Waddlia chondrophila, a Potential Agent of Human Fetal Death

We investigated the zoonotic potential of Waddlia chondrophila, a new Chlamydia-like abortigenic agent in ruminants. Anti-Waddlia antibody reactivity was tested by immunofluorescence and Western blot. Waddlia seroprevalence was higher in women who had had sporadic and recurrent miscarriages than in control women (p<0.001). Waddlia spp. may represent a cause of human fetal loss

Caractérisation de deux composants du cytosquelette de Trypanosoma brucei

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Caractérisation de deux composants du cytosquelette de Trypanosoma brucei

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Characterization of a coiled coil protein present in the basal body of Trypanosoma brucei.

TBBC (for Trypanosoma brucei basal body component) is a unique gene transcribed in a 4.8 kb mRNA encoding a 1,410 amino acid protein that consists almost entirely of a coiled coil structure. This protein appeared to localize in the basal body, with an accessory presence at the posterior end of the cell, the nucleus and over the flagellum. Since the two other known components of the trypanosome basal body are (gamma)-tubulin and an uncharacterized component termed BBA4 we performed double immunofluorescence experiments with anti-TBBC and either anti-BBA4 or anti-(gamma)-tubulin antibodies. These three components did not colocalize but were very closely associated, BBA4 being the most proximal to the kinetoplast DNA. Anti-TBBC antibodies detected a 170 kDa protein in western blots of total HeLa cell extracts. Moreover, these antibodies stained the centriole of HeLa and COS cells as well as the centriole of mouse spermatozoa, indicating that a TBBC-like centriolar component has been conserved during the evolution of eukaryotes.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

A differential role for actin during the life cycle of Trypanosoma brucei

Actin is expressed at similar levels but in different locations in bloodstream and procyclic forms of Trypanosoma brucei. In bloodstream forms actin colocalizes with the highly polarized endocytic pathway, whereas in procyclic forms it is distributed throughout the cell. RNA interference demonstrated that in bloodstream forms, actin is an essential protein. Depletion of actin resulted in a rapid arrest of cell division, termination of vesicular traffic from the flagellar pocket membrane leading to gross enlargement of the pocket, loss of endocytic activity and eventually cell death. These results indicate that actin is required for the formation of coated vesicles from the flagellar pocket membrane, which is the first step in the endocytic pathway. Although loss of actin in procyclic cells did not affect growth, the trans region of the Golgi became distorted and enlarged and appeared to give rise to a heterogeneous population of vesicles. However, the flagellar pocket was not affected. These findings suggest that trypanosomes have different functional requirements for actin during the bloodstream and procyclic phases of the life cycle

Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality

An increasing number of microorganisms, including bacteria but also viruses and eukaryotes, have been described as benefiting from interaction with free-living amoebae (FLA). Beneficial interaction can be due to resistance to predation conferring ecological advantage, intracellular survival and/or intracellular proliferation. This review highlights the potential risk associated with amoebae by listing all known pathogenic microbial species for which growth and/or survival promotion by FLA (mainly Acanthamoeba spp.) has been demonstrated. It focuses on the susceptibility of amoebal and intra-amoebal bacteria to various categories of biocides, the known mechanisms of action of these biocides against trophozoites and cysts and the various methods used to demonstrate efficacy of treatments against FLA. Brief descriptions of FLA ecology and prevalence in domestic/institutional water systems and their intrinsic pathogenicity are also presented. The intention is to provide an informed opinion on the environmental risks associated with the presence of FLA and on the survival of cysts following biocidal treatments, while also highlighting the need to conduct research on the roles of amoebae in aquatic ecosystems