473 Beneficial Effect of Heat-shock Treatments on Lettuce Applied before and after Wounding

Changes in phenolic metabolism are induced by minimally processing, which ultimately leads to the browning of lettuce tissue. Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5.) is greatly influenced by storage temperature. Evaluation of PAL activity at temperatures going from 0 to 25 °C showed that peaks occurred sooner at higher temperatures but at lower levels. Heat-shock treatments (50 °C, 90 s) have a protective effect against browning, help to retain greenness of tissue, and decrease the production of phenolics when applied either after or before wounding. To achieve a considerable, beneficial effect from hot water treatments applied after wounding these should not be delayed more than 36 h. The best results for heat-shock treatments before wounding occurred when applied at ≈12 h before cutting the tissue. Although cycloheximide did reduce PAL activity in a similar pattern as heat-shock treatments, it did not prevent browning itself. Cycloheximide seems to cause some sort of chemical damage that promotes the browning of lettuce tissue. When cycloheximide was applied in combination with heat-shock treatments browning did not occur.

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Acifluorfen Action on Growth and Phenolic Metabolism in Soybean (Glycine max) Seedlings

Weed Science ◽

10.1017/s0043174500072775 ◽

1989 ◽

Vol 37 (6) ◽

pp. 743-747 ◽

Cited By ~ 3

Author(s):

Robert E. Hoagland

Keyword(s):

Glycine Max ◽

Chlorophyll A ◽

Root Elongation ◽

Liquid Culture ◽

Phenylalanine Ammonia Lyase ◽

Hypocotyl Length ◽

Phenolic Metabolism ◽

Soybean Seedlings ◽

Pal Activity ◽

Chlorophyll Accumulation

Three-day-old soybean seedlings were treated with acifluorfen via liquid culture [50 μM in dark, 1 μM in light (200 μE·m–2·s–1)]. Root elongation in the dark was inhibited only slightly (6%) after 96 h. In the light, acifluorfen inhibited root elongation after 48 h; after 96 h, inhibition was 32%. Hypocotyl length was not affected in either the light or dark. Soluble hydroxyphenolic content per axis was unaffected in the dark but was reduced by about 13 to 25% at 24 to 96 h in the light. Extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity per axis was unaltered by herbicide in the dark. A brief transient increase in PAL activity (4 to 24 h) in axes of light-grown seedlings in the presence of acifluorfen was followed by reduced enzyme levels compared to light-grown controls at 72 and 96 h. Although light is required for maximal herbicide action, there was no effect on anthocyanin or chlorophyll accumulation or on the chlorophyll a/b ratio in hypocotyls or light-grown seedlings.

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Activity of phenylalanine ammonia-lyase, peroxidase and polyphenol oxidase in roots of banana (Musa acuminata AAA, cvs Grande Naine and Yangambi km5) before and after infection with Radopholus similis

Nematology ◽

10.1163/156854106777998674 ◽

2006 ◽

Vol 8 (2) ◽

pp. 201-209 ◽

Cited By ~ 10

Author(s):

Nathalie Wuyts ◽

Rony Swennen ◽

Dirk De Waele

Keyword(s):

Polyphenol Oxidase ◽

Phenylalanine Ammonia Lyase ◽

Phenylpropanoid Pathway ◽

Musa Acuminata ◽

Resistant Cultivar ◽

Radopholus Similis ◽

Wound Induction ◽

Pal Activity ◽

Before And After ◽

Burrowing Nematode

AbstractPhenylpropanoids – phenolic compounds – take part in the wound and defence responses of plants and are frequently correlated with resistance. Enzymes directly or indirectly functional in the phenylpropanoid pathway are induced in plants in response to wounding and infection by pathogens, including sedentary endoparasitic nematodes. The activity of three of these enzymes, phenylalanine ammonia-lyase (PAL), peroxidase (PO) and polyphenol oxidase (PPO), was analysed in banana roots before and 1, 3 and 7 days after inoculation with the burrowing nematode Radopholus similis and in comparison with mechanically wounded roots. Constitutive activities of PAL, PO and PPO were lower in the resistant cv. Yangambi km5 (Musa acuminata AAA) than in the susceptible cv. Grande Naine (Musa acuminata AAA). During the experiment, levels increased to those of cv. Grande Naine, but only for R. similis-inoculated roots of cv. Yangambi km5 enzyme activities at 3 and 7 days after the onset of the experiment were values significantly higher than constitutive ones. At 7 days after the treatments, PO activity was significantly higher in wounded roots of cv. Grande Naine than in control and nematode-inoculated roots. The level of PAL activity in nematode-treated roots of cv. Yangambi km5 at 7 days after inoculation was 2.3-fold higher than control and wounded roots and up to six-fold higher than cv. Grande Naine roots. We concluded that PAL was induced in R. similis-inoculated roots of the resistant cultivar only and that this response was different from wound induction. For PO and PPO we concluded that levels in the resistant cultivar increased to those of the susceptible cultivar as a response to general stress in the plants during the experiment. Nevertheless, final levels of PO and PPO activity in R. similis-inoculated roots of the resistant cultivar were significantly higher than constitutive ones.

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Effect of Intensity and Duration of Heat-shock Treatments on Wound-induced Phenolic Metabolism in Iceberg Lettuce

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.122.6.873 ◽

1997 ◽

Vol 122 (6) ◽

pp. 873-877 ◽

Cited By ~ 124

Author(s):

Julio G. Loaiza-Velarde ◽

Francisco A. Tomás-Barberá ◽

Mikal E. Saltveit

Keyword(s):

Phenolic Compounds ◽

Heat Shock ◽

Chlorogenic Acid ◽

Tartaric Acid ◽

Phenylpropanoid Metabolism ◽

Minimal Processing ◽

Subsequent Increase ◽

Phenolic Metabolism ◽

Pal Activity ◽

Iceberg Lettuce

Wounding during minimal processing of lettuce (Lactuca sativa, L.) induces alterations in phenolic metabolism that promote browning and the loss of quality. The activity of phenylalanine ammonia-lyase (PAL; the first committed enzyme in phenylpropanoid metabolism) and the concentration of phenolic compounds (e.g., chlorogenic acid, dicaffeoyl tartaric acid, and isochlorogenic acid) increase in excised iceberg lettuce midrib segments after wounding. The effect of short heat-shock treatments on browning and phenolic metabolism in excised midrib segments of iceberg lettuce was studied. As the heat-shock temperature increased from 20 to 70 °C, there was a decrease in the subsequent increase in PAL activity and the accumulation of phenolic compounds in excised midrib segments. Treatments of 45 °C for 120 s, 50 °C for 60 s, or 55 °C for 30 s significantly reduced the increase in PAL activity and subsequent browning seen in control tissue after wounding. Exposure to 45 °C for 480 s, 50 °C for 60 s, or 55 °C for 45 s prevented PAL activity from rising above initial levels. Phenolic compounds remained at initial levels for 3 days in excised midribs exposed to 50 °C for 90 s or to 55 °C for 60 s. However, 55 °C damaged the tissue, as indicated by a* and L* Hunter color values. The synthesis of chlorogenic acid, dicaffeoyl tartaric acid, and isochlorogenic acid was greatly reduced by these heat-shock treatments. These treatments also decreased polyphenol oxidase activity and, to a lesser extent, peroxidase activity.

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638 PB 366 EFFECTS OF PHENOLIC METABOLISM ON SUSCEPTIBILITY OF PEACH ROOTSTOCKS TO NEMATODES

HortScience ◽

10.21273/hortsci.29.5.524b ◽

1994 ◽

Vol 29 (5) ◽

pp. 524b-524

Author(s):

Yuan Yongbing ◽

A. M. Simeone ◽

P. Cappelini

Keyword(s):

Phenylalanine Ammonia Lyase ◽

Positive Relation ◽

Phenol Content ◽

Phenolic Metabolism ◽

Common Features ◽

Pal Activity ◽

One Year ◽

Peach Rootstocks ◽

And Control

Peach rootstocks Rancho Resistant (RR) and GF 677 are resistant and susceptible to nematodes, respectively. One-year-old seedlings of RR, GF677 and their reciprocal grafts were inoculated with 10,000 larvae. Both inoculated and control plants were harvested at intervals for assay. Phenylalanine ammonia lyase (PAL) activity and soluble phenol content were enhanced in both RR and GF677 after inoculation, but RR always had a 2-fold higher peroxidase (PO) activity than GF677. When GF677 was grafted on RR, the resistance of RR was not altered. When RR was grafted onto GF677, the number of galls on the plant were 66% and 77% less than on GF677 2 weeks and 2 months after inoculation, respectively. However, no interaction was found in the reciprocal graft. The results showed that higher soluble phenol content and PAL activity induced by nematode attack were common features of RR and GF677, and a positive relation between PO activity and resistance to nematode existed in the two rootstocks.

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Pretreatments at 38 °C of `Hass' Avocado Confer Thermotolerance to 50 °C Hot Water Treatments

HortScience ◽

10.21273/hortsci.32.4.705 ◽

1997 ◽

Vol 32 (4) ◽

pp. 705-708 ◽

Cited By ~ 19

Author(s):

Allan B. Woolf ◽

Michael Lay-Yee

Keyword(s):

Gene Expression ◽

Water Treatment ◽

Heat Shock ◽

Heat Shock Protein ◽

Persea Americana ◽

Hot Water ◽

Hot Water Treatment ◽

Avocado Fruit ◽

Hass Avocado ◽

Water Treatments

`Hass' avocados [Persea americana Mill.] were pretreated in water (38 °C for up to 120 min) immediately before 50 °C hot water treatments of up to 10 min. Fruit were stored for 1 week at 6 °C and ripened at 20 °C. External browning was evaluated immediately upon removal from cold storage, and fruit quality evaluated when fruit were ripe. Pretreatments at 38 °C tended to reduce the levels of external browning, skin hardening, and internal disorders, such as tissue breakdown and body rots, that were associated, and increased, with longer hot water treatments. A pretreatment of 60 min was the most effective for eliminating external browning, and reducing hardening of the skin when fruit were ripe following hot water treatment. Examination of heat shock protein (hsp) gene expression in avocado skin tissue, showed that levels of hspl7 and hsp70 homologous mRNA increased with increasing pretreatment duration. The results demonstrate that 38 °C pretreatments increase the tolerance of avocado fruit to subsequent hot water treatments.

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Wound-induced Phenolic Accumulation and Browning in Lettuce (Lactucasativa L.) Leaf Tissue is Reduced by Exposure to n-alcohols

HortScience ◽

10.21273/hortsci.40.4.1131b ◽

2005 ◽

Vol 40 (4) ◽

pp. 1131B-1131

Author(s):

Mikal Saltveit ◽

Youngjun Choi ◽

Francisco Tomás-Barberán

Keyword(s):

Phenylalanine Ammonia Lyase ◽

De Novo ◽

Physiological Responses ◽

Leaf Tissue ◽

De Novo Synthesis ◽

Phenolic Metabolism ◽

Pal Activity ◽

Wound Signal ◽

Fresh Cut ◽

Tissue Browning

A wound signal originates at the site of injury in lettuce [Lactucasativa (L.)] leaf tissue and propagates into adjacent tissue where it induces a number of physiological responses that include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subsequent tissue browning. Exposing excised mid-rib leaf tissue to vapors (20 μmol·g-1 FW) or aqueous solutions (100 mm) of n-alcohols inhibited this wound-induced tissue browning by 40% and 60%, respectively. Effectiveness of the alcohol increased linearly from ethanol to the seven-carbon heptanol, and then was lost for the longer n-alcohols 1-octanol and 1-nonanol. The 2- and 3-isomers of the effective alcohols did not significantly reduce wound-induced phenolic accumulation at optimal 1-alcohol concentrations, but significant reductions did occur at much higher concentrations (100 μmol·g-1 FW) of the 2-, and 3-isomers. The active n-alcohols were maximally effective when applied during the first 2 h after excision, and were ineffective if applied 12 h after excision. Phospholipase D (PLD) and its product phosphatidic acid (PA) are thought to initiate the oxylipin pathway that culminates in the production of jasmonic acid, and PLD is specifically inhibited by 1-butanol, but not by 2- or 3-butanol. These results suggest that PLD, PA, and the oxylipin pathway may be involved in producing the wound signal responsible for increased wound-induced PAL activity, phenolic accumulation, and browning in fresh-cut lettuce leaf tissue.

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Short-Time Treatment with Alkali and/or Hot Water To Remove Common Pathogenic and Spoilage Bacteria From Chicken Wing Skin

Journal of Food Protection ◽

10.4315/0362-028x-59.7.746 ◽

1996 ◽

Vol 59 (7) ◽

pp. 746-750 ◽

Cited By ~ 40

Author(s):

ANA MARIA RODRIGUEZ DE LEDESMA ◽

HANS P. RIEMANN ◽

THOMAS B. FARVER

Keyword(s):

Water Treatment ◽

Storage Temperature ◽

Bacterial Species ◽

Hot Water ◽

Control Group ◽

Hot Water Treatment ◽

Time Treatment ◽

Spoilage Bacteria ◽

Wing Skin ◽

Water Treatments

Dipping in 10% trisodium phosphate (TSP) at 10°C for 15 s and/or hot water (95°C) for 5 s significantly (P < 0,05) reduced the numbers of live Salmonella typhimurium, Listeria monocytogenes, and Staphylococcus aureus inoculated on the surface of chicken wings. Mean reductions after treatment with TSP (after storage at 10°C or 4°C, respectively) were 93.45% and 62.42% for S. typhimurium, 80.33% and 54.45% for S. aureus, and 39.04% and 81.41 % for L. monocytogenes. Similarly treatment with hot water resulted in reductions of 83.5% and 47.44%, 90.19% and 91.49%, and 68.57% and 77.83%, respectively, for the three bacterial species. The combined effects of TSP and hot water were 94.76% and 99.67%, 84.41 % and 96.68%, and 79.49% and 94.88%. After treatment with TSP, there was always a better recovery of L. monocytogenes when the wings were stored at 10°C compared to 4°C. No similar storage temperature effect on recovery of L. monocytogenes was observed in the absence of TSP. Based on the smell and appearance of uninoculated, fresh chicken wings after treatment with 10% solutions of TSP or Na2CO3 (10°C) and hot water, the control group was always preferred after 1 day of storage, but not after 6 days of storage. Combination treatment with TSP and hot water showed that after 7 days of storage the number of spoilage organisms was 3 log units higher on the control samples than on the treated wings. The combined TSP and hot water treatments were more effective in reducing counts of S. typhimurium, S. aureus, and L. monocytogenes than the combined Na2CO3 and hot water treatment (95°C for 5 s). Changes in subcutaneous temperature as a result of treatment with TSP and hot water treatment were minimal.

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Phenylalanine Ammonia-lyase Inhibitors Do Not Prevent Russet Spotting Lesion Development in Lettuce Midribs

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.123.4.687 ◽

1998 ◽

Vol 123 (4) ◽

pp. 687-691 ◽

Cited By ~ 12

Author(s):

Galen Peiser ◽

Gloria López-Gálvez ◽

Marita Cantwell ◽

Mikal E. Saltveit

Keyword(s):

Phenolic Compounds ◽

Phenylalanine Ammonia Lyase ◽

Phenylpropanoid Pathway ◽

Aminooxyacetic Acid ◽

Physiological Disorder ◽

Phenolic Metabolism ◽

Pal Activity ◽

Iceberg Lettuce ◽

Tartaric Acids ◽

Lyase Activity

Russet spotting is a physiological disorder of lettuce (Lactuca sativa L.) caused by exposure to hormonal levels (<1 μL·L-1) of ethylene in air at ≈5 °C. Enhanced phenolic metabolism and the accumulation of phenolic compounds accompany the appearance of brown, oval lesions on the leaf midrib. Phenylalanine ammonia-lyase (PAL) is the first committed enzyme in the phenylpropanoid pathway. Three inhibitors of PAL activity [2-aminoindan-2-phosphonic acid (AIP), α-aminooxyacetic acid (AOA), and α-aminooxi-β-phenylpropionic acid (AOPP)] greatly reduced the accumulation of phenolic compounds and browning of lesions. At a concentration of 50 μm, AIP inhibited the formation of chlorogenic and dicaffeoyl tartaric acids in cut midribs of iceberg lettuce by 92% and 98%, respectively. AIP competitively inhibited PAL activity from a lettuce midrib homogenate with an apparent Ki of 22 nm. While the formation of phenolic compounds was strongly inhibited by AIP, the number of lesions associated with russet spotting was not affected. Only the color of the lesions was affected by AIP. In control midribs the russet spotting lesions were brown while those in the AIP-treated midribs were initially olive green and after 3 to 7 days these lesions turned the characteristic brown color. No tyrosine ammonia-lyase activity was detected in a homogenate of lettuce midrib tissue. These results indicate that the early development of russet spotting lesions is independent of the increase in PAL activity and phenolic compounds rather than an effect of these increases as previously suggested. However, accumulation of phenolic compounds does contribute to the subsequent browning symptoms indicative of russet spotting.

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PHENOLIC METABOLISM AND INTERNAL BREAKDOWN (CHILLING INJURY) OF PEACH FRUIT

HortScience ◽

10.21273/hortsci.25.11.1356 ◽

1990 ◽

Vol 25 (11) ◽

pp. 1356H-1357 ◽

Cited By ~ 3

Author(s):

Hendrik van Gorsel ◽

Adel A. Kader

Keyword(s):

Phenolic Compounds ◽

Phenylalanine Ammonia Lyase ◽

Chilling Injury ◽

Limiting Factor ◽

Stone Fruits ◽

Peach Fruit ◽

Phenolic Metabolism ◽

Pal Activity ◽

Postharvest Handling ◽

Chilling Temperatures

Internal breakdown (IB) is the limiting factor in the storage and postharvest handling of stone fruits. The symptoms of IB appear when fruits are kept for prolonged periods at temperatures below 10C and include leatheriness, mealiness, browning and bleeding of the flesh, and failure to ripen normally. We investigated the changes in phenolic compounds associated with IB of stone fruits. Twenty-eight phenolic compounds were separated by HPLC. Ten of these components were significantly affected by chilling temperatures. The concentration of six phenols changed in response to ripening after chilling temperatures, parallel to the appearance of IB symptoms. Most phenols showed a concentration gradient from the inside to the outside of the fruit, Comparison between peach cultivars showed characteristic differences in phenol metabolism during ripening. In both cultivars the most predominant phenol, chlorogenic acid, showed little change in concentration during storage. The structure of key phenolic compounds will be determined in order to elucidate the biochemical relationship between the phenols and the related enzymes. In this respect, a method was developed to detect phenylalanine ammonia-lyase (PAL) activity in peach fruit.

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Surgery to relieve nasal obstruction: outcome for 366 patients operated on by one senior surgeon

European Archives of Oto-Rhino-Laryngology ◽

10.1007/s00405-021-06696-7 ◽

2021 ◽

Author(s):

Lars Aksel Pedersen ◽

S. Dölvik ◽

K. Holmberg ◽

C. Ahlström Emanuelsson ◽

H. Johansson ◽

...

Keyword(s):

Beneficial Effect ◽

Nasal Obstruction ◽

General Health ◽

Surgical Skills ◽

Nasal Endoscopy ◽

Experienced Surgeon ◽

Senior Surgeon ◽

Significant Difference ◽

Before And After ◽

The Mean

Abstract Background Studies of patient-rated outcome in septoplasty and turbinoplasty most frequently involve several surgeons with varying surgical skills, techniques and experience. The aim of the present study was to evaluate outcome based on one experienced surgeon. Methods Three hundred and sixty-six consecutive patients referred for nasal obstruction were included. All the patients were examined with nasal endoscopy before and after decongestion, they filled out a nose VAS and rated their overall general health before and three to six months after surgery. The patients underwent septoplasty, septoplasty plus turbinoplasty or turbinoplasty. Results The mean nose VAS for nasal obstruction (0–100) preoperatively was 64.7 for all patients. Patients undergoing septoplasty (n = 159) were younger than patients undergoing septoplasty + turbinoplasty (n = 79) or patients undergoing turbinoplasty alone (n = 128). The nose VAS for nasal obstruction improved significantly in all three groups and 25% had a normal nose VAS after surgery in the septoplasty and septoplasty + turbinoplasty groups compared to only 8% in the turbinoplasty alone group. There was no significant difference in the improvement in nasal obstruction between septoplasty and septoplasty + turbinoplasty, but the septoplasty + turbinoplasty group experienced a significantly greater improvement in general health. Conclusions In 366 patients operated on by one experienced surgeon, septoplasty and septoplasty + turbinoplasty were more effective at relieving nasal obstruction than turbinoplasty alone. Septoplasty + turbinoplasty resulted in a greater improvement in general health than septoplasty alone, despite the same improvement in nasal obstruction, indicating a beneficial effect of additional turbinoplasty in septoplasty.

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