Respiratory Metabolism Research Articles

Antibacterial activity of Amomum tsaoko essential oil and its interaction with Staphylococcus aureus

Amomum tsaoko is a medicinal and edible plant mainly distributed in southwest China and Southeast Asia. This study investigated the antibacterial activity of Amomum tsaoko essential oil (AEO) against typical foodborne pathogenic bacteria and the interaction of AEO with Staphylococcus aureus. The results showed that AEO exhibited excellent antibacterial activity against foodborne pathogenic bacteria, with the most performance against S. aureus, with MIC and MBC values of 0.20 mg/mL and 0.39 mg/mL, respectively. In addition, the effects of AEO on S. aureus might include affecting cell membrane permeability, integrity, bacterial energy, and respiratory metabolism. Furthermore, the (E)-dec-2-enal in AEO was considered a vital antibacterial component. Overall, AEO presented positive antibacterial properties, suggesting that AEO can be served as a potential inhibitor against S. aureus and contribute to the application of AEO in food preservation.

A fast method to distinguish between fermentative and respiratory metabolisms in single yeast cells

Saccharomyces cerevisiae adjusts its metabolism based on nutrient availability, typically transitioning from glucose fermentation to ethanol respiration as glucose becomes limiting. However, our understanding of the regulation of metabolism is largely based on population averages, whereas nutrient transitions may cause heterogeneous responses. Here we introduce iCRAFT, a method that couples the ATP Förster resonance energy transfer (FRET)-based biosensor yAT1.03 with Antimycin A to differentiate fermentative and respiratory metabolisms in individual yeast cells. Upon Antimycin A addition, respiratory cells experienced a sharp decrease of the normalized FRET ratio, while respiro-fermentative cells showed no response. Next, we tracked changes in metabolism during the diauxic shift of a glucose pre-grown culture. Following glucose exhaustion, the entire cell population experienced a progressive rise in cytosolic ATP produced via respiration, suggesting a gradual increase in respiratory capacity. Overall, iCRAFT is a robust tool to distinguish fermentation from respiration, offering a new single-cell opportunity to study yeast metabolism.

Synergistic anti-infectious bronchitis virus activity of Phillygenin combined Baicalin by modulating respiratory microbiota and improving metabolic disorders

Phillygenin (PHI) and Baicalin (Bai) are the major chemical ingredients extracted from Forsythia suspensa and Scutellaria baicalensis, respectively. The mixture of Forsythia suspensa and Scutellaria baicalensis according to the theories of Traditional Chinese Veterinary Medicine, compounded formulation can effectively exert heat-clearing and detoxifying effect, but the synergistic anti-IBV activity of PHI combined with Bai was unclear. Here, the protection of PHI combined with Bai on avian infectious bronchitis virus (IBV) M41 infection and the change of respiratory microbiota and metabolomics profiles in broilers that infected with IBV were investigated. According to the experimental findings, the combination of PHI and Bai effectively alleviated broilers' slowing-growth weight and respiratory symptoms. This was accompanied by a reduction in viral copies and histopathological changes, as well as an increase of antiviral protein (G3BP1) level in tracheas and anti-IBV antibody levels in serum. In addition, 16s RNA sequencing revealed that IBV infection significantly changed respiratory microbiota composition at different taxonomic levels and respiratory metabolism composition in broilers. Interestingly, PHI combined with Bai modulated the composition of respiratory microfloras, especially the abundance of Firmicutes and Lactobacillaceae were upregulated, as well as the abundance of Proteobacteria was downregulated. The metabolomics results indicated that PHI combined with Bai involved in glucose, lipids, amino acids and nucleotide metabolism during IBV infection. In summary, PHI combined with Bai exhibited a synergistic effect on preventing infectious bronchitis (IB), with the protection being closely associated with the composition of respiratory microbiota and metabolites. Therefore, adding the mixture of PHI and Bai to the chicken drinking water is recommended to prevent and control IB in clinical.

Short-Term Benefits of Smoking Cessation Improve Respiratory Function and Metabolism in Smokers.

Cigarette smoke exposure is the main preventable cause of chronic obstructive pulmonary disease (COPD). Airflow limitation is closely associated with smoking exposure. Smoking could also interfere with lipid metabolism. To determine the respiratory functional and metabolic changes after smoking cessation in smokers in the short term. All patients were current smokers. They were assessed by spirometry and questionnaires such as COPD assessment test(CAT), modified Medical Research Council (mMRC) test for dyspnea, Fagestrom's test for nicotine dependence. Exhaled CO was detected in order to evaluate smoking exposure and smoking cessation (normal value<7 ppm). A blood sampling was eventually taken for vitamin D and cholesterol assay. All patients underwent therapy with counselling and varenicline as first-line treatment according to its schedule. Detection time: at baseline and one month after smoking cessation. All patients quit smoking during treatment. The mean age was 62 with a prevalence of males. The analysis revealed the following mean values at baseline: CAT mean score was 15, pack-years 35.5, Fagestrom's Test mean score 5.0. The West's value was 8.5, whereas Body mass index (BMI) was 25.5.Cigarette daily consumption mean value was 22.5. The comparison before and at follow up one month after smoking cessation about functional and metabolic parameters, show us the following results: FEV 1 was increased by 200 mL (p<0.02), FEF 25/75 was improved as well as mMRC test. The eCO was dropped to as low as 8 ppM. Interestingly the vitamin D level was increased from 25 to 28 ng/mL without any support therapy. The cholesterol total level was reduced and CAT value and DLCO were also significantly improved. Quit smoking is useful to improve symptoms, respiratory function and metabolic parameters in the short term.

Genome-scale metabolic models reveal determinants of phenotypic differences in non-Saccharomyces yeasts

BackgroundUse of alternative non-Saccharomyces yeasts in wine and beer brewing has gained more attention the recent years. This is both due to the desire to obtain a wider variety of flavours in the product and to reduce the final alcohol content. Given the metabolic differences between the yeast species, we wanted to account for some of the differences by using in silico models. Results We created and studied genome-scale metabolic models of five different non-Saccharomyces species using an automated processes. These were: Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora osmophila, Torulaspora delbrueckii and Kluyveromyces lactis. Using the models, we predicted that M. pulcherrima, when compared to the other species, conducts more respiration and thus produces less fermentation products, a finding which agrees with experimental data. Complex I of the electron transport chain was to be present in M. pulcherrima, but absent in the others. The predicted importance of Complex I was diminished when we incorporated constraints on the amount of enzymatic protein, as this shifts the metabolism towards fermentation.Conclusions Our results suggest that Complex I in the electron transport chain is a key differentiator between Metschnikowia pulcherrima and the other yeasts considered. Yet, more annotations and experimental data have the potential to improve model quality in order to increase fidelity and confidence in these results. Further experiments should be conducted to confirm the in vivo effect of Complex I in M. pulcherrima and its respiratory metabolism.

Inhibitory effect of tannic acid on the growth of Apiospora arundinis and 3-Nitropropionic acid production.

This study aimed to investigate the inhibitory effect of tannic acid (TA) on the growth of Apiospora arundinis and 3-Nitropropionic acid (3-NPA) production. To investigate the antifungal mechanism, the effects of TA on the hypha growth, electrical conductivity, hypha morphology, defense-related enzymes, and 3-NPA production of A. arundinis were studied. TA concentrations of 640 and 1280 μg ml-1 exhibited strong antifungal activity against A. arundinis. The results of scanning electron microscopy and transmission electron microscopy showed that the hypha of the A. arundinis was severely deformed after TA treatment, and the cell membrane was blurred and thin, vacuoles were obviously shrunken and smaller, and most of the organelles were decomposed into irregular fragments. The increased electrical conductivity and malondialdehyde content indicated that TA caused peroxidation of unsaturated fatty acids and damaged the structure of the cell membrane. The decrease of intracellular ATPase and succinate dehydrogenase content indicated that TA damaged the function of mitochondria, and participated in the inhibition of respiratory metabolism. In addition, TA significantly reduced 3-NPA production and completely inhibited 3-NPA production at 640 and 1280 μg ml-1. TA effectively inhibited both growth of A. arundinis in vitro and 3-NPA production.

Pediatric pharmaceutical interventions in self-medication: a descriptive study in community pharmacies

BackgroundThe practice of self-medication is common but not without risk, especially for vulnerable populations such as the pediatric population. Community pharmacists have an important role of vigilance in dispensing drugs available without a medical prescription, with the possibility of carrying out a Pharmaceutical Intervention (PI) if necessary. The aim of our study was to characterize the Pediatric Pharmaceutical Interventions (PPIs) in self-medication carried out during a spontaneous request for a drug at the community pharmacy.MethodsWe conducted a descriptive study in 139 pharmacies in the Auvergne-Rhône-Alpes region (France). Data were collected from students under the supervision of internship masters in the pharmacy, using the validated GIPAMED (GrId for PhArmaceutical Self-MEDication interventions) notification grid, the first week of each month, from February to May for five years (2017 to 2021). Collected data were entered on a secure university platform.ResultsOf the 3,552 PIs collected, 8,3% (n = 286) were PPIs. Of these PPIs, 35% (n = 100) was generated by requests for optional prescription drugs contraindicated by the pathophysiological condition, 28.3% for drugs requiring a prescription and 20.6% for over the counter drugs not indicated by the symptomatology. Finally, 10% of requests required a referral for a medical consultation. Four Anatomical Therapeutic Chemical (ATC) classes accounted for more than 90% of the requests: respiratory system (39.5%), alimentary tract and metabolism (19.2%), nervous system (11.5%), and musculoskeletal system (10.8%). The most common drugs generating PPIs were: ibuprofen, oxomemazine and combination camphor/essential oils, mainly due to age-related or weight-related contraindication. Paracetamol also generated PPIs frequently, mainly due to problems with drug compliance and more precise infra-therapeutic doses. When these PPIs were dispensed, the pharmacist’s proposed solutions were accepted in 94.8% (n = 271) of the cases.ConclusionsThe community pharmacist has an important role in providing information about medicines and their correct use to patients. Our research shows that this attention benefits vulnerable populations, such as children, even for drugs that are widely used (e.g. paracetamol and non-steroidal anti-inflammatory drugs) or active substances for which there are age-related or weight-related contraindications (e.g. antitussives, camphor combinations).

Effects of acute hypoxic post-feeding condition on respiratory metabolism and digestion in yellow catfish (Pelteobagrus fulvidraco)

In this study, acute hypoxia was applied to two states of yellow catfish (Pelteobagrus fulvidraco) (non-feeding and feeding) for 48 h. We investigated the effects of acute hypoxia on the respiratory metabolism and digestive ability of yellow catfish (mean body length: 7.61 ± 0.52 cm). The results indicated that the respiratory frequency of yellow catfish under acute hypoxic post-feeding condition was rapidly accelerated and the oxygen consumption rate was reduced. The level of succinate dehydrogenase in the gills first increased and then significantly decreased (p < 0.05) and the level of lactate dehydrogenase significantly increased (p < 0.05). When the expression level of hypoxia-inducing factor was significantly increased (p < 0.05), the downstream coding genes (hexokinase 1 (hk1), phosphofructokinase (pfkla), and pyruvate kinase M1/2a (pkma)), key molecules of glycolysis, and the activity of crucial enzymes (hexokinase, phosphofructokinase, and pyruvate kinase) increased. At the same time, the glucose level dropped and the lactic acid level increased, indicating that the metabolic mode in the gills of yellow catfish under acute hypoxic post-feeding condition gradually changed to anaerobic, and the anaerobic glycolysis process was activated to provide the required energy for the body. In addition, we found that the activity of digestive enzymes (trypsin, lipase, and amylase) and expression levels of digestive genes (trypsin, lipase, and amylase) were inhibited in the liver and intestine of yellow catfish under the acute hypoxic post-feeding condition, indicating that their digestive ability was reduced. This may adversely affect growth and development. This study analyzed the effects of acute hypoxic post-feeding exposure on the respiratory metabolism and digestive capacity of yellow catfish, providing new insights into fish physiology and sustainable fish culture.

Effect of florfenicol administered through feed on Atlantic salmon (Salmo salar) gut and its microbiome

Although concerns about the impacts of antibiotics in aquatic organisms are reported worldwide, the potential adverse effects on fish gut microbial communities and fish health are still not well known. In this study, we investigated the effects of florfenicol (FFC) on the gut microbiome and gastrointestinal (GIT) gene expression in juvenile Atlantic salmon (Salmo salar). Three doses of FFC were used to coat experimental feed at 10, 20 and 30 mg/kg/ fish body weight (bw). The feed was administered for 18 days, followed by a 10-day recovery period. The metatranscriptome analysis revealed that 10 and 30 mg/kg bw of FFC led to the downregulation of genes involved in the transcription of NADH-ubiquinone oxidoreductase chain-1, suggesting that the antibiotic targets bacterial respiratory metabolism. The 30 mg/kg bw FFC treatment upregulated genes that encode glycolytic enzymes, such as phosphoglycerate kinase, indicating a disruption of energy metabolism in the microbiome. Analysis of the fish host transcriptome showed that the FFC treatment affected cellular processes in the GIT system of fish, including pathways related to apoptosis and DNA metabolism. The 30 mg/kg bw FFC treatment specifically activated pathways related to cellular regulation, including LXR/RXR activation, FXR/RXR activation, and protein ubiquitination. At the end of the recovery phase, the 30 mg/kg bw FFC treated group altered pathways related to EIF2 signaling and lysine degradation.This study identified molecular-level effects of FFC treatment on the gut microbiome and the GIT of juvenile Atlantic salmon, although phenotypic changes in growth or condition were not observed. Most of the observed changes were reversible and receded at the end of the recovery period, apart from the highest treatment group. These findings emphasize the importance of understanding the molecular mechanisms that underlie the potential effects of antibiotics in order to optimize antibiotic treatments in aquaculture.

Adaptation to sorbic acid in low sugar promotes resistance of yeast to the preservative

The weak acid sorbic acid is a common preservative used in soft drink beverages to control microbial spoilage. Consumers and industry are increasingly transitioning to low-sugar food formulations, but potential impacts of reduced sugar on sorbic acid efficacy are barely characterised. In this study, we report enhanced sorbic acid resistance of yeast in low-glucose conditions. We had anticipated that low glucose would induce respiratory metabolism, which was shown previously to be targeted by sorbic acid. However, a shift from respiratory to fermentative metabolism upon sorbic acid exposure of Saccharomyces cerevisiae was correlated with relative resistance to sorbic acid in low glucose. Fermentation-negative yeast species did not show the low-glucose resistance phenotype. Phenotypes observed for certain yeast deletion strains suggested roles for glucose signalling and repression pathways in the sorbic acid resistance at low glucose. This low-glucose induced sorbic acid resistance was reversed by supplementing yeast cultures with succinic acid, a metabolic intermediate of respiratory metabolism (and a food-safe additive) that promoted respiration. The results indicate that metabolic adaptation of yeast can promote sorbic acid resistance at low glucose, a consideration for the preservation of foodstuffs as both food producers and consumers move towards a reduced sugar landscape.

A flexible partially linear regression with random effects for bimodal data with application in postharvest

In the postharvest area of agricultural products, it is common to have data sets in which the dependent variable in general may not be symmetrical and unimodal, therefore, the use of usual regression models is not always appropriate. In addition, the data can also have repeated measurements over time. With this in mind, the aim of this article is to propose a partially linear regression model with random effects for postharvest bimodal data, this extended regression is based on the Birnbaum–Saunders distribution. Additionally we present different mathematical properties of this new model. To verify the impartiality and accuracy of the estimators, a simulation study was carried out. The parameters of partially linear regression with random effects are estimated using the penalized maximum likelihood. The results of the developed model are presented empirically and indicate that the storage temperature can cause a significant change in the lychee’s respiratory metabolism. Thus, according to the model selection and residue analysis measures, it can be concluded that the proposed model is a statistical tool for postharvest data, providing an adequate analysis.

Spermosphere bacterial community at different germination stages of Ormosia henryi and its relationship with seed germination

Based on the important role of spermosphere microbes in seed germination, the driving factors of seed germination were explored under the influence of spermosphere bacteria by studying the time series changes of spermosphere bacterial communities in different germination stages of Ormosia henryi seeds. In this study, the soils under the mother trees of O. henryi in three places (Guanling, Qinglong, Shiqian in Guizhou, China) were used as the seed germination substrates to determine the spermosphere bacterial samples in different germination stages of Ormosia henryi seeds, and bioinformatics strategies were used to analyze bacterial diversity and its relationship with soil nutrients and germination rate, bacterial function prediction and microbial network characteristics. The results showed that seed germination rate of O. henryi was affected by both soil nutrients and abundance and species of spermosphere bacteria, most of the spermosphere bacteria that contributed the most to seed germination time had the functions of degradation and bioremediation. The spermosphere bacterial functions of respiratory metabolism, nodulation, degradation and energy were enhanced during seed germination. The spermosphere bacterial community reached a more stable state under the influence of germinating seeds during the stage of imbibition. This study revealed the contribution of spermosphere bacteria function, abundance and species to the germination rate and germination stage of O.henryi, providing a theoretical basis for screening and application of spermosphere functional bacteria.

Cucumber malate decarboxylase, CsNADP-ME2, functions in the balance of carbon and amino acid metabolism in fruit

Abstract Central metabolism produces carbohydrates and amino acids that are tightly correlated to plant growth and thereby crop productivity. Malate is reported to link mitochondrial respiratory metabolism with cytosolic biosynthetic pathways. Although the function of malate metabolism-related enzymes in providing carbon has been characterized in some plants, evidence for this role in the fleshy fruit of cucumber is lacking. Here, radiolabeled bicarbonate fed into the xylem stream from the cucumber roots was incorporated into amino acids, soluble sugars, and organic acids in the exocarp and vasculature of fruits. The activities of decarboxylases, especially decarboxylation from NADP-dependent malic enzyme (NADP-ME), were higher in cucumber fruit than in the leaf lamina. Histochemical localization revealed that CsNADP-ME2 was mainly located in the exocarp and vascular bundle system of fruit. Radiotracer and gas-exchange analysis indicated that overexpression of CsNADP-ME2 could promote carbon flux into soluble sugars and starch in fruits. Further studies combined with metabolic profiling revealed that the downregulation of CsNADP-ME2 in RNA interference (RNAi) lines caused the accumulation of its substrate, malate, in the exocarp. In addition to inhibition of glycolysis-related gene expression and reduction of the activities of the corresponding enzymes, increased amino acid synthesis and decreased sugar abundance were also observed in these lines. The opposite effect was found in CsNADP-ME2-overexpressing lines, suggesting that there may be a continuous bottom-up feedback regulation of glycolysis in cucumber fruits. Overall, our studies indicate that CsNADP-ME2 may play potential roles in both central carbon reactions and amino acid metabolism in cucumber fruits.

Acidic electrolyzed water treatment delays the senescence of ‘Lingwu long’ jujube fruit during cold storage by regulating energy and respiratory metabolism

Jujube fruit may rapidly undergo maturity and senescence during storage, seriously affecting its commercialization. The study aimed to evaluate the role of acidic electrolyzed water (AEW) on energy and respiratory metabolism, and senescence in jujube fruit during cold storage. The results indicated that AEW improved ATP content and energy charge via increasing succinate dehydrogenase, cytochrome C oxidase, H+-ATPase, and Ca2+-ATPase activities and delayed jujube fruit senescence. The treatment was found to improve the activities of nicotinamide adenine dinucleotide kinase, 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase, and the content of NADPH, and reduce oxidative stress. Transcriptome analysis suggested that AEW regulated the expression of the genes associated with glycolysis, citrate cycle, pentose phosphate pathway, oxidative phosphorylation, ROS metabolism, transcription factors, phenylpropane biosynthesis, cell wall metabolism, and plant hormone signal transduction. Therefore, we concluded that AEW may delay the senescence of postharvest jujube fruit by regulating expression of the relevant genes and metabolic pathways.

Confining Prepared Ultra-Small Nanozymes Loading Ato for Lung Cancer Catalytic Therapy/Immunotherapy.

Nanozymes with inherent enzyme-mimic catalytic properties combat malignant tumor progression via catalytic therapy, while the therapeutic efficacy still needs to be improved. In this work, we innovatively synthesized ultra-small platinum nanozymes (nPt) in confined domain of wormlike pore channel in gold nanobipyramidal-mesoporous silica dioxide nanocomposites, producing nanozyme carriers AP-mSi with photo-enhanced peroxidase ability. Afterwards, based on the prepared AP-mSi, the lung cancer nanozymes probe (AP-HAI) was ingeniously produced by removing SiO2 template, modifying HSA, and loading ATO as well as IR780. Under NIR light irradiation, inner AuP and IR780 collaborated for photothermal process, thus facilitating the peroxidase-like catalytic process of H2 O2 . Additionally, loaded atovaquone molecules (ATO), a cell respiration inhibitor, could impair tumor respiration metabolism and cause oxygen retention, hence enhancing IR780's PDT effectiveness. In a result, IR780's PDT property and nPt nanozymes' photo-enhanced peroxidase-like ability endowed probes a high ROS productivity, eliciting anti-tumor immune responses to destroy tumor tissue. Systematic studies revealed that the obvious ROS generation was obtained by the strategy of using nPt nanozymes and reducing oxygen consumption by ATO, which in turn enabled lung cancer synergetic catalytic therapy/ICD-based immunotherapy. The results of this work would provide theoretical justification for the practical use of photo-enhanced nanozyme probes. This article is protected by copyright. All rights reserved.

Priming methods affected deterioration speed of primed rice seeds by regulating reactive oxygen species accumulation, seed respiration and starch degradation.

Seed priming is a pre-sowing seed treatment that is beneficial for rice seed germination and seedling growth, but the reduced seed longevity after seed priming greatly limited its adoption. The deterioration of primed seeds showed large differences among different studies, and the priming method might play an important role in regulating the deterioration speed of primed seeds. However, whether and how the priming method affected the deterioration of primed rice seeds during storage remains unknown. In this study, two typical seed priming methods, namely hydropriming (HP) and osmopriming (PEG) were compared under artificially accelerated aging conditions, the changes in germination performance, starch metabolism, seed respiration and reactive oxygen species accumulation before and after accelerated aging were determined. Hydroprimed rice seeds exhibited significantly faster deterioration speed than that of PEG-primed seeds in terms of germination speed and percentage. Meanwhile, α-amylase activity and total soluble sugar content in hydroprimed seeds were reduced by 19.3% and 10.0% respectively after aging, as compared with PEG-primed seeds. Such effects were strongly associated with the increased reactive oxygen generation and lipid peroxidation, as the content of superoxide anion, hydrogen peroxide and malondialdehyde in hydroprimed seeds were 4.4%, 12.3% and 13.7% higher than those in PEG-primed seeds after aging, such effect could be attributed to the increased respiratory metabolism in hydroprimed seeds. In addition, the simultaneous use of N-acetylcysteine with HP and PEG priming greatly inhibited the deterioration of primed rice seeds, suggesting that the ability to scavenge reactive oxygen species may be the key factor affecting the speed of deterioration in primed rice seeds during storage.

Sex-specific metabolic adaptations in transgenic mice overexpressing cytochrome b5 reductase-3.

Cytochrome b5 reductase 3 (CYB5R3) activates respiratory metabolism in cellular systems and exerts a prolongevity action in transgenic mice overexpressing this enzyme, mimicking some of the beneficial effects of calorie restriction. The aim of our study was to investigate the role of sex on metabolic adaptations elicited by CYB5R3 overexpression, and how key markers related with mitochondrial function are modulated in skeletal muscle, one of the major contributors to resting energy expenditure. Young CYB5R3 transgenic mice did not exhibit the striking adaptations in carbon metabolism previously detected in older animals. CYB5R3 was efficiently overexpressed and targeted to mitochondria in skeletal muscle from transgenic mice regardless sex. Overexpression significantly elevated NADH in both sexes, although differences were not statistically significant for NAD+, and increased the abundance of cytochrome c and the fission protein DRP-1 in females but not in males. Moreover, while mitochondrial biogenesis and function markers (as TFAM, NRF-1 and cleaved SIRT3) were markedly upregulated by CYB5R3 overexpression in females, a downregulation was observed in males. Ultrastructural changes were also highlighted, with an increase in the number of mitochondria per surface unit, and in the size of intermyofibrillar mitochondria in transgenic females compared with their wild-type controls. Our results support that CYB5R3 overexpression upregulates markers consistent with enhanced mitochondrial biogenesis and function, and increases mitochondrial abundance in skeletal muscle, producing most of these potentially beneficial actions in females.

Mitochondrial structure and respiratory metabolism in cold resistance of alfalfa seedling root

Mitochondrial structure and respiratory metabolism in cold resistance of alfalfa seedling root

Enhanced methane oxidation efficiency by digestate biochar in landfill cover soil: Microbial shifts and carbon metabolites insights

The ability of biochar to enhance the oxidation of methane (CH4) in landfill cover soil by promoting the growth and activity of methane-oxidizing bacteria (MOB) has attracted significant attention. However, the optimal characteristics of digestate-derived biochar (DBC) for promoting the MOB community and CH4 removal performance remain unclear. This study examined how the CH4 oxidation capacity and respiratory metabolism of MOB life process are affected by the application of DBC compared with the most commonly used woody-derived biochar (WBC). The addition of both WBC and DBC enhanced CH4 oxidation, with DBC exhibiting a nearly twofold increase in cumulative CH4 oxidation mass (7.14 mg CH4 g−1) compared to WBC. The high ion-exchange capacity of DBC was found to be more favorable for the growth of Type I MOB, which have more efficient metabolic pathways for CH4 oxidation. Type I MOB which are abundant in DBC may prefer monovalent positive ions, while the charge-rich nature of DBC may also have hindered extracellular protein aggregation. The superiority of DBC in terms of CH4 oxidation thus highlights the underlying mechanisms of biochar-MOB interactions, offering potential biochar options for landfill cover soil.

Transcriptome analysis reveals the mechanism of polyethylene atmosphere packaging delaying browning of postharvest Pleurotus eryngii

To elucidate the mechanism of low-density polyethylene(LDPE) atmosphere packaging on delaying browning of Pleurotus eryngii under a postharvest low-temperature storage, this study focused on exploring the effects of two thicknesses (0.02 and 0.05 mm) LDPE packaging on some antioxidant enzymes, and stress markers in P. eryngii. The results showed that LDPE atmosphere packaging maintained the phenolic content and higher superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) levels, reduced malondialdehyde (MDA) content, electrolyte leakage rate and polyphenol oxidase (PPO) levels in the mushroom. Also, transcriptome analyses showed that LDPE atmosphere packaging regulated the expression of enzymes PPO, POD, CAT and APX-related genes, inhibited the expression of lipoxygenases (LOX) and phospholipase D (PLD)-related genes and regulated the l-glutathione (GSH) antioxidant system. Overall, LDPE atmosphere packaging delayed the reduction of unsaturated fatty acids and energy loss by maintaining the integrity of cell membranes and regulating important genes involved in membrane lipid metabolism, energy metabolism, and respiratory metabolism of P. eryngii. In addition, it activated the expression of genes related to GSH synthesis and metabolism, thus enhancing the antioxidant capacity of mushroom body, reducing the accumulation of ROS and delaying browning.