Multiple forms of pectic lyases and polygalacturonase from<i>Fusarium oxysporum</i>f,.sp.<i>radicis lycopersici</i>: regulation of their synthesis by galacturonic acid

Guevara, Marcial; Estévez, Pilar; González-Jaén, M. Teresa

doi:10.1139/m97-034

Cited by 13 publications

(4 citation statements)

References 33 publications

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“…PL is known to have an absolute requirement for Ca 2+ [23]. Clones with homology to PL are reported to be particularly abundant in banana pulp, and this suggests a significant role for PL activity in wall disassembly during ripening in the pulp [24].…”

Section: Discussionmentioning

confidence: 99%

Postharvest calcium chloride treatments do not help to increase shelf-life of bananas

Perera¹,

Karunaratne²

2002

Fruits

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Postharvest calcium chloride treatments do not help to increase shelf-life of bananas.Abstract -Introduction. Calcium chloride (CaCl 2 ) treatment has been shown to increase the shelf-life of fruits, mainly through making cell walls less accessible to pathogens and softening enzymes. Materials and methods. Bananas of four cultivars ['Ambon' (AAA), 'Embul' (AAB), 'Kolikuttu' (AAB) and 'Seenikehel' (ABB)] were dipped in or pressure infiltrated with 4% CaCl 2 . To determine the effect of exogenous ethylene on treated fruits, they were ripened with exogenous ethylene. Ca 2+ in cell wall fractions were monitored by atomic absorption spectrophotometry. Cup plate assays were performed to determine pectinase activity. Results and discussion. Pressure infiltration accelerated ripening and disease, and reduced firmness (P < 0.05). However, when exposed to ethylene, CaCl2 pressure-infiltrated bananas were insignificantly firmer than distilled water-infiltrated and ethylene-ripened bananas, showing a significant interaction (P < 0.05) between infiltration treatments and ethylene ripening. There was no consistent increase in covalently bound pectin of cell walls as seen in fruits that respond positively to CaCl 2 . Firmness reduction and ripening acceleration by Ca 2+ treatment cannot be explained if polygalacturonase (PG) (known to be inhibited by Ca 2+ ) was the dominant pectinase. Enzyme assays gave evidence of PG activity. When ammonium oxalate (known to bind Ca 2+ ) was eliminated from the test medium, pectinase activity increased with increasing pH (pH 5 to 9). The presence of a pectinase enzyme which exhibits activity in the presence of Ca 2+ is apparent. Conclusion. Ca 2+ does not appear to influence cell wall structure of bananas but appears to influence ripening physiology. Sri Lanka / Musa (fruits) / storage / calcium chloride / postharvest physiology / postharvest decay / polygalacturonase Le traitement au chlorure de calcium après récolte ne permet pas d'augmenter la durée de conservation des bananes.Résumé -Introduction. Le traitement au chlorure de calcium (CaCl2) permettrait d'augmenter la durée de conservation des fruits, principalement en rendant les parois cellulaires moins accessibles aux organismes pathogènes et aux enzymes de ramollissement. Matériel et méthodes. Les bananes de quatre cultivars ['Ambon' (AAA), 'Embul' (AAB), 'Kolikuttu' (AAB) et 'Seenikehel' (ABB)] ont été immergées dans une solution à 4 % de CaCl 2 ou soumises à une infiltration sous pression avec cette solution. L'effet de l'éthylène exogène sur les fruits traités a été testé lors de leur mûrissement. La présence de Ca 2+ dans des fragments de paroi cellulaire a été suivie par spectrophotométrie en absorption atomique. Des analyses ont permis de déterminer l'activité des pectinases. Résultats et discussion. Les infiltrations sous pression ont accéléré la maturation et le développement de maladies, et ont diminué la fermeté (P < 0,05). Cependant, exposées à l'éthylène, les bananes infiltrées sous pression avec du CaCl 2 ont été aussi f...

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Section: Discussionmentioning

confidence: 99%

Postharvest calcium chloride treatments do not help to increase shelf-life of bananas

Perera¹,

Karunaratne²

2002

Fruits

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“…Mixtures of high sugar content wastes such as banana (13.2%) and mango (19.5%) peels with sugar cane bagasse resulted in increase in the Pg and Pl production compared to fermentations in which the bagasse was not used (Table 1). It is known that the synthesis of pectinases by fungi is subject to catabolic repression by high free sugar concentration affecting inducible and constitutive enzymes (1,19). On the other hand, the consistence and size of particles in media composed of banana and mango peels interfered in their packing during the fermentation, since the bed remained static (nonmixed system), affecting the gas and heat exchange within the system (27).The addition of fibrous material as sugar cane bagasse increased the interparticle spacing, possibly increasing the aeration and diffusion of nutrient and enzyme, as shown by Mitchell et al (26).…”

Section: Production Of Pectinases By Ssfmentioning

confidence: 99%

Pectinase production by Penicillium viridicatum RFC3 by solid state fermentation using agricultural wastes and agro-industrial by-products

Silva¹,

Martins²,

Silva³

et al. 2002

Braz. J. Microbiol.

112

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Pectin lyase and polygalacturonase production by newly isolated Penicillium viridicatum strain Rfc3 was carried out by means of solid state fermentation using orange bagasse, corn tegument, wheat bran and mango and banana peels as carbon sources. The maximal activity value of polygalacturonase (Pg) (30U.g-1) was obtained using wheat bran as carbon source while maximal pectin lyase (Pl) (2000 U.g-1) activity value was obtained in medium composed of orange bagasse. Mixtures of banana or mango peels with sugar cane bagasse resulted in increased Pg and Pl production compared to fermentations in which this residue was not used. The mixture of orange bagasse and wheat bran (50%) increased the production of Pg and Pl to 55 U.g-1 and 3540 U.g-1 respectively. Fractions of Pg and Pl, isolated by gel filtration in Sephadex G50, presented optimum activity at pH 5.0 and 10.5 respectively. Maximal activity of Pg and Pl fractions was determined at 55ºC and 50ºC respectively. Pg was stable in neutral pH range and at 40ºC whereas Pl was stable in acidic pH and at 35ºC, for 1 h.

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“…On the other hand, when these data are compared with those in Figure 2(c) , it is observed that the maximum PL activity occurred in all three media when the medium pH reached 5.0 ( Figure 2(c) ). Other authors have described pH 5.0 as the best for fungal polygalacturonase production [ 17 – 19 ], whereas pectin lyase production was highest at neutral-alkaline pH [ 20 – 22 ].…”

Section: Resultsmentioning

confidence: 99%

“…This variation in the isoforms of extracellular enzymes can be attributed to many factors, such as the presence of several genes, different degrees of glycosylation, posttranscriptional processing, or proteolysis after secretion [ 14 , 30 ]. Multiple isoforms of secreted pectinases are usually obtained in fungal culture media [ 11 , 22 , 31 , 32 ] since the infection of host living tissue by a pathogen and colonization of plant cells decaying by saprophytic microorganisms is facilitated if a sufficient quantity and a number of isoform types of pectinase are produced [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

Production of Pectate Lyase byPenicillium viridicatum RFC3in Solid-State and Submerged Fermentation

Ferreira

Silva

et al. 2010

International Journal of Microbiology

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Pectate lyase (PL) was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1 : 1 w/w), or orange bagasse, wheat bran and sugarcane bagasse (1 : 1 : 0.5 w/w), and in a submerged liquid culture with orange bagasse and wheat bran (3%) as the carbon source. PL production was highest (1,500 U mL−1 or 300 Ug−1 of substrate) in solid-state fermentation (SSF) on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF) was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled PL I′, II′, III′, IV′, and VII′. Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at 35°C, but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to 45°C. Crude enzyme from SmF and PL III′ showed thermophilic profiles of activity, with maximum activity at 60 and 55°C, respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0–10.0 and PL III was most stable in the pH range 4.0–7.0. Crude enzyme from SmF retained 70%–80% of its maximum activity in the acid-neutral pH range (4.0–7.0), but PIII showed high stability at alkaline pH (7.5–9.5). PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1 h at 55°C. The differing behavior of the enzymes with respect to pH and temperature suggests that they are different isozymes.

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Multiple forms of pectic lyases and polygalacturonase fromFusarium oxysporumf,.sp.radicis lycopersici: regulation of their synthesis by galacturonic acid

Cited by 13 publications

References 33 publications

Postharvest calcium chloride treatments do not help to increase shelf-life of bananas

Postharvest calcium chloride treatments do not help to increase shelf-life of bananas

Pectinase production by Penicillium viridicatum RFC3 by solid state fermentation using agricultural wastes and agro-industrial by-products

Production of Pectate Lyase byPenicillium viridicatum RFC3in Solid-State and Submerged Fermentation

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