Andrés Saralegui
National Autonomous University of Mexico
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Featured researches published by Andrés Saralegui.
Nature Biotechnology | 2001
Roberto P. Stock; Alejandro Olvera; Ricardo Sánchez; Andrés Saralegui; Sonia Scarfì; Rosana Sánchez-López; Marco A. Ramos; Lidia C. Boffa; Umberto Benatti; Alejandro Alagón
Peptide nucleic acids (PNAs) may be a potent tool for gene function studies in medically important parasitic organisms, especially those that have not before been accessible to molecular genetic knockout approaches. One such organism is Entamoeba histolytica, the causative agent of amebiasis, which infects about 500 million people and is the cause of clinical disease in over 40 million each year, mainly in the tropical and subtropical world. We used PNA antisense oligomers to inhibit expression of an episomally expressed gene (neomycin phosphorotransferase, NPT) and a chromosomal gene (EhErd2, a homolog of Erd2, a marker of the Golgi system in eukaryotic cells) in axenically cultured trophozoites of E. histolytica. Measurement of NPT enzyme activity and EhErd2 protein levels, as well as measurement of cellular proliferation, revealed specific decreases in expression of the target genes, and concomitant inhibition of cell growth, in trophozoites treated with micromolar concentrations of unmodified antisense PNA oligomers.
International Journal for Parasitology | 2009
Espiridión Ramos-Martínez; Alfonso Olivos-García; Emma Saavedra; Mario Nequiz; Ernesto Sánchez; Eusebio Tello; Mohamed El-Hafidi; Andrés Saralegui; Erika Pineda; José Delgado; Irmgard Montfort; Ruy Pérez-Tamayo
Entamoeba histolytica virulence has been attributed to several amoebic molecules such as adhesins, amoebapores and cysteine proteinases, but supporting evidence is either partial or indirect. In this work we compared several in vitro and in vivo features of both virulent E. histolytica (vEh) and non-virulent E. histolytica (nvEh) axenic HM-1 IMSS strains, such as complement resistance, proteinase activity, haemolytic, phagocytic and cytotoxic capacities, survival in mice caecum, and susceptibility to O(2). The only difference observed was a higher in vitro susceptibility of nvEh to O(2). The molecular mechanism of that difference was analyzed in both groups of amoebae after high O(2) exposure. vEh O(2) resistance correlated with: (i) higher O(2) reduction (O(2)(-) and H(2)O(2) production); (ii) increased H(2)O(2) resistance and thiol peroxidase activity, and (iii) reversible pyruvate: ferredoxin oxidoreductase (PFOR) inhibition. Despite the high level of carbonylated proteins in nvEh after O(2) exposure, membrane oxidation by reactive oxygen species was not observed. These results suggest that the virulent phenotype of E. histolytica is related to the greater ability to reduce O(2) and H(2)O(2) as well as PFOR reactivation, whereas nvEh undergoes irreversible PFOR inhibition resulting in metabolic failure and amoebic death.
Journal of Cellular Biochemistry | 2005
Claudio Martínez; Rodolfo Paredes; Roberto P. Stock; Andrés Saralegui; M Merchante Andreu; Carolina Cabezón; Ricardo Ehrlich; Norbel Galanti
Echinococcus granulosus is the causative agent of hydatidosis, a major zoonoses that affects humans and herbivorous domestic animals. The disease is caused by the pressure exerted on viscera by hydatid cysts that are formed upon ingestion of E. granulosus eggs excreted by canine. Protoscoleces, larval forms infective to canine, develop asynchronously and clonally from the germinal layer (GL) of hydatid cysts. In this report, we describe the cellular organization and the appearance of differentiated structures both in nascent buds and developed protoscoleces attached to the GL. Early protoscolex morphogenesis is a highly complex and dynamic process starting from the constitution of a foramen in the early bud, around which nuclei are distributed mainly at the lateral and apical regions. Similarly, distribution of nuclei in mature protoscoleces is not homogenous but underlies three cellular territories: the suckers, the rostellar pad, and the body, that surrounds the foramen. Several nuclei are associated to calcareous corpuscles (Cc), differentiated structures that are absent in the earlier bud stages. The number of nuclei is similar from the grown, elongated bud stage to the mature protoscolex attached to the GL, strongly suggesting that there is no significant cellular proliferation during final protoscolex development. The amount of DNA per nucleus is in the same range to the one described for most other platyhelminthes. Our results point to a sequential series of events involving cell proliferation, spatial cell organization, and differentiation, starting in early buds at the GL of fertile hydatid cysts leading to mature protoscoleces infective to canine.
Cellular Microbiology | 2015
Fabiola Santos; Mario Nequiz; Nora Adriana Hernández-Cuevas; Kahory Hernández; Erika Pineda; Rusely Encalada; Nancy Guillén; Erika Rubí Luis-García; Andrés Saralegui; Emma Saavedra; Ruy Pérez-Tamayo; Alfonso Olivos-García
Adhesion to cells, cytotoxicity and proteolysis are functions required for virulence and pathogenicity of Entamoeba histolytica. However, there was no correlation between these in vitro functions and the early elimination of non‐pathogenic E. dispar and non‐virulent E. histolytica (nvEh) in experimental amoebic liver abscesses developed in hamsters. Thus, additional functions may be involved in amoebic pathogenicity and virulence. In the present study, an integral experimental assessment, including innovative technologies for analyses of amoebal pathophysiology, cell biology, biochemistry and transcriptomics, was carried out to elucidate whether other cellular processes are involved in amoebal pathogenicity and virulence. In comparison with virulent E. histolytica, the data indicated that the main reasons for the early clearance of nvEh from hamster liver are decreased intracellular H2O2 detoxification rate and deficient heat shock protein expression, whereas for E. dispar, it is a relatively lower capacity for O2 reduction. Therefore, maintenance of an intracellular hypoxic environment combined with the induction of an adequate parasite response to oxidative stress are essential requirements for Entamoeba survival in the liver, and therefore for pathogenicity.
PeerJ | 2017
Ana Gutiérrez-Preciado; Carlos Vargas-Chávez; Mariana Reyes-Prieto; Omar Federico Ordoñez; Diego Santos-Garcia; Tania Rosas-Pérez; Jorge Valdivia-Anistro; Eria A. Rebollar; Andrés Saralegui; Andrés Moya; Enrique Merino; Maria Eugenia Farias; Amparo Latorre; Valeria Souza
We report the genome sequence of Exiguobacterium chiriqhucha str. N139, isolated from a high-altitude Andean lake. Comparative genomic analyses of the Exiguobacterium genomes available suggest that our strain belongs to the same species as the previously reported E. pavilionensis str. RW-2 and Exiguobacterium str. GIC 31. We describe this species and propose the chiriqhucha name to group them. ‘Chiri qhucha’ in Quechua means ‘cold lake’, which is a common origin of these three cosmopolitan Exiguobacteria. The 2,952,588-bp E. chiriqhucha str. N139 genome contains one chromosome and three megaplasmids. The genome analysis of the Andean strain suggests the presence of enzymes that confer E. chiriqhucha str. N139 the ability to grow under multiple environmental extreme conditions, including high concentrations of different metals, high ultraviolet B radiation, scavenging for phosphorous and coping with high salinity. Moreover, the regulation of its tryptophan biosynthesis suggests that novel pathways remain to be discovered, and that these pathways might be fundamental in the amino acid metabolism of the microbial community from Laguna Negra, Argentina.
Annals of Botany | 2006
Joseph G. Dubrovsky; Martin Guttenberger; Andrés Saralegui; Selene Napsucialy-Mendivil; Boris Voigt; František Baluška; Diedrik Menzel
Experimental Parasitology | 2007
Espiridión Ramos; Alfonso Olivos-García; Mario Nequiz; Emma Saavedra; Eusebio Tello; Andrés Saralegui; Irmgard Montfort; Ruy Pérez Tamayo
Experimental Parasitology | 2005
Ricardo Sánchez; Andrés Saralegui; Alfonso Olivos-García; Carlo Scapolla; Gianluca Damonte; Rosana Sánchez-López; Alejandro Alagón; Roberto P. Stock
Archives of Medical Research | 2000
Rosana Sánchez-López; Angeles Gutiérrez; Patricia Juárez; Alejandro Olvera; Felipe Olvera; Marco A. Ramos; Ricardo Sánchez; Andrés Saralegui; Roberto P. Stock; Alejandro Alagón
PeerJ | 2017
Ana Gutiérrez-Preciado; Carlos Vargas-Chávez; Mariana Reyes-Prieto; Omar Federico Ordoñez; Diego Santos-Garcia; Tania Rosas-Pérez; Jorge Valdivia-Anistro; Eria A. Rebollar; Andrés Saralegui; Andrés Moya; Enrique Merino; Maria Eugenia Farias; Amparo Latorre; Valeria Souza