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PubMed2003

Distribution of pectins in the pollen apertures of Oenothera hookeri.velans ster/+ster.

Cell wall pectins are some of the most complex biopolymers known, and yet their functions remain largely mysterious. The aim of this paper was to deepen the study of the spatial pattern of pectin distribution in the aperture of Oenothera hookeri.velans ster/+ster fertile pollen. We used "in situ" immunocytochemical techniques at electron microscopy, involving monoclonal antibodies JIM5 and JIM7 directed against pectin epitopes in fertile pollen grains of Oenothera hookeri.velans ster/+ster. The same region was also analyzed by classical cytochemistry for polysaccharide detection. Immunogold labelling at the JIM7 epitope showed only in mature pollen labelling mainly located at the intine endo-aperture region. Cytoplasmic structures near the plasma membrane of the vegetative cell showed no labelling gold grains. In the same pollen stge the labelling at the JIM5 epitope was mostly confined to a layer located in the limit between the endexine and the ektexine at the level of the border of the oncus. Some tubuli at the base of the ektexine showed also an accumulation of gold particles. No JIM5 label was demonstrated in the aperture chamber and either in any cytoplasmic structure of the pollen grains. The immunocytochemical technique, when compared with the traditional methods for non-cellulose polysaccharide cytochemistry is fare more sensitive and allows the univocal determination of temporal and spatial location of pectins recognized by the JIM7 and JIM5 MAbs.

Antibodies, Monoclonal↗

PubMed1985

Colonic bacterial flora and serum cholesterol: alterations induced by dietary citrus pectin.

The influence of dietary pectin on blood lipids and stool bacterial flora, enzyme activity, and physical properties was investigated. Fifteen grams of citrus pectin were added to the normal diets of 10 subjects. A decrease in serum cholesterol was observed after 2 wk of dietary supplementation, but was not statistically significant after the 3rd wk. Fecal bacterial flora was modified by pectin; anaerobic bacteria increased and aerobic bacteria increased. No change in stool bacterial 7 alpha dehydroxylase or cholesterol dehydrogenase activity was observed. The daily stool output, pH, and water content were not influenced by the addition of pectin to the diet.

Adult↗

PubMed1987

Effects of differing purified cellulose, pectin and hemicellulose fiber diets on mucosal morphology in the rat small and large intestine.

The effects of increasing amounts of differing single-fiber sources in chemically-defined and nutritionally-equivalent diets on morphometric measurements of the rat small and large intestinal mucosa were examined. Male Wistar rats received a fiber-free diet, or diets containing 4.5% or 9.0% cellulose, pectin, or hemicellulose. Cellulose and pectin increased jejunal (but not ileal) villus and crypt heights, whereas hemicellulose increased ileal (but not jejunal) mucosal height. Moreover, cellulose and pectin (but not hemicellulose) increased crypt heights in cecum and proximal (but not distal) colon. Parallel increases in the mitotic index were seen with cellulose and pectin diets, but there was a decrease with hemicellulose, suggesting different mechanisms for altered patterns of cell renewal induced by orally-administered single-fiber sources. These changes indicate that differing single-fiber sources exert differential structural effects along the length of the small and large intestine in the rat.

Animals↗

PubMed1979

[Late hypoglycaemia in chemical diabetes. Abnormalities of pancreatic glucagon secretion and effect of pectine (author's transl)].

Nineteen patients suffering from chemical diabetes either with (group A, ten cases) or without (group B, nine cases) reactive hypoglycaemia were included in the study and compared with seven control (group C). The following variables were measured over a 5 hour period during a standard oral glucose tolerance test (OGTT): (i) blood glucose by continuous monitoring; (ii) plasma insulin and glucagon levels by radioimmunoassay. Furthermore, in five diabetics of group A, the data from the standard OGTT were compared with those from a pectin-supplemented OGTT (9 g per square meter of body surface). Although the insulin response was similar glucagon levels were significantly higher (45.1 +/- 11.8 pmol/l) (p less than 0.01) in group B than in group A (9.6 +/- 1.3) and C (8.1 +/- 1.4 at 30 minutes). The high glucagon levels noted in group B may explain the absence of reactive hypoglycaemia. The pectin supplementation improved the OGTT pattern by blunting the blood glucose peak (p less than 0.05), and avoiding the reactive hypoglycaemia (p less than 0.01). The addition of pectin did not produce any significant effect on the insulin response while a significant increase in glucagon concentrations (p less than 0.05) was observed beyond the 150th minute. Therefore, the data suggest that pectin may improve the OGTT pattern by increasing the glucagon response in the late period of the test. The development of postprandial reactive hypoglycaemia seldom coincides with a plasma glucagon peak, while the absence of reactive hypoglycaemia tends to be associated with high levels of glucagon, as is the case in overt diabetes mellitus.

Adult↗

PubMedDate not supplied

[Multiple forms of pectin trans-eliminase from Verticillium dahliae Klebahn -- cotton wilt agent].

From the culture liquid filtrate of Verticillium dahliae--cotton wilt agent--pectin trans-eliminase (EC) was isolated. The enzyme was isolated and examined, using ultrafiltration, gel filtration, ion exchange chromatography, isoelectrofocusing, and electrophoresis. The fungus was found capable to produce several forms of pectin trans-eliminase that differed in their molecular weight, charge, synthesis and release regulation, substrate action (position of bonding breakdowns in the pectin polymer molecule). Pectin trans-eliminase activity was also detected in cell walls of the fungal mycelium. Possible origin of multiple forms of the enzyme is discussed.

Chromatography, Affinity↗

PubMed1981

Effect of two kinds of pectin and guar gum on 1,2-dimethylhydrazine initiation of colon tumors and on fecal beta-glucuronidase activity in the rat.

The effect of 5% low-methoxylated pectin, high-methoxylated pectin, and guar gum on 1,2-dimethylhydrazine initiation of colon cancer was investigated using groups of 30 rats. The growth of the rats in the different groups was very similar to that of control group fed a fiber-free diet. Both kinds of pectin increased the multiplicity of color tumors, whereas guar gum did not significantly influence carcinogenesis. Bacterial beta-glucuronidase activity in feces and colonic content was the same in pectin-fed rats and controls but significantly lower in the guar gum group. Thus, it was not related to the number of tumors in each group.

Adenocarcinoma↗

PubMed1980

[The effects of wheat bran and pectin on the oral glucose tolerance test in patients after gastric surgery (author's transl)].

In 23 patients previously operated on the stomach, the effect of pectin and wheat bran on the glucose tolerance test (G.T.T.) has been studied. If wheat bran had no significant effect on the glucose tolerance curve, pectin had a significant effect, lowering blood glucose value before the 90th minute (1,32 +/- 0,33 g/l as against 1,87 +/- 0,23 on the 30th minute) and elevating blood glucose value after the 90th minute of the G.T.T. (0.90 +/- 0,30 as against 0, 63 +/- 0,26 on the 120th minute). Therapeutic efficiency of pectin was confirmed in three patients who had symptoms of hypoglycaemia, which disappeared with the intake of 5 g of pectin before each meal.

Adult↗

PubMedDate not supplied

[Experimental and clinical studies of the effect of pectin on the causative agents of acute intestinal infections].

The effect of alimentary pectin obtained from different raw materials (apple, tomato, cotton-wool) on the causative agents of infectious diarrheal diseases, belonging to the genera Shigella, Salmonella, Klebsiella, Enterobacter, Proteus and Citrobacter, was studied under experimental conditions and in clinical observations. The study revealed that pectin, irrespective of raw material used for its production, produced an inhibiting effect on these microorganisms. This effect was most pronounced, both under experimental and clinical conditions, when 5% pectin solution was used. A rapid suppress of diarrhea and other manifestations of the infectious syndrome was observed in patients. The patients treated with pectin stayed in the hospital, on the average, 2-3 days less than the control group of patients treated with antibiotics and other chemotherapeutic preparations.

Acute Disease↗

PubMed1977

The influence of dietary pectin on the cholesterol content of egg-yolk and muscle and on various haematological indices in laying-hens.

Studies were undertaken to see if a commerical poultry diet, supplemented with 0, 2, 4 or 6% pectin would influence the cholesterol content of egg-yolk and muscle, the total lipid, cholesterol and protein contents of blood serum, and the erythrocyte count, packed cell volume and haemoglobin content of whole blood, in laying hens. The cholesterol content of the egg-yolk and muscle from birds given pectin was not significantly different from that of control hens. However, the birds which received the pectin weighed somewhat less than the controls at the end of the experiment, and produced fewer eggs, despite the same intake of digestible energy. Pectin treatment also resulted in higher erythrocyte counts, higher packed cell volumes and higher haemoglobin contents in the blood. The variation in the cholesterol content of egg-yolk was significantly lower within layers than between layers. This suggests that it should be possible to select for hens which produce eggs of lower cholesterol content, provided that other aspects of egg-production are not thereby negatively influenced.

Animal Feed↗

PubMedDate not supplied

Stoichiometry of pectin and glucose fermentation in Prevotella ruminicola.

Prevotella ruminicola is an important rumen pectinolytic bacterium. Strain 659 was grown anaerobically at pH 6.5 and temperature 39 degrees C in LF2 fermenters on media containing glucose or pectin (4 g/l) in order to determine its fermentation stoichiometry and growth parameters. Both substrates were utilized almost completely (> 90%). The growth on pectin was more rapid than on glucose. Pectin and glucose differed considerably in composition of fermentation end-products. Production of acetate was significantly higher when P. ruminicola 659 was grown on pectin, while production of other metabolites (formate, succinate, lactate) was lower than on glucose. Production of dry cell matter was significantly higher in cultures supplied with glucose. An increase in dry matter and protein yields calculated per carbon was not verified.

Acetates↗

PubMed1977

Effect of dietary fiber on complications of gastric surgery: prevention of postprandial hypoglycemia by pectin.

The dumping syndrome is a very troublesome problem to some patients after gastric surgery. Gel-forming carbohydrates have recently been used to modify glucose absorption. The addition of 14.5 g of pectin to a 50-g oral glucose load prevented the occurrence of hypoglycemic symptoms and maintained the blood glucose levels above control values by 64% at 90 min (P less than 0.002) and 46% at 120 min (P less than 0.01) in postgastric surgery patients whose 120-min values after 50 g of glucose alone had fallen below 50 mg per 100 ml (2.8 mmoles per liter). Breath H2 production, used as an index of bacterial fermentation of glucose, was abolished or reduced by pectin in all 5 cases in which this had previously occurred. A trial of 10 g of pectin per day prevented recurrent postprandial hypoglycemic attacks in the most severely affected individual. Pectin and perhaps other unabsorbable polysaccharides are likely to prove useful in the treatment of abnormal carbohydrate absorption after gastric surgery.

Adult↗

PubMed1997

Pectin coated hollow fiber polypropylene membranes.

The aim of this study was to prepare a composite membrane for the selective, extracorporeal removal of human LDL-cholesterol. Pectin coated on a porous polypropylene membrane (PP) was used as an active LDL adsorber. Three types of membrane preparations were performed: coating of native PP, coating after chemical etching and gamma-irradiated coated PP. Pectin coated fibers (PCF) were examined under scanning electron microscope (SEM) and tested for hydraulic permeability. As a result of the coating of native and etched PP membrane, pectin layers of various thicknesses (2-16 microm) and porosity were obtained. Irradiation by gamma rays gave no insoluble pectin layers.

Biocompatible Materials↗

PubMed1997

[Microbial and enzymatic extraction of pectin. A review].

Great amounts of agroindustrial wastes rich in polysaccharides, such as pectic substances, are produced worldwide. Some of these wastes are used for the production of pectin. Currently, pectin is extracted at industrial scale by physicochemical means, but lately new biotechnological alternatives have been developed. In this review, the principal characteristics of pectic substances and pectic enzymes are described. The traditional physicochemical method for the pectin extraction is described and the new biotechnological (microbial and enzymatic) methods for pectin extraction are discussed and commented as well.

Biotechnology↗

PubMed2001

The pectineal ligament: anatomical study and surgical applications.

The aim of this study was to reinforce the importance of the pectineal ligament in laparoscopic surgery for groin hernia and female urinary incontinence, particularly its anatomical importance in the myopectineal region. A morphologic study was conducted on 44 pectineal ligaments from 23 embalmed and one fresh human cadavers, together with a radiological study on four volunteer patients. Anatomical and histological findings confirm the fact that the ligament of Cooper represents a thickening of the pectineal fascia rather than a thickening from the periosteum. The pectineal ligament provides a landmark in each approach, open or laparoscopic, anterior or posterior surgery.

Aged↗

PubMed2004

Two Arabidopsis thaliana genes encode functional pectin methylesterase inhibitors.

We have identified, expressed and characterized two genes from Arabidopsis thaliana (AtPMEI-1 and AtPMEI-2) encoding functional inhibitors of pectin methylesterases. AtPMEI-1 and AtPMEI-2 are cell wall proteins sharing many features with the only pectin methylesterase inhibitor (PMEI) characterized so far from kiwi fruit. Both Arabidopsis proteins interact with and inhibit plant-derived pectin methylesterases (PMEs) but not microbial enzymes. The occurrence of functional PMEIs in Arabidopsis indicates that a mechanism of controlling pectin esterification by inhibition of endogenous PMEs is present in different plant species.

Amino Acid Sequence↗

PubMed1994

Purification of three pectin esterases from ripe peach fruit.

Three isoforms of pectin esterase (PE1-PE3) (pectin pectyl-hydrolase, EC 3.1.1.11.) were purified to homogeneity from ripe peach fruit (Prunus persica cv. Coronet). The three enzymes were basic proteins of M(r) 34,000 as determined by denaturing polyacrylamide gel electrophoresis but were separated by FPLC cation-exchange chromatography. The proteins were N-terminally blocked but amino acid sequences were obtained for peptides released from two of the three isoforms. The sequences revealed a threonine/lysine substitution in a comparison between isoform PE2/isoform PE3, and there were regions of sequence similarity with other plant pectin esterases. The proteins did not bind to concanavalin A and were not stained by the periodate-Schiff reagent suggesting a low or zero level of glycosylation. Polyclonal antisera to isoform PE3 also bound to isoforms PE1 and PE2. The study provides the enzyme protein sequence and immunological basis for an evaluation of the role of pectin esterases in normal and abnormal ripening of peach fruit.

Amino Acid Sequence↗

PubMed1999

Aspergillus kawachii produces an acidic pectin releasing enzyme activity.

A pectin-releasing (protopectinase, PPase) activity was found in a culture filtrate of Aspergillus kawachii IFO 4308. PPase activity was highest in the pH range of 2.0-2.5 and it was highly stable at 50 degrees C (85% of residual activity was found after a 10-h incubation in citrate-phosphate buffer, pH 3.0). Among other different enzyme activities, which are usually involved in plant cell-wall degradation, only polygalacturonase activity was detected. This result suggests that the PPase activity could correspond to a particular kind of polygalacturonase. Pectin extraction from lemon peels carried out at 50 degrees C for 2 h (pH 3.5) gave yields of ethanol-precipitated pectin equivalent to 17.4% of the initial total solids contained in the peels. Thus, this enzyme activity would allow carrying out a pectin extraction process at lower reaction pHs and higher temperatures in comparison with similar reports using other PPases. These properties seem to be very interesting from the practical point of view.

Journal Article↗

PubMed2002

Two pectin lyase genes, pnl-1 and pnl-2, from Colletotrichum gloeosporioides f. sp. malvae differ in a cellulose-binding domain and in their expression during infection of Malva pusilla.

Two pectin lyase genes, designated pnl-1 and pnl-2, were cloned from Colletotrichum gloeosporioides f. sp. malvae, a pathogen of round-leaved mallow (Malva pusilla). pnl-1 was isolated using cDNA from infected plant material; pnl-2 was isolated using cDNA from 3-day-old mycelia grown in mallow-cell-wall extract (MCWE) broth. pnl-1 is the first pectinase gene described thus far to encode a cellulose-binding domain (CBD), which is common in cellulases and xylanases, whereas pnl-2 encodes a pectin lyase that lacks a CBD. In pure culture, pnl-1 expression could be detected when purified pectin or glucose was the sole carbon source, but not when MCWE was the sole carbon source. The lack of pnl-1 expression appeared to be due to gene repression by some unknown factor(s) in the cell-wall extract. In contrast, expression of pnl-2 was detected in cultures when MCWE, but not when purified pectin or glucose, was the sole carbon source. In infected tissue, detection of pnl-1 expression by Northern-blot hybridization and by RT-PCR began with the onset of the necrotrophic phase of infection. Expression ofpnl-2 was not detectable by Northern-blot hybridization, but was observed byRT-PCR in both the biotrophic and necrotrophic phases of infection. The differences between pnl-1 and pnl-2 (i.e. pnl-1 encoding a CBD and differences in the expression patterns of both genes) may be related to the requirements of C. gloeosporioides f. sp. malvae to be able to grow in host tissue under the different conditions present during the biotrophic and necrotrophic phases of infection.

Amino Acid Sequence↗