Cysteine Content Research Articles

Melatonin Reverses High-Temperature-Stress-Inhibited Photosynthesis in the Presence of Excess Sulfur by Modulating Ethylene Sensitivity in Mustard.

Melatonin is a pleiotropic, nontoxic, regulatory biomolecule with various functions in abiotic stress tolerance. It reverses the adverse effect of heat stress on photosynthesis in plants and helps with sulfur (S) assimilation. Our research objective aimed to find the influence of melatonin, along with excess sulfur (2 mM SO42-), in reversing heat stress's impacts on the photosynthetic ability of the mustard (Brassica juncea L.) cultivar SS2, a cultivar with low ATP-sulfurylase activity and a low sulfate transport index (STI). Further, we aimed to substantiate that the effect was a result of ethylene modulation. Melatonin in the presence of excess-S (S) increased S-assimilation and the STI by increasing the ATP-sulfurylase (ATP-S) and serine acetyltransferase (SAT) activity of SS2, and it enhanced the content of cysteine (Cys) and methionine (Met). Under heat stress, melatonin increased S-assimilation and diverted Cys towards the synthesis of more reduced glutathione (GSH), utilizing excess-S at the expense of less methionine and ethylene and resulting in plants' reduced sensitivity to stress ethylene. The treatment with melatonin plus excess-S increased antioxidant enzyme activity, photosynthetic-S use efficiency (p-SUE), Rubisco activity, photosynthesis, and growth under heat stress. Further, plants receiving melatonin and excess-S in the presence of norbornadiene (NBD; an ethylene action inhibitor) under heat stress showed an inhibited STI and lower photosynthesis and growth. This suggested that ethylene was involved in the melatonin-mediated heat stress reversal effects on photosynthesis in plants. The interaction mechanism between melatonin and ethylene is still elusive. This study provides avenues to explore the melatonin-ethylene-S interaction for heat stress tolerance in plants.

Flavor-protein interactions for four plant protein isolates and whey protein isolate with aldehydes

Aldehydes are important flavor molecules to consider in plant-based products. Here, the flavor retention of a series of saturated aldehydes and mono-unsaturated aldehydes (2-alkenals) with different chain lengths (C4, C6, C8, and C10) in dispersions with protein isolates of pea, soy, fava bean, chickpea, and whey (as reference) was analyzed with APCI-TOF-MS. The headspace concentrations of alkenals were lower than aldehydes, meaning alkenals were retained more than saturated aldehydes. The retention was modeled by assuming hydrophobic interactions and covalent interactions. The ratio between the hydrophobic interaction parameter and the covalent parameter showed that covalent interactions are mainly important for butanal and butenal (C4). For the other aldehydes, hydrophobic interactions became increasingly important. Correlations were found between the chemical interaction parameters and the cysteine and methionine content of the different proteins. The obtained model parameters for each set of proteins and flavors allow the prediction of flavor retention when developing a flavored product with high protein content.

Role of Antimicrobial Peptides in Immunity of Parasitic Leeches

The review summarizes the current state of knowledge about leech immunity, with emphasis on the special role of antimicrobial peptides (AMPs), and highlights the wide variety of primary AMP structures, which seem to correlate with a variety of life strategies and the ecology of ectoparasites. Antimicrobial proteins and AMPs are a diverse class of natural molecules that are produced in all living organisms in response to an attack by a pathogen and are essential components of the immune system. AMPs can have a wide range of antibiotic activities against foreign and opportunistic bacteria, fungi, and viruses. AMPs play an important role in selection of colonizing bacterial symbionts, thus helping multicellular organisms to cope with certain environmental problems. AMPs are especially important for invertebrates, which lack an adaptive immune system. Although many AMPs are similar in physicochemical properties (a total length from 10 to 100 amino acids, a positive total charge, or a high cysteine content), their immunomodulatory activities are specific for each AMP type.

Calcium-assisted sortase A cleavage of SUMOylated metallothionein constructs leads to high-yield production of human MT3

BackgroundMammalian metallothioneins (MTs) are small (6–7 kDa), intracellular, cysteine-rich, metal-binding proteins involved, inter alia, in the homeostasis of zinc and copper, detoxification of heavy metals, antioxidation against reactive oxygen species, and protection against DNA damage. The high cysteine content (~ 30%) in MTs makes them toxic to bacterial cells during protein production, resulting in low yield. To address this issue, we present for the first time a combinatorial approach using the small ubiquitin-like modifier (SUMO) and/or sortase as fusion tags for high-level expression of human MT3 in E. coli and its purification by three different strategies.ResultsThree different plasmids were generated using SUMO, sortase A pentamutant (eSrtA), and sortase recognition motif (LPETG) as removable fusion tags for high-level expression and purification of human MT3 from the bacterial system. In the first strategy, SUMOylated MT3 was expressed and purified using Ulp1-mediated cleavage. In the second strategy, SUMOylated MT3 with a sortase recognition motif at the N-terminus of MT3 was expressed and purified using sortase-mediated cleavage. In the final strategy, the fusion protein His6-SUMO-eSrtA-LPETG-MT3 was expressed and purified by one-step sortase-mediated inducible on-bead autocleavage. Using these three strategies the apo-MT3 was purified in a yield of 11.5, 11, and 10.8 mg/L, respectively, which is the highest yield achieved for MT expression and purification to date. No effect of MT3 on Ni2+-containing resin was observed.ConclusionThe SUMO/sortase-based strategy used as the production system for MT3 resulted in a very high expression level and protein production yield. The apo-MT3 purified by this strategy contained an additional glycine residue and had similar metal binding properties as WT-MT3. This SUMO-sortase fusion system is a simple, robust, and inexpensive one-step purification approach for various MTs as well as other toxic proteins with very high yield via immobilized metal affinity chromatography (IMAC).

In Situ Synthesis of Keratin and Melanin Chromophoric Submicron Particles.

In humans, melanin plays an esthetic role, dictating hair and skin color and traits, while keratin is the protein that comprises most of the epidermis layer. Eumelanin and pheomelanin are types of melanin synthesized from the same building blocks via enzymatic oxidation. Pheomelanin has an additional building block, cysteine amino acid, which affects its final structure. Keratin contains high cysteine content, and by exploiting free thiols in hydrolyzed keratin, we demonstrate the formation of keratin-melanin (KerMel) chromophoric submicron particles. Cryo-TEM analyses found KerMel particle sizes to be 100-300 nm and arranged in the form of a central keratin particle with polymerized l-dopa chains. Attenuated total reflection (ATR)-FTIR, UV-vis, and fluorescence measurements identified new chemical bonds, indicating the formation of KerMel particles. Finally, KerMel replicated natural skin tones and proved cytocompatibility for human epidermal keratinocytes at concentrations below 0.1 mg/mL. Taken together, KerMel is a novel, tunable material that has the potential to integrate into the cosmetic industry.

Mercury and amino acid content relations in northern pike (Esox lucius) in subarctic lakes along a climate-productivity gradient

Mercury is a highly toxic element for consumers, but its relation to amino acids and physiology of wild fish is not well known. The main aim of this study was to evaluate how total mercury content (THg) of northern pike (Esox lucius) is related to amino acids and potentially important environmental and biological factors along a climate-productivity gradient of ten subarctic lakes. Linear regression between THg and sixteen amino acids content [nmol mg−1 dry weight] from white dorsal muscle of pike from these lakes were tested. Lastly, a general linear model (GLM) for age-corrected THg was used to test which factors are significantly related to mercury content of pike. There was a positive relationship between THg and proline. Seven out of sixteen analysed amino acids (histidine, threonine, arginine, serine, glutamic acid, glycine, and aspartic acid) were significantly negatively related to warmer and more productive lakes, while THg showed a positive relationship. GLM model indicated higher THg was found in higher trophic level pike with lower cysteine content and inhabiting warmer and more productive lakes with larger catchment containing substantial proportion of peatland area. In general, THg was not only related to the biological and environmental variables but also to amino acid content.

Metabolic Profiling of a Fast Neutron Soybean Mutant Reveals an Increased Abundance of Isoflavones.

A total of 718 metabolites were identified in leaves and seeds of the soybean (Glycine max (L.) Merr., Fabaceae) fast neutron (FN) mutant 2012CM7F040p05ar154bMN15, which was previously shown to have 21 genes deleted and higher protein content in seeds as compared to wild-type. Among the identified metabolites, 164 were found only in seeds, 89 only in leaves, and 465 in both leaves and seeds. Metabolites that exhibited higher abundance in the mutant leaf than in the wild type include the flavonoids afromosin, biochanin A, dihydrodaidzein, and apigenin. Mutant leaves also exhibited a higher accumulation of glycitein-glucoside, dihydrokaempferol, and pipecolate. The seed-only metabolites that were found in higher abundance in the mutant compared to the wild type included 3-hydroxybenzoate, 3-aminoisobutyrate, coenzyme A, N-acetyl-β-alanine, and 1-methylhistidine. Among several amino acids, the cysteine content increased in the mutant leaf and seed when compared to the wild type. We anticipate that the deletion of acetyl-CoA synthase created a negative feedback effect on carbon dynamics, resulting in increased amounts of cysteine and isoflavone-associated metabolites. Metabolic profiling provided new insight into the cascading effect of gene deletions that helps breeders to produce value-added nutritional seed traits.

Study on Phyllosphere Microbial Community of Nettle Leaf during Different Seasons

Nettle (Urtica cannabina) is an excellent feed resource widely distributed worldwide. Phyllosphere microbes are important as they have living conditions similar to those of the above-ground parts of host plants. Exploring amino acids (AA) and microorganisms can further understand the growth of plants in different seasons. The present study investigated the content of AA and phyllosphere microbes’ structure of nettle plants in different seasons. The results found that AA contents varied significantly with the season, such as alanine, aspartate, cysteine, glutamate, glycine, and methionine contents decreased significantly from spring to winter (p < 0.05), the contents of arginine, histidine, serine, and lysine were highest in summer (p < 0.05). The results suggested that the diversity of bacteria and fungi both increased during winter. During winter, Sphingomonas (relative abundance 25.22–28.45%) and Filobasidum (27.6–41.14%) became dominant. According to the redundancy analysis (RDA) of the correlation between AA and microbes, these two microbes were both the most important factors and showed a negative correlation with AA during winter. Thus, seasons could significantly affect the distribution of phyllosphere microbial communities on the nettle, especially in winter. According to the function prediction(PICRUS2 (KEGG pathway) and FUNGuild) results, the bacteria in the phyllosphere of U. cannabina mainly participated in metabolism. Pathogenic fungi were relatively high in autumn. The present study reveals the influence of seasonal change on the phyllosphere microbial community in U. cannabina.

Oridonin inhibits Hela cell proliferation via downregulation of glutathione metabolism: a new insight from metabolomics.

This study aims to elucidate Oridonin' s inhibitory mechanism to cervical cancer using metabolomics methods and pharmacological assays. Network pharmacology and KEGG pathway analysis are used to identify overlapped targets and involved metabolic pathways. UPLC-MS/MS metabolomics analysis is used to determine altered metabolites after Oridonin treatment. Other bioassays are also employed to uncover the changes in critical molecules that are highly related to altered metabolites. Seventy-five overlapped targets are identified between Oridonin and cervical cancer. Twenty-one metabolites involved in tricarboxylic acid cycle glutathione metabolism, branched-chain amino acid metabolism and so on changes significantly after Oridonin treatment. Oridonin treatment significantly reduces the content of cysteine and inhibit the catalytic activity of glutamine-cysteine ligase subunit, a rate-limiting enzyme for the synthesis of glutathione. As a result, the content of glutathione is also reduced. The antioxidant enzyme glutathione peroxidase 4 which uses glutathione as a cofactor, is inactivated, resulting in a burst release of reactive oxygen species. The ATP content is also significantly reduced in Hela cells after Oridonin treatment. This study finds that Oridonin treatment induces Hela cell apoptosis possibly via inhibition of the glutathione metabolism.

Roles of Different β-Defensins in the Human Reproductive System: A Review Study.

Human β-defensins (hBDs) are cationic peptides with an amphipathic spatial shape and a high cysteine content. The members of this peptide family have been found in the human body with various functions, including the human reproductive system. Of among β-defensins in the human body, β-defensin 1, β-defensin 2, and β-defensin 126 are known in the human reproductive system. Human β-defensin 1 interacts with chemokine receptor 6 (CCR6) in the male reproductive system to prevent bacterial infections. This peptide has a positive function in antitumor immunity by recruiting dendritic cells and memory T cells in prostate cancer. It is necessary for fertilization via facilitating capacitation and acrosome reaction in the female reproductive system. Human β-defensin 2 is another peptide with antibacterial action which can minimize infection in different parts of the female reproductive system such as the vagina by interacting with CCR6. Human β-defensin 2 could play a role in preventing cervical cancer via interactions with dendritic cells. Human β-defensin 126 is required for sperm motility and protecting the sperm against immune system factors. This study attempted to review the updated knowledge about the roles of β-defensin 1, β-defensin 2, and β-defensin 126 in both the male and female reproductive systems.

BIOINFORMATICS EVALUATION OF CRISP2 GENE SNPs AND THEIR IMPACTS ON PROTEIN

This study evaluated the CRISP2 gene's functional single nucleotide polymorphisms, and its results may be advantageous for future population-based studies and early diagnostic discoveries, particularly in developing effective treatments. The CRISP2 gene encodes a secretory protein with a high cysteine content, which belongs to the family of cysteine-rich secretory proteins (CRISP). SNPs are genetic variations that may affect a protein's structure or functionality. Prior to carrying out a broader population investigation, it is possible to evaluate suspected functional SNPs since it is challenging to uncover functional SNPs in disease-linked genes. As a result, using various bioinformatic prediction models, the potentially harmful three SNPs of the CRISP2 gene were predicted in this in-silico study from the neutral ones. Out of a pool of 260 nsSNPs, three SNPs (L56V, M176I, and C196R) been selected to anticipate their impacts on functions and structures along with their capability to impair protein stability. Actually, two of the three SNPs in the CRISP2 gene L56V and C196R were identified as possibly detrimental, although M176I was not. But all of these SNPs dropped significantly protein stability, per the I-Mutant suite.

Selection of Faba Bean (Vicia faba L.) Genotypes for High Yield, Essential Amino Acids and Low Anti-Nutritional Factors

One of the important edible legumes, the faba bean (Vicia faba L.) contains high protein levels and amino acids in its seeds essential for human nutrition and animal feeding; it also consists of anti-nutritional factors such as vicine, convicine, and tannin. For a balanced and healthy diet, faba bean cultivars should be improved for high seed yield, essential amino acids, and low anti-nutritional factors. The aims of this study were to select faba bean genotypes for (i) high yield, (ii) low anti-nutritional factors, and (iii) essential amino acids. A total of 12 faba bean genotypes, including 10 genotypes with low tannin content and 2 local checks, were assessed for phenological, morphological, and agronomical traits, as well as some biochemical characteristics including essential amino acids and low anti-nutritional factors. A local population, Atlidere, and a breeding line with low tannin content, FLIP08-016FB, had the highest yield. FLIP08-016FB had not only the highest lysine, methionine, and cysteine content, but also the highest yield and low anti-nutritional factors. FLIP08-016FB was selected for a balanced and healthy diet as it had a high seed yield, essential amino acids, and low anti-nutritional factors.

Amino acid content in spring common wheat grain

The aim of the study was to determine the differences in the content of amino acids in wheat grains of the world collection of VIR in the agro-climatic conditions of the Republic of Tatarstan and to search for sources of increased content of essential amino acids for the use of these data in breeding. The study was conducted in 2021-2022 at the experimental base of the Tatar Research Institute of Agriculture of the Kazan Scientific Center of the Russian Academy of Sciences, located 15 km away from Kazan, the soil of the experimental site is gray forest. 354 samples of spring wheat were studied. The determination of the content of seventeen amino acids and protein in wheat grain was carried out using the near-infrared spectroscopy method on the DS 2500F device from FOSS. The protein content in the grain has a significant effect on the amount of essential acids. The correlation between the protein content and the amount of essential acids in wheat grain is high in 2021. r = 0.91 ± 0.02 and average in 2022. r = 0.69± 0.04. The highest content of glutamine in wheat grain was noted - up to 2.22 % and proline - up to 1.55 %. The source of high grain content of histidine 0.38- 0.40 %, isoleucine 0.53-0.54 %, lysine 0.61-0.62 %, methionine 0.28-0.30 %, phenylalanine 0.66-0.67 %, threonine 0.52-0.56 % and tyrosine 0.31-0.36 % was the Ranee sample (k-26982). The Panifor sample was a source of high grain content of cysteine 0.58-0.63 %, histidine 0.39 % and threonine 0.51-0.58 %. The Arrino sample (k-65995) is a source of high grain content of leucine 0.82-0.91 %, tyrosine 0.31-0.34 % and valine 0.75-0.78 %. According to the lysine content in protein (grams of amino acid per 100 grams of protein), samples Ranee (k-26982) - 3.63-3.66 and NIL Avocet Yr15 (k-66241) - 2.86-4.52 were isolated. According to the content of methionine in the protein, samples of Uffo (k- 66798) - 1.80-1.8 and Fiorina (k-66034) - 1.70-1.91 were isolated. According to the threonine content, three samples Ranee (k-26982) - 3.04-3.36, Panifor (k-66039) - 3.09-3.20 and Cub (k- 62510) - 3.07-3.20 were distinguished. The source of the high tryptophan content in the protein were samples Ethos (k- 65002) - 2.00-2.27, Tulaykovskaya 108 (k- 65452) - 2.01-2.26 and Ekada 109 (k-66239) - 2.07-2.14.

Protein, Amino Acids and Yield of Lentil (Lens culneris L.) Expressed Differential Response to Incremental Doses of Sulphur and Boron in Rice Fallow Soil of Mirzapur

Background: Lentil is an important legume crop and plays an important role in human nutrition and soil fertility improvement. It contains 57-60% carbohydrate, 24-26% protein, 3.2% fiberand only 1.3% fat with the full complement of amino acids. It is a potential crop for about 10 million hectares of rice-fallow areas of eastern India. This study aimed to standardized Sulphur and Boron requirements of Lentil in Eastern India. Methods: The experiment was conducted in a glass house during 2018-19 and 2019-20 in a factorial completely randomized design with three replications and 16 treatment combinations of sulphur and boron. The treatment combinations were product of 4 levels each of sulphur and boron as 0, 15, 30 and 45 kg ha-1 (0, 0.067, 0.134 and 0.201 g pot-1) and 0, 1, 2 and 3 kg ha-1 (0, 0.004, 0.009 and 0.013 g pot-1), respectively. Lentil grain yield was observed at harvest and sulphur-containing amino acids, as well as seed nutrient content, were analyzed followingstandard operating procedures. Result: Lentil grain yield was enhanced by 1.85 times with a combined application of 45 kg S and 2 kg B ha-1 with a recommended dose of NPK. The sulphur-containing amino acids namely methionine, cystine and cysteine content showed significant improvement with increasing levels of sulphur application however were not significantly affected with boron levels. The protein content in lentil seed increased considerably with application of sulphur levels as compared to boron levels and it was highest with 30kg S ha-1 + 2kg B ha-1 along with recommended dose of NPK fertilizers.

The diversification of the antimicrobial peptides from marine worms is driven by environmental conditions

Antimicrobial peptides (AMPs) play a key role in the external immunity of animals, offering an interesting model for studying the influence of the environment on the diversification and evolution of immune effectors. Alvinellacin (ALV), arenicin (ARE) and polaricin (POL, a novel AMP identified here), characterized from three marine worms inhabiting contrasted habitats (‘hot’ vents, temperate and polar respectively), possess a well conserved BRICHOS domain in their precursor molecule despite a profound amino acid and structural diversification of the C-terminal part containing the core peptide. Data not only showed that ARE, ALV and POL display an optimal bactericidal activity against the bacteria typical of the habitat where each worm species lives but also that this killing efficacy is optimal under the thermochemical conditions encountered by their producers in their environment. Moreover, the correlation between species habitat and the cysteine contents of POL, ARE and ALV led us to investigate the importance of disulfide bridges in their biological efficacy as a function of abiotic pressures (pH and temperature). The construction of variants using non-proteinogenic residues instead of cysteines (α-aminobutyric acid variants) leading to AMPs devoid of disulfide bridges, provided evidence that the disulfide pattern of the three AMPs allows for a better bactericidal activity and suggests an adaptive way to sustain the fluctuations of the worm's environment. This work shows that the external immune effectors exemplified here by BRICHOS AMPs are evolving under strong diversifying environmental pressures to be structurally shaped and more efficient/specific under the ecological niche of their producer.

Ferrous sulfate reverses cerebral metabolic abnormality induced by minimal hepatic encephalopathy.

Orally administered ferrous iron was previously reported to significantly improve the cognition and locomotion of patients with minimal hepatic encephalopathy (MHE). However, the metabolic mechanisms of the therapeutic effect of ferrous iron are unknown. In this study, MHE was induced in rats by partial portal vein ligation (PPVL), and was treated with ferrous sulfate. The Morris water maze was used to evaluate the cognitive condition of the rats. The metabolites observed by NMR and validated by liquid chromatography-mass spectrometry were defined as the key affected metabolites. The enzyme activities and trace element contents in the rat brains were also investigated. The Mn content was found to be increased but the ferrous iron content decreased in the cortex and striatum in MHE. Decreased oxoglutarate dehydrogenase activity and increased glutamine synthetase (GS) and pyruvate carboxylase (PC) activity were observed in the cortex of MHE rats. Decreased pyruvate dehydrogenase activity and increased GS and PC activity were observed in the striatum of MHE rats. The levels of BCAAs and taurine were significantly decreased, and the contents of GABA, lactate, arginine, aspartate, carnosine, citrulline, cysteine, glutamate, glutamine, glycine, methionine, ornithine, proline, threonine and tyrosine were significantly increased. These metabolic abnormalities described above were restored after treatment with ferrous sulfate. Pathway enrichment analysis suggested that urea cycle, aspartate metabolism, arginine and proline metabolism, glycine and serine metabolism, and glutamate metabolism were the major metabolic abnormalities in MHE rats, but these processes could be restored and cognitive impairment could be improved by ferrous sulfate administration.

THE AMINO ACIDS CONTENT IN GRAPE BY-PRODUCTS FROM SLOVAKIA AND AUSTRIA

The aim of the experiment was to determine the amino acid content in 3 grape varieties by-products (bunch, pomace, stem) from Austria (AT) and Slovakia (SK). In total, 54 samples from 3 varieties Zweigelt (ZG), Pinot Blanc (PB) and Green Veltliner (GV) white skinned from 6 different locations (Nitra and Vienna wine region) of Vitis vinifera sp. were analysed. In each variety the amino acids composition was determined for the whole grape (bunch) and by-products of wine industry (pomace, stems). Samples of grape by-products were freeze dried, homogenized and analysed for amino acids concentration using amino acid analyzer AAA 400 (Ingos, Prague). Descriptive statistics (means, standard error of mean, minimum maximum), differences between varieties (Tukey test, p < 0.05) using One-way ANOVA and differences between the countries with independent samples T-test (p < 0.05) by IBM SPSS v. 20.0 were generated. After the amino acid analysis in grape bunch, pomace and stem in general the highest content of glutamic and aspartic acid was found. However, the grape pomace amino acid content is highly variable and statistically different between the varieties and countries. In contrary, lower variability in amino acids content between the varieties was found in grape stem. However, similar pattern in amino acids with the lowest content between the countries and varieties in grape by-products was observed. Finally, low content of Cysteine, Methionine, Histidine and Proline was found.

Effect of Thermal Processes on S-Allyl Cysteine Content in Black Garlic.

As a key component of black garlic (BG) products, S-allyl cysteine (SAC) is useful in reducing oxidative stress and inflammation. Several BG products with a high SAC content have been developed by thermal processing; however, the optimum conditions for thermal treatment for producing Thai garlic (multicloves) with a high SAC content compared to Chinese garlic (single clove) are still unknown. Moreover, the mechanism underlying the increase in SAC content in BG is unclear. Thus, this study aimed to investigate the optimum thermal condition for developing Thai BG with high SAC content base on methods A (70 °C and 80% RH) and B (60-75 °C and 80-85% RH). The total phenolic contents and antioxidant activities of Thai fresh garlic, Thai BG, and their powder forms were also compared. Method A worked the best for both types of garlic. The results indicated that the SAC content increased significantly after 7 days of fermentation and decreased drastically afterward with prolonged heat treatment. The optimum thermal condition for producing Thai fresh garlic and Chinese fresh garlic with high SAC content was 70 °C and a relative humidity of 80% for 12 days in an industrial fermentation chamber. The SAC content of Thai BG and Chinese BG increased approximately 139- and 122-fold, respectively. Furthermore, significant antioxidant capabilities determined by ferric ion-reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and oxygen radical absorbance capacity assays were 34-, 6-, and 3-fold higher, respectively, than those of fresh garlic.

Structural Role of Cadmium and Zinc in Metallothionein Oxidation by Hydrogen Peroxide: The Resilience of Metal-Thiolate Clusters.

Oxidative stress is a state involving an imbalance of reactive oxygen species in a cell and is linked to a variety of diseases. The metal-binding protein metallothionein (MT) may play a role in protection due to its high cysteine content. Many studies have shown that oxidative stress will cause MT to both form disulfide bonds and release bound metals. However, studies on the more biologically relevant partially metalated MTs have been largely neglected. Additionally, most studies to date have used spectroscopic methods that cannot detect specific intermediate species. In this paper, we describe the oxidation and the subsequent metal displacement pathway of fully and partially metalated MTs with hydrogen peroxide. The rates of the reactions were monitored using electrospray ionization mass spectrometry (ESI-MS) techniques, which resolved and characterized the individual intermediate Mx(SH)yMT species. The rate constants were calculated for each species formation. Through ESI-MS and circular dichroism spectroscopy, it was found that the three metals in the β-domain were the first to be released from the fully metalated MTs. The Cd(II) in the partially metalated Cd(II)-bound MTs rearranged to form a protective Cd4MT cluster structure upon exposure to oxidation. The partially metalated Zn(II)-bound MTs oxidized at a faster rate as the Zn(II) did not rearrange in response to oxidation. Additionally, density functional theory calculations showed that the terminally bound cysteines were more negative and thus more susceptible to oxidation than the bridging cysteines. The results of this study highlight the importance of metal-thiolate structures and metal identity in MT's response to oxidation.

Glomus mosseae improved the adaptability of alfalfa (Medicago sativa L.) to the coexistence of cadmium-polluted soils and elevated air temperature.

The coexistence of heavy metal-polluted soils and global warming poses serious threats to plants. Many studies indicate that arbuscular mycorrhizal fungi (AMF) can enhance the resistance of plants to adverse environments such as heavy metals and high temperature. However, few studies are carried out to explore the regulation of AMF on the adaptability of plants to the coexistence of heavy metals and elevated temperature (ET). Here, we investigated the regulation of Glomus mosseae on the adaptability of alfalfa (Medicago sativa L.) to the coexistence of cadmium (Cd)-polluted soils and ET. G. mosseae significantly enhanced total chlorophyll and carbon (C) content in the shoots by 15.6% and 3.0%, respectively, and Cd, nitrogen (N), and phosphorus (P) uptake by the roots by 63.3%, 28.9%, and 85.2%, respectively, under Cd + ET. G. mosseae significantly increased ascorbate peroxidase activity, peroxidase (POD) gene expression, and soluble proteins content in the shoots by 13.4%, 130.3%, and 33.8%, respectively, and significantly decreased ascorbic acid (AsA), phytochelatins (PCs), and malondialdehyde (MDA) contents by 7.4%, 23.2%, and 6.5%, respectively, under ET + Cd. Additionally, G. mosseae colonization led to significant increases in POD (13.0%) and catalase (46.5%) activities, Cu/Zn-superoxide dismutase gene expression (33.5%), and MDA (6.6%), glutathione (22.2%), AsA (10.3%), cysteine (101.0%), PCs (13.8%), soluble sugars (17.5%), and proteins (43.4%) contents in the roots and carotenoids (23.2%) under ET + Cd. Cadmium, C, N, G. mosseae colonization rate, and chlorophyll significantly influenced shoots defenses and Cd, C, N, P, G. mosseae colonization rate, and sulfur significantly affected root defenses. In conclusion, G. mosseae obviously improved the defense capacity of alfalfa under ET + Cd. The results could improve our understanding of the regulation of AMF on the adaptability of plants to the coexistence of heavy metals and global warming and phytoremediation of heavy metal-polluted sites under global warming scenarios.