Endophytic non-pathogenic Fusarium oxysporum reorganizes the cell wall in flax seedlings

Introduction

Flax (Linum usitatissimum) is a crop producing valuable products like seeds and fiber. However, its cultivation faces challenges from environmental stress factors and significant yield losses due to fungal infections. The major threat is Fusarium oxysporum f.sp lini, causing fusarium wilt of flax. Interestingly, within the Fusarium family, there are non-pathogenic strains known as biocontrols, which protect plants from infections caused by pathogenic strains. When exposed to a non-pathogenic strain, flax exhibits defense responses similar to those seen during pathogenic infections. This sensitization process activates immune reactions, preparing the plant to better combat potential pathogenic strains. The plant cell wall is crucial for defending against pathogens. It serves as the primary barrier, blocking pathogen entry into plant cells.

Methods

The aim of the study was to investigate the effects of treating flax with a non-pathogenic Fusarium oxysporum strain, focusing on cell wall remodeling. The infection's progress was monitored by determining the fungal DNA content and microscopic observation. The plant defense response was confirmed by an increase in the level of Pathogenesis-Related (PR) genes transcripts. The reorganization of flax cell wall during non-pathogenic Fusarium oxysporum strain infection was examined using Infrared spectroscopy (IR), determination of cell wall polymer content, and analysis of mRNA level of genes involved in their metabolism.

Results and discussion

IR analysis revealed reduced cellulose content in flax seedlings after treatment with Fo47 and that the cellulose chains were shorter and more loosely bound. Hemicellulose content was also reduced but only after 12h and 36h. The total pectin content remained unchanged, while the relative share of simple sugars and uronic acids in the pectin fractions changed over time. In addition, a dynamic change in the level of methylesterification of carboxyl groups of pectin was observed in flax seedlings treated with Fo47 compared to untreated seedlings. The increase in lignin content was observed only 48 hours after the treatment with non-pathogenic Fusarium oxysporum. Analysis of mRNA levels of cell wall polymer metabolism genes showed significant changes over time in all analyzed genes. In conclusion, the research suggests that the rearrangement of the cell wall is likely one of the mechanisms behind flax sensitization by the non-pathogenic Fusarium oxysporum strain. Understanding these processes could help in developing strategies to enhance flax's resistance to fusarium wilt and improve its overall yield and quality.

Transcriptome profiling of flax plants exposed to a low-frequency alternating electromagnetic field

All living organisms on Earth evolved in the presence of an electromagnetic field (EMF), adapted to the environment of EMF, and even learned to utilize it for their purposes. However, during the last century, the Earth's core lost its exclusivity, and many EMF sources appeared due to the development of electricity and electronics. Previous research suggested that the EMF led to changes in intercellular free radical homeostasis and further altered the expression of genes involved in plant response to environmental stresses, inorganic ion transport, and cell wall constituent biosynthesis. Later, CTCT sequence motifs in gene promoters were proposed to be responsible for the response to EMF. How these motifs or different mechanisms are involved in the plant reaction to external EMF remains unknown. Moreover, as many genes activated under EMF treatment do not have the CTCT repeats in their promoters, we aimed to determine the transcription profile of a plant exposed to an EMF and identify the genes that are directly involved in response to the treatment to find the common denominator of the observed changes in the plant transcriptome.

Overexpression of Bacterial Beta-Ketothiolase Improves Flax (Linum usitatissimum L.) Retting and Changes the Fibre Properties

Beta-ketothiolases are involved in the beta-oxidation of fatty acids and the metabolism of hormones, benzenoids, and hydroxybutyrate. The expression of bacterial beta-ketothiolase in flax (Linum usitatissimum L.) results in an increase in endogenous beta-ketothiolase mRNA levels and beta-hydroxybutyrate content. In the present work, the effect of overexpression of beta-ketothiolase on retting and stem and fibre composition of flax plants is presented. The content of the components was evaluated by high-performance liquid chromatography, gas chromatography–mass spectrometry, Fourier-transform infrared spectroscopy, and biochemical methods. Changes in the stem cell walls, especially in the lower lignin and pectin content, resulted in more efficient retting. The overexpression of beta-ketothiolase reduced the fatty acid and carotenoid contents in flax and affected the distribution of phenolic compounds between free and cell wall-bound components. The obtained fibres were characterized by a slightly lower content of phenolic compounds and changes in the composition of the cell wall. Based on the IR analysis, we concluded that the production of hydroxybutyrate reduced the cellulose crystallinity and led to the formation of shorter but more flexible cellulose chains, while not changing the content of the cell wall components. We speculate that the changes in chemical composition of the stems and fibres are the result of the regulatory properties of hydroxybutyrate. This provides us with a novel way to influence metabolic composition in agriculturally important crops.

Abscisic Acid-Defensive Player in Flax Response to Fusarium culmorum Infection

Fusarium culmorum is a ubiquitous soil pathogen with a wide host range. In flax (Linum ussitatissimum), it causes foot and root rot and accumulation of mycotoxins in flax products. Fungal infections lead to huge losses in the flax industry. Moreover, due to mycotoxin accumulation, flax products constitute a potential threat to the consumers. We discovered that the defense against this pathogen in flax is based on early oxidative burst among others. In flax plants infected with F. culmorum, the most affected genes are connected with ROS production and processing, callose synthesis and ABA production. We hypothesize that ABA triggers defense mechanism in flax and is a significant player in a successful response to infection.

Linseed Silesia, Diverse Crops for Diverse Diets. New Solutions to Increase Dietary Lipids in Crop Species

The aim of the work was to compare the new variety of oil flax (Silesia) with already cultivated varieties in terms of plant productivity, oil content, fatty acid composition and significant secondary metabolites. The analyzed linseed varieties are characterized by low (Linola), medium (Silesia) and high (Szafir) content of omega-3 fatty acids. Special attention was paid to the quality of the oil and the characteristics that determine its stability (reduction of susceptibility to oxidation). A number of antioxidant compounds of secondary metabolism (simple phenols, phenolic acids, flavonoids, tannins) were identified in the linseed oils. All of these compounds can affect lipid oxidation by a mechanism that attenuates initiating radicals such as hydroxyl or forms an oxidizing primary product such as peroxides. Chelation of metal ions may also be involved in lipid oxidation. We propose a mechanism that encompasses all these processes and facilitates understanding of the complex relationships between them. The general thesis is that the ratio of polyunsaturated fatty acids is associated with a better metabolic state of flaxseed, and thus with a higher nutritional value. In addition, we find a number of specialized secondary metabolites characteristic of the flax studied, which could be useful for chemotaxonomy.

Expression of the Tyrosine Hydroxylase Gene from Rat Leads to Oxidative Stress in Potato Plants

Catecholamines are biogenic aromatic amines common among both animals and plants. In animals, they are synthesized via tyrosine hydroxylation, while both hydroxylation or decarboxylation of tyrosine are possible in plants, depending on the species, though no tyrosine hydroxylase-a counterpart of the animal enzyme-has been identified yet. It is known that in potato plants, it is the decarboxylation of tyrosine that leads to catecholamine production. In this paper, we present the effects of the induction of an alternative route of catecholamine production by introducing the tyrosine hydroxylase gene from rat. We demonstrate that an animal system can be used by the plant. However, it does not function to synthesize catecholamines. Instead, it leads to elevated reactive oxygen species content and a constant stress condition in the plant, which responds with elevated antioxidant levels and improved resistance to infection.

Metabolism of the Cyanogenic Glucosides in Developing Flax: Metabolic Analysis, and Expression Pattern of Genes

Cyanogenic glucosides (CG), the monoglycosides linamarin and lotaustralin, as well as the diglucosides linustatin and neolinustatin, have been identified in flax. The roles of CG and hydrogen cyanide (HCN), specifically the product of their breakdown, differ and are understood only to a certain extent. HCN is toxic to aerobic organisms as a respiratory inhibitor and to enzymes containing heavy metals. On the other hand, CG and HCN are important factors in the plant defense system against herbivores, insects and pathogens. In this study, fluctuations in CG levels during flax growth and development (using UPLC) and the expression of genes encoding key enzymes for their metabolism (valine N-monooxygenase, linamarase, cyanoalanine nitrilase and cyanoalanine synthase) using RT-PCR were analyzed. Linola cultivar and transgenic plants characterized by increased levels of sulfur amino acids were analyzed. This enabled the demonstration of a significant relationship between the cyanide detoxification process and general metabolism. Cyanogenic glucosides are used as nitrogen-containing precursors for the synthesis of amino acids, proteins and amines. Therefore, they not only perform protective functions against herbivores but are general plant growth regulators, especially since changes in their level have been shown to be strongly correlated with significant stages of plant development.

Fusarium oxysporum infection activates the plastidial branch of the terpenoid biosynthesis pathway in flax, leading to increased ABA synthesis

Upregulation of the terpenoid pathway and increased ABA content in flax upon Fusarium infection leads to activation of the early plant's response (PR genes, cell wall remodeling, and redox status). Plants have developed a number of defense strategies against the adverse effects of fungi such as Fusarium oxysporum. One such defense is the production of antioxidant secondary metabolites, which fall into two main groups: the phenylpropanoids and the terpenoids. While functions and biosynthesis of phenylpropanoids have been extensively studied, very little is known about the genes controlling the terpenoid synthesis pathway in flax. They can serve as antioxidants, but are also substrates for a plethora of different compounds, including those of regulatory functions, like ABA. ABA's function during pathogen attack remains obscure and often depends on the specific plant-pathogen interactions. In our study we showed that in flax the non-mevalonate pathway is strongly activated in the early hours of pathogen infection and that there is a redirection of metabolites towards ABA synthesis. The elevated synthesis of ABA correlates with flax resistance to F. oxysporum, thus we suggest ABA to be a positive regulator of the plant's early response to the infection.

DNA Methylation Profile of β-1,3-Glucanase and Chitinase Genes in Flax Shows Specificity Towards Fusarium Oxysporum Strains Differing in Pathogenicity

Most losses in flax (Linum usitatissimum L.) crops are caused by fungal infections. The new epigenetic approach to improve plant resistance requires broadening the knowledge about the influence of pathogenic and non-pathogenic Fusarium oxysporum strains on changes in the profile of DNA methylation. Two contrasting effects on the levels of methylation in flax have been detected for both types of Fusarium strain infection: Genome-wide hypermethylation and hypomethylation of resistance-related genes (β-1,3-glucanase and chitinase). Despite the differences in methylation profile, the expression of these genes increased. Plants pretreated with the non-pathogenic strain memorize the hypomethylation pattern and then react more efficiently upon pathogen infection. The peak of demethylation correlates with the alteration in gene expression induced by the non-pathogenic strain. In the case of pathogen infection, the expression peak lags behind the gene demethylation. Dynamic changes in tetramer methylation induced by both pathogenic and non-pathogenic Fusarium strains are dependent on the ratio between the level of methyltransferase and demethylase gene expression. Infection with both Fusarium strains suppressed methyltransferase expression and increased the demethylase (demeter) transcript level. The obtained results provide important new information about changes in methylation profile and thus expression regulation of pathogenesis-related genes in the flax plant response to stressors.

Temporal biosynthesis of flavone constituents in flax growth stages

Previous studies showed that chalcone synthase (chs) silencing in flax (Linum usitatisimum) induces a signal transduction cascade that leads to extensive modification of plant metabolism. Result presented in the current study, performed on field grown flax plants - (across the whole vegetation period) demonstrates that, in addition to its role in tannin and lignin biosynthesis, the chs gene also participates in the regulation of flavone biosynthesis during plant growth. Apigenin and luteolin glycosides constitute the flavones, the major group of flavonoids in flax. Alterations in their levels correlate with plant growth, peaking at the flower initiation stage. Suppression of chs gene expression causes significant changes in the ratio of flavone constituents at the early stage of flax growth. A significant correlation between flavonoid 3'-hydroxylase (F3'H) gene expression and accumulation of luteolin glycosides has been found, indicating that flavone biosynthesis during flax growth and development is regulated by temporal expression of this gene. The lack of such a correlation between the flavone synthase (FNS) gene and flavone accumulation in the course of plant growth suggests that the main route of flavone biosynthesis is mediated by eriodictyol. This is the first report indicating the ratio of flavone constituents as a potent marker of flax growth stages and temporal expression of F3'H, the key gene of their biosynthesis.

Impact of fabrics from transgenic flax on cultures of skin cells

BACKGROUND

The development of a new type of wound dressing material that can support skin regeneration is an important challenge to improve treatment of chronic, non-healing wounds.

OBJECTIVES

The objective of this study was to compare the impact of flax fabrics from transgenic plants overexpressing phenolic acids and flavonoids (W92) and polyhydroxybutyrate (M48), as well as fabric from non-transgenic plant (Nike) on cultures of human skin cells.

MATERIAL AND METHODS

Flax fabric pieces as well as water extracts from the fabrics were co-cultured with human skin cells: keratinocytes, fibroblasts, dermal microvascular endothelial cells, and with monocytoid cell line (THP1) for 48 h. Cell viability and proliferation were assessed with the sulforhodamine B colorimetric assay. Intracellular reactive oxygen species (ROS) was estimated with the 2'7 dichlorodihydrofluorescein diacetate (DCFH-DA) oxidation method. Endothelial cell migration was measured with the scratch assay. The results were compared with the multi-criteria analysis (MCA) procedure.

RESULTS

Tested flax fabrics released flavonoids and polyhydroxybutyrate to cell culture media, as it was determined by means of the high performance liquid chromatography (HPLC) method. Fabrics from transgenic plants W92 and M48 promoted proliferation of keratinocytes and fibroblasts. Water extracts from flax fabric diminished the proliferation of monocytoid cells, decreased oxidative burst in activated THP1 cells and accelerated the velocity of dermal microvascular cell migration. The MCA proved that the sum of beneficial effects estimated in human skin cell cultures was higher (by 47% and by 34% with W92 and M48, respectively) than that of non-transgenic flax fabric (Nike).

CONCLUSIONS

The W92 and M48 fabrics should be further studied as candidates for elaboration of new types of bandages, able to improve skin wound healing.

Unique chromoplast organisation and carotenoid gene expression in carotenoid-rich carrot callus

MAIN CONCLUSION

The new model orange callus line, similar to carrot root, was rich in carotenoids due to altered expression of some carotenogenesis-associated genes and possessed unique diversity of chromoplast ultrastructure. Callus induced from carrot root segments cultured in vitro is usually pale yellow (p-y) and poor in carotenoids. A unique, non-engineered callus line of dark orange (d-o) colour was developed in this work. The content of carotenoid pigments in d-o callus was at the same level as in an orange carrot storage root and nine-fold higher than in p-y callus. Carotenoids accumulated mainly in abundant crystalline chromoplasts that are also common in carrot root but not in p-y callus. Using transmission electron microscopy, other types of chromoplasts were also found in d-o callus, including membranous chromoplasts rarely identified in plants and not observed in carrot root until now. At the transcriptional level, most carotenogenesis-associated genes were upregulated in d-o callus in comparison to p-y callus, but their expression was downregulated or unchanged when compared to root tissue. Two pathway steps were critical and could explain the massive carotenoid accumulation in this tissue. The geranylgeranyl diphosphate synthase gene involved in the biosynthesis of carotenoid precursors was highly expressed, while the β-carotene hydroxylase gene involved in β-carotene conversion to downstream xanthophylls was highly repressed. Additionally, paralogues of these genes and phytoene synthase were differentially expressed, indicating their tissue-specific roles in carotenoid biosynthesis and metabolism. The established system may serve as a novel model for elucidating plastid biogenesis that coincides with carotenogenesis.

Expression of heterologous lycopene β-cyclase gene in flax can cause silencing of its endogenous counterpart by changes in gene-body methylation and in ABA homeostasis mechanism

Previously we described flax plants with expression of Arabidopsis lycopene β-cyclase (lcb) gene in which decreased expression of the endogenous lcb and increased resistance to fungal pathogen was observed. We suggested that co-suppression was responsible for the change. In this study we investigated the molecular basis of the observed effect in detail. We found that methylation changes in the Lulcb gene body might be responsible for repression of the gene. Treatment with azacitidine (DNA methylation inhibitor) confirmed the results. Moreover, we studied how the manipulation of carotenoid biosynthesis pathway increased ABA level in these plants. We suggest that elevated ABA levels may be responsible for the increased resistance of the flax plants to pathogen infection through activation of chitinase (PR gene).

The effects of seed from Linum usitatissimum cultivar with increased phenylpropanoid compounds and hydrolysable tannin in a high cholesterol-fed rabbit

Background

Dietary fat is considered one of the most important factors associated with blood lipid metabolism and plays a significant role in the cause and prevention of atherosclerosis that has been widely accepted as an inflammatory disease of the vascular system. The aim of the present study was to evaluate the effect of genetically modified flaxseed (W86) rich in phenylpropanoid compounds and hydrolysable tannin in high cholesterol-induced atherosclerosis rabbit models compared to parental cultivar Linola.

Methods

Twenty-Eight White New Zealand white rabbits aged 6 months were randomly divided into four groups, control group, high cholesterol group (10 g/kg), Linola flaxseed group (100 g/kg) and W86 flaxseed group (100 g/kg). The rabbits were fed a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, hematological values, total antioxidative status and superoxide dismutase activity in serum were determined. Moreover, body weight and feed intake were measured after sixth and tenth weeks. After each stage of the experiment atherogenic indexes (non-HDL-C/HDL-C, LDL-C/HDL-C, and atherogenic index of plasma) was calculated.

Results

The intake of a dyslipidaemic diet negatively influenced lipid profile in rabbits at the 10 weeks of feeding. W86 flaxseed significantly decreased total cholesterol, LDL-C, VLDL-C and TG serum levels in cholesterolemic rabbits compared with parental Linola after 10 weeks. Atherogenic indexes decreased over time with a significant difference between the diets and they were the best for W86 flaxseed. Similarly, the experimental addition of W86 significantly decreased atherogenic predictors such as heterophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the mean platelet volume-to-lymphocyte ratio. In rabbits, W86 flaxseed increased the activity of superoxide dismutase and total antioxidative status compared to Linola.

Conclusions

Results of the presented study suggest that the addition of W86 flaxseed alleviate serum lipid changes in high cholesterolemic diet-administered rabbits. W86 flaxseed significantly reduced atherogenic indexes, as compared with the Linola and indicate that W86 flaxseed more effectively red CVD risk factors during hypercholesterolemia. Moreover, the presented result suggested that W86 flaxseed can be a part of a heart-healthy and antiatherogenic diet for the human.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0726-4) contains supplementary material, which is available to authorized users.

The cinnamyl alcohol dehydrogenase family in flax: Differentiation during plant growth and under stress conditions

Cinnamyl alcohol dehydrogenase (CAD), which catalyzes the reduction of cinnamaldehydes to their alcohol derivatives, is represented by a large family of proteins. The aim of the study was to identify the CAD isoforms in flax (Linum usitatissimum L.) - LuCADs - and to determine their specificity to enhance knowledge of the mechanisms controlling cell wall lignification in flax under environmental stresses. On the basis of genome-wide analysis, we identified 15 isoforms (one in two copies) belonging to three major classes of the CAD protein family. Their specificity was determined at the transcriptomic level in different tissues/organs, under Fusarium infection and abiotic stresses. Considering the function of particular LuCADs, it was established that LuCAD1 and 2 belong to Class I and they take part in the lignification of maturing stem and in the response to cold and drought stress. The Class II members LuCAD3, LuCAD4, LuCAD5 and LuCAD6 play various roles in flax being putatively responsible for lignin synthesis in different organs or under certain conditions. The obtained results indicate that within Class II, LuCAD6 was the most abundant in seedlings and maturing stems, LuCAD3 in leaves, and LuCAD4 in stems. Comparative analysis showed that expression of LuCAD genes in roots after F. oxysporum infection had the greatest contribution to differentiation of LuCAD expression patterns. Surprisingly, most of the analyzed LuCAD isoforms had reduced expression after pathogen infection. The decrease in mRNA level was primarily observed for LuCAD6 and LuCAD4, but also LuCAD1 and 8. However, the induction of LuCAD expression was mostly characteristic for Class I LuCAD1 and 2 in leaves. For cold stress, a clear correlation with phylogenic class membership was observed. Low temperatures caused induction of CAD isoforms belonging to Class I and repression of LuCADs from Class III.

V79 Fibroblasts Are Protected Against Reactive Oxygen Species by Flax Fabric

Chinese hamster pulmonary fibroblasts (V79 cells) pre-treated with flax fabrics derived from non-modified or genetically engineered flax fibres and treated with H₂O₂ revealed a markedly lower level of intracellular reactive oxygen species (ROS) than control, non-pre-treated cells. The fabrics were prepared from fibres derived from two kinds of transgenic plants: W92 plants, which overproduce flavonoids, and M type plants, which produce hydroxybutyrate polymer in their vascular bundles and thus in fibres. Incubating the V79 cells with the flax fabrics prior to H₂O₂ treatment also reduced the amount of DNA damage, as established using the comet assay (also known as alkaline single-cell gel electrophoresis) and pulsed-field electrophoresis of intact cellular DNA. Selected gene expression analysis revealed the activator impact of fabrics on the apoptotic (BCL2 family, caspases) gene expression. This promoting activity was also detected for histone acetyltransferase (HAT; MYST2) gene expression. The flax fabric derived from both GM flax plants exhibited a protective effect against oxidative stress and ROS-mediated genotoxic damage, but the W92 fabric was the strongest. It is thus suggested that these fabrics might be useful as a basis for new biomedical products (e.g. wound dressings) that actively protect cells against inflammation and degeneration.

Oligodeoxynucleotides Can Transiently Up- and Downregulate CHS Gene Expression in Flax by Changing DNA Methylation in a Sequence-Specific Manner

Chalcone synthase (CHS) has been recognized as an essential enzyme in the phenylpropanoid biosynthesis pathway. Apart from the leading role in the production of phenolic compounds with many valuable biological activities beneficial to biomedicine, CHS is well appreciated in science. Genetic engineering greatly facilitates expanding knowledge on the function and genetics of CHS in plants. The CHS gene is one of the most intensively studied genes in flax. In our study, we investigated engineering of the CHS gene through genetic and epigenetic approaches. Considering the numerous restrictions concerning the application of genetically modified (GM) crops, the main purpose of this research was optimization of the plant's modulation via epigenetics. In our study, plants modified through two methods were compared: a widely popular agrotransformation and a relatively recent oligodeoxynucleotide (ODN) strategy. It was recently highlighted that the ODN technique can be a rapid and time-serving antecedent in quick analysis of gene function before taking vector-mediated transformation. In order to understand the molecular background of epigenetic variation in more detail and evaluate the use of ODNs as a tool for predictable and stable gene engineering, we concentrated on the integration of gene expression and gene-body methylation. The treatment of flax with a series of short oligonucleotides homologous to a different part of CHS gene isoforms revealed that those directed to regulatory gene regions (5'- and 3'-UTR) activated gene expression, directed to non-coding region (introns) caused gen activity reduction, while those homologous to a coding region may have a variable influence on its activity. Gene expression changes were accompanied by changes in its methylation status. However, only certain (CCGG) motifs along the gene sequence were affected. The analyzed DNA motifs of the CHS flax gene are more accessible for methylation when located within a CpG island. The methylation motifs also led to rearrangement of the nucleosome location. The obtained results suggest high specificity of ODN action and establish a potential valuable alternative for improvement of crops.

FLAX OIL FROM TRANSGENIC LINUM USITATISSIMUM SELECTIVELY INHIBITS IN VITRO PROLIFERATION OF HUMAN CANCER CELL LINES

Emulsions made of oils from transgenic flaxseeds significantly decreased in vitro proliferation of six tested human cancer cell lines in 48-h cultures, as assessed with the standard sulforhodamine assay. However, the emulsions also increased proliferation rate of normal human dermal fibroblasts and, to a lower extend, of keratinocytes. Both inhibition of in vitro proliferation of human cancer cell lines and stimulation of proliferation of normal dermal fibroblasts and keratinocytes were especially strong with the emulsion type B and with emulsion type M. Oils from seeds of transgenic flax type B and M should be considered as valuable adjunct to standard cytostatic therapy of human cancers and also could be applied to improve the treatment of skin lesions in wound healing.

IMPACT OF FABRICS FROM TRANSGENIC FLAX PLANT ON HUMAN DERMAL FIBROBLASTS IN VITRO PROLIFERATION

Previously it was documented that transgenic flax plants, which contained an increased level of polyphenolic compounds, significantly improved healing of skin wounds lesions. In order to recognize mechanisms of beneficial action of transgenic flax fabrics on wound healing, in the present study the impact of flax fabric pieces/cuts from three types of transgenic flax on normal human dermal fibroblasts primary culture (NHDF) was investigated. NHDF cell cultures were exposed for 48 h to specific area of flax fabric cuts, made from M50, B 14 and M50+B14 (intertwined fibers of M and B), or parallely, extracts from fibers of the tested flax materials to cell culture medium. Cultures were inspected for cell viability, proliferation, cell cycle changes and for their resistance to oxidative stress (consecutive addition of H₂,O₂, to harvested cell cultures). None of the tested flax fabrics were cytotoxic to fibroblast cultures and also did not increase significantly a frequency of apoptotic cells in cultures. In the comet assay, the tested flax fabrics revealed significant protective effect on DNA damage ciused by addition of H₂0₂ to the cultures at the end of incubation time. Fabrics from transgenic flax significantly enhanced fibroblasts proliferation in vitro estimated with the SRB test. Flow cytometric analysis revealed higher frequency of cells in the S phase, in the presence of transgenic flax fabrics. Fabrics from B14 and M50+B14 flax are the most potent activators of NHDF cells in applied in vityo tests, hence they could be recommended for elaboration of new type bandage, able to improve skin wound healing.

A new genotype of flax (Linum usitatissimum L.) with decreased susceptibility to fat oxidation: consequences to hematological and biochemical profiles of blood indices

BACKGROUND

Flaxseed is an alternative to marine products that provide the traditional dietary sources of ω-fatty acids. A new genotype of flax, W92, is rich in natural antioxidants as well as having a reduced content of α-linolenic acid and therefore shows decreased susceptibility to fat oxidation. The objective of this study was to evaluate the effect of a diet supplemented with W92 flaxseed on hematological and biochemical blood indices.

RESULTS

A positive impact of diet with the addition of flaxseed was observed on erythrocyte indices, including red blood cell (RBC), hematocrit (HCT), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) values. There were no significant differences for white blood cell (WBC), total protein and glucose values. Aspartate aminotransferase and alanine aminotransferase estimations in serum were also carried out and no obvious toxicity to the liver was shown. Moreover, a lipid profile was performed in serum samples and a decrease in total cholesterol and low-density lipoprotein cholesterol (LDL-C), accompanied by an increase in high-density lipoprotein cholesterol (HDL-C), was observed in rabbits fed flaxseed diets.

CONCLUSION

Based on the results obtained, it appeared that the inclusion of a new genetically modified type of flaxseed in the diet altered cholesterol metabolism and could reduce the possibility of cardiovascular diseases. Diet enrichment with W92 flaxseed may be a solution to the health issues that are a result of improper diet in humans and animals. © 2016 Society of Chemical Industry.

Flavonoid C-glucosides Derived from Flax Straw Extracts Reduce Human Breast Cancer Cell Growth In vitro and Induce Apoptosis

Flax straw of flax varieties that are grown for oil production is a by product which represents a considerable biomass source. Therefore, its potential application for human use is of high interest. Our research has revealed that flax straw is rich in flavonoid C-glucosides, including vitexin, orientin, and isoorientin. The objective of this study was to evaluate the cytotoxicity and possible proapoptotic effect of flax straw derived C-glucosides of flavonoids in the human breast adenocarcinoma cell line (MCF-7). The effects of flax straw derived flavonoid C-glucosides on cell proliferation of MCF-7 cells were evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and sulforhodamine B assays. The expression of apoptosis-related genes was assessed by real-time PCR. Our data revealed that flax C-glucosides as well as pure compounds are cytotoxic toward MCF-7 cells and inhibit their proliferation. Moreover, the induction of apoptosis was correlated with the changes in the mRNA level of pro-apoptotic genes. Increased expression of bax and caspase-7, -8, and -9 and decreased mRNA expression of bcl-2 was observed, whereas the mRNA levels of p53 and mdm2 were not altered. These results clearly demonstrated that flax straw metabolites effectively induced growth inhibition and apoptosis in human breast adenocarcinoma cells.

Evaluation of the significance of cell wall polymers in flax infected with a pathogenic strain of Fusarium oxysporum

BACKGROUND

Fusarium oxysporum infection leads to Fusarium-derived wilt, which is responsible for the greatest losses in flax (Linum usitatissimum) crop yield. Plants infected by Fusarium oxysporum show severe symptoms of dehydration due to the growth of the fungus in vascular tissues. As the disease develops, vascular browning and leaf yellowing can be observed. In the case of more virulent strains, plants die. The pathogen's attack starts with secretion of enzymes degrading the host cell wall. The main aim of the study was to evaluate the role of the cell wall polymers in the flax plant response to the infection in order to better understand the process of resistance and develop new ways to protect plants against infection. For this purpose, the expression of genes involved in cell wall polymer metabolism and corresponding polymer levels were investigated in flax seedlings after incubation with Fusarium oxysporum.

RESULTS

This analysis was facilitated by selecting two groups of genes responding differently to the infection. The first group comprised genes strongly affected by the infection and activated later (phenylalanine ammonia lyase and glucosyltransferase). The second group comprised genes which are slightly affected (up to five times) and their expression vary as the infection progresses. Fusarium oxysporum infection did not affect the contents of cell wall polymers, but changed their structure.

CONCLUSION

The results suggest that the role of the cell wall polymers in the plant response to Fusarium oxysporum infection is manifested through changes in expression of their genes and rearrangement of the cell wall polymers. Our studies provided new information about the role of cellulose and hemicelluloses in the infection process, the change of their structure and the expression of genes participating in their metabolism during the pathogen infection. We also confirmed the role of pectin and lignin in this process, indicating the major changes at the mRNA level of lignin metabolism genes and the loosening of the pectin structure.

The Potential of Plant Phenolics in Prevention and Therapy of Skin Disorders

Phenolic compounds constitute a group of secondary metabolites which have important functions in plants. Besides the beneficial effects on the plant host, phenolic metabolites (polyphenols) exhibit a series of biological properties that influence the human in a health-promoting manner. Evidence suggests that people can benefit from plant phenolics obtained either by the diet or through skin application, because they can alleviate symptoms and inhibit the development of various skin disorders. Due to their natural origin and low toxicity, phenolic compounds are a promising tool in eliminating the causes and effects of skin aging, skin diseases, and skin damage, including wounds and burns. Polyphenols also act protectively and help prevent or attenuate the progression of certain skin disorders, both embarrassing minor problems (e.g., wrinkles, acne) or serious, potentially life-threatening diseases such as cancer. This paper reviews the latest reports on the potential therapy of skin disorders through treatment with phenolic compounds, considering mostly a single specific compound or a combination of compounds in a plant extract.

Chalcone Synthase (CHS) Gene Suppression in Flax Leads to Changes in Wall Synthesis and Sensing Genes, Cell Wall Chemistry and Stem Morphology Parameters

The chalcone synthase (CHS) gene controls the first step in the flavonoid biosynthesis. In flax, CHS down-regulation resulted in tannin accumulation and reduction in lignin synthesis, but plant growth was not affected. This suggests that lignin content and thus cell wall characteristics might be modulated through CHS activity. This study investigated the possibility that CHS affects cell wall sensing as well as polymer content and arrangement. CHS-suppressed and thus lignin-reduced plants showed significant changes in expression of genes involved in both synthesis of components and cell wall sensing. This was accompanied by increased levels of cellulose and hemicellulose. CHS-reduced flax also showed significant changes in morphology and arrangement of the cell wall. The stem tissue layers were enlarged averagely twofold compared to the control, and the number of fiber cells more than doubled. The stem morphology changes were accompanied by reduction of the crystallinity index of the cell wall. CHS silencing induces a signal transduction cascade that leads to modification of plant metabolism in a wide range and thus cell wall structure.

Methyl Salicylate Level Increase in Flax after Fusarium oxysporum Infection Is Associated with Phenylpropanoid Pathway Activation

Flax (Linum usitatissimum) is a crop plant valued for its oil and fiber. Unfortunately, large losses in cultivation of this plant are caused by fungal infections, with Fusarium oxysporum being one of its most dangerous pathogens. Among the plant's defense strategies, changes in the expression of genes of the shikimate/phenylpropanoid/benzoate pathway and thus in phenolic contents occur. Among the benzoates, salicylic acid, and its methylated form methyl salicylate play an important role in regulating plants' response to stress conditions. Upon treatment of flax plants with the fungus we found that methyl salicylate content increased (4.8-fold of the control) and the expression profiles of the analyzed genes suggest that it is produced most likely from cinnamic acid, through the β-oxidative route. At the same time activation of some genes involved in lignin and flavonoid biosynthesis was observed. We suggest that increased methyl salicylate biosynthesis during flax response to F. oxysporum infection may be associated with phenylpropanoid pathway activation.

Natural phenolics greatly increase flax (Linum usitatissimum) oil stability

BACKGROUND

Flaxseed oil is characterized by high content of essential polyunsaturated fatty acids (PUFA) promoted as a human dietary supplement protecting against atherosclerosis. The disadvantage of the high PUFA content in flax oil is high susceptibility to oxidation, which can result in carcinogenic compound formation. Linola flax cultivar is characterized by high linoleic acid content in comparison to traditional flax cultivars rich in linolenic acid. The changes in fatty acid proportions increase oxidative stability of Linola oil and broaden its use as an edible oil for cooking. However one of investigated transgenic lines has high ALA content making it suitable as omega-3 source. Protection of PUFA oxidation is a critical factor in oil quality. The aim of this study was to investigate the impact of phenylpropanoid contents on the oil properties important during the whole technological process from seed storage to grinding and oil pressing, which may influence health benefits as well as shelf-life, and to establish guidelines for the selection of new cultivars.

METHODS

The composition of oils was determined by chromatographic (GS-FID and LC-PDA-MS) methods. Antioxidant properties of secondary metabolites were analyzed by DPPH method. The stability of oils was investigated: a) during regular storage by measuring acid value peroxide value p-anisidine value malondialdehyde, conjugated dienes and trienes; b) by using accelerated rancidity tests by TBARS reaction; c) by thermoanalytical - differential scanning calorimetry (DSC).

RESULTS

In one approach, in order to increase oil stability, exogenous substances added are mainly lipid soluble antioxidants from the isoprenoid pathway, such as tocopherol and carotene. The other approach is based on transgenic plant generation that accumulates water soluble compounds. Increased accumulation of phenolic compounds in flax seeds was achieved by three different strategies that modify genes coding for enzymes from the phenylpropanoid pathway. The three types of transgenic flax had different phenylpropanoid profiles detected in oil, highly increasing its stability.

CONCLUSIONS

We found that hydrophilic phenylpropanoids more than lipophilic isoprenoid compounds determine oil stability however they can work synergistically. Among phenolics the caffeic acid was most effective in increasing oil stability.

Effect of Dose and Administration Period of Seed Cake of Genetically Modified and Non-Modified Flax on Selected Antioxidative Activities in Rats

Flaxseed cake containing antioxidants is a valuable dietary component. Its nutritional effect may be diminished by the presence of anti-nutrients. The work was aimed at determining the effect of different contents of flaxseed cake in diets and their administration period on the development of rats and selected parameters of their health status. Diets with 15% and 30% addition of genetically modified (GM) flax seed cake with enhanced synthesis of polyphenols, as well as Linola non-GM flax were administered in short-term (33 days) and long-term (90 days) experiments. The 30% addition of flaxseed cake reduced digestibility of dietary nutrients, GM flaxseed cake lowered body weight gains. The relative weight of selected organs, hematological blood markers and serum activities of aspartate and alanine aminotransferases (AST, ALT) were not affected. Flaxseed cake consumption reduced serum concentration of albumins and increased globulins. Administration of 30% flaxseed cake improved plasma total antioxidant status and 30% GM flaxseed cake lowered liver thiobarbituric acid reactive substances. The activities of superoxide dismutase in erythrocytes, glutathione peroxidase in plasma and the liver concentration of 8-oxo-2′-deoxyguanosine were not changed. Most morphometric parameters of the small intestine did not differ between feeding groups. The administration of diets with 30% addition of flaxseed cake for 90 days improved the antioxidant status in rats.

Polyamine metabolism in flax in response to treatment with pathogenic and non-pathogenic Fusarium strains

Flax crop yield is limited by various environmental stress factors, but the largest crop losses worldwide are caused by Fusarium infection. Polyamines are one of the many plant metabolites possibly involved in the plant response to infection. However, in flax plants the polyamine composition, genes involved in polyamine synthesis, and in particular their regulation, were previously unknown. The aim of this study was to investigate the polyamine synthesis pathway in flax and its involvement in response to pathogen infection. It is well established that polyamines are essential for the growth and development of both plants and fungi, but their role in pathogen infection still remains unknown. In our study we correlated the expression of genes involved in polyamine metabolism with the polyamine levels in plant tissues and compared the results for flax seedlings treated with two pathogenic and one non-pathogenic strains of Fusarium. We observed an increase in the expression of genes participating in polyamine synthesis after fungal infection, and it was reflected in an increase of polyamine content in the plant tissues. The highest level of mRNA was characteristic for ornithine decarboxylase during infection with all tested, pathogenic and non-pathogenic, Fusarium strains and the arginine decarboxylase gene during infection with the pathogenic strain of Fusarium culmorum. The main polyamine identified in the flax seedlings was putrescine, and its level changed the most during infection. Moreover, the considerable increase in the contents of cell wall-bound polyamines compared to the levels of free and conjugated polyamines may indicate that their main role during pathogen infection lies in strengthening of the cell wall. In vitro experiments showed that the polyamines inhibit Fusarium growth, which suggests that they play an important role in plant defense mechanisms. Furthermore, changes in metabolism and content of polyamines indicate different defense mechanisms activated in flax in response to infection by pathogenic and non-pathogenic Fusarium strains.

[The development, differentiation and composition of flax fiber cells]

Having vascular origin, flax fiber belongs to the sclerenchyma (steroids) and its structure is limited to the cell wall. What determines fiber properties is its composition, which in practice means the composition of the secondary cell wall. It consists of four main polymers which constitute approximately 90% of the fiber: cellulose, hemicellulose, pectin, lignin, and a variety of secondary metabolites, proteins, waxes and inorganic compounds. The cell wall is a structure with a high complexity of both the composition and interactions of the particular elements between themselves. It is determined by differentiation and cell growth as well as environmental factors, biotic and abiotic stresses. The molecular background of these processes and mechanisms regulating the synthesis and rearrangement of secondary cell walls components are being intensively studied. In this work we described the latest news about the development, composition and metabolism of flax fiber cell wall components together with the molecular explanation of these processes.

Oligonucleotide treatment causes flax β-glucanase up-regulation via changes in gene-body methylation

BACKGROUND

Nowadays, the challenge for biotechnology is to develop tools for agriculture and industry to provide plants characterized by productivity and quality that will satisfy the growing demand for different kinds of natural products. To meet the challenge, the generation and application of genetically modified plants is justified. However, the strong social resistance to genetically modified organisms and restrictive regulations in European Union countries necessitated the development of a new technology for new plant types generation which uses the knowledge resulting from analysis of genetically modified plants to generate favourably altered plants while omitting the introduction of heterologous genes to their genome. Four-year experiments led to the development of a technology inducing heritable epigenetic gene activation without transgenesis.

RESULTS

The method comprises the induction of changes in methylation/demethylation of the endogenous gene by the plant's treatment with short oligodeoxynucleotides antisense to the coding region. In vitro cultured plants and F3 generation flax plants overproducing the β-1,3-glucanase gene (EMO-βGlu flax) were characterized by up-regulation of β-glucanase and chitinase genes, decreases in the methylation of CCGG sequences in the β-glucanase gene and in total DNA methylation and, more importantly, reasonable resistance against Fusarium infection. In addition, EMO-βGlu flax obtained by this technology showed similar features as those obtained by genetic engineering.

CONCLUSION

To our best knowledge, this is the first report on plant gene activation by treatment with oligodeoxynucleotides homologous to the coding region of the gene. Apart from the evident effectiveness, the most important issue is that the EMO method allows generation of favourably altered plants, whose cultivation makes the plant producer independent from the complicated procedure of obtaining an agreement on GMO release into the environment and whose products might be more easily introduced to the global market.

Genetically modified flax expressing NAP-SsGT1 transgene: examination of anti-inflammatory action

The aim of the work was to define the influence of dietary supplementation with GM (genetically modified) GT#4 flaxseed cake enriched in polyphenols on inflammation development in mice liver. Mice were given ad libitum isoprotein diets: (1) standard diet; (2) high-fat diet rich in lard, high-fat diet enriched with 30% of (3) isogenic flax Linola seed cake; and (4) GM GT#4 flaxseed cake; for 96 days. Administration of transgenic and isogenic seed cake lowered body weight gain, of transgenic to the standard diet level. Serum total antioxidant status was statistically significantly improved in GT#4 flaxseed cake group and did not differ from Linola. Serum thiobarbituric acid reactive substances, lipid profile and the liver concentration of pro-inflammatory cytokine tumor necrosis factor-α were ameliorated by GM and isogenic flaxseed cake consumption. The level of pro-inflammatory cytokine interferon-γ did not differ between mice obtaining GM GT#4 and non-GM flaxseed cakes. The C-reactive protein concentration was reduced in animals fed GT#4 flaxseed cake and did not differ from those fed non-GM flaxseed cake-based diet. Similarly, the liver structure of mice consuming diets enriched in flaxseed cake was improved. Dietetic enrichment with GM GT#4 and non-GM flaxseed cakes may be a promising solution for health problems resulting from improper diet.

Bactericidal activities of GM flax seedcake extract on pathogenic bacteria clinical strains

BACKGROUND

The antibiotic resistance of pathogenic microorganisms is a worldwide problem. Each year several million people across the world acquire infections with bacteria that are antibiotic-resistant, which is costly in terms of human health. New antibiotics are extremely needed to overcome the current resistance problem.

RESULTS

Transgenic flax plants overproducing compounds from phenylpropanoid pathway accumulate phenolic derivatives of potential antioxidative, and thus, antimicrobial activity. Alkali hydrolyzed seedcake extract containing coumaric acid, ferulic acid, caffeic acid, and lignan in high quantities was used as an assayed against pathogenic bacteria (commonly used model organisms and clinical strains). It was shown that the extract components had antibacterial activity, which might be useful as a prophylactic against bacterial infection. Bacteria topoisomerase II (gyrase) inhibition and genomic DNA disintegration are suggested to be the main reason for rendering antibacterial action.

CONCLUSIONS

The data obtained strongly suggest that the seedcake extract preparation is a suitable candidate for antimicrobial action with a broad spectrum and partial selectivity. Such preparation can be applied in cases where there is a risk of multibacterial infection and excellent answer on global increase in multidrug resistance in pathogenic bacteria.

Manipulating cinnamyl alcohol dehydrogenase (CAD) expression in flax affects fibre composition and properties

BACKGROUND

In recent decades cultivation of flax and its application have dramatically decreased. One of the reasons for this is unpredictable quality and properties of flax fibre, because they depend on environmental factors, retting duration and growing conditions. These factors have contribution to the fibre composition, which consists of cellulose, hemicelluloses, lignin and pectin. By far, it is largely established that in flax, lignin reduces an accessibility of enzymes either to pectin, hemicelluloses or cellulose (during retting or in biofuel synthesis and paper production).Therefore, in this study we evaluated composition and properties of flax fibre from plants with silenced CAD (cinnamyl alcohol dehydrogenase) gene, which is key in the lignin biosynthesis. There is evidence that CAD is a useful tool to improve lignin digestibility and/or to lower the lignin levels in plants.

RESULTS

Two studied lines responded differentially to the introduced modification due to the efficiency of the CAD silencing. Phylogenetic analysis revealed that flax CAD belongs to the "bona-fide" CAD family. CAD down-regulation had an effect in the reduced lignin amount in the flax fibre cell wall and as FT-IR results suggests, disturbed lignin composition and structure. Moreover introduced modification activated a compensatory mechanism which was manifested in the accumulation of cellulose and/or pectin. These changes had putative correlation with observed improved fiber's tensile strength. Moreover, CAD down-regulation did not disturb at all or has only slight effect on flax plants' development in vivo, however, the resistance against flax major pathogen Fusarium oxysporum decreased slightly. The modification positively affected fibre possessing; it resulted in more uniform retting.

CONCLUSION

The major finding of our paper is that the modification targeted directly to block lignin synthesis caused not only reduced lignin level in fibre, but also affected amount and organization of cellulose and pectin. However, to conclude that all observed changes are trustworthy and correlated exclusively to CAD repression, further analysis of the modified plants genome is necessary. Secondly, this is one of the first studies on the crop from the low-lignin plants from the field trail which demonstrates that such plants could be successfully cultivated in a field.

Indices of insulin resistance and dyslipidemia are correlated with lymphocyte proneness to apoptosis in obese or overweight low birth weight children

AIMS

Our aim was to study the relationship between markers of cell proneness to apoptosis and indices of insulin resistance and dyslipidemia in children born with low birth weight (LBW).

METHODS

The study comprised 177 prepubertal children stratified by birth weight and their nutritional status into LBW (n = 138) and normal birth weight (NBW; n = 39) groups. We analyzed DNA from peripheral blood lymphocytes, separated by pulsed-field gel electrophoresis (PFGE), as well as the serum levels of cholesterol, HDL-cholesterol, triglycerides, fasting insulin and glucose, caspase 3, and BCL2.

RESULTS

LBW children with a BMI SDS >1.55 demonstrated increased content of the large fragments of the lymphocyte DNA [300-500 kb (DNA300-500 kb)] in electrophoretic slides (a marker of decreased chromatin stability and susceptibility of cells to apoptosis) compared to the NBW group. In these children the level of DNA300-500 kb exhibited a strong negative correlation with the serum level of antiapoptotic protein of BCL2 (r = -0.901). DNA300-500 kb significantly correlated with calculated indices of insulin resistance: HOMA-IR and QUICKI as well as with the indices of lipid homeostasis (Castelli and AIP).

CONCLUSIONS

Increased susceptibility of lymphocytes to apoptosis correlated with a higher risk of insulin resistance and lipid disturbance in overweight or obese LBW children. A comprehensive study of the proneness of cells to apoptosis should be implemented to further investigate the pathomechanism of the metabolic syndrome in these children.

Crossbreeding of transgenic flax plants overproducing flavonoids and glucosyltransferase results in progeny with improved antifungal and antioxidative properties

Flavonoids are a large group of secondary plant metabolites with many important functions; they play a role in fruit, flower and seed pigmentation and are involved in multiple protective mechanisms. They are very active natural antioxidants, acting as antimicrobial compounds in defense against pathogens, and they protect the plant against various stress factors, including excessive solar radiation and temperature. They are also an animal deterrent. Flax is already a very useful crop plant with nutritional and biomedical applications. With increased phenylpropanoid content, flax plants could be used in the production of improved dietary supplements and antimicrobial agents. The main aim of this study was to engineer a flax variety with increased flavonoid content by crossing two transgenic flax varieties that have heightened flavonoid levels. A mother plant that over expresses genes encoding the flavonoid biosynthesis pathway enzymes chalcone synthase, chalcone isomerase and dihydroflavonol reductase was crossed with plants overexpressing the glucosyltransferase (GT) gene. It was expected that the progeny would display better properties thanks to the simultaneous increases in flavonoid synthesis and stability. In comparison to the control and parental plants, plants of the selected flax lines were found to have increased contents of flavonoids and other phenylpropanoids, including phenolic acids, in their stems and seeds. A significant increase in the secoisolariciresinol diglucoside content was found in the seeds. The antioxidative properties of extracts from W92 × GT crossbreed plants were higher than the control (non-transgenic) and parental plants. These results correlated with the increase in the susceptibility of the crossbreeds to Fusarium infection. The increased flavonoid content did not cause any negative phenotypic changes or reduce the yield of seeds.

Transgenic potato plants with overexpression of dihydroflavonol reductase can serve as efficient nutrition sources

Potato (Solanum tuberosum) is considered to be one of the most important crops cultivated in Europe and the entire world. The tubers of the potato are characterized by rich starch and protein contents and high concentrations of antioxidants, such as vitamin C and flavonoids. Notably, the presence of the phenolic antioxidants is of high importance as they have health-related properties. They are known to reduce the incidence of atherosclerosis, prevent certain kinds of cancer, and aid with many other kinds of diseases. The aim of this study was to find the most efficient way to increase the content of phenolic antioxidants in potato tubers through transgenesis. The results showed that the most efficacious way to achieve this goal was the overexpression of the dihydroflavonol reductase gene (DFR). The produced transgenic potato plants served as a nutrition source for laboratory rats; the study has confirmed their nontoxicity and nutritional benefits on the tested animals.

Flax terpenoid pathway as a source of health promoting compounds

Flax is an important crop plant grown mainly for its fiber and seeds, which are also rich in omega-3 fatty acids and valuable antioxidants derived from the terpenoid pathways including carotenoids, tocochromanols and sterols. Many of those components found in flax have been recently shown to positively influence human health. Although terpenes vary greatly in their chemical structure, mainly two mechanisms of their biological activity can be considered: direct antioxidation, and a recently explored one, connected to specific receptor and cell signaling pathway activation. Recent studies show that many of the health promoting agents derived from flax act through both of the mentioned mechanisms, resulting in synergistic physiological effects. The work summarizes the two mechanisms, focusing mainly on the one involving cell signaling, as a promising target for medicine and pharmacotherapy.

Fibres from flax overproducing β-1,3-glucanase show increased accumulation of pectin and phenolics and thus higher antioxidant capacity

BACKGROUND

Recently, in order to improve the resistance of flax plants to pathogen infection, transgenic flax that overproduces β-1,3-glucanase was created. β-1,3-glucanase is a PR protein that hydrolyses the β-glucans, which are a major component of the cell wall in many groups of fungi. For this study, we used fourth-generation field-cultivated plants of the Fusarium -resistant transgenic line B14 to evaluate how overexpression of the β-1,3-glucanase gene influences the quantity, quality and composition of flax fibres, which are the main product obtained from flax straw.

RESULTS

Overproduction of β-1,3-glucanase did not affect the quantity of the fibre obtained from the flax straw and did not significantly alter the essential mechanical characteristics of the retted fibres. However, changes in the contents of the major components of the cell wall (cellulose, hemicellulose, pectin and lignin) were revealed. Overexpression of the β-1,3-glucanase gene resulted in higher cellulose, hemicellulose and pectin contents and a lower lignin content in the fibres. Increases in the uronic acid content in particular fractions (with the exception of the 1 M KOH-soluble fraction of hemicelluloses) and changes in the sugar composition of the cell wall were detected in the fibres of the transgenic flax when compared to the contents for the control plants. The callose content was lower in the fibres of the transgenic flax. Additionally, the analysis of phenolic compound contents in five fractions of the cell wall revealed important changes, which were reflected in the antioxidant potential of these fractions.

CONCLUSION

Overexpression of the β-1,3-glucanase gene has a significant influence on the biochemical composition of flax fibres. The constitutive overproduction of β-1,3-glucanase causes a decrease in the callose content, and the resulting excess glucose serves as a substrate for the production of other polysaccharides. The monosaccharide excess redirects the phenolic compounds to bind with polysaccharides instead of to partake in lignin synthesis. The mechanical properties of the transgenic fibres are strengthened by their improved biochemical composition, and the increased antioxidant potential of the fibres supports the potential use of transgenic flax fibres for biomedical applications.

Improved properties of micronized genetically modified flax fibers

The aim of this study was to investigate the effect of micronization on the compound content, crystalline structure and physicochemical properties of fiber from genetically modified (GM) flax. The GM flax was transformed with three bacterial (Ralstonia eutropha) genes coding for enzymes of polyhydroxybutyrate (PHB) synthesis and under the control of the vascular bundle promoter. The modification resulted in fibers containing the 3-hydroxybutyrate polymer bound to cellulose via hydrogen and ester bonds and antioxidant compounds (phenolic acids, vanillin, vitexin, etc.). The fibers appeared to have a significantly decreased particle size after 20h of ball-milling treatment. Micronized fibers showed reduced phenolic contents and antioxidant capacity compared to the results for untreated fibers. An increased level of PHB was also detected. Micronization introduces structural changes in fiber constituents (cellulose, hemicellulose, pectin, lignin, PHB) and micronized fibers exhibit more functional groups (hydroxyl, carboxyl) derived from those constituents. It is thus concluded that micronization treatments improve the functional properties of the fiber components.

The response of diabetic foot to a new type of dressing

Background

FlaxAid is a newly developed type of dressing enriched in particular flavonoids through genetic engineering of flax plants that exhibit health-promoting activities due to their strong antioxidant properties. The purpose of the current study was to assess the clinical efficacy of the FlaxAid bandage therapy for a patient affected with a diabetic foot ulcer which was unresponsive to previous treatments. The patient was treated with FlaxAid bandages for 12 weeks and the size and properties of the wound were routinely observed and recorded. Due to the the clinical picture of the wound study design was adopted whereby the comparative treatment was cotton gauze wetted with isotonic salt solution.

Findings

Following therapy, the foot ulcer decreased in size, despite the decompensation of advanced diabetes. It is believed that the beneficial nature of FlaxAid is derived from its high level and broad spectrum of antioxidants.

Conclusions

The FlaxAid dressing provides a novel and effective method for the treatment of diabetic foot ulcers. This study presents a preliminary pilot investigation and a larger number of subjects need to be included within the study in order to draw firm clinical conclusions. Efforts to this effect are currently under way.