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Highlights: [•] Twelve alkaloids have been identified in a geophyte Corydalis bracteata by LC–MS/MS. [•] All parts of C. bracteata accumulate significant amounts of alkaloids. [•] No long-distance transport of alkaloids occurs between plant organs. [•] For the first time, the sites of alkaloid biosynthesis in genus Corydalis are reported. [•] Every organ is capable of biosynthesis of all alkaloids detected in C. bracteata. [Copyright &y& Elsevier]

The morphology, histochemistry and ultrastructure of the glandular trichomes on Empetrum nigrum leaves have been studied and more than a third of the metabolites were identified. Samples of the leaves were fixed and processed for light and electron microscopy. Glandular trichomes are situated on the inner surface of the rolled leaves. They have a clavate head and a short stalk. Histochemical tests and fluorescent microscopy demonstrate differentiated staining of the various cell types in the glandular trichome for proteins, pectins, lipids, tannins and phenylpropanoids. During secretion, the secretory cells contain rough and smooth endoplasmic reticulum, Golgi stacks with large vesicles, diversiform leucoplasts in contact with a reticular sheath and opaque deposits in the vacuoles. There are ultrastructural and functional differences between the secretory cells in the trichome head: synthesis of hydrophilic substances predominately occurs in the upper and middle secretory cells, whereas synthesis of lipophilic compounds takes place in the middle and lower secretory cells. Gas chromatography-mass spectrometry was used to determine the content of metabolites in the methanol extracts from the leaves. Many phenolic compounds (phenolic acids, bibenzyls, catechins, flavanones and flavan-3-ols) as well as several terpenoids were found. Two chalcones (2′,4′-dimethoxydihydrochalcone and 2′,4′,6′-trihydroxydihydrochalcone), one bibenzyl (batatasin III), one flavanone (7-hydroxyflavanone) and 8 terpenoids (including phytol, α-tocopherol, ß-sitosterol, α-amyrin, uvaol, oleanolic acid, ursolic acid and dehydroursolic acid) were identified in E. nigrum leaf extracts. The total yield of phenolic compounds is five to six times higher than the yield of terpenoids. It has been established that chalcones have no hydroxyl groups in ring B whereas bibenzyls have a hydroxyl group in the 3-position in ring B. On the basis of the histochemistry, fluorescent microscopy, ultrastructure and chemical analysis, it may be concluded that synthesis and accumulation of phenolic substances and terpenoids takes place in the clavate glandular trichomes. Secondary metabolites synthesized in the trichomes protect leaf tissues from viruses, bacteria and pathogenic fungi. [ABSTRACT FROM AUTHOR]

Plants known as obligate aerobes developed different mechanisms to overcome the damage incurred under oxygen limitation. One of the survival strategies to have commonly appeared in hydrophytic plants is the escape strategy, which accelerates plant axial organs' growth in order to escape hypoxic conditions as soon as possible. The present study aimed to distinguish the alterations in coleoptile elongation, viability and metabolic profiles in coleoptiles of slow- and fast-growing rice varieties. All the parameters were tested at 3, 5 and 7 days after sowing, to highlight changes during seedling development in normal and submerged conditions. The obtained results indicated that coleoptile elongation correlated with higher resistance to oxygen deprivation. GS-MS-based metabolic profiling indicated that coleoptiles of the fast-growing cultivar accumulated higher amounts of sugar phosphates, disaccharides, fatty acid derivatives and sterols, which are important for maintaining growth, membrane stability and viability. The slow-growing variety was characterized by a greater abundance of carboxylates, including lactate and phosphoric acid, indicating an energy crisis and cytosol acidification, leading to cell damage and low tolerance. Therefore, a metabolomics approach could be used for phenotyping (chemotyping) in the large-scale screening of newly developed varieties with higher tolerance to oxygen deprivation. [ABSTRACT FROM AUTHOR]

In this study, we examined the lipid composition of two strains of the tropical basidiomycete Favolaschia manipularis (Berk.) Teng, which differ in their adaptive potential to high (35 °C) and low (5 °C) temperatures. The results suggest that adaptation to extreme temperatures involves a change in the molecular composition of sterols, in addition to other well-known mechanisms of regulating membrane thickness and fluidity, such as changes in the lipid unsaturation and in the proportion of bilayer- and non-bilayer-forming lipids. It was demonstrated for the first time that adaptation to high temperature stress in fungi is accompanied by the accumulation of 9(11)-dehydroergosterol and ergosterol peroxide. Furthermore, increased thermal plasticity correlates with high storage lipid (triglycerides) content, accumulation of phosphatidic acid in the membrane, and an equal proportion of bilayer and non-bilayer lipids in the membrane. [ABSTRACT FROM AUTHOR]

Background and Aims Decades of research have attempted to elucidate the underlying developmental mechanisms that give rise to the enormous diversity of pollen and spore exines. The organization of the exine starts with the establishment of an elaborate glycocalyx within which the subsequent accumulation of sporopollenin occurs. Ontogenetic studies using transmission electron microscopy of over 30 species from many different groups have shown that the sequence of structures observed during development of the exine corresponds to the sequence of self-assembling micellar mesophases (including liquid crystals) observed at increasing concentrations of surfactants. This suggested that self-assembly plays an important part in exine pattern determination. Some patterns resembling separate layers of spore and pollen grain walls have been obtained experimentally, in vitro , by self-assembly. However, to firmly establish this idea, columellate and granulate exines, the most widespread forms, needed to be simulated experimentally. Methods We used our original method, preparing mixtures of substances analogous to those known to occur in the periplasmic space of developing microspores, then leaving the mixtures undisturbed for specific periods of time to allow the process of self-assembly to occur. We developed our method further by using new substances analogous to those present in the periplasmic space and performing the experiments in a thin layer, more closely resembling the dimensions of the periplasmic space. Key Results The artificial microstructures obtained from our in vitro self-assembly experiments closely resembled the main types of exines, including tectate–columellate, granulate, alveolate and structureless, and permitted comparison with both developing and mature microspore walls. Compared with the previous attempts, we managed to simulate columellate and granulate exines, including lamellate endexine. Conclusions Our results show that simple physico-chemical interactions are able to generate patterns resembling those found in exines, supporting the idea that exine development in nature involves an interplay between the genome and self-assembly. [ABSTRACT FROM AUTHOR]

The barley (Hordeum vulgare L.) chlorina f2 3613 mutant exhibits low photosynthesis and slow growth. This results from downregulation of the levels of photosynthetic antenna proteins caused by the absence of chl b, the major regulator of photosynthetic antennae in land plants. Here, we demonstrate that, when grown in the field in full sunlight, this mutant displays a changed pattern of stomatal responses compared with the parental wild-type cultivar Donaria. However, stomatal regulation of chlorinaf2 3613 plants was restored when plants were placed under a shade cover for several days. The shade cover reduced incident PAR from 2000-2200 mmolm-2 s-1 to 800-880 mmolm-2 s-1 as measured at noon. Contents of ABA, the xanthophyll precursors of ABA biosynthesis and minor antenna proteins, as well as reactive oxygen species levels in stomata and the sensitivity of stomata to exogenously supplied ABA, were determined in leaves of wild-type Donaria and chlorina f2 3613 before and after shading. The results support the view that the restoration of stomatal control in barley chlorina f2 3613 is correlated with an increase in the levels of the minor antenna protein Lhcb6, which has recently been implicated in the enhancement of stomatal sensitivity to ABA in Arabidopsis thaliana (L.) Heynh. [ABSTRACT FROM AUTHOR]

Data on morphology, anatomy, secondary chemistry, ecology, as well as phylogenetic reconstructions based on ITS/5.8S and mtSSU sequence data suggest that “Flavocetraria” minuscula should be transferred to a new monotypic genus Cladocetraria, phylogenetically related to “Cetraria” obtusata and Cetrariella. Cladocetraria minuscula is morphologically similar to Flavocetraria cucullata especially in miniature forms, but differs from this species in having helmet-shaped tips wrapped inside (up-turned) with inconspicuous white pruina, marginal pseudocyphellae in the form of a dotted line, and bacilliform uniformly thickened conidia. Differences from morphologically and phylogenetically related species are discussed. Chemical examination of Cladocetraria minuscula using a liquid chromatography–mass spectrometry assay revealed as previously reported usnic and protolichesterinic acids, as allo-protolichesterinic and lichesterinic acids reported for C. minuscula for the first time. According to presented phylogeny, Flavocetraria cucullata and F. nivalis are only distantly related and belong to different clades within the “Nephromopsis” branch, and must belong to different genera. In this regard, “Flavocetraria” nivalis should be transferred to the monotypic genus Foveolaria. [ABSTRACT FROM AUTHOR]

Background and Aims: Spring geophytes require a period of low temperature for proper flower development but the mechanism that underlies the relationship between cold treatment and flowering remains unknown. The present study aims to compare the developmental anatomy and carbohydrate content of the tuberous geophyte Corydalis bracteata growing under natural winter conditions from 10 to −10 °C (field-grown) and under a mild temperature regime of 18 °C (indoor-grown plants). [ABSTRACT FROM PUBLISHER]

The unique properties of carbon-based nanomaterials, including fullerenol, have attracted great interest in agricultural and environmental applications. Iron (Fe) is an essential micronutrient for major metabolic processes, for which a shortage causes chlorosis and reduces the yield of many crops cultivated worldwide. In the current study, the metabolic responses of Cucumis sativus (a Strategy I plant) to fullerenol treatments were investigated depending on the Fe status of plants. Cucumber plants were grown hydroponically, either with [+FeII (ferrous) and +FeIII (ferric)] or in Fe-free (−FeII and −FeIII) nutrient solution, with (+F) or without (−F) a fullerenol supply. Iron species-dependent effects were observed in either Fe-fed or Fe-starved plants, with alteration of metabolites involved in the metabolism of carbohydrates, amino acids, organic acids, lipophilic compounds. Metabolic perturbations triggered by fullerenol in the FeIII-treated plants were in the opposite kind from those in the FeII-treated plants. Whereas in the FeIII-fed plants, fullerenol activated the metabolisation of carbohydrates and amino acids, in the FeII-fed plants, fullerenol activated the metabolisation of lipophilic compounds and repressed the metabolisation of carbohydrates and amino acids. In FeIII-deficient plants, fullerenol stimulated the metabolism of C3 carboxylates and lipophilic compounds while repressing the metabolism of amino acids, hexoses and dicarboxylates, while in FeII-deficient plants, activations of the metabolism of amino acids and dicarboxylates and repression of sterol metabolism by fullerenol were observed. The results indicated that the valence state of Fe sources is of importance for re-programming metabolome responses in cucumber to fullerenol either in Fe-sufficient or Fe-deficient conditions. These investigations are significant for understanding fullerenol interactions and risk assessment in plants with different Fe statuses. [ABSTRACT FROM AUTHOR]

Arctoparmelia collatolica is described as a species new to science based on morphological, chemical and molecular data. The species is similar to the usnic acid-deficient chemotype of A. centrifuga but differs in the grey-brown to brown upper surface in the central part of the thallus and ivory white to pale brown rhizines. The species contains collatolic acid and its derivatives. Seven secondary lichen substances are reported as new for the genus Arctoparmelia. A key to Arctoparmelia taxa is provided. [ABSTRACT FROM AUTHOR]

Abstract Strategy I plants may respond to iron (Fe) deficiency by rhizosphere acidification. Here, the role of medium pH-values in silicon (Si)-induced mitigation Fe deficiency in Strategy I plants (Cucumis sativus) was investigated, particularly the metabolites regulated by a lack of Fe, using a target metabolomics approach. Plants were grown hydroponically, either with (+Fe) or in Fe-free (−Fe) nutrient solution, with (+Si) or without (−Si) a Si supply. The nutrient solution was adjusted to pH 5.0 or 6.0 and checked daily. Leaf metabolites potentially involved in Fe transport were determined. The typical Fe responses of cucumber (e.g., decrease in leaf chlorophyll, Fe imbalance) were more pronounced when plants were grown at pH 6.0 than 5.0, during long-term Fe deficiency (15 days). Major metabolites up-regulated by Fe deficiency and found in young leaf were succinic, citric and glutamic acids, respectively; their maximal concentrations occurred in Fe-starved plants grown at pH 6.0 without Si supply. Silicon (Si)-induced effects accompanied with alleviation chlorosis symptoms, were most distinct in plants grown at pH 6.0 for an extended period without Fe. Changes in abundance of metabolites specifically up-regulated by a lack of Fe may be manifested before any Si-induced changes in plant Fe content were apparent, suggesting that metabolite responses are highly sensitive to a Fe-dependent signal altered by Si treatments under Fe deficiency. The results indicate that Si supply was more evident when plants were more stressed by an increase in nutrient solution pH under Fe-limited conditions. [ABSTRACT FROM AUTHOR]

Aluminium (Al) is one of the major stressors for plants in acidic soils, negatively affecting plant growth and nutrient balances. Significant efforts have been undertaken to understand mechanisms of Al tolerance in plants. However, little is known of the relevance of iron (Fe) and silicon (Si) nutrition under Al stress conditions. The objectives of this study were to determine whether effects induced by Fe and Si are of importance for limitation of Al moving via xylem in plants ( Cucumis sativus L.). Cucumber plants (cv. Phoenix and Solovei) were grown (i) hydroponically in a complete nutrient solution at pH 4.0, either with (+Fe) or in Fe-free (−Fe) nutrient solution, without (−Si) or with (+Si) supply of Si, without (−Al) or with (+Al) exposure of Al and (ii) in soil. Xylem sap concentrations of Al, Fe and Si were measured. To characterise the pattern of xylem sap transport of Al and Fe, metabolomic changes of root tissues were investigated. Although the growth of cucumber plants was not significantly affected by Al 3+ (Al-tolerant), Al exposure decreased xylem sap Fe (+Fe plants) and increased ferric chelate reductase (FC-R) activity of roots (−Fe plants). On the other hand, Fe supply greatly mitigated the Al-induced increase in xylem sap Al. The ameliorative effect of Fe depended on plant genotypes and was more pronounced in the more Fe-efficient cultivar Phoenix, which presented the highest level of xylem sap Fe. Xylem sap Fe was positively correlated with root serine, succinic and fumaric acids, suggesting that a probable underlying mechanism of Al tolerance might involve the chelation of Fe by biosynthesis of these chelating compounds. The Si-modulated root succinate increase appears to be of great importance for facilitating long-distance transport of Fe, thereby hindering Al transport from roots to shoots. The results highlight for the first time the importance of both Fe and Si supply in plant exclusion of Al under acidic conditions. [ABSTRACT FROM AUTHOR]

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is one of the most abundant targets of the oxidative stress. Oxidation of the enzyme causes its inactivation and the formation of intermolecular disulfide bonds, and leads to the accumulation of GAPDH aggregates and ultimately to cell death. The aim of this work was to reveal the ability of chemicals to break the described above pathologic linkage by inhibiting GAPDH aggregation. Using the model of oxidative stress based on SK-N-SH human neuroblastoma cells treated with hydrogen peroxide, we found that lentivirus-mediated down- or up-regulation of GAPDH content caused inhibition or enhancement of the protein aggregation and respectively reduced or increased the level of cell death. To reveal substances that are able to inhibit GAPDH aggregation, we developed a special assay based on dot ultrafiltration using the collection of small molecules of plant origin. In the first round of screening, five compounds were found to possess anti-aggregation activity as established by ultrafiltration and dynamic light scattering; some of the substances efficiently inhibited GAPDH aggregation in nanomolar concentrations. The ability of the compounds to bind GAPDH molecules was proved by the drug affinity responsive target stability assay, molecular docking and differential scanning calorimetry. Results of experiments with SK-N-SH human neuroblastoma treated with hydrogen peroxide show that two substances, RX409 and RX426, lowered the degree of GAPDH aggregation and reduced cell death by 30%. Oxidative injury was emulated in vivo by injecting of malonic acid into the rat brain, and we showed that the treatment with RX409 or RX426 inhibited GAPDH-mediated aggregation in the brain, reduced areas of the injury as proved by magnetic resonance imaging, and augmented the behavioral status of the rats as established by the “beam walking” test. In conclusion, the data show that two GAPDH binders could be therapeutically relevant in the treatment of injuries stemming from hard oxidative stress. [ABSTRACT FROM AUTHOR]

Diacylglyceryltrimethylhomoserines (DGTS) are betaine-type lipids that are phosphate-free analogs of phosphatidylcholines (PC). DGTS are abundant in some bacteria, algae, primitive vascular plants and fungi. In this study, we report inorganic phosphate (P i ) deficiency-induced DGTS synthesis in the basidial fungus Flammulina velutipes (Curt.: Fr.) Sing. We present results of an expression analysis of the BTA1 gene that codes for betaine lipid synthase and two genes of PC biosynthesis ( CHO2 and CPT1) during phosphate starvation of F. velutipes culture. We demonstrate that Fv BTA1 gene has increased transcript abundance under phosphate starvation. Despite depletion in PC, both CHO2 and CPT1 were determined to have increased expression. We also describe the deduced amino acid sequence and genomic structure of the BTA1 gene in F. velutipes. Phylogenetic relationships between putative orthologs of BTA1 proteins of basidiomycete fungi are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Plant sterols are important multifunctional lipids, which are involved in determining membrane properties. Biophysical characteristics of model lipid and isolated animal membranes with altered sterol component have been intensively studied. In plants however, the precise mechanisms of involvement of sterols in membrane functioning remain unclear. In present work the possible interactions between sterols and other membrane lipids in plant cells were studied. A useful experimental approach for elucidating the roles of sterols in membrane activity is to use agents that specifically bind with endogenous sterols, for example the antibiotic nystatin. Membrane characteristics and the composition of membrane lipids in the roots of wheat (Triticum aestivum L.) seedlings treated with nystatin were analyzed. The application of nystatin greatly increased the permeability of the plasma membrane for ions and SH-containing molecules and decreased the total sterol level mainly as a consequence of a reduction in the amount of β-sitosterol and campesterol. Dynamic light-scattering was used to confirm the in vitro formation of stable complexes between nystatin and β-sitosterol or cholesterol. Sterol depletion was accompanied by a significant rise in total glycoceramide (GlCer) content after 2h treatment with nystatin. Analysis of the GlCer composition using mass spectrometry with electrospray ionization demonstrated that nystatin induced changes in the ratio of molecular species of GlCer. Our results suggest that changes in the sphingolipid composition can contribute to the changes in plasma membrane functioning induced by sterol depletion. [Copyright &y& Elsevier]

The formation of biolayers of various taxonomic and biochemical composition occurs on the rock surfaces under various environmental conditions. The composition of metabolites in various types of biolayers on the marble surface in natural outcrops and urban environment was studied. Metabolome profiling was fulfilled by GC-MS. It was found that communities in urban environment are much less biochemically diverse than in a quarry. The seasonal differences in metabolite network between samples dominate over taxonomic ones in biolayers with predomination of algae and cyanobacteria and in biolayers with predomination of fungi. The biolayers of different stage of soil formation are less susceptible to seasonal variability. [ABSTRACT FROM AUTHOR]

The phytohormone abscisic acid (ABA) plays an important role in plant growth and in response to abiotic stress factors. At the same time, its accumulation in soil can negatively affect seed germination, inhibit root growth and increase plant sensitivity to pathogens. ABA is an inert compound resistant to spontaneous hydrolysis and its biological transformation is scarcely understood. Recently, the strain Rhodococcus sp. P1Y was described as a rhizosphere bacterium assimilating ABA as a sole carbon source in batch culture and affecting ABA concentrations in plant roots. In this work, the intermediate product of ABA decomposition by this bacterium was isolated and purified by preparative HPLC techniques. Proof that this compound belongs to ABA derivatives was carried out by measuring the molar radioactivity of the conversion products of this phytohormone labeled with tritium. The chemical structure of this compound was determined by instrumental techniques including high-resolution mass spectrometry, NMR spectrometry, FTIR and UV spectroscopies. As a result, the metabolite was identified as (4RS)-4-hydroxy-3,5,5-trimethyl-4-[(E)-3-oxobut-1-enyl]cyclohex-2-en-1-one (dehydrovomifoliol). Based on the data obtained, it was concluded that the pathway of bacterial degradation and assimilation of ABA begins with a gradual shortening of the acyl part of the molecule. [ABSTRACT FROM AUTHOR]

Basidiomycete fungus Serpula lacrymans is one of the most dangerous indoor fungus causing dry rot of timber. The physiology of this fungus deserves more attention as a basis for development of methods of dry rot treatment. We observed an increase in the freezing resistance of S. lacrymans after pre-cultivation of mycelia at elevated temperatures. To examine the biochemical mechanisms underlying this phenomenon the lipid composition and metabolite profiling of mycelia subjected to freezing and thawing were investigated. An analysis is made of the growth rate and metabolism of “daughter” cultures derived from a frozen mycelia. According to the results, sphingolipids and water-soluble metabolites such as mannitol, glycerol, sugar alcohols, some amino- and organic acids are able to function as protective compounds providing a cross-resistance between heat shock and freeze–thaw stress in S. lacrymans. [ABSTRACT FROM AUTHOR]