Changes In Lipoxygenase Activity Research Articles

Variations in 1-octen-3-ol and lipoxygenase gene expression in the oyster mushroom Pleurotus ostreatus according to fruiting body development, tissue specificity, maturity, and postharvest storage

Abstract 1-Octen-3-ol is considered a major contributor to the characteristic mushroom aroma. It has been proposed that in the oyster mushroom Pleurotus ostreatus, 1-octen-3-ol is synthesized through two pathways comprising either 13-hydroperoxy-9Z,11E-octadecadienoic acid (13-HPOD) or 10-hydroperoxy-8E,12Z-octadecadienoic acid as an intermediate, and that 13-HPOD is produced by the oxidation of linoleic acid by lipoxygenase (LOX). However, information on 1-octen-3-ol in this mushroom remains limited. This study investigated variations in 1-octen-3-ol and the LOX gene (Polox1 and Polox2) expression together with LOX activity in P. ostreatus, according to fruiting body development, tissue specificity, maturity, and postharvest storage. 1-Octen-3-ol content was abundant in the stipe of medium-sized fruiting bodies (40–50 mm cap diam), but decreased after 2 d of storage at 4 °C. During fruiting body development, changes in LOX activity mimicked changes in transcript levels of Polox1, which was much more abundantly expressed than Polox2. The changes in LOX activity were different from changes in 1-octen-3-ol levels according to fruiting body development, maturity, and postharvest storage. Our investigation suggests that medium-sized fruiting bodies that were not subjected to long-term storage would have a good aroma quality and that there is no correlation between 1-octen-3-ol synthesis and LOX activity, which is largely dependent on Polox1 expression.

Effects of heat and drought stress on post-illumination bursts of volatile organic compounds in isoprene-emitting and non-emitting poplar.

Over the last decades, post‐illumination bursts (PIBs) of isoprene, acetaldehyde and green leaf volatiles (GLVs) following rapid light‐to‐dark transitions have been reported for a variety of different plant species. However, the mechanisms triggering their release still remain unclear. Here we measured PIBs of isoprene‐emitting (IE) and isoprene non‐emitting (NE) grey poplar plants grown under different climate scenarios (ambient control and three scenarios with elevated CO2 concentrations: elevated control, periodic heat and temperature stress, chronic heat and temperature stress, followed by recovery periods). PIBs of isoprene were unaffected by elevated CO2 and heat and drought stress in IE, while they were absent in NE plants. On the other hand, PIBs of acetaldehyde and also GLVs were strongly reduced in stress‐affected plants of all genotypes. After recovery from stress, distinct differences in PIB emissions in both genotypes confirmed different precursor pools for acetaldehyde and GLV emissions. Changes in PIBs of GLVs, almost absent in stressed plants and enhanced after recovery, could be mainly attributed to changes in lipoxygenase activity. Our results indicate that acetaldehyde PIBs, which recovered only partly, derive from a new mechanism in which acetaldehyde is produced from methylerythritol phosphate pathway intermediates, driven by deoxyxylulose phosphate synthase activity.

Examination of the effects of temperature and pressure on lipoxygenase activities in pork using response surface methodology

To investigate the effects of pressure and temperature on lipoxygenase (LOX) in meat, changes in LOX activities in minced pork and in crude enzyme extracts under different conditions of pressure (131.82–468.18 MPa), temperature (23.18–56.82°C), and duration (6.59–23.41 min) were evaluated using response surface methodology. LOX activities in extracts exhibited a decrease with an increasing treatment temperature, pressure, or duration. Each of these factors alone had a significant (p<0.05) effect on LOX activities. Activation of LOX in most minced pork treated at less than 400 MPa was observed. Treatment pressure and temperature, and interactions between pressure and temperature and between duration and pressure, significantly (p<0.05) affected LOX activities. LOX showed higher stability in muscles than in extracts during combined pressure-heat treatments. The most important factor affecting LOX was treatment temperature for extracts and treatment pressure for muscles.

Effects of high pressure in combination with thermal treatment on lipid hydrolysis and oxidation in pork

For investigating the effects of high pressure in combination with thermal (HP-T) treatment on lipid hydrolysis and oxidation in pork, minced pork was treated with combinations of different pressures (200, 400, and 600 MPa) and temperatures (20 and 50 °C); the content and fatty acid profiles of intramuscular lipids, peroxide value (POV), thiobarbituric acid reactive substances (TBARS), and lipoxygenase (LOX) activity were measured. Treatment of samples at pressures of 400 MPa or above significantly enhanced the uneven hydrolysis of phospholipids, resulting in more polyunsaturated fatty acids (PUFA) in degraded phospholipids or generated free fatty acids (FFA); treatment temperature had a synergistic effect on phospholipid hydrolysis. Both POV and TBARS values increased with the intensity of treatment conditions until they reached the highest value, and then gradually decreased; neither corresponded closely with the changes in LOX activity. ANOVA-partial least squares regression (APLSR) analysis indicated that phospholipid hydrolysis positively correlated with TBARS but weakly correlated with POV. Thus, phospholipid hydrolysis could enhance lipid secondary oxidation, which mainly arising from auto-oxidation.

The effect of intercultivar substitution of wheat Triticum aestivum L. chromosomes on lipoxygenase activity and its correlation with the technological properties of flour

The effects of intercultivar substitution of individual chromosome pairs (except for 1B, 6D, and 7A) in the wheat cultivars Saratovskaya 29 and Janetzkis Probat, differing in quality, on specific lipoxygenase activity, the grain yield per spike, and the main technological properties of flour and dough were studied. It was demonstrated that the substitution of individual chromosomes of the recipient cultivar Saratovskaya 29 with the homologous chromosomes of the donor cultivar Janetzkis Probat caused significant changes in lipoxygenase activity and several other quality characteristics. The correlations between the lipoxygenase activity and the parameters of physical dough properties were determined. Three molecular forms of lipoxygenase (Lpx-1, Lpx-2, and Lpx-3), differing in the value of surface charge and enzymatic activity, were detected by native PAGE.

Changes in lipoxygenase properties and activity related to postgerminative growth and senescence in oat (Avena sativa L cv. Victory 1 )

Lipoxygenase (LOX), one of the main oxidative catalysts in plants, is involved in the regulation of growth and senescence. We investigated changes in LOX activity or its properties as they related to the development of oat plants at four stages (germination, growth, natural senescence, and dark-incubated senescence). LOX activity was high during early growth and at senescence. At pH 4.5, activity showed an abrupt surge compared with a normal enzyme reaction pattern at pH 6.5. The optimum reaction temperature was 25°C; LOX and peroxidase exhibited similar activity patterns. Polyacrylamide gel electrophoresis revealed that the purified LOX consisted of three isoenzymes in germinating seeds, two in growing seedlings, and three during both natural and dark-induced senescence. As determined by isoelectric focusing, the isoelectric points (pl) of LOX ranged from 3.6 to 6.5 throughout the four developmental stages; for natural or dark-induced senescence, the pl was 9.0.

Changes in flavor-affecting aroma compounds during potato storage are not associated with lipoxygenase activity

When potatoes are boiled and then chill-stored they rapidly develop off-flavor. This is a result of lipoxygenase activity, and is a serious problem in food-service systems. Lipoxygenase activity may vary during winter-storage of potatoes. Raw potatoes of the variety 'Bintje' were therefore analyzed for lipoxygenase activity during winter storage. Furthermore, content of potential off-flavors and typical potato aroma compounds were determined in raw, boiled, and in boiled/chill-stored potatoes. Four months after harvest the lipoxygenase activity started to increase, both when linoleic and linolenic acid were used as substrates. Production of typical oxidation products (aldehydes) of these fatty acids that earlier have been shown to cause off-flavor in boiled/chill-stored potatoes did, however, decrease. It is therefore concluded that this was not due to changes in lipoxygenase activity.

Changes in lipoxygenase activities in human erythroleukemia (HEL) cells during diosgenin-induced differentiation.

A human erythroleukemia (HEL) cell line was used as a model to study dynamic changes in human 12-, 15-, 5-lipoxygenases, five lipoxygenase activating protein (FLAP), and leukotriene A4 (LTA4) hydrolase gene expression during megakaryocytic differentiation induced by diosgenin (Beneytout, J.L., Nappez, C., Leboutet, M.J. and Malinvaud, G., Biochem. Biophys. Res. Commun., 207 (1995) 398-404). The study was performed at the transcriptional level: 12- and 5-lipoxygenase mRNAs, FLAP mRNA and LTA4 hydrolase mRNA were detected before and after diosgenin treatment in HEL cells while 15-lipoxygenase mRNA was undetected. When HEL cells were incubated with arachidonic acid, 5-, 12-, 15-hydroxyeicosatetraenoic acids (HETE) and LTC4 were synthesized. In contrast, the diosgenin treatment induced the suppression of 12-lipoxygenase activity and only 5-, 15-HETEs and LTC4 were synthesized.

Lipoxygense Activity and C6‐Aldehyde Formation in Comparison to Germination and Vigor during Soybean Seed Development

Developmental changes in lipoxygenase (LOX) activity have been observed during embryo maturation, which suggests that the LOX pathway may be involved in seed development. A study was designed to measure changes in LOX activity and C6‐aldehyde (hexanal and hexenal) formation during seed development and relate these changes to the attainment of maximum germination and vigor. Field grown soybean [Glycine max L. (Merr.) cv. Century] seeds were sampled at regular intervals starting at 31 d after flowering and continuing until maximum dry seed weight [physiological maturity (PM)] in 1990 and 1991. Axes and cotyledons from freshly harvested seeds were evaluated for LOX activity and C6‐aldehyde formation. The remaining seeds were air dried and tested for germination and vigor. Maximum germination occurred at 46 and 43 d after flowering in 1990 and 1991, respectively. Maximum vigor, as measured by accelerated aging, occurred at 54 and 48 d after flowering in 1990 and 1991, respectively, which was 18 d before PM. During seed development, maximum LOX activity occurred in both the axes and cotyledons during the linear phase of seed growth, but declined before PM. In the axes and cotyledons, maximum hexanal and trans‐2‐hexenal formation occurred at approximately 30% of final dry weight, which was before maximum LOX activity, except for axes in 1990. Maximum hexenal and hexenal formation coincided with the first maximum expression of germination, while maximum vigor was more closely related to maximum LOX activity in the axes (1991) and cotyledons. Maximum expression of seed quality (germination and vigor) and maximum LOX and C6‐aldehyde formation were correlated during soybean seed development.

Developmental changes in lipoxygenase activity in cotyledons of cucumber seedlings

Dry cucumber seeds have no lipoxygenase activity, but the activity in the cotyledons from light-grown seedlings increased rapidly from 3 days after germination, peaking at days 4–6 and declined significantly thereafter. The activity in the cotyledons from dark-grown seedlings increased in the same manner as observed in the light, but the enhanced activity persisted for a longer time. Transfer experiments showed that whether the cotyledons had been illuminated or not till day 6 lipoxygenase activity in the cotyledons degraded rapidly in the light concomitant with greening while it remained at the higher levels in the dark. Immunoblot analyses using antilipoxygenase serum indicate that the increase and decrease of lipoxygenase activity are mostly due to changes in the amount of lipoxygenase protein. The activity in the cotyledons from which the embryonic axis and the testa had been removed increased more rapidly than that in the cotyledons that had developed on the seedlings. Especially in the dark, lipoxygenase activity in the excised cotyledons increased by as much as 3.6-fold compared with the highest value observed with the intact cotyledons. Furthermore, detachment of the cotyledons from hypocotyl and roots at day 4 enhanced lipoxygenase activity. The enhancement was again marked in the dark.

Changes in lipoxygenase activity during seedling development of Lupinus albus

A lipoxygenase preparation was obtained from Lupinus albus seeds and was shown to differ from previously characterized lipoxygenase. This study describes changes in lipoxygenase activity during seedling development of Lupinus albus. The enzyme activity shows a decrease from 0–6 h postgermination (about 15%), is roughly constant or even rises slightly from 6–30 h and then shows a large increase between 30 and 48 h (about 50%). Enzymatically active proteins from 48 h-old seedlings were isolated and the increase of enzyme activity was mainly due to the presence of two components with maximum activity at pH 6 and pH 8.5, respectively. When arachidonic acid was used as substrate, the two enzymatic activities produce 15 HPETE. The increase in lipoxygenase activity during seedling development was inhibited by cycloheximide. Cordycepin appears to have no direct effect on lipoxygenase synthesis in vivo at the studied doses.

Changes in lipoxygenase activity in relation to lipid degradation in plucked tea shoots

The activity of lipoxygenase in tea leaf increased after plucking of tea shoots. The changes of lipoxygenase activity were accelerated by the dehydration of tea leaves. The activity of lipoxygenase was higher in the good fermenting clones than in the poor fermenting clones of black tea. The content of peroxide in tea shoots increased with rising lipoxygenase activity.