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Trichomonas vaginalis possesses a membrane-associated neuraminidase activity that is released into culture medium during its growth in vitro. The neuraminidase shows an optimum pH of 4.5 and a Km of 0.15 mM for 2'-(4-methylumbelliferyl)-alpha-D-N-acetyl-neuraminic acid as a substrate. This enzyme releases mainly alpha-2,3-linked sialic acid because it is(More)
The in vitro cytopathic effect of Trichomonas vaginalis on epithelial cells was explored through the interaction of trophozoites of the virulent strain GT-10 with MDCK monolayers. The interaction was analyzed through electrophysiology, video microscopy, and transmission and scanning electron microscopy. Electrical measurements revealed that living parasites(More)
The complete sequence of morphologic events during amebic liver abscess formation in the hamster has been studied, from the lodgement of amebas in the hepatic sinusoids to the development of extensive liver necrosis. Following intraportal inoculation of live amebas, the early stages of the lesion (from 1 to 12 hours) were characterized by acute cellular(More)
The morphological features of early intestinal ulcerations induced in rodents with axenic cultures of Entamoeba histolytica were studied by scanning and transmission electron microscopy. Amebas did not attach to the luminal surface of the mucosa except at interglandular regions, where parasites penetrated apparently through pseudopodial movement. Once in(More)
The analysis of behavior of man in the field of biology is carried out through bioethics, considered the science of the survival. In the microbiology, there are numerous discoveries related with pathogenic microorganisms, including those that can be used as weapons in a biological war or in an attack considered bioterrorism. The scientist involved in(More)
Bacterial reporter assays are powerful tools used to study the effect of different compounds that affect the physiology of cellular processes. Most bacterial reporters are luciferase based and can be monitored in real time. In the present study we designed and implemented two sets of Escherichia coli bacterial reporter assays, using a multicopy plasmid(More)
Serine proteases are one of the biologically most important and widely distributed enzyme families. A protease capable of degrading the substrate Suc-AAF-AMC was isolated from axenically grown trophozoites of Entamoeba histolytica. The enzyme was purified by ion-exchange chromatography and electroelution, and appeared on 2D-PAGE as a spot of 60 kDa and pI(More)
A new experimental model for the production of early stages of invasive intestinal amebiasis in hamsters or guinea pigs with axenic or monoxenic cultures of Entamoeba histolytica of the HM1:IMSS strain is reported. The model is called the washed-closed cecal loop, because it involves the washing out of the cecum contents of conventionally raised animals and(More)
PEHPS medium, developed for axenic cultivation of Entamoeba histolytica and E. invadens, was also capable of supporting the growth of a Trichomonas vaginalis strain, with an inoculum of 1 to 100 trichomonads/ml. The logarithmic growth phase in PEHPS or in TYI-S-33 medium lasted 72 h; yield (3.33 +/- 0.56 x 10(6) trichomonads/ml), duplication time (4.27 h),(More)