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PubMed2001

Pectin: cell biology and prospects for functional analysis.

Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides. Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls. This review surveys what is known about the structure and function of these pectin domains. The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes. Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts. The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties. Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain. Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.

Cell Wall↗
PubMedDate not supplied

[Formation of an extracellular system of enzymes during growth of Geotrichum candidum 3C on cell walls isolated from cereal grain capsules].

The activities of extracellular systems of hemicellulases, pectinases, and cellulases was studied during a 72-h cultivation of Geotrichum candidum 3C. The culture was grown on a medium containing 3% cell walls isolated from wheat grain capsules, which served as the sole carbon source. Enzymes catalyzing the degradation of pectin substances (beet pectin, alpha-L-arabinan, and 1,4-beta-D-galactan), as well as beta-D-galactosidase and alpha-L-arabinofuranosidase involved in their hydrolysis, were formed first (4 h after the beginning of cultivation). Enzymes hydrolyzing 4-O-methyl-alpha-D-glucurono-beta-D-xylan and sodium carboxymethyl xylan were also found in the culture liquid after 4 h of fungal growth. The contents of pectin-degrading and xylanolytic enzymes reached their maximum levels after 52-56 and 72 h of growth, respectively. Cellulolytic enzymes were detected after 8-28 h of cultivation. Enzymes degrading alpha-D-galacto-beta-D-mannan were found 24 h after the beginning of growth; their content was maximum after 72 h of cultivation.

Cell Wall↗
PubMed2000

[Effect of lanthanum on growth and biochemical property of Sclerotinia sclerotiorum].

The study shows that La2O3 at a concentration of 30-450 mg.L-1 could inhibit the growth of S. sclerotiorum in both solid and liquid media and the inhibition effect was increased with its increasing concentration. The activity of pectinase produced by S. sclerotiorum in liquid medium was also increased with increasing La2O3 concentration.

Ascomycota↗
PubMedDate not supplied

[Changes in lectin activity in plants treated with resistance inducers].

We studied the changes in lectin activity in tobacco leaf disc and potato tubers treated with polysaccharides (chitosan, glucomannan, and dextran sulfate), enzymes (cellulase and pectinase), or monosaccharides (glucose and glucosamine). All studied substances changed lectin activity to a certain extent(significantly or as a trend). The number of membrane lectins in the chloroplasts (tobacco leaf discs) usually considerably decreased immediately after the treatment (1-2 days) but increased later (2-4 days). Generally, an increased lectin activity predominated in potato tubers treated with the inducers. The enzymes increased lectin activity during the whole observation period (5 days). A pronounced antiviral activity was observed in the hypersensitive tobacco-tobacco mosaic virus system only after treatment with chitosan and glucomannan.

Cellulase↗
PubMed2000

Role of cell wall-degrading enzymes in pathogenicity of Fusarium oxysporum.

Fusarium oxysporum invades its host plants through the roots and colonizes the vascular system. It produces a great variety of cell-wall degrading enzymes (CWDE), such as cellulases, xylanases, pectinases and proteases. Our group has purified and characterized an endopolygalacturonase (PG1), two exopolygalacturonases (PG2 and PG3), an endoxylanase (XYL1) and an endo pectatelyase (PL1). We have isolated the following CWDE-encoding genes: pg1, pgx4, pg5, xyl2, xyl3, prt1 and pl1. Gene expression in different culture conditions has been determined by Northern analysis. The occurrence of these genes in different formae speciales has been analyzed by Southern analysis and PCR. All these genes are expressed during different stages of the interaction with the host plant indicating a possible role in pathogenesis. At present, targeted gene disruption is being carried out, in order to determine the role of each gene in the pathogenicity process.

Journal Article↗
PubMed2005

[Isolation of egg cells and zygotes from Torenia fournieri].

Torenia fournieri is a special plant with embryo sac partly protruding through the micropyle of ovule, and its egg cell, two synergids and part of the central cell can be clearly observed using light microscope (Plate I-1, 2). The feature of embryo sac of T. fournieri makes it easy to isolate egg cell and zygote, especially for physiologically mature and vigorous egg cell to study its fertilization mechanism. Egg cells of T. fournieri were isolated from embryo sacs 2 d after anthesis using enzymatic digestion or mechanical dissection after mild osmotic shock (Plate I-3, 4). About 5% egg cells (2-3 from 50 ovules) could be mechanically dissected within 2 h. When 0.1% cellulase and 0.1% pectinase were added into the solution, about 18% egg cells (8-10 from 50 ovules) could be isolated within 2 h (Plate I-5). Although egg cells could be isolated by mechanical dissection, they can be used in in vitro fertilization to probe fertilization mechanism without deleterious effect of enzymatic action on the surface of egg cell. But it is easier to isolate egg cells by using enzymatic digestion, and more egg cells can be obtained for the research of molecular biology. Using enzymatic digestion method, the zygote of Torenia fournieri was also isolated from the pollinated ovules (Plate I-7-10). Basing on our successful isolation of mature sperm cells, the isolation of egg cells of T. fournieri will make in vitro fertilization possible for the first time in a dicot plant.

Cell Separation↗
PubMed2005

[Study on breeding of probiotic Aspergillus nigre by N+ implantation and fermentation condition of its mutant].

Using Aspergillus niger AN01 as original strain, mutated strain Aspergillus niger AN03 was obtained by N+ implantation. The results showed that activities of acidic protease, cellulase and pectinase of Aspergillus niger were raised from 71.6U/g, 141.7U/g and 264.8U/g to 996.5U/g, 940.4U/g and 906.5U/g respectively. Characteristics of enzymes production in the mutant Aspergillus niger AN03 kept stabile by 5 times subculture. In addition, the optimum conditions for enzymes production of Aspergillus niger AN03 were investigated. The optimum components of medium consisted of bran 105.0g, corn straw 105.0g, bean cake 105.0g, NH4Cl 6.0g, H2O 1000mL. The optimum fermentation condition was incubated for 4d in the condition of pH 5.0 and temperature 30 degrees C.

Aspergillus niger↗
PubMedDate not supplied

[Use of a preparation from fungal pectin lyase in the food industry].

A new enzyme preparation of fungal pectin lyase (EC 4.2.2.10) was shown to be useful for the production of cranberry juice and clarification of apple juice in the food industry. A comparative study showed that the preparation of pectin lyase is competitive with commercial pectinase products. The molecular weight of homogeneous pectin lyase was 38 kDa. Properties of the homogeneous enzyme were studied. This enzyme was most efficient in removing highly esterified pectin.

Beverages↗
PubMedDate not supplied

[Effectiveness of enzyme preparations of fodder in the degradation of nonstarch polysaccharides from grain substrates].

The effects of commercial and laboratory preparations were compared in the course of treatment of components of compound fodder. The most potent preparations were selected for the treatment of soybean flower, sunflower meal, and wheat and barley flour. Preparation 181-1008, which had a high proteinase activity, provided the highest yield of protein from soybean flour and sunflower meal. Preparations aGA, AG20X, and VR, characterized by high activities of pectinase and alpha-galactosidase, as well as laboratory preparation B2000Mix with a high activity of alpha-galactosidase, provided the highest yield of sugars from soybean flour. Preparations with high alpha-galactosidase activity were the most potent in hydrolyzing soluble carbohydrates from soybean flour. The highest yield of reducing sugars was observed after treatment of wheat and barley flour with preparations B2000Mix and aGa. Xylanase activity of these preparations was lower than that of preparations 3.130.2 and TG20X. Preparations 3.130.2 and TG20X were the most potent in hydrolyzing wheat middlings.

Animal Feed↗
PubMed1991

[Polysaccharides from Nerium oleander: structure and biological activity].

A water extraction of crushed leaves of Nerium oleander yielded 2.3% of a crude polysaccharide. The main fraction (67%) represents a pectic polysaccharide mainly composed of galacturonic acid besides rhamnose, arabinose and galactose. The polysaccharide structure was characterized by NMR, mild acid- and pectinase treatment combined with GC-MS analyses. In vivo tests for a possible antitumor activity did not result in a significant action. Investigation of immunomodulating activity brought some indications for mitogenic activity and a weak macrophage-mediated cytotoxicity. Increase of phagocytosis could not be doubtlessly assigned to the polysaccharide due to the high amount of endotoxin in the homogenous fraction OLE 2.

Animals↗
PubMed1991

[Studies on water soluble polysaccharides isolated from Tribulus terrestris L--purification and preliminary structural determination of heteropolysaccharide H].

Crude polysaccharides extracted from the stem and leaf of Tribulus terristris L after the removal of crude saponins are a mixture of heteropolysaccharides composed of Ara, Rha, Xyl, GalA, Gal, Glc and Man in molar ratios of 6.0:2.1:1:3.6:3.4:7.7:2.9. A homogeneous polysaccharide H obtained by gradation and purification contains Ara, Rha, Xyl, GalA. Gal and Glc. in molar ratios of 1.6:2.4:0.1:3.5:1.3:1. Its molecular weight was found to be 1 x 10(5). By means of pectinase and beta-D-galactosidase enzymolysis, periodate oxidation, Smith degradation, partial hydrolysis with acid, methylation, GC and GC-MS, the H contains alpha-D-GalA (1-4) and L-Rha (1-2) probably linked alternately as main chain with some L-Rha (1-2) side chains.

Drugs, Chinese Herbal↗
PubMed1990

Purification and characterization of polygalacturonases produced by the hyphal fungus Aspergillus niger.

Five endo-polygalacturonases (poly(1,4-alpha-D-galacturonide) glycanohydrolase, EC 3.2.1.15) and one exo-polygalacturonase (poly(1,4-alpha-D-galacturonide) galacturonohydrolase, EC 3.2.1.67) were isolated from a commercial pectinase preparation derived from Aspergillus niger. All five endo-enzymes could be purified to homogeneity by affinity chromatography on cross-linked alginate, ion-exchange chromatography, chromatofocusing, and gel permeation chromatography. The exo-polygalacturonase was only partially purified but free from endo-polygalacturonase activity. The two most abundant endo-polygalacturonases (endo-I and endo-II), with molecular masses of 55 and 38 kDa, respectively, are quite different with respect to their isoelectric point, specific activity, mode of action on oligomeric substrates, and amino acid composition. The physicochemical properties of the other three endo-polygalacturonases (endo-IIIA, endo-IIIB, and endo-IV), present in low amounts, are quite similar to those of the endo-I type. The pH optima of all these endo-polygalacturonases are in the range of 4.3-4.9.

Alginates↗
PubMed1987

Pectinolytic activity of revertants of auxotrophic strains of Aspergillus niger.

From conidia of 4 different auxotrophic A. niger strains 400 spontaneous revertants (100 from each strain) were obtained, and in one case additionally 100 revertants induced by mutagens (UV+NTG). The revertants showed a considerable differentiation with regard to the total pectinolytic activity. Its highest increase occurred in revertants originating from auxotrophs greatly predisposed to synthesize pectinases. In the case of revertants induced by mutagenes an increase in the frequency of their formation was observed, as well as an increased participation of revertants with higher pectinolytic activity compared to both their initial auxotrophic and prototrophic strain.

Aspergillus niger↗
PubMed1989

Isolation and cultivation of protoplasts of Caloglossa leprieurii.

Protoplasts, as important media in genetic engineering, had been isolated from some genera of seaweeds in the beginning of this decade. Using a mixed enzyme solution composed of 3% Sea snail enzyme, 3% Cellulase Onozuka R-10, 1% Macerozyme and 0.5% Pectinase, viable protoplasts were isolated from Caloglossa leprieurii (Mont) J. Ag. (Ceramiales, Rhodophyta). The viability of protoplast was determined by its exclusion of Evans Blue stain. The absence of cell walls were observed in the protoplasts, and were determined by Calcofluor White, reduced osmolarity, electron microscopic examination and self-fusion. About half of the protoplasts survived and divided at a high rate when they were cultivated in a thin liquid layer of modified medium No.5 (MES as basic medium, supplemented with MS medium, vitamins and 1ppm IAA, 1.5 ppm KT). Regenerated plantlet appeared after 45 days. Tetrasporangia appeared in the blade of some regenerated plants after 4 months. Due to its properties of Being large, polynucleal and regenerative, protoplasts of C. leprieurii offer a good prospect in the field of cell fusion and genetic operation of seaweeds.

Cell Division↗
PubMed1989

[Macrophage respiratory burst-triggering activity of transparent and opaque colonial variants of Mycobacterium avium complex].

The two types of colonial variants of Mycobacterium avium complex, SmT (smooth, transparent, irregular) and SmD (smooth, opaque, dome-shaped) variants, were examined for their triggering activity for macrophage (M phi) respiratory burst, based on chemiluminescence (CL). SmD variants elicited an intense CL from zymosan A-induced M phi s in a dose-dependent manner, although SmT variants induced much lower M phi CL. The M phi s could steadily phagocytose SmT variants, although the phagocytizing rate was considerably lower compared to the case of SmD variants. Treatments of SmD variants with Tween 80, pronase and some endoglycosidases such as alpha-amylase, cellulase, dextranase and pectinase, heating (100 degrees C, 15 min), and delipidation by CHCl3-methanol extraction resulted in a marked reduction in the M phi CL-triggering activity of the SmD variants. Thus, the M phi CL-triggering ligand(s) seems to possess glycolipoprotein-like moieties. Tween 80-treatment of SmT variants, which is known to deprive the polysaccharide outer layer specific to the colonial variants, failed to recover the M phi CL-triggering activity of SmT variants. Therefore, the remarkably reduced M phi CL-triggering ability of the SmT variants may be caused by the extremely lowered expression of the M phi CL-triggering ligands rather than by masking of the CL-triggering ligands by SmT-specific outer layer.

Animals↗
PubMedDate not supplied

[Admixtures of antibiotic substances in enzyme preparations of microbial origin intended for use as food additives].

A group of enzymtic preparations, mainly of the Soviet make were investigated for the presence of antibiotic substances admixtures. Altogether 25 preparations obtained from molds, actinomycetes, bacteria and yeast were studied. The results showed that 18 preparations contained antibiotic substances in an amount of 0.6-1300 U, equivalent to oxytetracycline units per 1 g. Most often antibiotics were present in preparations of the pectinase and protease group. In the group of glucoamylase the antibiotic activity was uncovered in a single preparation. Procedures employed in determining the antibiotic activity of enzymatic preparations is described and the possible role of antibiotics in the manifestations of their toxic properties discussed.

Actinomycetales↗
PubMed1983

Cellulolytic enzymes associated with the fruit rots of Citrus sinensis caused by Aspergillus aculeatus and Botryodiplodia theobromae.

Botryodiplodia theobromae and Aspergillus aculeatus were inoculated in carboxymethylcellulose (CMC) medium and on filter papers. Hydrolysis of the CMC medium and degradation of the filter papers were observed, indicating the production of C1 and Cx cellulases by the two rot pathogens. The C1 and Cx enzymes were also detected in filtrates of rotted orange fruits obtained by infection with the two pathogens. The cellulases could not induce rot development on their own. However, when they were added to pectinases in an enzyme inoculum, the incubation period for inducing rot development was shorter, thus establishing a secondary role for the cellulases in the rot development. Optimum conditions for the action of the cellulases included a neutral pH and temperature ranging from 25 to 30 degrees C.

Aspergillus↗
PubMed1982

[Enzymatic release of sedimentary bacteria in the presence of antibiotics].

Polysaccharases release microorganisms from their natural seat, marine sediments for example. The enzymatic activity works both on the microbial adherence polysaccharides and on the support surfaces (cellulose, pectine, etc.). Dosages of glucose confirm polysaccharase activity. An association of bacitracine, thiophenicol and a few enzymes: cellulase, pectinase, amyloglucosidase, alpha amylase, hyaluronidase, release a considerable number of bacteria. The culture on specific mediums confirm the specificity of this release. E. coli polyresistant strain where isolated by amylo-glucosidase, glucuronidase association in a mixture of thiophenicol and bacitracine. Bacillus and other Gram positive bacteria are frequently isolated by this method. The number of colonizer microorganisms on solid media are considerably higher with sediments treated by enzymes, or by enzyme, antibiotic mixtures, than with untreated ones.

Bacitracin↗