Browsing by Author "Andrade, S."

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    Decoupling of biotic and abiotic patterns in a coastal area affected by chronic metal micronutrients disturbances
    (2021) Glasner, B.; Henriquez-Castillo, C.; Alfaro, F. D.; Trefault, N.; Andrade, S.; De la Iglesia, R.
    Coastal systems are highly productive areas for primary productivity and ecosystem services and host a large number of human activities. Since industrialization, metal micronutrients in these regions have increased. Phytoplankton use metals as micronutrients in metabolic processes, but in excess, had deleterious effects. In coastal systems, picoeukaryotes represent a diverse and abundant group with widespread distribution and fundamental roles in biogeochemical cycling. We combined different approaches to explore picoeukaryotes seasonal variability in a chronically metal polluted coastal area at the south-eastern Pacific Ocean. Through remote and field measurements to monitor environmental conditions and 18S rRNA gene sequencing for taxonomic profiling, we determined metal chronic effect on picoeukaryote community?s structure. Our results revealed a stable richness and a variable distribution of the relative abundance, despite the physicochemical seasonal variations. These results suggest that chronic metal contamination influences temporal heterogeneity of picoeukaryote communities, with a decoupling between abiotic and biotic patterns.
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    Novel polymerase chain reaction primers for the specific detection of bacterial copper P-type ATPases gene sequences in environmental isolates and metagenomic DNA
    (WILEY, 2010) De la Iglesia, R.; Valenzuela Heredia, D.; Pavissich, J. P.; Freyhoffer, S.; Andrade, S.; Correa, J. A.; Gonzalez, B.
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    Physiological plasticity of Dictyota kunthii (Phaeophyceae) to copper excess
    (2014) Sordet, C.; Contreras-Porcia, L.; Lovazzano, C.; Goulitquer, S.; Andrade, S.; Potin, P.; Correa, J. A.
    The brown alga Dictyota kunthii is one of the dominant species in the coastal areas of northern Chile affected by copper enrichment due to accumulated mining wastes. To assess its physiological plasticity in handling copper-mediated oxidative stress, 4-days copper exposure (ca. 100 mu g/L) experiments were conducted with individuals from a copper impacted area and compared with the responses of plants from a non-impacted site. Several biochemical parameters were then evaluated and compared between populations. Results showed that individuals from the copper-impacted population normally displayed higher levels of copper content and antioxidant enzymes activity (catalase (CAT), ascorbate peroxidase (AP), dehydroascorbate reductase (DHAR), glutathione peroxidase (GP) and peroxiredoxins (PRX)). After copper exposure, antioxidant enzyme activity increased significantly in plants from the two selected sites. In addition, we found that copper-mediated oxidative stress was associated with a reduction of glutathione reductase (GR) activity. Moreover, metabolic profiling of extracellular metabolites from both populations showed a significant change after plants were exposed to copper excess in comparison with controls, strongly suggesting a copper-induced release of metabolites. The copper-binding capacity of those exudates was determined by anodic stripping voltammetry (ASV) and revealed an increased ligand capacity of the medium with plants exposed to copper excess. Results indicated that D. kunthii, regardless their origin, counteracts copper excess by various mechanisms, including metal accumulation, activation of CAT, AP, DHAR, GP and PRX, and an induced release of Cu binding compounds. Thus, plasticity in copper tolerance in D. kunthii seems constitutive, and the occurrence of a copper-tolerant ecotype seems unlikely. (C) 2014 Elsevier B.V. All rights reserved.