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Metodo per la valutazione enzimatica della tossicità di matrici acquose ambientali
No full textL’invenzione consiste in un metodo innovativo per la misura del grado di tossicità di matrici acquose ambientali in modo rapido, semplice, a basso costo e senza l’utilizzo di organismi vivi. Il principio sul quale esso si basa consiste nella misura in vitro dell’inibizione dell’attività enzimatica di anidrasi carbonica quando questo enzima sia posto a contatto con matrici acquose ambientali (quali acque interstiziali, acque reflue, percolati, ecc) contenenti sostanze tossiche. L’entità della inibizione enzimatica risulta essere proporzionale al grado di tossicità del campione.
Tale metodo è, pertanto, facilmente applicabile ad operazioni di screening di tossicità ambientale
Carbonic anhydrase activity inhibition: application in a new environmental bioassay.
No full textAim: Carbonic anhydrase (CA), a ubiquitous metalloenzyme, catalyses the reversible hydration of CO2 to H+ and HCO3- and plays a fundamental role in a number of physiological processes. Previous studies demonstrated the sensitivity of CA activity to chemical pollutants such as dichlorodiphenyl-dichloroethane (DDT) in birds and cadmium in teleost. The aim of the present work was to investigate the sensitivity of CA isozyme II from bovine erythrocytes to heavy metals, PCBs, and pesticides in view of a possible future applications of CA activity inhibition measurement in biomonitoring field as in vitro bioassay.
Methods: CA activity was determined by a modification of 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 substrate) against a blank containing the specific CA inhibitor acetazolamide. The standardized method is simple, rapid and available to be used for routine measurements.
Results: The enzymatic activity was first exposed to pure compounds showing a significant dose-response inhibition by submicromolar concentrations of heavy metal (Cd, Cu and Hg), and ppb concentrations of arochlor and carbaryl. Then, CA activity was exposed to contaminated environmental real samples (elutriates of harbour sediments) showing a dose-response inhibition to increasing concentrations of the elutriates in the reaction mixture, suggesting a specific response of the enzymatic activity to the toxicity of the samples. Results obtained with CA were in agreement with those obtained in the same samples with Brachionus plicatilis toxicity test and Paracentrotus lividus spermiotoxicity test.
Conclusion: CA activity showed a high sensitivity to the main classes of pollutants relevant for water chemical contamination. Therefore, obtained results suggest the potentiality of CA activity inhibition measurement for application in the screening of general toxicity of environmental samples
Carbonic anhydrase based environmental bioassay
No full textCarbonic anhydrase (CA) is a metalloenzyme catalysing the reversible idratation of CO2 in
Hþ and HCO3 . 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 Hþ production in the reaction mixture (where CO2 was present as
substrate) against a blank containing the specific CA inhibitor acetazolamide. [Hþ] variation
was followed at 0C 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
Potential application of carbonic anhydrase activity in bioassay and biomarker studies
No full textCarbonic 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 HCO−3 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.CAactivitywas 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,
CAwas 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 1.785μM 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
Biomonitoring of water and soil quality: a case study of ecotoxicological methodology application to the assessment of reclaimed agroindustrial wastewaters used for irrigation
No full textThe aim of the work was to evaluate the ecotoxicity
of reclaimed agroindustrial wastewaters used for
irrigation through ecotoxicological bioassays and
biomarkers. The ecotoxicological monitoring was addressed
on both treated wastewaters and irrigated soils.
Wastewater biomonitoring was performed by the acute test
with Daphnia magna, the Microtox test, and a new
in vitro patented method. Soil quality monitoring was
performed by the acute and chronic tests with the earthworm
Eisenia fetida and biomarker analysis, such as
lysosomal membrane stability, general stress biomarker of
chemical pollution, and metallothionein, specific biomarker
of exposure to heavy metals. Overall the integrated
ecotoxicological analysis excluded the presence of
ecotoxicity both in the reclaimed waters resulting from
tertiary treatment and in the irrigated soils. In particular,
the analysis of metallothionein allowed to exclude the
accumulation of bioavailable heavy metals in the soil. This
study suggests the suitability of ecotoxicological methods
for the biomonitoring of water and soil during the
reclaimed wastewaters reuse for irrigation, contributing to
improving the process of agricultural re-use of wastewater
in terms of assessment of the toxicological safety of the
waters for the environment, for traders and consumer
Carbonic anhydrase and chemical pollutants: new applied perspectives
No full textCarbonic anhydrase is an ubiquitous metalloenzyme which catalyses the reversible hydration of CO2 to produce H+ and HCO3-. It plays a key role in a number of physiological processes, including acid-base transport, ion transport, bone resorption, calcification, and metabolic processes.
The present work is addressed 1) to deepen and discuss a recently emerging aspect of the research on this metalloenzyme such as its sensitivity to chemical pollutants, and 2) to highlight how these studies can yield advancement in developing biologically based methodologies useful for environmental monitoring and assessment applications.
Carbonic anhydrase activity showed a high sensitivity to in vitro and in vivo exposure to several heavy metals and xenobiotics in a variety of organisms, including vertebrates and invertebrates, and was demonstrated to be involved in the pollutant induced lysosomal activation in toxicant exposed organisms. These evidenced opened new perspectives for the application of CA as biomarker of pollution exposure, as indicated by the successfully application of CA activity and protein expression measurement in multi-biomarker approaches on bioindicator organisms.
Moreover, the in vitro sensitivity of the enzymatic activity to pollutants triggered the development of a new in vitro patented bioassay (MI2008A008813; PCT/IT2013/000205) which has been successfully utilized for the general toxicity detection of environmental aqueous matrices in biomonitoring programs
METODOLOGIE DI BIOMONITORAGGIO PER LA VALUTAZIONE DELLA QUALITÀ DELLE ACQUE E DEL SUOLO NEL CICLO AGROALIMENTARE
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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