Related Enzyme Activities Research Articles

Physiological and Cellular Ultrastructural Responses of Isatis indigotica Fort. under Salt Stress

This study aimed to analyze the effects of salt stress on the growth physiology and plant-cell ultrastructure of Isatis indigotica Fort. (I. indigotica) to evaluate its adaptability under salt stress. The effects of different concentrations of salt (NaCl; 0, 25, and 300 mmol·L−1) on the agronomic traits, activities of related enzymes, ion balance, and mesophyll-cell ultrastructure of I. indigotica were studied in a controlled pot experiment. Results showed that compared with those of the control group, the aerial-part fresh weight, underground fresh weight, tiller number, root length, root diameter, plant height, and leaf area of salt-stressed I. indigotica increased at 25 mmol·L−1 and then decreased at 300 mmol·L−1. The changes in levels of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase showed a similar trend, with significant differences compared with control group. Salt stress altered the ion balance of I. indigotica, resulting in a significant increase in Na+ content and a significant decrease in K+ content. The contents of Ca2+ and Mg2+ changed to varying degrees. The analysis of the microstructure of the root showed that under salt treatment, the epidermal cells of the root significantly thickened and the diameter of the xylem decreased. The results of ultrastructural analysis of mesophylls showed that salt stress can cause cell-membrane contraction, cell-gap enlargement, disorder in the structures of chloroplasts and mitochondria, and an increase in the number of osmiophilic particles. These changes were aggravated by the increase in NaCl concentration. This study reveals the response of I. indigotica to salt stress and provides a basis for further study on the salt-tolerance mechanism of I. indigotica.

Carbon dioxide and weak magnetic field enhance iron-carbon micro-electrolysis combined autotrophic denitrification

Combining iron-carbon micro-electrolysis and autotrophic denitrification is promising for nitrate removal from wastewater. In this study, four continuous reactors were constructed using CO2 and weak magnetic field (WMF) to address challenges like iron passivation and pH stability. In the reactors with CO2 + WMF (10 and 35 mT), the increase in total nitrogen removal efficiency was significantly higher (96.2 ± 1.6 % and 94.1 ± 2.7 %, respectively) than that of the control (51.6 ± 2.7 %), and Fe3O4 converted to low-density FeO(OH) and FeCO3, preventing passivation film formation. The WMF application decreased the N2O emissions flux by 8.7 % and 20.5 %, respectively. With CO2 + WMF, the relative enzyme activity and abundance of denitrifying bacteria, especially unclassified_Rhodocyclaceae and Denitratisoma, increased. Thus, this study demonstrates that CO2 and WMF optimize the nitrate removal process, significantly enhancing removal efficiency, reducing greenhouse gas emissions, and improving process stability.

Nitrogen Addition Mitigates Drought by Promoting Soybean (Glycine Max (Linn.) Merr) Flowering and Podding and Affecting Related Enzyme Activities

Drought at the flower and pod stage, which is the most moisture-sensitive stage of soybean development, is the main cause of yield loss in soybean. Nitrogen is a vital nutrient for soybeans. The objective of this study was to assess the potential of post-drought nitrogen fertilization at the soybean (Heihe 45) pod stage to (1) reduce pod shedding and increase yield, and (2) elucidate the mechanisms by which nitrogen fertilization regulates soybean growth under drought stress. The pot experiment was designed with two moisture levels and three nitrogen levels, resulting in a total of six treatments. The results show that nitrogen reduces cellular oxidation by regulating key enzymes of sucrose metabolism, such as sucrose synthase and sucrose phosphate synthase; and regulates cellulase to reduce shedding and mitigate drought. Comparison of low and high nitrogen conditions under drought conditions showed that the number of flowers and pods in soybean increased by 30% and 32.94%, respectively, malondialdehyde content decreased by 24%, cellulase activity in flowers and pods decreased by 15.07% and 12.31%, respectively, and yields increased by 29.98% under high nitrogen conditions. The high nitrogen treatment performed optimally and the differences between treatments reached the significant level.

Effects of melatonin on inhibiting quality deterioration of postharvest water bamboo shoots

Water bamboo shoots (Zizania latifolia) is prone to quality deterioration during cold storage after harvest, which causes the decline of commodity value. Chlorophyll synthesis and lignin deposition are the major reasons for quality degradation. This paper studied the influence of exogenous melatonin (MT) on the cold storage quality of water bamboo shoots. MT treatment could delay the increase in skin browning, hardness and weight loss rate, inhibit chlorophyll synthesis and color change of water bamboo shoots, while maintain the content of total phenols and flavonoids, and inhibit lignin deposition by inhibiting the activity and gene expression of phenylpropanoid metabolism related enzymes as PAL, C4H, 4CL, CAD, and POD. The results indicate that exogenous MT treatment can effectively inhibit the quality degradation of cold stored water bamboo shoots.

The inhibitory impact of Schisandrin on inflammation and oxidative stress alleviates LPS-induced acute kidney injury.

Inflammation and oxidative stress (OS) are the major pathogenic characteristics of acute kidney injury (AKI). Studies have shown that Schisandrin (Sch) could regulate inflammatory disease. However, the function and mechanism of Sch in AKI progression are still unknown. Here, we investigated Sch's potential effects and mechanism on mice's renal damage and macrophages induced by lipopolysaccharide (LPS). Sch decreased LPS-induced inflammatory factor production while increasing the activity of related antioxidant enzymes in macrophages and mouse kidney tissues. Hematoxylin and eosin staining revealed that Sch may have the ability to profoundly inhibit inflammatory cell invasion and tissue damage caused by LPS in renal tissue. Furthermore, Western blot and immunohistochemical studies showed that Sch exerted its effects mainly through up-regulation of nuclear factor erythroid 2-related factor 2/heme oxygenase-1 and inhibition of Toll-like receptor 4‒mitogen-activated protein kinases/nuclear factor-kappa B pathways. Collectively, this study illustrates that Sch suppresses LPS-stimulated AKI by descending inflammation and OS, illuminating prospective AKI treatment options.

Enhancing docosahexaenoic acid production from Schizochytrium sp. by using waste Pichia pastoris as nitrogen source based on two-stage feeding control

To reduce the cost of docosahexaenoic acid (DHA) production from Schizochytrium sp., the waste Pichia pastoris was successfully used as an alternative nitrogen source to achieve high-density cultivation during the cell growth phase. However, due to the high oxygen consumption feature when implementing high-density cultivation, the control of both the nitrogen source and dissolved oxygen concentration (DO) at each sufficient level was impossible; thus, two realistic control strategies, including “DO sufficiency-nitrogen limitation” and “DO limitation-nitrogen sufficiency”, were proposed. When using the strategy of “DO sufficiency-nitrogen limitation”, the lowest maintenance coefficient of glucose (12.3 mg/g/h vs. 17.0 mg/g/h) and the highest activities of related enzymes in DHA biosynthetic routes were simultaneously obtained; thus, a maximum DHA concentration of 12.8 ± 1.2 g/L was achieved, which was 1.58-fold greater than that of the control group. Overall, two-stage feeding control for alternative nitrogen sources is an efficient strategy to industrial DHA fermentation.

Maize/soybean intercropping increases nutrient uptake, crop yield and modifies soil physio-chemical characteristics and enzymatic activities in the subtropical humid region based in Southwest China

Intercropping, a widely adopted agricultural practice worldwide, aims to increase crop yield, enhance plant nutrient uptake, and optimize the utilization of natural resources, contributing to sustainable farming practices on a global scale. However, the underlying changes in soil physio-chemical characteristics and enzymatic activities, which contribute to crop yield and nutrient uptake in the intercropping systems are largely unknown. Consequently, a two-year (2021–2022) field experiment was conducted on the maize/soybean intercropping practices with/without nitrogen (N) fertilization (i.e., N0; 0 N kg ha−1 and N1; 225 N kg ha−1 for maize and 100 N kg ha−1 for soybean ) to know whether such cropping system can improve the nutrients uptake and crop yields, soil physio-chemical characteristics, and soil enzymes, which ultimately results in enhanced crop yield. The results revealed that maize intercropping treatments (i.e., N0MI and N1MI) had higher crop yield, biomass dry matter, and 1000-grain weight of maize than mono-cropping treatments (i.e., N0MM, and N1MM). Nonetheless, these parameters were optimized in N1MI treatments in both years. For instance, N1MI produced the maximum grain yield (10,105 and 11,705 kg ha−1), biomass dry matter (13,893 and 14,093 kg ha−1), and 1000-grain weight (420 and 449 g) of maize in the year 2021 and 2022, respectively. Conversely, soybean intercropping treatments (i.e., N0SI and N1SI) reduced such yield parameters for soybean. Also, the land equivalent ratio (LER) and land equivalent ratio for N fertilization (LERN) values were always greater than 1, showing the intercropping system’s benefits in terms of yield and improved resource usage. Moreover, maize intercropping treatments (i.e., N0MI and N1MI) and soybean intercropping treatments (i.e., N0SI and N1SI) significantly (p < 0.05) enhanced the nutrient uptake (i.e., N, P, K, Ca, Fe, and Zn) of maize and soybean, however, these nutrients uptakes were more prominent in N1MI and N1SI treatments of maize and soybean, respectively in both years (2021 and 2022) compared with their mono-cropping treatments. Similarly, maize-soybean intercropping treatments (i.e., N0MSI and N1MSI) significantly (p < 0.05) improved the soil-based N, P, K, NH4, NO3, and soil organic matter, but, reduced the soil pH. Such maize-soybean intercropping treatments also improved the soil enzymatic activities such as protease (PT), sucrose (SC), acid phosphatase (AP), urease (UE), and catalase (CT) activities. This indicates that maize-soybean intercropping could potentially contribute to higher and better crop yield, enhanced plant nutrient uptake, improved soil nutrient pool, physio-chemical characteristics, and related soil enzymatic activities. Thus, preferring intercropping to mono-cropping could be a preferable choice for ecologically viable agricultural development.

Hydrogen sulfide alleviates the chilling-induced lignification in loquat fruit by regulating shikimate, phenylpropanoid and cell wall metabolisms

Lignification is a typical symptom of chilling injury (CI) in loquat fruit under chilling stress. This study investigated the impact of hydrogen sulfide (H2S) on endogenous H2S, shikimate, phenylpropanoid, and cell wall metabolisms of loquat fruit during refrigeration. The findings suggested that H2S treatment hindered the rise in the CI index and firmness while delaying the reduction in extractable juice, soluble sugar, and titratable acid content of loquat fruit. Besides, H2S treatment promoted the endogenous H2S content, which was correlated with the increase in activities of related H2S synthase enzymes. Furthermore, H2S suppressed enzymes involved in shikimate and phenylpropanoid metabolisms, thereby decreasing phenylalanine and lignin accumulation. Simultaneously, H2S treatment retarded the increases in insoluble pectin, hemicellulose, and cellulose by orchestrating cell wall-modifying enzymes. This work indicates that H2S treatment may alleviate chilling-induced lignification by inhibiting lignin accumulation and enhancing the depolymerization and solubilization of cell wall polysaccharides.

Chemical composition of Artemisia argyi essential oil and its antifungal activity against dermatophytes by inhibiting oxidative phosphorylation and causing oxidative damage

Ethnopharmacological relevanceDermatophytes are notorious pathogens capable of infecting various mammals skin, posing serious threats to human health and overall life quality worldwide. Artemisia argyi has been recorded and applied for over a thousand years to treat skin itching. Although it has the potential to be developed as a plant-based antifungal agent, it’s antifungal activity and action mechanism of active ingredients are still unclear. Aim of the studyThe aim of this study was to investigate the chemical composition, antifungal activity against skin fungi, and potential mechanisms of Artemisia argyi essential oil (AEO). Materials and methodsThe chemical composition of AEO was analyzed by gas chromatography-mass spectrometry (GC-MS) firstly. Flat growth restraint and double half dilution tests was performed to evaluate AEO antifungal activity against Microsporum gypseum, Trichophyton mentagrophytes, and Trichophyton rubrum. And then, the physiological mechanism of AEO inhibiting dermatophytes was systematically explored through scanning electron microscopy, relative conductivity, membrane leakage, ROS content, and antioxidant enzyme activity. Finally, the main pathways were screened through transcriptome sequencing, while the related genes expression levels and enzyme activity were validated. ResultsMonoterpenes and sesquiterpenoids were the most highly representative class of AEO. AEO had powerful antifungal activity against M. gypseum, T. mentagrophytes, and T. rubrum, with minimum inhibitory concentration (MIC) values of 0.6, 1.2, and 1.2 μL/mL, respectively. Moreover, AEO can also damage the cell membrane integrity of T. mentagrophytes, resulting in cellular extravasation of intracellular substances. Transcriptome analysis revealed that the main target of AEO is to inhibit electron transfer and oxidative phosphorylation during respiration, ultimately leading to obstruction of normal ATP synthesis and energy metabolism in mitochondria. And a large amount of ROS will generate due to the incompletely catalysis of oxygen under mitochondrial complexes. Coupled with the decrease of antioxidant enzyme (SOD, POD) activity, excessive accumulation of ROS will cause serious oxidative damage to cells and eventually exhibiting antifungal activity against dermatophytes. ConclusionsThe present study demonstrated that Artemisia argyi was a valuable source of active compounds with antifungal activity. These findings support AEO as a potential agent to inhibit dermatophytes and prevent related dermatophytoses.

Direct Z‐Scheme Xylan‐Based Carbon Dots@TiO2‐x Nanocomposites for Visible Light Driven Photocatalytic of Dye Degradation and Antibacterial

AbstractTiO2 photocatalysis has gained attention as a cost‐effective way of degrading contaminants. However, it relies on UV excitation and experiences rapid carrier recombination. To address these drawbacks, novel xylan‐based carbon dots@hydrogenated TiO2 (CDs@TiO2‐x) composited by direct Z‐scheme heterojunction is fabricated as a visible light‐driven photocatalytic material, which broadens the range of light absorption to visible light and suppresses the recombination of photogenerated carriers. The spindle‐shaped CDs@TiO2‐x has C/N/O/S groups, positive charges, and oxygen vacancies on its surface, and can degrade 89% of methylene blue and 87% of methyl orange within 90 min, and 99% of rhodamine B within 60 min in visible light. It also eradicates 99.9% of E. coli in 2 h and 97.1% of S. aureus in 2.5 h. These performances surpass CDs and TiO2‐x, and exhibit advantages in similar composite materials. The degradation pathways of dyes and the specific antibacterial processes induced by ROS are thoroughly investigated through LC‐MS testing and related enzyme activity assays. DFT calculations study the role of oxygen vacancies, heterojunction mechanism, and catalytic sites. This study has developed a novel nanocomposite with applications in both dye degradation and sterilization, offering insights for multifunctional materials based on photocatalysis and heterojunction.

Earthworms improve the rhizosphere micro-environment to mitigate the toxicity of microplastics to tomato (Solanum lycopersicum)

Microplastics (MPs) are widespread in agricultural soil, potentially threatening soil environmental quality and plant growth. However, toxicological research on MPs has mainly been limited to individual components (such as plants, microbes, and animals), without considering their interactions. Here, we examined earthworm-mediated effects on tomato growth and the rhizosphere micro-environment under MPs contamination. Earthworms (Eisenia fetida) mitigated the growth-inhibiting effect of MPs on tomato plant. Particularly, when exposed to environmentally relevant concentrations (ERC, 0.02% w/w) of MPs, the addition of earthworms significantly (p < 0.05) increased shoot and root dry weight by 12–13% and 13–14%, respectively. MPs significantly reduced (p < 0.05) soil ammonium (NH4+-N) (0.55–0.69 mg/kg), nitrate nitrogen (NO3−-N) (7.02–8.65 mg/kg) contents, and N cycle related enzyme activities (33.47–42.39 μg/h/g) by 37.7–50.9%, 22.6–37.2%, and 34.2–48.0%, respectively, while earthworms significantly enhanced (p < 0.05) inorganic N mineralization and bioavailability. Furthermore, earthworms increased bacterial network complexity, thereby enhancing the robustness of the bacterial system to resist soil MPs stress. Meanwhile, partial least squares modelling showed that earthworms significantly influenced (p < 0.01) soil nutrients, which in turn significantly affected (p < 0.01) plant growth. Therefore, the comprehensive consideration of soil ecological composition is important for assessing MPs ecological risk.

Storage Temperature Affects the Accumulation of Phenolics in Fresh-Cut Melon by Accelerating the Sucrose Decomposition

To accurately evaluate the role of storage temperature in improving the quality of fresh-cut fruits and vegetables, the effects of two storage temperatures (5 °C and 15 °C) on the phenylpropanoid pathway and sucrose metabolism in fresh-cut melon (cv. Yugu) cubes were determined. A higher temperature (15 °C) expedited sucrose decomposition in the melon cubes at the early stage of storage, resulting in higher levels of glucose and fructose. This effect was corroborated by increased activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase cleavage (SS-c), along with higher expressions of CmAI1/2, CmNI1/2, and CmSS1/2 in the melon cubes at 15 °C. Additionally, the higher activity and gene expression of hexokinase in melon cubes at 15 °C led to an increase in the utilization rate of sugars toward downstream metabolic pathways. Moreover, the melon cube storage at 15 °C elevated the activities and gene expressions of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and 4-coumaric acid: CoA ligase (4CL), thereby increasing the synthesis of phenolics. Sucrose showed a significant negative correlation with PAL, C4H, and 4CL, as well as with CmPAL5/7 and CmC4H1/3. However, hexokinase displayed a significant positive correlation with PAL, C4H, and 4CL, as well as with CmPAL1, CmPAL3-9, CmC4Hs, and Cm4CLs. These findings demonstrate that a higher-temperature storage of melon cubes can accelerate the phenylpropanoid pathway and sucrose metabolism by regulating the activity and gene expression of related enzymes, thereby inducing phenolic accumulation. These results also indicate that lower-temperature storage is not conducive to the conversion of sugars into phenolics in fresh-cut melon. Therefore, the temperature can be appropriately and briefly raised in the production and preservation process of fresh-cut melon to obtain higher levels of phenolics.

Evaluation of gases emission and enzyme dynamics in sheep manure compost occupying with peach shell biochar

The effect of peach shell biochar (PSB) amendment on sheep manure (SM) composting was investigated. Five different ratios of PSB were applied (0%, 2.5%, 5%, 7.5%, and 10% PSB), and named T1 to T5, and run 50 days of composting experiment. It was found that PSB (especially 7.5% and 10%) could improve the compost environment, regulate the activity of microorganisms and related enzymes, and promote the decomposition of compost. 7.5% and 10% PSB advanced the heap into the thermophilic stage and increased the maximum temperature, while also increasing the germination index by 1.40 and 1.39 times compared to control. Importantly, 10% PSB effectively retained more than 60% of carbon and 55% of nitrogen by inhibiting the excess release of NH3 and greenhouse gases. High proportion PSB amendment increased the activity of dehydrogenase and cellulase, but inhibited protease and urease. The correlation results indicated that PSB changed the key bacterial genus, and there was a stronger association with environmental factors at 7.5% and 10%. Therefore, 7.5% and 10% peach shell biochar can be used as appropriate proportions to improve composting conditions.

Immobilization of a novel d-allulose 3-epimerase from Bacillus cihuensis within metal-organic frameworks

As a functional low-calorie sugar, d-allulose demonstrates significant potential for applications in the food industry. Ketose 3-epimerases (KE) catalyzing the epimerization of d-fructose into d-allulose, play a critical role in the production of d-allulose. Majority of the reported KE exhibited maximum activity at high temperatures (60–70 °C) and pH (7.5–8.0) with metal ions (Mn2+ or Co2+), resulting in browning reaction and complex processes (adjusting pH of fructose solution, removing heavy metal ions, etc.) in allulose production. In this study, a novel d-allulose 3-epimerase from B. cihuensis (BcDAE) was identified and characterized. The BcDAE showed maximum activity at 40–50 °C and pH 7.0, alongside exhibiting board pH tolerance in weakly acidic environments. As a mesophilic enzyme, BcDAE could provide advantages by mitigating browning reactions of substrate and product, minimizing by-product formation, and reducing energy consumption during production. Robustness in acidic environments of BcDAE might renders the enzyme well-suited for fructose conversion without pH adjustments. Considering the poor thermostability and dependence on Mn2+ of BcDAE, the enzyme was captured in Mn-BTC MOF material using a straightforward co-precipitation method. The MOF-based enzyme was subsequently encapsulated to form micrometer-sized immobilized enzyme PDA@BcDAE@Mn-BTC using polydopamine as the cross-linker. Metal ions are not required in the reaction using the immobilized BcDAE. Significantly, after 10 repeated usage cycles, the immobilized BcDAE maintained a relative enzyme activity exceeding 70%, surpassing the performance of other reported immobilized DAE within MOF. Furthermore, comprehensive characterization of the immobilized BcDAE confirmed the success and feasibility of the immobilization strategy.

Effect of polyethoxylated flavonoids (PMFs)-loaded citral and chitosan composite coatings on citrus preservation: From the perspective of fruit resistance

Previous studies have shown that polymethoxylated flavonoids-loaded citral emulsion (PCT) can inhibit the growth and reproduction of Penicillium in citrus; however, PCT is difficult to apply to fruit preservation due to its high fluidity and volatility. Therefore, in this study, we combined PCT with chitosan (CS) to investigate the effect of a composite coating on citrus preservation. The results showed that compared to the control group, the CS-PCT group could effectively reduce the decay rate and maintain moisture availability, color difference, and hardness. Moreover, the contents of nonenzymatic antioxidants and volatile substances with antimicrobial activity were better preserved. In addition, the activities of related antioxidant enzymes were greater in the treatment group, and the expression of the corresponding enzyme-encoding genes was upregulated. Consequently, CS-PCT treatment could effectively maintain fruit quality and improve the resistance of citrus fruits during storage; moreover, it can be considered a nontoxic and efficient citrus preservative.

Transcriptome analysis reveals the mechanism of antifungal peptide epinecidin-1 against Botrytis cinerea by mitochondrial dysfunction and oxidative stress

The marine antifungal peptide epinecidin-1 (EPI) have been shown to inhibit Botrytis cinerea growth, while the molecular mechanism have not been explored based on omics technology. This study aimed to investigate the molecular mechanism of EPI against B. cinerea by transcriptome technology. Our findings indicated that a total of 1671 differentially expressed genes (DEGs) were detected in the mycelium of B. cinerea treated with 12.5 μmol/L EPI for 3 h, including 773 up-regulated genes and 898 down-regulated genes. Cluster analysis showed that DEGs (including steroid biosynthesis, (unsaturated) fatty acid biosynthesis) related to cell membrane metabolism were significantly down-regulated, and almost all DEGs involved in DNA replication were significantly inhibited. In addition, it also induced the activation of stress-related pathways, such as the antioxidant system, ATP-binding cassette transporter (ABC) and MAPK signaling pathways, and interfered with the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathways related to mitochondrial function. The decrease of mitochondrial related enzyme activities (succinate dehydrogenase, malate dehydrogenase and adenosine triphosphatase), the decrease of mitochondrial membrane potential and the increase content of hydrogen peroxide further confirmed that EPI treatment may lead to mitochondrial dysfunction and oxidative stress. Based on this, we speculated that EPI may impede the growth of B. cinerea through its influence on gene expression, and may lead to mitochondrial dysfunction and oxidative stress.

Simulated logistical transport effects on textural change of wax apple using different packaging types during storage time

The textural damage caused by logistics transport is a major problem during the post-harvest logistics and storage time of agricultural products. To address the issue, this study investigated the impact on the textural change of wax apple with different packaging types by conducting international safe transit association 6-amazon. com-sioc type A (ISTA 6 A) tests and measured the changes in related indicators over the eight-day storage time period at 15 ℃. The results demonstrated that compared to non-vibrated wax apple of the same packaging type, the damage index of the vibration-treated wax apple increased to 0.39 at the end of storage time. This led to more noticeable damage to fruit texture in the vibration-treated wax apple. With the same outer packaging type, different types of expanded polyethylene (EPE) cushioning materials presented varying degrees of textural damage following vibration treatment. The order was double-layer foam net (DL-FN, 0.23) < single-layer foam net (SL-FN, 0.38) < EPE liner (EPE-L, 0.50). The superior cushioning performance of DL-FN could distribute vibratory energy across the entire wax apple to reduce partial textural injury, but SL-FN provided weaker cushioning protection. Furthermore, it was more beneficial for the dissipation of respiratory heat to suppress the related cell-wall enzymes activities and prevented internal cottony softening of wax apple by maintaining an appropriate environment within the packaging, while EPE-L prevented respiratory heat dissipation and water diffusion. Using the same cushioning type, no significant difference was observed in the damage of fruit texture between the wax apple packaging by foam box (FB, 0.25) and corrugated box (CB, 0.23). The finding suggested that when the outer package had sufficient supporting performance, the cushioning type required not only adequate cushioning property, but also excellent vapor and gas permeability in order to facilitate respiratory heat diffusion and better protect the textural integrity of the wax apple in the process of logistics. This protection was crucial for the development of wax apple in e-commerce logistics.

A novel immobilized magnetic neutral protease used in extraction of protein from streptomycin residue: Preparation, characterization and application

Antibiotic residue is a hazardous waste which contains much protein; the extraction of protein from antibiotic residue using neutral protease is an effective utilization path of antibiotic residue. In this work, an immobilized magnetic neutral protease (IMNP) was successfully prepared by immobilizing free neutral protease on the surface of magnetic carrier, and characterized by a series of analysis methods (SEM, BET, FTIR, TGA, XRD, and VSM). IMNP can retain > 90 % enzyme activity of free neutral protease and extract ∼36 % protein from streptomycin residue within 4 h at the optimal extraction condition (water content in antibiotic residue = 97.5 %, IMNP loading = 5 %, pH = 7.0, and extraction temperature = 50 ℃). The loss of neutral protease from the surface of IMNP and the possible poisoning of IMNP caused by the toxic substances in the streptomycin residue significantly affected the relative enzyme activity of IMNP (29.4 % enzyme activity of IMNP lost after 6th use). IMNP showed better storage performance, pH and thermal tolerance performance than those of free neutral protease.

Dissecting the role of salicylic acid in mediating stress response in mungbean cultivars concurrently exposed to Macrophomina phaseolina infection and drought stress

The combined stress studies provide fundamental knowledge that could assist in producing multiple stress resilient crops. The fungal phytopathogen, Macrophomina phaseolina is a major limiting factor in the productivity of the crop, Vigna radiata (mungbean). This fungal species tends to flourish under hot and dry conditions. Therefore, in this study the salicylic acid (SA) mediated stress responses in contrasting mungbean cultivars (Shikha and RMG-975) exposed to combined M. phaseolina infection (F) and drought stress (D) have been elucidated. The combined stress was applied to ten days seedlings in three orders i.e. drought followed by fungal infection (DF), drought followed by fungal infection with extended water deficit (DFD) and fungal infection followed by drought stress (FD). The severity of infection was analyzed using ImageJ analysis. Besides, the concentration of SA has been correlated with the phenylpropanoid pathway products, expression of pathogenesis-related proteins (β-1,3-glucanase and chitinase) and the specific activity of certain related enzymes (phenylalanine ammonia lyase, lipoxygenase and glutathione-S-transferase). The data revealed that the cultivar RMG-975 was relatively more tolerant than Shikha under individual stresses. However, the former became more susceptible to the infection under DFD treatment while the latter showed tolerance. Otherwise, the crown rot severity was reduced in both the cultivars under other combined treatments. The stress response analysis suggested that enhanced chitinase expression is vital for tolerance against both, the pathogen and drought stress. Also, it was noted that plants treat each stress combination differently and the role of SA was more prominently visible under individual stress conditions.

Rheological properties of indica rice determined by starch structure related enzymatic activities during after-ripening

The processing quality of indica rice must undergo ripening after harvest to achieve stability and improvement. However, the mechanism underlying this process remains incompletely elucidated. Starch, the predominant component in indica rice, plays a crucial role in determining its properties. This study focused on analyzing the rheological properties and starch fine structure, as well as the related biosynthetic enzymes of indica rice during the after-ripening process. The results showed that after-ripened rice exhibited increased elastic modulus (G′) and viscous modulus (G″), accompanied by a decrease in the loss tangent (Tan δ), indicating an enhancement in viscoelasticity and the gel network structure. Moreover, the proportions of amylopectin super long chains (DP 37–60) decreased, while those of medium chains (DP 13–24 and DP 25–36) or short chains (DP 6–12) of amylopectin increased. Additionally, the activities of starch branching enzyme (SBE) and starch debranching enzyme (DBE) declined over the after-ripening period. Pearson correlation analysis revealed that the rheological properties of after-ripened rice were correlated with the chain length distribution (CLD) of starch, which, in turn, was associated with its related endogenous enzymes. These findings provied new insights into understanding the quality changes of after-ripened indica rice.