Oxidase Enzyme Research Articles

Microplastics shaped performance, microbial ecology and community assembly in simultaneous nitrification, denitrification and phosphorus removal process

The widespread use of microplastics (MPs) has led to an increase in their discharge to wastewater treatment plants. However, the knowledge of impact of MPs on macro-performance and micro-ecology in simultaneous nitrification, denitrification, and phosphorus removal (SNDPR) systems is limited, hampering the understanding of potential risks posed by MPs. This study firstly comprehensively investigated the performance, species interactions, and community assembly under polystyrene (PS) and polyvinyl chloride (PVC) exposure in SNDPR systems. The results showed under PS (1, 10 mg/L) and PVC (1, 10 mg/L) exposure, total nitrogen removal was reduced by 3.38–10.15 %. PS and PVC restrained the specific rates of nitrite and nitrate reduction (SNIRR, SNRR), as well as the activities of nitrite and nitrate reductase enzymes (NIR, NR). The specific ammonia oxidation rate (SAOR) and activity of ammonia oxidase enzyme (AMO) were reduced only at 10 mg/L PVC. PS and PVC enhanced the size of co-occurrence networks, niche breadth, and number of key species while decreasing microbial cooperation by 5.85–13.48 %. Heterogeneous selection dominated microbial community assembly, and PS and PVC strengthened the contribution of stochastic processes. PICRUSt prediction further revealed some important pathways were blocked by PS and PVC. Together, the reduced TN removal under PS and PVC exposure can be attributed to the inhibition of SAOR, SNRR, and SNIRR, the restrained activities of NIR, NR, and AMO, the changes in species interactions and community assembly mechanisms, and the suppression of some essential metabolic pathways. This paper offers a new perspective on comprehending the effects of MPs on SNDPR systems.

Inactivation kinetics of polyphenol oxidase and peroxidase enzymes in buffer solutions by ultraviolet light sources at multiple UV-C wavelengths

This study aimed to evaluate the effect of multiple wavelengths of UV-C light sources on the inactivation of polyphenol oxidase (PPO) and peroxidase (POD) in buffer solutions. Enzyme solutions were treated with a UV-C excimer lamp (EL) emitting at 222 nm, low-pressure mercury (LPM) lamp at 253.7 nm, four UV-LEDs sources emitting at 255, 265, 275 and 285 nm, and a novel pulsed UV-C lamp (PL) emitting at 232, 242, 261 and 272 nm. Three kinetic models were used to compare UV-C wavelengths enzymatic inactivation efficacy considering the volume average fluence for 90% reduction (HD). Validation of kinetic parameters was performed under continuous-flow treatment in a UV-C LED and EL system. EL treatment resulted in the highest inactivation efficacy of PPO and POD enzymes with HD of 52.8 and 74.8 mJ/cm2, respectively. PL inactivation efficacy for both enzymes was higher than with LPM lamp or UV-LEDs. The two-component first-order model best described the inactivation of PPO and POD in a buffer solution. The adjusted kinetic parameters for this model were validated under UV-C light continuous flow processing. This study contributes to the development of liquid food treatment by ultraviolet technology.

Investigation of the Interaction of Monoamine Oxidase (MAO) Inhibitor Biscoumarins with Hemoglobin and Albumin Using Multi-Spectroscopic Techniques and Molecular Docking

Coumarin and their derivatives, such as biscoumarins, which are found as active ingredients in a variety of drugs, possess a wide range of biological activities. In this paper, the inhibitory effects of biscoumarin derivatives B1 and B2 on monoamine oxidase (MAO) enzyme activity were studied. Their binding mechanism to bovine serum hemoglobin (BHb) and bovine serum albumin (BSA) was investigated using molecular docking and multi-spectroscopic methods such as absorption, fluorescence, and synchronized fluorescence spectroscopy. The fluorescence quenching processes were analyzed using the Stern-Volmer, Lineweaver-Burk, and Hill methods. In this regard, Stern-Volmer quenching constants (Ksv), Lineweaver-Burk constants (KLB), and binding constants (Ka) were calculated at three temperatures (298, 310 and 322 K). The fluorescence studies showed that the binding of biscoumarins to BHb or BSA was a driven by static quenching. The Ka values of B2 to BHb and BSA (2179.11 and 18453.98 x 105 M-1) was larger than B1 at corresponding temperature (62.75 and 599.90 x105 M-1 for BHb and BSA, respectively), which indicates that the affinity of B2 toward the proteins were higher than that of B1. Moreover, thermodynamic parameters explained that hydrogen bonds were the main binding force stabilizing the protein-ligand complexes. Additionally, molecular docking studies have revealed binding energies, ligand efficiency values, and interactions with amino acid residues of proteins. The results of these investigations may be helpful in analyzing drug-protein binding of biscoumarins for potential future applications.

Comparative Effect of Seed Coating and Biopriming of Bacillus aryabhattai Z-48 on Seedling Growth, Growth Promotion, and Suppression of Fusarium Wilt Disease of Tomato Plants.

Beneficial plant microbes can enhance the growth and quality of field crops. However, the benefits of microbes using cheap and efficient inoculation methods are still uncommon. Seed coating with biocontrol agents can reduce the amount of inocula along with having the potential for large-scale application. Hence, in this research work, the comparative potential of tomato seed coating and biopriming with Bacillus aryabhattai Z-48, harboring multiple plant-beneficial traits, to suppress Fusarium wilt disease along with its beneficial effect on seedling and plant growth promotion was analyzed. Among two bacterial strains, B. aryabhattai Z-48 was able to antagonize the mycelial growth of Fusarium oxysporum f.sp. lycopersici in vitro and its application as a seed coating superiorly benefited seedling traits like the germination percentage, vigor index, and seedling growth index along with a reduced germination time. The seed coating with B. aryabhattai Z-48 resulted in significant increases in the shoot length, root length, dry biomass, and total chlorophyll contents when compared with the bioprimed seeds with the same bacterial strain and non-inoculated control plants. The seed coating with B. aryabhattai Z-48 significantly reduced the disease index (>60%) compared with the pathogen control during pot trials. Additionally, the seed coating with B. aryabhattai Z-48 resulted in a significantly higher production of total phenolics, peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase enzyme in tomato plants. The GC/MS-based non-targeted metabolic profiling indicated that the seed coating with B. aryabhattai Z-48 could cause large-scale metabolite perturbations in sugars, sugar alcohols, amino acids, and organic acids to increase the fitness of tomato plants against biotic stress. Our study indicates that a tomato seed coating with B. aryabhattai Z-48 can improve tomato growth and suppress Fusarium wilt disease effectively under conventional agricultural systems.

Melatonin postharvest spray influence on white mulberry browning, storage life, and biochemical changes

White mulberry (Morus alba L.) fruit is a rich source of bioactive compounds, but it is highly perishable and vulnerable to browning. In the current study, melatonin at concentrations of 0, 125, 250, 500, and 1000 µM was sprayed on mulberry fruit and stored at 1 °C for 12 d. Melatonin treatment yielded the lowest browning index during storage time. This reduction was accompanied by a significant decrease in malondialdehyde, H2O2 and polyphenol oxidase enzyme activity. The results showed that melatonin reduced weight loss and maintained pH, as well as total soluble solids. Furthermore, the total phenol, total flavonoids and ascorbic acid contents in treated fruit were significantly higher than in an untreated fruit, which was accompanied by an increase in antioxidant capacity. With assuming 40 % browning would render the fruit unmarketable, melatonin treatments could extend mulberry storage life beyond 8 days. The 500 and 1000 μM melatonin treatments showed the most effective results. In conclusion, exogenous melatonin application can be considered a safe and promising procedure to maintain the quality of mulberry fruit during low-temperature storage.

Exploring the multifaceted bioactivities of Lavandula pinnata L. essential oil: promising pharmacological activities.

Introduction: This study investigates the biological activities of Lavandula pinnata essential oil (LPEO), an endemic lavender species from the Canary Islands, traditionally used in treating various ailments. Methods: LPEO was extracted by hydrodistillation and analyzed using GC-MS. Antioxidant activity was assessed by DPPH radical scavenging and total antioxidant capacity assays. Antimicrobial activity was evaluated by disc diffusion, MIC, MBC, and MFC determination against bacterial (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Pseudomonas aeruginosa) and fungal (Candida glabrata, Rhodotorula glutinis, Aspergillus niger, Penicillium digitatum) strains. Antidiabetic and anti-gout potential were investigated through α-amylase, α-glucosidase, and xanthine oxidase inhibition assays. Antityrosinase activity was determined using a modified dopachrome method. Cytotoxicity was assessed by MTT assay against breast (MCF-7, MDA-MB-468), liver (HepG2), colon (HCT-15) cancer cells, and normal cells (PBMCs). Results and discussion: LPEO exhibits potent antiradical activity (IC50 = 148.33 ± 2.48μg/mL) and significant antioxidant capacity (TAC = 171.56 ± 2.34μg AA/mg of EO). It demonstrates notable antibacterial activity against four strains (Staphylococcus aureus, Micrococcus luteus, Escherichia coli, and Pseudomonas aeruginosa) with inhibition zones ranging from 18.70 ± 0.30mm to 29.20 ± 0.30mm, along with relatively low MIC and MBC values. LPEO displays significant antifungal activity against four strains (Candida glabrata, Rhodotorula glutinis, Aspergillus niger, and Penicillium digitatum) with a fungicidal effect at 1mg/mL, surpassing the positive control (cycloheximide), and MIC and MFC values indicating a fungicidal effect. It exhibits substantial inhibition of xanthine oxidase enzyme (IC50 = 26.48 ± 0.90μg/mL), comparable to allopurinol, and marked inhibitory effects on α-amylase (IC50 = 31.56 ± 0.46μg/mL) and α-glucosidase (IC50 = 58.47 ± 2.35μg/mL) enzymes.The enzyme tyrosinase is inhibited by LPEO (IC50 = 29.11 ± 0.08mg/mL). LPEO displays moderate cytotoxic activity against breast, liver, and colon cancer cells, with low toxicity towards normal cells (PBMC). LPEO exhibits greater selectivity than cisplatin for breast (MCF-7) and colon (HCT-15) cancer cells but lower selectivity for liver (HepG2) and metastatic breast (MDA-MB-468) cancer cells. These findings suggest the potential of LPEO as an antioxidant, antimicrobial, anti-gout, antidiabetic, and anticancer agent.

Use of Biosensors within the Oral Environment for Systemic Health Monitoring—A Systematic Review

Scientific advances in biosensor technology are leading to the potential of wearable biosensors for salivary biomarker detection. This review aims to identify the current status of intraoral biosensor technology that can be used to monitor systemic diseases. A total of 11 studies were identified for inclusion, which included nine different devices, including modified mouthguards, retainers, toothbrushes, and dental floss. Out of the 11 studies, 8 studied continuous biomarker monitoring, and the remaining 3 were point-of-care applications. A total of seven biomarkers were studied, six of which investigated the intraoral detection of salivary glucose levels using glucose oxidase enzyme. All the sensors demonstrated excellent sensitivity (minimum R = 0.9928) and selectivity. The study designs were proof of concept, with five studies including in vivo components. We concluded that while there are established links between salivary biomarkers and systemic health, there is a lack of mature intraoral biosensor research. Refinement of biosensor design and data analysis is required to improve patient acceptability by promoting more discrete, real-time, low-cost, and wireless devices. Further research that utilises the biosensor technology in large controlled clinical trials will be required to confirm clinical applicability before intraoral biosensor technology can be integrated into routine health monitoring.

Oxalic acid alleviates chilling injury and positively influences post-harvest parameters of sweet bell pepper by affecting glycine betaine accumulation, cells respiration rate and NADPH oxidase enzyme activity during cold storage

Bell pepper as tropical crop and warm-season vegetable is sensitive to cold storage under temperatures below 7.5 °C. The purposes of the current study were to investigate the influence of pre-harvest treatment of oxalic acid (OA 0, 1, 5, 10, and 15 mM) on some of most important morphological, physiological and bio-chemical characteristics of red bell pepper cv. "2090 Westland" at post-harvest stage, and assessment of mechanisms and enzymatic pathways of crop response to OA treatments. OA treatments greatly reduced the chilling index, and the positive effects of treatments enhanced by increasing the concentration of OA. The energy level (ATP content) of pepper fruits decreased with extending storage duration, but OA treatment maintained the ATP content of fruits. On 24 d of storage, the highest and lowest activity rate of NADPH oxidase enzyme was recorded in control and 10 mM-treated fruits. Extending storage duration led to a significant increase in cells respiration rate, but this increase was more pronounced in control. Oxalic acid as low-risk and environmentally friendly compound could be an appropriate choice to apply as pre-harvest treatment in order to extend shelf-life of bell pepper fruits during cold storage under 4 ºC. The most important mechanisms reaction of OA are enhancing of enzymatic and non-enzymatic antioxidant activities, increasing the accumulation rate of osmoprotectants and regulation of energy metabolism of cells. Pre-harvest treatment of OA 10 mM could be introduced as efficient technique to overcome adverse effects of chilling stress on post-harvest characteristics of bell pepper.

Can Sb(III)-oxidizing prokaryote also oxidize As(III) under aerobic and anaerobic conditions, and vice versa?

Sb(III) and As(III) share similar chemical features and coexist in the environment. However, their oxidase enzymes have completely different sequences and structures. This raises an intriguing question: Could Sb(III)-oxidizing prokaryotes (SOPs) also oxidize As(III), and vice versa? Regarding this issue, previous investigations have yielded unclear, incorrect and even conflicting data. This work aims to address this matter. First, we prepared an enriched population of SOPs that comprises 55 different AnoA genes, lacking AioAB and ArxAB genes. We found that these SOPs can oxidize both Sb(III) and As(III) with comparable capabilities. To further confirm this finding, we isolated three cultivable SOP strains that have AnoA gene, but lack AioAB and ArxAB genes. We observed that they also oxidize both Sb(III) and As(III) under both anaerobic and aerobic conditions. Secondly, we obtained an enriched population of As(III)-oxidizing prokaryotes (AOPs) from As-contaminated soils, which comprises 69 different AioA genes, lacking AnoA gene. We observed that the AOP population has significant As(III)-oxidizing activities, but lack detectable Sb(III)-oxidizing activities under both aerobic and anaerobic conditions. Therefore, we convincingly show that SOPs can oxidize As(III), but AOPs cannot oxidize Sb(III). These findings clarify the previous ambiguities, confusion, errors or contradictions regarding how SOPs and AOPs oxidize each other’s substrate.

Enhancing postharvest quality and extending storage life of Booth 7 avocado (Persea americana Mill.) fruit through sodium nitroprusside (SNP) application during low-temperature storage

Postharvest quality plays a crucial role in marketability, consumer acceptability, and shelf life of avocados. This study investigates the efficacy of nitric oxide (NO) on postharvest physiology and quality of Booth 7 avocados treated with different concentrations of sodium nitroprusside (SNP) - a nitric oxide-releasing compound. Booth 7 avocados were immersed in SNP solutions (0.5 mM, 1.0 mM, and 1.5 mM), while the control fruit was immersed in distilled water for 15 min. After treatment, the fruit was stored at a temperature (T) of 8 ± 1 °C and relative humidity (RH) of 90 ± 5% for 35 days, during which the control fruit exhibited complete deterioration. The results revealed that Booth 7 avocados treated with 1.5 mM SNP concentration exhibited delayed quality changes during storage, reduced ethylene production and respiration rate, reduced alterations in soluble solids and acid content of the fruit flesh, as well as delayed changes in flesh and peel color. Additionally, the activity of total phenolic compounds (TPC), polygalacturonase (PG), and polyphenol oxidase (PPO) enzymes increased significantly, while the activity of the pectin methyl esterase (PME) enzyme was reduced. In conclusion, SNP treatment improved the quality and can be utilized as a potential postharvest preservative for Booth 7 avocados. For producers and distributors, the use of SNP in avocado postharvest management offers the potential to extend shelf life without compromising fruit quality.

ULASAN SISTEMATIK KEATAS PENGAPLIKASIAN BIOPENDERIA BERASASKAN PERENCATAN ENZIM SEBAGAI KAEDAH SARINGAN AWAL UNTUK PEMANTAUAN ALAM SEKITAR DAN KESELAMATAN MAKANANEMANTAUAN ALAM SEKITAR DAN KESELAMATAN MAKANAN

In this article, the latest discoveries in the development of biosensors based on enzyme inhibition are reviewed. Due to their excellent selectivity and sensitivity, they represent a significant alternative method to conventional analytical methods; which is a method of analysis that only relies on the generation of instrumentation data without any preliminary screening. Basically, biosensors are able to convert biological activity into a quantifiable signal. These enzyme inhibition-based biosensors have a wide range of applications in the fields of environmental safety, food safety, and clinical analysis since toxic substances containing heavy metals and pesticides are the most effective inhibitors of enzymes. This paper is aimed at exploring the methods used and the sensitivity to various inhibitors for biosensors based on the inhibition of enzymes such as glucose oxidase, urease, tyrosinase, cholinesterase, and other enzymes.

Construction of a Conductive Polymer/AuNP/Cyanobacteria-Based Biophotovoltaic Cell Harnessing Solar Energy to Generate Electricity via Photosynthesis and Its Usage as a Photoelectrochemical Pesticide Biosensor: Atrazine as a Case Study.

In this research, a cyanobacteria (Leptolyngbia sp.)-based biological photovoltaic cell (BPV) was designed. This clean energy-friendly BPV produced a photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on the gold electrodes. In the cell, the photoanode was first coated with a gold-modified poly 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzamine polymer, P(SNS-Aniline). Thioaniline-functionalized gold nanoparticles were used to provide a cross-link formation with bis-aniline conductive bonds with the conductive polymer using electrochemical techniques. Leptolyngbia sp., one of the cyanobacteria that can convert light energy into chemical energy, was attached to this layered electrode surface. The cathode of the cell was attached to the gold electrode surface with P(SNS-Aniline). Then, the bilirubin oxidase (BOx) enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light, thanks to cyanobacteria, oxidized and split water, and oxygen was obtained at the photoanode electrode. At the cathode electrode, the oxygen gas was reduced to water by the bioelectrocatalytic method. To obtain a high photocurrent from the BPV, necessary optimizations were made during the design of the system to increase electron transport and strengthen its transfer. While the photocurrent value obtained with the designed BPV in optimum conditions and in the pseudosteady state was 10 mA/m2, the maximum power value obtained was 46.5 mW/m2. In addition to storing the light energy of the system, studies have been carried out on this system as a pesticide biosensor. Atrazine biosensing via the BPV system was analytically characterized between 0.1 and 1.2 μM concentrations for atrazine, and a very low detection limit was found as 0.024 μM. In addition, response time and recovery studies related to pesticide biosensor properties of the BPV were also investigated.

Affinity gel synthesis from the p-aminobenzoic acid derivative 4-amino-2-methylbenzoic acid and purification of polyphenol oxidase from various plant sources

The polyphenol oxidase (PPO) enzyme, which causes enzymatic browning, has been repeatedly purified from fruit and vegetables by affinity chromatography. In the present research, Sepharose 4B-l-tyrosine-4-amino-2-methylbenzoic acid, a novel affinity gel for the purification of the PPO enzyme with high efficiency, was synthesized. Additionally, Sepharose 4B-l-tyrosine-p-aminobenzoic acid affinity gel, known in the literature, was also synthesized, and 9.02, 16.57, and 28.13 purification folds were obtained for the PPO enzymes of potato, mushroom, and eggplant by the reference gel. The PPO enzymes of potato, mushroom, and eggplant were purified 41.17, 64.47, and 56.78-fold from the new 4-amino-2-methylbenzoic acid gel. Following their isolation from the new affinity column, the assessment of PPO enzyme purity involved the utilization of SDS-PAGE. According to the results from SDS-PAGE and native PAGE, the molecular weight of each enzyme was 50 kDa. Then, the inhibition effects of naringin, morin hydrate, esculin hydrate, homovanillic acid, vanillic acid, phloridzin dihydrate, and p-coumaric acid phenolic compounds on purified potato, mushroom, and eggplant PPO enzyme were investigated. Among the tested phenolic compounds, morin hydrate was determined to be the most potent inhibitor on the potato (Ki: 0.07 ± 0.03 μM), mushroom (Ki: 0.7 ± 0.3 μM), and eggplant (Ki: 4.8 ± 1.2 μM) PPO enzymes. The studies found that the weakest inhibitor was homovanillic acid for the potato (Ki: 1112 ± 324 μM), mushroom (Ki: 567 ± 81 μM), and eggplant (Ki: 2016.7 ± 805.6 μM) PPO enzymes. Kinetic assays indicated that morin hydrate was a remarkable inhibitor on PPO.

Gene Expression and Prognostic Value of NADPH Oxidase Enzymes in Breast Cancer.

NADPH oxidase enzymes (NOX) are involved in all stages of carcinogenesis, but their expression levels and prognostic value in breast cancer (BC) remain unclear. Thus, we aimed to assess the expression and prognostic value of NOX enzymes in BC samples using online databases. For this, mRNA expression from 290 normal breast tissue samples and 1904 BC samples obtained from studies on cBioPortal, Kaplan-Meier Plotter, and The Human Protein Atlas were analyzed. We found higher levels of NOX2, NOX4, and Dual oxidase 1 (DUOX1) in normal breast tissue. NOX1, NOX2, and NOX4 exhibited higher expression in BC, except for the basal subtype, where NOX4 expression was lower. DUOX1 mRNA levels were lower in all BC subtypes. NOX2, NOX4, and NOX5 mRNA levels increased with tumor progression stages, while NOX1 and DUOX1 expression decreased in more advanced stages. Moreover, patients with low expression of NOX1, NOX4, and DUOX1 had lower survival rates than those with high expression of these enzymes. In conclusion, our data suggest an overexpression of NOX enzymes in breast cancer, with certain isoforms showing a positive correlation with tumor progression.

Facile chemiresistive biosensor functionalized with PANI/GOx and novel green synthesized silver nanoparticles for glucose sensing

This article presents a Glossy Photo-Paper (GPP) based Screen-Printed Chemiresistive Interdigitate Electrode (SPCIDE) for enzymatic glucose sensing. A facile inexpensive screen-printing method was used to print the low sheet resistance Interdigitate Electrodes (IDEs) with graphene as conductive ink on the proposed GPP. The screen-printed IDE was functionalized with Polyaniline (PANI) material by drop-cast technique to create a chemiresistive matrix. Further, for selective sensing of glucose, Glucose Oxidase (GOx) enzymes with Green Synthesized Silver Nanoparticles (GS-AgNPs) were immobilized on the PANI material. The proposed GPP-based SPCIDE sensor was used to detect glucose using amperometric measurements. With a correlation coefficient (R2) of 0.9803 and a lower Limit of Detection (LOD) equal to 198 nM, the proposed SPCIDE glucose sensor displays a linear association between change in current and corresponding glucose concentration in the range of 198 nM to 30 mM. An experimental result shows that the created SPCIDE sensor has a sensitivity of 291.19 µA mM−1 cm−2. The study shows that the proposed method may be used to produce facileGPP-based glucose sensors that are inexpensive, eco-friendly, bio-synthesizable, and biodegradable. This may result in developing a Point-of-Care (PoC) diagnostic kit for glucose testing as needed.

Design of a Novel Green Algae‐Based Biological Photovoltaic Cell with High Photocurrent and a Photoelectrochemical Biosensing Approach Utilizing the BPV for Pesticide Analysis in Water

AbstractIn this research, a green alga (Paulschulziapseudovolvox sp.) based biological photovoltaic cell (BPV) was designed. This clean energy‐friendly BPV produced photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on gold electrodes. In the cell, the photoanode was first coated with a gold‐modified poly 4‐(2,5‐di(thiophen‐2‐yl)‐1H‐pyrrol‐1‐yl)benzamine polymer, (P(SNS‐NH2)). Cytochrome C (Cyt. C) material was used to provide crosslink formation with bis‐aniline covalent bonds with the conductive polymer using electrochemical techniques. Paulschulziapseudovolvox sp., one of the green algae that can convert light energy into chemical energy, is attached to this layered electrode surface. The cathode of the cell is attached to the gold electrode surface with poly 4‐(4HDithieno[3,2‐b : 2′,3′‐d]pyrrole‐4‐yl)aniline (P(DTP‐Aryl‐Amine)). Then, the bilirubin oxidase enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light thanks to green algae, oxidizes and splits water, and oxygen is obtained at the photoanode electrode. At the cathode electrode, the oxygen gas is reduced to water by the bio‐electro‐catalytic method. To obtain high photocurrent from the BPV, necessary electrochemical and chemical optimizations were made during the design of the system to increase the amount of electrons that were transferred and fasten its transfer rate. While the photocurrent value generated by the designed BPV in optimum conditions and in the pseudo‐steady state is 10 mA/m2, the maximum power value obtained is 46.5 mW/m2. In addition to the production of the green algae‐based BPV generating highly efficient electricity which is the main of target of this study, some studies have also been carried out to show whether this system can be used as a pesticide biosensor. Atrazine and diuron biosensing via the BPV system was analytically characterized and recovery and interference studies related to pesticide biosensor property of the BPV were also investigated.

Alternative products for controlling Sclerotinia sclerotiorum in vivo AND in vitro in canola crops

Products that activate plant defense mechanisms, such as white mold, may increase the disease control spectrum in canola crops as an alternative to chemical control for disease management, aiming at lower environmental impacts and selection pressure on pathogens. This study evaluated Sclerotinia sclerotiorum control and resistance induction in canola crops with alternative products. In vitro and detached leaf experiments were conducted in a laboratory, and in vivo experiments occurred in a greenhouse. High Roots®; V6®; Maxi Flor®; Wert Plus®; potassium, manganese, and copper phosphites; manganese; procymidone fungicide; and Ascophyllum nodosum, Bacillus subtilis, and Bacillus thuringiensis extracts assessed S. sclerotiorum mycelial growth in vitro in detached leaves, white mold severity in a greenhouse, and enzymatic analysis in leaf tissues. The last two experiments also received the acibenzolar-S-methyl and Trichoderma asperellum treatments. S. sclerotiorum mycelial growth showed 100% inhibition under B. subtilis and Wert Plus® at 1000 ppm and procymidone at 100 and 1000 ppm in vitro. The procymidone and B. subtilis treatments in detached leaves inhibited 100% of fungus growth. The greenhouse experiments with lower severity were procymidone, copper phosphite, B. thuringiensis, B. subtilis, manganese phosphite, potassium phosphite, High Roots®, and V6®. Higher peroxidase enzyme activity occurred in plants treated with acibenzolar-S-methyl, copper phosphite, and fungicide 48 hours after pathogen inoculation. The polyphenol oxidase enzyme did not show activity. Alternative products were responsive and may aid the chemical control of white mold in canola crops.

Сенсорное покрытие на основе липидного ленгмюровского монослоя с молекулами фермента глюкозооксидазы

A sensor coating was created based on a Langmuir monolayer of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) with immobilized molecules of the enzyme glucose oxidase and its sensor properties were studied. The process of incorporation of glucose oxidase enzyme molecules into a Langmuir monolayer of phospholipid DPPE molecules was studied using the compression isotherm method. Adsorption of glucose oxidase molecules has an expanding effect on the Langmuir monolayer of DPPE and leads to an increase in the area per molecule from 32.5 Å2 to 49 Å2 and a decrease in the compression modulus of the monolayer from 133 mN/m to 83 mN/m. Also, the adsorption of glucose oxidase leads to an increase in the desorption coefficient of the monolayer into the kd subphase from 0.5·10-3 to 1.2·10-3. The morphology of films with immobilized enzyme molecules at different adsorption times was characterized by atomic force microscopy. Increasing the enzyme adsorption time leads to a decrease in the surface roughness of the formed film from 3.6 nm at 5 minutes to 2.4 nm at 60 minutes. The formed DPPE monolayers with immobilized enzyme molecules were transferred to graphite electrodes. Their sensory properties were studied using cyclic voltammetry and impedance measurements. The resulting coatings were sensitive to glucose in solutions with concentrations from 0 to 1 mg/ml. The presence of a linear concentration dependence of the maximum and minimum currents and resistances in the specified concentration range makes the created films promising for use as touch coatings.

Prevalence and Clinical Picture of Diamine Oxidase Gene Variants in Children and Adolescents with Attention Deficit Hyperactivity Disorder: A Pilot Study.

Background: Attention Deficit Hyperactivity Disorder (ADHD) is the most prevalent neurodevelopmental disorder worldwide. The diamine oxidase enzyme (DAO) is responsible for the histamine gastrointestinal degradation. Its deficient functioning may implicate an excess of histamine in the body. The excess of histamine (histamine intolerance, HIT) has been related with a growing number of diseases and pseudo-allergic symptomatology. However, data on the relationship between the DAO enzyme, HIT, and ADHD are lacking. The main objective of this pilot is to study the prevalence of the four most relevant SNP variants of the AOC1 gene affecting DAO enzyme functionality in a sample of patients diagnosed with ADHD attending child and adolescent mental health services. Methods: In a cohort of 303 participants, we measured the SNP variants of the AOC1 gene. Results: The prevalence of having at least one minor dysfunctional allele was 78.8%. No relationship between ADHD severity and DAO deficiency was found. However, some AOC1 gene variants associated with DAO deficiency were related to several meaningful medical comorbidities. Furthermore, we found a strong association between DAO activity and the intelligence quotient, particularly in working memory. Conclusions: Some SNP variants of the AOC1 gene associated with DAO deficiency are related to some medical comorbidities and cognitive dysfunction in ADHD children and adolescents. Studies including patients with other diagnoses and healthy controls and bigger samples are warranted to confirm our preliminary results.

Evaluating the effects of chitosan incorporated with seabuckthorn leaf extract composite edible coatings on the shelf life of peach (Prunus persica L.) fruits

Peaches are highly nutritious and delicious fruits with a limited shelf life. The present study was aimed to test the efficiency of chitosan (CHI) coatings incorporated with seabuckthorn leaf extract (ST) in extending the shelf life of peach fruits at refrigerated temperature. Peach fruits of ‘Elberta’ cultivar were coated with one of the following treatment combinations: distilled water (control), CHI (1.0%), CHI (1%) + ST (0.5%), CHI (1%) + ST (1.0%), CHI (1%) + ST (1.5%) and CHI (1%) + ST (2.0%) and then stored at 4 °C for 25 days. The combined treatment of CHI and ST showed a synergistic effect in significantly decreasing the skin browning and maintaining the firmness during the storage period, corroborated by the decline in the polyphenol oxidase, cellulase and pectinase enzyme activity. In particular, fruits treated with CHI (1%) + ST (1.5%) and CHI (1%) + ST (2.0%) showed maximum efficiency in retaining the physico-chemical attributes, increasing the antioxidant potential and controlling the browning during post harvest period upto 25 days under refrigerated temperature at 4 °C. Furthermore, besides maintaining the quality parameters, the treated fruits showed a significant reduction in microbial spoilage and maintaining the acceptable sensory attributes. Therefore, the study employing the incorporation of Seabuckthorn leaf extract into chitosan edible coating could be a valuable addition and promising approach to different existing preservation techniques towards extending the shelf life of peach fruits.