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PubMed1988

Microgravity effects on plant growth and lignification.

Lignin is a major cellular component of higher plants. One function of lignin is to support vertical plant growth in a gravity environment. Various investigators working in the 1 g environment have concluded that lignification is influenced by gravity. An experiment was designed for flight on Spacelab II to determine the effect of microgravity on lignification in young plant seedlings. A secondary objective of the experiment was to examine the effect of microgravity on overall seedling growth. Mung bean and oat seeds germinated and the seedlings grew under the Spacelab II mission. Growth of flight mung bean and oat seedlings, however, was slower, and the seedlings exhibited stem and root orientation difficulties. Flight pine seedlings were similar in appearance and growth to 1 g controls. The rate of lignin formation in seedlings grown in space was significantly less in all three species in comparison to 1 g controls. The experiment provided direct evidence that lignification is slowed in a microgravity environment.

Avena↗
PubMed2001

Enabling technologies for manipulating multiple genes on complex pathways.

Many complex biochemical pathways in plants have now been manipulated genetically, usually by suppression or over-expression of single genes. Further exploitation of the potential for plant genetic manipulation, both as a research tool and as a vehicle for plant biotechnology, will require the co-ordinate manipulation of multiple genes on a pathway. This goal is currently very difficult to achieve. A number of approaches have been taken to combine or 'pyramid' transgenes in one plant and have met with varying degrees of success. These approaches include sexual crossing, re-transformation, co-transformation and the use of linked transgenes. Novel, alternative 'enabling' technologies are also being developed that aim to use single transgenes to manipulate the expression of multiple genes. A chimeric transgene with linked partial gene sequences placed under the control of a single promoter can be used to co-ordinately suppress numerous plant endogenous genes. Constructs modelled on viral polyproteins can be used to simultaneously introduce multiple protein-coding genes into plant cells. In the course of our work on the lignin biosynthetic pathway, we have tested both conventional and novel methods for achieving co-ordinate suppression or over-expression of up to three plant lignin genes. In this article we review the literature concerning the manipulation of multiple genes in plants. We also report on our own experiences and results using different methods to perform directed manipulation of lignin biosynthesis in tobacco.

Amino Acid Sequence↗
PubMed2001

[Studies on lignocellulolytic enzymes production and biomass degradation of Pleurotus sp2 and Trametes gallica in wheat straw cultures].

Pleurotus sp2 and Trametes gallica were selected in this assay because of their high activities of lignocellulolytic enzymes and the enzyme peaks appeared at the early stage of liquid state fermentation. Solid state fermentation was also investigated for their abilities and behaviors of enzyme-production. The capabilities and characteristics of the two strains in degrading biomass were studied. When Pleurotus sp2 was incubated in wheat straw powder containing the liquid medium of low-nitrogen, no-carbon and high inorganic salt, the activities of MnP and Lac reached the peaks on the tenth day, but the activities of hemicellulases reached the peak on the 40th day. Pleurotus sp2 caused 17.6% of biomass loss. When T. gallica was incubated in wheat straw powder containing the liquid medium of hlig-nitrogen, or low-nitrogen, no-carbon and high inorganic salt, the activities of MnP reached the peaks on the tenth day, the lac and hemicelluloses on the 40th day, and the lignin peroxidases reached the peaks on the 50th day, and it caused more than 64% of biomass loss. Among them the hemicellulose was degraded by 71.96%, and the cellulose 66.21%. T. gallica was very capable of degrading lignin of wheat straw and caused 34.37% loss during 20 days, 46. 71% loss during 30 days and 70.14% loss during 60 days. It was interesting that T. gallica degraded lignin preferentially with respect to cellulose, which was very beneficial to biopulping of paper industry.

Basidiomycota↗
PubMedDate not supplied

[Antioxidant activity in fungi degrading lignocellulose substrates].

Considerable differences in lignin degradation by fungi of two ecological groups have been revealed. Xylotrophs cause a twofold decrease in the molecular weight of lignin. The degrading activity of saprotrophs is insignificant. Xylotrophs demethoxylate and oxidize lignin more rapidly than saprotrophs, showing a higher level of antioxidant activity. As follows from the comparison of the degrading and antioxidative effects, measurement of the antioxidant activity can be used in screening of fungi for the ability to degrade lignocellulose substrates.

Basidiomycota↗
PubMed2002

Infra-red spectroscopic analyses of banana waste degraded by oyster mushroom.

Carbon, hydrogen and nitrogen analyses of banana leaf and pseudostem biomass revealed their potentiality as substrates for microorganisms. Infra-red (IR) spectra of both biomass show presence of cellulose, xylan and lignin. IR spectra of leaf and pseudostem biomass degraded in solid state fermentation (SSF) by two Pleurotus species (P. sajor-caju and P. ostreatus) for 40 days showed the utilization of cellulose, xylan and lignin by these microbes. Dynamics of various lignocellulolytic enzymes of Pleurotus species and analyses of carbon, hydrogen and nitrogen contents of degraded biomass supported the same. Both the Pleurotus species exhibited lignin consumption ability on both the substrates.

Basidiomycota↗
PubMedDate not supplied

[Fungal decomposition of oat straw during liquid and solid state fermentation].

White rot fungi (Coriolus hirsutus, Coriolus zonatus, and Cerrena maxima from the collection of the Komarov Botanical Institute of the Russian Academy of Sciences) and filamentous fungi (Mycelia sterilia INBI 2-26 and Trichoderma reesei 6/16) were grown on oat straw-based liquid and solid media, as well as in a bench-scale reactor, either individually or as co-cultures. All fungi grew well on solid agar medium supplemented with powdered oat straw as the sole carbon source. Under these conditions, the mould Trichoderma reesei fully suppressed the growth of all basidiomycetes studied; conversely, Mycelia sterilia neither affected the development of any of the cultures, nor did it show any substantial susceptibility to suppression by their presence. Pure solid cultures of basidiomycetes, as well as the co-culture of Coriolus hirsutus and Cerrena maxima caused a notable bleaching of the oat straw during its consumption. When grown on the surface of oat straw-based liquid medium, the basidiomycetes consumed up to 40% polysaccharides without measurable lignin degradation (a concomitant process). Under these conditions, Mycelia sterilia decomposed no more than 25% lignin in 60 days, but this was observed only after polysaccharide exhaustion and biomass accumulation. In contrast, during solid state straw fermentation, white rot fungi consumed up to 75% cellulose and 55% lignin in 83 days (C. zonarus), whereas the corresponding consumption levels for co-cultures of Mycelia sterilia and Trichoderma reesei equaled 70 and 45%, respectively (total loss of dry weight ranged from 55 to 60%). Carbon dioxide-monitored solid-state fermentation of oat straw by the co-culture of filamentous fungi was successfully performed in an aerated bench-scale reactor.

Antibiosis↗
PubMed1992

Degradation of indulin by Candida albicans.

Candida albicans utilized 14C (ring) labelled dehydropolymer of coniferyl alcohol, 14C-teakwood lignin and indulin and released p-hydroxybenzoic acid, vanillic acid, 3,4-dihydroxybenzoic acid and catechol as by products from lignin. Candida albicans produced catechol 1,2-dioxygenase, protocatechuate 3,4-dioxygenase, intra- and extracellular polyphenol oxidase and peroxidase during indulin degradation. The study suggests that Candida albicans degrades different types of lignin.

Candida albicans↗
PubMed1986

[Effect of the inoculation of the comestible fungus Pleurotus ostreatus on the chemical composition and digestibility of barley straw].

The purpose of the present study was to determine whether incubation of the edible mushroom Pleurotus ostreatus in barley straw for 45 or 60 days, proved to be a means of increasing the nutritive value and digestibility of the straw for ruminant animals. In this respect, the following determinations were performed in untreated barley straw (control), and in incubated barley straw with the mushroom strain mentioned previously, for 45 or 60 days: pH, moisture, crude protein, ash, hemicellulose, cellulose, lignin, gross energy and in vitro digestibility of the dry matter. Results showed that crude protein percentage remained constant (p less than or equal to 0.05) in all treatments (means 2.67%), increasing the ash content of the straw incubated for 60 days. The hemicellulose and cellulose percentages diminished significantly (p less than or equal to 0.05) in the straw incubated for 45 or 60 days (16.74, 32.24, 17.43, 32.41% respectively) than in the control straw (24.54, 40.15%). The lignin percentages increased, although not significantly in the straw incubated for 45 or 60 days with respect to the control straw (8.36; 9.10, 9.06%, respectively). Energy values were lower for the straw incubated 45 or 60 days (2.70; 2.74 Kcal/g) than for the control straw (2.80 Kcal/g), without difference in the in vitro dry matter digestibility by incubating the straw for 45 or 60 days with Pleurotus ostreatus and the control (56.04; 52.65; 53.06% respectively). It is concluded that the Pleurotus ostreatus strain used in this study was unable to delignify the straw, because of its lack of fenoloxidases, enzymes which are necessary for lignin biodegradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMedDate not supplied

Degradation of lignocellulosic material and humus formation by fungi.

Cellulase activity and degradation of cellulose and lignin in wheat straw and formation of humus during degradation by Aspergillus sp., Chaetomium globosum, Fusarium solani, Paecilomyces varioti, Penicillium chrysogenum and Trichoderma viride QM9414 were studied. C. globosum, F. solani, P. varioti and P. chrysogenum produced little or no cellulase when grown on cellulose powder. However, all produced cellulase (filter paper degrading activity) when grown on wheat straw. All the cultures degraded cellulose and lignin to some extent, but P. varioti was the most efficient in cellulose and lignin degradation. There was an increase in humus-like substances after inoculation with fungi.

Cellulase↗
PubMedDate not supplied

Enzymatic/chemical analysis of dietary fiber.

The Uppsala methodology for rapid analysis and characterization of total dietary fiber, defined as the sum of dietary fiber polysaccharides (DFP) and Klason lignin, was studied. A sugar- and starch-free residue was prepared by treatment with a thermostable amylase and amyloglucosidase. Neutral DFP residues were quantified by gas chromatography as alditol acetates after acid hydrolysis of this residue, and the acid-insoluble fraction, Klason lignin, was determined gravimetrically. Uronic acid residues were quantified by decarboxylation of the original sample. The efficacy of the Uppsala methodology was tested with foods varying in fiber content and composition, including heat-treated samples. The present method allowed the analysis of up to 40 samples per week. It had good repeatability and coefficients of variation of 3-5% for the main fiber components. Fiber contents determined with the method were higher than those determined with a similar method that excludes Klason lignin and starch resistant to amylases but soluble in dimethyl sulfoxide and lower than those determined with an enzymatic/gravimetric method. Important aspects of fiber analysis, like enzyme purity and the recovery of soluble fiber on ethanol precipitation, also were investigated.

Acetylation↗
PubMedDate not supplied

Hypochlorite scavenging activity of polyphenols.

Chemiluminescence, generated by the mixture of sodium hypochlorite solution and luminol, was completely eliminated by polyphenols, such as natural lignins, phenylpropenoid monomers and polymers, and epigallocatechin gallate. On the other hand, hypochlorite scavenging activity of polysaccharides, such as PSK (Krestin) and Schizophyllan, was relatively weak. Human myelogenous leukemic cell lines (HL-60, ML-1) showed higher production of active oxygen(s) (detected by luminol chemiluminescence) and iodination capacity, than six other cultured cell lines. Since lignin did not completely eliminate the active oxygen production by HL-60 cells, possible stimulation of hypochlorite production by lignin was suggested.

Antineoplastic Agents↗
PubMed1999

Molecular insight into soil carbon turnover.

Curie-point pyrolysis-gas chromatography coupled on-line to mass spectrometry (Py-GC/MS) and isotope ratio mass spectrometry (Py-GC/IRMS) were used to determine the individual turnover rate of specific carbohydrates, lignin, lipids and N-containing compounds from French arable soils. The analysed soils were cultivated, either continuously with a C3 plant (wheat delta(13)C-value = -25.2 per thousand), or transferred to a C4 plant (maize delta(13)C-value = -11.4 per thousand) cropping 23 years ago. Most pyrolysis products identified were related to carbohydrates (furans), lipids (hydrocarbons and derivatives of benzene), proteins (nitriles and pyrrole) and lignins (phenols). The relative yield of all individual pyrolysis products was similar in the samples from the maize and control wheat soil. The isotopic enrichment between identical pyrolysis products from the two soils varied from 1 to 12 delta (delta) units, indicating that after 23 years of cultivation 7 to 90% of their C was derived from maize. This suggests a slow mean turnover time varying from 9 to 220 years. Based on the differences in isotopic enrichment of chemical structures after vegetation change the pyrolysis products could be divided into three groups: (i) pyrolysis products with a nearly complete C4 signal, e. g. phenol, derived from lignin degradation products, (ii) pyrolysis products with an intermediate isotopic enrichment of 6-8 per thousand, most likely to be a composite of remaining (possibly physically protected) fragments derived from both maize and native wheat, and (iii) pyrolysis products showing only low enrichments in (13)C of 1-3 per thousand. Most of their precursors were found to be proteinaceaous materials. This indicates that proteins or peptides are indeed preserved during decomposition and humification processes occurring in the soil. Our study highlights the potential of Py-GC/MS-C-IRMS to further novel insights into the dynamics of soil organic constituents. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2006

Bioconversion of hybrid poplar to ethanol and co-products using an organosolv fractionation process: optimization of process yields.

An organosolv process involving extraction with hot aqueous ethanol has been evaluated for bioconversion of hybrid poplar to ethanol. The process resulted in fractionation of poplar chips into a cellulose-rich solids fraction, an ethanol organosolv lignin (EOL) fraction, and a water-soluble fraction containing hemicellulosic sugars, sugar breakdown products, degraded lignin, and other components. The influence of four independent process variables (temperature, time, catalyst dose, and ethanol concentration) on product yields was analyzed over a broad range using a small composite design and response surface methodology. Center point conditions for the composite design (180 degrees C, 60 min, 1.25% H(2)SO(4), and 60% ethanol), yielded a solids fraction containing approximately 88% of the cellulose present in the untreated poplar. Approximately 82% of the total cellulose in the untreated poplar was recovered as monomeric glucose after hydrolysis of the solids fraction for 24 h using a low enzyme loading (20 filter paper units of cellulase/g cellulose); approximately 85% was recovered after 48 h hydrolysis. Total recovery of xylose (soluble and insoluble) was equivalent to approximately 72% of the xylose present in untreated wood. Approximately 74% of the lignin in untreated wood was recovered as EOL. Other cooking conditions resulted in either similar or inferior product yields although the distribution of components between the various fractions differed markedly. Data analysis generated regression models that describe process responses for any combination of the four variables.

Biodegradation, Environmental↗
PubMed2000

Functional expression of an Arabidopsis cDNA clone encoding a flavonol 3'-O-methyltransferase and characterization of the gene product.

We report that the cDNA clone (Accession No. U70424), previously isolated from Arabidopsis thaliana as encoding a caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT) (1), has now been overexpressed in Escherichia coli BL21 and its recombinant protein identified as a novel flavonol 3'-OMT. It is, therefore, renamed AtOMT1. This cDNA clone has previously been identified on the basis of its 88% amino acid sequence similarity and 80% identity to the aspen bispecific lignin OMT (2), the type member of the group involved in lignin biosynthesis. Our data indicate that this novel OMT uses the flavonol quercetin as the preferred substrate, but neither of the hydroxycinnamic acids, caffeic or 5-hydroxyferulic, to any significant extent. This indicates that the high sequence similarity/identity of AtOMT1 to that of the aspen lignin OMT (2) is not sufficient to assign the function of this gene product.

Arabidopsis↗
PubMed1991

Degradation of xenobiotics by white rot fungi.

White rot fungi such as P. chrysosporium degrade the nonrepeating, nonstereoselective, insoluble polymer lignin under conditions of nutrient limitation. The attack on lignin principally involves extracellular peroxidases (ligninases) and hydrogen peroxide. Hydroxyl radicals may also make a significant contribution. The ligninolytic system lends itself to the degradation of xenobiotics, since these often have limited solubility in water and are not readily available in soil to intracellular metabolism. A nonspecific attack should proceed at a rate independent of the target's concentration and the fungal system would be expected to remediate soil contaminated with a mixture of compounds. This contrasts with the need for induction and problems with simultaneous metabolism encountered with bacterial inoculation. The P. chrysosporium system has been found active against such diverse substrates as DDT, lindane, PCBs, TNT and crystal violet, with substantial mineralization in many cases. Some like biphenyl and triphenylmethane dyes are structurally related to lignin substructures while others bear groups such as nitro (TNT) or halogen (PCP) that are absent from the natural polymer. The fate of transformed targets varies: pentachlorophenol is incorporated into soil organic matter as a result of fungal ligninase action, whereas highly lipophilic Aroclor PCBs are converted to water-soluble metabolites. Normally less toxic intermediates are generated: for example, with benzo[a]pyrene, mutagenic arene oxides do not appear in the white rot fungal system. In certain cases, purified ligninases were also active in degrading pollutants such as PCP, benzo[a]pyrene or triphenylmethane dyes. Methods of optimizing ligninase activity in fungal reactors have been described, such as the addition of surfactants and veratryl alcohol to the medium. It remains to be seen how molecular biology can provide further advances in maximizing the bioremediating activity of white rot fungi applied to contaminated soil.

Basidiomycota↗
PubMed2005

Quantitative trait loci for cell wall components in recombinant inbred lines of maize (Zea mays L.) II: leaf sheath tissue.

While maize silage is a significant feed component in animal production operations, little information is available on the genetic bases of fiber and lignin concentrations in maize, which are negatively correlated with digestibility. Fiber is composed largely of cellulose, hemicellulose and lignin, which are the primary components of plant cell walls. Variability for these traits in maize germplasm has been reported, but the sources of the variation and the relationships between these traits in different tissues are not well understood. In this study, 191 recombinant inbred lines of B73 (low-intermediate levels of cell wall components, CWCs) x De811 (high levels of CWCs) were analyzed for quantitative trait loci (QTL) associated with CWCs in the leaf sheath. Samples were harvested from plots at two locations in 1998 and one in 1999 and assayed for neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL). QTL were detected on all ten chromosomes, most in tissue specific clusters in concordance with the high genotypic correlations for CWCs within the same tissue. Adjustment of NDF for its subfraction, ADF, revealed that most of the genetic variation in NDF was probably due to variation in ADF. The low to moderate genotypic correlations for the same CWC across leaf sheath and stalk tissues indicate that some genes for CWCs may only be expressed in certain tissues. Many of the QTL herein were detected in other populations, and some are linked to candidate genes for cell wall carbohydrate biosynthesis.

Breeding↗
PubMed2006

High levels of linkage disequilibrium and associations with forage quality at a phenylalanine ammonia-lyase locus in European maize (Zea mays L.) inbreds.

Forage quality of maize is influenced by both the content and structure of lignin in the cell wall. Phenylalanine Ammonia-Lyase (PAL) catalyzes the first step in lignin biosynthesis in plants; the deamination of L-phenylalanine to cinnamic acid. Successive enzymatic steps lead to the formation of three monolignols, constituting the complex structure of lignin. We have cloned and sequenced a PAL genomic sequence from 32 maize inbred lines currently employed in forage maize breeding programs in Europe. Low nucleotide diversity and excessive linkage disequilibrium (LD) was identified at this PAL locus, possibly reflecting selective constrains resulting from PAL being the first enzyme in the monolignol, and other, pathways. While the association analysis was affected by extended LD and population structure, several individual polymorphisms were associated with neutral detergent fiber (not considering population structure) and a single polymorphism was associated with in vitro digestibility of organic matter (considering population structure).

Genetic Markers↗
PubMed2006

Near-infrared reflectance spectroscopy as a fast and non-destructive tool to predict foliar organic constituents of several woody species.

Near-infrared reflectance spectroscopy (NIRS) was used to estimate N, neutral detergent fibre (NDF), acid detergent fibre (ADF), lignin and cellulose contents in leaves of a heterogeneous group of 17 woody species from the Central Western region of the Iberian Peninsula. The sample set consisted of 182 samples of leaves of deciduous and evergreen species, showing a wide range of concentrations determined by reference methods: 6.60-35.2 g kg-1 (N), 15.5-66.0% (NDF), 10.2-57.3% (ADF), 3.45-27.4% (lignin) and 5.79-31.3% (cellulose). Reflectance spectra, obtained for samples of dried and ground leaves, were recorded as log1/R (R=reflectance) from 1,100 to 2,500 nm. NIRS calibrations were developed using multiple linear (MLR) and partial least-squares (PLSR) regressions, and tested by external validation. Spectral data were transformed to the first and second derivative (1D, 2D). The PLSR method and derivative transformations provided the best statistics and showed lower standard errors of calibration (SEC) and higher coefficients of multiple determination (R2). In the external validation the standard errors of prediction (SEP) were 0.76 g kg-1 (N), 2.11% (NDF), 1.47% (ADF), 0.85% (lignin) and 0.86% (cellulose). The results obtained show that NIRS is very effective for the estimation of these organic constituents in leaf tissue of woody species. This technique can be used in ecological or ecophysiological studies as an alternative to the more time-consuming standard methods.

Cellulose↗