Enzyme activities and pectin breakdown of sapodilla submitted to 1-methylcyclopropene

The objective of this work was to investigate the influence of 1-methylcyclopropene (1-MCP) at 300 nL L-1 on activities of cell wall hidrolytic enzymes and pectin breakdown changes which Sapodilla (Manilkara zapota cv. Itapirema 31) cell wall undergoes during ripening. Sapodilla were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 hours and then, stored under a modified atmosphere at 25º C for 23 days. Firmness, total and soluble pectin and cell wall enzymes were monitored during storage. 1-MCP at 300 nL L-1 for 12 hours delayed significantly softening of sapodilla for 11 days at 25º C. 1-MCP postharvest treatment affected the activities of cell wall degrading enzymes pectinmethylesterase and polygalacturonase and completely suppressed increases in beta-galactosidase for 8 days, resulting in less pectin solubilization. Beta-galactosidase seems relevant to softening of sapodilla and is probably responsible for modification of both pectin and xyloglucan-cellulose microfibril network.

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Cell wall biochemistry of sapodilla (Manilkara zapota) submitted to 1-methylcyclopropene

Brazilian Journal of Plant Physiology ◽

10.1590/s1677-04202008000200001 ◽

2008 ◽

Vol 20 (2) ◽

pp. 85-94 ◽

Cited By ~ 8

Author(s):

Patrícia L.D. Morais ◽

Maria R.A. Miranda ◽

Luis C.O. Lima ◽

José D. Alves ◽

Ricardo E. Alves ◽

...

Keyword(s):

Cell Wall ◽

Ethylene Production ◽

Low Temperatures ◽

Modified Atmosphere ◽

Neutral Sugar ◽

Manilkara Zapota ◽

Modified Atmospheres ◽

Climacteric Fruit ◽

Ethylene Antagonist ◽

Physiological And Biochemical

Sapodilla (Manilkara zapota) is a climacteric fruit that ripens shortly after harvest. Studies on its conservation during storage have been mainly restricted to using low temperatures and modified atmospheres. In this study we investigated the influence of 1-methylcyclopropene (1-MCP) on the physiological and biochemical changes that sapodilla cell wall undergoes during ripening and evaluated its potential to preserve sapodilla fruits at postharvest. Fruits were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 h and then stored under a modified atmosphere at 25ºC for 23 d. 1-MCP significantly delayed softening of sapodilla for 11 d as a consequence of inhibition of cell wall degrading enzyme activities, and thus 1-MCP-treated fruit exhibited a less extensive solubilization of polyuronides, hemicellulose and of free neutral sugar when compared to control fruit. Results suggest that delayed softening of sapodilla is largely dependent on ethylene production and perception.

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A rationale for the development of feed enzyme products for ruminants

Canadian Journal of Animal Science ◽

10.4141/a02-103 ◽

2004 ◽

Vol 84 (1) ◽

pp. 23-36 ◽

Cited By ~ 28

Author(s):

K. A. Beauchemin ◽

D. Colombatto ◽

D. P. Morgavi

Keyword(s):

Cell Wall ◽

Enzyme Activities ◽

Plant Cell Wall ◽

Biochemical Characterization ◽

Feedlot Cattle ◽

Wall Material ◽

Cell Wall Degrading Enzymes ◽

Enzyme Product ◽

Exogenous Enzymes

The use of exogenous cell wall degrading enzymes is an emerging technology that shows potential in terms of improving feed utilization by ruminants. This review discusses current information related to enzyme product formulation for ruminants, and addresses the conditions necessary to ensure effective and consistent in vivo results of providing feed enzymes to ruminants. Research has demonstrated that, in some cases, adding fibrolytic enzymes to dairy cow and feedlot cattle diets improves cell wall digestion and, consequently, weight gain or milk production are enhanced. However, considerable research is required to develop more effective enzyme products and to ensure consistency of responses in vivo. There is a need to identify the key enzyme activities involved in the positive responses observed in vivo and these enzyme activities should be assessed using a temperature and pH representative of the conditions in the rumen. However, to date, it has not been possible to accurately evaluate exogenous enzymes based only on their biochemical characterization because the model substrates used do not represent the complexity of plant cell wall material. In vitro techniques using feed substrates, buffer and ruminal fluid can be used more reliably as a bioassay to predict in vivo response to exogenous enzymes, however, other factors, including under or over-supplementation of enzyme activity, method of providing the enzyme product to the animal, composition of the diet, and the target animals must also be considered. Key words: Cattle, digestion, fibre digestion, enzymes, cellulases, hemicellulases

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Some enzymes present in the walls of mesophyll cells of tobacco leaves

Biochemical Journal ◽

10.1042/bj1510141 ◽

1975 ◽

Vol 151 (1) ◽

pp. 141-144 ◽

Cited By ~ 26

Author(s):

K H Yung ◽

D H Northcote

Keyword(s):

Cell Wall ◽

Acid Phosphatase ◽

Horseradish Peroxidase ◽

Malate Dehydrogenase ◽

Enzyme Activities ◽

Incubation Medium ◽

Time Course ◽

Mesophyll Cells ◽

Cell Wall Enzymes ◽

The Difference

Cell-wall enzymes were assayed by the difference between enzyme activities in the whole cell and the protoplast. Both peroxidase (85.2%) and acid phosphatase (21.9%) were located in the wall. However, malate dehydrogenase was found only in the protoplast. A study of the time-course of the release of peroxidase and malate dehydrogenase into the incubation medium from cells either treated with cellulase or untreated, also indicated that peroxidase and not malate dehydrogenase was located in the wall. Only two anodic isoenzymes of peroxidase were present in the cell wall. These were more negatively charged than those of horseradish peroxidase.

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