Reactive oxygen and ethylene are involved in the regulation of regurgitant-induced responses in bean plants

Steinite, I.; Gailīte, Agnese; Ievinsh, Gederts

doi:10.1078/0176-1617-01098

Cited by 21 publications

(12 citation statements)

References 17 publications

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“…Many induction factors of PPO have been confirmed across many different species, such as pathogen invasion (Li and Steffens, 2002), attack of herbivorous insects (Steinite et al, 2004), influence of wounding (Stewart et al, 2001) and stress-induced signalling compounds such as jasmonic acid (Constabel and Ryan, 1998;Gowda and Paul, 2002). The manner of induction and activation of latent PPO comprise: (i) activating the PPO genes, enhancing expression or de novo synthesis and (ii) changing original PPO activity through the activation of latent PPO enzyme.…”

Section: Ppo Activation In Red Clovermentioning

confidence: 99%

Red clover polyphenol oxidase and lipid metabolism

Ranst

Lee

Fievez

2011

Animal

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Increasing the polyunsaturated fatty acid (PUFA) composition of milk is acknowledged to be of benefit to consumer health. Despite the high PUFA content of forages, milk fat contains only about 3% of PUFA and only about 0.5% of n-3 fatty acids. This is mainly due to intensive lipid metabolism in the rumen (lipolysis and biohydrogenation) and during conservation (lipolysis and oxidation) such as drying (hay) and ensiling (silage). In red clover, polyphenol oxidase (PPO) has been suggested to protect lipids against degradation, both in the silage as well as in the rumen, leading to a higher output of PUFA in ruminant products (meat and milk). PPO mediates the oxidation of phenols and diphenols to quinones, which will readily react with nucleophilic binding sites. Such binding sites can be found on proteins, resulting in the formation of protein-bound phenols. This review summarizes the different methods that have been used to assess PPO activity in red clover, and an overview on the current understanding of PPO activity and activation in red clover. Knowledge on these aspects is of major importance to fully harness PPO's lipid-protecting role. Furthermore, we review the studies that evidence PPO-mediated lipid protection and discuss its possible importance in lab-scale silages and further in an in vitro rumen system. It is demonstrated that high (induction of) PPO activity can lead to lower lipolysis in the silage and lower biohydrogenation in the rumen. There are three hypotheses on its working mechanism: (i) protein-bound phenols could directly bind to enzymes (e.g. lipases) as such inhibiting them; (ii) binding of quinones in and between proteins embedded in a lipid membrane (e.g. in the chloroplast) could lead to encapsulation of the lipids; (iii) direct binding of quinones to nucleophilic sites in polar lipids also could lead to protection. There is no exclusive evidence on which mechanism is most important, although there are strong indications that only lipid encapsulation in protein-phenol complexes would lead to an effective protection of lipids against ruminal biohydrogenation. From several studies it has also become apparent that the degree of PPO activation could influence the mode and degree of protection. In conclusion, this review demonstrates that protein-bound phenols and encapsulation in protein-phenol complexes, induced by PPO-mediated diphenol oxidation, could be of interest when aiming to protect lipids against pre-ruminal and ruminal degradation.Keywords: red clover, polyphenol oxidase, lipid metabolism, rumen, silage ImplicationsPolyphenol oxidase (PPO) is an enzyme that has been found to be active in red clover. There is a whole range of recent studies exploring possibilities of using this enzyme to protect membrane lipids against degradation in the forage during storage and in the rumen of ruminants. Protection of lipids against degradation is of importance as it could help to improve the fatty acid profile of ruminant products, with respect to consumer health. This review aims to summarize...

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Section: Ppo Activation In Red Clovermentioning

confidence: 99%

Red clover polyphenol oxidase and lipid metabolism

Ranst

Lee

Fievez

2011

Animal

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“…The involvement of plant hormones in stressinduced antioxidant system has been reported (Ben-Amor et al 1999;Arora et al 2002). For example, stimulation of ethylene synthesis is known to involve the generation of ROS (Steinite et al 2004;Ke and Sun 2004). Thus, the deleterious effects of ethylene have been linked with ROS detoxifying enzymes.…”

Section: Introductionmentioning

confidence: 99%

Effects of 1-MCP and exogenous ethylene on fruit ripening and antioxidants in stored mango

Wang

Feng

et al. 2008

Plant Growth Regul

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Mango (Mangifera indica L. cv. Tainong) fruits were harvested at the green-mature stage in Hainan and air-freighted to the laboratory at Peking. The fruits were treated with either 1 ll l -1 1-MCP or 5 ll l -1 ethylene for 24 h and stored at 20°C for up to 16 days. 1-MCP maintained fruit firmness, whereas exogenous ethylene decreased fruit firmness. Exogenous ethylene accelerated the increase in ethylene and 1-aminocyclopropane-1-carboxylate (ACC) oxidase, whereas 1-MCP reduced both. Exogenous ethylene stimulated and 1-MCP inhibited the production of H 2 O 2 of mango fruit during storage. Ascorbic acid was maintained at a high concentration in 1-MCPtreated fruit but was low in ethylene-treated fruit. 1-MCP inhibited activities of antioxidant enzymes including catalase, superoxide dismutase and ascorbate peroxidase. These results suggest that 1-MCP could play a positive role in regulating the activated oxygen metabolism balance.

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“…21 H 2 O 2 generated through NADPH oxidase and superoxide dismutase was shown necessarily for regurgitant-induced increase of ethylene production. 22 Taken together, we propose the existence of a regulatory mechanism between H 2 O 2 and ethylene to modulate cotton fiber and may be other related types of cell elongation (Fig. 2C).…”

mentioning

confidence: 99%