Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Flax”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed2005

Moderation of morphogenetic and oxidative stress responses in flax in vitro cultures by hydroxynonenal and desferrioxamine.

Hypocotyl segments of 7-day old seedlings of flax (Linum usitatissimum L.) cultivars Atalante, Flanders, Jitka, Szegedi 30 and Super were screened for organogenesis (shoot and root induction) and embryo-like structure production. A non-destructive assay for hydroxyl radicals (*OH), utilising DMSO as a radical trap, was used to determine *OH formation during tissue culture and morphogenesis. Desferrioxamine, an inhibitor of Fenton reaction, and 4-hydroxy-2-nonenal, a cytotoxic Lipid peroxidation product, were exogenously applied to flax cultures to determine the effect of antioxidative and prooxidative status on morphogenetic responses induced through the exogenous application of plant growth regulators. Flax genotypes varied in their response to treatments after exposure to different plant hormones. Hydroxyl radical (*OH) formation correlated with morphogenetic responses and this was affected by plant hormones. Desferrioxamine and 4-hydroxy-2-nonenal also moderated morphogenetic responses and influenced hydroxyl radical formation during in vitro propagation.

Aldehydes↗
PubMed2003

Isolation and characterization of water-soluble hemicelluloses from flax shive.

Partially depolymerized, water-soluble hemicelluloses were solubilized from flax shive employing hydrothermal microwave treatment and thereafter subjected to ion-exchange chromatography, enzymatic purification and/or size-exclusion chromatography (SEC). The oligo- and polysaccharide fractions thus obtained were characterized with respect to molar mass, molar mass distribution, degree of polymerization (DP) and degree of substitution with acetyl moieties (DSAc) by employing SEC in combination with MALDI-TOF mass spectrometry. The major portion of the water-soluble flax hemicellulose consisted of an O-acetyl-4-O-methylglucuronoxylan exhibiting a DPp value (i.e., peak-average DP) of 28. When the DSAc for this O-acetyl-4-O-methylglucuronoxylan was calculated on the basis of the MALDI-MS spectra obtained without and following deacetylation, a value of 0.7 was obtained. In addition, an O-acetyl-glucomannan (DPp=9, DS=0.4) and minor quantities of small neutral O-acetyl-xylooligosaccharides were also isolated from the mixture of water-soluble hemicelluloses released from the flax shive by microwave treatment.

Acetates↗
PubMed2002

Characterization of alkali treated flax fibres by means of FT Raman spectroscopy and environmental scanning electron microscopy.

Flax fibres grown under well managed conditions were submitted to NaOH chemical treatments, so called Mercerization. The extent of the polymorphic transformation of cellulose I into cellulose II taking place within the crystalline domains of the fibre cellulose was dependent on the alkali concentration. FT Raman spectroscopy turned out to represent an ideal tool for detecting the polymorphic transformation of the cellulosic fine structure of the flax fibres in vivo. In addition to the differences of the FT Raman spectra in the frequency range below 1500 cm(-1), second derivatives of the spectra in the range of the CH stretching vibrations could also be used to distinguish the two polymorphic modifications. The intensity ratio R of the stretching modes v(s)COC and v(as)COC represents a spectral parameter characterising the molecular structure of the flax fibres. As a supplementary tool, Environmental scanning electron microscopy (ESEM) was used to visualize the microstructural fibre properties dependent on the alkali concentrations during the Mercerization.

Cellulose↗
PubMedDate not supplied

Biodegradation of chemically modified flax fibers in soil and in vitro with selected bacteria.

The extent and rate of degradation of flax (Linum usitatissimum) fibers, both in the native state and after surface chemical modification (acetylation or poly(ethylene glycol), PEG, grafting), was investigated under laboratory conditions in two different biodegrading environments. Degradation of the fibers under aerobic conditions by the action of the microorganisms present in soil is assessed with the ASTM 5988-96 method by monitoring carbon dioxide evolution. In vitro biodegradation experiments were carried out by exposing the fibers to a pure culture of Cellvibrio fibrovorans bacteria and measuring the mass loss as a function of time. Despite the complexity of the system, the results of degradation in soil were satisfactorily reproducible, although the absolute rates were found to change in different experiments using the same soil. The degradation rate of acetylated fibers in soil nearly equals that of unmodified fibers, whereas in the pure culture, acetylated fibers biodegrade slower than native fibers. The opposite happens with the PEG-grafted fibers, which degrade slower than unmodified flax in soil and at a comparable rate upon in vitro exposure to the bacterial culture. The different biodegradation kinetics observed in the two biodegrading environments were attributed to differences of biocenoses, abiotic factors, and biodegradation assessing methods. Nevertheless, the final extent of biodegradation was the same for modified and unmodified fibers both in soil and in the pure culture, showing that the surface chemical modifications applied do not significantly affect biodegradability of the flax fibers.

Biodegradation, Environmental↗
PubMed2001

Chemical composition of components comprising bast tissue in flax.

Components from the bast region of flax (Linum usitatissium) were removed by hand from seed flax and fiber flax and analyzed by gas chromatography and mass spectrometry. Stems soaked in water were separated by hand into an outer layer, which consisted of epidermis with cuticle and parenchyma cells, and fiber bundles. Each of the two fractions were evaluated for chemical markers that could be used to predict the degree of retting and possibly fiber quality. The outer layer was subsequently treated with a mixed enzyme preparation to remove the carbohydrate portion, thus providing another fraction consisting primarily of cuticle. Four main constituent groups were investigated: dihydroxy fatty acids, long-chain fatty acids and alcohols, sterols, and aromatics. Long-chain fatty acids and alcohols located in the outer layer accounted for 80-92% of the total found in both fractions. Aromatics and sterols in the outer layer accounted for 29--72 and 27--67%, respectively, of the total and do not appear to be a reliable marker for the degree of retting. The best markers for retting were the dihydroxy fatty acids, of which 98--99% were accounted for in the outer layer. The main dihydroxy fatty acids were a mixture of 8,16- and 9,16-dihydroxyhexadecanoic acids and represented 87--89% of the total dihydroxy fatty acids measured. As a constituent of cuticle, this compound may serve as an excellent marker for indicating the degree of retting as well as a possible marker for fiber quality because this compound is almost always exclusively associated with the outer layer and not the fiber.

Alcohols↗
PubMed2006

"Green" composites from renewable resources: preparation of epoxidized soybean oil and flax fiber composites.

In recent years there has been considerable interest in using natural plant fibers as reinforcements for plastics. The motivation includes cost, performance enhancement, weight reduction, and environment concerns. High performance flax fiber could potentially substitute for glass or carbon fibers as reinforcements for plastics. This study reports the "green" composites obtained from a mixture of epoxidized soybean oil and epoxy resin, 1,1,1-tris(p-hydroxyphenyl)ethane triglycidyl ether (THPE-GE), reinforced with flax fiber. The compression molding method is used for making the composites. Curing agents triethylenetetramine and diethylenetriamine provide better physical properties of the composites than Jeffamine agents D-230 and EDR-148. Both the flexural modulus and the tensile modulus of the composites increase as the amount of THPE-GE increases. The flexural modulus increased at a fiber content of <10 wt %, but there is a decrease beyond 10 wt %. The tensile modulus increases with fiber content until a maximum at 13.5 wt %, and then it decreases. The flax fiber length affected the mechanical properties of the composites: the longer the fiber length, the better are the mechanical properties observed.

Epoxy Compounds↗
PubMed2006

Optimization of extraction of phenolic compounds from flax shives by pressurized low-polarity water.

Pressurized low-polarity water (PLPW) extraction of phenolic compounds from flax shive was investigated using statistically based optimization and the "one-factor-at-a-time" method. Extraction variables examined using central composite design (CCD) included temperature, flow rate, and NaOH concentration of the extracting water. Extraction of phenolic compounds including p-hydroxybenzaldehyde, vanillic acid, syringic acid, vanillin, acetovanillone, and feruric acid was affected by temperature and NaOH concentration; and extraction of all phenolic compounds, except ferulic acid, increased with temperature and NaOH concentration of the extracting water. Flow rate had little effect on concentration of phenolic compounds at equilibrium, but the extraction rate at the early phase was higher for higher flow rates. The mechanism of PLPW extraction of flax shive phenolics was also investigated using a two-site kinetic model and a thermodynamic model. To determine the extraction mechanism, flow rate was varied from 0.3 to 4.0 mL/min while temperature and NaOH concentration were fixed at 180 degrees C and 0.47 M, respectively. The flow rate tests showed the extraction rates of total phenolic (TP) compounds increased with flow rate and can be described by a thermodynamic model. The results from the thermodynamic model demonstrated that a K(D) value of 30 agreed with the experimental data in the flow rate range of 0.3-4.0 mL/min. When the effect of the three independent variables was evaluated simultaneously using CCD, a maximum TP concentration of 5.8 g/kg of dry flax shive (DFS) was predicted from the combination of a high temperature (230.5 degrees C), a high initial concentration of NaOH (0.63 M), and a low flow rate (0.7 mL/min). Maximum TP concentration of 5.7 g/kg of DFS was obtained from extraction conditions of 180 degrees C, 0.3 or 0.5 mL/min, and 0.47 M NaOH at equilibrium. A second-order regression model generated by CCD predicted a maximum TP concentration of 5.8 g/kg of DFS under the same extraction conditions, which is well matched with the results from experimental data.

Flax↗
PubMed2001

Biosynthetic pathway to the cancer chemopreventive secoisolariciresinol diglucoside-hydroxymethyl glutaryl ester-linked lignan oligomers in flax (Linum usitatissimum) seed.

Application of stable and radioisotope precursor/tracer experiments resulted in the identification of various phenylpropanoid, monolignol, and lignan metabolites involved in the biosynthesis of the cancer chemopreventive secoisolariciresinol diglucoside (SDG; 1)-containing ester-linked "polymer(s)" in flax (Linum usitatissimum) seed. Individual analysis of size-segregated flax seed capsules at five early stages of their development provided a metabolic profile of intermediates leading to "biopolymer" biosynthesis. The use of (1)H and (13)C NMR and HRMS analyses resulted in the identification of 6a-HMG (hydroxymethyl glutaryl) SDG (17) and 6a,6a'-di-HMG SDG (18) as the two major components of the ester-linked "biopolymer(s)". Based on metabolic tracer analyses and relative radioisotopic incorporations throughout each of these five stages of seed development, a biochemical pathway is proposed from phenylalanine to SDG (1), with subsequent mono- and di-substitutions of SDG (1) with HMG CoA. These metabolites then serve as precursors for formation of the SDG-HMG ester-linked oligomers. Results from this study will facilitate future isolation and characterization of the proteins and enzymes involved in biosynthesis of the SDG-HMG ester-linked oligomers in flax seed.

Benzimidazoles↗
PubMed2000

Effect of dietary flaxseed, flax oil and n-3 fatty acid supplement on hepatic and plasma characteristics relevant to fatty liver haemorrhagic syndrome in laying hens.

1. Two experiments were carried out to investigate the effect of dietary flaxseed, flax oil and n-3 fatty acid supplementation (Dry n-3) on hepatic fat content, plasma triglycerides, hepatic haemorrhage score, egg production, food intake and body weight in an inbred line of Single Comb White Leghorns (UCD-003) predisposed to fatty liver haemorrhagic syndrome (FLHS) and normal SCWL hens. 2. Feeding diets containing 100 g/kg ground flaxseed, 40 g/kg flax oil, or 100 g/kg Dry n-3 reduced body weight and significantly reduced hepatic fat content compared to feeding the control diet with animal and vegetable oil as a fat source. 3. Hepatic malondialdehyde, an indicator of lipid peroxidation within the liver, was not significantly affected by dietary treatment. 4. Normal SCWL hens tended to have higher egg production, greater body weight, greater food intake and higher blood triglyceride concentrations than UCD-003 hens, although the strain effects were not significant. Liver weight as a percent of body weight was significantly lower in normal SCWL hens. Treatments by strain interactions were not found. 5. The result suggested that dietary flaxseed, flax oil and Dry n-3 decrease hepatic fat content and reduce body weight, 2 of the predisposing factors believed to contribute to FLHS onset. However, haemorrhages were still apparent in both strains regardless of treatment, indicating that other unknown underlying mechanisms may also be responsible for FLHS.

Animal Feed↗
PubMed2005

Mechanisms and control of rapid genomic changes in flax.

BACKGROUND AND AIMS: The nuclear DNA of certain varieties of flax (Linum usitatissimum) can vary within a single generation when the plants are grown under specific environmental conditions. This review details the genomic variations that have been identified and associated with this environmental response. CONCLUSIONS: The variation occurs across the whole spectrum of sequence repetition and has been shown to occur in the highly repeated, middle repetitive and low copy number sequences. Although the variation has been shown to be spread throughout the genome it does not occur at random, as similar molecular events have been shown to occur repeatedly. The changes in two labile regions in the nucleus, the ribosomal RNA genes and a site-specific insertion event, have been shown to occur within the period of vegetative growth and over a relatively short period of that growth. The gradual change in total nuclear DNA that has been described would then need to have arisen through an accumulation of changes occurring over the whole, or most of the, period of growth prior to flowering. The polymorphisms that result from these rapidly occurring genomic events have also been observed in many other flax and linseed varieties as well as in the wild progenitors of flax.

Cell Nucleus↗
PubMed2001

Six amino acid changes confined to the leucine-rich repeat beta-strand/beta-turn motif determine the difference between the P and P2 rust resistance specificities in flax.

At least six rust resistance specificities (P and P1 to P5) map to the complex P locus in flax. The P2 resistance gene was identified by transposon tagging and transgenic expression. P2 is a member of a small multigene family and encodes a protein with nucleotide binding site (NBS) and leucine-rich repeat (LRR) domains and an N-terminal Toll/interleukin-1 receptor (TIR) homology domain, as well as a C-terminal non-LRR (CNL) domain of approximately 150 amino acids. A related CNL domain was detected in almost half of the predicted Arabidopsis TIR-NBS-LRR sequences, including the RPS4 and RPP1 resistance proteins, and in the tobacco N protein, but not in the flax L and M proteins. Presence or absence of this domain defines two subclasses of TIR-NBS-LRR resistance genes. Truncations of the P2 CNL domain cause loss of function, and evidence for diversifying selection was detected in this domain, suggesting a possible role in specificity determination. A spontaneous rust-susceptible mutant of P2 contained a G-->E amino acid substitution in the GLPL motif, which is conserved in the NBS domains of plant resistance proteins and the animal cell death control proteins APAF-1 and CED4, providing direct evidence for the importance of this motif in resistance gene function. A P2 homologous gene isolated from a flax line expressing the P resistance specificity encodes a protein with only 10 amino acid differences from the P2 protein. Chimeric gene constructs indicate that just six of these amino acid changes, all located within the predicted beta-strand/beta-turn motif of four LRR units, are sufficient to alter P2 to the P specificity.

Alleles↗
PubMed2005

A site-specific insertion sequence in flax genotrophs induced by environment.

A single-copy 5.7 kilobase (kb) DNA fragment, termed Linum Insertion Sequence 1 (LIS-1), has been identified and characterized. This is one of the DNA changes associated with the environmentally induced heritable changes resulting in stable lines termed genotrophs in flax (Linum usitatissimum). The insertion sequence and its insertion site have been cloned from genomic libraries and sequenced. PCR products across the insertion and surrounding regions have also been cloned and sequenced. The 5.7 kb DNA fragment is inserted into a 3.7 kb EcoRI fragment in the plastic line (Pl) with the generation of a 3 base pair duplication at the insertion site, as well as additional sequence changes. The identical insertion was also found in other genotrophs and flax varieties. The intact element was not present in Pl but appeared to be generated by a reproducible series of complex rearrangements or insertion events. LIS-1 is the result of a targeted, highly specific, complex insertion event that occurs during the formation of some of the genotrophs, and occurs naturally in many flax and linseed varieties.

Chromosomes, Plant↗
PubMed2006

Fish oil in various doses or flax oil in pregnancy and timing of spontaneous delivery: a randomised controlled trial.

OBJECTIVES: To test the earlier suggested hypothesis that intake of long-chain n-3 fatty acids from fish oil may delay the timing of spontaneous delivery and to test if alpha-linolenic acid, provided as flax oil capsules, shows the same effect. DESIGN: Randomised controlled trial including women reporting low dietary fish intake. The women were allocated in the proportions of 1:1:1:1:1:1:2 into six treatment groups and a control group, respectively, from week 17-27 of gestation. The treatment groups received fish oil, in various doses, or flax oil, and the control group did not receive any treatment. SETTING: The Danish National Birth Cohort. SAMPLE: A total of 3098 women allocated into six treatment groups and one control group. METHODS: The six intervention groups were offered fish oil capsules in doses of 0.1, 0.3, 0.7, 1.4 and 2.8 g of eicosapentaenoic acid and docosahexaenoic acid per day or 2.2 g of alpha-linolenic acid (ALA) per day from week 17-27 of gestation until delivery. MAIN OUTCOME MEASURES: Timing of spontaneous delivery. RESULTS: No differences in timing of spontaneous delivery was detected in the fish oil groups or the flax oil group, compared with the control group. The difference in timing of spontaneous delivery in the group receiving the highest fish oil dose compared with the control group was 0.8 days (95% CI: -2.3 to 1.0). Only a minority of the women in the intervention groups took capsules until delivery. CONCLUSION: Possible explanations for these findings include no true effect of n-3 fatty acids on spontaneous delivery or a quick-acting effect not detectable in this trial.

Biomarkers↗
PubMed2002

Bovine milk fatty acid profiles produced by feeding diets containing solin, flax and canola.

Fatty acid profiles with emphasis on linoleic, linolenic, oleic, and conjugated linoleic acid (CLA) were compared in milk from dairy cows fed diets containing 3.25% supplemental fat and a control diet containing no supplemented fat. The fat was supplied by either whole ground solin, flax, or canola oilseed. Solin (linola) is a new cultivar of flax that contains 28% linoleic acid in the seed, Twelve multiparous Holstein cows were assigned to one of four dietary treatments. The experimental design was a 4 x 4 Latin square with each period consisting of 16 d for adjustment to the diet followed by a 5-d sampling period. Feed intake, milk yield, milk fat yield, and milk fat percentage were not affected by treatment. Adding solin, flax, or canola oilseed to lactation diets produced the highest proportions of linoleic (C18:2), linolenic (C18:3), and oleic (C18:1) acids, respectively, in the lipid fraction of the milk of the cows consuming these diets. The proportions of C6:0 to C16:1 were depressed in the milk fat of cows fed the oilseed diets, compared with the control diet. Increasing the lactation diet levels of C18:2, by using different oilseeds, increased CLA to 1.5% of milk fatty acids. The content of CLA in milk fatty acids, however, did not increase with the solin-supplemented diet compared with the canola-supplemented diet even though the C18:2 level was higher in the former diet.

Animals↗
PubMed2003

[Genome comparisons of three closely related flax species and their hybrids with chromosomal and molecular markers].

Chromosome C-banding patterns were analyzed in three closely related flax species (Linum usitatissimum L., 2n = 30; L. angustifolium Huds., 2n = 30; and L. bienne Mill., 2n = 30) and their hybrids. In each case, the karyotype included metacentrics, submetacentrics, and one or two satellite chromosomes. Chromosomes of the three flax species were similar in morphology, size (1-3 microns), and C-banding pattern and slightly differed in size of heterochromatic regions. In all accessions, a large major site of ribosomal genes was revealed by hybridization in the pericentric region of a large metacentric. A minor 45S rDNA site was observed on a small chromosome in L. usitatissimum and L. bienne and on a medium-sized chromosome in L. angustifolium. Upon silver staining, a nucleolus-organizing region (NOR) was detected on a large chromosome in all species. In L. angustifolium, an Ag-NOR band was sometimes seen on a medium-sized chromosome. In the karyotypes of interspecific hybrids, silver-stained rDNA loci were observed on satellite chromosomes of both parental species. RAPD analysis with 22 primers revealed a high similarity of the three species. The greatest difference was observed between L. angustifolium and the other two species. The RAPD patterns of L. bienne and L. usitatissimum differed in fewer fragments. A dendrogram of genetic similarity was constructed for the three flax species on the basis of their RAPD patterns. Genome analysis with chromosome and molecular markers showed that L. bienne must be considered as a subspecies of L. usitatissimum rather than a separate species. The three species were assumed to originate from a common ancestor, L. angustifolium being closest to it.

Chimera↗
PubMed1994

Revealing the mammalian lignan precursor secoisolariciresinol diglucoside in flax seed by ionspray mass spectrometry.

Ionspray mass spectrometry allowed the rapid detection and unambiguous identification of secoisolariciresinol diglucoside, an important mammalian lignan precursor occurring in flax seed. It was observed that this compound is embedded in a complex form, probably a complex glucoside of still undisclosed structure, among the polar solvent extractables of flax seed from which it could not be released as such without the intervention of alkaline methanolysis. Comparison of ionspray mass spectra of untreated and methanolysed flax-seed extracts confirmed methanolysis as the crucial step in setting up any further analytical or preparative procedure concerned with secoisolariciresinol diglucoside.

Butylene Glycols↗
PubMed1996

Filamentous microfungi in raw flax and cotton for textile industry and their ciliostatic activity on tracheal organ cultures in vitro.

In a three-year experiment we studied mycobiota of 24 samples of flax and 45 samples of cotton processed in Slovak textile factories. We isolated 12.2 x 10(6) (on average) cfu of microfungi per 1 g of flax samples and 3.3 x 10(5) (on average) cfu of micromycetes per 1 g of cotton samples. We also studied the ciliostatic activity of metabolites of isolated filamentous fungi on tracheal cultures of 1-day-old chicks in vitro. Twenty-nine percent of 116 investigated chloroform extracts of metabolites of microfungi isolated from flax samples stopped the cilia movement and 25% of 195 had ciliostatic activity during 72 h of experiment.

Animals↗
PubMed1988

Relative mobility and activity of leaf malate dehydrogenase in flax (Linum usitatissimum) genotrophs and genotypes.

Malate dehydrogenase (MDH) band relative mobility (Rm) and activity were examined in leaf extracts of Durrant's flax genotrophs, L and S, and flax genotypes, R and M. MDH activity in leaves from just below the inflorescence was higher in the two smaller, sparsely branched plant types, S and M, than in the larger, more branched plant types, L and R. The MDH electrophoretic banding pattern in flax leaf extracts consisted of three major anionic bands, MDH-1, MDH-2, and MDH-3. No Rm differences were detected between corresponding isozymes of genotypes R and M. For the genotrophs, however, all three bands of S migrated faster than the corresponding bands of L. Codominance was absent in F1 hybrids; S Rm was dominant for MDH-2 and MDH-3 and L Rm was dominant for MDH-1. The observations suggest that MDH Rm in L and S may be controlled by a modifier locus (or loci). Previous studies indicate that a modifier locus may also control heritable genotrophic differences in peroxidase (PER) and acid phosphates (AP) Rm. The three enzyme systems are compared.

Electrophoresis↗