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Biomedical subjects

G Agell

Publications and source records attributed to G Agell.

5 recordsLinked to original sources
PubMed2005

Response of the Mediterranean sponge Chondrosia reniformis Nardo to copper pollution.

We examined the effects of exposure to copper pollution on the Atlanto-Mediterranean sponge Chondrosia reniformis. We transplanted sponges from an unpolluted control area to a harbour with a moderately high concentration of copper and measured several biological sponge variables. No effect of this habitat was detected on sponge growth, shape, heat-shock protein expression or metal accumulation. However, a decrease in the clearance rate, an increase in the collagen/cell rate (due to a decrease in the cellular components) and a lower survival rate after 4 months of the sponges transplanted to the harbour was observed. We suggest that copper may alter the sponge physiology, by reducing pumping capacity, which may ultimately lead to sponge death. Consequently, copper pollution exerts strong negative effects on this organism.

Animals↗
PubMed2004

Molecular and organism biomarkers of copper pollution in the ascidian Pseudodistoma crucigaster.

We studied the effects of pollution in the colonial ascidian Pseudodistoma crucigaster at organismal and suborganismal levels. Our goal was to find early biomarkers to detect some effect of pollution before changes in community structure or species composition occur. We examined the effect of Cu on the production of heat-shock proteins, defence metabolites, growth rates and presence of resistance forms. We performed a transplant experiment to a Cu polluted harbour and observed negative growth and presence of resistance forms but not depressed production of toxic metabolites or an increase in stress proteins (hsp) in the ascidian. In a laboratory experiment, stress proteins were induced only under half the Cu concentration found in the harbour. We conclude that hsp can be used in this ascidian as an early warning system for sublethal pollution but that the response is inhibited above a threshold of the stressing agent, which may vary among species.

Analysis of Variance↗
PubMed2001

Does stress protein induction by copper modify natural toxicity in sponges?

Crambe crambe is a toxic Mediterranean sponge that inhabits the sublittoral rocky bottoms, including some contaminated habitats. We investigated whether contamination by copper induced stress proteins in C. crambe and whether such stress might alter the production of chemical defenses. The monoclonal antibody used cross-reacted with two heat shock proteins (HSP) of 54 and 72 kDa. Both proteins were induced to a greater or lesser extent by copper contamination. The HSP54 accumulated more than HSP72, which, in contrast, appeared to respond faster and be less persistent. In a field experiment, we found a higher accumulation of HSP54 in individuals naturally inhabiting a copper-contaminated site than in those transplanted to this site four months earlier. In contrast, HSP72 was significantly induced only in the individuals transplanted to the contaminated site. In the laboratory, both proteins were induced by copper at 30 microg/L but inhibited at 100 microg/L. The highest mean values of HSP54 and HSP72 corresponded to the sponges, which showed the lowest mean values of toxicity. Thus, toxicity and production of HSP displayed opposite trends, which seems to indicate a preferential investment in cell repair at the expense of toxic molecules under stress conditions.

Adaptation, Physiological↗