Low-cost and efficient strategy for brown algal hydrolysis: Combination of alginate lyase and cellulase.

Brown algae are rich in biostimulants that not only stimulate the overall development and growth of plants but also have great beneficial effects on the whole soil-plant system. However, alginate, the major component of brown algae, is comparatively difficult to degrade. The cost of preparing alginate oligosaccharides (AOSs) is still too high to produce seaweed fertilizer. In this work, the marine bacterium Vibrio sp. B1Z05 is found to be capable of efficient alginate depolymerization and harbors an extended pathway for alginate metabolism. The B1Z05 extracellular cell-free supernatant exhibited great potential for AOS production at low cost, which, together with cellulase, can efficiently hydrolyze seaweed. The brown algal hydrolysis rates were significantly greater than those of the commercial alginate lyase product CE201, and the obtained seaweed extracts were rich in phytohormones. This work provides a low-cost but efficient strategy for the sustainable production of desirable AOSs and seaweed fertilizer.

The causal relationship between gut microbiota and leukemia: a two-sample Mendelian randomization study.

Background: The association between gut microbiota and leukemia has been established, but the causal relationship between the two remains unclear. Methods: A bidirectional two-sample Mendelian randomization (MR) was used to analyze the causal relationship between gut microbiota and leukemia. Microbiome data (n = 14,306) and leukemia (n = 1,145) data were both sourced from European populations. Single nucleotide polymorphisms (SNPs) were selected as instrumental variables based on several criteria. We employed various MR methods, such as the inverse variance weighted (IVW) method, to evaluate the causal effect between exposure and outcomes and conducted sensitivity analyses to validate the heterogeneity and pleiotropy of the instrumental variables. Results: 5,742 qualified instrumental variables were included. In the primary MR results, a total of 10 gut microbial taxa were associated with leukemia risk. Genus Blautia and genus Lactococcus are risk factors for acute lymphoblastic leukemia [genus Blautia odds ratio (OR): 1.643, 95% confidence interval (CI): 1.592 ~ 1.695, Adjusted p < 0.001; genus Lactococcus OR: 2.152, 95% CI: 1.447 ~ 3.199, Adjusted p = 0.011]. Genus Rikenellaceae RC9 gut group, genus Anaerostipes, genus Slackia, and genus Lachnospiraceae ND3007 group are risk factors for acute myeloid leukemia [genus Rikenellaceae RC9 gut group OR: 1.964, 95% CI: 1.573 ~ 2.453, Adjusted p < 0.001; genus Anaerostipes OR: 2.515, 95% CI: 1.503 ~ 4.209, Adjusted p = 0.017; genus Slackia OR: 2.553, 95% CI: 1.481 ~ 4.401, Adjusted p = 0.022; genus Lachnospiraceae ND3007 group OR: 3.417, 95% CI: 1.960 ~ 5.959, Adjusted p = 0.001]. Genus Ruminococcaceae UCG011 and genus Ruminococcaceae UCG014 were risk factors for chronic myeloid leukemia (genus Ruminococcaceae UCG011 OR: 2.010, 95% CI: 1.363 ~ 2.963, Adjusted p = 0.044; genus Ruminococcaceae UCG014 OR: 3.101, 95% CI: 1.626 ~ 5.915, Adjusted p = 0.044). Genus Slackia was a protective factor for acute lymphoblastic leukemia (genus Slackia OR: 0.166, 95% CI: 0.062 ~ 0.443, Adjusted p = 0.017). Family Acidaminococcaceae was a protective factor for acute myeloid leukemia (family Acidaminococcaceae OR: 0.208, 95% CI: 0.120 ~ 0.361, Adjusted p < 0.001). Genus Desulfovibrio was a protective factor for chronic lymphoblastic leukemia (genus Desulfovibrio OR: 0.581, 95% CI: 0.440 ~ 0.768, Adjusted p = 0.020). Sensitivity analysis revealed no heterogeneity or pleiotropy between SNPs. Conclusion: This study revealed the causal relationship between the gut microbiota and leukemia, and identified potential pathogenic bacteria and probiotic taxa associated with the onset of leukemia. This research may aid in the early detection of various types of leukemia and offer a new direction for the prevention and treatment of leukemia.

WGX50 mitigates doxorubicin-induced cardiotoxicity through inhibition of mitochondrial ROS and ferroptosis.

BACKGROUND: Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a major impediment to its clinical application. It is indispensable to explore alternative treatment molecules or drugs for mitigating DIC. WGX50, an organic extract derived from Zanthoxylum bungeanum Maxim, has anti-inflammatory and antioxidant biological activity, however, its function and mechanism in DIC remain unclear. METHODS: We established DOX-induced cardiotoxicity models both in vitro and in vivo. Echocardiography and histological analyses were used to determine the severity of cardiac injury in mice. The myocardial damage markers cTnT, CK-MB, ANP, BNP, and ferroptosis associated indicators Fe2+, MDA, and GPX4 were measured using ELISA, RT-qPCR, and western blot assays. The morphology of mitochondria was investigated with a transmission electron microscope. The levels of mitochondrial membrane potential, mitochondrial ROS, and lipid ROS were detected using JC-1, MitoSOX™, and C11-BODIPY 581/591 probes. RESULTS: Our findings demonstrate that WGX50 protects DOX-induced cardiotoxicity via restraining mitochondrial ROS and ferroptosis. In vivo, WGX50 effectively relieves doxorubicin-induced cardiac dysfunction, cardiac injury, fibrosis, mitochondrial damage, and redox imbalance. In vitro, WGX50 preserves mitochondrial function by reducing the level of mitochondrial membrane potential and increasing mitochondrial ATP production. Furthermore, WGX50 reduces iron accumulation and mitochondrial ROS, increases GPX4 expression, and regulates lipid metabolism to inhibit DOX-induced ferroptosis. CONCLUSION: Taken together, WGX50 protects DOX-induced cardiotoxicity via mitochondrial ROS and the ferroptosis pathway, which provides novel insights for WGX50 as a promising drug candidate for cardioprotection.

Corrigendum: Impact of intestinal microbiota on metabolic toxicity and potential detoxification of amygdalin.

[This corrects the article DOI: 10.3389/fmicb.2022.1030516.].

Phylogenetics and biomineralization of a novel magnetotactic Gammaproteobacterium from a freshwater lake in Beijing, China.

Magnetotactic bacteria (MTB) have the remarkable capability of producing intracellularly membrane-enveloped magnetic nanocrystals (i.e. magnetosomes) and swimming along geomagnetic field lines. Despite more than 50 years of research, bacterial diversity and magnetosome biomineralization within MTB are relatively less known in the Gammaproteobacteria class than other groups. This is incompatible with the status of Gammaproteobacteria as the most diverse class of gram-negative bacteria with a number of ecologically important bacteria. Here, we identify a novel MTB strain YYHR-1 affiliated with the Gammaproteobacteria class of the Pseudomonadota phylum from a freshwater lake. In YYHR-1, most magnetosome crystals are organized into a long chain aligned along the cell long axis; unusually, a few small superparamagnetic crystals are located at the side of the chain, off the main chain axis. Micromagnetic simulations indicate that magnetostatic interactions among adjacent crystals within a chain reduce the Gibbs energy to enhance chain stability. Genomic analysis suggests that duplication of magnetosome gene clusters may result in off-chain magnetosomes formation. By integrating available genomic data from Gammaproteobacteria, the phylogenetic position of MTB in this class is reassigned here. Our new findings expand knowledge about MTB diversity and magnetosome biomineralization, and deepen understanding of the phylogenetics of the Gammaproteobacteria.

A novel transcriptional repressor specifically regulates xylanase gene 1 in Trichoderma reesei.

BACKGROUND: The well-known industrial fungus Trichoderma reesei has an excellent capability of secreting a large amount of cellulases and xylanases. The induced expression of cellulase and xylanase genes is tightly controlled at the transcriptional level. However, compared to the intensive studies on the intricate regulatory mechanism of cellulase genes, efforts to understand how xylanase genes are regulated are relatively limited, which impedes the further improvement of xylanase production by T. reesei via rational strain engineering. RESULTS: To identify transcription factors involved in regulating xylanase gene expression in T. reesei, yeast one-hybrid screen was performed based on the promoters of two major extracellular xylanase genes xyn1 and xyn2. A putative transcription factor named XTR1 showing significant binding capability to the xyn1 promoter but not that of xyn2, was successfully isolated. Deletion of xtr1 significantly increased the transcriptional level of xyn1, but only exerted a minor promoting effect on that of xyn2. The xylanase activity was increased by ~ 50% with XTR1 elimination but the cellulase activity was hardly affected. Subcellular localization analysis of XTR1 fused to a green fluorescence protein demonstrated that XTR1 is a nuclear protein. Further analyses revealed the precise binding site of XTR1 and nucleotides critical for the binding within the xyn1 promoter. Moreover, competitive EMSAs indicated that XTR1 competes with the essential transactivator XYR1 for binding to the xyn1 promoter. CONCLUSIONS: XTR1 represents a new transcriptional repressor specific for controlling xylanase gene expression. Isolation and functional characterization of this new factor not only contribute to further understanding the stringent regulatory network of xylanase genes, but also provide important clues for boosting xylanase biosynthesis in T. reesei.

Hydrogen-Bonded Organic Frameworks Chelated Manganese for Precise Magnetic Resonance Imaging Diagnosis of Cancers.

Magnetic resonance imaging (MRI) is an important tool in the diagnosis of many cancers. However, clinical gadolinium (Gd)-based MRI contrast agents have limitations, such as large doses and potential side effects. To address these issues, we developed a hydrogen-bonded organic framework-based MRI contrast agent (PFC-73-Mn). Due to the hydrogen-bonded interaction of water molecules and the restricted rotation of manganese ions, PFC-73-Mn exhibits high longitudinal relaxation r1 (5.03 mM-1 s-1) under a 3.0 T clinical MRI scanner. A smaller intravenous dose (8 µmol of Mn/kg) of PFC-73-Mn can provide strong contrast and accurate diagnosis in multiple kinds of cancers, including breast tumor and ultrasmall orthotopic glioma. PFC-73-Mn represents a prospective new approach in tumor imaging, especially in early-stage cancer.

Short-chain fatty acids (SCFAs) as potential resuscitation factors that promote the isolation and culture of uncultured bacteria in marine sediments.

Many marine bacteria are difficult to culture because they are dormant, rare or found in low-abundances. Enrichment culturing has been widely tested as an important strategy to isolate rare or dormant microbes. However, many more mechanisms remain uncertain. Here, based on 16S rRNA gene high-throughput sequencing and metabolomics technology, it was found that the short-chain fatty acids (SCFAs) in metabolites were significantly correlated with uncultured bacterial groups during enrichment cultures. A pure culture analysis showed that the addition of SCFAs to media also resulted in high efficiency for the isolation of uncultured strains from marine sediments. As a result, 238 strains belonging to 10 phyla, 26 families and 82 species were successfully isolated. Some uncultured rare taxa within Chlorobi and Kiritimatiellaeota were successfully cultured. Amongst the newly isolated uncultured microbes, most genomes, e.g. bacteria, possess SCFA oxidative degradation genes, and these features might aid these microbes in better adapting to the culture media. A further resuscitation analysis of a viable but non-culturable (VBNC) Marinilabiliales strain verified that the addition of SCFAs could break the dormancy of Marinilabiliales in 5 days, and the growth curve test showed that the SCFAs could shorten the lag phase and increase the growth rate. Overall, this study provides new insights into SCFAs, which were first studied as resuscitation factors in uncultured marine bacteria. Thus, this study can help improve the utilisation and excavation of marine microbial resources, especially for the most-wanted or key players. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00187-w.

Tetrahedral Bonding Structure (Ni3 -Se) Induced by Lattice-Distortion of Ni to Achieve High Catalytic Activity in Na-Se Battery.

Fabrication of transition-metal catalytic materials is regarded as a promising strategy for developing high-performance sodium-selenium (Na-Se) batteries. However, more systematic explorations are further demanded to find out how their bonding interactions and electronic structures can affect the Na storage process. This study finds that lattice-distorted nickel (Ni) structure can form different bonding structures with Na2 Se4 , providing high activity to catalyze the electrochemical reactions in Na-Se batteries. Using this Ni structure to prepare electrode (Se@NiSe2 /Ni/CTs) can realize rapid charge transfer and high cycle stability of the battery. The electrode exhibits high storage performance of Na+ ; i.e., 345 mAh g⁻1 at 1 C after 400 cycles, and 286.4 mAh g⁻1 at 10 C in rate performance test. Further results reveal the existence of a regulated electronic structure with upshifts of the d-band center in the distorted Ni structure. This regulation changes the interaction between Ni and Na2 Se4 to form a Ni3 -Se tetrahedral bonding structure. This bonding structure can provide higher adsorption energy of Ni to Na2 Se4 to facilitate the redox reaction of Na2 Se4 during the electrochemical process. This study can inspire the design of bonding structure with high performance in conversion-reaction-based batteries.

Construction of the novel immune risk scoring system related to CD8+ T cells in uterine corpus endometrial carcinoma.

BACKGROUND: Uterine corpus endometrial carcinoma (UCEC) is a gynecological malignant tumor with high incidence and poor prognosis. Although immunotherapy has brought significant survival benefits to advanced UCEC patients, traditional evaluation indicators cannot accurately identify all potential beneficiaries of immunotherapy. Consequently, it is necessary to construct a new scoring system to predict patient prognosis and responsiveness of immunotherapy. METHODS: CIBERSORT combined with weighted gene co-expression network analysis (WGCNA), non-negative matrix factorization (NMF), and random forest algorithms to screen the module associated with CD8+ T cells, and key genes related to prognosis were selected out by univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analyses to develop the novel immune risk score (NIRS). Kaplan-Meier (K-M) analysis was used to compare the difference of survival between high- and low- NIRS groups. We  also explored the correlations between NIRS, immune infiltration and immunotherapy, and three external validation sets were used to verify the predictive performance of NIRS. Furthermore, clinical subgroup analysis, mutation analysis, differential expression of immune checkpoints, and drug sensitivity analysis were performed to generate individualized treatments for patients with different risk scores. Finally, gene set variation analysis (GSVA) was conducted to explore the biological functions of NIRS, and qRT-PCR was applied to verify the differential expressions of three trait genes at cellular and tissue levels. RESULTS: Among the modules clustered by WGCNA, the magenta module was most positively associated with CD8+ T cells. Three genes (CTSW, CD3D and CD48) were selected to construct NIRS after multiple screening procedures. NIRS was confirmed as an independent prognostic factor of UCEC, and patients with high NIRS had significantly worse prognosis compared to those with low NIRS. The high NIRS group showed lower levels of infiltrated immune cells, gene mutations, and expression of multiple immune checkpoints, indicating reduced sensitivity to immunotherapy. Three module genes were identified as protective factors positively correlated with the level of CD8+ T cells. CONCLUSIONS: In this study, we constructed NIRS as a novel predictive signature of UCEC. NIRS not only differentiates patients with distinct prognoses and immune responsiveness, but also guides their therapeutic regimens.

Association of Long Noncoding RNA Expression Signatures with Stress-Induced Myocardial Perfusion Defects.

Stress-induced myocardial perfusion defects found in dipyridamole-thallium-201 single-photon emission computed tomography imaging may indicate vascular perfusion abnormalities and risk of obstructive or nonobstructive coronary heart disease. Besides nuclear imaging and subsequent coronary angiography (CAG), no blood test can indicate whether dysregulated homeostasis is associated with stress-induced myocardial perfusion defects. This study investigated the expression signature of long noncoding RNAs (lncRNAs) and genes involved in vascular inflammation and stress response in the blood of patients with stress-induced myocardial perfusion abnormalities (n = 27). The results revealed an expression signature consisting of the upregulation of RMRP (p < 0.01) and downregulations of THRIL (p < 0.01) and HIF1A (p < 0.01) among patients with a positive thallium stress test and no significant coronary artery stenosis within 6 months after baseline treatment. We developed a scoring system based on the expression signatures of RMRP, MIAT, NTT, MALAT1, HSPA1A, and NLRP3 to predict the need for further CAG among patients with moderate-to-significant stress-induced myocardial perfusion defects (area under the receiver operating characteristic curve = 0.963). Therefore, we identified a dysregulated expression profile of lncRNA-based genes in the blood that could be valuable for the early detection of vascular homeostasis imbalance and personalized therapy.

Magnetic Resonance Diagnosis of Early Triple-Negative Breast Cancer Based on the Ionic Covalent Organic Framework with High Relaxivity and Long Retention Time.

Patients with triple-negative breast cancer (TNBC) have dismal prognoses due to the lack of therapeutic targets and susceptibility to lymph node (LN) metastasis. Therefore, it is essential to develop more effective approaches to identify early TNBC tissues and LNs. In this work, a magnetic resonance imaging (MRI) contrast agent (Mn-iCOF) was constructed based on the Mn(II)-chelated ionic covalent organic framework (iCOF). Because of the porous structure and hydrophilicity, the Mn-iCOF has a high longitudinal relaxivity (r1) of 8.02 mM-1 s-1 at 3.0 T. For the tumor-bearing mice, a lower dose (0.02 mmol [Mn]/kg) of Mn-iCOF demonstrated a higher signal-to-noise ratio (SNR) value (1.8) and longer retention time (2 h) compared to a 10-fold dose of commercial Gd-DOTA (0.2 mmol [Gd]/kg). Moreover, the Mn-iCOF can provide continuous and significant MR contrast for the popliteal LNs within 24 h, allowing for accurate evaluation and dissection of LNs. These excellent MRI properties of the Mn-iCOF may open new avenues for designing more biocompatible MRI contrast agents with higher resolutions, particularly in the diagnosis of TNBC.

Construction of a novel molecular typing and scoring system for anoikis distinguishes between different prognostic risks and treatment responsiveness in low-grade glioma.

Background: The main factors responsible for low-grade glioma (LGG)s' poor prognosis and treatment effectiveness include recurrence and malignant progression. A specific type of programmed cell death, known as anoikis, which is crucial for tumor invasion and metastasis, however, has not yet been investigated in LGGs. Methods: We downloaded data of 509 samples from the TCGA-LGG cohort, carried out cluster analysis for typing twice on the basis of 19 anoikis-associated genes, and the subtypes were evaluated the differences in clinicopathological and biological features. ESTIMATE and single-sample gene set enrichment analysis were employed to examine the immunological milieu of LGGs, and enrichment analysis was used to look into the underlying biological mechanisms in LGGs. Cox regression analysis and the Least Absolute Shrinkage and Selection Operator regression algorithm were used to create a prediction scoring system. The scoring system was used for classifying LGG into high- and low- anoikis riskscore (anoiS) groups. The impact of the anoiS on the prognosis, standard treatment, and immunotherapy of patients with LGG was assessed using survival analysis and drug sensitivity analysis. Cell experiments were employed for the verification of the differential expression between LGG cells and normal cells of the anoikis gene team that regard CCT5 as the core. Results: Based on the expression profiles of the 19 anoikis-associated genes, all individuals with LGG were classified into four subtypes and two macrosubtypes. The different macrosubtypes had significantly different biological characteristics, and the anoirgclusterBD subtype manifested a significantly bad prognosis and a high immune level of infiltration. And subsequent secondary genotyping also showed good prognostic discrimination. We further constructed an anoikis scoring system, anoiS. LGG patients having a high anoiS had a worse prognosis in comparison to those having a low anoiS. The high anoiS group exhibited larger levels of immune infiltration and superior immunotherapy efficacy than the low anoiS group. The high anoiS group was also more susceptible to temozolomide (TMZ) than the low anoiS group, according to a drug sensitivity analysis of TMZ. Conclusion: This study constructed a scoring system for predicting the prognosis of patients with LGG and their responsive to TMZ and immunotherapy.

Niche Modification by Sulfate-Reducing Bacteria Drives Microbial Community Assembly in Anoxic Marine Sediments.

Sulfate-reducing bacteria (SRB) are essential functional microbial taxa for degrading organic matter (OM) in anoxic marine environments. However, there are little experimental data regarding how SRB regulates microbial communities. Here, we applied a top-down microbial community management approach by inhibiting SRB to elucidate their contributions to the microbial community during OM degradation. Based on the highly replicated microcosms (n = 20) of five different incubation stages, we found that many microbial community properties were influenced after inhibiting SRB, including the composition, structure, network, and community assembly processes. We also found a strong coexistence pattern between SRB and other abundant phylogenetic lineages via positive frequency-dependent selection. The relative abundances of the families Synergistaceae, Peptostreptococcaceae, Dethiosulfatibacteraceae, Prolixibacteraceae, Marinilabiliaceae, and Marinifilaceae were simultaneously suppressed after inhibiting SRB during OM degradation. A close association between SRB and the order Marinilabiliales among coexisting taxa was most prominent. They contributed to preserved modules during network successions, were keystone nodes mediating the networked community, and contributed to homogeneous ecological selection. The molybdate tolerance test of the isolated strains of Marinilabiliales showed that inhibited SRB (not the inhibitor of SRB itself) triggered a decrease in the relative abundance of Marinilabiliales. We also found that inhibiting SRB resulted in reduced pH, which is unsuitable for the growth of most Marinilabiliales strains, while the addition of pH buffer (HEPES) in SRB-inhibited treatment microcosms restored the pH and the relative abundances of these bacteria. These data supported that SRB could modify niches to affect species coexistence. IMPORTANCE Our model offers insight into the ecological properties of SRB and identifies a previously undocumented dimension of OM degradation. This targeted inhibition approach could provide a novel framework for illustrating how functional microbial taxa associate the composition and structure of the microbial community, molecular ecological network, and community assembly processes. These findings emphasize the importance of SRB during OM degradation. Our results proved the feasibility of the proposed study framework, inhibiting functional taxa at the community level, for illustrating when and to what extent functional taxa can contribute to ecosystem services.

Simultaneous determination of serum tryptophan metabolites in an older Chinese population.

Tryptophan (TRP) and its metabolites exhibit significant biological effects and are strongly associated with age-related disease and mortality. However, reports on quantitatively analyzing these metabolites in older individuals are not available. We used ultra-high-performance liquid chromatography-tandem mass spectrometry to optimize and validate a method for isotope dilution analysis of TRP metabolites in older individuals. The targeted analytes are TRP, serotonin or 5-hydroxytryptamine, kynurenine, kynurenic acid, xanthurenic acid, indole-3-acetic acid, indole-3-propionic acid, and tryptamine. The serum sample was purified using solid-phase extraction and was separated on a Waters HSS T3 column (100 mm × 2.1 mm, 1.8 µm). The analytes were detected in the multiple reaction monitoring mode under positive ionization. TRP was confirmed and measured after being diluted 100 times. This method exhibited satisfactory linearity (r > 0.99). The intrabatch and interbatch accuracies (85.7-114%) and precisions (<15%) were acceptable. The standard-normalized matrix effects ranged from 51.6 to 145%. This method was successfully applied to a cohort of 1021 older Chinese individuals, and this study may enable further understanding of the metabolic phenotypes associated with TRP in other populations.

Impact of intestinal microbiota on metabolic toxicity and potential detoxification of amygdalin.

Amygdalin (Amy) is metabolized into cyanide in vivo, which may lead to fatal poisoning after oral administration. The defense mechanisms against toxic cyanide have not yet been adequately studied. In this study, comparative toxicokinetics study of Amy was performed in normal and pseudo germ-free rats. The efficiency of cyanide release was significant higher in normal group when given a single oral dose of 440 mg/kg (50% median lethal dose). Thiocyanate, the detoxification metabolite, was firstly detected in feces, caecum, and intestinal microbiota incubation enzymic system. The results suggest intestinal microbiota is involved in bidirectional regulation of toxicity and detoxification of Amy. We further identified the species related to cyanogenesis of Amy with metagenomic sequencing, such as Bifidobacterium pseudolongum, Marvinbryantia formatexigens, and Bacteroides fragilis. Functional analysis of microbiota reveals the detoxification potential of intestinal microbiota for cyanide. Sulfurtransferase superfamily, such as rhodanese, considered as main detoxification enzymes for cyanide, are largely found in Coriobacteriaceae bacterium, Butyricicoccus porcorum, Akkermansia muciniphila, etc. Besides, cyanoamino acid metabolism pathway dominated by Escherichia coli may contribute to the detoxification metabolism of cyanide. In summary, intestinal microbiota may be the first line of defense against the toxicity induced by Amy.

Integrated assessment of the clinical and biological value of ferroptosis-related genes in multiple myeloma.

BACKGROUND: Ferroptosis is an iron-dependent mode of cell death that could be induced by erastin and exert antitumor effects. However, the clinical and biological roles of ferroptosis-related gene (FRG) signature and the therapeutic value of erastin in multiple myeloma (MM) remained unknown. METHODS: Clinical and gene expression data of MM subjects were extracted from the Gene Expression Omnibus (GEO) public database. Univariable cox analysis was applied to determine FRGs related to survival and the least absolute shrinkage and selection operator (LASSO) regression analysis was used to develop a prognostic model. Prediction accuracy of the model was estimated by receiver operating characteristic (ROC) curves. Functional pathway enrichments and infiltrating immune status were also analyzed. We conducted in vitro experiments to investigate the combination therapy of erastin and doxorubicin. RESULTS: 17 FRGs were strongly associated with patient survival and 11 genes were identified to construct the prognostic model. ROC curves indicated great predictive sensitivity and specificity of the model in all cohorts. Patients were divided into low- and high-risk groups by median risk score in each cohort and the survival of the low-risk group was significantly superior than that of the high-risk group. We also observed a close relevance between functional pathways and immune infiltration with risk scores. Moreover, we combined erastin and doxorubicin in our in vitro experiments and found synergetic antitumor effects of the two agents, and the underlying mechanism is the overgeneration of intracellular Reactive Oxygen Species (ROS). CONCLUSIONS: We demonstrated the important value of ferroptosis in patient prognosis and as a potential antitumor target for MM.

CircKIF4A Is a Prognostic Factor and Modulator of Natural Killer/T-Cell Lymphoma Progression.

Background: Natural killer/T-cell lymphoma (NKTL) is difficult to treat. Circular RNAs (circ RNAs) have been implicated in tumorigenesis. However, the function of circKIF4A in NKTL has not been investigated. Methods: QPCR analysis was used to compare circKIF4A levels in NKTL cell lines versus normal cell lines. Kaplan-Meier survival analysis was used to assess the effect of circKIF4A on the prognosis of NKTL. The correlation between clinicopathological features and circKIF4A expression was examined using cox regression analysis. Luciferase reporter, RNA immunoprecipitation and immunohistochemistry assays were also used to investigate the mechanisms of circKIF4A in NKTL. Results: Our analyses revealed that circKIF4A is significantly upregulated in NKTL cell lines and that its upregulation correlates with the poor prognosis of NKTL. The silencing of circKIF4A significantly suppressed glucose uptake and lactate production in NKTL cells. Moreover, we showed that circKIF4A, PDK1, and BCL11A bind miR-1231 and that circKIF4A regulates PDK1 and BCL11A expressions by sponging miR-1231. Conclusions: During NKTL progression, circKIF4A regulated PDK1 and BCL11A levels by sponging miR-1231. Our data indicated that circKIF4A is oncogenic in NKTL and that it is a predictor of poor prognosis of NKTL.

Characterization of the (Engineered) Branching Sucrase GtfZ-CD2 from Apilactobacillus kunkeei for Efficient Glucosylation of Benzenediol Compounds.

Branching sucrases, a subfamily of Glycoside Hydrolase family (GH70), display transglycosidase activity using sucrose as donor substrate to catalyze glucosylation reaction in the presence of suitable acceptor substrates. In this study, the (α1→3) branching sucrase GtfZ-CD2 from Apilactobacillus kunkeei DSM 12361 was demonstrated to glucosylate benzenediol compounds (i.e., catechol, resorcinol, and hydroquinone) to form monoglucoside and diglucoside products. The production and yield of catechol glucosylated products were significantly higher than that of resorcinol and hydroquinone, revealing a preference for adjacent aromatic hydroxyl groups in glucosylation. Amino residues around acceptor substrate binding subsite +1 were targeted for semirational mutagenesis, yielding GtfZ-CD2 variants with improved resorcinol and hydroquinone glucosylation. Mutant L1560Y with improved hydroquinone mono-glucosylated product synthesis allowed enzymatic conversion of hydroquinone into α-arbutin. This study thus revealed the high potential of GH70 branching sucrases for glucosylating noncarbohydrate molecules. IMPORTANCE Glycosylation represents one of the most important ways to expand the diversity of natural products and improve their physico-chemical properties. Aromatic polyphenol compounds widely found in plants are reported to exhibit various remarkable biological activities; however, they generally suffer from low solubility and stability, which can be improved by glycosylation. Our present study on the glucosylation of benzenediol compounds by GH70 branching sucrase GtfZ-CD2 and its semirational engineering to improve the glucosylation efficiency provides insight into the mechanism of acceptor substrates binding and its glucosylation selectivity. The results demonstrate the potential of using branching sucrase as an effective enzymatic glucosylation tool.

Intestinal microbiota-mediated biotransformations alter the pharmacokinetics of the major metabolites of azathioprine in rats after oral administration.

Adverse reactions to azathioprine (AZA) vary greatly among individuals, which is associated with the variable levels of its major metabolites 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP). The intestinal microbiota has been proven to contain AZA-metabolizing enzymes, although the explicit role of the intestinal microbiota in AZA metabolism in vivo remains poorly comprehended. In this study, the pharmacokinetic behaviours of 6-TGN and 6-MMP were assessed in the pseudo germ-free (PGF) group and control group following oral administration of AZA. The AUC0-t and Cmax of 6-TGN in the PGF group were significantly decreased by 34.0% and 35.0% (P < 0.05) compared with those in the control group. Additionally, the AUC0-t and Cmax of 6-MMP were reduced by 27.9% and 34.2% in the PGF group, although the differences were not significant. The TPMT and NUDT15 genotypes of rats in the two groups were genetically identical. The expression levels of key AZA-metabolizing enzymes in liver were not different between two groups. Furthermore, the major metabolites of AZA in the incubation system with intestinal microbial enzymes were identified. In summary, shifts in the composition of the intestinal microbiota may regulate the exposure of 6-TGN in vivo by altering the gut microbial metabolism of AZA.