Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Maria Elena Giordano is active.

Publication


Featured researches published by Maria Elena Giordano.


BioMed Research International | 2013

Acetylcholinesterase as a Biomarker in Environmental and Occupational Medicine: New Insights and Future Perspectives

Maria Giulia Lionetto; Roberto Caricato; A. Calisi; Maria Elena Giordano; Trifone Schettino

Acetylcholinesterase (AChE) is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring.


Cellular Physiology and Biochemistry | 2002

Roles of the Cytoskeleton and of Protein Phosphorylation Events in the Osmotic Stress Response in EEL Intestinal Epithelium

Maria Giulia Lionetto; Stine F. Pedersen; Else K. Hoffmann; Maria Elena Giordano; Trifone Schettino

The eel intestinal epithelium responds to an acute hypertonic challenge by a biphasic increase of the rate of Cl- absorption (measured as short circuit current, Isc, and creating a negative transepithelial potential, Vte, at the basolateral side of the epithelium). While the first, transient phase is bumetanide-insensitive, the second, sustained phase is bumetanide-sensitive, reflecting activation of the apically located Na+-K+-2Cl- (NKCC) cotransporter, which correlates with the cellular RVI response.Here, we investigated the involvement of the cytoskeleton and of serine/threonine phosphorylation events in the osmotic stress-induced ion transport in the eel intestinal epithelium, focusing on the sustained RVI phase, as well as on the previously uncharacterized response to hypotonic stress.The study was carried out using confocal laser scanning microscopy, a quantitative F-actin assay, and transepithelial electrophysiological measurements (Vte and Isc) in Ussing chambers. Hypertonic stress did not detectably alter either net F-actin content or F-actin organization. In contrast, a brief exposure to hypotonic stress decreased the total cellular F-actin content in eel intestinal epithelium by about 15%, detectable morphologically mainly as a decrease in the intensity of the apical brush border F-actin labeling.The bumetanide-sensitive response of Vte and Isc to hypertonicity was potently inhibited by treatment with either cytochalasin, latrunculin A, colchicine, the protein kinase C (PKC) inhibitor chelerythrine, the myosin light chain kinase (MLCK) inhibitor ML-7, or the serine/threonine protein phosphatase inhibitor Calyculin A, but was unaffected by the PKA inhibitor H-89. The electrophysiological response of the epithelium to hypotonic stress was characterized by a sustained decrease of Vte and Isc, which was smaller and recovered faster in the presence of either cytochalasin, latrunculin A, or colchicine.It is concluded that in eel intestinal epithelium, the changes in ion transport in response to both hyper- and hypotonic stress require the integrity of both F-actin and microtubules. In addition, the shrinkage-induced activation of NKCC appears to require the activity of both PKC and MLCK. It is suggested that NKCC regulation by hypertonic stress involves an interaction between the cytoskeleton and protein phosphorylation events.


International Journal of Environmental Research and Public Health | 2012

Carbonic Anhydrase as Pollution Biomarker: An Ancient Enzyme with a New Use

Maria Giulia Lionetto; Roberto Caricato; Maria Elena Giordano; Elisa Erroi; Trifone Schettino

The measurement of cellular and sub-cellular responses to chemical contaminants (referred to as biomarkers) in living organisms represents a recent tool in environmental monitoring. The review focuses on carbonic anhydrase, a ubiquitous metalloenzyme which plays key roles in a wide variety of physiological processes involving CO2 and HCO3−. In the last decade a number of studies have demonstrated the sensitivity of this enzyme to pollutants such as heavy metals and organic chemicals in both humans and wildlife. The review analyses these studies and discusses the potentiality of this enzyme as novel biomarker in environmental monitoring and assessment.


Chemistry and Ecology | 2004

Biomarker application for the study of chemical contamination risk on marine organisms in the taranto marine coastal area

Maria Giulia Lionetto; Roberto Caricato; Maria Elena Giordano; Trifone Schettino

This work represents a pilot study for monitoring the potential toxicological risk of commercial relevant marine resources along the South coast of Italy by using biomarkers as complementary tool to chemical analysis. The attention was focused on the industrialized area of Salento peninsula, such as Taranto, that, in spite of the presence of the big industry (oil, metal industry), sustains activities related to the sea resources, such as fishery and mussel-culture. The study was carried out in fish, such as Mullus barbatus and Trachurus mediterraneus, two important fish species for the fishery in this area, and in mussels (Mytilus galloprovincialis). As control area S. Maria di Leuca, area of naturalistic interest, was chosen. In fish, liver metallothionein levels (specific index of exposure to heavy metals such as Hg, Cd, Cu and Zn) and brain and muscular acetylcholinesterase (AChE) activity (specific index of exposure to organophosphate and carbamate pesticides) were measured. None of the two fish species showed significant differences in AChE activity and in pesticide trace level between the anthropogenic impact exposed site and the control group. On the other hand, metallothionein hepatic levels in M. barbatus were significantly increased in the organisms coming from Taranto with respect to the organisms coming from the control site, but chemical analysis, routinely performed on edible muscle for the evaluation of chemical quality of fish products, did not reveal high heavy metal concentration in the edible muscle of fish from Taranto. Mussels exposed for one month in the Mar Piccolo of Taranto, an important mussel farming area, showed increase in the level of catalase activity, an oxidative stress index, increase in the levels of metallothioneins and inhibition of AChE activity. The need to integrate chemical analysis with the study of biological responses to pollutants (biomarkers) in marine organisms is discussed for a better comprehension of the impact of chemical contaminants on the sea and its resources.


Environmental Toxicology and Chemistry | 2007

Morphometric alterations in Mytilus galloprovincialis granulocytes: A new biomarker

A. Calisi; Maria Giulia Lionetto; Roberto Caricato; Maria Elena Giordano; Trifone Schettino

Bivalve molluscs, particularly marine mussels, are used widely as sentinel organisms in environmental quality monitoring and assessment. Biochemical and cellular responses to pollutant exposure (i.e., biomarkers) increasingly are investigated in mussel tissues and their measurements largely used in marine environmental monitoring. The aim of the present study was to investigate possible pollutant-induced morphometric alterations in Mytilus galloprovincialis granulocytes in view of future applications as a sensitive, simple, and quick biomarker for monitoring and assessment applications. Granulocyte morphometric alterations were determined by image analysis on Diff-Quick® stained cells. For the first time, the rapid alcohol-fixed Diff-Quick stain protocol, utilized in clinical and veterinary applications for immediate interpretation of histological samples, was shown to be suitable for rapid cytological staining of M. galloprovincialis haemocytes. The present study was carried out in standardized laboratory conditions and further validated in field conditions. Results show consistent pollutant-induced enlargement of mussel granulocytes. This was verified by standardized biomarkers such as metallothionein concentrations in the digestive gland or lysosomal membrane stability in laboratory and field exposures. Results further suggest that the observed morphometric alterations can be used as a biomarker of chemical stress. Because no single biomarker generally is adequate for describing the complexity of effects induced by environmental pollutants on the organisms, we propose that morphometric alterations of granulocytes should be used in a biomarker battery in marine environmental monitoring programs such as Mussel Watch.


Chemistry and Ecology | 2006

Potential application of carbonic anhydrase activity in bioassay and biomarker studies

Maria Giulia Lionetto; Roberto Caricato; Elisa Erroi; Maria Elena Giordano; Trifone Schettino

Carbonic anhydrase (CA) (EC 4.2.1.1), a ubiquitous enzyme in bacteria, plant, and animal kingdoms, catalyses the reversible hydration of CO2 to produce H+ and using zinc as cofactor. CA plays a fundamental role in a number of physiological processes, such as respiration, ionic transport, acid–base regulation, and calcification. The aim of the present work was to investigate the sensitivity of this enzyme to heavy metals with a view to possible future applications of CA activity inhibition measurement in biomonitoring as either an in vitro bioassay or a biomarker. CA activity was determined by modifying a previously described electrometric method: briefly, CA activity units were calculated from the rate of H+ production in the reaction mixture (where CO2 was present as a substrate) against a blank containing the specific CA inhibitor acetazolamide. As regards the possible application as an in vitro bioassay, the sensitivity to heavy metals (cadmium, mercury, and copper) of the commercially available purified carbonic anhydrase (isozyme II) from bovine erythrocyte was tested in vitro. In our experimental set-up, bovine CA activity was significantly inhibited by micromolar concentrations of heavy metals, showing a dose–response behaviour. As regards the possible application as biomarkers, CA was investigated in the filter-feeding Mytilus galloprovincialis, widely used in pollution-monitoring programmes as a sentinel organism. Following in vitro and in vivo exposure to 1.785 μM cadmium chloride as a reference toxicant, mantle CA activity was significant inhibited. In conclusion, the sensitivity to chemical pollutants and low cost and simplicity of the assay method make CA activity measurement suitable for in vitro bioassay of the toxicity of environmental samples and for field biomarker applications in the sentinel organism M. galloprovincialis.


International Journal of Molecular Sciences | 2016

The Complex Relationship between Metals and Carbonic Anhydrase: New Insights and Perspectives

Maria Giulia Lionetto; Roberto Caricato; Maria Elena Giordano; Trifone Schettino

Carbonic anhydrase is a ubiquitous metalloenzyme, which catalyzes the reversible hydration of CO2 to HCO3− and H+. Metals play a key role in the bioactivity of this metalloenzyme, although their relationships with CA have not been completely clarified to date. The aim of this review is to explore the complexity and multi-aspect nature of these relationships, since metals can be cofactors of CA, but also inhibitors of CA activity and modulators of CA expression. Moreover, this work analyzes new insights and perspectives that allow translating new advances in basic science on the interaction between CA and metals to applications in several fields of research, ranging from biotechnology to environmental sciences.


Cellular Physiology and Biochemistry | 2008

Molecular and Functional Expression of High Conductance Ca 2+ Activated K + Channels in the Eel Intestinal Epithelium

Maria Giulia Lionetto; Antonia Rizzello; Maria Elena Giordano; Michele Maffia; Francesco De Nuccio; Giuseppe Nicolardi; Else K. Hoffmann; Trifone Schettino

Several types of K+ channels have been identified in epithelial cells. Among them high conductance Ca2+-activated K+ channels (BK channels) are of relevant importance for their involvement in regulatory volume decrease (RVD) response following hypotonic stress. The aim of the present work was to investigate the functional and molecular expression of BK in the eel intestine, which is a useful experimental model for cell volume regulation research. In the present paper using rat BK channel-specific primer, a RT-PCR signal of 696 pb cDNA was detected in eel intestine, whole nucleotide sequence showed high similarity (83%) to the alpha subunit of BK channel family. BK channel protein expression was verified by immunoblotting and confocal microscopy, while the functional role of BK channels in epithelial ion transport mechanisms and cell volume regulation was examined by electrophysiological and morphometric analysis on the intact tissue. BKCa channels appeared to be localized along all the plasma membrane of the enterocytes; the apical part of the villi showed the most intense immunostaining. These channels were silent in basal condition, but were activated on both membranes (apical and basolateral) by increasing intracellular Ca2+ concentration with the Ca2+ ionophore ionomycin (1µM). BKCa channels were also activated on both membranes by hypotonic swelling of the epithelium and their inhibition by 100 nM iberiotoxin (specific BKCa inhibitor) abolished the Regulatory Volume Decrease (RVD) of the intestinal cells after hypotonic swelling. In conclusion, our results demonstrated the molecular and functional expression of high conductance Ca2+ -activated K+ channels in eel intestine; the physiological role of these channels is mainly related to the RVD response of the epithelial cells following hypotonic swelling.


Cellular Physiology and Biochemistry | 2010

Role of BK Channels in the Apoptotic Volume Decrease in Native Eel Intestinal Cells

Maria Giulia Lionetto; Maria Elena Giordano; A. Calisi; Roberto Caricato; Else K. Hoffmann; Trifone Schettino

High conductance Ca+-activated K+ channels (BK channels) have previously been demonstrated in the eel intestine. They are specifically activated following a hypotonic stress and sustain Regulatory Volume Decrease (RVD). The aim of the present work was to address the possible role of these channels in the Apoptotic Volume Decrease (AVD) of isolated eel enterocytes, and the possible interaction between BK channels and the progression of apoptosis. The detection of apoptosis was performed by confocal microscopy and annexin V and propidium iodide labelling; cell volume changes were monitored by video imaging. Within a few hours after isolation, enterocytes underwent anoikis (apoptosis induced by detachment from the extracellular matrix). They showed an early normotonic volume decrease (AVD) preceding the appearance of annexin V positivity. AVD occurred in correspondence with an increase in the [Ca2+]i, measured with Fura-2. When the cells were resuspended in high K+ solution or treated with iberiotoxin, AVD was completely abolished. In addition, treatment with high K+ or iberiotoxin significantly inhibited apoptosis progression. It was demonstrated for the first time in native enterocytes that BK channels, which are involved in RVD in these cells, plays also a crucial role in the AVD process and in the progression of apoptosis.


International Journal of Environmental Analytical Chemistry | 2005

Carbonic anhydrase based environmental bioassay

Maria Giulia Lionetto; Roberto Caricato; Elisa Erroi; Maria Elena Giordano; Trifone Schettino

Carbonic anhydrase (CA) is a metalloenzyme catalysing the reversible idratation of CO2 in H+ and . It is an ubiquitous enzyme in bacteria, plant and animal kingdoms, playing a fundamental role in a number of physiological processes. Previous studies demonstrated the sensitivity of CA activity to dichlorodiphenyl-dichloroethane (DDT) exposure in birds and to cadmium exposure in teleosts. The aim of the present work was to develop a new in vitro enzymatic bioassay for detecting toxic chemicals in environmental samples as a cost-effective tool in environmental monitoring. This bioassay uses the commercial available CA isozyme II from bovine erythrocytes whose sensitivity to the main classes of chemical pollutants of importance in water quality research was tested in this work. CA activity was determined by a modification of the electrometric method previously described by Wilbur and Anderson [K.M. Wilbur, G.N. Anderson. J. Biol. Chem., 176, 147 (1948).]: briefly, CA activity units were calculated from the rate of H+ production in the reaction mixture (where CO2 was present as substrate) against a blank containing the specific CA inhibitor acetazolamide. [H+] variation was followed at 0°C in the reaction mixture using a Mettler Delta 350 pH-meter. In our experimental set-up bovine CA activity was significantly inhibited by heavy metals (Cd, Cu and Hg), by the organochlorate compound arochlor and by the carbammate pesticides carbaryl in a dose-dependent manner. CA in vitro bioassay can represent a novel tool for rapid and low cost understanding of the toxicity of environmental samples, for assessing bioavailability of pollutants in environmental matrices and their additive or synergistic biological effects when present in mixtures.

Collaboration


Dive into the Maria Elena Giordano's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

A. Calisi

University of Salento

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge