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Field emission scanning electron microscopy (FE-SEM) provides a range of strategies for investigating the structural organization of biological systems, varying from isolated macromolecules to tissue organization and whole organisms. This review covers some of the results so far obtained using FE-SEM observation and various protocols of sample fixation to(More)
By means of immunofluorescence, immunoelectron microscopy and immunoblotting, we show that polyglycylation, a posttranslational modification of tubulin widely spread among eukaryotes, is present in the diplomonad, Giardia lamblia, a putative ancestral cell possessing a highly developed microtubular cytoskeleton. This modification was recently discovered in(More)
Sox2 is an important transcriptional regulator in embryonic and adult stem cells. Recently, Sox2 was identified as an oncogene in many endodermal cancers, including colon cancer. There is great interest in how Sox2 cooperates with other transcription factors to regulate stem cell renewal, differentiation, and reprogramming. However, we still lack a general(More)
Glioblastomas (GBMs) are devastating tumors of the central nervous system, with a poor prognosis of 1-year survival. This results from a high resistance of GBM tumor cells to current therapeutic options, including etoposide (VP-16). Understanding resistance mechanisms may thus open new therapeutic avenues. VP-16 is a topoisomerase inhibitor that causes(More)
Astrocytes, members of the glial family, interact through the exchange of soluble factors or by directly contacting neurons and other brain cells, such as microglia and endothelial cells. Astrocytic projections interact with vessels and act as additional elements of the Blood Brain Barrier (BBB). By mechanisms not fully understood, astrocytes can undergo(More)
Suramin has been previously reported to inhibit distinct cell enzymes and to affect the synthesis and distribution of cytoskeleton proteins. Our study indicates that prolonged incubation of Trypanosoma cruzi infected-LLC-MK2 cells in the presence of 500 microM suramin during the intracellular development of the parasite caused morphological changes on(More)
The association of high resolution field emission scanning electron microscopy (FESEM), with a more efficient system of secondary electron (SE) collection and in-lens specimen position, provided a great improvement in the specimen's topographical contrast and in the generation of high-resolution images. In addition, images obtained with the use of the(More)
Giardia lamblia is a flagellated protozoan of great medical and biological importance. It is the causative agent of giardiasis, one of the most prevalent diarrheal disease both in developed and third-world countries. Morphological studies have shown that G. lamblia does not present structures such as peroxisomes, mitochondria, and a well-elaborated Golgi(More)
Giardia lamblia is a diplomonad that parasitizes the small intestine of vertebrates. The trophozoite is multiflagellar and its cytoskeleton presents a complex organization of microtubular structures. One of these, the adhesive disk, consists of a microtubular spiral. The median body, whose function is not yet determined, is also composed by microtubules.(More)
The Giardia lamblia life cycle is characterized by two phases during which two major cell differentiation processes take place: encystation and excystation. During encystation, the trophozoites transform into cysts, the resistance form. Once ingested by a susceptible host, the cysts are stimulated to excyst in the stomach, and the excysted trophozoites(More)