Partial hydrolysis of polygalacturonic acid with a purified alpha-1,4-endopolygalacturonase yielded oligogalacturonides and trace amounts of a series of modified oligogalacturonides. Three of the minor products were isolated and identified as oxidized oligogalacturonides possessing termini of galactaric acid. Oxidation of indole-3-acetic acid by peroxidases was activated by oxidized oligogalact...

Basidiospore germlings of the cowpea rust fungus (Uromyces vignae) penetrate the epidermal cell wall of the nonhost plant Vicia faba. In order to characterize the wall structure of the penetration site, leaves were high pressure frozen, freeze substituted, and embedded in appropriate resins. With antibodies against epitopes present in pectin, polygalacturonic acid, xyloglucan, and callose, we s...

thirty-five fungal strains which isolated from vegetable wastes, were screened for the use of polygalacturonic acid as the sole carbon source. twenty-five isolates were positive for polygalacturonase activity in cup-plate assay, as evidenced by clear hydrolysation zones. the most productive strain was determined by measuring clear zones formed around colonies stained with ruthenium red. the hig...

Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results sugg...

Pectins, forming a matrix for cellulose and hemicellulose, determine the mechanics of plant cell walls. They undergo salient structural changes during their development. In the presence of divalent cations, usually calcium, pectins can form gel-like structures. Because of their importance they have been the subject of many force spectroscopy experiments, which have examined the conformational c...

A particulate preparation obtained from Phoseolus aweus shoots contains an enzyme capable of transferring the 14Clabeled methyl groups from S-adenosyl-L-methionine to the carbozyl groups of polygalacturonic acid, which seems to be present in the same particulate material. The introduction of the methyl ester groups is optimal at pH 6.8 and does not require divalent ions. S-IV-Methyltetrahydrofo...

Bacteroides thetaiotaomicron, an obligate anaerobe found in high numbers in human colons, can utilize a variety of polysaccharides. To determine which type of polysaccharide contributes most to the nutrition of B. thetaiotaomicron in vivo, we isolated and characterized transposon-generated mutants deficient in the ability to use different polysaccharides. Some mutants were deficient in polysacc...