Identifying thresholds of nitrogen enrichment for substantial shifts in arbuscular mycorrhizal fungal community metrics in a temperate grassland of northern China.

Nitrogen (N) enrichment poses threats to biodiversity and ecosystem stability, while arbuscular mycorrhizal (AM) fungi play important roles in ecosystem stability and functioning. However, the ecological impacts, especially thresholds of N enrichment potentially causing AM fungal community shifts have not been adequately characterized. Based on a long-term field experiment with nine N addition levels ranging from 0 to 50 g N m-2 yr-1 in a temperate grassland, we characterized the community response patterns of AM fungi to N enrichment. Arbuscular mycorrhizal fungal biomass continuously decreased with increasing N addition levels. However, AM fungal diversity did not significantly change below 20 g N m-2 yr-1 , but dramatically decreased at higher N levels, which drove the AM fungal community to a potentially unstable state. Structural equation modeling showed that the decline in AM fungal biomass could be well explained by soil acidification, whereas key driving factors for AM fungal diversity shifted from soil nitrogen : phosphorus (N : P) ratio to soil pH with increasing N levels. Different aspects of AM fungal communities (biomass, diversity and community composition) respond differently to increasing N addition levels. Thresholds for substantial community shifts in response to N enrichment in this grassland ecosystem are identified.

A method for quantifying hepatic and intestinal ceramides on mice by UPLC-MS/MS.

BACKGROUND: Ceramide is one type of sphingolipids, is associated with the occurrence of metabolic diseases, including obesity, diabetes, cardiovascular disease, cancer, and nonalcoholic fatty liver disease. Dihydroceramide, the direct precursors of ceramide, which is converted to ceramide with the dihydroceramide desaturase, is recently regarded as involving in various biological processes and metabolic diseases. The liver and gut ceramide levels are interactional in pathophysiological condition, quantifying hepatic and intestinal ceramide levels become indispensable. The aim of this study is to establish a rapid method for the determination of ceramides including dihydroceramides in liver and small intestinal tissues for researching the mechanisms of ceramide related diseases. METHODS: The levels of Cer d18:1/2:0, Cer d18:1/6:0, Cer d18:1/12:0, Cer d18:1/14:0, Cer d18:1/16:0, Cer d18:1/17:0, Cer d18:1/18:0, Cer d18:1/20:0, Cer d18:1/22:0, Cer d18:1/24:1, Cer d18:1/24:0, dHCer d18:0/12:0, dHCer d18:0/14:0, dHCer d18:0/16:0, dHCer d18:0/18:0, dHCer d18:0/24:1 and dHCer d18:0/24:0 in mice liver and small intestine were directly quantified by ultra-high performance liquid chromatography-tandem mass spectrometry after methanol extraction. In detail, liver or small intestine tissues were thoroughly homogenized with methanol. The resultant ceramides were separated on a Waters BEH C18 column using gradient elution within 10 min. Positive electrospray ionization with multiple reaction monitoring was applied to detect. In the end, the levels of ceramides in mice liver and small intestine tissues were quantified by this developed method. RESULTS: The limits of detection and quantification of 11 ceramides and 6 dihydroceramides were 0.01-0.5 ng/mL and 0.02-1 ng/mL, respectively, and all detected ceramides had good linearities (R2 > 0.997). The extraction recoveries of ceramides at three levels were within 82.32%-115.24% in the liver and within 83.21%-118.70% in the small intestine. The relative standard deviations of intra- and inter-day precision were all within 15%. The extracting solutions of the liver and small intestine could be stably stored in the autosampler 24 h at 10 °C, the lyophilized liver and small intestine for ceramides quantification could be stably stored at least 1 week at -80 °C. The ceramides and dihydroceramides in normal mice liver and small intestinal tissues analyzed by the developed method indicated that the detected 9 ceramide and 5 dihydroceramides levels were significantly different, in which Cer d18:1/16:0, Cer d18:1/22:0, Cer d18:1/24:1, Cer d18:1/24:0 and dHCer d18:0/24:1 are the main components in the liver, whereas Cer d18:1/16:0 and dHCer d18:0/16:0 accounts for the majority of proportion in the intestinal tissues. CONCLUSION: A simple and rapid method for the quantification of 11 ceramides and 6 dihydroceramides in the animal tissues was developed and applied. The compositions of ceramides in two tissues suggested that the compositional features should to be considered when exploring the biomarkers or molecular mechanisms.

A Comparative Study on the Mechanism of Delayed-Type Hypersensitivity Mediated by the Recombinant Mycobacterium tuberculosis Fusion Protein ESAT6-CFP10 and Purified Protein Derivative.

While purified protein derivative (PPD) is commonly used as skin diagnostic reagent for tuberculosis (TB) infection, it cannot distinguish effectively Bacillus Calmette-Guérin (BCG) vaccination from Mycobacterium tuberculosis (MTB) complex and nontuberculous mycobacteria infection. The new skin reagent ESAT6-CFP10 (EC) has favorable sensitivity and specificity, which can overcome limitations associated with PPD. At present, EC skin test reactions are mainly characterized by erythema, while PPD mainly causes induration. We conducted a comparative study on the potential differences between EC-induced erythema and PPD-induced induration using a guinea pig model. The size of EC-dependent erythema was similar to that of PPD-induced induration, and an inflammatory response characterized by the infiltration of monocytes, macrophages and lymphocytes, as well as tissue damage, appeared at the injection site. The lymphocytes included CD4+ T and CD8+ T cells, which released IFN-γ as the main cytokine. Both EC erythema and PPD induration could lead to increased levels of acute-phase proteins, and the differential pathways were similar, thus indicating that the main induced immune pathways were similar. The above results indicated that erythema produced by EC could generate the main delayed-type hypersensitivity (DTH) response characteristic of PPD induration, thereby suggesting that erythema might also have a certain diagnostic significance and provide a possible theoretical basis for its use as a diagnostic indicator for detecting MTB infection.

Simultaneous Determination of Pesticide Residues and Mycotoxins in Storage Pu-erh Tea Using Ultra-High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry.

Mycotoxins and pesticides are the most concerning chemical contaminants that can affect the quality of Pu-erh tea during its production and storage. This study presents a method that can simultaneously determine 31 pesticide residues and six mycotoxins in Pu-erh tea within 11 min using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) after QuEChERS extraction. The lower limit of quantification (LOQ) for all analytes ranged between 0.06 and 50 ppb. Recoveries for each pesticide and mycotoxin ranged between 62.0 and 130.3%, with intra- and inter-day precisions lower than 15%. Good linear relationships were obtained, with correlation coefficients of r2 > 0.991 for all analytes. The established method was applied to 31 Pu-erh tea samples, including raw and ripened Pu-erh tea with different storage times. As a result, pesticide residues were not detected in any of the collected samples, and the mycotoxins detected in the samples were well below the official maximum residue limits (MRLs). Notably, the levels of aflatoxin B1 (AFB1), aflatoxin G1 (AFG1) and aflatoxin G2 (AFG2) were lower than 1 ppb in the samples stored for more than 30 years.

Community response of arbuscular mycorrhizal fungi to extreme drought in a cold-temperate grassland.

Climate extremes pose enormous threats to natural ecosystems. Arbuscular mycorrhizal (AM) fungi are key plant symbionts that can affect plant community dynamics and ecosystem stability. However, knowledge about how AM fungal communities respond to climate extremes in natural ecosystems remains elusive. Based on a grassland extreme drought experiment in Inner Mongolia, we investigated the response of AM fungal communities to extreme drought in association with plant communities. The experiment simulated two types of extreme drought (chronic/intense) of once-in-20-year occurrence. AM fungal richness and community composition exhibited high sensitivity to extreme drought and were more sensitive to intense drought than chronic drought. This community sensitivity (i.e. decline in richness and shifts in community composition) of AM fungi can be jointly explained by soil moisture, plant richness, and aboveground productivity. Notably, the robustness of the plant-AM fungal community co-response increased with drought intensity. Our results indicate that AM fungal communities are sensitive to climate extremes, and we propose that the plant community mediates AM fungal community responses. Given the ubiquitous nature of AM associations, their climate sensitivity may have profound consequences on plant communities and ecosystem stability under climate change.

Isolation and Characterization of a Novel Lytic Halotolerant Phage from Yuncheng Saline Lake.

Halophilic phage are a type of virus that exist in salty environments within halophilic archaeal or bacterial hosts. However, relatively few reports on halophilic bacteriophages exist, and our overall understanding of halophilic bacteriophages is quite limited. We used SYBR Green I fluorescent staining to detect the abundance of viruses in Yuncheng Saline Lake, China. Using the double-layer plate method, a lytic phage that could infect halophilic bacterium Salinivibrio sp. YM-43 was isolated and named YXM43. We studied host range, optimal host, morphological characteristics, nucleic acid type, protein composition, and other biological characteristics of the virus. Results reveal a high abundance of this halophilic virus in Yuncheng Saline Lake. The newly isolated bacteriophage YXM43 has a narrow host range, with the most suitable host being Virgibacillus sp. SK39. After purification and enrichment, YXM43 is observed as a spherical particle with a diameter of approximately 30 nm, with no tail. No lipid envelope can be seen in YXM43. The capsid protein of the virus can be separated into seven proteins with molecular weights ranging from 62.0 to 13.0 kDa. YXM43 is a DNA virus with a genome approximately 23 kb. The virus is tolerant of low salinity, and its activity is highest at a temperature of 60 °C and a pH of 10. YXM43 is temperature and pH tolerant, and can adapt to environmental change, even withstanding chloroform treatment. The results indicate that bacteriophage YXM43 is a novel halophilic bacteriophage with broad tolerance to environmental change.

Sex- and Age-Related Metabolic Characteristics of Serum Free Fatty Acids in Healthy Chinese Adults.

Free fatty acids (FFAs), also named nonesterified fatty acids, largely originate from the lipolysis of triacylglycerol stored in adipose tissue. Despite extensive research on sex- and age-dependent effects on lipolysis and lipid mobilization of adipose tissue, the primary differences in the metabolic characteristics of circulating FFAs among normal-weight healthy men and women during aging are still unclear. Here, we measured the concentrations of 45 FFAs in fasting sera of two Chinese community-based studies consisting of 201 metabolically healthy normal-weight adults to ascertain the associations of sex and age with FFA compositions and their upstream and downstream relations. Results showed greater conversions toward n-3 polyunsaturated fatty acids of docosahexaenoic acid and n-6 of docosapentaenoic acid from their precursors in women than in men. Meanwhile, there were significantly positive correlations between the concentrations of a panel of saturated fatty acids with straight chain or branched chain and age in women, whereas no association was found in men. These findings highlight that sex and age should be considered as the potential confounding factors in assessing the risk for metabolic disturbance using FFA biomarkers.

Serum metabolite profiles are associated with the presence of advanced liver fibrosis in Chinese patients with chronic hepatitis B viral infection.

BACKGROUND: Accurate and noninvasive diagnosis and staging of liver fibrosis are essential for effective clinical management of chronic liver disease (CLD). We aimed to identify serum metabolite markers that reliably predict the stage of fibrosis in CLD patients. METHODS: We quantitatively profiled serum metabolites of participants in 2 independent cohorts. Based on the metabolomics data from cohort 1 (504 HBV associated liver fibrosis patients and 502 normal controls, NC), we selected a panel of 4 predictive metabolite markers. Consequently, we constructed 3 machine learning models with the 4 metabolite markers using random forest (RF), to differentiate CLD patients from normal controls (NC), to differentiate cirrhosis patients from fibrosis patients, and to differentiate advanced fibrosis from early fibrosis, respectively. RESULTS: The panel of 4 metabolite markers consisted of taurocholate, tyrosine, valine, and linoelaidic acid. The RF models of the metabolite panel demonstrated the strongest stratification ability in cohort 1 to diagnose CLD patients from NC (area under the receiver operating characteristic curve (AUROC) = 0.997 and the precision-recall curve (AUPR) = 0.994), to differentiate fibrosis from cirrhosis (0.941, 0.870), and to stage liver fibrosis (0.918, 0.892). The diagnostic accuracy of the models was further validated in an independent cohort 2 consisting of 300 CLD patients with chronic HBV infection and 90 NC. The AUCs of the models were consistently higher than APRI, FIB-4, and AST/ALT ratio, with both greater sensitivity and specificity. CONCLUSIONS: Our study showed that this 4-metabolite panel has potential usefulness in clinical assessments of CLD progression in patients with chronic hepatitis B virus infection.

Solid-state fermented Chinese alcoholic beverage (baijiu) and ethanol resulted in distinct metabolic and microbiome responses.

Alcoholic beverages, which are consumed widely in most parts of the world, have long been identified as a major risk factor for all liver diseases, particularly alcoholic liver disease (ALD). Recent compositional analyses suggest that Chinese baijiu (CB), a clear alcoholic liquid distilled from fermented grains, contains large amounts of small molecule bioactive compounds in addition to a significant amount of ethanol (EtOH). Here, in an experimental mouse model, we show that CB caused lower degrees of liver injury than pure EtOH by protecting against the decrease of the relative abundance of Akkermansia and increase of the relative abundance of Prevotella in the gut, thereby preventing the destruction of the intestinal barrier. Furthermore, we demonstrated that EtOH-induced alteration of the gut microbiota profoundly affected the host metabolome. Compared with EtOH feeding, CB feeding resulted in higher concentrations of functional saturated long-chain fatty acids and short-chain fatty acids. The additional mouse models of low dosages of EtOH and of blending baijiu validated that volatile compounds in CB can attenuate EtOH-induced liver damages. Our results provide supporting evidence that ALD was profoundly influenced by host-gut microbiota metabolic interactions and that small molecule organic compounds in CB could attenuate ALD.-Fang, C., Du, H., Zheng, X., Zhao, A., Jia, W., Xu, Y. Solid-state fermented Chinese alcoholic beverage (baijiu) and ethanol resulted in distinct metabolic and microbiome responses.

Tuberculosis vaccine development: from classic to clinical candidates.

Bacillus Calmette-Guérin (BCG) has been in use for nearly 100 years and is the only licensed TB vaccine. While BCG provides protection against disseminated TB in infants, its protection against adult pulmonary tuberculosis (PTB) is variable. To achieve the ambitious goal of eradicating TB worldwide by 2050, there is an urgent need to develop novel TB vaccines. Currently, there are more than a dozen novel TB vaccines including prophylactic and therapeutic at different stages of clinical research. This literature review provides an overview of the clinical status of candidate TB vaccines and discusses the challenges and future development trends of novel TB vaccine research in combination with the efficacy of evaluation of TB vaccines, provides insight for the development of safer and more efficient vaccines, and may inspire new ideas for the prevention of TB.

Template Construction of Porous CoP/COP2 Microflowers Threaded with Carbon Nanotubes toward High-Efficiency Oxygen Evolution and Hydrogen Evolution Electrocatalysts.

Low-cost, high-efficiency, and non-noble metal electrocatalysts are greatly urgent for sustainable energy conversion technologies with CO2-free emission, but these are challenging to construct. Herein, we demonstrate a novel cobaltic-formate frameworks (Co-FFs)-induced strategy to obtain porous flowerlike CoP/CoP2 composite threaded with carbon nanotubes (CoP/CoP2/CNTs). In this approach, a wet chemical precipitation process and then a gas-solid phosphorization method are involved to synthesize the flowerlike Co-FFs/CNTs precursor and the porous CoP/CoP2/CNTs composite, respectively. As bifunctional electrocatalyst, the composite attains a current density of 10 mA cm-2 at a low driving overpotentials of 270 mV for OER and 126 mV for HER in basic and acidic media, respectively. Furthermore, it discloses an exceptional electrocatalytic durability. This excellent electrochemical performance can be attributed to its porous structure and synergistic contribution among different components. The present work provides a facile procedure for fabricating multifunctional materials coated with CNTs.

MOF-Derived Hierarchical CoSe2 with Sheetlike Nanoarchitectures as an Efficient Bifunctional Electrocatalyst.

The exploitation of efficient and stable non-noble-metal bifunctional electrocatalysts is key to the development of hydrogen production technology. Although some progress has been made in the synthesis of transition-metal selenide nanostructures, the preparation of metal-organic framework (MOF)-derived transition-metal selenide electrode materials with more active sites and nanosheet structures remains a significant challenge. Herein, on the basis of the MOFs, the hierarchical CoSe2-160 microcube with sheetlike nanoarchitectures was successfully prepared. In addition, the morphology of cobalt selenides was controlled by adjusting the hydrothermal reaction temperature. Electrochemical experiments show that the CoSe2-160 microcube has a splendid electrocatalytic performance with 10 mA cm-2 at an overpotential of 156 mV and a small Tafel slope of 40 mV dec-1 (in 0.5 M H2SO4) for hydrogen evolution reaction as well as 328 mV and a small Tafel slope of 73 mV dec-1 (in 1 M KOH) for oxygen evolution reaction, respectively. This arises from the nanosheet structures, large surface areas, and abundant active sites. This strategy provides a neoteric synthesis route for the MOF-derived transition-metal selenides with a striking electrocatalytic performance.

Development of Multimarker Diagnostic Models from Metabolomics Analysis for Gestational Diabetes Mellitus (GDM).

Although metabolomics are desirable to understand the pathophysiology of gestational diabetes mellitus (GDM), comprehensive metabolomic studies of GDM are rare. We aimed to offer a holistic view of metabolites alteration in GDM patients and investigate the possible multimarker models for GDM diagnosis. Biochemical parameters and perinatal data of 131 GDM cases and 138 controls were collected. Fasting serum samples at 75 g oral glucose tolerance test were used for metabolites by ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry, ultra performance liquid chromatography-triple triple-quadrupole-mass spectrometry and gas chromatography- time-of- flight mass spectrometry platforms. Significant changes were observed in free fatty acids, bile acids, branched chain amino acids, organic acids, lipids and organooxygen compounds between two groups. In receiver operating characteristic (ROC) analysis, different combinations of candidate biomarkers and metabolites in multimarker models achieved satisfactory discriminative abilities for GDM, with the values of area under the curve (AUC) ranging from 0.721 to 0.751. Model consisting of body mass index (BMI), retinol binding protein 4 (RBP4), n-acetylaspartic acid and C16:1 (cis-7) manifested the best discrimination [AUC 0.751 (95% CI: 0.693-0.809), p < 0.001], followed by model consisting of BMI, Cystatin C, acetylaspartic acid and 6,7-diketoLCA [AUC 0.749 (95% CI: 0.691-0.808), p < 0.001]. Metabolites alteration reflected disorders of glucose metabolism, lipid metabolism, amino acid metabolism, bile acid metabolism as well as intestinal flora metabolism in GDM state. Multivariate models combining clinical markers and metabolites have the potential to differentiate GDM subjects from healthy controls.

Association between serum haptoglobin and carotid arterial functions: usefulness of a targeted metabolomics approach.

BACKGROUND: Serum haptoglobin (Hp) has been closely associated with cardio-cerebrovascular diseases. We investigated a metabolic profile associated with circulating Hp and carotid arterial functions via a targeted metabolomics approach to provide insight into potential mechanisms. METHODS: A total of 240 participants, including 120 patients with type 2 diabetes mellitus (T2DM) and 120 non-diabetes mellitus (non-DM) subjects were recruited in this study. Targeted metabolic profiles of serum metabolites were determined using an AbsoluteIDQ™ p180 Kit (BIOCRATES Life Sciences AG, Innsbruck, Austria). Ultrasound of the bilateral common carotid artery was used to measure intima-media thickness and inter-adventitial diameter. Serum Hp levels were tested by enzyme-linked immunosorbent assay. RESULTS: Serum Hp levels in T2DM patients and non-DM subjects were 103.40 (72.46, 131.99) mg/dL and 100.20 (53.99, 140.66) mg/dL, respectively. Significant differences of 19 metabolites and 17 metabolites were found among serum Hp tertiles in T2DM patients and non-DM subjects, respectively (P < 0.05). Of these, phosphatidylcholine acyl-alkyl C32:2 (PC ae C32:2) was the common metabolite observed in two populations, which was associated with the serum Hp groups and lipid traits (P < 0.05). Furthermore, the metabolite ratios of two acidic amino acids, including aspartate to PC ae C32:2 (Asp/PC ae C32:2) and glutamate to PC ae C32:2 (Glu/PC ae C32:2) were correlated with serum Hp, carotid arterial functions and other biochemical index in both populations significantly (P < 0.05). CONCLUSIONS: Targeted metabolomics analyses might provide a new insight into the potential mechanisms underlying the association between serum Hp and carotid arterial functions.

Reverse-D-4F improves endothelial progenitor cell function and attenuates LPS-induced acute lung injury.

BACKGROUND: Patients with acute lung injury (ALI) have increased levels of pro-inflammatory mediators, which impair endothelial progenitor cell (EPC) function. Increasing the number of EPC and alleviating EPC dysfunction induced by pro-inflammatory mediators play important roles in suppressing ALI development. Because the high density lipoprotein reverse-D-4F (Rev-D4F) improves EPC function, we hypothesized that it might repair lipopolysaccharide (LPS)-induced lung damage by improving EPC numbers and function in an LPS-induced ALI mouse model. METHODS: LPS was used to induce ALI in mice, and then the mice received intraperitoneal injections of Rev-D4F. Immunohistochemical staining, flow cytometry, MTT, transwell, and western blotting were used to assess the effect of Rev-D4F on repairment of lung impairment, and improvement of EPC numbers and function, as well as the signaling pathways involved. RESULTS: Rev-D4F inhibits LPS-induced pulmonary edema and decreases plasma levels of the pro-inflammatory mediators TNF-α and ET-1 in ALI mice. Rev-D4F inhibited infiltration of red and white blood cells into the interstitial space, reduced lung injury-induced inflammation, and restored injured pulmonary capillary endothelial cells. In addition, Rev-D4F increased numbers of circulating EPC, stimulated EPC differentiation, and improved EPC function impaired by LPS. Rev-D4F also acted via a PI3-kinase-dependent mechanism to restore levels of phospho-AKT, eNOS, and phospho-eNOS suppressed by LPS. CONCLUSIONS: These findings indicate that Rev-D4F has an important vasculoprotective role in ALI by improving the EPC numbers and functions, and Rev-D4F reverses LPS-induced EPC dysfuncion partially through PI3K/AKT/eNOS signaling pathway.

Food withdrawal alters the gut microbiota and metabolome in mice.

Food withdrawal as a health-enhancing measure has beneficial effects on aging, disease prevention, and treatment. However, the cellular and molecular mechanisms involving gut microbial changes and metabolic consequences resulting from food withdrawal have yet to be elucidated. In this study, we subjected lean and obese mice to a dietary intervention that consisted of a 4-d complete food withdrawal and an 8-d 50% food withdrawal, and we studied changes in cecal microbiome and host serum metabolome. The abundance of potentially pathogenic Proteobacteria was decreased and Akkermansia muciniphila was elevated by food withdrawal in mice fed a high-fat diet (HFD). Meanwhile, food withdrawal decreased the abundance of metabolites in branched chain amino acid, lipid, and free fatty acid metabolisms in host serum, more so in HFD mice than in normal mice. Microbial predicted function also showed that food withdrawal decreased the abundance of microbes associated with predicted diseases in the HFD group but not in the normal chow group. Correlation between the microbiome data and metabolomics data revealed a strong association between gut microbial and host metabolic changes in response to food withdrawal. In summary, our results showed that food withdrawal was safer and more metabolically beneficial to HFD-induced obese mice than to normal lean mice, and the beneficial effects were primarily derived from the changes in gut microbiota, which were closely associated with the host metabolome.-Zheng, X., Zhou, K., Zhang, Y., Han, X., Zhao, A., Liu, J., Qu, C., Ge, K., Huang, F., Hernandez, B., Yu, H., Panee, J., Chen, T., Jia, W., Jia, W. Food withdrawal alters the gut microbiota and metabolome in mice.

MCEE 2.0: more options and enhanced performance.

A confounding factor is an unstudied factor that affects one or more of the variables that are being studied in an investigation, so the presence of a confounder may lead to inaccurate or biased results. It is well recognized that physiological and environmental factors such as race, diet, age, gender, blood pressure, and diurnal cycle affect mammalian metabolism. To eliminate the noise introduced by confounders into metabolomics studies, a GUI-based method denoted metabolic confounding effect elimination (MCEE) was developed and has since been applied successfully in a wide range of metabolomics studies. To keep up with recent developments in computational metabolomics and a growing number of user requests, an upgraded version of MCEE with more options and enhanced performance was designed and developed. Besides the generalized linear model (GLM) method, a multivariate method for selecting affected metabolites-canonical correlation analysis (CCA)-was introduced, which accounts for complicated correlations and collinearity within the metabolome. Multiple confounders are acceptable and can be identified and processed separately or simultaneously. The effectiveness of this new version of MCEE as well as the pros and cons of the two methodological options were examined using three simulated data sets (a basic model, a model with different sample size ratios, and a sparse model) and two real-world data sets (a human type 2 diabetes mellitus data set and a human arthritis data set). As well as presenting the results of this examination of the new version of MCEE, some instructions on appropriate method selection and parameter setting are provided here. The freely available MATLAB code for MCEE with a GUI has also been updated accordingly at https://github.com/chentianlu/MCEE-2.0 . Graphical abstract.

Post-operative delirium associated with metabolic alterations following hemi-arthroplasty in older patients.

BACKGROUND: post-operative delirium (POD) is a common complication in older patients, though a possible link between metabolic changes and POD development has yet to be investigated. METHODS: older patients with hip fracture who underwent hemi-arthroplasty were recruited, and delirious states were assessed for 3 days after surgery using the confusion assessment method-Chinese revision. Simultaneously, fasting blood samples were collected on the morning of surgery and on the first post-operative day. Ultimately, 244 older patients who met the inclusion and exclusion criteria were assessed. Blood samples from 60 patients with POD and 60 matched controls were analysed using metabolomics platforms. RESULTS: sixty patients (24.6%) developed POD. Principal component analysis scores plot and cross-validated scores plots from orthogonal partial least squares-discriminant analysis were implemented to visualise the differences in metabolites between the two groups before and after surgery (P < 0.05). Our data indicate that levels of ω3 and ω6 fatty acids were lower in the POD group than in the NPOD (non-POD) group both before and after surgery; tricarboxylic cycle intermediate levels were lower in the POD group than in the NPOD group, but glycolysis products were higher in the POD group than in the NPOD group after surgery. Furthermore, the branched-chain amino acid (BCAA)/aromatic amino acid ratio was lower in the POD group than in the NPOD group after surgery. CONCLUSIONS: metabolic abnormalities, including deficiencies in ω3 and ω6 fatty acids, perturbations in tricarboxylic cycle and oxidative stress and metabolic imbalances in BCAA and AAA might contribute to POD development.

Strategy for an Association Study of the Intestinal Microbiome and Brain Metabolome Across the Lifespan of Rats.

There is increased appreciation for the diverse roles of the microbiome-gut-brain axis on mammalian growth and health throughout the lifespan. Numerous studies have demonstrated that the gut microbiome and their metabolites are extensively involved in the communication between brain and gut. Association study of brain metabolome and gut microbiome is an active field offering large amounts of information on the interaction of microbiome, brain and gut but data size and complicated hierarchical relationships were found to be major obstacles to the formation of significant, reproducible conclusions. This study addressed a two-level strategy of brain metabolome and gut microbiome association analysis of male Wistar rats in the process of growth, employing several analytical platforms and various bioinformatics methods. Trajectory analysis showed that the age-related brain metabolome and gut microbiome had similarity in overall alteration patterns. Four high taxonomical level correlated pairs of "metabolite type-bacterial phylum", including "lipids-Spirochaetes", "free fatty acids (FFAs)-Firmicutes", "bile acids (BAs)-Firmicutes", and "Neurotransmitters-Bacteroidetes", were screened out based on unit- and multivariant correlation analysis and function analysis. Four groups of specific "metabolite-bacterium" association pairs from within the above high level key pairs were further identified. The key correlation pairs were validated by an independent animal study. This two-level strategy is effective in identifying principal correlations in big data sets obtained from the systematic multiomics study, furthering our understanding on the lifelong connection between brain and gut.

The ratio of dihomo-γ-linolenic acid to deoxycholic acid species is a potential biomarker for the metabolic abnormalities in obesity.

Bile acid (BA) signaling regulates fatty acid metabolism. BA dysregulation plays an important role in the development of metabolic disease. However, BAs in relation to fatty acids have not been fully investigated in obesity-related metabolic disorders. A targeted metabolomic measurement of serum BA and free fatty acid profiles was applied to sera of 381 individuals in 2 independent studies. The results showed that the ratio of dihomo-γ-linolenic acid (DGLA) to deoxycholic acid (DCA) species (DCAS) was significantly increased in obese individuals with type 2 diabetes (T2DM) from a case-control study and decreased in the remission group of obese subjects with T2DM after metabolic surgery. The changes were closely associated with their metabolic status. These results were consistently confirmed in both serum and liver of mice with diet-induced obesity, implying that such a metabolic alteration in circulation reflects changes occurring in the liver. In vitro studies of human liver L-02 cell lines under BA treatment revealed that DCA and its conjugated form, TDCA, significantly inhibited mRNA expression of fatty acid transport protein 5 in the presence of DGLA, which was involved in hepatocyte DGLA uptake. Thus, the DGLA:DCAS ratio may be a promising biomarker for metabolic abnormalities in obesity.-Lei, S., Huang, F., Zhao, A., Chen, T., Chen, W., Xie, G., Zheng, X., Zhang, Y., Yu, H., Zhang, P., Rajani, C., Bao, Y., Jia, W., Jia, W. The ratio of dihomo-γ-linolenic acid to deoxycholic acid species is a potential biomarker for the metabolic abnormalities in obesity.