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PubMed1988

Malate dehydrogenase isozymes in flax genotroph leaves: differences in apparent molecular weight and charge between and within L and S.

Ferguson plots demonstrated that corresponding malate dehydrogenase (MDH) isozymes of Durrant's L and S flax genotrophs differ in apparent molecular weight (MW) and also in net negative charge. The MW differences explain heritable differences in electrophoretic relative mobility (Rm) between corresponding L and S isozymes. The MW for each MDH isozyme was higher for L than for S and resulted in a slower Rm for L. The net negative charge for each isozyme was higher for L than for S. MDH isozymes also differ in MW within L and S. MW was lower for isozymes in leaves from the bottom of the stem than in leaves from the top of the stem, particularly in L. Integration of information on the MDH isozyme system in the flax genotrophs and information on the peroxidase system suggests the possibility that common modifier loci may control Rm in both enzymes.

Isoenzymes↗
PubMed2004

The gene product specified by a double stranded RNA in the flax rust (Melampsora lini) is expressed during rust growth.

Strain SP6 of the flax rust (Melampsora lini) contains 11 double-stranded RNAs (dsRNAs) of unknown function. A large open-reading frame (B3ORF1 in dsRNA B3 encodes a polypeptide of 614 amino acids, and using an antiserum raised against the B3ORF1-glutathione S-transferase fusion protein prepared from a bacterial expression system, we have detected the presence of a 67 kDa polypeptide in rust urediospores. This polypeptide, identical in size to that of the predicted translation product of B3ORF1 , was not detected in spores from either a fungal strain lacking the B3 dsRNA or an isogenic strain containing no dsRNA. These data indicate that B3ORF1 present in the flax rust B3 dsRNA is expressed in vivo which warrants farther investigation in search for its function during rust development.

Basidiomycota↗
PubMed1993

Removal of fiber from vines by solid state fermentation/enzymatic degradation: a comparison of flax and kudzu retting.

Kinetic data describing the decomposition of the outer sheath of kudzu vines (undergoing a solid fermentation process in a glass beaker of soil) have been analyzed to determine the two constants, K(m)/S(o) and V/S(o), where S(o) is the initial substrate concentration, K(m) the Michaelis constant, and V the maximum product rate. The kinetic data are expressed by a simple time-varying desheathing index, obtained from the number of spatula scrapings required to reach the desired hard cellulosic fibers (vascular bundles) of the plant. A simple relationship between the desheathing index, D.I. and the dimensionless product concentration, P/S(o), is proposed to relate the D.I. data and enzyme kinetic concentration data. Thus, the Michaelis-Menten enzyme kinetic parameters can be estimated from easily obtained physical (non-chemical data; the D.I.(t) measurements). This low energy process for processing vines into valuable fibers is similar to the traditional microbial method for recovering flax fibers for linen cloth, by retting of the flax plant vines, except there is no unbound liquid water present in the soil medium.

Journal Article↗
PubMed2003

Wetting behavior of flax fibers as reinforcement for polypropylene.

The wetting behavior of several flax (cellulose as reference) and polypropylene fibers is characterized by measuring the wetting rates (penetration velocities) of a series of liquids using the capillary rise technique. This present paper aims to provide a deeper understanding of the complex nature of natural fibers and their surface properties. The fiber surface tensions are estimated from plots of the normalized wetting rate as a function of the surface tension of the liquids assuming, in analogy to Zisman's method, that the maximum of the normalized wetting rate corresponds to the solid surface tension. The estimated surface tensions of the investigated flax fibers indicate that all the fibers are quite "hydrophobic." The method used to separate the fibers from the rest of the plants has a large influence on the estimated fiber surface tensions. In the case of polypropylene (PP) fibers, the estimated surface tension corresponds well with literature data. Grafting small amounts of maleic acid anhydrite (MAH) onto the PP surfaces will not affect the wetting behavior and, therefore, the surface tension, whereas grafting larger amounts (10 wt%) of MAH causes the polymer surface tension to increase significantly. Additional pH-dependent zeta-potential measurements show that even the "pure" PP-fibers contain acidic surface functions, possibly due to further processing at elevated temperatures (thermal degradation or other aging processes).

Journal Article↗
PubMed1982

The flax industry in Northern Ireland twenty years on.

In 1961-62 a survey of respiratory symptoms in 2528 workers in flax mills in Northern Ireland and of dust levels in the mills was conducted. The workers were followed up in 1978, because recent developments suggested that an upturn in the industry was likely. Flax dust has an acute, reversible effect on the respiratory system, and byssinosis is a prescribed disease under the Industrial Injuries Act (1965). However, the follow-up study found no evidence of an effect on survival of either exposure to dust or byssinosis. The number of applications to compensation panels for assessment and certification of byssinosis has increased greatly in Northern Ireland. Although certification is independent of any subsequent common law claim by a worker for compensation on the grounds of disablement consequent on negligence by his employer, it must weight heavily in such a claim. About 50 common law claims have been settled out of court for large sums in Northern Ireland, and 950 claims are waiting to be heard. The future cost to the industry is estimated to be at least 16 million pounds. Since byssinosis appears not to cause excess mortality, it is unlikely to cause serious long-term morbidity. Although workers should be compensated for disablement due to negligence, in the absence of unequivocal evidence of disablement caused by byssinosis the financial settlements being reached in Northern Ireland seem unreasonable.

Byssinosis↗
PubMed1997

Galactans and cellulose in flax fibres: putative contributions to the tensile strength.

The proton spin-spin relaxation time, T2, measured from solid-state NMR, indicates a greater rigidity for cellulose than for the adhesive matrix between the microfibrils of flax ultimate fibres. Cytochemical and biochemical analyses allow the identification of: (1) EDTA-soluble RG I-polymers in the primary walls and cell junctions of fibres; (2) long 1 --> 4-beta-D-galactan chains between primary and secondary wall layers; and (3) arabinogalactan-proteins throughout the secondary walls. These polymers in the adhesive matrix between microfibrils and/or cellulose layers ensure that cracks propagate along the matrix rather than across the fibres and play an important role in allowing flax fibres to approach the tensile strength of advanced synthetic fibres like carbon and Kevlar.

Biopolymers↗
PubMed2001

Isolation of a flax pectin methylesterase promoter and its expression in transgenic tobacco.

Pectin methylesterases (PME) catalyze the de-esterification of methoxylated pectins in plant cell walls. We have isolated a 1.9 kb regulatory region upstream from the Lupme3 coding sequence of Linum usitatissimum L. (flax) using a 'Polymerase Chain Reaction (PCR) walking' strategy. Two 5' truncated deletion fragments (1.5 and 0.44 kb) of this potential promoter sequence were inserted upstream of the gus reporter gene in order to study their expression in transgenic plants. These constructs were transferred into Nicotiana tabacum, a heterologous system using Agrobacterium tumefaciens. Expression of the reporter gene was analyzed in regenerated transgenic plants and calli to study the promoter activities of these sequences. This expression was observed in calli with both constructs. In contrast, expression in organs was only detected in tobacco plants transformed with the largest (1.5 kb) construct. This long fragment triggered expression in roots and immature or vitrified leaves. Expression in both organs was localized in the vasculature, but also detected in the root meristem. These results are the first evidence, to our knowledge, of the spatial and temporal regulation of a specific pme promoter of flax. Localization of Lupme3 promoter activity in vascular tissues of immature organs provides an insight into the role of this PME isoform in cell elongation and differentiation.

Journal Article↗
PubMed2001

Ontogenic variations in n-alkanes during somatic embryogenesis of flax (Linum usitatissimum L.).

Hypocotyl segments (HS) of flax seedlings germinated in vitro, were used to induce indirect somatic embryogenesis on solid medium. The composition and distribution of n-alkanes in flax tissues collected at different developmental stages were studied by capillary gas chromatography (GC) and capillary gas chromatography-mass spectrometry (GC-MS). During induction and development of callus from hypocotyl tissues a decrease in the percentage of total lipids was observed. In all types of tissue sampled - HS used as primary explants, HS with differentiating calli at the cut ends (HSC), embryogenic (EC) and non-embryogenic calli (NEC) and somatic embryos (SE) - a skewed-normal distribution of n-alkanes with a low mass range (C(13)-C(21)) were found. The highest content of n-alkanes occurred in the primary hypocotyl explants and in the early stages of callus development. Longer carbon chain n-alkanes were observed only in the mature or differentiated tissues of hypocotyls and SE. Although the n-alkane contents decreased with time, in SE and calli, a significantly lower n-alkane content was observed in EC when compared to NEC independent of the time in culture. These results suggest the utilisation of n-alkanes for heterotrophic cellular growth as well as its mobilisation from EC to developing SE.

Journal Article↗
PubMed1997

Hydroxyl radical-scavenging property of secoisolariciresinol diglucoside (SDG) isolated from flax-seed.

Recently there has been a moderate resurgence in the use of flax-seed in a variety of ways including bread. The scientific basis of its use is very limited. There is some claim for beneficial effects in cancer and lupus nephritis. These claims could be due to its ability to scavenge oxygen radicals. However, its antioxidant activity is not known. Recently a method has been developed to isolate secoisolariciresinol diglucoside (SDG) from defatted flax-seed in large quantity (patent pending). We investigated the ability of SDG to scavenge .OH using high pressure liquid chromatography (HPLC) method. .OH was generated by photolysis of H2O2 (1.25-10.0 mumoles/ml) with ultraviolet light and was trapped with salicylic acid which is hydroxylated to produce .OH-adduct products 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA. H2O2 produced a concentration-dependent .OH as estimated by 2,3-DHBA and 2,5-DHBA. A standard curve was constructed for known concentrations of 2,3-DHBA and 2,5-DHBA against corresponding area under the peaks which then was used for measurement of 2,3-DHBA and 2,5-DHBA generated by UV irradiation of H2O2 in the presence of salicylic acid. SDG in the concentration range of 25, 50, 100, 250, 500, 750, 1000 and 2000 micrograms/ml (36.4, 72.8, 145.6, 364.0, 728.0, 1092.0, 1456.0 and 2912.0 microM respectively) produced a concentration-dependent decrease in the formation of 2,3-DHBA and 2,5-DHBA, the inhibition being 4 and 4.65% respectively with 25 micrograms/ml (36.4 microM) and 82 and 74% respectively with 2000 micrograms/ml (2912.0 microM). The decrease in .OH-adduct products was due to scavenging of .OH and not by scavenging of formed 2,3-DHBA and 2,5-DHBA. SDG prevented the lipid peroxidation of liver homogenate in a concentration-dependent manner in the concentration range from 319.3-2554.4 microM. These results suggest that SDG scavenges .OH and therefore has an antioxidant activity.

Butylene Glycols↗
PubMed1992

Localization of methyltransferase activities throughout the endomembrane system of flax (Linum usitatissimum L) hypocotyls.

A microsomal fraction from flax hypocotyls (Linum usitatissimum L) showed a methylation ability from S-adenosyl-methionine on to the cell wall polysaccharides. Two kinds of methylation were found: (i) a methyl esterification of uronic acids in the oxalate extracts and (ii) an O-methylation of the hydroxyl groups in the NaOH extracts. The methyltransferase study showed a rapid decrease of the methyl esterification abilities, whereas the O-methylation on to the hydroxyl groups was maintained throughout the culture duration. The localization of such activities in the flax endomembrane system was performed using isopycnic centrifugation. Enzymic marker tests allowed us to identify the different membrane types. Methyltransferase activities in the different enriched fractions appeared to be associated with the Golgi apparatus for the O-methylation, and with the plasma membrane, Golgi apparatus and endoplasmic reticulum compartments for the carboxymethyl esterification.

Acid Anhydride Hydrolases↗
PubMed1981

Organisation of the 5S RNA genes in flax.

The 5S RNA genes of flax [Linum usitatissimum] are arranged as tandem arrays of a 0.35 - 0.37kb repeating sequence. The 5S DNA is extensively methylated at CCGG and CCGG. In contrast to the rDNA, the 5S DNA sequences exhibit both length and sequence heterogeneity. The number of copies of this sequence varies between 117,000 and 49,600 per 2C nucleus in different lines of flax, and does not correlate with the number of rRNA genes.

Base Sequence↗
PubMed1996

Immobilization of flax protoplasts in agarose and alginate beads. Correlation between ionically bound cell-wall proteins and morphogenetic response.

Linum usitatissimum protoplast-derived colonies that are cultured in auxin-supplemented medium and immobilized in Ca(2+)-alginate matrix form round colonies that develop into polarized, embryo-like structures. On the other hand, protoplast-derived colonies that are immobilized in agarose do not show an organized morphogenetic response, and unique, ionically bound cell-wall protein patterns match this response. Although only slight differences in neosynthesized or total constitutive polypeptides are observed, dramatic changes in ionically bound cell-wall proteins are seen. In protoplasts grown on Ca(2+)-alginate-solidified, auxin-containing medium, several basic polypeptides were strongly induced and were found tightly bound to the cell wall. In contrast, these basic proteins were found only weakly bound to the walls of protoplasts grown on agarose-solidified, auxin-containing medium or on Ca(2+)-alginate-solidified, auxin-free medium, in which they were released into the medium. Our results suggest that plant cells can perceive and respond to the adjacent extracellular matrix, since we show that the growth of flax cells on Ca(2+)-alginate in the presence of auxin-containing medium may promote the binding of specific proteins to the walls. This establishes a direct correlation of an embryo-like morphogenesis with ionically bound cell-wall basic proteins in flax protoplasts grown on Ca(2+)-alginate-solidified, auxin-containing medium.

Alginates↗
PubMed1997

Turnover of Galactans and Other Cell Wall Polysaccharides during Development of Flax Plants.

We investigated the synthesis and turnover of cell wall polysaccharides of the flax (Linum usitatissimum L.) plant during development of the phloem fibers. One-month-old flax plants were exposed to a 40-min pulse with 14CO2 followed by 8-h, 24-h, and 1-month periods of chase with ambient CO2, and radioactivity in cell wall sugars was determined in various plant parts. The relative radioactivity of glucose in noncellulosic polysaccharides was the highest compared with all other cell wall sugars immediately after the pulse and decreased substantially during the subsequent chase. The relative radioactivities of the other cell wall sugars changed with differing rates, indicating turnover of specific polysaccharides. Notably, after 1 month of chase there was a marked decrease in the proportional mass and total radioactivity in cell wall galactose, indicating a long-term turnover of the galactans enriched in the fiber-containing tissues. The ratio of radiolabeled xylose to arabinose also increased during the chase, indicating a turnover of arabinose-containing polymers and interconversion to xylose. The pattern of label redistribution differed between organs, indicating that the cell wall turnover processes are tissue- and cell-specific.

Journal Article↗
PubMed1982

Changes in two ribonuclease isozymes during rust infection of flax cotyledons.

A ribonuclease fraction previously purified from flax by gel filtration was further resolved into two components by hydroxyl apatite chromatography. These were homogeneous with respect to electrophoresis and isoelectric focusing. Both enzymes are of RNase I type but differ in substrate specificity, kinetic properties, pH response, and isoelectric point.The two RNase isozymes show consistent properties when extracted from variety Bison (susceptible) or variety Bombay (resistant) with or without infection with race 3 of flax rust. The relative amounts of these isozymes change markedly during infection. These observations provide an explanation for the apparent qualitative changes in RNase noted previously. Differences between susceptible and resistant reactions in the early stages of disease are discussed.

Journal Article↗
PubMed1988

Elimination of Differences in the Mobility of Flax Isoperoxidases on PAGE by Digestion with alpha-Mannosidase.

In the flax (Linum usitatissimum) genotype Stormont cirrus, anodic peroxidases from the genotroph S migrate more slowly on PAGE and SDS-PAGE than the corresponding peroxidases from the genotroph L. When purified isoperoxidases S2 and L2 were digested with alpha-mannosidase, the difference in mobility was eliminated. Treatment with alpha-fucosidase and beta-xylosidase also altered the mobility of S2 and L2, but affected the sensitivity to the action of endo-beta-N-acetylglucosaminidase H of only S2. Our results suggest differences in posttranslational processing of the carbohydrate moiety between S and L isoperoxidases. These differences were also found in other S and L glycoenzymes (anodic acid phosphatases) as well as in the peroxidases of other flax genotypes.

Journal Article↗
PubMed1967

Importance of galacturonic Acid in controlling the retting of flax.

The empirical test was compared with the determination of pH, total acidity, and galacturonic acid (GA) as methods for establishing the termination time of the retting process in flax. The GA dosage was the best method for determining the end point of this process by distinctly dividing the phases of retting and over-retting in the bacterial loosening of flax fiber. This end point is critical in the production of standard fibers for the weaving industry.

Journal Article↗
PubMed1975

Epidemiological investigation of the role of family susceptibility and occupational and family histories in the development of byssinosis among workers exposed to flax dust.

Epidemiological investigation of 475 workers exposed to dust in flax processing has shown that family susceptibility has a decisive role in the development of byssinosis in those workers. Workers whose fathers had occupational history of exposure to flax dust were more resistant to the development of the disease than those whose fathers had no such history. Such tolerance was much higher in workers whose fathers were byssinotic than those with byssinosis-free fathers. Further hereditary and immunological investigations are, however, needed.

Adolescent↗
PubMed1984

Role of histamine in the aetiology of byssinosis. I Blood histamine concentrations in workers exposed to cotton and flax dusts.

The formation or the accumulation, or both, of histamine in the lungs may be potentiated by agent(s) present in cotton dust at higher level(s) than in flax dust and negligible in cottonseed dust. It has been suggested that such potentiation may be due to the activation of the ability of the lung to produce histamine and/or produce or recruit mast cells; this may present an acceptable explanation of the mechanism by which the propagation of the chronic effect of the dust proceeds in cotton and flax workers. Histamine accumulated in the lung over the weekend is released on exposure to dust causing the symptoms of byssinosis. The difference in the rate of histamine metabolism relative to the rate of histamine formation in byssinotic subjects leads to a more prolonged histamine accumulation than in symptom free subjects, with the consequent appearance of the symptoms of byssinosis. Continuous exposure to dust, without weekend interruption, leads to equivalent rates of histamine formation and metabolism with non-considerable histamine accumulation in the lungs and consequent absence of the symptoms of byssinosis.

Bronchitis↗