Mott G.A.,Harvard University |
Mott G.A.,University of Toronto |
Costales J.A.,Harvard University |
Costales J.A.,Pontificia University Cato lica del Ecuador |
Burleigh B.A.,Harvard University
PLoS ONE | Year: 2011
The protozoan parasite Trypanosoma cruzi, which causes human Chagas' disease, exerts a variety of effects on host extracellular matrix (ECM) including proteolytic degradation of collagens and dampening of ECM gene expression. Exposure of primary human dermal fibroblasts to live infective T. cruzi trypomastigotes or their shed/secreted products results in a rapid down-regulation of the fibrogenic genes collagenIα1, fibronectin and connective tissue growth factor (CTGF/CCN2). Here we demonstrate the ability of a secreted/released T. cruzi factor to antagonize ctgf/ccn2 expression in dermal fibroblasts in response to TGF-ß, lysophosphatidic acid or serum, where agonist-induced phosphorylation of the mitogen-activated protein (MAP) kinases Erk1/2, p38 and JNK was also inhibited. Global analysis of gene expression in dermal fibroblasts identified a discrete subset of TGF-ß-inducible genes involved in cell proliferation, wound repair, and immune regulation that are inhibited by T. cruzi secreted/released factors, where the genes exhibiting the highest sensitivity to T. cruzi are known to be regulated by MAP kinase-activated transcription factors. Consistent with this observation, the Ets-family transcription factor binding site in the proximal promoter region of the ctgf/ccn2 gene (-91 bp to -84 bp) was shown to be required for T. cruzi-mediated down-regulation of ctgf/ccn2 reporter expression. The cumulative data suggest a model in which T. cruzi-derived molecules secreted/released early in the infective process dampen MAP kinase signaling and the activation of transcription factors that regulate expression of fibroblast genes involved in wound repair and tissue remodelling, including ctgf/ccn2. These findings have broader implications for local modulation of ECM synthesis/remodelling by T. cruzi during the early establishment of infection in the mammalian host and highlight the potential for pathogen-derived molecules to be exploited as tools to modulate the fibrogenic response. © 2011 Mott et al.
Espinosa S.,University of Florida |
Espinosa S.,Pontificia University Cato lica del Ecuador |
Branch L.C.,University of Florida |
Cueva R.,Wildlife Conservation Society
PLoS ONE | Year: 2014
Protected areas are essential for conservation of wildlife populations. However, in the tropics there are two important factors that may interact to threaten this objective: 1) road development associated with large-scale resource extraction near or within protected areas; and 2) historical occupancy by traditional or indigenous groups that depend on wildlife for their survival. To manage wildlife populations in the tropics, it is critical to understand the effects of roads on the spatial extent of hunting and how wildlife is used. A geographical analysis can help us answer questions such as: How do roads affect spatial extent of hunting? How does market vicinity relate to local consumption and trade of bushmeat? How does vicinity to markets influence choice of game? A geographical analysis also can help evaluate the consequences of increased accessibility in landscapes that function as source-sink systems. We applied spatial analyses to evaluate the effects of increased landscape and market accessibility by road development on spatial extent of harvested areas and wildlife use by indigenous hunters. Our study was conducted in Yasuní Biosphere Reserve, Ecuador, which is impacted by road development for oil extraction, and inhabited by the Waorani indigenous group. Hunting activities were self-reported for 12-14 months and each kill was georeferenced. Presence of roads was associated with a two-fold increase of the extraction area. Rates of bushmeat extraction and trade were higher closer to markets than further away. Hunters located closer to markets concentrated their effort on large-bodied species. Our results clearly demonstrate that placing roads within protected areas can seriously reduce their capacity to sustain wildlife populations and potentially threaten livelihoods of indigenous groups who depend on these resources for their survival. Our results critically inform current policy debates regarding resource extraction and road building near or within protected areas.
Rincon S.,El Bosque University |
Reyes J.,El Bosque University |
Reyes J.,University of Houston |
Carvajal L.P.,El Bosque University |
And 11 more authors.
Journal of Antimicrobial Chemotherapy | Year: 2013
Objectives: Clinical failures with cefazolin have been described in high-inoculum infections caused by methicillinsusceptible Staphylococcus aureus (MSSA) producing type A b-lactamase. We investigated the prevalence of the cefazolin inoculum effect (InE) in MSSA from South American hospitals, since cefazolin is used routinely against MSSA due to concerns about the in vivo efficacy of isoxazolyl penicillins. Methods: MSSA isolates were recovered from bloodstream (n=296) and osteomyelitis (n=68) infections in two different multicentre surveillance studies performed in 2001-02 and 2006-08 in South American hospitals. We determined standard-inoculum (105cfu/mL) and high-inoculum (107 cfu/mL) cefazolin MICs. PFGEwas performed on all isolates that exhibited a cefazolin InE. Multilocus sequence typing (MLST) and sequencing of part of blaZwere performed on representative isolates. Results: The overall prevalence of the cefazolin InE was 36% (131 isolates). A high proportion (50%) of MSSA isolates recovered fromosteomyelitis infections exhibited the InE, whereas itwas observed in33%of MSSArecovered from blood streaminfections. Interestingly, Ecuador had the highest prevalence of the InE (45%). Strikingly,63%of MSSA isolates recovered fromosteomyelitis infections in Colombia exhibited the InE. MLSTrevealed that MSSA isolates exhibiting the InE belonged to diverse genetic backgrounds, including ST5, ST8, ST30 and ST45, which correlated with the prevalent methicillin-resistant S. aureus clones circulating in South America. Types A (66%) and C (31%) were the most prevalent b-lactamases. Conclusions: Our results showa high prevalence of the cefazolin InE associated with type A b-lactamase in MSSA isolates from Colombia and Ecuador, suggesting that treatment of deep-seated infections with cefazolin in those countries may be compromised. © The Author 2013. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.
James S.A.,UK Institute of Food Research |
Barriga E.J.C.,Pontificia University Cato lica del Ecuador |
Barahona P.P.,Pontificia University Cato lica del Ecuador |
Cross K.,UK Institute of Food Research |
And 2 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2013
In the course of an on-going study aimed at cataloguing the natural yeast biodiversity found in Ecuador, two strains (CLQCA 13-025 and CLQCA 20-004T) were isolated from samples of cow manure and rotten wood collected in two separate provinces of the country (Orellana and Bolívar). These strains were found to represent a novel yeast species based on the sequences of their D1/D2 domain of the large-subunit (LSU) rRNA gene and their physiological characteristics. Phylogenetic analysis based on LSU D1/D2 sequences revealed this novel species to belong to the Metschnikowia clade and to be most closely related to Candida suratensis, a species recently discovered in a mangrove forest in Thailand. The species name of Candida ecuadorensis sp. nov. is proposed to accommodate these strains, with strain CLQCA 20-004T (=CBS 12653T=NCYC 3782T) designated as the type strain. © 2013 IUMS.