Extracellular and intracellular polygalacturonic acid trans-eliminases of Erwinia carotovora

Moran, Francis; Nasuno, Seiichi; Starr, Mortimer P.

doi:10.1016/0003-9861(68)90138-0

Cited by 187 publications

(100 citation statements)

References 29 publications

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“…Cultures were centrifuged at 2500 g and supernatants were used for pectate-lyase activity assays. Pectate-lyase activity was determined by spectrometric monitoring of the degradation of PGA to unsaturated products at 235 nm (Moran et al, 1968) at 37 uC in PL buffer (50 mM Tris/HCl, pH 8.5, 0.1 mM CaCl 2 , 0.05 % PGA).…”

Section: Methodsmentioning

confidence: 99%

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

2014

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Dickeya dadantii is a phytopathogenic enterobacterium that causes soft rot disease in a wide range of plant species. Maceration, an apparent symptom of the disease, is the result of the synthesis and secretion of a set of plant cell wall-degrading enzymes (PCWDEs), but many additional factors are required for full virulence. Among these, osmoregulated periplasmic glucans (OPGs) and the PecS transcriptional regulator are essential virulence factors. Several cellular functions are controlled by both OPGs and PecS. Strains devoid of OPGs display a pleiotropic phenotype including total loss of virulence, loss of motility and severe reduction in the synthesis of PCWDEs. PecS is one of the major regulators of virulence in D. dadantii, acting mainly as a repressor of various cellular functions including virulence, motility and synthesis of PCWDEs. The present study shows that inactivation of the pecS gene restored virulence in a D. dadantii strain devoid of OPGs, indicating that PecS cannot be de-repressed in strains devoid of OPGs.

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Section: Methodsmentioning

confidence: 99%

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

2014

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“…Pectate lyase activity was measured by using the method described by Moran et al (1968) with some modifications. The assay carried out in a mixture containing 4 mM sodium acetate buffer (pH 4.5), 0.3 ml polygalacturonic acid (PGA, 1 % aqueous solution adjusted to pH 4.5) and 0.1 ml enzyme preparation in 1 ml total reaction volume.…”

Section: Assay Of Pectate Lyasementioning

confidence: 99%

“…The increase in the absorbance against the control with preboiled enzyme was taken as a measure of the pectate lyase activity. All the calculations were carried out according to Moran et al (1968) and 1 unit of pectate lyase activity was expressed as the amount of enzyme required to liberate 1 nmol of aldehyde groups from PGA per minute under the conditions of the enzyme assay.…”

Section: Assay Of Pectate Lyasementioning

confidence: 99%

Composite coating of alginate-olive oil enriched with antioxidants enhances postharvest quality and shelf life of Ber fruit (Ziziphus mauritiana Lamk. Var. Gola)

et al. 2015

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The present study has been carried out to evaluate the effect of a composite edible coating of 2 % Sodium alginate and 0.2 % Olive oil with combination of 1 % ascorbic acid and 1 % citric acid on the post harvest nutritional quality and shelf life of Ber fruit stored at 25 ± 2°C and 65 % R.H. The coatings reduced the decay occurrence, weight loss, accumulation of total soluble solids (TSS) and total sugars in Ber fruit and enhanced the level of antioxidants. The delayed activity of polygalacturonase (PG), Pectate lyase (PL) and Pectin methyl esterase (PME) was noticed in coated fruits than that of the control fruit indicating the reduced softening and ripening process. These findings suggest that the composite edible coating tested under the current study has the potential to control decaying incidence of Ber fruit, extends its storage life and also improves its valuable nutritional characteristics.

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“…For most of the assays of lyase activity the reaction mixture contained: sodium pectate or pectin N.F., 0.25o/b (w/v); CaCI,. 2H,O, 0.25 mM; and 0.05 M-Tris/HCl buffer, pH 8.6 (Moran, Nasuno & Starr, 1968) ; to correlate the change in viscosity with increase in unsaturated and reducing groups the concentrations of sodium pectate and CaCI,. 2H20 were increased to 0.5 % (w/v) and 0.4 mM respectively.…”

Section: Assay Of Pectic Enzymesmentioning

confidence: 99%

Pectic Enzymes of Pigmented Strains of Clostridium

Lund¹,

Brocklehurst²

1978

Journal of General Microbiology

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59The pectic enzymes of six strains of pigmented, pectolytic clostridia isolated from potatoes were examined and compared with those strains of Clostridium felsineum and Clostridium aurantibutyricum using cup-plate assays. The organisms could be divided into two groups. Group I consisted of the potato isolates and the strain of C. aurantibutyricum; these formed pectic lyase enzymes and pectinesterase but no pectic hydrolase. Group 2 consisted of eight strains of C. felsineum (and one culture labelled Clostridium roseum) ; these formed pectic lyase and pectic hydrolase but no detectable pectinesterase. Viscometric studies and analyses of degradation products of pectate formed by enzymes of four representative strains from group I and two strains from group 2 showed that all these clostridia formed endopectate lyase enzymes; studies of one enzyme preparation showed that the pH optimum was about 9-5. In addition, the group 2 organisms formed endopolygalacturonase and probably also exopolygalacturonase. I N T R O D U C T I O NDuring studies of bacterial soft rot of potatoes, pectolytic clostridia have regularly been detected in rotting tissue (Lund, 1972;Lund & Kelman, 1977). Although the primary cause of this spoilage is usually Erwinia carotovora, some of these pectolytic clostridia cause rapid maceration of potato tissue and undoubtedly enhance the effect of E. carotovora (Rudd-Jones & Dowson, 1950). The pectolytic clostridia associated with rotting potatoes probably belong to several species (Lund, 1972) and include a group of bacteria which form a pink pigment. Apart from the colour of the pigment, these clostridia have many properties in common with Clostridium felsineum (B. M. Lund & G. M. Wyatt, unpublished). The purpose of this work was to determine whether pigmented clostridia isolated from potatoes differed from C. felsineum or another pigmented clostridium, Clostridium aurantibutyricum, in the type of pectic enzymes formed.Of the bacterial enzymes which depolymerize pectic substances, the most widely reported are those with lyase activity, although bacteria from several genera form enzymes which hydrolyse pectate (see Rombouts, 1972;Rombouts & Pilnik, 1972;Fogarty & Ward, 1974

show abstract

Extracellular and intracellular polygalacturonic acid trans-eliminases of Erwinia carotovora

Cited by 187 publications

References 29 publications

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

Inactivation of pecS restores the virulence of mutants devoid of osmoregulated periplasmic glucans in the phytopathogenic bacterium Dickeya dadantii

Composite coating of alginate-olive oil enriched with antioxidants enhances postharvest quality and shelf life of Ber fruit (Ziziphus mauritiana Lamk. Var. Gola)

Pectic Enzymes of Pigmented Strains of Clostridium

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