Aspergillus welwitschiae BK Isolate Ameliorates the Physicochemical Characteristics and Mineral Profile of Maize under Salt Stress

Abiotic stressors are global limiting constraints for plant growth and development. The most severe abiotic factor for plant growth suppression is salt. Among many field crops, maize is more vulnerable to salt, which inhibits the growth and development of plants and results in low productivity or even crop loss under extreme salinity. Consequently, comprehending the effects of salt stress on maize crop improvement, while retaining high productivity and applying mitigation strategies, is essential for achieving the long-term objective of sustainable food security. This study aimed to exploit the endophytic fungal microbe; Aspergillus welwitschiae BK isolate for the growth promotion of maize under severe salinity stress. Current findings showed that salt stress (200 mM) negatively affected chlorophyll a and b, total chlorophyll, and endogenous IAA, with enhanced values of chlorophyll a/b ratio, carotenoids, total protein, total sugars, total lipids, secondary metabolites (phenol, flavonoids, tannins), antioxidant enzyme activity (catalase, ascorbate peroxidase), proline content, and lipid peroxidation in maize plants. However, BK inoculation reversed the negative impact of salt stress by rebalancing the chlorophyll a/b ratio, carotenoids, total protein, total sugars, total lipids, secondary metabolites (phenol, flavonoids, tannins), antioxidant enzyme activity (catalase, ascorbate peroxidase), and proline content to optimal levels suitable for growth promotion and ameliorating salt stress in maize plants. Furthermore, maize plants inoculated with BK under salt stress had lower Na⁺, Cl^- concentrations, lower Na^+/K⁺ and Na⁺/Ca²⁺ ratios, and higher N, P, Ca²⁺, K⁺, and Mg²⁺ content than non-inoculated plants. The BK isolate improved the salt tolerance by modulating physiochemical attributes, and the root-to-shoot translocation of ions and mineral elements, thereby rebalancing the Na⁺/K⁺, Na⁺/Ca²⁺ ratio of maize plants under salt stress.

Arginase 1 expression is increased during hepatic stellate cell activation and facilitates collagen synthesis

Activation of hepatic stellate cells (HSC) is a key event in the initiation of liver fibrosis. Activated HSCs proliferate and secrete excessive amounts of extracellular matrix (ECM), disturbing liver architecture and function, leading to fibrosis and eventually cirrhosis. Collagen is the most abundant constituent of ECM and proline is the most abundant amino acid of collagen. Arginine is the precursor in the biosynthetic pathway of proline. Arginine is the exclusive substrate of both nitric oxide synthase (NOS) and arginase. NOS is an M1 (proinflammatory) marker of macrophage polarization whereas arginase-1 (Arg1) is an M2 (profibrogenic) marker of macrophage polarization. Differential expression of NOS and Arg1 has not been studied in HSCs yet. To identify the expression profile of arginine catabolic enzymes during HSC activation and to investigate their role in HSC activation, primary rat HSCs were cultured-activated for 7 days and expression of iNOS and Arg1 were investigated. Nor-NOHA was used as a specific and reversible arginase inhibitor. During HSC activation, iNOS expression decreased whereas Arg1 expression increased. Inhibition of Arg1 in activated HSCs efficiently inhibited collagen production but not cell proliferation. HSC activation is accompanied by a switch of arginine catabolism from iNOS to Arg1. Inhibition of Arg1 decreases collagen synthesis. Therefore, we conclude that Arg1 can be a therapeutic target for the inhibition of liver fibrogenesis.

Collagen-Derived Dipeptides and Amino Acids Have Immunomodulatory Effects in M1-Differentiated RAW264.7 Cells and PBMC

A number of food components, such as polyphenols and phytonutrients, have immunomodulatory effects. Collagen has various bioactivities, such as antioxidative effects, the promotion of wound healing, and relieving symptoms of bone/joint disease. Collagen is digested into dipeptides and amino acids in the gastrointestinal tract and subsequently absorbed. However, the difference in immunomodulatory effects between collagen-derived dipeptides and amino acids is unknown. To investigate such differences, we incubated M1 macrophages or peripheral blood mononuclear cells (PBMC) with collagen-derived dipeptides (hydroxyproline-glycine (Hyp-Gly) and proline-hydroxyproline (Pro-Hyp)) and amino acids (proline (Pro), hydroxyproline (Hyp), and glycine (Gly)). We first investigated the dose dependency of Hyp-Gly on cytokine secretion. Hyp-Gly modulates cytokine secretion from M1 macrophages at 100 µM, but not at 10 µM and 1 µM. We then compared immunomodulatory effects between dipeptides and mixtures of amino acids on M1 macrophages and PBMC. There was, however, no difference in cytokine secretion between dipeptides and their respective amino acids. We conclude that collagen-derived dipeptides and amino acids have immunomodulatory effects on M1-differentiated RAW264.7 cells and PBMC and that there is no difference in the immunomodulatory effects between dipeptides and amino acids.

Does Potassium Modify the Response of Zinnia (Zinnia elegans Jacq.) to Long-Term Salinity?

Salinity is one of the major abiotic stress factors hindering crop production, including ornamental flowering plants. The present study examined the response to salt stress of Zinnia elegans 'Lilliput' supplemented with basic (150 mg·dm^-3) and enhanced (300 mg·dm^-3) potassium doses. Stress was imposed by adding 0.96 and 1.98 g of NaCl per dm^-3 of the substrate. The substrate's electrical conductivity was 1.1 and 2.3 dS·m^-1 for lower potassium levels and 1.2 and 2.4 dS·m^-1 for higher potassium levels. Salt stress caused a significant and dose-dependent reduction in leaf RWC, increased foliar Na and Cl concentrations, and reduced K. About 15% and 25% of cell membrane injury at lower and higher NaCl doses, respectively, were accompanied by only slight chlorophyll reduction. Salt stress-induced proline increase was accompanied by increased P5CS activity and decreased PDH activity. More than a 25% reduction in most growth parameters at EC 1.1-1.2 dS·m^-1 but only a slight decrease in chlorophyll and a 25% reduction in the decorative value (number of flowers produced, flower diameter) only at EC 2.3-2.4 dS·m^-1 were found. Salt stress-induced leaf area reduction was accompanied by increased cell wall lignification. An enhanced potassium dose caused a reduction in leaf Na and Cl concentrations and a slight increase in K. It was also effective in membrane injury reduction and proline accumulation. Increasing the dose of potassium did not improve growth and flowering parameters but affected the lignification of the leaf cell walls, which may have resulted in growth retardation. Zinnia elegans 'Lilliput' may be considered sensitive to long-term salt stress.

Priming Potato Plants with Melatonin Protects Stolon Formation under Delayed Salt Stress by Maintaining the Photochemical Function of Photosystem II, Ionic Homeostasis and Activating the Antioxidant System

Melatonin is among one of the promising agents able to protect agricultural plants from the adverse action of different stressors, including salinity. We aimed to investigate the effects of melatonin priming (0.1, 1.0 and 10 µM) on salt-stressed potato plants (125 mM NaCl), by studying the growth parameters, photochemical activity of photosystem II, water status, ion content and antioxidant system activity. Melatonin as a pleiotropic signaling molecule was found to decrease the negative effect of salt stress on stolon formation, tissue water content and ion status without a significant effect on the expression of Na⁺/H⁺-antiporter genes localized on the vacuolar (NHX1 to NHX3) and plasma membrane (SOS1). Melatonin effectively decreases the accumulation of lipid peroxidation products in potato leaves in the whole range of concentrations studied. A melatonin-induced dose-dependent increase in Fv/Fm together with a decrease in uncontrolled non-photochemical dissipation Y(NO) also indicates decreased oxidative damage. The observed protective ability of melatonin was unlikely due to its influence on antioxidant enzymes, since neither SOD nor peroxidase were activated by melatonin. Melatonin exerted positive effects on the accumulation of water-soluble low-molecular-weight antioxidants, proline and flavonoids, which could aid in decreasing oxidative stress. The most consistent positive effect was observed on the accumulation of carotenoids, which are well-known lipophilic antioxidants playing an important role in the protection of photosynthesis from oxidative damage. Finally, it is possible that melatonin accumulated during pretreatment could exert direct antioxidative effects due to the ROS scavenging activity of melatonin molecules.

Functional Dissection of the Physiological Traits Promoting Durum Wheat (Triticum durum Desf.) Tolerance to Drought Stress

In Tunisia's arid and semi-arid lands, drought stress remains the most critical factor limiting agricultural production due to low and irregular precipitation. The situation is even more difficult because of the scarcity of underground water for irrigation and the climate change that has intensified and expanded the aridity. One of the most efficient and sustainable approaches to mitigating drought stress is exploring genotypic variability to screen tolerant genotypes and identify useful tolerance traits. To this end, six Tunisian wheat genotypes (Triticum durum Desf.) were cultivated in the field, under a greenhouse and natural light, to be studied for their differential tolerance to drought stress. Many morpho-physiological and biochemical traits were analyzed, and interrelationships were established. Depending on the genotypes, drought stress significantly decreased plant growth, chlorophyll biosynthesis, and photosynthesis; stimulated osmolyte accumulation and disturbed water relations. The most tolerant genotypes (salim and karim) accumulated more potassium (K) and proline in their shoots, allowing them to maintain better tissue hydration and physiological functioning. The osmotic adjustment (OA), in which potassium and proline play a key role, determines wheat tolerance to drought stress. The calculated drought index (DI), drought susceptible index (DSI), drought tolerance index (DTI), K use efficiency (KUE), and water use efficiency (WUE) discriminated the studied genotypes and confirmed the relative tolerance of salim and karim.

Exogenous zinc mitigates salinity stress by stimulating proline metabolism in proso millet (Panicum miliaceum L.)

Salinity is one of the most concerning ecological restrictions influencing plant growth, which poses a devastating threat to global agriculture. Surplus quantities of ROS generated under stress conditions have negative effects on plants' growth and survival by damaging cellular components, including nucleic acids, lipids, proteins and carbohydrates. However, low levels of ROS are also necessary because of their role as signalling molecules in various development-related pathways. Plants possess sophisticated antioxidant systems for scavenging as well as regulating ROS levels to protect cells from damage. Proline is one such crucial non-enzymatic osmolyte of antioxidant machinery that functions in the reduction of stress. There has been extensive research on improving the tolerance, effectiveness, and protection of plants against stress, and to date, various substances have been used to mitigate the adverse effects of salt. In the present study Zinc (Zn) was applied to elucidate its effect on proline metabolism and stress-responsive mechanisms in proso millet. The results of our study indicate the negative impact on growth and development with increasing treatments of NaCl. However, the low doses of exogenous Zn proved beneficial in mitigating the effects of NaCl by improving morphological and biochemical features. In salt-treated plants, the low doses of Zn (1 mg/L, 2 mg/L) rescued the negative impact of salt (150mM) as evidenced by increase in shoot length (SL) by 7.26% and 25.5%, root length (RL) by 21.84% and 39.07% and membrane stability index (MSI) by 132.57% and 151.58% respectively.The proline content improved at all concentrations with maximum increase of 66.65% at 2 mg/L Zn. Similarly, the low doses of Zn also rescued the salt induced stress at 200mM NaCl. The enzymes related to proline biosynthesis were also improved at lower doses of Zn. In salt treated plants (150mM), Zn (1 mg/L, 2 mg/L) increased the activity of P5CS by 19.344% and 21%. The P5CR and OAT activities were also improved with maximum increase of 21.66% and 21.84% at 2 mg/L Zn respectively. Similarly, the low doses of Zn also increased the activities of P5CS, P5CR and OAT at 200mM NaCl. Whereas P5CDH enzyme activity showed a decrease of 82.5% at 2mg/L Zn+150mM NaCl and 56.7% at 2mg/L Zn+200 mM NaCl. These results strongly imply the modulatory role of Zn in maintaining of proline pool during NaCl stress.

Functional Quality, Antioxidant Capacity and Essential Oil Percentage in Different Mint Species Affected by Salinity Stress

Saline stress is responsible for significant reductions in the growth of plants, and it globally leads to limitations in the performance of crops, especially in drought-affected areas. However, a better understanding of the mechanisms involved in the resistance of plants to environmental stress can lead to a better plant breeding and selection of cultivars. Mint is one of the most important medicinal plants, and it has important properties for industry, and for the medicinal and pharmacy fields. The effects of salinity on the biochemical and enzymatic properties of 18 ecotypes of mint from six different species, that is, Mentha piperita, Mentha mozafariani, Mentha rotundifolia, Mentha spicata, Mentha pulegium and Mentha longifolia, have been examined in this study. The experimental results showed that salinity increased with increasing in stress integrity influenced the enzymatic properties, proline content, electrolyte leakage, and the hydrogen peroxide, malondialdehyde, and essential oil contents. Cluster analysis and principal component analysis were conducted, and they grouped the studied species on the basis of their biochemical characteristics. According to the obtained biplot results, M. piperita and M. rotundifolia showed better stress tolerance than the other varieties, and M. longifolia was identified as being salt sensitive. Generally, the results showed that H₂ O₂ and malondialdehyde had a positive connection with each other and showed a reverse relationship with all the enzymatic and non-enzymatic antioxidants. Finally, it was found that the M. spicata, M. rotundifolia and M. piperita ecotypes could be used for future breeding projects to improve the salinity tolerance of other ecotypes.

Effect of Hot- and Cold-Water Treatment on Broccoli Bioactive Compounds, Oxidative Stress Parameters and Biological Effects of Their Extracts

The goal of this work was to define resistant and susceptible variables of young broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) plants treated with cold and hot water. Additionally, we wanted to single out variables that could potentially be used as biomarkers of cold/hot-water stress in broccoli. Hot water changed more variables (72%) of young broccoli than cold water (24%) treatment. Hot water increased the concentration of vitamin C for 33%, hydrogen peroxide for 10%, malondialdehyde for 28%, and proline for 147%. Extracts of broccoli stressed with hot water were significantly more efficient in the inhibition of α-glucosidase (65.85 ± 4.85% compared to 52.00 ± 5.16% of control plants), while those of cold-water-stressed broccoli were more efficient in the inhibition of α-amylase (19.85 ± 2.70% compared to 13.26 ± 2.36% of control plants). Total glucosinolates and soluble sugars were affected by hot and cold water in an opposite way, which is why they could be used as biomarkers of hot/cold-water stress in broccoli. The possibility of using temperature stress to grow broccoli enriched with compounds of interest to human health should be further investigated.

Utilization of Response Surface Methodology in Optimization of Proline Extraction from Castanea sativa Honey

Proline constitutes approximately 85 % of the amino acid composition of honey. Therefore, the quantitative determination of this amino acid in honey samples is used by many national/international authorities to evaluate the quality of honey types. In this study, it was aimed to achieve maximum proline amino acid extraction from honey samples whose botanical origins were confirmed by melissopalynological analysis. For this reason, based on three different spectrophotometric methods used in the literature for proline analysis, proline extraction was optimized with the Response Surface Method (RSM) and Box-Behnken experimental design. Three independent variables were determined as treatment time (2, 6, and 10 min), treatment temperature (22, 46, and 70 °C), and cooling time (5, 25, and 45 min). As a result of the optimization, it was seen that only significantly effective independent variable on the proline content of honey was the processing temperature. The optimum conditions obtained as a result of the RSM were found to be 2 min for the treatment time, 70 °C for the treatment temperature and 45 min for the cooling time. The composite desirability of the optimum conditions (R² ) was found to be 1.00. It was determined that the method proposed by International Honey Commission (IHC) is efficient for proline analysis, but it provides more proline extraction by reducing of time from 10 min to 2 min in hold time in boiling water bath only during the extraction step. As a result, the conditions to be used in order to achieve maximum proline extraction with different spectrophotometric methods were determined and optimum values were determined. In addition, since the botanical origin of honey samples significantly affects the proline content of honey, it can be suggested that this study be optimized for different monofloral honey samples as well.

Targeting PYCR2 inhibits intraperitoneal metastatic tumors of mouse colorectal cancer in a proline-independent approach

Whether proline deficiency is a metabolic vulnerability in colorectal tumors is unknown. The aim of this study was to investigate the effects of proline metabolism-related genes and exogenous proline on the progression of colorectal cancer (CRC). We aimed to further clarify the role of pyrroline-5-carboxylate reductase (PYCR) 2, a key enzyme of proline synthesis, in the regulation of colorectal intraperitoneal metastatic tumors. This study was carried out based on The Cancer Genome Atlas (TCGA) data, database analysis, single-cell functional analysis, tissue microarray, cell experiments, and animal models. We found that, PYCR2 mRNA and protein levels were upregulated in CRC. The mRNA level of PYCR2 was closely related to the prognosis and tumor metastasis of CRC patients. The upregulated PYCR2 expression was at least partly due to low promoter methylation levels. The nomogram constructed based on PYCR2 expression and clinical characteristics of CRC showed good accuracy in predicting lymph node metastasis. Pycr2 knockdown inhibited epithelial-mesenchymal transition (EMT) of mouse CRC cells. Proline supplementation did not rescue the inhibition of mouse CRC cell proliferation and migration by Pycr2 knockdown. Proline supplementation also did not rescue the suppression of subcutaneous tumors and intraperitoneal metastatic tumors in mice by Pycr2 knockdown. PYCR2 co-expressed genes in TCGA-CRC were enriched in epigenetic modification-related biological processes and molecular functions. Four small molecules with the lowest binding energy to the PYCR2 protein were identified. Collectively, Pycr2 knockdown inhibited mouse CRC progression in a proline-independent approach. PYCR2 may be a promising tumor metastasis predictor and therapeutic target in CRC.

Recent Advances in Asymmetric Synthesis of Pyrrolidine-Based Organocatalysts and Their Application: A 15-Year Update

In 1971, chemists from Hoffmann-La Roche and Schering AG independently discovered a new asymmetric intramolecular aldol reaction catalyzed by the natural amino acid proline, a transformation now known as the Hajos-Parrish-Eder-Sauer-Wiechert reaction. These remarkable results remained forgotten until List and Barbas reported in 2000 that L-proline was also able to catalyze intermolecular aldol reactions with non-negligible enantioselectivities. In the same year, MacMillan reported on asymmetric Diels-Alder cycloadditions which were efficiently catalyzed by imidazolidinones deriving from natural amino acids. These two seminal reports marked the birth of modern asymmetric organocatalysis. A further important breakthrough in this field happened in 2005, when Jørgensen and Hayashi independently proposed the use of diarylprolinol silyl ethers for the asymmetric functionalization of aldehydes. During the last 20 years, asymmetric organocatalysis has emerged as a very powerful tool for the facile construction of complex molecular architectures. Along the way, a deeper knowledge of organocatalytic reaction mechanisms has been acquired, allowing for the fine-tuning of the structures of privileged catalysts or proposing completely new molecular entities that are able to efficiently catalyze these transformations. This review highlights the most recent advances in the asymmetric synthesis of organocatalysts deriving from or related to proline, starting from 2008.

Differentiation of advanced generation mutant wheat lines: Conventional techniques versus Raman spectroscopy

This research aimed to assess the feasibility of utilizing Raman spectroscopy in plant breeding programs. For this purpose, the evaluation of the mutant populations set up the application of 4 mM NaN₃ to the somatic embryos obtained from mature wheat (Triticum aestivum L. Adana-99 cv.) embryos. Advanced wheat mutant lines, which were brought up to the seventh generation with salt stress tolerance by following in vitro and in vivo environments constructed by mutated populations, were evaluated using conventional techniques [measurement of antioxidant enzyme activities (SOD, CAT, and POX), total chlorophyll, TBARS, and proline contents; measurement of the concentration of Na⁺ and K⁺ ions; and evaluation of gene expression by qPCR (TaHKT2;1, TaHKT1;5, TaSOS1, TaNa⁺/H⁺ vacuolar antiporter, TaV-PPase, TaV-ATPase, and TaP5CS)] and Raman spectroscopy. In this research, no significant difference was found in the increase of SOD, CAT, and POX antioxidant enzyme activities between the salt-treated and untreated experimental groups of the commercial cultivar, while there was a statistically significant increase in salt-treated advanced generation mutant lines as compared to control and the salt-treated commercial cultivar. Proline showed a statistically significant increase in all experimental groups compared to the untreated commercial cultivar. The degradation in the amount of chlorophyll was lower in the salt-treated advanced generation mutant lines than in the salt-treated commercial cultivar. According to gene expression studies, there were statistical differences at various levels in terms of Na⁺ and/or K⁺ uptake from soil to plant (TaHKT2;1, TaHKT1;5, and TaSOS1), and Na⁺ compartmentalizes into the cell vacuole (TaNa⁺/H⁺ vacuolar antiporter, Ta vacuolar pyrophosphatase, and Ta vacuolar H⁺-ATPase). The expression activity of TaP5CS, which is responsible for the transcription of proline, is similar to the content of proline in the current study. As a result of Raman spectroscopy, the differences in peaks represent the protein-related bands in mutant lines having a general decreasing trend in intensity when compared to the commercial cultivar. Amide-I (1,630 and 1,668 cm^-1), Histidine, Lysine, Arginine, and Leucine bands (823, 849, 1,241, 1,443, and 1,582 cm^-1) showed decreasing wavenumbers. Beta-carotene peaks at 1,153 and 1,519 cm^-1 showed increasing trends when the normalized Raman intensities of the mutant lines were compared.

Glutathione primed seed improved lead-stress tolerance in Brassica rapa L. through modulation of physio-biochemical attributes and nutrient uptake

Heavy metal toxicity is a major environmental issue that affects all life forms, including plants. The accumulation of lead (Pb) in agricultural soils is a significant contributor to reduced crop yields, and it poses serious health risks to people who consume lead-contaminated agricultural products. The current study was undertaken to investigate the beneficial effects of glutathione (GSH) on the amelioration of stress induced by Pb (300 mg kg-1 Pb) in Brassica rapa L. (turnip). For this purpose, B. rapa seeds primed with 25, 50, and 75 µmol L-1. The root and shoot length, seedling biomass, and leaf area, was reduced under Pb stress. Lead toxicity inhibited the net photosynthetic rate (31.36%), total chlorophyll content (74.54%) of B. rapa plants in comparison to control. Lead-stressed plants additionally exhibited changes in proline levels, as well as lower levels of total soluble protein and phenolic content. Nevertheless, seed priming with GSH resulted in higher concentrations of the nutritional content (Mg+2, Zn+2, Na+, K+) that increased Pb stress tolerance. The GSH2 treated seed enhanced the photosynthetic rate (46.34%), stomatal conductance (80.55%), and transpiration rate (53.125%) over Pb stress. Furthermore, GSH2 enhanced total soluble proteins (37.75%), phenolic content (58.38%), and DPPH (1.5fold) of turnip plant over control seedlings. According to our research, GSH2 primed B. rapa seed demonstrated a reduction in Pb toxicity, which could be used to help seedling establishment in soils contaminated with Pb.

Different vegetal protein hydrolysates distinctively alleviate salinity stress in vegetable crops: A case study on tomato and lettuce

Plants have evolved diverse plant-species specific tolerance mechanisms to cope with salt stress. However, these adaptive strategies often inefficiently mitigate the stress related to increasing salinity. In this respect, plant-based biostimulants have gained increasing popularity since they can alleviate deleterious effects of salinity. Hence, this study aimed to evaluate the sensitivity of tomato and lettuce plants grown under high salinity and the possible protective effects of four biostimulants based on vegetal protein hydrolysates. Plants were set in a 2 × 5 factorial experimental design completely randomized with two salt conditions, no salt (0 mM) and high salt (120 mM for tomato or 80 mM for lettuce), and five biostimulant treatments (C: Malvaceae-derived, P: Poaceae-derived, D: Legume-derived commercial 'Trainer^®', H: Legume-derived commercial 'Vegamin^®', and Control: distilled water). Our results showed that both salinity and biostimulant treatments affected the biomass accumulation in the two plant species, albeit to different extents. The salinity stress induced a higher activity of antioxidant enzymes (e.g., catalase, ascorbate peroxidase, guaiacol peroxidase and superoxide dismutase) and the overaccumulation of osmolyte proline in both lettuce and tomato plants. Interestingly, salt-stressed lettuce plants showed a higher accumulation of proline as compared to tomato plants. On the other hand, the treatment with biostimulants in salt-stressed plants caused a differential induction of enzymatic activity depending on the plant and the biostimulant considered. Overall, our results suggest that tomato plants were constitutively more tolerant to salinity than lettuce plants. As a consequence, the effectiveness of biostimulants in alleviating high salt concentrations was more evident in lettuce. Among the four biostimulants tested, P and D showed to be the most promising for the amelioration of salt stress in both the plant species, thereby suggesting their possible application in the agricultural practice.

Application of Amino Acids for High-Dosage Measurements with Electron Paramagnetic Resonance Spectroscopy

A comparative investigation of amino acids (proline, cysteine, and alanine) as dosimetric materials using electron paramagnetic resonance (EPR) spectroscopy in the absorbed dosage range of 1-25 kGy is presented. There were no signals in the EPR spectra of the samples before irradiation. After irradiation, the complex spectra were recorded. These results showed that the investigated amino acids were sensitive to radiation. In the EPR spectrum of cysteine after irradiation, RS• radicals dominated. The effects of the microwave power on the saturation of the EPR signals showed the presence of at least three different types of free radicals in proline. It was also found out that the DL-proline and cysteine had stable free radicals after irradiation and represented a linear dosage response up to 10 kGy. On the other hand, the amino acid alanine has been accepted by the International Atomic Energy Agency as a transfer standard dosimetry system. In view of this, the obtained results of the proline and cysteine studies have been compared with those of the alanine studies. The results showed that the amino acids proline and cysteine could be used as alternative dosimetric materials in lieu of alanine in a dosage range of 1-10 kGy of an absorbed dose of γ-rays using EPR spectroscopy. Regarding the radiation sensitivity, the following order of decreased dosage responses was determined: alanine > DL-proline > cysteine > L-proline.

Rajput V, Minkina T, Hayat S, Faisal M, Alatar AA, Abdel-Salam EM. CuO Nanoparticle-Mediated Seed Priming Improves Physio-Biochemical and Enzymatic Activities of Brassica juncea

The use of nanoparticles (NPs) in agricultural fields has risen to a level where people are considering NPs as an alternative to commercial fertilizers. The input of copper oxide NPs (CuO NPs) as seed primers was investigated in this study, and the growth indices of Brassica juncea such as phenotypic parameters, photosynthetic attributes, and biochemical parameters were measured during maximum vegetative growth stage, i.e., at 45 days after sowing. Surface sterilized seeds were soaked in varying concentrations (0, 2, 4, 8 and 16 mg/L) of CuO NPs for 15, 30, and/or 45 min. After those priming periods, the seeds were planted in pots and allowed to grow naturally. Among the different tested concentrations of CuO NPs, 4 mg/L of CuO NPs for 30 min seed priming proved to be best, and considerably increased the, shoot length (30%), root length (27%), net photosynthetic rate (30%), internal CO₂ concentration (28%), and proline content (41%). Besides, the performance of the antioxidant enzymes, viz, superoxide dismutase, catalase, peroxidase, and biochemical parameters such as nitrate reductase and carbonic anhydrase were also increased by several folds after the application of CuO NPs in B. juncea. The present study suggests that CuO NPs can be effectively used to increase the performance of B. juncea and may also be suitable for testing on other crop species.

Proline promotes proliferation and drug resistance of multiple myeloma by downregulation of proline dehydrogenase

Amino acids in the bone marrow microenvironment (BMME) are a critical factor for multiple myeloma (MM) progression. Here, we have determined that proline is elevated in BMME of MM patients and links to poor prognosis in MM. Moreover, exogenous proline regulates MM cell proliferation and drug resistance. Elevated proline in BMME is due to bone collagen degradation and abnormal expression of the key enzyme of proline catabolism, proline dehydrogenase (PRODH). PRODH is downregulated in MM patients, mainly as a result of promoter hypermethylation with high expression of DNMT3b. Thus, overexpression of PRODH suppresses cell proliferation and drug resistance of MM and exhibits therapeutic potential for treatment of MM. Altogether, we identify proline as a key metabolic regulator of MM, unveil PRODH governing MM progression and provide a promising therapeutic strategy for MM treatment.

Growth Stage-, Organ- and Time-Dependent Salt Tolerance of Halophyte Tripolium pannonicum (Jacq.) Dobrocz

Tripolium pannonicum (Jacq.) Dobrocz. is a member of the diverse group of halophytes with the potential for the desalination and reclamation of degraded land. The adaptive processes of T. pannonicum to salinity habitats are still not well recognized. Therefore, we evaluated the effect of NaCl (0, 200, 400, and 800 mM) on: (1) two plant growth stages, (2) the activity of antioxidant enzymes and concentration of H₂O₂ and the proline in roots, stems, and leaves, and (3) the effect of long- and short-term salt stress on physiological responses. Germination, pot experiments, and a biochemical analysis were performed. The effective T. pannonicum's seed germination was achieved in the control. We demonstrated that halophyte's organs do not simply tolerate high-salt conditions. The activities of APX, POD, and catalase observed at 400 mM and 800 mM NaCl were varied between organs and revealed the following pattern: root > leaves > stem. Proline was preferentially accumulated in leaves that were more salt-tolerant than other organs. Salt stress enhanced the activity of antioxidant enzymes and concentrations of salinity stress indicators in a time-dependent manner. Our study has indicated that salt tolerance is a complex mechanism that depends on the growth phase, organs, and duration of salinity exposure. The results have potential for further proteomic and metabolomic analyses of adaptive salt tolerance processes.

A New Regulatory Network Controls Chilling Injury in Peach Fruit by γ-Aminobutyric Acid

The control of chilling injury in peach fruit by a new regulator network, that exogenous γ-aminobutyric acid (GABA) regulates the metabolisms of polyamines (PAs), the GABA shunt, and proline, is still unclear. This study found that GABA induced an increase in the expression of PpADC and PpODC and a decrease in the expression of PpPAO expression, resulting in the accumulation of PAs. There was also an increase in the expression of PpGAD, which improved GABA content, and an increase in the expression of PpP5CS and PpOAT, which improved proline content. The correlation analysis showed that an increase in PpADC/PpP5CS expression was closely associated with the accumulation of putrescine and that the synergistic increase in the expression of PpODC and PpGAD/PpP5CS/PpOAT was closely related to the accumulation of spermine, proline, and GABA induced by GABA. Importantly, arginine and PpADC played a key role in putrescine accumulation, whereas ornithine and PpODC/PpOAT played a crucial role in the synergistic accumulation of spermine, proline, and GABA induced by GABA. This study provides new information on GABA-induced cold tolerance in peach fruit.

Examination of Different Sporidium Numbers of Ustilago maydis Infection on Two Hungarian Sweet Corn Hybrids' Characteristics at Vegetative and Generative Stages

Corn smut is one of the major diseases in corn production. The cob infection causes high economic and quality loss. This research investigated the effects of three different concentrations of corn smut infection (2500, 5000, and 10,000 sporidia/mL) on two Hungarian sweet corn hybrids (Desszert 73 and Noa). Plants were infected at the vegetative (V4-V5) and the generative (V7) stages. The effects of the corn smut infection were evaluated at 7 and 14 days after the pathogen infection (DAPI) at vegetative and at 21 DAPI at generative stages. The photosynthetic pigments (relative chlorophyll, chlorophyll-a and b, and carotenoids), malondialdehyde (MDA), and proline concentration, activities of the antioxidant enzymes [ascorbate peroxidase (APX), guaiacol peroxidase (POX), and superoxide dismutase (SOD)], morphological characteristics (plant height, stem and cob diameter, cob length, cob and kernel weights), mineral contents (Al, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, S, Sr, and Zn), and quality parameters (dry matter, fiber, fat, ash, nitrogen, and protein) were measured. At both sampling times (7 and 14 DAPI) in both hybrids, the corn smut infection reduced the photosynthetic pigments (relative chlorophyll, chlorophylls-a, and b, and carotenoids) irrespective of the spore concentration. Under the same conditions, the MDA and proline contents, as well as the activities of APX, POX, and SOD increased at both sampling times. The negative effects of the corn smut infection were also observed at the generative stage. Only the 10,000 sporidia/mL of corn smut caused symptoms (tumor growth) on the cobs of both hybrids at 21 DAPI. Similarly, this treatment impacted adversely the cob characteristics (reduced cob length, kernel weight, and 100 grains fresh and dry weight) for both hybrids. In addition, crude fat and protein content, Mg, and Mn concentration of grains also decreased in both hybrids while the concentration of Al and Ca increased. Based on these results, the sweet corn hybrids were more susceptible to corn smut at the vegetative stage than at the generative stage.

Diaporthe atlantica enhances tomato drought tolerance by improving photosynthesis, nutrient uptake and enzymatic antioxidant response

Functional symbiosis with fungal endophytes can help plants adapt to environmental stress. Diaporthe atlantica is one of the most abundant fungal taxa associated with roots of Festuca rubra subsp. pruinosa, a grass growing in sea cliffs. This study aimed to investigate the ability of a strain of this fungus to ameliorate the impact of drought stress on tomato plants. In a greenhouse experiment, tomato plants were inoculated with Diaporthe atlantica strain EB4 and exposed to two alternative water regimes: well-watered and drought stress. Several physiological and biochemical plant parameters were evaluated. Inoculation with Diaporthe promoted plant growth in both water treatments. A significant interactive effect of Diaporthe-inoculation and water-regime showed that symbiotic plants had higher photosynthetic capacity, water-use efficiency, nutrient uptake (N, P, K, Fe and Zn), and proline content under drought stress, but not under well-watered conditions. In addition, Diaporthe improved the enzymatic antioxidant response of plants under drought, through an induced mechanism, in which catalase activity was modulated and conferred protection against reactive oxygen species generation during stress. The results support that Diaporthe atlantica plays a positive role in the modulation of tomato plant responses to drought stress by combining various processes such as improving photosynthetic capacity, nutrient uptake, enzymatic antioxidant response and osmo-protectant accumulation. Thus, drought stress in tomato can be enhanced with symbiotic fungi.

Preparation, Characterization of New Antimicrobial Antitumor Hybrid Semi-Organic Single Crystals of Proline Amino Acid Doped by Silver Nanoparticles

Proline is water soluble amino acid extensively used in drug delivery systems. Compounds of cobalt (Co) transition metal have potent antimicrobial and anticancer activities. However, a drug delivery system combining proline cobalt is not reported yet. For the first time, new hybrid semi-organic single crystals of proline cobalt chloride (PCC) are prepared. The novelty of the article is also that single crystal proline cobalt chloride showed potent antimicrobial and antitumor activity. Doping of PCC by Ag⁰NPs significantly increased these biological activities. The anisotropic magnetic properties of single crystals can mitigate the cytotoxicity of Ag⁰NPs on normal cells. Silver nanoparticles (Ag⁰NPs) improved the crystal habits and physicochemical properties. Ag⁰NPs showed the best performance, paramagnetic materials n-type semiconductors due to delocalized excess electrons of Ag⁰NPs incorporated in the crystal lattice interstitially. Crystals have high absorptivity for UV-radiation electromagnetic radiation. Ag⁰NPs enhanced AC electrical conductivity up to 2.3 × 10⁴ Ω cm^-1 due to high electron density. Proline doped crystals are obtained in good purity as triclinic unit cell with having anisotropic magnetism. PCCAg⁰NPs crystal exhibited: high antimicrobial activities to various bacterial and fungal species, inhibition zone (mm): 21, 25, 24, 26, 30, 28, 12, and 46 for S. aureus, E. faecalis, S. typhi, E. coli, P. aerugino, K. pneumoniae, A. braselienses, and C. albicans, respectively, in comparison to ciprofloxacin antibiotic (23, 0, 26, 26, 25, 0, 0, 0) for the same tested species, respectively; higher cytotoxicity against breast cancer cells (IC₅₀ 22.1 μM) than the reference drug cisplatin (IC₅₀ 11.7 μM); and lower cytotoxicity to normal healthy lung cells MRC-5, (IC₅₀ 145.5 μM) than cisplatin (IC₅₀ 30.2 μM). Hence, this crystal is a candidate for chemotherapy of breast cancer.

Physiological and Biochemical Responses of Commercial Strawberry Cultivars under Optimal and Drought Stress Conditions

Improving the extent of adaptation and the choice of the most tolerant cultivar is the first step to mitigating the adverse effects of limited water, especially in susceptible plants such as strawberries. To address this issue, two commercial strawberry cultivars (Camarosa and Gaviota) were compared when irrigated to match 100, 75, 50, and 25% field capacity (FC) to simulate the control, slight, moderate, and severe drought stress conditions, respectively. Drought stress induced the reduction of total chlorophyll, carotenoid, relative water content, and phenolic content significantly, whereas the activity of antioxidant enzymes, electrolyte leakage, osmolyte accumulation, and oxidative markers upsurged progressively in drought severity-dependent behavior. Gaviota produced more proline, hydrogen peroxide as a marker of membrane lipid peroxidation and disposed of by higher electrolyte leakage, significantly. On the other hand, Camarosa having higher soluble carbohydrates as well as enzymatic and non-enzymatic antioxidants could be considered a drought-tolerant cultivar. Genotypic variation between these cultivars could be used in breeding projects to promote drought-tolerant strawberries in the future.

Dietary Supplements with Proline-A Comprehensive Assessment of Their Quality

Dietary supplements are food products commonly used worldwide to obtain nutritional and physiological effects. They can contain a wide variety of active substances and can be administered for health and disease. Their use can be beneficial if justified, and their quality is adequate. Unfortunately, data on the quality of supplements is scarce. As part of this work, we assess the quality of seven dietary supplements containing proline. The preparations were produced in the EU and the USA. The quality assessment consisted of the detection of potential impurities, the determination of the content of the main ingredient, and the release of proline. The technique used to analyse impurities and proline (Pro) content was liquid chromatography coupled with tandem mass spectrometry. We detected five contaminants. The main ingredient content was in the range of 73-121% in capsules and 103-156% in tablets. Five of the seven analysed dietary supplements released below 80% Pro (for each tablet/capsule at pH 1.2). One of the supplements may be inactive because a very low release of Pro was reported. The results, we hope, will increase consumer awareness of the quality of these preparations and result in a change in the regulations governing the marketing of these preparations, at least by making release testing mandatory.