Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

The science of the total environment

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

Molecular biomarkers of oxidative stress in aquatic organisms in relation to toxic environmental pollutants.

The use of biomarkers to assess the impact of pollution in coastal environments of the Iberian Peninsula: a practical approach

Mechanisms of metal uptake. The interactions between living organisms and metals in intertidal and subtidal sediments. Microorganisms and the biogeochemical cycling of metals in aquatic environments. Metal accumulation and impacts in phytoplankton. Mercury in aquatic ecosystems. Arsnic metabolism in aquatic ecosystems. Determinants of trace metal concentrations in marine organisms. Metal handling strategies in molluscs. Phylogeny of trace metal accumulation and toxicity in fish. Influence of ecological factors on accumulation of metal mixtures. Metals and marine food chains. Metal accumulation and detoxification in humans.

Metal metabolism in aquatic environments

Microplastics effects in Scrobicularia plana.

The concentration and distribution of metals in molluscan tissues, as in any other organism, is highly dependent on the biochemical processes of metal metabolism occurring within cells. Many of these processes and associated metal-binding systems are common to a broad range of phyla, reflecting their evolutionary success in regulating the essential elements (e.g. Cu, Zn, Fe, Mn, Co) for physiological, biochemical and morphological purposes. The involvement of metallothionein (MT) in buffering intracellular metal ions is one of the best examples of such a ubiquitous metal sequestration system. Proteins of a metallothionein-like nature are represented in many branches of the phylogenetic tree, from microorganisms to humans, and consequently are regarded as a central constituent of metal metabolism. Other sequestration mechanisms are relatively unique to individual taxonomie groups so that even within a single phylum, exemplified here by molluscs, there may be a large diversity in the nature and expression of metal metabolism, according to metal requirements. The result is manifested by a wide range of behaviour in terms of uptake, detoxification and storage — the major components of metal bioaccumulation.

Metal handling strategies in molluscs

CuO NPs are widely used in various industrial and commercial applications. However, little is known about their potential toxicity or fate in the environment. In this study the effects of copper nanoparticles were investigated in the gills of mussels Mytilus galloprovincialis, comparative to Cu(2+). Mussels were exposed to 10 μg Cu·L(-1) of CuO NPs and Cu(2+) for 15 days, and biomarkers of oxidative stress, metal exposure and neurotoxicity evaluated. Results show that mussels accumulated copper in gills and responded differently to CuO NPs and Cu(2+), suggesting distinct modes of action. CuO NPs induced oxidative stress in mussels by overwhelming gills antioxidant defense system, while for Cu(2+) enzymatic activities remained unchanged or increased. CuO NPs and Cu(2+) originated lipid peroxidation in mussels despite different antioxidant efficiency. Moreover, an induction of MT was detected throughout the exposure in mussels exposed to nano and ionic Cu, more evident in CuO NPs exposure. Neurotoxic effects reflected as AChE inhibition were only detected at the end of the exposure period for both forms of copper. In overall, these findings show that filter-feeding organisms are significant targets for nanoparticle exposure and need to be included when evaluating the overall toxicological impact of nanoparticles in the aquatic environment.

Maria João Bebianno

Papers

The use of biomarkers to assess the impact of pollution in coastal environments of the Iberian Peninsula: a practical approach

Metal metabolism in aquatic environments

Microplastics effects in Scrobicularia plana.

Metal handling strategies in molluscs

Effects of copper nanoparticles exposure in the mussel Mytilus galloprovincialis.