Imbalance of mitochondrial quality control regulated by STING and PINK1 affects cyfluthrin-induced neuroinflammation.

Nervous system diseases are a global health problem, and with the increase in the elderly population around the world, their incidence will also increase. Harmful substances in the environment are closely related to the occurrence of nervous system diseases. China is a large agricultural country, and thus the insecticide cyfluthrin has been widely used. Cyfluthrin is neurotoxic, but the mechanism of this injury is not clear. Inflammation is an important mechanism for the occurrence of nervous system diseases. Mitochondria are the main regulators of the inflammatory response, and various cellular responses, including autophagy, directly affect the regulation of inflammatory processes. Mitochondrial damage is related to mitochondrial quality control (MQC) and PTEN-induced kinase 1 (PINK1). As an anti-inflammatory factor, stimulator of interferon genes (STING) participates in the regulation of inflammation. However, the relationship between STING and mitochondria in the process of cyfluthrin-induced nerve injury is unclear. This study established in vivo and in vitro models of cyfluthrin exposure to explore the role of MQC and to clarify the mechanism of action of STING and PINK1. Our results showed that cyfluthrin can increase the reactive oxygen species (ROS) level, resulting in mitochondrial damage and inflammation. In this process, an imbalance in MQC leads to the aggravation of mitochondrial damage, and high STING expression drives the occurrence of inflammation. We established a differential expression model of STING and PINK1 to further determine the underlying mechanism and found that the interaction between STING and PINK1 regulates MQC to affect the levels of mitochondrial damage and inflammation. When STING and PINK1 expression are downregulated, mitochondrial damage and STING-induced inflammation are significantly alleviated. In summary, a synergistic effect between STING and PINK1 on cyfluthrin-induced neuroinflammation may exist, which leads to an imbalance in MQC by inhibiting mitochondrial biogenesis and division/fusion, and PINK1 can reduce STING-driven inflammation.

Revealing the spoilage characteristics of refrigerated prepared beef steak by advanced bioinformatics tools.

BACKGROUND: Although microorganisms are the main cause of spoilage in prepared beef steaks, very few deep spoilage mechanisms have been reported so far. Aiming to unravel the mechanisms during 12 days of storage at 4 °C affecting the quality of prepared beef steak, the present study investigated the changes in microbial dynamic community using a combined high-throughput sequencing combined and bioinformatics. In addition, gas chromatography-mass spectrometry combined with multivariate statistical analysis was utilized to identify marker candidates for prepared steaks. Furthermore, cloud platform analysis was applied to determine prepared beef steak spoilage, including the relationship between microbiological and physicochemical indicators and volatile compounds. RESULTS: The results showed that the dominant groups of Pseudomonas, Brochothrix thermosphacta, Lactobacillus and Lactococcus caused the spoilage of prepared beef steak, which are strongly associated with significant changes in physicochemical properties and volatile organic compounds (furan-2-pentyl-, pentanal, 1-octanol, 1-nonanol and dimethyl sulfide). Metabolic pathways were proposed, among which lipid metabolism and amino acid metabolism were most abundant. CONCLUSION: The present study is helpful with respect to further understanding the relationship between spoilage microorganisms and the quality of prepared beef steak, and provides a reference for investigating the spoilage mechanism of dominant spoilage bacteria and how to extend the shelf life of meat products. © 2024 Society of Chemical Industry.

Association between gut microbiota and acute pancreatitis: a bidirectional Mendelian randomization study.

BACKGROUND AND AIM: The dysbiosis of gut microbiota has been reported in acute pancreatitis. However, the direction and magnitude between host microbiota and pancreas remains to be established. This study investigated the association between gut microbiota and acute pancreatitis using Mendelian randomization (MR) methods. METHODS: Summary statistics of gut microbiota abundance and acute pancreatitis were extracted from genome-wide association studies (GWAS). The two-sample bidirectional MR design was employed to assess genetic association between the microbiota and pancreatitis, followed by a comprehensive sensitivity analysis to verify the robustness of the results. RESULTS: Seven microbiota taxa have been identified as significantly associated with the development of pancreatitis. Host genetic-driven order Bacteroidales and class Bacteroidia are associated with an increased risk of pancreatitis. The genera Coprococcus and Eubacterium fissicatena group also exhibit a positive effect on the development of pancreatitis, while the genera Prevotella, Ruminiclostridium, and Ruminococcaceae act as protective factors against pancreatitis. In contrast, acute pancreatitis was positively correlated with phylum Proteobacteria and genus Lachnospiraceae and negatively correlated with genus Holdemania. CONCLUSIONS: The bidirectional relationship between gut microbiota and acute pancreatitis suggests a critical role for host-microbiota crosstalk in the development of the disease. Targeted modulation of specific gut microbiota enables the prevention and treatment of acute pancreatitis.

Inflammation and endothelial function relevant genetic polymorphisms, carotid atherosclerosis, and vascular events in high-risk stroke population.

Aim: To identify the associations of 19 single nucleotide polymorphisms (SNPs) in genes involved in inflammation and endothelial function and carotid atherosclerosis with subsequent ischemic stroke and other vascular events in the high-risk stroke population. Methods: This was a multicenter community-based sectional survey and prospective cohort study in Sichuan, southwestern China. Eight communities were randomly selected, and the residents in each community were surveyed using a structured face-to-face questionnaire. Carotid ultrasonography and DNA information were obtained from 2,377 out of 2,893 individuals belonging to a high-risk stroke population. Genotypes of the 19 SNPs in genes involved in inflammation and endothelial function were measured. All the 2,377 subjects were followed up for 4.7 years after the face-to-face survey. The primary outcome was ischemic stroke, and the secondary outcome was a composite of vascular events. Results: Among the 2,377 subjects, 2,205 (92.8%) completed a 4.7-year follow-up, 947 (42.9%) had carotid atherosclerosis [372 (16.9%) carotid vulnerable plaque, 405 (18.4%) mean IMT > 0.9 mm, 285 (12.0%) carotid stenosis ≥15%]. Outcomes occurred in 158 (7.2%) subjects [92 (4.2%) ischemic stroke, 17 (0.8%) hemorrhagic stroke, 48 (2.2%) myocardial infarction, and 26 (1.2%) death] during follow-up. There was a significant gene-gene interaction among ITGA2 rs1991013, IL1A rs1609682, and HABP2 rs7923349 in the 19 SNPs. The multivariate logistic regression model revealed that carotid atherosclerosis and the high-risk interactive genotypes among the three SNPs were independent with a higher risk for ischemic stroke (OR = 2.67, 95% CI: 1.52-6.78, p = 0.004; and OR = 3.11, 95% CI: 2.12-9.27, p < 0.001, respectively) and composite vascular events (OR = 3.04, 95% CI: 1.46-6.35, p < 0.001; and OR = 3.23, 95% CI: 1.97-8.52, p < 0.001, respectively). Conclusion: The prevalence of carotid atherosclerosis was shown to be very high in the high-risk stroke population. Specific SNPs, interactions among them, and carotid atherosclerosis were independently associated with a higher risk of ischemic stroke and other vascular events.

[H3K27 acetylation promotes lncRNA OIP5-AS1 transcription and induces apoptosis of nasal epithelial cells in allergic rhinitis through up-regulation of TLR4].

Objective To investigate the effect of lysine 27 residue of histone H3 (H3K27) acetylation modification on the transcriptional promotion of long noncoding RNA OPA interacting protein 5-antisense RNA 1 (lncRNA OIP5-AS1) and apoptosis of nasal epithelial cells (NECs) in allergic rhinitis (AR) via regulating Toll-like receptor 4 (TLR4). Methods Interleukin-13 (IL-13) was used to treat NECs to establish an AR cell model. Real-time quantitative PCR was utilized to detect the expressions of OIP5-AS1 and TLR4 in nasal mucosal tissues of AR patients and in the in vitro cell model. The concentrations of macrophage colony-stimulating factor (GM-CSF), eotaxin-1, and mucin 5AC (MUC5AC) were detected by ELISA. The apoptosis of NECs was determined by terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL). A dual-luciferase report experiment was carried out to verify the relationship between OIP5-AS1 and TLR4. Chromatin immunoprecipitation (ChIP) assay was performed to verify H3K27 acetylation of histones in the OIP5-AS1 promoter region. Results Compared with healthy controls and untreated NECs, OIP5-AS1 and TLR4 were both up-regulated in nasal mucosal tissues from AR patients and IL-13-stimulated NECs. Knockdown of OIP5-AS1 decreased the level of TLR4 in IL-13-treated NECs, while overexpression of OIP5-AS1 increased the level of TLR4. Inhibition of OIP5-AS1 reduced the apoptosis rate, and inhibited the secretion of GM-CSF, eotaxin-1, and MUC5AC from IL-13-treated NECs, while overexpression of TLR4 partially reversed the effects of OIP5-AS1 knockdown on NEC apoptosis and the secretion of GM-CSF, eotaxin-1, and MUC5AC. In addition, H3K27 acetylation was markedly enriched in the promoter region of OIP5-AS1, and H3K27 acetylation promoted the expression of OIP5-AS1 in IL-13-treated NECs. Conclusion H3K27 acetylation promotes OIP5-AS1 transcription and induces NEC apoptosis in AR via upregulation of TLR4.

Insight into the evolution of textural properties and juiciness of ready-to-eat chicken breasts upon different thermal sterilization: From the perspective of protein degradation.

Texture deterioration of meat products upon high-temperature sterilization is a pressing issue in the meat industry. This study evaluated the effect of different thermal sterilization temperatures on the textural and juiciness of ready-to-eat (RTE) chicken breast. In this study, by dynamically monitoring the texture and juiciness of chicken meat products during the process of thermal sterilization, it has been observed that excessively high sterilization temperatures (above 100°C) significantly diminish the shear force, springiness and water-holding capacity of the products. Furthermore, from the perspective of myofibrillar protein degradation, molecular mechanisms have been elucidated, unveiling that the thermal sterilization treatment at 121°C/10 min triggers the degradation of myosin heavy chains and F-actin, disrupting the lattice arrangement of myofilaments, compromising the integrity of sarcomeres, and resulting in an increase of approximately 40.66% in the myofibrillar fragmentation index, thus diminishing the quality characteristics of the products. This study unravels the underlying mechanisms governing the dynamic changes in quality of chicken meat products during the process of thermal sterilization, thereby providing theoretical guidance for the development of high-quality chicken products.

Treatment failure is a key factor in the development of Helicobacter pylori resistance.

BACKGROUND: Helicobacter pylori eradication failure influences its antibiotic resistance. AIMS: This study aimed to evaluate the effect of previous treatment failures on it, including the changes in the antibiotic resistance rates, minimal inhibitory concentration (MIC) distributions, and resistance patterns. MATERIALS AND METHODS: This single-center retrospective study included 860 primary isolates and 247 secondary isolates. Antibiotic susceptibility testing was performed for amoxicillin, metronidazole, clarithromycin, levofloxacin, furazolidone, tetracycline, and rifampicin. The demographic data and detailed regimens were collected. RESULTS: The primary resistance rates to amoxicillin, metronidazole, clarithromycin, levofloxacin, tetracycline, rifampin, and furazolidone were 5.93%, 83.84%, 28.82%, 26.28%, 0.35%, 1.16%, and 0%, while secondary were 25.10%, 92.31%, 79.76%, 63.16%, 1.06%, 3.19%, and 0%, respectively. The resistance rates to amoxicillin, metronidazole, clarithromycin, and levofloxacin increased significantly with the number of treatment failures accumulated, and showed a linear trend. The proportion of primary and secondary multidrug-resistant (MDR) isolates were 17.79% and 63.16%, respectively. The MIC values of amoxicillin, clarithromycin, and levofloxacin were elevated significantly with medication courses increased. CONCLUSION: The prevalence of amoxicillin, clarithromycin, levofloxacin, and metronidazole resistance would increase rapidly following first-line treatment failure, as well as the MIC values of them. Clinicians should pay great attention to the first-line treatment to cure H. pylori infection successfully.

Radiofrequency ablation with or without transarterial chemoembolization for hepatocellular carcinoma meeting Milan criteria: a focus on tumor progression and recurrence patterns.

Background/objective: The aim of this study was to evaluate tumor progression and recurrence patterns of radiofrequency ablation (RFA) with or without transarterial chemoembolization (TACE) for treating hepatocellular carcinoma (HCC) that meets Milan criteria. Methods: This retrospective study included consecutive HCC patients meeting Milan criteria who underwent percutaneous RFA with or without TACE as initial treatment at a tertiary academic center between December 2017 and 2022. Technical success rate, local recurrence-free survival (LRFS), progression-free survival (PFS) and recurrence patterns were recorded. Results: A total of 135 HCC patients (109 male [80.7%]) with a mean age of 62 years and 147 target lesions were retrospectively enrolled. The technical success rate was 99.3%. The median LRFS was 60 months, and the cumulative 1-, 3-, and 5-year LRFS were 88.9%, 70.1%, and 30.0%, respectively. Additionally, the median PFS was 23 months, with cumulative 1-, 3-, and 5-year PFS of 74%, 30%, and 0%, respectively. Multivariate analysis confirmed that age > 60, alpha-fetoprotein (AFP) (> 10), and albumin were associated with PFS (2.34, p = 0.004; 1.96, p = 0.021; 0.94, p = 0.007, respectively). Six recurrence patterns were identified: local tumor progression (LTP) alone (n = 15, 25.0%), intrahepatic distant recurrence (IDR) alone (n = 34, 56.7%), extrahepatic recurrence (ER) alone (n = 2, 3.3%), IDR + ER (n = 2, 3.3%), LTP + IDR (n = 5, 8.8%), and LTP + IDR + ER (n = 2, 3.3%). IDR occurred most frequently as a sign of good local treatment. Conclusions: RFA in combination with TACE does not appear to provide an advantage over RFA alone in improving tumor progression in patients with HCC meeting the Milan criteria. However, further prospective studies are needed to confirm these findings and to determine the optimal treatment approach for this patient population.

A Self-Delivery Nanodrug Simultaneously Inhibits COX-2/PGE2 Mediated Inflammation and Downregulates PD-L1 to Boost Photoimmunotherapy.

Phototherapy promotes anti-tumor immunity by inducing immunogenic cell death (ICD), However, the accompanying inflammatory responses also trigger immunosuppression, attenuating the efficacy of photo-immunotherapy. Herein, they co-assembled a cell-membrane targeting chimeric peptide C16-Cypate-RRKK-PEG8-COOH (CCP) and anti-inflammatory diclofenac (DA) to develop a nanodrug (CCP@DA) that both enhances the immune effect of phototherapy and weakens the inflammation-mediated immunosuppression. CCP@DA achieves cell membrane-targeting photodynamic and photothermal synergistic therapies to damage programmed death ligand 1 (PD-L1) and induce a strong ICD to activate anti-tumor response. Simultaneously, the released DA inhibits the cycoperoxidase-2 (COX-2)/prostaglandin E2 (PGE2) pathway in tumor cells to inhibit pro-tumor inflammation and further down-regulate PD-L1 expression to relieve the immunosuppressive microenvironment. CCP@DA significantly inhibited tumor growth and inflammation both in vitro and in vivo, while maintaining a potent anti-tumor immune response. Additionally, it exhibits excellent anti-metastatic capabilities and prolongs mouse survival time with a single dose and low levels of near-infrared (NIR) light exposure. This work provides a valuable strategy to control the therapy-induced inflammation for high-efficiency photoimmunotherapy.

Low-Symmetry 2D t-InTe for Polarization-Sensitive UV-Vis-NIR Photodetection.

Polarization-sensitive photodetection grounded on low-symmetry 2D materials has immense potential in improving detection accuracy, realizing intelligent detection, and enabling multidimensional visual perception, which has promising application prospects in bio-identification, optical communications, near-infrared imaging, radar, military, and security. However, the majority of the reported polarized photodetection are limited by UV-vis response range and low anisotropic photoresponsivity factor, limiting the achievement of high-performance anisotropic photodetection. Herein, 2D t-InTe crystal is introduced into anisotropic systems and developed to realize broadband-response and high-anisotropy-ratio polarized photodetection. Stemming from its narrow band gap and intrinsic low-symmetry lattice characteristic, 2D t-InTe-based photodetector exhibits a UV-vis-NIR broadband photoresponse and significant photoresponsivity anisotropy behavior, with an exceptional in-plane anisotropic factor of 1.81@808 nm laser, surpassing the performance of most reported 2D counterparts. This work expounds the anisotropic structure-activity relationship of 2D t-InTe crystal, and identifies 2D t-InTe as a prospective candidate for high-performance polarization-sensitive optoelectronics, laying the foundation for future multifunctional device applications.

[Effects of Modified Distillers' Grains Biochar on Cadmium Forms in Purple Soil and Cadmium Uptake by Rice].

Biochar and modified biochar have been widely used as remediation materials in heavy metal-contaminated agricultural soils. In order to explore economical and effective materials for the remediation of cadmium (Cd)-contaminated acidic purple soil, distillers 'grains were converted into distillers' grains biochar (DGBC) and modified using nano-titanium dioxide (Nano-TiO2) to produce two types of modified DGBCs:TiO2/DGBC and Fe-TiO2/DGBC. A rice pot experiment was used to investigate the effects of different biochar types and application rates (1%, 3%, and 5%) on soil properties, nutrient content, Cd bioavailability, Cd forms, rice growth, and Cd accumulation. The results showed that:① DGBC application significantly increased soil pH, cation exchange capacity (CEC), and nutrient content, with TiO2/DGBC and Fe-TiO2/DGBC exhibiting better effects. ② DGBC and modified DGBCs transformed Cd from soluble to insoluble forms, increasing residual Cd by 1.22% to 18.46% compared to that in the control. Cd bioavailability in soil decreased significantly, with available cadmium being reduced by 11.81% to 23.67% for DGBC, 7.64% to 43.85% for TiO2/DGBC, and 19.75% to 55.82% for Fe-TiO2/DGBC. ③ DGBC and modified DGBCs increased rice grain yield, with the highest yields observed at a 3% application rate:30.60 g·pot-1 for DGBC, 37.85 g·pot-1 for TiO2/DGBC, and 39.10 g·pot-1 for Fe-TiO2/DGBC, representing 1.13, 1.40, and 1.44 times the control yield, respectively. Cd content in rice was significantly reduced, with grain Cd content ranging from 0.24 to 0.30 mg·kg-1 for DGBC, 0.16 to 0.26 mg·kg-1 for TiO2/DGBC, and 0.14 to 0.24 mg·kg-1 for Fe-TiO2/DGBC. Notably, Cd content in rice grains fell below the food safety limit of 0.2 mg·kg-1 (GB2762-2022) at 5% for TiO2/DGBC and 3% and 5% for Fe-TiO2/DGBC. In conclusion, Nano-TiO2 modified DGBC effectively reduced the bioavailability of soil Cd through its own adsorption and influence on soil Cd forms distribution, thus reducing the absorption of Cd by rice and simultaneously promoting rice growth and improving rice yield. It is a type of Cd-contaminated soil remediation material with a potential application prospect. The results can provide scientific basis for farmland restoration and agricultural safety production of Cd-contaminated acidic purple soil.

TACE-assisted multi-image guided radiofrequency ablation for the treatment of single hepatocellular carcinoma ≤ 5 cm: a retrospective study.

Background/Objective: Treatment of hepatocellular carcinoma (HCC) with ablation alone often results in high rates of recurrence and metastasis, reaching up to 25.9% within two years. Therefore, this study aimed to examine the efficacy and safety of transarterial chemoembolization (TACE)-assisted multi-image guided radiofrequency ablation (RFA) for the treatment of stage Ia HCC according to the China liver cancer staging (CNLC). Methods: This study enrolled and analyzed a total of 118 patients diagnosed with HCC, each with a single nodular lesion no larger than 5 cm, who received TACE-RFA as first-line therapy between February 1, 2014, and December 31, 2021. The median/mean follow-up period was 29.0 months [95% confidence interval (CI): 21.8-36.2 months] and 31.8 months (95% CI: 27.5-36.0 months), respectively. We assessed the treatment's effectiveness, potential complications, and survival rate. Results: The technical success rate was 100% (118/118) after the initial treatment. Out of the total, 3 out of 118 patients (2.5%) developed local tumor progression (LTP) during the follow-up period. The median time for LTP was 29.0 months (95%CI: 21.9-36.1 months; mean: 31.5 months; range 1-92 months). At 1, 3, 5, and 7 years after treatment, the cumulative LTP rates were 0%, 4.6%, 4.6%, and 4.6%, respectively. The overall survival rates at 1, 3, 5, and 7 years were 100%, 95.2%, 95.2%, and 95.2%, respectively. In total, 28 patients experienced minor Grade B complications, and no major complications or treatment-related mortality occurred. Conclusion: The treatment of CNLC stage Ia HCC using TACE-assisted multi-image-guided RFA was found to be both safe and feasible.

Phytoalexin sakuranetin attenuates endocytosis and enhances resistance to rice blast.

Phytoalexin sakuranetin functions in resistance against rice blast. However, the mechanisms underlying the effects of sakuranetin remains elusive. Here, we report that rice lines expressing resistance (R) genes were found to contain high levels of sakuranetin, which correlates with attenuated endocytic trafficking of plasma membrane (PM) proteins. Exogenous and endogenous sakuranetin attenuates the endocytosis of various PM proteins and the fungal effector PWL2. Moreover, accumulation of the avirulence protein AvrCO39, resulting from uptake into rice cells by Magnaporthe oryzae, was reduced following treatment with sakuranetin. Pharmacological manipulation of clathrin-mediated endocytic (CME) suggests that this pathway is targeted by sakuranetin. Indeed, attenuation of CME by sakuranetin is sufficient to convey resistance against rice blast. Our data reveals a mechanism of rice against M. oryzae by increasing sakuranetin levels and repressing the CME of pathogen effectors, which is distinct from the action of many R genes that mainly function by modulating transcription.

Differences in fractional amplitude of low-frequency fluctuations (fALFF) and cognitive function between untreated major depressive disorder and schizophrenia with depressive mood patients.

BACKGROUND: Distinguishing untreated major depressive disorder without medication (MDD) from schizophrenia with depressed mood (SZDM) poses a clinical challenge. This study aims to investigate differences in fractional amplitude of low-frequency fluctuations (fALFF) and cognition in untreated MDD and SZDM patients. METHODS: The study included 42 untreated MDD cases, 30 SZDM patients, and 46 healthy controls (HC). Cognitive assessment utilized the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Resting-state functional magnetic resonance imaging (rs-fMRI) scans were conducted, and data were processed using fALFF in slow-4 and slow-5 bands. RESULTS: Significant fALFF changes were observed in four brain regions across MDD, SZDM, and HC groups for both slow-4 and slow-5 fALFF. Compared to SZDM, the MDD group showed increased slow-5 fALFF in the right gyrus rectus (RGR). Relative to HC, SZDM exhibited decreased slow-5 fALFF in the left gyrus rectus (LGR) and increased slow-5 fALFF in the right putamen. Changes in slow-5 fALFF in both RGR and LGR were negatively correlated with RBANS scores. No significant correlations were found between remaining fALFF (slow-4 and slow-5 bands) and RBANS scores in MDD or SZDM groups. CONCLUSIONS: Alterations in slow-5 fALFF in RGR may serve as potential biomarkers for distinguishing MDD from SZDM, providing preliminary insights into the neural mechanisms of cognitive function in schizophrenia.

[Effects of Different Modifiers on Aggregates and Organic Carbon in Acidic Purple Soil].

The aim of this study was to examine the effects of different modifiers on the changes in aggregates and organic carbon in acidic purple soil， providing a scientific basis for the remediation of acidic purple soil. Using purple soil as the research object， a total of six treatments were set up， including no fertilization （CK）， single fertilization （F）， fertilization with lime （SF）， fertilization with organic fertilizer （OM）， fertilization with biochar （BF）， and fertilization with distiller's grains ash （JZ）. We compared the composition of aggregates in acidic purple soil under the application of different modifiers， as well as the distribution pattern of organic carbon in aggregates of different particle sizes. Combined with the stability indicators of aggregates， we sought to clarify the impact of different modifiers on the structure of aggregates in acidic purple soil. The results showed that fertilization significantly increased the soil pH， with the JZ treatment being the most effective. Fertilization significantly increased soil organic matter content， with the OM treatment showing the largest increase. The BF and OM treatments significantly reduced soil bulk density， whereas the SF and BF treatments significantly increased soil moisture content （P < 0.05）. All treatments used < 0.25 mm aggregates as the dominant particle size. Fertilization could significantly increase the content of large aggregates （aggregate structure units with diameter > 0.25 mm）. At the same time， fertilization treatments significantly increased the soil geometric mean diameter （GMD）， average weight diameter （MWD）， and R0.25 value （ > 0.25 mm aggregate content） and reduced the fractal cone number （D） and aggregate destruction rate （PAD） values （P < 0.05）. Fertilization also promoted the aggregation and stability of soil aggregates， with the OM treatment having the greatest effect. Compared with that in the CK treatment， fertilization could significantly increase soil organic carbon content by 31.71%-209.67%， with the OM treatment showing the most significant change. Different treatments of soil organic carbon were mainly distributed in large aggregates. Compared with that in the CK treatment， each treatment significantly increased the contribution rate of organic carbon in large aggregates by 19.34%-47.76%， with the OM treatment having the most significant effect （P < 0.05）. In general， chemical fertilizer combined with organic fertilizer could promote the formation of large aggregates in acidic purple soil， improve the stability of soil aggregates， and increase the content of soil organic carbon， which is an effective measure to improve the soil structure and improve the quality of acidic purple soil.

Pseudomonas weihenstephanensis through the iron metabolism pathway promotes in situ spoilage capacity of prepared beef steaks during cold storage.

In this study, we evaluated the histomorphology, reactive oxygen species (ROS), protein degradation, and iron metabolism characteristics and differential expression analysis of genes for siderophores synthesis and protease secretion in prepared beef steaks inoculated alone or co-inoculated with P. weihenstephanensis, B. thermotrichothrix and M. caseolyticus at 4 °C for 12 days. The results showed that the P. weihenstephanensis was the key bacteria that degraded protein in the process of prepared beef steaks spoilage, which led to protein oxidation by promoting ferritin degradation to release free iron and inducing ROS accumulation. The highest expression of FpvA and AprE was detected in the P. weihenstephanensis group by comparing qRT-PCR of the different inoculation groups. Both qRT-PCR and Western blot revealed that ferritin heavy polypeptide and ferritin light chain polypeptide gene and protein expressions were significantly higher in the P. weihenstephanensis inoculation group compared to the other inoculation groups. Results suggested that FpvA and AprE might play roles in meat spoilage and were potential positional, physiological and functional candidate genes for improving the quality traits of prepared beef steaks. This work may provide insights on controlling food quality and safety by intervening in spoilage pathways targeting iron carrier biosynthesis or protease secretion genes.