Toxicity testing in environmental monitoring: The role of enzymatic biosensors

Biological toxicity testing is a rapidly expanding field involving numerous bioanalytical techniques. The enzymatic biosensors are valuable screening tools to identify pollutants and/or toxic agents in the environment and/or in food matrices, thus representing a valid alternative to animal testing in analytical toxicology. Inhibition based biosensors here presented have been proved to represent alternative assays for the toxicity evaluation of warfare agents and endocrine disrupting chemicals as well as algal toxins (phycotoxins) in the contamined sea foods (mainly clams and other mollusks). Results obtained by inhibition studies performed by means of several enzymatic biosensors indicate the reliability of the proposed method and the possibility to extend such an experimental approach to other toxicants as a simple, rapid and cheap biotest, to be used easily also "on the spot"

PHARMACOLOGY, TOXICOLOGY AND ECOLOGY - THE NEW FRONTIER OF IRREVERSIBLE THERMODYNAMICS

Applicazione del formalismo della termodinamica del non equilibrio allo studio di processi dinamici di interesse farmaco-tossicologico ed ecotossicologico

Biosensori e bioreattori a tessuto vegetale intero per il controllo delle contaminazioni alimentari ed ambientali.

VENEZI

Carbonic anhydrase, CO2 transport and GABA homeostasis: an in-vitro model

In the present work data are reported on the effect played by CO2 transport, operated by carbonic anhydrase (CA), on the decarboxylation of l-glutamic acid (GA), operated by glutamic acid decarboxylase (GAD), to give γ-aminobutyric acid (GABA). It is shown that in a physico-chemical model system in which the rate of GA decarboxylation is continuously monitored by a selective GA biosensor, such a reaction is sharply affected by CA in the presence of an excess of CO2. Further experimental results, obtained in the presence of specific CA and GAD inhibitors (acetazolamide and valproic acid respectively), have shown that the synergic effect between the two enzyme-catalyzed reactions is extremely selective. In this light, it also seems necessary to reconsider the mechanism of action of the CA inhibitor, acetazolamide, used in the past in the treatment of several diseases of the central nervous system

Acid Phophatase/Glucose Oxidase Based Biosensors for the Determination of Pesticides.

This work presents new amperometric bienzymatic bioelectrodes for the determination of organophosphorus and carbamic acid type pesticides. Two different kinds of bienzymatic bioelectrodes are presented: a classical bienzymatic electrode, obtained by physicochemical immobilization of purified acid phosphatase (AP) and glucose oxidase (GOD) on the tip of an amperometric H2O2 electrode; and a hybrid biosensor, in which AP has been employed in the form of a thin layer of potato (Solanum tuberosum) tissue, endowed with a high content of enzyme activity. Both the biosensors can selectively detect glucose-6-phosphate (G6P), in the 5.0 × 10−5 −1.2 × 10−3M concentration range. Pesticides are detected, thanks to their high inhibition power towards AP, evaluated by adding the sample stepwise to a buffered solution of G6P, and recording the corresponding current change. The detection limit is therefore a function of the type of pesticide, but it can be as low as 1 μg 1−1 in the case of organophosphorus compounds. The detection limit is generally higher for carbamates, as a consequence of their weaker inhibition power towards acid phosphatase. Both bioelectrodes presented comparable values of the main physicochemical and analytical parameters evaluated for assessing their overall performance; nonetheless the plant tissue based bioelectrode exhibited a longer shelf life and a better reliability of the amperometric results

Atmospheric pollution originating from the interaction of different gaseous effluents

During the last few years, several episodes of atmospheric pollution have been reported in a limited area near Guidonia, Rome. The area contains a disposal plant, Inviolata, for the collection of municipal solid waste (MSW) and a famous thermal water resort, the Acque Albule spring, which is a source of water rich in H2S. We conducted a multiparametric study in the areas surrounding the solid waste disposal plant and the Acque Albule spring. The concentration of main gaseous effluent was continuously monitored over a period of 4 months and the data relating to the meteorologic conditions in the area during the last few decades were examined. Our results suggest that most of the atmospheric pollution is due to the interaction of different gaseous effluents. Specifically, the presence of relatively high levels of hydrogen sulfide in the atmosphere, constantly released in large amounts by the Acque Albule springs, and of biogases (mainly hydrocarbons) from the organic matter present in the solid waste continuously unloaded and stored at the disposal plant, lead to mixing and photochemical interactions between these chemical compounds, which in turn are responsible for most of the polluting effects. Such interactions are promoted by the strong solar irradiation in the area that is enhanced by the peculiar local meteorological features that do not allow the pollutants to disperse