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Antioxidants ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 115
Author(s):  
Songshen Hu ◽  
Tonglin Wang ◽  
Zhiyong Shao ◽  
Fanliang Meng ◽  
Hao Chen ◽  
...  

Tomato is susceptible to chilling injury during cold storage. In this study, we found that low temperature promoted the expression of brassinosteroid (BR) biosynthetic genes in tomato fruits. The overexpression of SlCYP90B3 (SlCYP90B3-OE), a key BR biosynthetic gene, alleviated the chilling injury with decreased electrical conductivity and malondialdehyde. In SlCYP90B3-OE tomato fruits, the activities of antioxidant enzymes, including ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), were markedly increased, while the activity of membranous lipolytic enzymes, lipoxygenase (LOX), and phospholipase D (PLD), were significantly decreased when compared with the wild-type in response to cold storage. Furthermore, the expression level of the cold-response-system component, SlCBF1, was higher in SlCYP90B3-OE fruits than in the wild-type fruits. These results indicated that SlCYP90B3 might be involved in the chilling tolerance of tomato fruits during cold storage, possibly by regulating the antioxidant enzyme system and SlCBF1 expression.


Author(s):  
Mengya Guo ◽  
Fengjuan Gu ◽  
Lingding Meng ◽  
Qiyong Liao ◽  
Zihui Meng ◽  
...  
Keyword(s):  

2022 ◽  
Vol 82 ◽  
Author(s):  
N. Hussain ◽  
A. Yasmeen ◽  
M. M. Yousaf ◽  
W. Malik ◽  
S. Naz ◽  
...  

Abstract Water stress is one of the major factor restricting the growth and development of chickpea plants by inducing various morphological and physiological changes. Therefore, the present research activity was designed to improve the chickpea productivity under water stress conditions by modulating antioxidant enzyme system. Experimental treatments comprised of two chickpea genotypes i.e. Bhakhar 2011 (drought tolerant) and DUSHT (drought sensitive), two water stress levels i.e. water stress at flowering stage and water stress at flowering + pod formation + grain filling stage including well watered (control) and three exogenous application of nutrients i.e. KCl 200 ppm, MgCl2, 50 ppm and CaCl2, 10 mM including distilled water (control). Results indicated that water stress at various growth stages adversely affects the growth, yield and quality attributes of both chickpea cultivars. Exogenous application of nutrients improved the growth, yield and antioxidant enzyme activities of both chickpea genotypes even under water stress conditions. However, superior results were obtained with foliar spray of potassium chloride on Bhakhar 2011 under well-watered conditions. Similarly, foliar spray of potassium chloride on chickpea cultivar Bhakhar 2011 cultivated under stress at flowering + pod formation + grain filling stage produced significantly higher contents of superoxide dismutase, peroxidase and catalase. These results suggests that the application of potassium chloride mitigates the adverse effects of water stress and enhanced tolerance in chickpea mainly due to higher antioxidant enzymes activity, demonstrating the protective measures of plant cells in stress conditions.


Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 7
Author(s):  
Ines Pottratz ◽  
Ines Müller ◽  
Christof Hamel

The production of prebiotics like galacto-oligosaccharides (GOS) on industrial scale is becoming more important due to increased demand. GOS are synthesized in batch reactors from bovine lactose using the cost intensive enzyme β-galactosidase (β-gal). Thus, the development of sustainable and more efficient production strategies, like enzyme immobilization in membrane reactors are a promising option. Activated methacrylatic monoliths were characterized as support for covalent immobilized β-gal to produce GOS. The macroporous monoliths act as immobilized pore-through-flow membrane reactors (PTFR) and reduce the influence of mass-transfer limitations by a dominating convective pore flow. Monolithic designs in the form of disks (0.34 mL) and for scale-up cylindric columns (1, 8 and 80 mL) in three different reactor operation configurations (semi-continuous, continuous and continuous with recirculation) were studied experimentally and compared to the free enzyme system. Kinetic data, immobilization efficiency, space-time-yield and long-term stability were determined for the immobilized enzyme. Furthermore, simulation studies were conducted to identify optimal operation conditions for further scale-up. Thus, the GOS yield could be increased by up to 60% in the immobilized PTFRs in semi-continuous operation compared to the free enzyme system. The enzyme activity and long-time stability was studied for more than nine months of intensive use.


2021 ◽  
Author(s):  
Susana Velasco ◽  
Javier Santiago-Arcos ◽  
Maria Grazia ◽  
Fernando López-Gallego

The activity orchestration of an unprecedented cell-free enzyme system with self-sufficient cofactor recycling enables the step-wise transformation of aliphatic diols into -hydroxy acids at the expense of molecular oxygen as electron acceptor. The efficiency of the biosynthetic route was maximized when two compatible alcohol dehydrogenases were selected as specialist biocatalysts for each one of the oxidative steps required for the oxidative lactonization of diols. The cell-free system reached up to 100% conversion using 100 mM of linear C5 diols, and performed the dessymetrization of prochiral branched diols into the corresponding -hydroxy acids with an exquisite enantioselectivity (ee > 99%). Green metrics demostrate a superior sustanability of this system compared to traditional metal catalysts and even to whole cells for the synthesis of 5-hydroxy petanoic acid. Finally, the cell-free system was assembled into a consortium of heterogeneous biocatalysts that allowed the enzyme reutilization. This cascade illustrates the potential of systems biocatalysis to access new heterofunctional molecules such as -hydroxy acids.


Author(s):  
Jonathan A. Clinger ◽  
Yinan Zhang ◽  
Yang Liu ◽  
Mitchell D. Miller ◽  
Ronnie E. Hall ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaiyuan Gu ◽  
Shuang Hou ◽  
Jinfen Chen ◽  
Jinge Guo ◽  
Fenfen Wang ◽  
...  

AbstractTobacco is be sensitively affected by chilling injury in the vigorous growth period, which can easily lead to tobacco leaf browning during flue-curing and quality loss, however, the physiological response of tobacco in the prosperous period under low temperature stress is unclear. The physiological response parameters of two tobacco varieties to low temperature stress were determined. The main results were as follows: ① For tobacco in the vigorous growing period subjected to low-temperature stress at 4–16 °C, the tissue structure of chloroplast changed and photosynthetic pigments significantly decreased compared with each control with the increase of intensity of low-temperature stress. ② For tobacco in the vigorous growing period at 10–16 °C, antioxidant capacity of the protective enzyme system, osmotic adjustment capacity of the osmotic adjusting system and polyphenol metabolism in plants gradually increased due to induction of low temperature with the increase of intensity of low-temperature stress. ③ Under low-temperature stress at 4 °C, the protective enzyme system, osmotic adjusting system and polyphenol metabolism of the plants played an insignificant role in stress tolerance, which cannot be constantly enhanced based on low-temperature resistance at 10 °C. This study confirmed that under the temperature stress of 10–16 °C, the self-regulation ability of tobacco will be enhanced with the deepening of low temperature stress, but there is a critical temperature between 4 and 10 °C. The self-regulation ability of plants under low temperature stress will be inhibited.


2021 ◽  
Author(s):  
◽  
Philip Geoffrey Charles Douch

<p>1. The metabolism of the N-methylcarbamates of 3-tertbutylphenol; 3,5-ditertbutylphenol; and 2-isopropoxyphenol was investigated in insects and mammals. 2. The major degradative pathway in enzyme systems from insects and mice was oxidative. The major metabolites from tertbutyl substituted phenyl-N-methylcarbamates were N-hydroxymethyl derivatives and tertbutanol derivatives. Baygon yielded N-hydroxymethyl, ring hydroxyl and O-dealkyl derivatives as major metabolites. 3. The rates of oxidation of the three insecticides in each enzyme system were similar. 4. Oxidation was inhibited by piperonyl butoxide and Metopirone, apparent I50 for singly oxidised metabolites was 10-4 M, and for metabolites with two oxidations 10-5M. 5. Enzymic hydrolysis of carbamate insecticides required reduced cofactor in insect and mouse systems. Mouse blood did not effect hydrolysis. 6. A wide variation of oxidising ability was found in live insects. Musca domestica was most active, Tenebrio molitor and Costelytra zealandica were least active. 7. Insecticide synergists reduce insects' ability to oxidise Baygon to acetone. 8. Musca domestica and Lucilia sericata larvae oxidised carbamate insecticides slower than the adult forms. 9. Mice excrete 3-tertbutylphenyl-N-methylcarbamate as phenolic metabolites, with only minor oxidative products. 10. Different rates of metabolism among insects could account for the selective toxicity of aryl-N-methylcarbamates.</p>


2021 ◽  
Author(s):  
◽  
Philip Geoffrey Charles Douch

<p>1. The metabolism of the N-methylcarbamates of 3-tertbutylphenol; 3,5-ditertbutylphenol; and 2-isopropoxyphenol was investigated in insects and mammals. 2. The major degradative pathway in enzyme systems from insects and mice was oxidative. The major metabolites from tertbutyl substituted phenyl-N-methylcarbamates were N-hydroxymethyl derivatives and tertbutanol derivatives. Baygon yielded N-hydroxymethyl, ring hydroxyl and O-dealkyl derivatives as major metabolites. 3. The rates of oxidation of the three insecticides in each enzyme system were similar. 4. Oxidation was inhibited by piperonyl butoxide and Metopirone, apparent I50 for singly oxidised metabolites was 10-4 M, and for metabolites with two oxidations 10-5M. 5. Enzymic hydrolysis of carbamate insecticides required reduced cofactor in insect and mouse systems. Mouse blood did not effect hydrolysis. 6. A wide variation of oxidising ability was found in live insects. Musca domestica was most active, Tenebrio molitor and Costelytra zealandica were least active. 7. Insecticide synergists reduce insects' ability to oxidise Baygon to acetone. 8. Musca domestica and Lucilia sericata larvae oxidised carbamate insecticides slower than the adult forms. 9. Mice excrete 3-tertbutylphenyl-N-methylcarbamate as phenolic metabolites, with only minor oxidative products. 10. Different rates of metabolism among insects could account for the selective toxicity of aryl-N-methylcarbamates.</p>


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