Ammonia-lyase Enzyme Research Articles

Arbuscular mycorrhizal fungi improve growth, essential oil, secondary metabolism, and yield of tobacco (Nicotiana tabacum L.) under drought stress conditions.

Drought is a major environmental threat limiting worldwide crop production. Drought stress affects the tobacco quality and yield; therefore, the current research studies were undertaken to investigate the effectiveness of arbuscular mycorrhizal fungi (AMF) under drought stress on morphological and biochemical attributes of tobacco (Nicotiana tabacum L. variety Yunyan 87). AMF-inoculated and AMF-non-inoculated plants were maintained in a greenhouse and irrigated with a half-strength Hoagland solution (100 mL pot-1) once a week. At harvesting, the plant height, number of leaves, fresh and dry weights, mycorrhizal colonization, and concentration of leaf photosynthetic pigments and photosynthetic rate were measured. Data were statistically analyzed by ANOVA and the principal component (PCA) analyses. The effect of root colonization significantly increased biomass production and essential oil accumulation. Results showed that drought at mild and severe stressed levels significantly affected tobacco growth by decreasing plant height, biomass, and a number of leaves. However, inoculation of AMF considerably increased plant height, fresh and dry weights, chlorophyll (a, b), total chlorophyll, and carotenoid content by 43.84, 40.87 and 49.76, 185.29, 325.60, 173.12, and 211.49%, respectively. Compared with non-inoculated plants, AMF inoculation significantly enhanced the essential oil yield and the uptake of nitrogen, phosphorus, and potassium with the increase of 257.36, 102.71, and 90.76, 62.32, and 84.51%, respectively, in mild drought + AMF-treated plants. Similarly, the antioxidant enzymatic activity, glomalin-related soil protein (GRSP), and accumulation of phenols and flavonoids and osmolytes content were also significantly improved in inoculated plants under drought stress. Additionally, AMF inoculation significantly upregulated the lipoxygenase (LOX) and phenylalanine ammonia-lyase (PAL) enzymes by 197 and 298.44% under drought conditions. These findings depicted that the symbiotic association of AMF improved the overall growth pattern and secondary metabolism in tobacco plants under severe drought stress conditions and may be used as an approaching source of important drugs in the field of pharmacology.

Combination of sodium alginate-based coating with L-cysteine and citric acid extends the shelf-life of fresh-cut lotus root slices by inhibiting browning and microbial growth

The effects of a sodium alginate (SA) coating combined withl-cysteine (L-cys) and citric acid (CA) on browning and microbial growth in fresh-cut lotus root slices during storage at 4 °C were investigated. The SA + L-cys + CA treatment was more efficient than separate SA andl-cys + CA treatments in the maintenance of visual appearance and flavour quality. The SA + L-cys + CA coating improved the ability of antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) to scavenge reactive oxygen species, including O2·− and H2O2. In comparison to the control, the SA + L-cys + CA treatment lowered the activity of phenylalanine ammonia lyase, peroxidase, and membrane lipid-degrading enzymes (phospholipase D, lipase and lipoxygenase) and furthermore, maintained high amounts of unsaturated and saturated fatty acids as well as low levels of phenolics and malondialdehyde. The bacterial diversity in lotus root slices was also determined and discussed. The SA + L-cys + CA treatment could maintain the shelf-life of fresh-cut lotus root slices for 14 d at 4 °C, which provides a theoretical basis for commercial application.

Use of elicitors and fungicides for the postharvest management of Monilinia fructicola in peach

Abstract The aim of this research was to study the effect of two factors: elicitors and fungicide doses. The experiment was conducted in 2017 and 2018. The treatments were applied in four randomized complete blocks with six peach trees as the experimental unit. The effectiveness of treatments was evaluated after harvest so that fruits were inoculated with Monilinia fructicola and lesion diameter measurements were performed to evaluate the area under the disease progress curve (AUDPC) and determine the rate of increase. The content of total phenols and the activity of peroxidase, polyphenoloxidase, catalase and phenylalanine ammonia-lyase enzymes were evaluated. The results showed that applications of potassium phosphite combined with full fungicide doses reduced AUDPC of Monilinia fructicola by 47% compared with the control (no elicitor, no fungicide). The content of phenols and the enzymatic activity increased with the application of elicitors. Pre-harvest application of elicitors is a viable option for the postharvest management of Monilinia fructicola.

Evaluation of Host Plant Resistance to Meloidogyne incognita in Banana Hybrids

The reaction of twenty four new synthetic banana hybrids were selected and evaluated for resistance to M. incognita under artificially inoculated pot conditions. Known susceptible (Grand Naine) and resistant (Yankambi KM5) banana varieties were included as reference cultivars. Responses of banana hybrids to M. incognita infection was assessed by the nematodes population in roots, number of galled roots, percentage of galled roots and root gall index on a scale of 1-5, where 0 = 0 galls and 5≥100 galls. The result showed that seven banana hybrids, H 904, H 911, H 921, H 924, H 926, H 943 and H 952 were found to be tolerance to M. incognita and the remaining were rated as moderate susceptible and susceptible. The total phenols, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase chemical and enzyme contains in roots were higher in tolerance genotypes viz-a-vis susceptible ones.

Changes in the physiological and biochemical state of peanut plants (Arachis hypogaea L.) induced by exposure to green metallic nanoparticles

Different types of nanoparticles (NPs) are increasingly used in multiple sectors such as industry, medicine and agriculture. This application has increased the possibility of NPs accumulating and contaminating the environment. Plants are one of the essential building blocks of all ecosystems and the interaction between NPs and plants is an indispensable aspect of risk assessment. To understand the effects of NPs in agricultural systems, in the present study we investigated the effects of exposure of Ag, Cu and Cu/Ag phytonanoparticles in Arachis hypogaea L. plants at a physiological and biochemical level, for which NPs solutions were applied foliarly at concentrations of 250, 500, 750 and 1000 ppm for 48 days. Parameters such as leaf length, chlorophyll and concentration of phytohormones showed that phytonanoparticles could cause serious damage to plant growth and development. Plants exposed to phytonanoparticles showed an increase in total phenols, proline, PAL activity and antioxidant enzymes, this to mitigate the stress caused. The alteration in the composition and content of fatty acids in the peanut kernels after exposure to different NPs indicated that they could affect the yield and quality of crop. Therefore, it is necessary to investigate its potential impact on food quality. Statement of novelty In this manuscript, we report for the first time that green nanoparticles induced a lower degree of toxicity in plants compared to commercial nanoparticles. Our results indicate that the mechanisms by which peanut plants respond to the application of nanoparticles were an increase in the activity of phenylalanine ammonia-lyase and antioxidant enzymes. So far there are few studies on the effect of nanoparticles on plant hormones, our results revealed a significant decrease in indole-3 acetic acid and induced the synthesis of gibberellins. The modification in the composition and content of fatty acids in the peanut kernels indicated that the nanoparticles could affect the quality of the crop.

Phenylalanine Alleviates Postharvest Chilling Injury of Plum Fruit by Modulating Antioxidant System and Enhancing the Accumulation of Phenolic Compound

SUMMARYResearch backgroundLow temperature storage causes chilling injury in plum (Prunus domestica L.) fruits. Consequently, any treatments with beneficial effects against these symptoms would achieve attention. For this purpose, phenylalanine treatments were applied on ‘Stanley’ plum fruits. The main purpose of the present study is to investigate the influence of the exogenous application of phenylalanine on fruit quality, chilling tolerance, and antioxidant capacity of ‘Stanley’ plums during cold storage.Experimental approachPhenylalanine at different concentrations was applied on ‘Stanley’ plums. Following phenylalanine application, plums were cold stored. Chilling injury, antioxidant capacity, electrolyte leakage, malondialdehyde, proline and internal contents of anthocyanin, flavonoids, phenols, ascorbic acid and some antioxidant enzymes were assessed.Results and conclusionsPhenylalanine treatment significantly alleviated chilling injury in plum fruits by enhancing antioxidant capacity and increasing the activity of phenylalanine ammonia lyase enzyme (PAL). Phenylalanine-treated fruits had higher mass fractions of ascorbic acid, anthocyanins, flavonoids and phenols, as well as a higher total antioxidant activity than the control fruits during low temperature storage. Phenylalanine at 7.5 mM was the most effective treatment in enhancing the activity of PAL, the accumulation of phenolic compounds and in reducing the severity of chilling injury. Treatments delayed mass loss and maintained fruit firmness. In addition, the application of 7.5 mM phenylalanine improved the activities of antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase), decreased the accumulation of hydrogen peroxide, and increased the endogenous content of proline. Moreover, phenylalanine maintained membrane integrity, manifested by a reduced electrolyte leakage and malondialdehyde accumulation.Novelty and scientific contributionIn the current study, chilling injury had a positive correlation with the activities of PAL and antioxidant enzymes. However, negative correlations were observed between the chilling injury and ascorbic acid mass fraction, and antioxidant capacity. Considering the results, phenylalanine treatment could be an encouraging approach to alleviate the severity of chilling injury and thus preserve nutritional quality of plums during low temperature storage.

Management of blue mold (Penicillium italicum) on mandarin fruit with a combination of the yeast, Meyerozyma guilliermondii and an alginate oligosaccharide

The ability of an antagonistic yeast Meyerozyma guilliermondii and an alginate oligosaccharide (AOS), a bio-active compound extracted from brown algae, to control postharvest blue mold and natural infection on mandarin fruit was evaluated. Results indicated that M. guilliermondii and AOS as individual treatments, significantly inhibited blue mold development and natural decay occurrence on mandarin fruit, compared to the untreated, control fruit. The combination of both M. guilliermondii and AOS, however, provided better control than either treatment alone. M. guilliermondii growth in mandarin wounds was not affected by AOS. Further analysis indicated that M. guilliermondii and AOS individually or in combination elevated peroxidase and phenylalanine ammonia-lyase enzyme activity, as well as total phenolics in mandarin fruit. The ability of AOS to improve the biocontrol efficacy of M. guilliermondii may be partially attributed to defense response induction in mandarin fruit. AOS also reduce water loss in mandarin fruit. Collectively, the data indicated that the combined application of M. guilliermondii and AOS represents an effective method of postharvest disease management in citrus fruit.

Monitoring of the PAL Enzymatic Activity and Polyphenolic Compounds in Leaves and Fruits of Two Myrtle Cultivars during Maturation

The leaves and berries of myrtle (Myrtus communis L.) are rich in phenolic compounds, such as phenolic acids, flavonoids, and flavanols. The richness of these antioxidant compounds allows the potential use of myrtle biomasses as raw materials for medicinal and functional food products. Most of the phenolic compounds originate from the phenylpropanoid pathway, where phenylalanine ammonia lyase (PAL) enzyme activates the first step. The objective of this research is to study the activity of PAL as related to accumulation in the myrtle fruits and leaves of some phenolic compounds in the period between blossom and full berry ripening. With this aim, we compared two model genotypes with different fruit coloration. In leaves and berries of two cultivars, ‘Giovanna’ with pigmented berries and ‘Grazia’ with white berries, the PAL activity and content of polyphenols, anthocyanins, flavonoids, and tannins were determined with spectrophotometric methods. PAL activity was quite constant in leaves and variable in berries: Greater in berries of ‘Giovanna’ than in those of ‘Grazia’ cultivar, and increasing from berry color-break to full ripening. In berries, a positive correlation between PAL and flavonoids (r = 0.44), and between PAL and anthocyanins (r = 0.69), as well as a negative correlation between PAL and total polyphenols (r = −0.471), were found.

Influence of Seed Biopriming and Vermiwash Treatment on Tomato Plant's Immunity and Nutritional Quality upon Sclerotium rolfsii Challenge Inoculation

Tomato is an important nutritional vegetable crop and its nutrient contents are affected by both biotic and abiotic stresses. The main objective of this study was to determine the effect of seed biopriming with Trichoderma pseudokoningii BHUR2 and vermiwash treatment on nutrient content of tomato and defense response against Sclerotium rolfsii under heat stress condition. The combined application of T. pseudokoningii BHUR2 and vermiwash increased fresh weight of root (4.8-fold) and shoot (5.8-fold), dry weight of root (6.9-fold) and shoot (6.4-fold) and number of fruits per plant (4.2-fold) as compared to control under S. rolfsii inoculated condition. Plants treated with T. pseudokoningii BHUR2 and vermiwash exhibited higher defense response against S. rolfsii, mediated by higher activity of superoxide dismutase (3.57-fold), peroxidase (2.05-fold) and phenylalanine ammonia lyase (2.98-fold) enzymes and accumulation of total phenol content (5.35-fold) as compared to control plants. In addition, combined treatment was found to have a positive impact on nutritional status (N, P, K and Ca and lycopene, total soluble sugar and total protein) in tomato fruit. These results suggest potential of T. pseudokoningii BHUR2 and vermiwash in enhancing tomato immunity against S. rolfsii under heat stress condition, which was due to (1) induction in the antioxidant activity and phenylpropanoid pathway, which minimize oxidative damage and reduce pathogen infection and (2) significant improvement in nutrient content leads to better plant growth. The formulation of Trichoderma BHUR2 can be used for field application to mitigate heat stress in plants.

Toward a Scalable Synthesis and Process for EMA401, Part III: Using an Engineered Phenylalanine Ammonia Lyase Enzyme to Synthesize a Non-natural Phenylalanine Derivative

A process using an engineered phenylalanine ammonia lyase (PAL) enzyme was developed as part of an alternative route to a key intermediate of olodanrigan (EMA401). In the first part of this report,...

Türkiye'deki Bazı Doğa ve Kültürü Yapılan Yenebilir Mantarların Antioksidan Enzim Aktiviteleri

In this study; wild and cultivated edible mushrooms [Boletus edulis Bull.: Fr, Craterellus cornucopioides (L.) Pers., Lactarius deliciosus (L. ex Fr.) S.F.Gray, Laetiporus sulphureus (Bull.: Fr.) Murr., Marasmius oreades (Bolt. ex Fr.) Fr., Morchella conica Pers., Ramaria botrytis (Pers.: Fr.) Ricken, Tricholoma terreum (Schaeff.: Fr.) P. Kumm., Hericium erinaceus (Bull.: Fr.) Pers., Lentinula edodes (Berk.) Pegler, Ganoderma lucidum (Curt.: Fr.) P. Karst., and Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm. (1-4)] were obtained from different locations in Turkey. Phenylalanine ammonia lyase (PAL) enzyme activity, ascorbate peroxidase (APX), peroxidase (POD), and superoxide dismutase (SOD) activity changes and nitrate, β-carotene and lycopene levels were investigated in 15 samples to determine antioxidant enzyme capacity. As a result of the study, the highest amount of β-carotene and lycopene were determined in H. erinaceus. P. ostreatus-2 had the lowest amount of β-carotene, whereas Pleurotus ostreatus-1 had the lowest amount of lycopene. Species rich in nitrate content were C. cornucopioides and P. ostreatus-4. P. ostreatus-3 was the poorest species in terms of nitrate compared to other mushroom samples. PAL activity of mushrooms varied between 5.863 and 8.893 EU mg-1 protein. For APX values, P. ostreatus-4 had the highest value, while H. erinaceus species had the lowest value. Among mushroom species, the highest and the lowest POD values were determined in H. erinaceus and B. edulis, respectively. C. cornucopioides had the highest and P. ostreatus-3 had the lowest SOD values.

Melatonin and calcium modulate the production of rosmarinic acid, luteolin, and apigenin in Dracocephalum kotschyi under salinity stress

Melatonin (Mel) and calcium (Ca2+) have a regulatory role in the induction of specialized metabolites production and defensive responses against stresses. Therefore, in this study, the effects of Mel and Ca2+ and the possible relationship between them in the increase of the production of phenolic compounds in Dracocephalum kotschyi Boiss. under both control and salinity stress conditions were investigated. The results showed that 75 mM NaCl reduced shoot dry biomass but elevated H2O2 content, electrolyte leakage (EL) level, total phenolic and flavonoid contents (TPC and TFC), and DPPH scavenging capacity. Salinity stress also upregulated gene expression of phenylalanine ammonia-lyase (PAL) and rosmarinic acid synthase (RAS), as well as the activities of PAL and tyrosine ammonia-lyase (TAL) enzymes. Pre-treatment of the plants with CaCl2 and Mel affected these attributes in a dose-dependent manner. Application of 5 mM Ca2+ and 100 μM Mel improved shoot dry biomass and reduced the level of EL and H2O2 content but enhanced TPC and TFC, DPPH scavenging capacity, PAL and TAL activities, PAL and RAS transcripts, and content of rosmarinic acid (RA), luteolin flavone (LF) and apigenin flavone (AF) under salinity stress. Pre-treatment of D. kotschyi with lanthanum chloride (LaCl3) as a plasma membrane channel blocker, ethylene glycol tetra-acetic acid (EGTA) as a Ca2+ chelator and trifluoperazine (TFP) as a calmodulin (CaM) antagonist, impaired Mel effects on the above attributes under salinity stress. In contrast, pre-treatment with p–chlorophenylalanine (p-CPA), as an inhibitor of Mel biosynthesis, did not impair the impacts of Ca2+ on the production of phenolic compounds in salt-exposed plants. These results suggested that the effect of Mel on the induction of phenolic compounds production requires the influx of extracellular Ca2+ into the cells and is dependent on Ca2+/CaM signaling.

Chitosan associated with chelated copper applied on tomatoes: enzymatic and anatomical changes related to plant defense responses

The aim of this work was study the use of an experimental product containing chitosan and chelated cooper (Cu) as a sustainable tool for the protection of tomato plants, to understand which are the mechanisms involved in resistance promotion and what could be the anatomical changes on tomato leaves related to those defense responses. The experiment was conducted in a greenhouse with tomato plants grown in pots and subjected to weekly foliar sprays of a suspension containing chitosan associated with Cu-EDTA (ChiCu). The increase in the phenolic compound concentrations and phenylalanine ammonia-lyase (PAL) enzyme activities were detected 24 hours after. In addition, an increase was observed in the activity of chitinase and β-1,3-glucanase, enzymes related to defense responses. Also, an increase was found in the thickness of the outer periclinal wall on the adaxial epidermal surface in leaves submitted to 4 ml L-1 ChiCu. The proportion of the epiderm to the leaf blade was also higher. Although the pathogenicity-related enzymes were activated as well as phenolic compounds were increased, these changes did not affected the biometric and biochemical parameters related to the primary metabolism and essential for the maintenance of productive potential of tomato plants. The increase in the outer periclinal wall as a result of ChiCu sprays could have contributed to the resistance against diseases since it is the first barrier to the infection of a wide of pathogens.

Crystal structure of histidine ammonia-lyase from Trypanosoma cruzi

Chagas disease is one of seventeen neglected tropical diseases according to the World Health Organization (WHO). The histidine-glutamate metabolic pathway is an oxidative route that has shown to be relevant for the bioenergetics in Trypanosoma cruzi, the etiological agent for Chagas disease. Histidine ammonia-lyase participates in the first stage of the histidine catabolism, catalyzing the conversion of l-histidine into urocanate. This work presents the three-dimensional (3D) structure of Trypanosoma cruzi histidine ammonia-lyase enzyme (TcHAL) and some comparisons of it to homologous structures. The enzyme was expressed, purified and assayed for crystallization, what allowed the obtainment of crystals of sufficient quality to collect X-ray diffraction data up to 2.55 Å resolution. After refinement, some structural analyses indicated that the structure does not contain the active site protection domain, in opposition to previously known 3D structures from plants and fungi phenylalanine ammonia-lyase, therefore, it is the first structure of eukaryotic ammonia-lyases that lacks this domain.

The studies on the morphological variability and biochemical changes induced by Mungbean Yellow Mosaic Virus (MYMV) in mungbean [Vigna radiata (L.) Wilczek

In the present investigation eighteen mungbean [Vigna radiata (L.) Wilczek] genotypes were screened against MYMV disease under field conditions and identified that the three genotypes as resistant, six as moderately resistant, four genotypes as moderately susceptible, three as susceptible and two as highly susceptible genotypes based on modified MULLaRP disease incidence scale (0–9). Morphological characters viz., leaf thickness and trichome density was evaluated among the genotypes having different degree of resistance. It was observed that leaves of MYMV resistant genotypes were thicker when compared to highly susceptible genotypes. Similarly, trichome density in resistant genotypes were comparatively high to that of highly susceptible genotypes. The biochemical contents viz., total phenol content, total sugar content and chlorophyll content and enzyme activity of peroxidase (PO), polyphenol oxidase (PPO) and Phenylnine ammonia lyase (PAL) enzyme activity was studied both at 30 and 60 Days after sowing (DAS). The phenol content was found higher in resistant genotypes followed by moderately resistant, moderately susceptible, susceptible and highly susceptible at 30 and 60 DAS. The similar trend was also observed in case of total phenol, chlorophyll content and peroxidase, polyphenol oxidase and Phenylnine ammonia lyase enzyme activity.

Selenium nanoparticles induced variations in growth, morphology, anatomy, biochemistry, gene expression, and epigenetic DNA methylation in Capsicum annuum; an in vitro study

This study aimed to explore whether supplementation of the culture medium with selenium nanoparticles (nSe) can influence growth, biochemistry, expression of transcription factors, and epigenetic DNA methylation in Capsicum annuum. The seeds were grown in hormone-free MS culture medium supplemented with nSe (0, 0.5, 1, 10, and 30 mgL−1) or corresponding doses of bulk type selenate (BSe). Incorporation of nSe into the medium caused variations in morphology and growth in a manner dependent on the dose and Se type. The low doses of nSe displayed growth-promoting effects, whereas nSe at 10 and 30 mgL−1 were associated with severe toxicity and abnormality in leaf and root development. MSAP analysis confirmed the substantial variation in cytosine DNA methylation in response to the toxic dose of nSe exhibiting epigenetic modification. The nSe toxicity was associated with DNA hyper-methylations. The nSe treatments transcriptionally upregulated the bZIP1 transcription factor by an average of 3.5 folds. With a similar trend, the upregulation (mean = 9.8 folds) in the expression of the WRKY1 transcription factor resulted from the nSe application. The nSe0.5 or nSe1 treatments resulted in a significant induction (mean = 48%) in nitrate reductase activity. A high dose of nSe led to an increase in proline concentration. The nSe treatments were also associated with modifications in activities of peroxidase and catalase enzymes. Besides, the nSe utilization increased the activity of phenylalanine ammonia-lyase enzyme (mean = 76%) and concentrations of soluble phenols (mean = 51%). The toxic dose of nSe also caused abnormalities in the structure of the stem apical meristem. The nSe toxicity was also associated with inhibition in the differentiation of xylem tissues. These findings provide novel insights into the nSe-associated molecular variations in conferring the modified growth, anatomy, and metabolism.

LED light mediates phenolic accumulation and enhances antioxidant activity in Melissa officinalis L. under drought stress condition.

The popularity of lemon balm in conventional medicine is suggested by the existence of two groups of compounds, namely essential oil and phenylpropanoids pathway derivatives. One of the promising approaches to improve tolerance to drought stress inducedoxidative damage in seedlings grownin greenhouses and plant growth chambers is replacing the traditional and high-cost light technologies by recently developed light emitting diodes (LED). In this experiment, we analyzed the role of various LED lights including red (R), blue (B), red (70%) + blue (30%) (RB), and white (W) as well as normalgreenhouse light(as control) to stimulate defense mechanisms against drought stress in two genotypes of Melissa officinalis L. The present study demonstrates that pre-treatment with LEDs with high-intensity output for 4weeks alleviated harmful effects of drought stress in the two genotypes. Under drought stress, RB LED pre-treated plantlets of the two genotypes exhibited the highest relative growth index of shoot and root and total phenolic and anthocyanin content compared to those irradiated with other LEDs and greenhouse lights. The highest amount of malondialdehyde level was detected in R LED exposed plants. In response to drought, LED-exposed plants especially RB light-irradiated plants of the two genotypes maintained significantly higher antioxidant and phenylalanine ammonia-lyase (PAL) enzyme activities and higherexpression level of the PAL1 and 4CL-1 genes compared to those irradiated with greenhouse light. We concluded that RB LED light provides a better growthcondition and resistance to drought stress for the two genotypes of lemon balm by the highest antioxidant activity and the least amount of damage to the cell membranes. Our data suggest that LED light pre-treatments as moderate stress activate antioxidant systems, enhance the scavenging of ROS and induce drought stress tolerance in the two genotypes of lemon balm plants.

Study of the Potential of the Capsule Shell Based on Natural Polysaccharides in Targeted Delivery of the L-Phenylalanine Ammonia-Lyase Enzyme Preparation.

The treatment of classical phenylketonuria is currently represented by many new methods of disease management. A promising method is the use of the enzyme L-phenylalanine ammonia-lyase (PAL) in various forms. The widespread use of enzyme preparations in therapy is limited by a lack of understanding of the mechanisms and systems of the targeted transport of PAL into certain organs and tissues as a result of the incorporation of a drug into the carrier. To ensure the stability of enzymes during the delivery process, encapsulation is preferable, which, as a rule, ensures the preservation of the qualitative characteristics of the enzymes orally applied to the environmental effects of the gastrointestinal tract (acidity, temperature, oxidation, etc.). Capsule preparations showed sufficient stability in the model gastric fluids and sustained release of the drug in the simulated intestinal fluid. Currently, there is a wide range of polymers used for encapsulation. The use of natural sources in the production technology of capsule systems improves bioavailability, controls the release, and prolongs the half-life of active substances. The advantage of this method is that the used enzyme is completely protected by the cell membranes of the capsules, which preserve its stability in the aggressive environment of the gastrointestinal tract. Capsules were obtained on the basis of compositions of hydrocolloids of plant origin. The potential of the developed capsules for targeted delivery of the enzyme preparation was studied. The degradation of the encapsulated form of the PAL enzyme preparation was studied in vitro in model bio-relevant media simulating the gastric and intestinal environment. The dynamics of the breakdown of the capsule shell allow us to expect that the release of L-phenylalanine ammonia-lyase from capsules based on plant hydrocolloids will occur no earlier than reaching the upper intestines, where the interaction with the protein components of the consumed food products to neutralize phenylalanine should occur.

Cold stress changes antioxidant defense system, phenylpropanoid contents and expression of genes involved in their biosynthesis in Ocimum basilicum L.

Environmental stresses might alter the activity of antioxidant defense system and both quantity and quality of the essential oil constituents in aromatic plants. In the current study, a greenhouse experiment was designed to assess the influence of cold stress on total phenolic (TPC) and flavonoid contents (TFC), DPPH radical scavenging, antioxidant and phenylalanine ammonia-lyase (PAL) enzymes activity and content of phenylpropanoid compounds in Ocimum basilicum L. The genes expression levels of chavicol O-methyl transferase (CVOMT), cinnamate 4-hydroxylase (C4H), eugenol synthase 1 (EGS1) and eugenol O-methyl transferase (EOMT) were also investigated. Results revealed the highest TPC, TFC and DPPH at 4 °C for 12 h. Positive significant correlation was observed between TFC and DPPH, as well as TPC and PAL enzyme activity. The highest activity of superoxide dismutase and guaiacol peroxidase was recorded in 4 °C for 48 h, while this treatment caused the highest reduction in the activities of ascorbate peroxidase and catalase. In plants exposed to 10 °C for 48 h, the contents of methyleugenol and methylchavicol was positively associated with the expression levels of EGS1 and EOMT. A positive correlation was also found between C4H expression and eugenol, methyleugenol and methylchavicol contents under 4 °C for 12 h.

Does compatibility of wheat cultivars with Azospirillum brasilense strains affect drought tolerance?

Due to various physiological outcomes from different symbiosis combinations of wheat cultivars (Triticum aestivum L.) with Azospirillum brasilense strains, evaluation of compatibility of wheat cultivars with bacteria strains is essential to assess the improvement of wheat tolerance to drought condition. So, under control condition (80% of field capacity), the rate of compatibility of six wheat cultivars inoculated with A. brasilense Sp7 (as standard) or Sp245 (produce more abscisic acid) strains was determined based on the growth and biochemical parameters. According to the result Roshan-Sp245, Shahpasand-Sp7, Roshan-Sp7, and Shahpasand-Sp245 as the most compatible, most incompatible, less compatible and less incompatible were determined, respectively. In another experiment, selected combinations were compared at drought condition (40% of field capacity). All physiological parameters were significantly (P ≤ 0.05) affected due to compatibility or drought conditions. In average, under drought condition, root lengths affected positively in Roshan (tolerant) and negatively in Shahpasand (sensitive) cultivars inoculated with different strains of bacteria. Although, shoots protein significantly correlated with compatibility (r = 0.94), number of root branches correlated more with drought tolerance (r = 0.98). In Roshan-Sp245 as compatible pair, enzyme activity of TAL (tyrosine ammonia lyase) in roots, number of root branches, root’s protein, shoot’s PAL (phenylalanine ammonia lyase enzyme) and TAL activities were increased. In contrast, in Shahpasand-Sp7 as incompatible pair, these parameters decreased or did not change under drought condition. Therefore, higher tolerance to drought was obtained through the compatibility of associated pairs. However, significant correlation between compatibility, drought tolerance (r = 0.77) and different parameters were observed.