RESUMEN
We report here the third case of Acanthamoeba keratitis discovered in France in a 30 year-old man wearing soft contact lenses. Amoebas of Acanthamoeba genus could be isolated twice from his corneal ulcer with simple ocular swabs. Owing to medical treatment alone, a successful healing of his eye was obtained. The isolated strain was studied morphologically and biochemically: the cysts observed microscopically after silver stain possessed less than six arms surrounded by a non reticulated ectocyst and belonged to group II defined by Pussard and Pons. But the isoenzymatic study of the ocular strain by isofocusing did not allow us to identify it with any one of the 18 reference strains used, although these represent 14 different described species.
Asunto(s)
Queratitis por Acanthamoeba/parasitología , Acanthamoeba/citología , Acanthamoeba/enzimología , Isoenzimas/análisis , Acanthamoeba/aislamiento & purificación , Adulto , Animales , Córnea/parasitología , Humanos , Masculino , Tinción con Nitrato de PlataRESUMEN
Pernina chaumonti, n.g., n.sp., is an amoeba isolated from an industrial culture of marine and unicellular red algae of the genus Porphyridium (Rhodophyceae). This phycophagous and bacteriophagous amoeba managed to develop on an agar medium containing 29%. of NaCl. The study in light and electron microscopy revealed that this amoeba possesses characters of the family Vahlkampfiidae, especially a nuclear division of the promitotic type. Absence of development on culture medium without NaCl, as well as the particularities of the promitosis and the cyst structure encouraged us to propose a new genus whose systematic position should be later defined in comparison with the families Gruberellidae and Vahlkampfiidae.
RESUMEN
In a previous work, Levrat et al. [21] showed an enhancement of the production of pyoverdin (siderophore) by Pseudomonas putida in the presence of amoeba. To explain the mechanism of stimulation, the hypothesis of production of stimulatory factors by amoeba was proposed. Filtrates of both mixed culture of bacteria and amoeba (Pseudomonas putida + Acanthamoeba castellanii) and of axenic culture of amoeba were added to the culture medium of Pseudomonas. The production of pyoverdin was increased in the presence of the filtrates. The maximum stimulation was observed with a 6 to 8 day old mixed culture filtrate at 2% final concentration. A higher amount of filtrate did not enhance the stimulation. General metabolisms like ammonium production or respiration were also enhanced in the presence of filtrate of mixed cultures. Filtrates of axenic culture of amoeba were also able to stimulate the production of pyoverdin by Pseudomonas. This stimulation of the bacterial metabolism was not correlated with a higher growth of the bacterial population. Then, the enhancement of the bacterial metabolic activity was not due to a rapid recycling of the bacterial biomass but rather to a production of stimulatory factors by amoeba.