornea

The isoenzyme pattern of an Acanthamoeba, stock H-1, isolated from a patient with keratitis (Krankenhaus Heidberg, Hamburg) was compared with that of two strains of A. quina-A. lugdunensis (302-2, 312-1), two stocks of A. lenticulata (45, 89-1) and one strain of A. rhysodes (302-1). The isolated stock showed glucose-6-phosphate dehydrogenase (G-6-PDH), beta-hydroxybutyric dehydrogenase (beta-HBDH), alcohol dehydrogenase (ADH) and superoxide dismutase (SOD) isoenzyme patterns similar to those of A. quina-A. lugdunensis but their acid phosphatase (AP) patterns differed. Furthermore, cyst morphology showed that the patient-isolated stock belongs to group II of the taxonomic classification of Acanthamoeba. This stock was not thermophilic and exhibited non-pathogenic properties after its intranasal instillation into NMRI mice, whereas it killed BALB/c mice. Immunofluorescent studies revealed the presence of antibodies against Acanthamoeba in the patient's serum. Immunoblotting experiments showed that a 45-kDa protein reacted with this serum. Such an antigen was also detected in A. quina-A. lugdunensis and A. lenticulata. Lectin reactions with Canavalia ensiformis, Ricinus communis-120, Lotus tetragonolobus, Ulex europaeus I, Helix pomatia, Arachis hypogaea, Triticum vulgaris, Glycine maxima, Bauhinia purpurea and Mycoplasma gallisepticum demonstrated that only the A. lenticulata stocks could not be distinguished and that the H-1 stock was more similar to the A. lugdunensis 302-2 strain than to the other acanthamoebae.

Characterization of an axenic strain of Hartmannella vermiformis obtained from an investigation of nosocomial legionellosis

A free-living amoeba identified as Hartmannella vermiformis was isolated from a water sample obtained during an investigation of nosocomial legionellosis. Hartmannella vermiformis is known to support the intracellular multiplication of Legionella pneumophila. This strain of H. vermiformis, designated CDC-19, was cloned and established in axenic culture to develop a model for the study of the pathogenicity of legionellae. Isoenzyme patterns of axenically-cultivated strain CDC-19 were compared with two strains of H. vermiformis derived from the type strain, one axenic (ATCC 50236) and the other grown in the presence of bacteria (ATCC 30966). Enzyme patterns suggested that all three strains are assignable to the species H. vermiformis. Axenic H. vermiformis strain CDC-19 has been deposited with the American Type Culture Collection (ATCC 50237) and should prove useful in the study of protozoan-bacterial interaction.

Multiple molecular forms of Acanthamoeba lactic dehydrogenase

1. Acanthamoeba lactic dehydrogenase (D-lactate specific, EC 1.1.1.28) has been studied through the use of polyacrylamide gel electrophoresis (PAGE) and isoelectric focusing (PAGIEF). 2. Data from PAGE showed the presence of only a single macromolecular form of the enzyme in trophozoites, but PAGIEF data demonstrated that at least three LDH species occur. 3. Molecular weight determinations indicated a tetrameric assembly state for the enzyme. 4. Multiple molecular forms of the enzyme (isoenzymes) are encoded either by genes at two loci or by two alleles at a single LDH locus.