DNA damage and metal accumulation in four tissues of feral Octopus vulgaris from two coastal areas in Portugal,
Raimundo, Joana, Costa Pedro M., Vale Carlos, Costa Maria Helena, and Moura Isabel
, Ecotoxicology and Environmental Safety, Oct, Volume 73, Number 7, p.1543-1547, (2010)
AbstractThe alkaline comet assay has been employed for the first time to estimate the basal DNA damage in the digestive gland, gills, kidney and gonads of Octopus vulgaris. Octopuses were captured in two coastal areas adjacent to the cities of Matosinhos (N) and Olhao (S), Portugal. The area of Matosinhos is influenced by discharges of the Douro River, city of Porto, industries and intensive agriculture, while Olhao is an important fisheries port. Previous works point to contrasting metal availability in the two coastal areas. Among the analysed tissues digestive gland presented the highest levels of Zn, Cu, Cd and Pb. Tissues of specimens from Matosinhos exhibited high levels of Cd and from Olhao enhanced Pb concentrations. The DNA damages in digestive gland, gills and kidney were more accentuated in specimens from Matosinhos than from Olhao, suggesting a stronger effect of contaminants. Elevated strand breakages were registered in digestive gland, recognised for its ability to store and detoxify accumulated metals. The DNA damages in kidney, gills and gonads were lower, reflecting reduced metal accumulation or efficient detoxification. The broad variability of damages in the three tissues may also mirror tissue function, specific defences to genotoxicants and cell-cycle turnover. (C) 2010 Elsevier Inc. All rights reserved.
Association of Zn, Cu, Cd and Pb with protein fractions and sub-cellular partitioning in the digestive gland of Octopus vulgaris living in habitats with different metal levels,
Raimundo, J., Vale C., Duarte R., and Moura I.
, Chemosphere, Nov, Volume 81, Number 10, p.1314-1319, (2010)
AbstractZinc Cu Cd and Pb concentrations were determined in protein fractions of digestive gland and in the whole digestive gland of Octopus vulgaris collected from two areas of the Portuguese coast Approximately 95% of Zn 99% of Cu 85-96% of Cd and 77-86% of Pb were stored in the cytosol suggesting the predominance of cytosolic proteins in the trapping these elements Gel filtration chromatography evidenced the presence of two major groups of proteins with high molecular weight (HMW 144 000-130 000 Da) and low molecular weight (LMW 11 000-6000 Da) The following metal-protein associations were found Zn was distributed between HMW and LMW Cu and Cd in LMW proteins with a minor association with HMW and Pb in HMW proteins The strong positive correlations between Cd Zn and Cu and LMW proteins point to the presence of metalloproteins with high affinity to these elements A shift was registered between the maximum of the ratio 254 280 nm and metal concentrations in the chromatographic profiles This shift may result from metallothioneins having a small participation in the metal binding or protein purification was insufficient and various LMW proteins may be interfering (C) 2010 Elsevier Ltd All rights reserved
An efficient non-mediated amperometric biosensor for nitrite determination,
Silveira, C. M., Gomes S. P., Araujo A. N., Montenegro M. C., Todorovic S., Viana A. S., Silva R. J., Moura J. J., and Almeida M. G.
, Biosens Bioelectron, May 15, Volume 25, Number 9, p.2026-32, (2010)
AbstractIn this paper we propose the construction of a new non-mediated electrochemical biosensor for nitrite determination in complex samples. The device is based on the stable and selective cytochrome c nitrite reductase (ccNiR) from Desulfovibrio desulfuricans, which has both high turnover and heterogeneous electron transfer rates. In opposition to previous efforts making use of several redox mediators, in this work we exploited the capacity of ccNiR to display a direct electrochemical response when interacting with pyrolytic graphite (PG) surfaces. To enable the analytical application of such bioelectrode the protein was successfully incorporated within a porous silica glass made by the sol-gel process. In the presence of nitrite, the ccNiR/sol-gel/PG electrode promptly displays catalytic currents indicating that the entrapped ccNiR molecules are reduced via direct electron transfer. This result is noteworthy since the protein molecules are caged inside a non-conductive silica network, in the absence of any mediator species or electron relay. At optimal conditions, the minimum detectable concentration is 120 nM. The biosensor sensitivity is 430 mA M(-1) cm(-2) within a linear range of 0.25-50 microM, keeping a stable response up to two weeks. The analysis of nitrites in freshwaters using the method of standard addition was highly accurated.
An NMR structural study of nickel-substituted rubredoxin,
Goodfellow, B. J., Duarte I. C., Macedo A. L., Volkman B. F., Nunes S. G., Moura I., Markley J. L., and Moura J. J.
, J Biol Inorg Chem, Mar, Volume 15, Number 3, p.409-20, (2010)
AbstractThe Ni(II) and Zn(II) derivatives of Desulfovibrio vulgaris rubredoxin (DvRd) have been studied by NMR spectroscopy to probe the structure at the metal centre. The beta CH(2) proton pairs from the cysteines that bind the Ni(II) atom have been identified using 1D nuclear Overhauser enhancement (NOE) difference spectra and sequence specifically assigned via NOE correlations to neighbouring protons and by comparison with the published X-ray crystal structure of a Ni(II) derivative of Clostridium pasteurianum rubredoxin. The solution structures of DvRd(Zn) and DvRd(Ni) have been determined and the paramagnetic form refined using pseudocontact shifts. The determination of the magnetic susceptibility anisotropy tensor allowed the contact and pseudocontact contributions to the observed chemical shifts to be obtained. Analysis of the pseudocontact and contact chemical shifts of the cysteine H beta protons and backbone protons close to the metal centre allowed conclusions to be drawn as to the geometry and hydrogen-bonding pattern at the metal binding site. The importance of NH-S hydrogen bonds at the metal centre for the delocalization of electron spin density is confirmed for rubredoxins and can be extrapolated to metal centres in Cu proteins: amicyanin, plastocyanin, stellacyanin, azurin and pseudoazurin.
Relations between mercury, methyl-mercury and selenium in tissues of Octopus vulgaris from the Portuguese Coast,
Raimundo, Joana, Vale Carlos, Canario Joao, Branco Vasco, and Moura Isabel
, Environmental Pollution, Jun, Volume 158, Number 6, p.2094-2100, (2010)
AbstractMercury, methyl-mercury (MeHg) and selenium were determined in digestive gland and mantle of Octopus vulgaris, from three areas of the Portuguese coast. To our knowledge these are the first data on MeHg in cephalopods. Concentrations were higher in the digestive gland and percentage of MeHg in mantle. Enhanced Hg and MeHg levels were obtained in digestive gland of specimens from Olhao (3.1-7.4 and 2.0-5.0 mu g g(-1) respectively). Differences between areas may be partially related to Hg availability. Relationships between concentrations in mantle and digestive gland pointed to proportional increases of Hg and MeHg in tissues of specimens from Matosinhos and Cascais, but relatively constant values in mantle of individuals from Olhao (higher contamination). Se:Hg molar ratio in digestive gland was 32 and 30 in octopus from Matosinhos and Cascais, respectively, and 5.4 from Olhao. The proximity to the unit suggests demethylation as response to elevated MeHg levels in digestive gland. (C) 2010 Elsevier Ltd. All rights reserved.
Metallothioneins and trace elements in digestive gland, gills, kidney and gonads of Octopus vulgaris,
Raimundo, J., Costa P. M., Vale C., Costa M. H., and Moura I.
, Comparative Biochemistry and Physiology C-Toxicology & Pharmacology, Aug, Volume 152, Number 2, p.139-146, (2010)
AbstractMetallothionein-like proteins (MT) and V, Cr, Co, Ni, Zn, Cu, As and Cd were determined in digestive gland, gills, kidney and gonads of Octopus vulgaris, from the Portuguese coast. To our knowledge these are the first data on MT in octopus. High concentrations (mu g g(-1), dry mass) of Zn (48050) and Cd (555) were found in digestive gland, and MT reached levels one order of magnitude above the ones registered in wild bivalves. Significantly higher levels of MT in digestive gland and gills of specimens from A and B were in line with elevated Cd concentrations. Principal component analyses (PCA) point to MT-Cd and MT-Cr associations in digestive gland and gills. Despite the high levels of Zn in specimens from B, association with Zn was not obtained. Due to the affinity of MT to various elements, it should not be excluded the possibility of Cd replacing Zn in Zn-MT. Kidney presented higher levels of Cd, Co, Ni and As than gills and gonads, and in the case of As surpassing the levels in digestive gland, but PCA showed no relation with MT. Likewise the MT levels in gonads had no correspondence to the metal concentration variation. (C) 2010 Elsevier Inc. All rights reserved.