Biodegradation of Aflatoxin B1 in Maize Grains and Suppression of Its Biosynthesis-Related Genes Using Endophytic Trichoderma harzianum AYM3.

Aflatoxin B1 is one of the most deleterious types of mycotoxins. The application of an endophytic fungus for biodegradation or biosuppression of AFB1 production by Aspergillus flavus was investigated. About 10 endophytic fungal species, isolated from healthy maize plants, were screened for their in vitro AFs-degrading activity using coumarin medium. The highest degradation potential was recorded for Trichoderma sp. (76.8%). This endophyte was identified using the rDNA-ITS sequence as Trichoderma harzianum AYM3 and assigned an accession no. of ON203053. It caused a 65% inhibition in the growth of A. flavus AYM2 in vitro. HPLC analysis revealed that T. harzianum AYM3 had a biodegradation potential against AFB1. Co-culturing of T. harazianum AYM3 and A. flavus AYM2 on maize grains led to a significant suppression (67%) in AFB1 production. GC-MS analysis identified two AFB1-suppressing compounds, acetic acid and n-propyl acetate. Investigating effect on the transcriptional expression of five AFB1 biosynthesis-related genes in A. flavus AYM2 revealed the downregulating effects of T. harzianum AYM3 metabolites on expression of aflP and aflS genes. Using HepaRG cell line, the cytotoxicity assay indicated that T. harazianum AYM3 metabolites were safe. Based on these results, it can be concluded that T. harzianum AYM3 may be used to suppress AFB1 production in maize grains.

The Efficacy of Green Synthesized Nanosilver in Reducing the Incidence of Post-Harvest Apple Fruit Brown Rot.

This study aimed to green synthesize nanosilver (AgNPs) using black tea extract and use it as a nanopreservative to increase the shelf life of stored apple fruits. Ultraviolet visible absorption (UV-vis) analysis of AgNPs recorded two λ max values at 260 and 452 nm. Transmission electron microscope and dynamic light scattering analyses showed that AgNPs are spherical in shape and have an average size of 20 and 170.6 nm, respectively, with a zeta potential of -20.06 mV. An in vitro assay confirmed the antifungal potential of AgNPs against M. fructigena when applied at 200 mg/L and preincubated for 4 days, reducing the radial growth by 96.1%. At the same dose and preincubation period, AgNPs caused a significant reduction in the diameter and fresh weight of brown rotted lesions in apple fruits artificially coinoculated with the pathogen by 77.4% and 84.4%, respectively. AgNPs caused the leakage of proteins and DNA from M. fructigena conidia and did not express cytotoxicity against the human HaCaT cell lines. Accordingly, green synthesized AgNPs are eco-friendly and economical and do not pose harm to human health; thus, they could be used as an effective nanopreservative in apple fruit stores to reduce the incidence of brown rot disease.

Molecularly Imprinted Electrochemical Sensor-Based Fe2O3@MWCNTs for Ivabradine Drug Determination in Pharmaceutical Formulation, Serum, and Urine Samples.

Ivabradine hydrochloride (IVR) is a medically important drug because of its ability to lower the heart rate. Techniques reported for IVR determination were expensive, laborious, besides being of poor selectivity. In this study, iron oxide @ carbon nanotube (Fe2O3@MWCNTs) nanocomposite and molecularly imprinted polymer (MIP) were synthesized and used in the fabrication of carbon paste electrodes (CPEs) for the potentiometric detection of IVR in biological and pharmaceutical samples. CPEs of the best sensor were formulated from graphite (41 wt%) as a carbon source, MIP (3 wt.%) as an ionophore, Fe2O3@MWCNTs (5 wt%) as a modifier, and nitrophenyl octyl ether (NPOE, 51 wt.%) as a conductive oil so-called plasticizer. The best sensor exhibits a Nernstian slope (response) of 56 mV decade-1 within the IVR concentration range from 1.0 × 10-3 M to 9.8 × 10-8 M with high selectivity against interfering species (ascorbic, maltose, glucose, lactose, dopamine, glycine) over those reported earlier. The use of Fe2O3@MWCNTs together with MIP in the electrode formulation was found to improve the limit of detection (LOD) from 630 to 98 nM along with high reversibility, a short response time of 30 s, and a good lifetime of more than 2 weeks. The sandwich membrane (SMM) method was used to quantify the H-bonding complexing strength of the MIP binding sites for IVR with Log ß ILn = 11.33. The constructed sensors were successfully applied for the IVR determination in blood serum, urine, and commercial formulations (Savapran®) with high sensitivity.

Molecularly imprinted polymers based biomimetic sensors for mosapride citrate detection in biological fluids.

Computational modeling was applied to study the intermolecular interactions in the pre-polymerization mixture and find a suitable functional monomer to use in the design of a new molecularly imprinted polymer (MIP) for mosapride citrate which is considerably a large molecule (as the citrate ion is also included in calculations as it has centers that can take part in interaction with monomer via hydrogen bonding). Based on these calculations, methacyrlic acid (MAA) was selected as a suitable functional monomer. Mosapride citrate selective MIP and a non-imprinted polymer (NIP) were synthesized and characterized using FTIR, TGA and SEM and then incorporated in carbon paste electrodes (CPEs). The designed modified sensor revealed linear responses in the ranges of 1×10-4-8×10-7 and 8×10-7-8×10-8molL-1 with a limit of detection (LOD) of 2.6×10-8molL-1. The results of the sensor exhibited high selectivity over interfering species and could be applied for the determination of mosapride citrate in pure solutions, pharmaceutical preparations, urine and human serum samples.

Molecularly imprinted polymer-based bulk optode for the determination of itopride hydrochloride in physiological fluids.

We report here for the first time on the use of Molecularly Imprinted Polymers as modifiers in bulk optodes, Miptode, for the determination of a pharmaceutical compound, itopride hydrochloride as an example in a concentration range of 1×10(-1)-1×10(-4)molL(-1). In comparison to the optode containing the ion exchanger only (Miptode 3), the optode containing the ion exchanger and the MIP particles (Miptode 2) showed improved selectivity over the most lipophilic species, Na(+) and K(+), by more than two orders of magnitude. For instance, the optical selectivity coefficients using Miptode 2, [Formula: see text] , were as follow: NH4(+)˂-6; Na(+)=-4.0, which were greatly enhanced in comparison with that obtained by Miptode 3. This work opens a new avenue for using miptodes for the determination of all the pharmaceutical preparations without the need for the development of new ionophores.

Preparation and application of molecularly imprinted polymer for isolation of chicoric acid from Chicorium intybus L. medicinal plant.

Molecularly imprinted polymer (MIP) was synthesized and applied for the extraction of chicoric acid from Chicory herb (Chicorium intybus L.). A computational study was developed to find a suitable template to functional monomer molar ratio for MIP preparations. The molar ratio was chosen based on the comparison of the binding energy of the complexes between the template and functional monomers. Based on the computational results, eight different polymers were prepared using chicoric acid as the template. The MIPs were synthesized in a non-covalent approach via thermal free-radical polymerization, using two different polymerization methods, bulk and suspension. Batch rebinding experiments were performed to evaluate the binding properties of the imprinted polymers. The best results were obtained with a MIP prepared using bulk polymerization with 4-vinylpyridine (4-VP) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinker with a molar ratio of 1:4:20. The best MIP showed selective binding ability toward chicoric acid in the presence of the template's structural analogues, caffeic acid, caftaric acid and chlorogenic acid.

Synthesis and application of a molecularly imprinted polymer for the voltammetric determination of famciclovir.

A molecularly imprinted polymer (MIP) was synthesized and applied as additive within a carbon paste electrode for the cyclic voltammetric determination of famciclovir (FCV). Complementary computational studies were performed to study the intermolecular interactions in the pre-polymerization mixture. Derived from the computational studies, four MIP ratios were synthesized and their performance was evaluated using equilibrium rebinding assays. The MIP with the highest binding capacity was selected. A linear response was obtained in the range of 2.5×10(-6)-1.0×10(-3)M with a limit of detection at 7.5×10(-7)M. Finally, the developed MIP-voltammetry system was successfully applied for the determination of FCV in pure solutions and pharmaceutical preparations.

Co-occurrence of mycoflora, aflatoxins and fumonisins in maize and rice seeds from markets of different districts in Cairo, Egypt.

The mycoflora and mycotoxins contamination of commercial maize and rice grains collected from local markets of the major five zones of the province of Cairo, Egypt, represented by 20 different districts were studied. A total number of about 23 species belonging to 12 different genera of fungi were isolated and identified. About 70% of the samples were infected with Aspergillus flavus and Aspergillus niger, with percentages of 33%, 40% recovered from maize and 46%, 27% recovered from rice, respectively. The percentages of infection of maize ranged from 16% to 142%. The percentages of infection of rice seeds ranged from 6% to 93%. Total aflatoxins and fumonisins detected in maize averaged 9.75 and 33 µg/kg, respectively. Total aflatoxins and fumonisins detected in rice averaged 5.15 and 1014 µg/kg, respectively.