PubMed Health⌕ Search

Biomedical subjects

M Guardigli

Publications and source records attributed to M Guardigli.

7 recordsLinked to original sources
PubMed2006

Development and validation of a sensitive and fast chemiluminescent enzyme immunoassay for the detection of genetically modified maize.

Proteins from the Cry 1 family, in particular Cry 1Ab, are commonly expressed in genetically modified Bt maize in order to control chewing insect pests. A sensitive chemiluminescent sandwich enzyme immunoassay for the detection of Cry1Ab protein from genetically modified Bt maize has been developed and validated. A Cry1Ab protein-specific antibody was immobilized on 96- or 384-well microtiter plates in order to capture the Cry1Ab toxin in the sample; the bound toxin was then detected by employing a second anti-Cry1Ab antibody and a horseradish peroxidase-labeled anti-antibody, followed by measurement of the enzyme activity with an enhanced chemiluminescent system. The chemiluminescent assay fulfilled all the requirements of accuracy and precision and exhibited limits of detection of a few pg mL(-1) Cry1Ab (3 or 5 pg mL(-1), depending on the assay format), which are significantly lower than that achievable using conventional colorimetric detection of peroxidase activity and also represent an improvement compared to previously developed Cry1Ab immunoassays. High-throughput analysis can be performed using the 384-well microtiter plate format immunoassay, which also allows one to reduce the consumption of samples and reagents. Validation of the assay, performed by analyzing certified reference materials, proved that the immunoassay is able to detect the presence of the Cry1Ab protein in certified reference samples containing as low as 0.1% of MON 810 genetically modified Bt maize. This value is below the threshold requiring mandatory labeling of foods containing genetically modified material according to the actual EU regulation.

Bacillus thuringiensis Toxins↗
PubMed2005

Antioxidant effectiveness of organically and non-organically grown red oranges in cell culture systems.

BACKGROUND: Consumers consider plant food products from organic origin healthier than the corresponding conventional plant foods. Clear experimental evidence supporting this assumption is still lacking. AIM OF THE STUDY: To determine if the organic red oranges have a higher phyto-chemical content (i. e., phenolics, anthocyanins and ascorbic acid), total antioxidant activity and in vitro bioactivity, in terms of protective effect against oxidative damage at cellular level, than nonorganic red oranges. METHODS: Total phenolics were measured using the Folin Ciocalteau assay, while total anthocyanins and ascorbic acid levels were determined by spectrophotometric and HPLC analysis, respectively. In addition, the total antioxidant activity of red orange extracts was measured by the ABTS(*+) test. The ability of red orange extracts to counteract conjugated diene containing lipids and free radical production in cultured rat cardiomyocytes and differentiated Caco-2 cells, respectively, was assessed. RESULTS: Organic oranges had significantly higher total phenolics, total anthocyanins and ascorbic acid levels than the corresponding non-organic oranges (all p < 0.05). Moreover, the organic orange extracts had a higher total antioxidant activity than non-organic orange extracts (p < 0.05). In addition, our results indicate that red oranges have a strong capacity of inhibiting the production of conjugated diene containing lipids and free radicals in rat cardiomyocytes and differentiated Caco-2 cells, respectively. Statistically higher levels of antioxidant activity in both cell models were found in organically grown oranges as compared to those produced by integrated agriculture practice. CONCLUSIONS: Our results clearly show that organic red oranges have a higher phytochemical content (i. e., phenolics, anthocyanins and ascorbic acid), total antioxidant activity and bioactivity than integrated red oranges. Further studies are needed to confirm whether the organic agriculture practice is likely to increase the antioxidant activity of other varieties of fruits and vegetables.

Agriculture↗
PubMed2001

Synthesis and screening for antiacetylcholinesterase activity of (1-benzyl-4-oxopiperidin-3-ylidene)methylindoles and -pyrroles related to donepezil.

The design, synthesis, and rapid evaluation of a new class of acetylcholinesterase (AChE) inhibitors related to donepezil are reported. A molecular dynamics simulation of the complex between AChE and one representative compound of the series showed a possible inhibitor binding mode in which favorable interactions are formed between the benzylpiperidinone moiety and some active-site residues. The biochemical evaluation of this newly synthesized series was performed using a chemiluminescent method suitable for high-throughput screening.

Acetylcholinesterase↗
PubMed2000

2,2'-bipyridine lariat calixcrowns: a new class of encapsulating ligands forming highly luminescent Eu3+ and Tb3+ complexes

A new class of calix[4]arene crown ethers with one or two bipyridines appended to the polyether ring (lariat calixcrowns) have been designed and synthesized; the luminescence properties of their Eu3+ and Tb3+ complexes have been studied in acetonitrile. In this solvent, long lifetimes for the metal emitting states and high metal-luminescence intensities obtained upon ligand excitation have been observed in both Eu3+ and Tb3+ complexes. The association constants in methanol have been determined for some of the complexes studied.

Journal Article↗
PubMed2000

Protein microdeposition using a conventional ink-jet printer.

Many recent bioanalytical systems based on immunologic and hybridization reactions in a mono- or bidimensional microarray format require technology that can produce arrays of spots containing biospecific molecules. Some microarray deposition instruments are commercially available, and other devices have been described in recent papers. We describe a system obtained by adapting a commercial ink-jet printer and used to produce mono- and bidimensional arrays of spots containing horseradish peroxidase on cellulose paper. In a few minutes, it was possible to obtain bidimensional arrays containing several thousands of spots with a diameter as low as 0.2 mm, with each of which requiring only a few nanoliters of the enzyme deposition solution. The quantity of enzyme in each spot was evaluated with a chemiluminescent reaction and a charge-coupled device-based, low-light imaging luminograph. The chemiluminescence measurements revealed that the reproducibility of the enzyme deposition was satisfactory for analytical purposes, with the variation coefficients being lower than 10% in almost all cases.

Horseradish Peroxidase↗
PubMedDate not supplied

Bio- and chemiluminescence in bioanalysis.

Analytical chemiluminescence and bioluminescence represent a versatile, ultrasensitive tool with a wide range of applications in diverse fields such as biotechnology, pharmacology, molecular biology, clinical and environmental chemistry. Enzyme activities and enzyme substrates and inhibitors can be efficiently determined when directly involved in luminescent reactions, and also when they take part in a reaction suitable for coupling to a final light-emitting reaction. Chemiluminescence detection has been exploited in the fields of flow-injection analysis and column-liquid chromatographic and capillary-electrophoretic separative systems, due to its high sensitivity when compared with colorimetric detection. It has widely been used as an indicator of reactive oxygen species formation in cells and whole organs, thus allowing the study of a number of pathophysiological conditions related to oxidative stress. Chemiluminescence represents a sensitive and rapid alternative to radioactivity as a detection principle in immunoassays for the determination of a wide range of molecules (hormones, food additives, environmental pollutants) and in filter membrane biospecific reactions (Southern, Northern, Western, dot blot) for the determination of nucleic acids and proteins. Chemiluminescence has also been used for the sensitive and specific localization and quantitation of target analytes in tissue sections and single cells by immunohistochemistry and in situ hybridization techniques. A relatively recent application regards the use of luminescent reporter genes for the development of bioassays based on genetically engineered microorganisms or mammalian cells able to emit visible light in response to specific inorganic and organic compounds. Finally, the high detectability and rapidity of bio- and chemiluminescent detection make it suitable for the development of microarray-based high throughput screening assays, in which simultaneous, multianalyte detection is performed on multiple samples.

Animals↗