Non-enzymatic Systems Research Articles

Essential Oils from Citrus Peels Promote Calcium Overload-Induced Calcicoptosis in U251 Cells

Citrus peel essential oils (CPEOs) have demonstrated substantial medicinal potential for glioblastoma treatment because of their extensive antitumor effects, low potential for drug resistance, and ability to cross the human blood–brain barrier. In this study, the chemical compositions of five CPEOs were analyzed via gas chromatography–mass spectrometry (GC-MS). CCK8 assays were used to evaluate the ability of five CPEOs to inhibit U251 human glioblastoma cells, and XLB and RA were selected for further investigation. Through wound healing assays and cell cycle and apoptosis analyses via flow cytometry, it was revealed that these CPEOs inhibited cell migration, arrested the cell cycle at G1/G0, and induced apoptosis with similar levels of inhibition. After CPEOs treatment, the intracellular Ca2+ content and reactive oxygen species levels in U251 cells increased significantly, whereas the mitochondrial membrane potential decreased. Additionally, the antioxidant enzyme system (SOD, POD, CAT, and GR) and the nonenzymatic defense system (GSH) were inhibited, leading to an increase in lipid peroxidation. qRT–PCR indicated the significant upregulation of intracellular calcium ion signaling pathways and the upregulation of mitochondrial apoptosis-related genes. Additionally, the activation of calcicoptosis-related indicators induced by the CPEOs could be reversed by inhibitor treatment, confirming that both of the selected CPEOs inhibit tumors by activating calcicoptosis-related pathways. These findings highlight the immense potential of CPEOs in healthcare and pharmaceutical applications by not only providing a scientific basis for the potential application of CPEOs in the treatment of glioblastoma but also offering new insights for the development of novel antitumor drugs.

Antioxidant, Anti-Inflammatory, and Anticancer Activities of Five Citrus Peel Essential Oils.

Citrus peel essential oil (CPEO) is favored by people for its aromatic scent, while also possessing numerous bioactive compounds that are advantageous to human health. This study evaluated the antioxidant, anti-inflammatory, and anticancer activities of CPEOs through cell experiments. The results showed that CPEOs could increase the activity of the antioxidant enzyme system and nonenzymatic defence system in H2O2-treated RAW 264.7 cells by reducing cellular lipid peroxidation. CPEOs also reduced the nitric oxide production induced by lipopolysaccharide treatment in RAW 264.7 cells while decreasing proinflammatory cytokines expression and increasing anti-inflammatory cytokine expression. Wound healing assays, flow cytometry, and quantitative real-time fluorescent quantitative PCR (qRT-PCR) revealed that CPEOs could induce apoptosis in U87 cells through the mitochondrial apoptotic pathway. These findings indicate that CPEOs possess excellent antioxidant, anti-inflammatory, and anticancer activity potential, making them suitable for use in functional antioxidant and anti-inflammatory foods and nutritional health products.

Nitric oxide fumigation maintains cantaloupe fruit quality by regulating the production of reactive oxygen species

Cantaloupe (Cucumis melo L.) is a major crop cultivated in Northwest China. However, with the extension of storage periods, cantaloupes are increasingly prone to post-ripening senescence, quality deterioration, rot, and other phenomena, which in turn seriously limit shelf life. During postharvest storage, the quality of cantaloupes is affected by a large increase in ROS in the fruit. Herein, the effects of exogenous NO fumigation treatment on the quality of Xizhoumi NO.17 cantaloupe were investigated, with a focus on ROS generation and removal. NO fumigation treatment effectively reduced the rate of cantaloupe decay, inhibited fruit water loss and better maintained fruit firmness and relative conductivity. NO treatment induced O2·– and H2O2 production during early storage (within 24 h), whereas their accumulation decreased during later storage. NOX activity and expression of related genes in the treatment group were higher than those in the control group during the early storage but lower during later storage. NO fumigation also induced the antioxidant capacity of enzymatic and non-enzymatic systems in cantaloupe and helped to inhibit the accumulation of ROS. Taken together, NO fumigation triggers H2O2 production via the NOX/SOD system, activating the antioxidant response of cantaloupe to overcome excessive ROS production in the late stage of storage, thus maintaining fruit quality.

Electrochemical Properties of Copper Oxides Obtained from Layered Copper Hydroxide Acetate for Nonenzymatic Glucose Sensing

Nowadays, glucose sensing is a crucial role for capturing the status of diabetes, and its precise sensing directly contributes to prevent such diseases from exacerbating. While the use of enzymes such as glucose oxidase is known to be a major stream in glucose sensing. the issues of cost. Reusability. and chemical stability are still room for development. One of the non-enzyme system, copper oxides, would be a game-changer in place of enzymes.1 In addition to some great features which can address the aforementioned issues, copper oxides have a unique characteristic of their microstructure.1 Because the microstructure (surface area) greatly dictates the sensing ability, several literatures report the correlation between sensing ability and the microstructure of copper oxides. 2,3 With this keep in mind, we prepared several copper oxides with different morphology by using a one-pot fabrication process based on electrochemistry and investigate the effect of various morphologies of copper oxides on the glucose performance (Fig. 1A). We prepared copper oxides by reducing a layered copper hydroxide acetate (Cu2(OH)3Ac-) with various voltages.4 First, Cu(CH3COO)2・H2O was added into ultra-purified water and was allowed in a thermostatic bath at 60 ℃ for 30 h to obtain Cu2(OH)3Ac-.4 The resultant Cu2(OH)3Ac- was mixed with water and was drop casted onto a carbon paper. The obtained carbon paper incorporated with Cu2(OH)3Ac- was immersed in 0.1 M KHCO3 electrolyte and was exposed at the constant voltage of -1.2 V vs. Ag/AgCl for one hour to obtain copper oxide. (Figure. 1(A)) Figure 1(B) shows the cyclic voltammograms of carbon paper electrodes in the absence or presence of copper oxides in the electrolyte of 0.1 M NaOH with 5 mM glucose. For the carbon paper electrode, there is no oxidation current appeared in the voltage range of 0-0.8 V vs. Ag/AgCl, suggesting that the carbon paper itself is inert for electrochemical reactions in such voltage range. On the flipside, a significant oxidation peak appeared when the carbon paper incorporated with copper oxides was used. More importantly, the peak current has a strong relationship with glucose concentration (Figure 1(C)), suggesting the glucose concentration is electrochemically detectable. We will demonstrate and discuss the influence of the applied potential during the fabrication of copper oxides on the glucose response in the poster session.AcknowledgementsThe work was supported partly by Nippon Sheet Glass Foundation for Materials Science Engineering.References1) Y. Zhanga, N. Li, Y. Xiang, D. Wang, P. Zhanga, Y. Wang, S. Lu, R. Xu, J. Zhao, Carbon, 156, 506-513, (2020).2)P. D. Luna, R. Quintero-Bermudez, C. Dinh, M. B. Ross, O. S. Bushuyev, P. Todorović, T. Regier, S. O. Kelley, P. Yang, E. H. Sargent, Nat. Catal., 1(2), 103–110, (2018).3) A. R. Amirsoleimani, H. Siampour, S. Abbasian, G. B. Rad, A. Moshaii, Z. Zaradshan, Sens. Bio-Sens. Res., 42, 100589, (2023).4) S. Švarcová, M. Klementová, P. Bezdička, W. Łasocha, M. Dušek, D. Hradil, Cryst. Res. Technol., 46(10), 1051-1057, (2011). Figure 1

Exogenous application of melatonin and chitosan mitigate simulated microgravity stress in the Rocket (Eruca sativa L.) plant

Starting life in space and implementing spaceflight missions requires raising of plants in special conditions, where various stresses, including microgravity, are applied to plant. The use of stimulants is known as a promising effective approach that enhances plant resistance encountered a variety of abiotic stresses. In this study, the impact of two stimulants, melatonin and chitosan, in reducing negative effects of clinorotation on Rocket (Eruca sativa L.) seedlings was investigated from a physiological and biochemical point of view. For this purpose, a completely randomized experiment was designed where the treatments included control (without stimulants and normal gravity), melatonin (100 μM), chitosan (230 M), microgravity, microgravity + melatonin, and microgravity + chitosan. The results disclosed that the microgravity significantly impaired the plant growth and morphology, while exogenous application of melatonin and chitosan improved the plant growth parameters under stress conditions. Under microgravity, there was a reduction of 46.15% in shoot length (4.9 mm) and 41.44% in root length (4.7 mm) compared with the control (9.1 mm; 8.03 mm), respectively. Clinorotation led to a marked increment in the enzymes activity, wherein the POD, SOD and CAT activities increased by 75.13%, 72.67%, and 53.42%, respectively, compared with the control seedlings. In addition, supply of these two stimulants strengthened the scavenging of radial oxygen species and helped the plant to tolerate stress conditions, by activated the enzymatic and non-enzymatic systems. These results can pave the road for more studies and broad application of biological stimuli to overcome the space harsh environmental conditions by plants.

TwinDemic detection: A non-enzymatic signal amplification system for on-site detection of multiple respiratory viruses

The simultaneous occurrence of multiple respiratory viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 [CoV]) and influenza A virus (IAV), presents a challenge for accurate diagnosis and treatment. To address this, we developed the TwinDemic Detection (TDD) system—an integrated point-of-care diagnostic platform that can simultaneously detect CoV and IAV using a multi-respiratory virus identification approach. The TDD system contains a transparent poly(methyl methacrylate) microfluidic chip with a hydrogel-based gene detection sensor and a handheld fluorescence reader. This system uses a fuel-stimulated DNA probe to detect viral RNA and amplify the fluorescence signal without the need for enzymatic or thermal controls. The system’s performance was tested using 45 human nasopharyngeal samples; results revealed positive and negative predictive values of 93.3 % and 96.7 % for CoV, and 100 % and 96.7 % for IAV, respectively. This system enables the accurate and simultaneous detection of multiple respiratory viruses for public health surveillance and shows potential for use as a point-of-care molecular test to monitor a wider range of viruses in the future.

Fabrication and Potential Characterization of Silver‐Doped Zinc Oxide Glucose Biosensor

This work is devoted to studying and manufacturing a highly sensitive nonenzymatic glucose biosensing system of metal oxides via the sol–gel technique. The X‐ray diffraction patterns of all the prepared samples confirm that the samples present hexagonal crystal lattice structures of ZnO and Ag–ZnO nanoparticles. Ultraviolet (UV) analysis of all the samples is carried out to evaluate the absorption of silver in the UV region for electrical and chronoamperometric analysis. The transmittance of all the samples is observed, and the maximum transmittance is 11% for 4% AgZnO. Fourier transform infrared spectroscopy reveal the functional group stretching and vibration of the particles at different wavelength ranges. Scanning electron microsocpy analysis reveals the grain size and morphology of the samples, which decrease with increasing doping agent. Chronoamperometric analysis of all the samples reveals that the value increases with time for the 4% doped sample. The sensing response is also observed and is enhanced with increasing temperature for the 4% doped sample. The sensing response of the samples coated with carbon fiber electrodes is assessed from −0.2 to +0.5 V at a scan rate of 50 mV s−1.

The interaction effect of water deficit stress and seaweed extract on phytochemical characteristics and antioxidant activity of licorice (Glycyrrhiza glabra L.).

With increasing drought stress due to climate change and water scarcity, the agricultural sector has sought innovative strategies to mitigate the detrimental effects on crop productivity. One approach that has received significant attention is the use of fertilizers and biostimulants as potential means of alleviating drought stress. In this study, five different irrigation levels including 100% (control), 80% (slight stress), 60% (mild stress), 40% (moderate stress), and 20% (severe stress) of field capacity (FC) and seaweed extract (SWE) at three concentrations (0, 5, and 10 g/L) were applied to the pots containing one-year-old licorice (Glycyrrhiza glabra L.) plants in a factorial completely randomized design experiment with three replications for eight weeks. The glycyrrhizic acid content increased with water stress intensity without the application of SWE until severe (20% FC) water stress treatment. The application of 10 g/L SWE under 100% FC led to a significant increase in the glycyrrhizic acid value (32.5±0.889 mg/g DW) compared with non-SWE application (30.0±1.040 mg/g DW). The maximum glabridin content (0.270±0.010 mg/g DW) was obtained under irrigation of 20% field capacity with 10 g/L SWE application. In addition, the activity of the all studied enzymes such as APX (ascorbate peroxidase), CAT (catalase), POD (peroxidase), and SOD (superoxide dismutase) were boosted by increasing the water stress levels. The use of SWE further enhanced the increase of some of these metabolites and enzymes, which, in turn, helped the plant to tolerate stress conditions through the scavenging of more ROS (Reactive oxygen species), wherein for this purpose, the SWE 10 g/L was more effective than other concentration. The plants efficiently eliminated ROS driven from drought stress by both non-enzymatic and enzymatic systems.

Chronic Kidney Disease and Oxidative Stress

Abstract Disturbance of the balance between production of oxygen free radicals (or some other radical species) and activity of antioxidative system of protection causes the so called oxidative stress Protection of an organism from oxygen free radicals implies activity of enzymatic (catalase, SOD, glutathione peroxidase, glutathione reductase etc.) and nonenzymatic (vitamin E. vitamin C. glutathione, uric acid etc.) systems of protection. An organism can tolerate a mild oxidative stress but a higher disturbance between the production of free radicals and the activity of the antioxidative protection results in lipid protein and DNA as well as numerous diseases. In this article we analyze oxidative stress role as an important cofactor contributing to endothelial dysfunction, inflammation, atherosclerosis, glomerulosclerosis, anemia, tubulointerstitial nephritis and ischemia-reperfusion injury to chronic kidney disease patients.

Interface potential-induced natural antioxidant mimic system for the treatment of Alzheimer’s disease

Although the pathogenesis of Alzheimer’s disease (AD) is still unknown, the molecular pathological phenomena is clear, mainly due to mitochondrial dysfunction and central nervous system inflammation caused by imbalanced antioxidant capacity and synaptic dysfunction, so antioxidant therapy is still the preferred treatment for AD. However, although antioxidant enzymes have high catalytic efficiency, the substrate spectrum is narrow; Antioxidants have wider range of effects, but their efficiency is low. Since the antioxidant defense system in high-grade organisms is composed of both enzymatic and non-enzymatic systems, therefore we synthesized a metal-organic framework (MOF) with superoxide dismutase activity, and depending on the interface potential effect, curcumin was loaded to construct a synergistic antioxidant treatment system. More importantly, due to the complementary surface electrostatic potential between MOF and curcumin, the system exhibited both good antioxidant activity and efficient β-amyloid plaque scavenging ability, which slowed down the cognitive dysfunction in the brain of AD mice.

Responses of survival, antioxidant system and intestinal microbiota of native snail Bellamya purificata to the invasive snail Pomacea canaliculata

Pomacea canaliculata is one of the most successful invader in worldwide, adversely affecting native ecosystem through direct predation or indirect competition, while the mechanism of indirect effects on native species remain poorly understood. To clarify the effects of P. canaliculata on the native near-niche species, Bellamya purificata, a widespread freshwater gastropod in China, was selected as the research subject. The changes of mortality, histology, antioxidant system as well as the intestinal flora diversity of B. purificata were explored in present study. The results showed that the median lethal dose of P. canaliculata culture solution for B. purificata was 23.76 ind/L and a concentration-dependent damage of both the gonad and hepatopancreas were observed, the gonadal villi were dissolved and the hepatopancreas cells were broken at 20 ind/L. Furthermore, different concentrations of P. canaliculata culture solution leading to the antioxidant damage on the enzyme or non-enzyme systems of B. purificata at various degrees. Additionally, a decrease in the diversity of the intestinal flora was observed, accompanied by an increase in the abundance of pathogenic bacteria such as Pseudomonas and Aeromonas after the exposure of the culture solution of P. canaliculata. Last, after being recovered in freshwater for 24 h, the antioxidant damage of B. purificata and the disturbance of intestinal flora diversity were still not recovered especially in the high concentration group. The indirect competitive mechanism of P. canaliculata culture solution on B. purificata were explored from the aspects of tissue, biochemical level and intestinal flora, which enriched the research of P. canaliculata invasion on native snails in China, and provided new insights for the study of the invasion strategy of P. canaliculata.

Yield and quality of saffron (Crocus sativus L.) in response to priming treatments and water deficit

Despite being the most expensive spice, saffron is generally exposed to drought stress during its life cycle. The application of some effective compounds in the plants, can make it strong against environmental stresses such as water deficit. Therefore, the effect of saffron corm priming on the quantitative, qualitative, and physiological responses of this crop under drought stress was investigated in a split-plot experiment as a randomized complete block design with three replicates in two experimental years, 2022 and 2023. The treatments of the on-field experiment included 50 % Field capacity (FC) (equal to 2500 m3ha−1) and 70 % FC (equal to 3800 m3 ha−1) as the main plot and pretreatments (Corm priming) at six levels of KNO3 (3:1000), Indole-3-acetic acid (1 mg l−1), Gibberellin (300 ppm), Silicon dioxide nanoparticles (100 ppm), Hydro-priming (distilled water) and non-priming (control) as sub-plots. The results revealed the increase of petal and stigma dry weights with the application of IAA priming agents under 70 % FC irrigation as compared to 50 % FC. Based on the findings, the petal dry weights decreased, under 50 % FC in the growing season (2022 and 2023), as compared to 70 % FC conditions. Water use efficiency increased significantly with the use of IAA compared to other treatments in the second year. Water deficit led to an increase in leaf proline content and total soluble sugar. The amounts of picrocrocin improved by 5.6 % with decreasing irrigation water from 70 % to 50 % FC in both experimental years. Moreover, the highest amounts of safranal were gained when corms were exposed to IAA. Priming with IAA increased the dry weight of daughter corms compared to other priming treatments. The N and P absorbed by saffron corm decreased to 29.2 % and 28.6 % at 70 % and 50 % FC, respectively. The highest K+ uptake was recorded with the application of IAA under 70 % FC. Overall, this work indicated that an increase in saffron yield and the quality of flowers is associated with an increase in dry weight of daughter corms, ion absorption in corms and the activity of non-enzymatic defense system caused by the application of IAA under different soil moisture.

Structural characterization and antioxidant activity mechanism of the ferulic acid-rich subfraction from sugar beet pectin

The feruloylated sugar chain in sugar beet pectin (SBP) is a natural polyphenol-polysaccharide complex. Its low abundance often leads to be neglected, thereby hindering its bioactivity and mechnism research. In this study, SBP-3 A, a novel feruloylated polysaccharide fragment, was isolated from sugar beet pectin utilizing enzymatic digestion. The presence of ferulic acid on SBP-3 A was confirmed through high-performance liquid chromatography (HPLC), with a mass fraction of 22.5 μg/mg. The average molecular weight was determined to be 33.31 kDa. Methylation analysis, and nuclear magnetic resonance (NMR) spectra revealed that SBP-3 A is a heteroglycan with the main chain structure of →2)-α-Rhap-(1 → 4)-α-GalpA-(1 → 2)-α-Rhap-(1→, and the branched chain structure of ferulic acid (FA) → 3,4)-β-Galp-(1 → 2,4)-α-Rhap-(1→. Subsequently, the antioxidant activity of SBP-3 A was evaluated using the Caenorhabditis elegans (C. elegans). SBP-3 A improved antioxidant enzymes and non-enzymatic defense system, decreased reactive oxygen species levels, and up-regulated the mRNA expression of sod-3, skn-1, and daf-16, while down-regulated the expression of age-1 in C. elegans. Moreover, SBP-3 A modulated the gut flora by favorably affecting the abundances of Lactobacillus, Ligilactobacillus, and Akkermansia, thereby enhancing antioxidant capacity in C. elegans. Consequently, the aforementioned findings support the potential application of SBP-3 A as a functional food for treating oxidative stress-related illnesses.

Can Rice Growth Substrate Substitute Rapeseed Growth Substrate in Rapeseed Blanket Seedling Technology? Lesson from Reactive Oxygen Species Production and Scavenging Analysis.

Rapeseed (Brassica napus L.) seedlings suffering from inappropriate growth substrate stress will present poor seedling quality. However, the regulatory mechanism for the production and scavenging of reactive oxygen species (ROS) caused by this type of stress remains unclear. In the current study, a split plot experiment design was implemented with two crop growth substrates-a rice growth substrate (RIS) and rapeseed growth substrate (RAS)-as the main plot and two genotypes-a hybrid and an open-pollinated variety (Zheyouza 1510 and Zheyou 51, respectively)-as the sub-plot. The seedling quality was assessed, and the ROS production/scavenging capacity was evaluated. Enzymatic and non-enzymatic systems, including ascorbic acid and glutathione metabolism, and RNA-seq data were analyzed under the two growth substrate treatments. The results revealed that rapeseed seedling quality decreased under RIS, with the plant height, maximum leaf length and width, and aboveground dry matter being reduced by 187.7%, 64.6%, 73.2%, and 63.8% on average, respectively, as compared to RAS. The main type of ROS accumulated in rapeseed plants was hydrogen peroxide, which was 47.8% and 14.1% higher under RIS than under RAS in the two genotypes, respectively. The scavenging of hydrogen peroxide in Zheyouza 1510 was the result of a combination of enzymatic systems, with significantly higher peroxidase (POD) and catalase (CAT) activity as well as glutathione metabolism, with significantly higher reduced glutathione (GSH) content, under RAS, while higher oxidized glutathione (GSSH) was observed under RIS. However, the scavenging of hydrogen peroxide in Zheyou 51 was the result of a combination of elevated oxidized ascorbic acid (DHA) under RIS and higher GSH content under RAS. The identified gene expression levels were in accordance with the observed enzyme expression levels. The results suggest that the cost of substituting RAS with RIS is a reduction in rapeseed seedling quality contributing to excessive ROS production and a reduction in ROS scavenging capacity.

Phytoremediation of Pb-polluted soil using bermudagrass: Effect of mowing frequencies

Plant lead (Pb) tolerance and accumulation are key characteristics affecting phytoremediation efficiency. Bermudagrass is an excellent candidate for the remediation of Pb-polluted soil, and it needs to be mowed regularly. Here, we explored the effect of different mowing frequencies on the remediation of Pb-contaminated soil using bermudagrass. Mowing was found to decrease the biomass and photosynthetic efficiency of bermudagrass under Pb stress, thereby inhibiting its growth. Although mowing exacerbated membrane peroxidation, successive mowing treatments alleviated peroxidation damage by regulating enzymatic and nonenzymatic systems. A comprehensive evaluation of Pb tolerance revealed that all the mowing treatments reduced the Pb tolerance of bermudagrass, and a once-per-month mowing frequency had a less negative effect on Pb tolerance than did more frequent mowing. In terms of Pb enrichment, mowing significantly increased the Pb concentration, total Pb accumulation, translocation factor (TF), and bioenrichment factor (BCF) of bermudagrass. The total Pb accumulation was greatest under the once-a-month treatment, while the TF and BCF values were greatest under the three-times-a-month mowing treatment. Additionally, the decrease in soil pH and DOC were significantly correlated with the soil available Pb content and plant Pb accumulation parameters. The results showed that changes in the rhizosphere are crucial factors regulating Pb uptake in bermudagrass during mowing. Overall, once-a-month mowing minimally affects Pb tolerance and maximizes Pb accumulation, making it the optimal mowing frequency for soil Pb remediation by bermudagrass. This study provides a novel approach for the remediation of Pb-contaminated soil with bermudagrass based on mowing.

Regulation of oxidative stress response and antioxidant modification in Corynebacterium glutamicum.

As an efficient and safe industrial bacterium, Corynebacterium glutamicum has extensive application in amino acid production. However, it often faces oxidative stress induced by reactive oxygen species (ROS), leading to diminished production efficiency. To enhance the robustness of C. glutamicum, numerous studies have focused on elucidating its regulatory mechanisms under various stress conditions such as heat, acid, and sulfur stress. However, a comprehensive review of its defense mechanisms against oxidative stress is needed. This review offers an in-depth overview of the mechanisms C. glutamicum employs to manage oxidative stress. It covers both enzymatic and non-enzymatic systems, including antioxidant enzymes, regulatory protein families, sigma factors involved in transcription, and physiological redox reduction pathways. This review provides insights for advancing research on the antioxidant mechanisms of C. glutamicum and sheds light on its potential applications in industrial production.

NaHS immersion alleviates the stress effect of chromium(III) on alfalfa seeds by affecting active oxygen metabolism

ABSTRACT Objective This study aimed to investigate the regulatory effects of exogenous hydrogen sulfide (H2S) on seed germination, seedling growth, and reactive oxygen species (ROS) homeostasis in alfalfa under chromium (Cr) ion (III) stress. Methods The effects of 0–4 mM Cr(III) on the germination and seedling growth of alfalfa were first assessed. Subsequently, following seed NaHS immersion, the influence of H2S on alfalfa seed germination and seedling growth under 2 mM Cr(III) stress was investigated, and the substance contents and enzyme activities associated with ROS metabolism were quantified. Results Compared to the control group, alfalfa plant germination was delayed under 2 mM Cr(III) stress for up to 48 h (p < 0.05). At 120 h, the total seedling length was approximately halved, and the root length was roughly one-third of the control. Treatment with 0.02–0.1 mM NaHS alleviated the delay in germination and root growth inhibition caused by 2 mM Cr(III) stress, resulting in an increased ratio of root length to hypocotyl length from 0.57 to 1 above. Additionally, immersion in 0.05 mM NaHS reduced hydrogen peroxide (H2O2) and oxygen-free radicals (O2 · –) levels (p < 0.05), boosted glutathione (GSH) levels (p < 0.05), and notably enhanced catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities (p < 0.05) compared to the 2 mM Cr(III) stress treatment group. Conclusion Seed immersion in NaHS mitigated the delay in germination and inhibition of root elongation under 2 mM Cr(III) stress. This effect is likely attributed to the regulation of intracellular ROS homeostasis and redox balance through enzymatic and non-enzymatic systems; thus, providing a potential mechanism for combating oxidative stress.

Features of oxygen-independent metabolism of neutrophils in the animals sensitized with non-agglutinogenic Brucella strain

The results of evaluation of the peculiarities of functioning of non-enzymatic systems of neutrophils of peripheral blood of guinea pigs before immunization and on the 7th, 14th, 21st, 28th, 42nd, 55th, 69th, 125th days after immunization with Brucella R-strain are presented. Two groups of agouti guinea pigs were formed for the study: control and experimental. The experimental animals were immunized with a suspension of Brucella abortus strain 16/4 at a dose of 1 billion CFU/ml subcutaneously; the control pigs were intact to brucellosis. The activity of antimicrobial systems was evaluated by determining the indices of cationic proteins by photometric method in spontaneous and induced variants. Experimental samples of brucellosis antigens were used as specific inducers in the reaction procedure. It was found that the use of Brucella disintegrans at a concentration of 50 μg/ml and corpuscular antigens at a concentration of 100 μg/ml by protein in the test with cationic proteins as inducers of disintegrants has a stimulating effect on the intensity of cationic protein production in the cell suspension of leukocytes. Stimulation indices were calculated at all observation periods as the ratio of the index of the stimulated sample to the index of the sample without antigen load. Two peaks of stimulating activity of cationic proteins were observed in the course of the study: the maximum rise of stimulation indices was observed on the 14th day after immunization and a less pronounced rise on the 28th day. The peak of agglutinating antibody production was on the 21st day after immunization, complement-binding antibodies – on the 21st-28th day, less intensive rise in titers of agglutinating and complement-binding antibodies was noted on the 69th day. In these terms, a decrease in the stimulated activity of neutrophil cationic proteins was observed. The peak activity of non-enzymatic cationic proteins of neutrophils was found to be ahead of the peak of humoral immune response.

Diaminopurine in Nonenzymatic RNA Template Copying.

In the RNA World before the emergence of an RNA polymerase, nonenzymatic template copying would have been essential for the transmission of genetic information. However, the products of chemical copying with the canonical nucleotides (A, U, C, and G) are heavily biased toward the incorporation of G and C, which form a more stable base pair than A and U. We therefore asked whether replacing adenine (A) with diaminopurine (D) might lead to more efficient and less biased nonenzymatic template copying by making a stronger version of the A:U pair. As expected, primer extension substrates containing D bound to U in the template more tightly than substrates containing A. However, primer extension with D exhibited elevated reaction rates on a C template, leading to concerns about fidelity. Our crystallographic studies revealed the nature of the D:C mismatch by showing that D can form a wobble-type base pair with C. We then asked whether competition with G would decrease the mismatched primer extension. We performed nonenzymatic primer extension with all four activated nucleotides on randomized RNA templates containing all four letters and used deep sequencing to analyze the products. We found that the DUCG genetic system exhibited a more even product distribution and a lower mismatch frequency than the canonical AUCG system. Furthermore, primer extension is greatly reduced following all mismatches, including the D:C mismatch. Our study suggests that D deserves further attention for its possible role in the RNA World and as a potentially useful component of artificial nonenzymatic RNA replication systems.

The biocontrol potentiality of Bacillus amyloliquefaciens against postharvest soft rot of tomatoes and insights into the underlying mechanisms

Tomatoes can easily be affected by soft rot, one of the main postharvest infections caused by a bacterium called Pectobacterium carotovorum. This study examined the soft rot control effectiveness by Bacillus amyloliquefaciens in tomatoes, and identify the underlying action mechanisms from the perspective of the inhibition effects of antibacterial metabolites derived from B. amyloliquefaciens on pathogen and the influences of this antagonist on reactive oxygen species (ROS) scavenging capability of the fruit. The results demonstrated that B. amyloliquefaciens effectively lessened postharvest soft rot occurrence in tomatoes. The non-volatile metabolites synthesized by B. amyloliquefaciens suppressed P. carotovorum subsp. brasiliense (Pcb) growth in vitro and in vivo. The antibacterial ingredients presented in methanol-soluble sediments obtained from non-volatile metabolites. UHPLC-ESI-MS spectra revealed that the primary antibacterial ingredients were C12-C15 surfactin analogues, along with C14-C16 iturins and C16-C17 fengycins. Moreover, B. amyloliquefaciens could raise the activity of enzymatic ROS scavenging system in tomatoes, including several antioxidases and the enzymes related to glutathione peroxidase (GPX) and ascorbate-glutathione (AsA-GSH) cycles. In addition, B. amyloliquefaciens increased the levels of non-enzymatic system for ROS scavenging, including AsA and GSH. Together, O2-·production rate, H2O2 and malondialdehyde (MDA) levels were reduced. It suggested that B. amyloliquefaciens enhanced the ROS scavenging ability of tomatoes, thereby improving their resistance to the pathogen.