ABSTRACT
Chemical redundancy of microbial natural products (NPs) underscores the importance to exploit new resources of microorganisms. Insect-associated microbes are prolific but largely underexplored sources of diverse NPs. Herein, we discovered the new compound α-l-rhamnosyl-actiphenol (1) from a millipede-associated Streptomyces sp. ML6, which is the first glycosylated cycloheximide-class natural product. Interestingly, bioinformatics analysis of the ML6 genome revealed that the biosynthesis of 1 involves a cooperation between two gene clusters (chx and rml) located distantly on the genome of ML6. We also carried out in vitro enzymatic glycosylation of cycloheximide using an exotic promiscuous glycosyltransferase BsGT-1, which resulted in the production of an additional cycloheximide glycoside cycloheximide 7-O-ß-d-glucoside (5). Although the antifungal and cytotoxic activities of the new compounds 1 and 5 were attenuated relative to those of cycloheximide, our work not only enriches the chemical repertoire of the cycloheximide family but also provides new insights into the structure-activity relationship optimization and ecological roles of cycloheximide.
Subject(s)
Actinobacteria , Glycosylation , Cycloheximide , Actinobacteria/metabolism , Glycosyltransferases/genetics , Glycosyltransferases/metabolism , GlycosidesABSTRACT
The Arabidopsis gene RESISTANCE TO POWDERY MILDEW8.1 (RPW8.1) confers resistance to virulent fungal and oomycete pathogens that cause powdery mildew and downy mildew, respectively. However, the underlying mechanism remains unclear. Here, we show that ectopic expression of RPW8.1 boosts pattern-triggered immunity (PTI) resulting in enhanced resistance against different pathogens in both Arabidopsis and rice. In Arabidopsis, transcriptome analysis revealed that ectopic expression of RPW8.1-YFP constitutively up-regulates expression of many pathogen-associated molecular pattern (PAMP-)-inducible genes. Consistently, upon PAMP application, the transgenic line expressing RPW8.1-YFP exhibited more pronounced PTI responses such as callose deposition, production of reactive oxygen species, expression of defence-related genes and hypersensitive response-like cell death. Accordingly, the growth of a virulent bacterial pathogen was significantly inhibited in the transgenic lines expressing RPW8.1-YFP. Conversely, impairment of the PTI signalling pathway from PAMP cognition to the immediate downstream relay of phosphorylation abolished or significantly compromised RPW8.1-boosted PTI responses. In rice, heterologous expression of RPW8.1-YFP also led to enhanced resistance to the blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae) and the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). Taken together, our data suggest a surprising mechanistic connection between RPW8.1 function and PTI, and demonstrate the potential of RPW8.1 as a transgene for engineering disease resistance across wide taxonomic lineages of plants.
Subject(s)
Arabidopsis/immunology , Arabidopsis/metabolism , Oryza/immunology , Oryza/metabolism , Plant Immunity/physiology , Plant Proteins/metabolism , Arabidopsis/genetics , Oryza/genetics , Plant Diseases/microbiology , Plant Immunity/genetics , Plant Proteins/genetics , Xanthomonas/immunology , Xanthomonas/pathogenicityABSTRACT
AIM: The inhaled anesthetic sevoflurane may induce cognitive impairment in both animals and humans. Previous study has shown that sevoflurane triggers ER stress and may lead to apoptosis in rat hippocampal neurons. In this study, we examined whether sevoflurane caused autophagy and its contributions to sevoflurane induced neuronal cell injury. METHODS: H4 human neuroglioma cells were exposed to 4.1% sevoflurane for 6 h. Cell viability and apoptosis ratio were assessed using a CCK8 kit and flow cytometry, respectively. Autophagosomes in the cells were detected using GFP-LC3 plasmid transfection or transmission electronic microscopy. The expression of LC3B, p62/SQSTM, C/EBP homologous protein (CHOP) and glucose-related protein 78 (GRP78) was assessed with Western blotting. RESULTS: Sevoflurane treatment induced apoptosis and markedly increased the LC3-II level and GFP-LC3 puncta number, decreased p62 expression in H4 cells. Activation of autophagy by rapamycin (1 µmol/L) significantly reduced sevoflurane-induced apoptosis and increased cell viability, whereas inhibition of autophagy with 3-MA (5 mmol/L) caused the opposite effects. Furthermore, sevoflurane treatment markedly increased the expression of CHOP and GRP78, two hallmark proteins of ER stress. Inhibition of ER stress by 4-phenylbutyrate (500 µmol/L) abrogated sevoflurane-induced autophagy and apoptosis, and improved the viability. Moreover, sevoflurane-stimulated expression of CHOP and GRP78 was inhibited by rapamycin, but further enhanced by 3-MA. CONCLUSION: Sevoflurane treatment induces ER stress and activates autophagy, which antagonizes sevoflurane-induced apoptosis in H4 human neuroglioma cells. The results suggest that autophagy may be a potential therapeutic target in preventing sevoflurane-induced neurotoxicity.
Subject(s)
Anesthetics, Inhalation/toxicity , Autophagy/drug effects , Methyl Ethers/toxicity , Apoptosis/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Endoplasmic Reticulum Chaperone BiP , Endoplasmic Reticulum Stress/drug effects , Humans , Sevoflurane , Sirolimus/pharmacologyABSTRACT
Esophageal cancer is the seventh most common type of cancer and the sixth leading cause of cancer -related mortality worldwide. Endoscopic submucosal dissection (ESD) is widely used for the resection of early esophageal cancer. However, post-ESD esophageal stricture is a common long-term complication, which requires attention. Patients with post-ESD esophageal stricture often experience dysphagia and require multiple dilatations, which greatly affects their quality of life and increases healthcare costs. Therefore, to manage post-ESD esophageal stricture, researchers are actively exploring various strategies, such as pharmaceutical interventions, endoscopic balloon dilation, and esophageal stenting. Although steroids-based therapy has achieved some success, steroids can lead to complications such as osteoporosis and infection. Meanwhile, endoscopic balloon dilatation is effective in the short term, but is prone to recurrence and perforation. Additionally, esophageal stenting can alleviate the stricture, but is associated with discomfort during stenting and the complication of easy displacement also present challenges. Tissue engineering has evolved rapidly in recent years, and hydrogel materials have good biodegradability and biocompatibility. A novel type of polyglycolic acid (PGA) sheets has been found to be effective in preventing esophageal stricture after ESD, with the advantages of a simple operation and low complication rate. PGA membranes act as a biophysical barrier to cover the wound as well as facilitate the delivery of medications to promote wound repair and healing. However, there is still a lack of multicenter, large-sample randomized controlled clinical studies focused on the treatment of post-ESD esophageal strictures with PGA membrane, which will be a promising direction for future advancements in this field.
ABSTRACT
Background: Metabolic dysfunction-associated fatty liver disease (MAFLD) is a novel proposed concept that is being recognized worldwide. Both chronic hepatitis B (CHB) and MAFLD have been independently attributed to an increased risk of disease development to cirrhosis. However, it is still unclear whether MAFLD is associated with an increased risk of cirrhosis in CHB patients. Aim: This study aimed to analyze the impact of MAFLD on the risk of cirrhosis in CHB patients. Methods: In this retrospective cohort study, consecutive CHB patients with or without MAFLD were enrolled from January 1st, 2007, to May 1st, 2020, in Guangdong Provincial Hospital of Chinese Medicine. Inverse probability treatment weighting (IPTW) was performed to balance the covariates across groups. The weighted Kaplan-Meier analysis and Cox regression analysis were used to compare both groups for the risk of cirrhosis. Results: A total of 1223 CHB patients were included in this study during the median follow-up of 5.25 years; of these patients, 355 were CHB-MAFLD patients. After IPTW, the weighted Kaplan-Meier analysis showed that the weighted cumulative incidence of cirrhosis was significantly higher in patients with MAFLD than that in patients without MAFLD (12.6% versus 7.1%, P=0.015). In the weighted multivariate Cox analysis, coexisting MAFLD was related to an increased risk of cirrhosis [adjusted weighted hazard ratio (HR) 1.790; P =0.020]. Age (>40 years, adjusted weighted HR, 1.950; P=0.015), diabetes mellitus (adjusted weighted HR, 1.883; P=0.041), non-antiviral treatment (adjusted weighted HR, 2.037; P=0.013), and baseline serum HBV DNA levels (>2.4 log10 IU/mL, adjusted weighted HR, 1.756; P=0.045) were significant risk factors for cirrhosis. Conclusion: We found that MAFLD was associated with a higher risk of cirrhosis in CHB patients.
ABSTRACT
Purpose: Both metabolic dysfunction-associated fatty liver disease (MAFLD) and hepatitis B virus (HBV) are risk factors for hepatocellular carcinoma (HCC). Although concurrent MAFLD is common in patients with HBV-related HCC, whether MAFLD increases the risk of poor prognosis in patients with HBV-related HCC remains unclear. This study aimed to investigate the impact of MAFLD on prognosis in patients with HBV-related HCC. Patients and Methods: In this retrospective cohort study, 549 patients with HBV-related HCC were enrolled from January 2010 to April 2020 in Guangdong Provincial Hospital of Chinese Medicine, including 169 patients with MAFLD (MAFLD group) and 380 patients without MAFLD (Non-MAFLD group). Propensity score matching (PSM) analysis was performed to balance the baseline characteristics. Kaplan-Meier survival curves were performed to compare the prognosis between the two matched groups. A multivariate Cox proportional hazards model was used to determine the risk factors for poor prognosis. Results: The median follow-up time for all patients was 20 (interquartile range 8-40) months. We found concurrent MAFLD was associated with a significantly decreased PFS rate before and after PSM analysis. The 1-year, 2-year, and 3-year PFS rates for the MAFLD and Non-MAFLD groups after PSM were 61.3% and 70.8%, 43.9% and 54.5%, 31.1% and 41.8%, respectively. Cox multivariable analysis showed that concurrent MAFLD was an independent risk factor for poor prognosis (death or progression) (HR = 1.49, P = 0.001). More interestingly, the risk of poor prognosis was significantly higher in the MAFLD subtype with metabolic components ≥2 compared to those with metabolic components <2 (HR = 1.97, P < 0.001). Conclusion: Concurrent MAFLD was associated with a higher risk of poor prognosis in patients with HBV-related HCC, especially MAFLD with metabolic components ≥2.
ABSTRACT
Effects of different nitrogen application methods on microbial community structure of paddy soil at different rice growth stages were examined using phospholipid fatty acid analysis (PLFA) and Biolog technique. There were four treatments, no straw returning or fertilization (CK), straw returning +urea with the proportions of after wheat harvest, before rice transplanting, tillering stage and booting stage being 0:6:2:2 (T1) and 3:3:2:2 (T2), and straw returning+co-application of biogas slurry and urea with the proportion of after wheat harvest, before rice transplanting, tillering stage and booting stage being 3 (biogas slurry):3 (2biogas slurry+1urea):2 (urea):2 (urea)(T3). Results showed that T3 significantly increased soil available nitrogen contents at all growth stages, which was significantly higher at maturity stage than that at tillering and booting stages. T1-T3 had higher available phosphorus and available potassium contents at all growth stages compared with CK, which were higher at tillering stage than at booting and maturity stages. The interaction between growth stage and treatment in paddy soil significantly affected the contents of soil available nitrogen, available phosphorus and available potassium. Furthermore, carbohydrate, amino acid, polymer and carboxylic acid were the primary carbon sources for microbial community of paddy soil. T3 effectively enhanced soil carbon sources metabolic utilization intensity. The interaction between growth stage and treatment in paddy soil significantly affected the microbial utilization capacity of carbohydrates and carboxylic acids. Soil microbial biomass was significantly higher in T2 and T3 treatments. Moreover, T2 had high fungi/bacteria (F/B) value, indicating that fungi could benefit the stabilization of paddy soil. In summary, simultaneous nitrogen application (urea or biogas slurry) and straw returning could increase soil microbial activity and improve soil environment in paddy field.
Subject(s)
Microbiota , Oryza , Agriculture , Fertilizers , Nitrogen , Soil , Soil MicrobiologySubject(s)
Hypertension/mortality , Poverty/statistics & numerical data , Socioeconomic Factors , Adult , Aged , Aged, 80 and over , China/epidemiology , Female , Humans , Male , Middle Aged , Risk FactorsABSTRACT
Ophiocordyceps sinensis (Ascomycota: Ophiocordycipitaceae) is a native fungal parasite of Hepialidae caterpillars and one of the most economically important medicinal caterpillar fungi in China. However, little is known about the phylogenetic and evolutionary relationships between O. sinensis and its host insects. In this study, nuclear ITS and ß-tubulin sequences from O. sinensis and mitochondrial COI, COII, and Cytb sequences from its hosts were analyzed across 33 populations sampled from five regions in China. Phylogenetically, both O. sinensis and its hosts were divided into three geographically correlated clades, and their phylogenies were congruent. Analysis of molecular variance and calculated coefficients of genetic differentiation revealed significant genetic divergence among the clades within both O. sinensis (F(ST)= 0.878, N(ST)=0.842) and its hosts (F(ST)=0.861, N(ST)=0.816). Estimated gene flow was very low for O. sinensis (Nm=0.04) and the host insects (Nm=0.04) among these three clades. Mantel tests demonstrated a significant correlation (P<0.01) between the genetic distances for O. sinensis and its hosts, as well as a significant association (P<0.05) between geographic and genetic distances in both. The similar phylogenetic relationships, geographic distributions, and genetic structure and differentiation between O. sinensis and its hosts imply that they have coevolved.