Search Results

Now showing 1 - 4 of 4

Some of the metrics are blocked by your
consent settings
Characterization of the Podospora anserina (Rabenh.) Niessl peroxidase gene family
(2024-02-15)
Ferrari, Roselyne
;
Gautier, Valérie
;
Tangthirasunun, Narumon
;
Chan Ho Tong, Laetitia
;
Silar, Philippe
Major role of peroxidases in plant biomass degradation is well-established in the white rot basidiomycetes. On the contrary, peroxidases are not used for this purpose by brown rot basidiomycetes, which use instead a non-enzymatic mechanism. In the case of the ascomycetes, not much is known although these fungi have peroxidase genes. Here, we identify and characterize the peroxidase genes of Podospora anserina (Rabenh.) Niessl, an ascomycete used to study development and lignocellulose degradation. We show that this fungus has one class II peroxidase, one hybrid B peroxidase, one haloperoxidase, four functional aromatic peroxygenases, one glutathione peroxidase, one cytochrome C peroxidase and one alkyl peroxidase, but lacks a dye peroxidase. We show that potentially secreted peroxidases (i.e., the class II, hybrid B, haloperoxidase and aromatic peroxygenase peroxidases) present a patchy phylogenetic distribution compatible with an accessory role in finely adapting the different fungal species to their ecological niche, rather than being involved in fundamental roles in fungal biology. Accordingly, targeted gene deletions of the different P. anserina peroxidase genes identified only one phenotype, seemingly an alteration of the timing of ascospore maturation at intermediate concentration of vanillic acid. However, direct measure of peroxidase activity did not show drastic loss of activity in the tested mutants, suggesting compensation between the enzymes. Hence, in P. anserina peroxidases appears to have a minor role in biomass degradation, unlike what has been described in white rot fungi, and thus in this regard appears to be similar to the brown rot fungi.
Some of the metrics are blocked by your
consent settings
Lotus flower extract as a natural anti-browning agent for fresh romaine lettuce (Lactuca sativa L. var. longifolia)
(2023-11-01)
Pradabkun, N.
;
Yeamsuriyotai, K.
;
Teerarak, M.
;
Saetiew, K.
The effect of lotus (Nelumbo nucifera Gaertn.), butterfly pea (Clitoria ternatea) and Siam tulip (Curcuma sessilis) aqueous extract on reduction of polyphenol oxidase (PPO) and peroxidase (POD) in romaine lettuce (Lactuca sativa L. var. longifolia) were evaluated. Results showed that in vitro lotus flower aqueous extract exerted the highest reduction of PPO and POD activities on the romaine lettuce. The effectiveness of in vivo application of lotus flower aqueous extract to control browning cut stem ends of fresh romaine was examined. Romaine lettuce harvested as a whole plant and cut off at the stem. Cut stem ends of romaine lettuce were dipped in various concentrations of lotus flower extract for 5 min and packaged in polypropylene plastic bags. Weight loss, color, browning index as well as PPO and POD activities were evaluated during 12 days of storage at temperature of 10±2°C and relative humidity 50±5%. Cut stem ends dipped in 0.5% aqueous extract of lotus flower resulted in inhibition of browning of cut stem ends and decrease in PPO and POD activities. Thus, exogenous 0.5% aqueous lotus flower extract treatment could be a useful application to alleviate browning in cut stem ends of fresh romaine lettuce.
Some of the metrics are blocked by your
consent settings
Changes in the activity of enzymes associated with enzymatic browning and chemical composition during Musa sapientum Linn. 'Kluai Khai' banana fruit ripening
(2023-07-01)
Makboriboon, N.
;
Teerarak, M.
;
Saetiew, K.
The results showed that the initial firmness of banana fruit harvested at the raw stage was 7 N and decreased to less than 2 N at overripe and very ripe stages. The total soluble solids increased throughout the ripening period, whereas the titratable acidity maintained a high level during the ripening process. The banana peel stayed green during the raw stage, and the yellow color formed between the unripe stage to the overripe stage. The lightness of the banana peel increased from the raw stage to the ripe stage, decreased at the overripe stage, and then dropped sharply at the very ripe stage. This color change was linked to the browning incidence of the fruit peel and an increasing browning area and soluble browning pigment content. The PPO and POD showed a low activity at the raw stage and then increased with advancing ripening and maintained a significantly higher level than the raw fruit. The findings of this study exhibited that the ripening stages of the 'Kluai Khai' banana influence the firmness, peel color, and browning incidence of the fruit peel and the polyphenol oxidase and peroxidase activities.
Some of the metrics are blocked by your
consent settings
Phenols and peroxidase activity in Pepper yellow leaf curl Thailand virus (PepYLCThV) resistant and susceptible chili (Capsicum annuum L.) genotypes
(2020-07-01)
Kingkampang, H.
;
Teerarak, M.
;
Kramchote, S.
;
Techawongstien, S.
;
Suwor, P.
Chilli (Capsicum annuum L.) is most commonly cultivated species. Pepper yellow leaf curl virus (PepYLCV) causes serious leaf curl disease of chili. In order to understand plant defence mechanism to PepYLCV disease, the study reported a response of total phenols and peroxidase activity in two contrasting pepper genotypes (resistant and susceptible) against PepYLCThV. The total phenolic content of uninoculated plants in susceptible genotype (KKUP31118) showed higher value than resistance genotype (9853-123) at both stages. However, the amount of total phenolic content in resistant genotypes was increased in juvenile and mature leaves in response to inoculation with PepYLCThV. In case of susceptible one, it was decreased as compared to uninoculated control. On the other hand, the peroxidase activity in chilli genotypes and at different stage of leaves was increased every week after inoculation and increased as a comparison to uninoculated plants. Hence, our finding suggested that the total phenols may act as defence mechanism in resistant genotype 9853-123.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results