Mass spectrometry-based quantification and spatial localization of small organic acid exudates in plant roots under phosphorus deficiency and aluminum toxicity.

Low-molecular-weight organic acid (OA) extrusion by plant roots is critical for plant nutrition, tolerance to cations toxicity, and plant-microbe interactions. Therefore, methodologies for the rapid and precise quantification of OAs are necessary to be incorporated in the analysis of roots and their exudates. The spatial location of root exudates is also important to understand the molecular mechanisms directing OA production and release into the rhizosphere. Here, we report the development of two complementary methodologies for OA determination, which were employed to evaluate the effect of inorganic ortho-phosphate (Pi) deficiency and aluminum toxicity on OA excretion by Arabidopsis roots. OA exudation by roots is considered a core response to different types of abiotic stress and for the interaction of roots with soil microbes, and for decades has been a target trait to produce plant varieties with increased capacities of Pi uptake and Al tolerance. Using targeted ultra-performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UPLC-HRMS/MS), we achieved the quantification of six OAs in root exudates at sub-micromolar detection limits with an analysis time of less than 5 min per sample. We also employed targeted (MS/MS) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to detect the spatial location of citric and malic acid with high specificity in roots and exudates. Using these methods, we studied OA exudation in response to Al toxicity and Pi deficiency in Arabidopsis seedlings overexpressing genes involved in OA excretion. Finally, we show the transferability of the MALDI-MSI method by analyzing OA excretion in Marchantia polymorpha gemmalings subjected to Pi deficiency.

Activity of Adesmia boronioides resinous exudate against phytopathogenic bacteria.

Resinous exudate obtained from the aerial parts of Adesmia boronioides Hook.f. were evaluated to determine anti-phytopathogenic effects. Briefly, resinous exudate was obtained by dipping fresh plant material in dichloromethane; chemical composition was determined by GC-MS; and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated against four phytopathogenic bacteria. Resinous exudate yield was 8.5% (resin/fresh plant), of which esquel-6-en-9-one (14.25%), esquel-7-en-9-one (5.86%), and veratric acid (2.59%) were the effective antibacterial compounds. Tested against Pectobacterium carotovorum subsp. carotovora, Erwinia amylovora, Bacillus subtilis, and Pseudomonas syringae, MICs and MBCs ranged from 16 to 128 µg/mL and 32-256 µg/mL, respectively. These results provide initial evidence that resinous bush A. boronioides is a new and alternative source of substances with agricultural interest.

Effects of root morphology, respiration and carboxylate exudation on carbon economy in two non-mycorrhizal lupines under phosphorus deficiency.

Under phosphorus (P) deficiency, Lupinus albus develops cluster roots that allow efficient P acquisition, while L. angustifolius without cluster roots also grows well. Both species are non-mycorrhizal. We quantitatively examined the carbon budgets to investigate the different strategies of these species. Biomass allocation, respiratory rates, protein amounts and carboxylate exudation rates were examined in hydroponically-grown plants treated with low (1 µM; P1) or high (100 µM; P100) P. At P1, L. albus formed cluster roots, and L. angustifolius increased biomass allocation to the roots. The respiratory rates of the roots were faster in L. albus than in L. angustifolius. The protein amounts of the non-phosphorylating alternative oxidase and uncoupling protein were greater in the cluster roots of L. albus at P1 than in the roots at P100, but similar between the P treatments in L. angustifolius roots. At P1, L. albus exuded carboxylates at a faster rate than L. angustifolius. The carbon budgets at P1 were surprisingly similar between the two species, which is attributed to the contrasting root growth and development strategies. L. albus developed cluster roots with rapid respiratory and carboxylate exudation rates, while L. angustifolius developed a larger root system with slow respiratory and exudation rates.

Influence of Herbal Medicines on HMGB1 Release, SARS-CoV-2 Viral Attachment, Acute Respiratory Failure, and Sepsis. A Literature Review.

By attaching to the angiotensin converting enzyme 2 (ACE2) protein on lung and intestinal cells, Sudden Acute Respiratory Syndrome (SARS-CoV-2) can cause respiratory and homeostatic difficulties leading to sepsis. The progression from acute respiratory failure to sepsis has been correlated with the release of high-mobility group box 1 protein (HMGB1). Lack of effective conventional treatment of this septic state has spiked an interest in alternative medicine. This review of herbal extracts has identified multiple candidates which can target the release of HMGB1 and potentially reduce mortality by preventing progression from respiratory distress to sepsis. Some of the identified mixtures have also been shown to interfere with viral attachment. Due to the wide variability in chemical superstructure of the components of assorted herbal extracts, common motifs have been identified. Looking at the most active compounds in each extract it becomes evident that as a group, phenolic compounds have a broad enzyme inhibiting function. They have been shown to act against the priming of SARS-CoV-2 attachment proteins by host and viral enzymes, and the release of HMGB1 by host immune cells. An argument for the value in a nonspecific inhibitory action has been drawn. Hopefully these findings can drive future drug development and clinical procedures.

Oral treatment with Aloe polysaccharide ameliorates ovalbumin-induced atopic dermatitis by restoring tight junctions in skin.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. A hallmark of AD is dry itchy skin that results from defects in the epidermal barrier function. Aloe vera is used widely to promote general health and is administered topically to treat skin conditions such as eczema, burns and wounds. However, effects of A vera on AD were not fully elucidated. In this study, we investigated the oral administration of processed A vera gel (PAG) containing low molecular weight Aloe polysaccharides to treat ovalbumin (OVA)-induced AD in mice. Oral administration of PAG suppressed total and OVA-specific IgE production in sera and decreased the epidermal thickness of skin. Numbers of Ki-67-positive cells were reduced by PAG treatment. Expression levels of tight junction genes, including those that encode ZO-1, Claudin-1 and Claudin-8, were decreased in AD skin lesions, whereas oral administration of PAG partially restored the expression levels of tight junction genes. In addition, IL-4 and IL-17A mRNA transcript levels were reduced in skin lesions after PAG treatment. Taken together, our findings suggest that oral administration of PAG ameliorated AD, normalized tight junction gene expression and suppressed inflammatory cytokines in AD skin.

How does Striga hermonthica Bewitch its hosts?

The common name witchweed synonymous with the Latin name Striga befits the bewitching effects, viz wilting and chlorosis, the parasite inflicts on its hosts long before it emerges and becomes visible above the ground. However, interactions in the rhizosphere between host roots and Striga seedlings are concealed and inscrutable. In vitro experiments revealed that abscisic acid was produced by S. hermonthica seedlings and a considerable portion of the phytohormone was exuded. The phytohormone in the rhizosphere could, at least in part, contribute to the bewitching effects, disrupt host immunity and promote commencement of parasitism.

Antioxidant and anti-osteoporotic effects of anthraquinones and related constituents from the aqueous dissolved Aloe exudates.

In this study, 25 known anthraquinones and related compounds were isolated from aqueous dissolved Aloe exudates. The antioxidant and anti-osteoporotic activities of the isolated compounds were then investigated. Compounds 8, 11, 20, and 23 showed good antioxidant activity based on peroxyl radical-scavenging and reducing capacity assays at a concentration of 10.0 µM. Additionally, compounds 7, 9, 15-16, 18, 21-22 and 24-25 showed potent peroxyl radical-scavenging activities with values ranging from 5.28 to 14.60 at 10.0 µM. Moreover, compounds 8, 11, 15, 20 and 22 exhibited significantly suppressed tartrate-resistant acid phosphatase (TRAP) activity in nuclear factor-κB ligand-activated osteoclastic RAW 264.7 cells, with values of 125.67, 118.54, 127.64, 125.82 and 124.98%, respectively. These results indicate that Aloe is an excellent source of antioxidant and anti-osteoporotic phytochemicals.

Daylily protein constituents of the pollen and stigma a proteomics approach.

This study was aimed at the identification and quantification of the protein components of the pollen grains in parallel with the distal stigmatic tissue of tetraploid cultivars. Proteomes were analyzed using iTRAQ 4plex labeling, peptides separation by online RP-nano-LC and analysis by ESI-MS/MS. Protein identification and quantification were made using the Asparagales database as a reference. A total of 524,037 MS/MS spectra were produced from pollen and stigma samples. From these, a total of 8368 peptides wereidentified corresponding to 994 unique peptides and 432 protein groups. Among them, 128 differentially expressed proteins were retained for further analysis. In absence of the daylily genome availability, we exploited numerous databases and bioinformatics resources to exploring the putative biological functions of these proteins. The profile of differentially expressed proteins suggests an important representation of functions associated to the signalling and response against endogenous and environmental stresses, including several enzymes implicated in the biosynthesis of antibiotics. The abundance in stigma of several structural proteins of the ribosomal sub-units as well as of the core histones suggest that the translation processes and the regulation of gene expression in stigma is a more active mechanism than in pollen. In addition, pollen prioritizes the synthesis of fructose and glucose as opposed to sucrose in stigma as a source of energy. Finally, the modulated proteins in Hemerocallis point to several pathways that give potential clues concerning the molecular mechanisms underlying the functions of the pollen and the stigmatic fluid in daylily reproduction.

Arsenic-hyperaccumulator Pteris vittata efficiently solubilized phosphate rock to sustain plant growth and As uptake.

Phosphorus (P) is one of the most important nutrients for phytoremediation of arsenic (As)-contaminated soils. In this study, we demonstrated that As-hyperaccumulator Pteris vittata was efficient in acquiring P from insoluble phosphate rock (PR). When supplemented with PR as the sole P source in hydroponic systems, P. vittata accumulated 49% and 28% higher P in the roots and fronds than the -P treatment. In contrast, non-hyperaccumulator Pteris ensiformis was unable to solubilize P from PR. To gain insights into PR solubilization by plants, organic acids in plant root exudates were analyzed by HPLC. The results showed that phytic acid was the predominant (>90%) organic acid in P. vittata root exudates whereas only oxalic acid was detected in P. ensiformis. Moreover, P. vittata secreted more phytic acid in -P and PR treatments. Compared to oxalic acid, phytic acid was more effective in solubilizing PR, suggesting that phytic acid was critical for PR utilization. Besides, secretion of phytic acid by P. vittata was not inhibited by arsenate. Our data indicated that phytic acid played an important role in efficient use of insoluble PR by P. vittata, shedding light on using insoluble PR to enhance phytoremediation of As-contaminated soils.

Investigating the potential of Tamarindus indica pectin-chitosan conjugate for reducing recovery period in TNBS induced colitis.

The present study was aimed at exploiting the wound healing applications and tablet coating potential of Tamarindus indica pectin-chitosan (PCH) conjugate for reducing recovery period from TNBS induced colitis. The PCH (60:40, 3% w/v) solution when spray coated followed by drying at 50°C created hydrophobic surface, that may be due to interaction of pectin with chitosan as evident from temperature ramping rheological investigations. Further, the 15% w/v coating was sufficient to prevent Mesalamine (Ma) release in pH 1.2. The AUC and AUMC of PCH coated tablets were 1.98 and 17.69 fold increased as compared to uncoated tablets. A synergistic therapeutic effect of PCH conjugate with Ma was evident from the colon/body weight ratio, clinical activity and damage score. Overall, the findings suggested PCH and Ma (20mg) reduces the recovery period from 5 to 4days with reduction in dose.

Metabolomes of Potato Root Exudates: Compounds That Stimulate Resting Spore Germination of the Soil-Borne Pathogen Spongospora subterranea.

Root exudation has importance in soil chemical ecology influencing rhizosphere microbiota. Prior studies reported root exudates from host and nonhost plants stimulated resting spore germination of Spongospora subterranea, the powdery scab pathogen of potato, but the identities of stimulatory compounds were unknown. This study showed that potato root exudates stimulated S. subterranea resting spore germination, releasing more zoospores at an earlier time than the control. We detected 24 low molecular weight organic compounds within potato root exudates and identified specific amino acids, sugars, organic acids, and other compounds that were stimulatory to S. subterranea resting spore germination. Given that several stimulatory compounds are commonly found in exudates of diverse plant species, we support observations of nonhost-specific stimulation. We provide knowledge of S. subterranea resting spore biology and chemical ecology that may be useful in formulating new disease management strategies.

Variability in Saponin Content, Cancer Antiproliferative Activity and Physicochemical Properties of Concentrated Agave Sap.

Concentrated agave sap (CAS) has gained popularity as an unrefined sweetener. It is obtained by boiling "aguamiel" that contains phytochemicals with diverse bioactivities. Saponins have been the most widely studied agave phytochemicals due to their cancer antiproliferative effect but their concentration may vary due to maturity of the agave plant and collection site. In this study, 18 CAS samples produced in different states of Mexico were analyzed using multivariate methods to determine which physicochemical or phytochemical parameters were responsible for variation. Additionally, extracts with different saponin profiles were tested to determine possible correlations with antiproliferative activity. Total soluble solids, pH, and water activity were similar to those reported for other agave sweeteners. Antioxidant capacity of samples was correlated to browning index. Eleven steroidal saponins were found in CAS samples and they were the main source of variability. Magueyoside B, a kammogenin tetraglycoside, was the most abundant saponin in all samples. With respect to bioactivity, multivariate analysis indicated that magueyoside B and a gentrogenin tetraglycoside were compounds strongly related with bioactivity. CAS from Hidalgo, Puebla, and Veracruz had higher concentration of magueyoside B than from the other kamogenin tetraglycoside found in the samples from other Mexican states. These results could be used as a first approach to characterize and standardize CAS to validate the potential health benefits derived from its consumption.

Striking Diversification of Exudate Profiles in Selected Primula Lineages.

In continuation of previous studies on glandular exudates of Primula, we analyzed eleven so far unstudied species and several populations for exudate composition. Unsubstituted flavone and unusually substituted flavones, normally predominant in Primula exudates, were not detected in all of the analyzed samples. Instead, some species exhibited regular substituted flavonoids, and in some cases, no flavonoids could be detected at all. The detection of a diterpene (1) in P. minima exudates is new to Primula. On basis of MS and NMR, 1 was structurally characterized as ent-kaur-16-en-19-oic acid. Comparative profiling of exudates as performed by HPLC and TLC against authentic markers indicated further the presence of the benzoquinone primin and derivatives in some exudates. Thus, exudates of newly studied species contrast markedly with those analyzed so far. The significance of observed exudate diversification is discussed in view of the phylogeny of derived lineages in European alpine regions.

Properties of Cookies Made with Natural Wax-Vegetable Oil Organogels.

The aim of this study was to examine the feasibility of cookies in which the conventional margarine is replaced with an organogel of vegetable oil (VO) and natural wax. New cookies from VO organogels contain no trans fats and much less saturated fats than cookies made with a conventional margarine. To understand the effects of different kinds of waxes, organogels were prepared from 4 different waxes including sunflower wax (SW), rice bran wax (RBW), beeswax, and candelilla wax and properties of cookie dough and cookie were evaluated. To investigate the effects of different VOs on the properties of cookies, 3 VOs including olive oil, soybean oil and flaxseed oil representing oils rich in oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), respectively, were used. Both the wax and VO significantly affected properties of organogel such as firmness and melting behavior shown in differential scanning calorimetry. The highest firmness of organogel was observed with SW and flaxseed oil. Properties of dough such as hardness and melting behavior were also significantly affected by wax and VO while trends were somewhat different from those for organogels. SW and RBW provided greatest hardnesses to cookie dough. However, hardness, spread factor, and fracturability of cookie containing the wax-VO organogel were not significantly affected by different waxes and VOs. Several cookies made with wax-VO organogels showed similar properties to cookies made with a commercial margarine. Therefore, this study shows the high feasibility of utilization of the organogel technology in real foods such as cookies rich in unsaturated fats.

Study on the release routes of allelochemicals from Pistia stratiotes Linn., and its anti-cyanobacteria mechanisms on Microcystis aeruginosa.

Allelochemicals in Pistia stratiotes Linn. have a strong anti-cyanobacteria effect on Microcystis aeruginosa. To further determine the release routes of allelochemicals in P. stratiotes and understand their anti-cyanobacteria mechanisms, we aimed to systematically investigate the allelopathic effects of leaf leachates, leaf volatilization, root exudates, and residue decomposition of P. stratiotes on M. aeruginosa. The influences of P. stratiotes allelochemicals on the physiological properties of M. aeruginosa were also studied. Root exudates of P. stratiotes exhibited the strongest inhibitory effect on M. aeruginosa growth. The residue decomposition and leaf leachates exhibited a relatively strong inhibitory effect on M. aeruginosa growth. By contrast, the leaf volatilization stimulated M. aeruginosa growth. Therefore, root exudation was determined to be the main release route of allelochemicals from P. stratiotes. The mixed culture experiment of P. stratiotes root exudates and M. aeruginosa showed that the allelochemicals released from root exudation had no effect on the electron transfer of M. aeruginosa photosynthetic system II. However, it reduced the phycocyanin (PC) content and phycocyanin to allophycocyanin (PC/APC) ratio in the photosynthetic system. As the root exudates concentration increased, the electrical conductivity (EC) and superoxide anion radical (O2(*-)) values in the M. aeruginosa culture fluid increased significantly, indicating that the allelochemicals released from the root of P. stratiotes inhibited algae growth by affecting the PC and PC/APC levels in photosynthesis, destroying the cell membrane, and increasing O2(*-) content to result in oxidative damage of M. aeruginosa.

[Identification of chemicals in root exudates of potato and their effects on Rhizoctonia solani].

This study was conducted to identify chemicals in root exudates and their effect on Rhizoctonia solani in potato cropping systems. Root exudates were collected from the fields with 5 years of continuous potato cropping in comparison with rotational cropping of potato and other crops, using in-house made root boxes at the seedling and squaring stages. Chemicals in the root exudates were identified using the GC-MS method. The results showed that glucide concentration was the highest in the root exudates, followed by organic acids. Compared with the rotational cropping, the continuous cropping significantly decreased the glucide content and increased the content of organic acids in the root exudates. The contents of almitic acid in root exudates under continuous cropping was 0.94% at seedling stage and 1.4% at squaring stage, the dibutyl phthalate was 0.15%, whereas under rotational cropping, those values were decreased to 0.15%, 0.2%, and being negligible, respectively. The root exudates promoted the growth of R. solani, especially under continuous potato cropping. The simulation test showed that the palmitic acid and dibutyl phthalate in root exudates could promote the growth of R. solani.

Immunomodulatory properties of Trehala manna decoction and its isolated carbohydrate macromolecules.

ETHNOPHARMACOLOGICAL RELEVANCE: Trehala manna (Shekar tighal) is a cocoon-shaped manna produced by larval activity of Curculionidae family on some Echinops species. In Persian traditional medicine, it is used not only for the treatment of fever and constipation but also for sore throat, influenza and some other viral and bacterial infections which seems to be related to its boosting effects on immune system. The aim of this study was to evaluate immunomodulatory properties of Trehala manna and its isolated polysaccharides. MATERIALS AND METHODS: Several carbohydrate macromolecules were isolated from Trehala manna decoction using solvent-solvent extraction, ion exchange and size-exclusion chromatography. The macromolecules were characterized by gas chromatography-mass spectrometry and spectrophotometric methods. The immunomodulatory effects of Trehala manna decoction and its isolated polysaccharides were evaluated on Jurkat cells at different concentrations using WST-1 reagent. RESULTS: Seven water-soluble polysaccharides were isolated with the structures of rhamnogalacturonan, glucogalacturonan, manno-arabinogalacturonan or homogalacturonan and the molecular weights (MW) of ≤1.67-667 ≤ kDa. Large polysaccharides with MW ≥667 kDa and pectin inhibited the proliferation of Jurkat cells in a dose-dependent manner with the IC50 range of 98.06-429.53 µg/mL. The IC50 for low MW polysaccharides (around 1 kDa) did not show considerable cytotoxicity (IC50>1000 µg/mL), in contrast, they exhibited a dose-dependent enhancement of cell proliferation at concentration range of 15.62-62.50 µg/mL. CONCLUSION: Trehala aqueous decoction and its isolated polysaccharides showed some immunomodulatory effects on Jurkat cell line in a dose-dependent manner and the molecular weight of these polysaccharides also revealed a great impact on their cytotoxic/proliferative properties.

Diterpene Foliar exudates of Blakiella bartsiifolia and phytotoxicity of clerodanes.

Blakiella bartsiifolia (S.F. Blake), an endemic and rare high altitude plant of the northern Andes, appears well adapted to the prevailing harsh environment owing in part to a thick glandular trichome cover. From foliar exudates, two new clerodanes, 15,16-epoxy-2-hydroxy-3,13(16),14-clerodatrien-20-oic acid (bartsiifolic acid) (2) and Z-15,16-dihydroxy-3,13-clerodien-20-oic acid (barthydrolic acid) (3), were isolated in addition to the known junceic acid (1). In addition, three new alicyclic furanoditerpenes: 1,20-epoxy-1,3(20),6(E),10(E),14-phytapentaen-18-methyl-19-oic acid (blakielic acid) (4), 1,20-epoxy- 1,3(20),10(E),14-phytapentaen-18-methyl-19-oic acid (blakifolic acid) (5) and 1,20-epoxy-1,3(20),6,14-phytatetraen-19-methyl-18-oic acid (dihydrocentipedic acid) (6) were obtained in minor quantity. Seed germination and plantlet growth bioassays on Allium cepa and Lactuca sativa to monitor bioactivity during isolation procedures revealed compounds 1-3 with substantial inhibition comparable with synthetic linuron.

Convergence of a specialized root trait in plants from nutrient-impoverished soils: phosphorus-acquisition strategy in a nonmycorrhizal cactus.

In old, phosphorus (P)-impoverished habitats, root specializations such as cluster roots efficiently mobilize and acquire P by releasing large amounts of carboxylates in the rhizosphere. These specialized roots are rarely mycorrhizal. We investigated whether Discocactus placentiformis (Cactaceae), a common species in nutrient-poor campos rupestres over white sands, operates in the same way as other root specializations. Discocactus placentiformis showed no mycorrhizal colonization, but exhibited a sand-binding root specialization with rhizosheath formation. We first provide circumstantial evidence for carboxylate exudation in field material, based on its very high shoot manganese (Mn) concentrations, and then firm evidence, based on exudate analysis. We identified predominantly oxalic acid, but also malic, citric, lactic, succinic, fumaric, and malonic acids. When grown in nutrient solution with P concentrations ranging from 0 to 100 µM, we observed an increase in total carboxylate exudation with decreasing P supply, showing that P deficiency stimulated carboxylate release. Additionally, we tested P solubilization by citric, malic and oxalic acids, and found that they solubilized P from the strongly P-sorbing soil in its native habitat, when the acids were added in combination and in relatively low concentrations. We conclude that the sand-binding root specialization in this nonmycorrhizal cactus functions similar to that of cluster roots, which efficiently enhance P acquisition in other habitats with very low P availability.

An increasing opine carbon bias in artificial exudation systems and genetically modified plant rhizospheres leads to an increasing reshaping of bacterial populations.

To investigate how exudation shapes root-associated bacterial populations, transgenic Arabidopsis thaliana plants that exuded the xenotopic compound octopine at low and high rates were grown in a nonsterile soil. Enumerations of both cultivable and octopine-degrading bacteria demonstrated that the ratios of octopine degraders increased along with octopine concentration. An artificial exudation system was also set up in which octopine was brought at four ratios. The density of octopine-degrading bacteria directly correlated with the input of octopine. Bacterial diversity was analysed by rrs amplicon pyrosequencing. Ensifer and Pseudomonas were significantly more frequently detected in soil amended with artificial exudates. However, the density of Pseudomonas increased as a response to carbon supplementation while that of Ensifer only correlated with octopine concentrations possibly in relation to two opposed colonization strategies of rhizosphere bacteria, that is, copiotrophy and oligotrophy.