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Miranda Contreras L.,University of Zulia | Delgado Luengo W.,University of Zulia | Zerpa N.,Fundacion Institute Estudios Avanzados | Chacin Hernandez J.,University of Zulia | And 2 more authors.
Anales de Pediatria | Year: 2012

Introduction: Neuronal ceroid lipofuscinoses are a group of inherited autosomal recessive lysosomal diseases, most commonly found in infancy. These are neuropathologically characterised by accumulation of an autofluorescent lipopigment in neurons and other cells. This condition is clinically characterised by loss of motor and cognitive skills, lack of motor coordination, ataxia, progressive visual impairment, behavioural changes; seizures of difficult to manage seizures, particularly myoclonic, and premature death. Ten clinical forms have been described, one of which is late infantile where clinical signs begin between two and four years. The gene responsible for this disease is located at 11p15 locus, and the enzyme encoded by this gene is the tripeptidyl peptidase 1. Patients and methods: We standardised the technique for the enzymatic diagnosis of late infantile neuronal ceroid lipofuscinoses from dried blood on filter paper card in 76 healthy individuals adults and children in order to establish a normal range in the Venezuelan population. The tripeptidyl peptidase activity was also determined in 9 patients with a clinical diagnosis of late infantile neuronal ceroid lipofuscinoses. Results: Six of the samples showed activity lower than the lowest control value (0.11 to 0.45 nmol/spot) from healthy controls of infantile age, confirming the enzymatic diagnosis. Three of the 14 parent samples analysed showed values in the heterozygote ranges. Conclusions: The enzymatic diagnosis of late infantile neuronal ceroid lipofuscinoses from dried blood on filter paper card is a rapid, easier, less expensive and accurate molecular diagnosis tool. © 2011 Asociación Española de Pediatría. Published by Elsevier España, S.L. All rights reserved. Source


Chiurillo M.A.,University Centroccidental Lisandro Alvarado | Cortez D.R.,University of Sao Paulo | Lima F.M.,University of Sao Paulo | Cortez C.,University of Sao Paulo | And 5 more authors.
Infection, Genetics and Evolution | Year: 2016

Trans-sialidase (TS) is a polymorphic protein superfamily described in members of the protozoan genus Trypanosoma. Of the eight TS groups recently described, TS group I proteins (some of which have catalytic activity) are present in the distantly related Trypanosoma brucei and Trypanosoma cruzi phylogenetic clades, whereas other TS groups have only been described in some species belonging to the T. cruzi clade. In the present study we analyzed the repertoire, distribution and phylogenetic relationships of TS genes among species of the T. cruzi clade based on sequence similarity, multiple sequence alignment and tree-reconstruction approaches using TS sequences obtained with the aid of PCR-based strategies or retrieved from genome databases. We included the following representative isolates of the T. cruzi clade from South America: T. cruzi, T. cruzi Tcbat, Trypanosoma cruzi marinkellei, Trypanosoma dionisii, Trypanosoma rangeli and Trypanosoma conorhini. The cloned sequences encoded conserved TS protein motifs Asp-box and VTVxNVxLYNR but lacked the FRIP motif (conserved in TS group I). The T. conorhini sequences were the most divergent. The hybridization patterns of TS probes with chromosomal bands confirmed the abundance of these sequences in species in the T. cruzi clade. Divergence and relationship analysis placed most of the TS sequences in the groups defined in T. cruzi. Further examination of members of TS group II, which includes T. cruzi surface glycoproteins implicated in host cell attachment and invasion, showed that sequences of T. cruzi Tcbat grouped with those of T. cruzi genotype TcI. Our analysis indicates that different members of the T. cruzi clade, with different vertebrate hosts, vectors and pathogenicity, share the extensive expansion and sequence diversification of the TS gene family. Altogether, our results are congruent with the evolutionary history of the T. cruzi clade and represent a contribution to the understanding of the molecular evolution and role of TS proteins in trypanosomes. © 2015 Elsevier B.V.. Source


Loro M.,Simon Bolivar University of Venezuela | Valero-Jimenez C.A.,University of Zulia | Nozawa S.,Central University of Venezuela | Marquez L.M.,Simon Bolivar University of Venezuela | Marquez L.M.,Fundacion Institute Estudios Avanzados
Journal of Arid Environments | Year: 2012

Fungal endophytes grow asymptomatically within the tissues of all vascular plants and some are known to provide their host plants with tolerance to different types of environmental stress. The diversity and incidence of fungal endophytes has been negatively correlated with latitude. However, fungal endophyte communities from arid and semiarid environments do not follow this pattern, arguably due to their extreme conditions. In this study, fungal endophytes were cultured from dominant grasses and sedges growing at three different environments in the neotropical semiarid region of Northwest Venezuela. Operational Taxonomic Units were clearly differentiated using phylogenetic analysis of the ITSrDNA region. The results indicated that the incidence and diversity of fungal endophytes in these samples were comparable with those in other tropical plant communities and those in semiarid temperate grasslands. The most common OTUs within the grasses and sedges were related to Cochliobolus sp. and Phoma sp. (Order Pleosporales). This supports the notion that dark septate fungal endophytes dominate semiarid grasslands worldwide. © 2012 Elsevier Ltd. Source


Nino C.H.,National University of Colombia | Forero-Baena N.,National University of Colombia | Contreras L.E.,National University of Colombia | Sanchez-Lancheros D.,National University of Colombia | And 2 more authors.
Memorias do Instituto Oswaldo Cruz | Year: 2015

The intracellular parasite Trypanosoma cruzi is the aetiological agent of Chagas disease, a public health concern with an increasing incidence rate. This increase is due, among other reasons, to the parasite’s drug resistance mechanisms, which require nicotinamide adenine dinucleotide (NAD+). Furthermore, this molecule is involved in metabolic and intracellular signalling processes necessary for the survival of T. cruzi throughout its life cycle. NAD+ biosynthesis is performed by de novo and salvage pathways, which converge on the step that is catalysed by the enzyme nicotinamide mononucleotide adenylyltransferase (NMNAT) (enzyme commission number: 2.7.7.1). The identification of the NMNAT of T. cruzi is important for the development of future therapeutic strategies to treat Chagas disease. In this study, a hypothetical open reading frame (ORF) for NMNAT was identified in the genome of T. cruzi. The corresponding putative protein was analysed by simulating structural models. The ORF was amplified from genomic DNA by polymerase chain reaction and was further used for the construction of a corresponding recombinant expression vector. The expressed recombinant protein was partially purified and its activity was evaluated using enzymatic assays. These results comprise the first identification of an NMNAT in T. cruzi using bioinformatics and experimental tools and hence represent the first step to understanding NAD+ metabolism in these parasites. © 2015, Fundacao Oswaldo Cruz. All rights reserved. Source


Velasco-Ramirez A.P.,University of Guadalajara | Torres-Moran M.I.,University of Guadalajara | Molina-Moret S.,Fundacion Institute Estudios Avanzados | de Jesus Sanchez-Gonzalez J.,University of Guadalajara | Santacruz-Ruvalcaba F.,University of Guadalajara
Electronic Journal of Biotechnology | Year: 2014

Background: At present, species known as camote de cerro (Dioscorea spp.) are found only in the wilderness in Mexico, but their populations are extremely depleted because they are indiscriminately collected, it is urgent to evaluate the conservation status of these plants in order to design conservation genetics programs. In this study, genetic diversity parameters along with cluster analysis based on Jaccard's coefficient were estimated 16 with the objective to assess the efficiency of RandomAmplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeat (ISSR), Amplified Fragment Length Polymorphism (AFLP) and Inverse Sequence Tagged Repeat (ISTR) molecular DNA markers in the Dioscorea genus. Results: The polymorphic information contents were quite similar for all markers (≈0.48). Genetic variation of Dioscorea spp., in terms of average heterozygosity was lower with ISTR (0.36), and higher when other markers were used (RAPD = 0.43; ISSR = 0.45 and AFLP = 0.47). Conclusion: This indicates an important level of genetic differences despite the fact that the plant is asexually propagated. Based on the diversity statistics, any marker tested in present work can be recommended for use in large-scale genetic studies of populations. However, the low correlations among different molecular marker systems show the importance of the complementarity of the information that is generated by different markers for genetic studies involving estimation of polymorphism and relationships. © 2014 Pontificia Universidad Católica de Valparaíso. Production and hosting by Elsevier B.V. All rights reserved. Source

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