Soluble Enzyme Research Articles

Grain Weight and Taste Quality in Japonica Rice Are Regulated by Starch Synthesis and Grain Filling Under Nitrogen–Phosphorus Interactions

To reveal the regulatory effects of nitrogen and phosphorus interactions on grain-filling- and starch-synthesis-related enzymes, and grain weight of superior grains (SGs) and inferior grains (IGs) and taste quality, the japonica rice cultivar Shennong 265 was grown under field conditions with three nitrogen levels (210, 178.5, and 147 kg N ha−1; N3, N2, and N1) and two phosphorus levels (105 and 73.5 kg P ha−1; P2 and P1). At the N3 level, the yield of P1 was significantly lower (by 19.26%) compared to P2; at the N2 and N1 levels, P1 yielded higher than P2, peaking at N2P1. Spikelets per panicle showed P2 exceeding P1 at the same nitrogen level, with the highest for both SGs and IGs observed at N2P2, followed by N2P1. Reductions in nitrogen and phosphorus decreased the grain-filling rate but prolonged the duration for grain-filling. N2P1 maintained grain weight by extending the grain-filling duration across the early, middle, and late stages of IGs, and the middle and late stages of SGs. Increased nitrogen enhanced the activities of soluble starch synthase (SSS) and starch branching enzyme (SBE), whereas increased phosphorus inhibited these activities in SGs but enhanced them in IGs. Reduced nitrogen and phosphorus fertilizer diminished ADP glucose pyrophosphorylase (AGPP) and granule-bound starch synthase (GBSS) activities in SGs and IGs, inhibiting amylose accumulation while enhancing taste value. Compared with N3P2, the taste value of N2P1 increased significantly by 6.93%, attributed to a higher amylopectin/amylose ratio. N2P1 (178.5 kg N ha−1 and 73.5 kg P ha−1) optimized enzyme activity, starch composition, and grain filling, balancing both yield and taste, and thus demonstrated an effective fertilization strategy for stable rice production.

Fc-binding nanodisc restores antiviral efficacy of antibodies with reduced neutralizing effects against evolving SARS-CoV-2 variants

Passive antibody therapies, typically administered via parenteral routes, have played a crucial role in the initial response to the COVID-19 pandemic. However, the ongoing evolution of SARS-CoV-2 has revealed significant limitations of this approach, primarily due to mutational escape and the inadequate delivery of antibodies to the upper respiratory tract. To overcome these challenges, we propose a novel prophylactic strategy involving the intranasal delivery of an antibody in combination with an Fc-binding nanodisc. This nanodisc, engineered to specifically bind to the Fc regions of IgG antibodies, served two key functions: extending the antibody's half-life in the larynx and trachea, and enhancing its neutralization efficacy. Notably, Sotrovimab, an FDA-approved monoclonal antibody that has experienced a significant decline in neutralizing potency due to viral evolution, exhibited robust antiviral activity when complexed with the nanodisc against all tested Omicron variants. Furthermore, the Fc-binding nanodisc significantly boosted the antiviral efficacy of the soluble angiotensin-converting enzyme 2 (sACE2) Fc fusion protein, which possesses broad but modest antiviral activity. In ACE2 transgenic mice, the Fc-binding nanodisc protected better than sACE2-Fc alone with two more log reduction in lung viral titer. Therefore, the intranasal Fc-binding nanodisc offers a promising and powerful approach to counteract the diminished antiviral activity of neutralizing antibodies caused by mutational escape, effectively restoring antiviral efficacy against various evolving SARS-CoV-2 variants.

A New Multi-Active Heterogeneous Biocatalyst Prepared Through a Layer-by-Layer Co-Immobilization Strategy of Lipase and Laccase on Nanocellulose-Based Materials

Lipase from Pseudomonas fluorescens (PFL) and laccase from Trametes versicolor were co-immobilized onto nanocellulose (NC), using a layer-by-layer approach. Initially, PFL was adsorbed onto NC through ionic and hydrophobic interactions. To achieve higher PFL immobilization yield and activity, NC was functionalized with aldehyde groups through periodate oxidation (NCox) or glutaraldehyde activation (NC-GA). FTIR analysis confirmed these chemical modifications. Among the functionalized NCs, NCox showed the best capacity to retain higher amounts of PFL (maximum load: 20 mg/g), and this support was selected to proceed with the co-immobilization experiments. In this process, NCox-250-PFL (NCox activated with 250 µmol/g of aldehyde groups) was covered with polyethyleneimine (PEI), laccase was co-immobilized, and a crosslinking step using glutaraldehyde was used to covalently attach the enzymes to the support, producing the biocatalyst NCox-250-PFL-PEI-Lac-GA. Co-immobilized enzymes presented higher thermal stability (50 °C) than soluble enzymes; co-immobilized laccase retained 61.1% of its activity after 24 h, and PFL retained about 90% after 48 h of deactivation at 50 °C. In operational stability assays, the heterogeneous biocatalysts maintained more than 45% of their activity after five cycles of pNPB hydrolysis and ABTS oxidation. This co-immobilized biocatalyst, with its high stability and activity retention, is a promising multi-active heterogeneous biocatalyst for use in cascade reactions of industrial interest.

Optimizing Thermal Stability: Evaluating the Impact of Heterofunctional Hydrophobic Supports on Immobilized Flaxseed Lipase.

Lipases have catalytic capacity in various processes such as hydrolysis. Those derived from plant sources, such as linseed, offer an economical alternative. The immobilization process facilitates the recovery and reuse of lipase, providing advantages such as resistance to high temperatures and difficulties in recovering and reusing free lipases, which makes product separation difficult. This study presents the immobilization of lipases extracted from flax seeds on octylfunctional hydrophobic supports. Additionally, the thermal stability of the derived products was evaluated in comparison with freely soluble lipase. The lipase exhibited a strong affinity for the evaluated heterofunctional hydrophobic supports, with DVS-activated octylagarose emerging as the most efficient method for immobilization, thus increasing catalytic activity upon resuspension. Furthermore, the octylagarose derivative demonstrated a notable increase in thermal stability. The main results of the study include that the soluble enzyme showed greater activity after 24 h, regardless of the temperature evaluated. The benzamide extract showed greater thermal stability, and all supports evaluated showed greater activity than the soluble enzyme after immobilization. Notably, lipase immobilized on octyl glyoxyl agarose showed the highest activity, demonstrated stability for 840 h at 60 °C, and had a half-life of 1242 h. Furthermore, the lipase immobilized in octyl glyoxyl agarose showed a stabilization factor approximately nine times greater than the free enzyme. These results suggest that immobilization, probably achieved through interfacial activation and multipoint covalent bonds, prevented the release of the enzyme into the medium with increasing temperature. This study thus highlights the significant potential of immobilizing flaxseed-derived lipase.

Antioxidant Responses in Chromium-Stressed Maize as Influenced by Foliar and Root Applications of Fulvic Acid

Maize (Zea mays L.) faces significant challenges to its growth and productivity from heavy metal stress, particularly Chromium (Cr) stress, which induces reactive oxygen species (ROS) generation and damages photosynthetic tissues. This study aimed to investigate the effects of fulvic acid (FA) application, via foliar spray or root irrigation, on mitigating chromium stress in maize by evaluating its impact on antioxidant activity and growth parameters. Two maize varieties, P3939 and 30Y87, were subjected to chromium stress (CrCl3·6H2O) at concentrations of 300 µM and 100 µM for a duration of 5 weeks. The experiment was conducted in a wire house under natural environmental conditions at the Seed Centre, Institute of Botany, University of the Punjab, Lahore, Pakistan. Physiological assessments included electrolyte leakage, chlorophyll pigment content, malondialdehyde (MDA) levels, and activities of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX) in maize leaves. Growth parameters were also monitored. The results revealed that chromium stress significantly reduced chlorophyll content and increased oxidative stress, as evidenced by elevated MDA levels and electrolyte leakage. However, FA application notably mitigated these effects: chlorophyll content improved by 15%, and MDA levels decreased significantly. Irrigation with FA was particularly effective, reducing MDA levels by 40% compared to the 300 µM chromium treatment. Furthermore, while chromium stress enhanced antioxidant enzyme activities, FA application further boosted total soluble protein levels and antioxidant enzyme activities under stress conditions. In conclusion, FA application demonstrates potential in improving maize tolerance to heavy metal stress by enhancing the antioxidant defense system and preserving photosynthetic pigments. These findings highlight FA’s promise as a practical strategy for mitigating the negative impacts of chromium stress on maize, promoting sustainable agricultural practices in contaminated environments.

Agar-Agar Matrix-Mediated Immobilization for Enhanced Catalytic Behavior and Stability of 1,4-α-D-Glucan Glucanohydrolase Obtained from Halotolerant Micrococcus spp. K11

Background:: Entrapment is supposed to be the most effective and simple method among various strategies of enzyme immobilization as it preserves the original conformation and biological activity of the enzyme with greater immobilization yield. A suitable and cost-effective protocol for the entrapment of 1,4-α-D-glucan glucanohydrolase obtained from halotolerant Micrococcus spp., K11 has been developed. Objective:: The major objective of the present study was to explore halotolerant bacteria as potential producer of 1, 4-α-D-glucan glucanohydrolase from salt mines. Method:: A total of 11 bacterial strains were isolated and purified using the halophilic medium. Strain K11 was selected on the basis of a large zone of starch hydrolysis. The crude enzyme extract was utilized to entrap in agar-agar scaffolds. Kinetic studies of agar-agar entrapped 1,4-α-Dglucan glucanohydrolase were assessed and compared with the properties of soluble enzyme. Results:: It was observed that optimum immobilization of 1,4-α-D-glucan glucanohydrolase was attained at 4% concentration of agar-agar. Maximum entrapped enzyme activity was noticed after 15 minutes, highlighting the 5-minute increase in free enzyme. Moreover, temperature maxima for optimal enzyme substrate reaction were recorded to be 30°C for both immobilized and soluble 1,4-α-D-glucan glucanohydrolase, whereas pH maxima of 1,4-α-D-glucan glucanohydrolase were shifted from 6.5 to 7.0 after entrapment. The need for optimum substrate concentration for entrapped amylase activity was recorded to be 3% (gm), and for soluble 1,4-α-D-glucan glucanohydrolase, 2% (gm) starch was required for improved enzymatic efficacy. The reusability studies showed that agar-agar immobilized 1,4-α-D-glucan glucanohydrolase could be consumed up to 6 repeated cycles. Conclusion:: It is concluded that exploited features of immobilized 1,4-α-D-glucan glucanohydrolase enhance its applicability in several industrial processes.

Innovative engineering of superoxide dismutase for enhanced cardioprotective biocatalysis in myocardial ischemia-reperfusion injury

The present research compares the stability, catalytic activity, and cardioprotective benefits of the designed superoxide dismutase (SOD) variation SOD-M3 to those of the naturally occurring enzyme, along with additional alternatives. SOD-M3 exhibited a 51.5% increase in expression yield, reaching 50mg/L, compared to the wild-type's 33mg/L. In structural biology, the average distance between atoms of stacked proteins or molecules is measured by RMSD. Testing the precision of protein-ligand docking models is a typical application. The projected structure closely resembles the reference or native structure when the RMSD is low. The enzyme's durability improved significantly, resulting in negligible aggregation in the Size Exclusion Chromatography (SEC) and root mean square deviation (RMSD) of 2.1Å. SOD-M3 catalytically increased superoxide radical scavenging capability by 40% and inhibited nitroblue tetrazolium (NBT) reduction by 90% at 1μg/mL concentration. The material exhibited increased stability, as seen by its decomposition temperature (Tm) of about 80°C, as opposed to 65°C in the wild-type strains. In cardiomyocyte protection experiments, SOD-M3 reduced lactate dehydrogenase (LDH) production by 55% while decreasing reactive oxygen species (ROS) concentrations by 60%. Since a 51.5% increase in expression yield for SOD-M3 indicates improved production efficiency, which makes large-scale manufacturing more viable for clinical applications, it is therapeutically essential. Higher expression yields mean more cost-effective manufacture for enzyme-based therapy research and commercialization. In vivo, SOD-M3 decreased myocardial infarction diameter by 44% while improving cardiac function, including increased ejection percentage and fractional contraction. The histopathological investigation revealed undamaged heart tissue and less necrotic areas. The results reported here demonstrate SOD-M3's superior activity of enzymes, cardioprotective perspective, and stability, making it a promising therapeutic alternative for illnesses related to cellular oxidation & ischemic cardiac diseases. An increase in enzyme concentrations can enhance the obtaining of reactive oxygen species (ROS), which build up during ischaemia episodes; therefore, this increase is essential. Improving the enzyme's solubility and stability by site-directed modifications makes SOD-M3 more stable and effective in physiological circumstances where its activity is crucial for therapeutic efficacy maximization. A further benefit of increased expression yield is that it can lower manufacturing costs, which will help get SOD-M3 into clinical settings. These modifications raise SOD-M3's cardioprotective potential, making it a strong contender for novel therapies against cardiac ischemia-reperfusion impacts.

Intestinal flow and digestive parameters of Lutzomyia longipalpis larvae.

Lutzomyia longipalpis Lutz & Neiva, 1912 (Diptera, Psychodidae), is the primary vector of Leishmania infantum Nicole, 1908, the etiological agent of American visceral leishmaniasis. During their development, sandfly larvae pass through four instars, consuming soil particles enriched with microorganisms and decomposing organic material. In numerous insect species, the intestinal epithelium not only secretes digestive enzymes and absorbs digested nutrients but also carries out additional functions, such as regulating luminal pH and facilitating the absorption or secretion of ions and water. The transport of ions and water plays a crucial role in the establishment of a countercurrent flow responsible for recycling soluble digestive enzymes. This study aimed to explore specific aspects of digestion in L. longipalpis larvae that remain poorly understood. We measured the intestinal flow within the endoperitrophic space, which varied depending on the type of diet offered to the larvae, with an average total time of 191min. Additionally, we demonstrated the countercurrent flow in L. longipalpis larvae. Finally, we showed that the production of digestive enzymes can be modulated by nutrient availability, particularly by the amino acids in the larval diet. The higher the amino acids concentration, the higher the trypsin activity. On the other hand, the aminopeptidase activity was poorly influenced by the amino acids concentration.

Solubilization Inclusion Bodies from Synthetic Recombinant PGA Gene Expressed in E. coli BL21(DE3) by Denaturing and Non-denaturing Agents

Background: With the rise in green chemistry, the synthesis of antibiotic compounds through enzymatic processes is a preferred option. Penicillin-G acylase (PGA) is an important enzyme for producing important antibiotics, such as penicillin and its derivatives. Therefore, studies on PGA have been conducted worldwide. In the penicillin biosynthetic pathway, PGA catalyzes the conversion of penicillin G into 6-amino penicillanic acid (6-APA), a precursor for the enzymatic synthesis of penicillin derivatives. Unfortunately, bacteria naturally produce PGA in small quantities. Objective: One strategy for producing this enzyme in large quantities is DNA recombination, which is expressed in Escherichia coli. The formation of inclusion bodies (IBs) is a common obstacle to protein overexpression in Escherichia coli. In this study, we discuss IBs solubilization methods for recombinant PGA derived from E. coli (rPGAEc) expressed in E. coli BL21 (DE3). Recombinant E. coli BL21 (DE3) cells harboring rPGAEc were induced with IPTG for enzyme expression. Induction was performed at 16 °C for 4 h and 24 h. The PGA enzyme expressed in the IBs form was then incubated in two solutions containing 8 M urea and 0.2% sarcosine to obtain a soluble enzyme. Results: Based on protein analysis by SDS-PAGE, a solution containing 8 M urea solubilized PGA more abundantly than 0,2% sarcosine. Conclusion: The solubilization technique of PGA expressed by E. coli proposed in this study is an alternative solution that can be considered for this purpose.

Polyethylenimine-Assisted Aggregation of β-Galactosidase from Kluyveromyces lactis

Using PEI as an aggregating agent with β-galactosidase from Kluyveromyces lactis was investigated with no solid support. PEI, a cationic polymer initiated instant aggregation with the enzyme in solution. The factors affecting the aggregation such as PEI to enzyme ratio, glutar aldehyde for cross-linking and pH were investigated. Aggregation and sedimentation as well as the residual activity of aggregates were effectively dependent on the PEI to enzyme ratios. Easily precipitating aggregates at the ratio of 1/8, PEI enzyme aggregates were able to contain all enzyme in the complexation and displayed 60% of initial lactase activity. The PEI aggregation of enzyme led to enhancements in chemical and physical characteristics compered to free enzyme. The soluble enzyme showed a narrow optimum at about pH 7 while pH optimum of the aggregates extended one pH unit toward the alkaline range. Upon overnight incubation at 40 ºC, aggregated enzyme displayed 30% greater stability on average at all pHs tested. Although the free enzyme showed the highest activity at 40°C, it rapidly lost 50% of its activity at 50°C. In contrast, the aggregated enzyme retained full activity at 50°C and 70% activity at 65°C. With markedly enhanced thermal stability, the half-life of the aggregated enzyme increased from 76 hours to 254 hours at 40ºC. Overall, the simple and rapid aggregation of PEI with the enzyme led to instant and intense clustering, resulting in higher thermal and pH stabilities. This method may potentially offer efficient and cost-effective catalysis in lactase conversion processes.

LED light improves shoot multiplication, steviol glycosides and phenolic compounds biosynthesis in Stevia rebaudiana Bertoni in vitro culture

Light-emitting diode (LED) lamps are efficient elicitors of secondary metabolites. To investigate the influence of LED light on steviol glycosides (SGs) and phenolic compounds biosynthesis, stevia shoots were cultured under the following LED lights: white–WL, blue–B, red–R, 70% red and 30% blue–RB, 50% UV, 35% red and 15% blue–RBUV, 50% green, 35% red and 15% blue–RBG, 50% yellow, 35% red and 15% blue–RBY, 50% far-red, 35% red and 15% blue–RBFR and white fluorescent light (WFl, control). RBG light stimulated shoots’ biomass production. RBFR had a beneficial impact on stevioside biosynthesis (1.62 mg/g dry weight, DW), while RBUV favoured the production of rebaudioside A (3.15 mg/g DW). Neochlorogenic, chlorogenic, caffeic, 4-feruloylquinic, isochlorogenic A, rosmarinic acids and the flavonoid quercitrin were identified in the obtained material. A stimulatory effect of RBFR and RBUV on the biosynthesis of phenolic compounds was noted. LED light also influenced stomata appearance, stomata density, photosynthetic pigments, soluble sugar content and antioxidant enzyme activities in stevia shoots. This is the first report to provide evidence of the stimulating effect of LED light on biomass yield, SGs production and phenolic compounds in stevia shoot cultures.

Mechanism of induced soluble sugar accumulation and organic acid reduction in plum fruits by application of melatonin

Melatonin (MT) can improve plant resistance and fruit quality. The mechanism by which MT affects soluble sugar and organic acids accumulation in drupe fruits is not clear. In this study, 100 µmol/L MT was sprayed on the leaves of plum trees at the second stage of rapid fruit expansion (90 and 97 d after flowering), and the effects of MT on plum fruit quality and its effects on the soluble sugar-organic acid metabolism were investigated. At 28 d after MT treatment (at maturity), the longitudinal diameter, fruit weight, and vitamin C content of plum fruits were increased by 5.05%, 12.93%, and 56.09%, respectively, compared to the control. MT caused significant increase in the total soluble solids content and decreased the titratable acid content. MT increased the contents of total soluble sugar, sucrose, sorbitol, and citric acid after 21 and 28 days of treatment, while decreasing the contents of fructose, malic acid, quinic acid, and tartaric acid after 28 days of treatment. Additionally, MT increased the activities of sucrose synthase (catabolism direction), sucrose phosphate synthase, glucokinase, fructokinase, sorbitol oxidase, and NADP+-malic enzyme, and decreased the activities of soluble acid converting enzyme, cell wall insoluble converting enzyme, NAD+-sorbitol dehydrogenase, and NAD+-malic dehydrogenase after 21 or 28 days of treatment. Moreover, the differentially expressed genes (DEGs) after 21 and 28 days of treatment were accelerated starch and sucrose metabolism, galactose metabolism, fructose and mannose metabolism, as well as glycolysis, gluconeogenesis, and pentose phosphate metabolism pathways. In conclusion, exogenous MT increases soluble sugar content and decreases organic acid content in plum fruits by regulating various soluble sugar-organic acid metabolic pathways, thereby improving the fruit quality.

Biochemical properties of immobilized horseradish peroxidase on ceramic and its application in removal of azo dye

In the current work, electrostatic interactions were used to immobilize the horseradish peroxidase (HRP) onto five types of ceramic materials (C) with different concentrations of oxidized metals (C1–C5). The highest immobilization efficiency (70 and 77%) was detected at 6 mg C3 and 18 enzyme units. Scanning Electron Microscope (SEM), Energy Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) analysis of C3-HRP confirmed the immobilization of the enzyme. After ten reuses, the reusability analysis showed that (66%) of the C3-HRP enzyme activity was retained. For C3-HRP, the optimum pH and temperature of the soluble enzyme were shifted from 7.0 and 30 °C to 6.0 and 50 °C. Up to 40 °C and 50 °C, respectively, the soluble HRP and C3-HRP remained steady. The kinetic analysis revealed that the Km and Vmax of soluble HRP and C3-HRP were, respectively, 5.5 mM, 0.66 units, and 8 mM, 0.52 units for hydrogen peroxide (H2O2) and 35.5 mM, 3.4 units and 40 mM, 1.1 units for guaiacol. Compared to soluble-HRP, the C3-HRP exhibited a greater oxidizing affinity toward several phenolic compounds (Guaiacol, o-dianisidine, o–phenylenediamine, pyrogallol, p-aminoantipyrine). In comparison with soluble-HRP, the C3-HRP showed increased stress tolerance with Triton X-100, urea, metals, isopropanol, and dimethyl sulfoxide. The C3-HRP removed methyl orange more effectively compared to soluble-HRP.

Unveiling Salt Tolerance Mechanisms and Hub Genes in Alfalfa (Medicago sativa L.) Through Transcriptomic and WGCNA Analysis.

Alfalfa (Medicago sativa L.), an important forage crop with high nutritional value and good palatability, plays a vital role in the development of animal husbandry in China. In Northeast China, there are vast areas of saline-alkali land that remain undeveloped. Given that alfalfa is a highly adaptable forage crop, exploring its salt tolerance at the molecular transcriptional level and identifying salt-tolerant genes has great significance for breeding salt-resistant alfalfa varieties. This also provides valuable genetic resources for better utilization of saline-alkali land. In this study, we conducted two rounds of screening on 41 alfalfa varieties and identified WL168 as a salt-sensitive variety and Longmu801 as a salt-tolerant variety. After 7 days of 300 mM salt stress, both varieties showed a decreasing trend in plant height, fresh weight, and dry weight over time, but Longmu801 demonstrated better water retention ability compared to WL168. Chlorophyll content also declined, but chlorophyll a and total chlorophyll levels in Longmu801 were higher than in WL168. Hydrogen peroxide and malondialdehyde levels increased overall, but Longmu801 had significantly lower levels than WL168 under prolonged stress. Both varieties showed increasing trends in soluble sugars, proline, and antioxidant enzymes (SOD, POD, CAT), with Longmu801 significantly outperforming WL168. This suggests that the two varieties share similar growth and physiological response mechanisms, with their differences primarily arising from variations in indicator levels. In the above, comparisons between varieties were conducted based on the relative values of the indicators in relation to their controls. Transcriptomic analysis revealed that under salt stress, Longmu801 had 16,485 differentially expressed genes (DEGs) relative to its control, while WL168 had 18,726 DEGs compared to its control. Among these, 2164 DEGs shared the same expression trend, with GO functions enriched in response to oxidative stress, nucleus, plasma membrane, and others. The KEGG pathways were enriched in phenylpropanoid biosynthesis, protein processing in the endoplasmic reticulum, starch and sucrose metabolism, and others. This suggests that alfalfa's transcriptional response mechanism to salt stress involves these pathways. Additionally, the variety-specific DEGs were also enriched in the same KEGG pathways and GO functions, indicating that the differences between the two varieties stem from their unique stress-responsive DEGs, while their overall mechanisms for coping with stress remain similar. To further identify salt stress-related genes, this study conducted WGCNA analysis using 32,683 genes and physiological indicators. Six modules closely related to physiological traits were identified, and the top five genes ranked by degree in each module were selected as hub genes. Further analysis of these hub genes identified five genes directly related to salt stress: Msa085011, Msa0605650, Msa0397400, Msa1258740, and Msa0958830. Mantel test analysis revealed that these genes showed strong correlations with physiological indicators. This study will provide important insights for breeding salt-tolerant alfalfa varieties.

Promoting tomato resilience: effects of ascorbic acid and sulfur-treated biochar in saline and non-saline cultivation environments

The resilience of tomato plants under different cultivation environments, particularly saline and non-saline conditions, was investigated by applying various treatments, including 0.5% Ascorbic Acid (AsA) and 1% Sulphur-treated Biochar (BS). The study evaluated parameters such as fruit length, diameter, yield per plant and pot, Total Soluble Solids (TSS) content, chlorophyll content, electrolyte leakage, enzyme activities (Superoxide Dismutase - SOD, Peroxidase - POD, Catalase - CAT), and nutrient content (Nitrogen - N%, Phosphorus - P%, Potassium - K%). Under saline conditions, significant enhancements were observed in fruit characteristics and yield metrics with the application of AsA and BS individually, with the combined treatment yielding the most substantial improvements. Notably, AsA and BS treatments exhibited varying effects on TSS levels, chlorophyll content, electrolyte leakage, and enzyme activities, with the combination treatment consistently demonstrating superior outcomes. Additionally, nutrient content analysis revealed notable increases, particularly under non-saline conditions, with the combined treatment showcasing the most significant enhancements. Overall, the study underscores the potential of AsA and BS treatments in promoting tomato resilience, offering insights into their synergistic effects on multiple physiological and biochemical parameters crucial for plant growth and productivity.

Genome-wide identification of shaker K+ channel gene family in sugar beet (Beta vulgaris L.) and function of BvSKOR in response to salt and drought stresses

Genome-wide identification of shaker K+ channel gene family in sugar beet (Beta vulgaris L.) and function of BvSKOR in response to salt and drought stresses

Changes in Postharvest Quality and Physiological Attributes of Strawberry Fruits Influenced by l-Phenylalanine.

Strawberry (Fragaria × ananassa) is a popular fruit with rich nutrients and a delicious taste. But this fruit is very vulnerable to diseases and decay. Therefore, l-phenylalanine (Phe) (0, 4, 8 mM) was considered to improve biochemical characteristics and activity of antioxidant enzymes in strawberry fruit cv. Sabrina under cold storage (5, 10, 15 days). After treatment and storage, traits including weight loss, total phenol (TP), antioxidant capacity, ascorbic acid, total anthocyanin (TA), total flavonoid (TF), malondialdehyde (MDA), soluble protein content and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) and phenylalanine ammonialyase (PAL) were evaluated at 5-day intervals. Our findings showed that the treatment of l-phenylalanine in different concentrations prevented the weight loss of the fruit compared to the control and maintained and increased TP, antioxidant capacity, ascorbic acid, TA, TF, soluble protein and SOD, CAT, APX, POD, and PAL enzymes activity. Also, Phe decreased the MDA content and peroxidation of lipid. The results showed that 4 mM Phe is the best treatment for improving phytochemical characteristics and maintaining fruit quality. The findings indicated that Phe treatment may be useful to improve quality and increase postharvest shelf life in strawberry fruits.

Catalytic activities of tannase covalently linked to amino-functionalized carbon nanotubes

Immobilized Aspergillus ficuum tannase on amino-functionalized multiwalled carbon nanotubes (A-MWCNT) was assembled through glutaraldehyde-mediated covalent coupling to produce a stable biocatalyst nanocomposite. The effective binding of tannase on the surface of A-MWCNT was evaluated and authenticated by spectroscopic signature signals and morphological differences, before and after enzyme coupling. Both free- and immobilized tannase showed optimal catalytic activities at pH 5.0 and 35 °C, with the immobilized tannase exhibiting enhanced thermostability compared to the soluble enzyme. The immobilized tannase preparation was also found to be reusable up to five cycles, with 66% of initial enzyme activity retained thereafter. The enzyme-carbon nanotube composite preparation allows for bioconversion to be accomplished in a bioreactor with a smaller footprint.

Yield, cell structure and physiological and biochemical characteristics of rapeseed under waterlogging stress

Rapeseed (Brassica napus L.) is a major oilseed crop in the middle and lower reaches of the Yangtze River in China. However, it is susceptible to waterlogging stress. This study aimed to investigate the physiological characteristics, cellular changes, and gene expression patterns of rapeseed under waterlogging stress, with the goal of providing a foundation for breeding waterlogging-tolerant rapeseed. The results revealed that waterlogging-tolerant rapeseed exhibited higher levels of soluble sugars and antioxidant enzyme activity, particularly in the roots. Conversely, waterlogging-sensitive rapeseed displayed greater changes in malondialdehyde, proline, and hydrogen peroxide levels. Cellular observations showed that after experiencing waterlogging stress, the intercellular space of rapeseed leaf cells expanded, leading to disintegration of mitochondria and chloroplasts. Moreover, the area of the root xylem increased, the number of vessels grew, and there were signs of mitochondrial disintegration and vacuole shrinkage, with more pronounced changes observed in waterlogging-sensitive rapeseed. Furthermore, significant differences were found in the transcription levels of genes related to anaerobic respiration and flavonoid biosynthesis, and different varieties demonstrated varied responses to waterlogging stress. In conclusion, there are differences in the response of different varieties to waterlogging stress at the levels of morphology, physiological characteristics, cell structure, and gene transcription. Waterlogging-tolerant rapeseed responds to waterlogging stress by regulating its antioxidant defense system. This study provides valuable insights for the development of waterlogging-tolerant rapeseed varieties.

The energy metabolism of Cupriavidus necator in different trophic conditions.

The "knallgas" bacterium Cupriavidus necator is attracting interest due to its extremely versatile metabolism. C. necator can use hydrogen or formic acid as an energy source, fixes CO2 via the Calvin-Benson-Bassham (CBB) cycle, and grows on organic acids and sugars. Its tripartite genome is notable for its size and duplications of key genes (CBB cycle, hydrogenases, and nitrate reductases). Little is known about which of these isoenzymes and their cofactors are actually utilized for growth on different substrates. Here, we investigated the energy metabolism of C. necator H16 by growing a barcoded transposon knockout library on succinate, fructose, hydrogen (H2/CO2), and formic acid. The fitness contribution of each gene was determined from enrichment or depletion of the corresponding mutants. Fitness analysis revealed that (i) some, but not all, molybdenum cofactor biosynthesis genes were essential for growth on formate and nitrate respiration. (ii) Soluble formate dehydrogenase (FDH) was the dominant enzyme for formate oxidation, not membrane-bound FDH. (iii) For hydrogenases, both soluble and membrane-bound enzymes were utilized for lithoautotrophic growth. (iv) Of the six terminal respiratory complexes in C. necator H16, only some are utilized, and utilization depends on the energy source. (v) Deletion of hydrogenase-related genes boosted heterotrophic growth, and we show that the relief from associated protein cost is responsible for this phenomenon. This study evaluates the contribution of each of C. necator's genes to fitness in biotechnologically relevant growth regimes. Our results illustrate the genomic redundancy of this generalist bacterium and inspire future engineering strategies.IMPORTANCEThe soil bacterium Cupriavidus necator can grow on gas mixtures of CO2, H2, and O2. It also consumes formic acid as carbon and energy source and various other substrates. This metabolic flexibility comes at a price, for example, a comparatively large genome (6.6 Mb) and a significant background expression of lowly utilized genes. In this study, we mutated every non-essential gene in C. necator using barcoded transposons in order to determine their effect on fitness. We grew the mutant library in various trophic conditions including hydrogen and formate as the sole energy source. Fitness analysis revealed which of the various energy-generating iso-enzymes are actually utilized in which condition. For example, only a few of the six terminal respiratory complexes are used, and utilization depends on the substrate. We also show that the protein cost for the various lowly utilized enzymes represents a significant growth disadvantage in specific conditions, offering a route to rational engineering of the genome. All fitness data are available in an interactive app at https://m-jahn.shinyapps.io/ShinyLib/.