A novel bioprospecting strategy via 13C-based high-throughput probing of active methylotrophs inhabiting oil reservoir surface soil.

Methane-oxidizing bacteria (MOB) have long been considered as a microbial indicator for oil and gas prospecting. However, due to the phylogenetically narrow breath of ecophysiologically distinct MOB, classic culture-dependent approaches could not discriminate MOB population at fine resolution, and accurately reflect the abundance of active MOB in the soil above oil and gas reservoirs. Here, we presented a novel microbial anomaly detection (MAD) strategy to quantitatively identify specific indicator methylotrophs in the surface soils for bioprospecting oil and gas reservoirs by using a combination of 13C-DNA stable isotope probing (SIP), high-throughput sequencing (HTS), quantitative PCR (qPCR) and geostatistical analysis. The Chunguang oilfield of the Junggar Basin was selected as a model system in western China, and type I methanotrophic Methylobacter was most active in the topsoil above the productive oil wells, while type II methanotrophic Methylosinus predominated in the dry well soils, exhibiting clear differences between non- and oil reservoir soils. Similar results were observed by quantification of Methylobacter pmoA genes as a specific bioindicator for the prediction of unknown reservoirs by grid sampling. A microbial anomaly distribution map based on geostatistical analysis further showed that the anomalous zones were highly consistent with petroleum, geological and seismic data, and validated by subsequent drilling. Over seven years, a total of 24 wells have been designed and drilled into the targeted anomaly, and the success rate via the MAD prospecting strategy was 83 %. Our results suggested that molecular techniques are powerful tools for oil and gas prospecting. This study indicates that the exploration efficiency could be significantly improved by integrating multi-disciplinary information in geophysics and geomicrobiology while reducing the drilling risk to a greater extent.

A green-footprint approach for parallel multiclass analysis of contaminants in roasted coffee via LC-HRMS.

The development and validation of a simple, comprehensive, and environment-friendly procedure to determine pesticide residues, naturally occurring and processing contaminants in roasted coffee is presented. A solid-liquid extraction of pesticides and mycotoxins with ethyl acetate and the concurrent partition of acrylamide to an aqueous phase follows a parallel analytical strategy that requires a single analytical portion to determine contaminants that are typically analyzed by dedicated single residue methods. The partition rules the lipids out of the aqueous extract before an "in-tube" dispersive solid phase microextraction (dSPME) for acrylamide retention. This is followed by the elution with buffer prior to injection. This extract is independently introduced into the system front end followed by the injection of the compounds from the organic phase, yet all spotted in the same run. A novel liquid chromatography high-resolution mass spectrometry (LC-HRMS) method setup enables the quantification of 186 compounds at 10 µg/kg, 226 at 5 µg/kg, and the acrylamide at 200 µg/kg for a total of 414 molecules, with acceptable recoveries (70-120%) and precision (RSD < 20%) making this strategy significantly faster and cost-effective than the dedicated single residue methods. Even though the presence of chlorpyrifos, acrylamide, and ochratoxin A was confirmed on samples of different origins, the findings were below the limit of quantification. During the storage of raw coffee, no proof of masking of OTA was found; however, condensation with glucose was evidenced during thermal processing experiments with sucrose by using stable isotope labeling (SIL). No detected conjugates were found in roasted nor in commercial sugar-added torrefacto samples, an industrial processing usually carried out above the decomposition temperature of the disaccharide.

Anaerobic dihydrogen consumption of nutrient-limited aquifer sediment microbial communities examined by stable isotope analysis.

The biogeochemical consequences of dihydrogen (H2) underground storage in porous aquifers are poorly understood. Here, the effects of nutrient limitations on anaerobic H2 oxidation of an aquifer microbial community in sediment microcosms were determined in order to evaluate possible responses to high H2 partial pressures. Hydrogen isotope analyses of H2 yielded isotope depletion in all biotic setups indicating microbial H2 consumption. Carbon isotope analyses of carbon dioxide (CO2) showed isotope enrichment in all H2-supplemented biotic setups indicating H2-dependent consumption of CO2 by methanogens or homoacetogens. Homoacetogenesis was indicated by the detection of acetate and formate. Consumption of CO2 and H2 varied along the differently nutrient-amended setups, as did the onset of methane production. Plotting carbon against hydrogen isotope signatures of CH4 indicated that CH4 was produced hydrogenotrophically and fermentatively. The putative hydrogenotrophic Methanobacterium sp. was the dominant methanogen. Most abundant phylotypes belonged to typical ferric iron reducers, indicating that besides CO2, Fe(III) was an important electron acceptor. In summary, our study provides evidence for the adaptability of subsurface microbial communities under different nutrient-deficient conditions to elevated H2 partial pressures.

Traceability and authentication in agri-food production: A multivariate approach to the characterization ofthe Italian food excellence elephant garlic (Allium ampeloprasum L.), a vasoactive nutraceutical.

A research platform for food authentication was set up by combining stable isotope ratio analysis, metabolomics by gas and liquid mass-spectrometry and NMR investigations, chemometric analyses for food excellences. This multi-analytical approach was tested on samples of elephant garlic (Allium ampeloprasum L.), a species belonging to the same genus of common garlic (Allium ampeloprasum L.), mainly produced in southern Tuscany-(Allium ampeloprasum). The isotopic composition allowed the product to be geographically characterized. Flavonoids, like (+)-catechin, cinnamic acids, quercetin glycosides were identified. The samples showed also a significant amount of dipeptides, sulphur-containing metabolites and glutathione, the latter of which could be considered a molecular marker of the analyzed elephant garlic. For nutraceutical profiling to reach quality labels, extracts were investigated in specific biological assays, displaying interesting vasorelaxant properties in rat aorta by mediating nitric oxide release from the endothelium and exhibited positive inotropic and negative chronotropic effects in rat perfused heart.

Hepatic ChREBP orchestrates intrahepatic carbohydrate metabolism to limit hepatic glucose 6-phosphate and glycogen accumulation in a mouse model for acute Glycogen Storage Disease type Ib.

OBJECTIVE: Carbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation. METHODS: The current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo. RESULTS: ShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown. CONCLUSIONS: Our data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions.

Unveiling the nitrogen and phosphorus removal potential: Comparative analysis of three coastal wetland plant species in lab-scale constructed wetlands.

It is well accepted that tidal wetland vegetation performs a significant amount of water filtration for wetlands. However, there is currently little information on how various wetland plants remove nitrogen (N) and phosphorus (P) and how they differ in their denitrification processes. This study compared and investigated the denitrification and phosphorus removal effects of three typical wetland plants in the Yangtze River estuary wetland (Phragmites australis, Spartina alterniflora, and Scirpus mariqueter), as well as their relevant mechanisms, using an experimental laboratory-scale horizontal subsurface flow constructed wetland (CW). The results showed that all treatment groups with plants significantly reduced N pollutants as compared to the control group without plants. In comparison to S. mariqueter (77.2-83.2%), S. alterniflora and P. australis had a similar total nitrogen (TN)removal effectiveness of nearly 95%. With a removal effectiveness of over 99% for ammonium nitrogen (NH4+-N), P. australis outperformed S. alterniflora (95.6-96.8%) and S. mariqueter (94.6-96.5%). The removal of nitrite nitrogen (NO2--N)and nitrate nitrogen (NO3--N)from wastewater was significantly enhanced by S. alterniflora compared to the other treatment groups. Across all treatment groups, the removal rate of PO43--P was greater than 95%. P. australis and S. alterniflora considerably enriched more 15N than S. mariqueter, according to the results of the 15N isotope labeling experiment. While the rhizosphere and bulk sediments of S. alterniflora were enriched with more simultaneous desulfurization-denitrification bacterial genera (such as Paracoccus, Sulfurovum, and Sulfurimonas), which have denitrification functions, the rhizosphere and bulk sediments of P. australis were enriched with more ammonia-oxidizing archaea and ammonia-oxidizing bacteria. As a result, compared to the other plants, P. australis and S. alterniflora demonstrate substantially more significant ability to remove NH4+-N and NO2--N/NO3--N from simulated domestic wastewater.

Development and Validation of a Stable Isotope Dilution Headspace-SPME-GC/MS Method for the Determination of Vanillin in Fragrant Vegetable Oils.

It has been reported that vanillin has been intentionally added to enhance the taste and flavor of low-quality vegetable oils. Therefore, it is crucial to investigate the accurate concentrations of vanillin in three types of fragrant vegetable oils commonly consumed in China. In this study, a method has been developed for the quantification of vanillin in commercial fragrant vegetable oils using the stable isotope dilution assay (SIDA) and headspace-solid-phase microextraction (HS-SPME) coupled with gas chromatography/mass spectrometry (GC/MS). The limit of detection (LOD) and limit of quantification (LOQ) of the analyte were determined to be 20 µg kg-1 and 50 µg kg-1, respectively. The validation study demonstrated that the recoveries ranged from 89% to 101%, with intra-day and inter-day precision being less than 7.46%. A survey of 80 commercially available fragrant vegetable oils was performed using the present method. Vanillin was found to be widely present in fragrant vegetable oils, with sesame oils showing the highest average content (842.6 µg kg-1), followed by rapeseed oils (262.1 µg kg-1) and peanut oils (115.0 µg kg-1). The results indicate that the proposed method is a simple, accurate, and eco-friendly approach for determining the presences of vanillin in fragrant vegetable oils.

In Situ Discrimination and Cultivation of Active Degraders in Soils by Genome-Directed Cultivation Assisted by SIP-Raman-Activated Cell Sorting.

The identification and in situ cultivation of functional yet uncultivable microorganisms are important to confirm inferences regarding their ecological functions. Here, we developed a new method that couples Raman-activated cell sorting (RACS), stable-isotope probing (SIP), and genome-directed cultivation (GDC)─namely, RACS-SIP-GDC─to identify, sort, and cultivate the active toluene degraders from a complex microbial community in petroleum-contaminated soil. Using SIP, we successfully identified the active toluene degrader Pigmentiphaga, the single cells of which were subsequently sorted and isolated by RACS. We further successfully assembled the genome of Pigmentiphaga based on the metagenomic sequencing of 13C-DNA and genomic sequencing of sorted cells, which was confirmed by gyrB gene comparison and average nucleotide identity determination. Additionally, the genotypes and phenotypes of this degrader were directly linked at the single-cell level, and its complete toluene metabolic pathways in petroleum-contaminated soil were reconstructed. Based on its unique metabolic properties uncovered by genome sequencing, we modified the traditional cultivation medium with antibiotics, amino acids, carbon sources, and growth factors (e.g., vitamins and metals), achieving the successful cultivation of RACS-sorted active degrader Pigmentiphaga sp. Our results implied that RACS-SIP-GDC is a state-of-the-art approach for the precise identification, targeted isolation, and cultivation of functional microbes from complex communities in natural habitats. RACS-SIP-GDC can be used to explore specific and targeted organic-pollution-degrading microorganisms at the single-cell level and provide new insights into their biodegradation mechanisms.

Quality control of Ganoderma lucidum by using C, H, O, and N stable isotopes and C and N contents for geographical traceability.

Rationale: Ganoderma lucidum (G. lucidum) is a popular medicinal fungus that has been used in traditional medicine for decades, with its provenance influencing its medicinal and commercial worth. The amount of active ingredients and the price of G. lucidum from different origins vary significantly; hence, fraudulent labeling is common. Reliable techniques for G. lucidum geographic verification are urgently required to safeguard the interests of consumers, producers, and honest dealers. A stable isotope is widely acknowledged as a useful traceability technique and could be developed to confirm the geographical origin of G. lucidum. Methods: G. lucidum samples from various sources and in varying stages were identified by using δ 13C, δD, δ 18O, δ 15N, C, and N contents combined with chemometric tools. Chemometric approaches, including PCA, OPLS-DA, PLS, and FLDA models, were applied to the obtained data. The established models were used to trace the origin of G. lucidum from various sources or track various stages of G. lucidum. Results: In the stage model, the δ 13C, δD, δ 18O, δ 15N, C, and N contents were considered meaningful variables to identify various stages of G. lucidum (bud development, growth, and maturing) using PCA and OPLS-DA and the findings were validated by the PLS model rather than by only four variables (δ 13C, δD, δ 18O, and δ 15N). In the origin model, only four variables, namely δ 13C, δD, δ 18O, and δ 15N, were used. PCA divided G. lucidum samples into four clusters: A (Zhejiang), B (Anhui), C (Jilin), and D (Fujian). The OPLS-DA model could be used to classify the origin of G. lucidum. The model was validated by other test samples (Pseudostellaria heterophylla), and the external test (G. lucidum) by PLS and FLDA models demonstrated external verification accuracy of up to 100%. Conclusion: C, H, O, and N stable isotopes and C and N contents combined with chemometric techniques demonstrated considerable potential in the geographic authentication of G. lucidum, providing a promising method to identify stages of G. lucidum.

[Responses of tree growth and intrinsic water-use efficiency of Robinia pseudoacacia to climate factors]. / åˆºæ§ç”Ÿé•¿å’Œå† åœ¨æ°´åˆ†åˆ©ç”¨æ•ˆçŽ‡å¯¹æ°”å€™å› å­çš„å“åº”.

We investigated tree growth in Robinia pseudoacacia plantations at Ansai in Shaanxi Province and at Ji-xian in Shanxi Province by comparing the tree-ring width, basal area increase (BAI), δ13C value, intrinsic water-use efficiency (iWUE), and stomatal regulation. We quantified the responses of tree growth and iWUE to climatic factors at each site. The tree-ring width at Ansai and Jixian decreased with stand age, whereas the BAI at Ansai increased, and that at Jixian decreased after the BAI peaked. The δ13C value and iWUE of trees at Jixian were higher than those at Ansai. The iWUE of trees at both sites was similar to the constant intercellular CO2 concentration/atmospheric CO2 concentration (Ci/Ca) scenario, indicating that the Ci of trees was elevated with increasing Ca, while the stomata remained open. The BAI at Ansai was significantly positively correlated with highest temperature in May, relative humidity in June, precipitation in August, relative humidity in September, and standardized precipitation evapotranspiration index (SPEI) in September and October of current year, but negatively correlated with temperature in June. The BAI at Jixian was significantly positively correlated with SPEI in June and July, and lowest temperature in October of current year. The iWUE of trees at Ansai was significantly positively correlated with relative humidity and precipitation in June of the current year, but negatively correlated with minimum temperature in May, relative humidity in June, and temperature and maximum temperature in July of current year. A significant positive correlation between iWUE of trees at Jixian and lowest temperature in June of current year was detected. At the annual scale, the BAI of trees at Ansai was positively correlated with precipitation and SPEI, but no significant relationship was observed for trees at Jixian. However, the iWUE of trees at both sites was significantly affected by precipitation. Path analysis showed that SPEI and minimum temperature had a direct effect on BAI and iWUE of trees at Ansai, whereas precipitation and average temperature indirectly affected BAI and iWUE through SPEI. The highest temperature had a direct effect on tree growth at Jixian, whereas precipitation, minimum temperature, and average temperature had direct effects on iWUE. These results suggested that SPEI was the main climatic factor that affected the growth of R. pseudoacacia, while Ci was an important physiological factor. Our results could provide reference for the protection and management of R. pseudoacacia plantations under climate change.

Geographical origin traceability of mulberry leaves using stable hydrogen, oxygen, and carbon isotope ratios.

Geographical discrimination of mulberry leaves is very important for their efficacy and quality as a traditional Chinese medicine. Stable hydrogen, oxygen, and carbon isotope ratios were measured in 292 mulberry leaves collected at 2 growth stages in 2 seasons from 8 regions of China. A stepwise linear discriminant analysis (LDA) approach were proposed to combine with stable isotope technology to tracing the origin of mulberry leaves. The results showed that leaves sampled in autumn were extremely depleted in 2H and 18O and slightly enriched in 13C compared with leaves sampled in summer, correlated with the effect of season, transpiration and photorespiration on stable isotopes. δ2H and δ18O of the leaves were enriched during the growth process. The overall discrimination accuracy of the autumn tender model was 81%, demonstrating that analysis of δ2H, δ18O, and δ13C is a promising technique for tracing the geographical origin of mulberry leaves, although season, growth stage and number of samples affect the accuracy of discrimination.

Effects of soil organic carbon metabolism on electro-bioremediation of petroleum-contaminated soil.

Soil organic carbon (SOC) potentially interacts with microbial metabolism and may affect the degradation of petroleum-derived carbon (PDC) in the electro-bioremediation of petroleum-contaminated soil. This study evaluated the interactions among organic carbon, soil properties, and microbial communities to explore the role of SOC during the electro-bioremediation process. The results showed that petroleum degradation exerted superposition and synergistic electrokinetic and bioremediation effects, as exemplified by the EB and EB-PR tests, owing to the maintenance and enhancement of SOC utilization (P/S value), respectively. The highest P/S value (2.0-2.4) was found in the electrochemical oxidation zone due to low SOC consumption. In the biological oxidation zones, electric stimulation enhanced the degradation of PDC and SOC, with higher average P/S values than those of the Bio test. Soil pH, Eh, inorganic ions, and bioavailable petroleum fractions were the main factors reshaping the microbial communities. SOC metabolism effectively buffered the stress of environmental factors and pollutants while maintaining functional bacterial abundance, microbial alpha diversity, and community similarity, thus saving the weakened PDC biodegradation efficiency in the EB and EB-PR tests. The study of the effect of SOC metabolism on petroleum biodegradation contributes to the development of sustainable low-carbon electro-bioremediation technology.

Differential Inhibition of Anaplerotic Pyruvate Carboxylation and Glutaminolysis-Fueled Anabolism Underlies Distinct Toxicity of Selenium Agents in Human Lung Cancer.

Past chemopreventive human trials on dietary selenium supplements produced controversial outcomes. They largely employed selenomethionine (SeM)-based diets. SeM was less toxic than selenite or methylseleninic acid (MSeA) to lung cancer cells. We thus investigated the toxic action of these Se agents in two non-small cell lung cancer (NSCLC) cell lines and ex vivo organotypic cultures (OTC) of NSCLC patient lung tissues. Stable isotope-resolved metabolomics (SIRM) using 13C6-glucose and 13C5,15N2-glutamine tracers with gene knockdowns were employed to examine metabolic dysregulations associated with cell type- and treatment-dependent phenotypic changes. Inhibition of key anaplerotic processes, pyruvate carboxylation (PyC) and glutaminolysis were elicited by exposure to MSeA and selenite but not by SeM. They were accompanied by distinct anabolic dysregulation and reflected cell type-dependent changes in proliferation/death/cell cycle arrest. NSCLC OTC showed similar responses of PyC and/or glutaminolysis to the three agents, which correlated with tissue damages. Altogether, we found differential perturbations in anaplerosis-fueled anabolic pathways to underlie the distinct anti-cancer actions of the three Se agents, which could also explain the failure of SeM-based chemoprevention trials.

Anaerobic selenite-reducing bacteria and their metabolic potentials in Se-rich sediment revealed by the combination of DNA-stable isotope probing, metagenomic binning, and metatranscriptomics.

Microorganisms play a critical role in the biogeochemical cycling of selenium (Se) in aquatic environments, particularly in reducing the toxicity and bioavailability of selenite (Se(IV)). This study aimed to identify putative Se(IV)-reducing bacteria (SeIVRB) and investigate the genetic mechanisms underlying Se(IV) reduction in anoxic Se-rich sediment. Initial microcosm incubation confirmed that Se(IV) reduction was driven by heterotrophic microorganisms. DNA stable-isotope probing (DNA-SIP) analysis identified Pseudomonas, Geobacter, Comamonas, and Anaeromyxobacter as putative SeIVRB. High-quality metagenome-assembled genomes (MAGs) affiliated with these four putative SeIVRB were retrieved. Annotation of functional gene indicated that these MAGs contained putative Se(IV)-reducing genes such as DMSO reductase family, fumarate and sulfite reductases. Metatranscriptomic analysis of active Se(IV)-reducing cultures revealed significantly higher transcriptional levels of genes associated with DMSO reductase (serA/PHGDH), fumarate reductase (sdhCD/frdCD), and sulfite reductase (cysDIH) compared to those in cultures not amended with Se(IV), suggesting that these genes played important roles in Se(IV) reduction. The current study expands our knowledge of the genetic mechanisms involved in less-understood anaerobic Se(IV) bio-reduction. Additinally, the complementary abilities of DNA-SIP, metagenomics, and metatranscriptomics analyses are demonstrated in elucidating the microbial mechanisms of biogeochemical processes in anoxic sediment.

The mitochondrial Ca2+ channel MCU is critical for tumor growth by supporting cell cycle progression and proliferation.

Introduction: The mitochondrial uniporter (MCU) Ca2+ ion channel represents the primary means for Ca2+ uptake by mitochondria. Mitochondrial matrix Ca2+ plays critical roles in mitochondrial bioenergetics by impinging upon respiration, energy production and flux of biochemical intermediates through the TCA cycle. Inhibition of MCU in oncogenic cell lines results in an energetic crisis and reduced cell proliferation unless media is supplemented with nucleosides, pyruvate or α-KG. Nevertheless, the roles of MCU-mediated Ca2+ influx in cancer cells remain unclear, in part because of a lack of genetic models. Methods: MCU was genetically deleted in transformed murine fibroblasts for study in vitro and in vivo. Tumor formation and growth were studied in murine xenograft models. Proliferation, cell invasion, spheroid formation and cell cycle progression were measured in vitro. The effects of MCU deletion on survival and cell-death were determined by probing for live/death markers. Mitochondrial bioenergetics were studied by measuring mitochondrial matrix Ca2+ concentration, membrane potential, global dehydrogenase activity, respiration, ROS production and inactivating-phosphorylation of pyruvate dehydrogenase. The effects of MCU rescue on metabolism were examined by tracing of glucose and glutamine utilization for fueling of mitochondrial respiration. Results: Transformation of primary fibroblasts in vitro was associated with increased MCU expression, enhanced MCU-mediated Ca2+ uptake, altered mitochondrial matrix Ca2+ concentration responses to agonist stimulation, suppression of inactivating-phosphorylation of pyruvate dehydrogenase and a modest increase of mitochondrial respiration. Genetic MCU deletion inhibited growth of HEK293T cells and transformed fibroblasts in mouse xenograft models, associated with reduced proliferation and delayed cell-cycle progression. MCU deletion inhibited cancer stem cell-like spheroid formation and cell invasion in vitro, both predictors of metastatic potential. Surprisingly, mitochondrial matrix [Ca2+], membrane potential, global dehydrogenase activity, respiration and ROS production were unaffected. In contrast, MCU deletion elevated glycolysis and glutaminolysis, strongly sensitized cell proliferation to glucose and glutamine limitation, and altered agonist-induced cytoplasmic Ca2+ signals. Conclusion: Our results reveal a dependence of tumorigenesis on MCU, mediated by a reliance on MCU for cell metabolism and Ca2+ dynamics necessary for cell-cycle progression and cell proliferation.

Use of Theoretical Subjects to Develop a Method for Assessing Equivalence of Dietary Vitamin A in a Mixed Diet.

BACKGROUND: Although the vitamin A (VA) equivalency of provitamin A carotenoids from single foods or capsules has been studied using several approaches, there is currently no reliable method to determine VA equivalency for mixed diets. OBJECTIVES: To reach the objective of identifying a method to determine the VA equivalency of provitamin A carotenoids in mixed diets, we tested a new approach using preformed VA as proxy for provitamin A. METHODS: We studied 6 theoretical subjects who were assigned physiologically plausible values for dietary VA intake, retinol kinetic parameters, plasma retinol pool size, and VA total body stores. Using features in the Simulation, Analysis and Modeling software, we specified that subjects ingested a tracer dose of stable isotope-labeled VA on day 0 followed by 0-µg supplemental VA or 200, 400, 800, 1200, 1600, and 2000 µg VA daily from day 14 to day 28; we assigned VA absorption to be 75%. For each supplement level, we simulated plasma retinol specific activity (SAp) over time and calculated the mean decrease in SAp relative to 0 µg. Group mean data were fitted to a regression equation to calculate predicted VA equivalency at each supplement level on day 28. RESULTS: For each subject, higher VA supplement loads resulted in lower SAp, with the magnitude of the decrease differing among subjects. The mean predicted amount of absorbed VA was within 25% of individual subjects' assigned amount for 4 of the 6 subjects, and the mean ratio of predicted to assigned amount of absorbed VA over all supplement loads ranged from 0.60 to 1.50, with an overall mean ratio of 1.0. CONCLUSIONS: Results for preformed VA suggest that this protocol may be useful for determining VA equivalency of provitamin A carotenoids in free-living subjects if mixed diets with known provitamin A content were substituted for the VA supplements.

Petrogenesis of extra-large flake graphite at the Bissett Creek deposit, Canada.

The petrogenesis of extra-large flake graphite is enigmatic. The Bissett Creek graphite deposit, consisting of flake graphite hosted in upper-amphibolite facies quartzofeldspathic gneisses and rare aluminous gneisses, provides an analogue for graphite exploration. In the Bissett Creek gneisses, graphite is homogeneously distributed and composes 2-10 vol. % of the rocks. Disseminated graphite flakes (~ 1 to 6 mm in size) are interleaved with biotite and are petrologically associated with upper-amphibolite facies metamorphic mineral assemblages. Thermobarometry and phase equilibrium modeling yield peak temperatures of > 760 °C at 0.5-0.9 GPa. Whole-rock samples with abundant graphite yield δ13CVPDB from - 28 to - 14‰. δ34SVCDT values of sulfide-bearing samples vary from 10 to 15‰. Sulfur and carbon isotope values are compatible with a biogenic origin, flake graphite probably formed from metamorphism of in situ organic material. However, the variability of δ13C values from the deposit along with graphite microstructures suggest that carbon-bearing metamorphic fluid (or melt) generated during metamorphism may have remobilized carbon resulting in anomalously large to extra-large flake sizes. This may be a common mechanism globally to explain large graphite flake sizes where graphite formed through in situ metamorphism of organic matter is coarsened due to remobilization of CO2-rich fluids (or melt) during high-temperature metamorphism. Supplementary Information: The online version contains supplementary material available at 10.1007/s00126-022-01145-9.

[Discrimination of cultivation modes of Dendrobium nobile based on content of mineral elements and ratios of nitrogen stable isotopes].

This study explored the feasibility of mineral element content and ratios of nitrogen isotopes to discriminate the cultivation mode of Dendrobium nobile in order to provide theoretical support for the discrimination of the cultivation mode of D. nobile. The content of 11 mineral elements(N, K, Ca, P, Mg, Na, Fe, Cu, Zn, Mn, and B) and nitrogen isotope ratios in D. nobile and its substrate samples in three cultivation methods(greenhouse cultivation, tree-attached cultivation, and stone-attached cultivation) were determined. According to the analysis of variance, principal component analysis, and stepwise discriminant analysis, the samples of different cultivation types were classified. The results showed that the nitrogen isotope ratios and the content of elements except for Zn were significantly different among different cultivation types of D. nobile(P<0.05). The results of correlation analysis showed that the nitrogen isotope ratios, mineral element content, and effective component content in D. nobile were correlated with the nitrogen isotope ratio and mineral element content in the corresponding substrate samples to varying degrees. Principal component analysis can preliminarily classify the samples of D. nobile, but some samples overlapped. Through stepwise discriminant analysis, six indicators, including δ~(15)N, K, Cu, P, Na, and Ca, were screened out, which could be used to establish the discriminant model of D. nobile cultivation methods, and the overall correct discrimination rates after back-substitution test, cross-check, and external validation were all 100%. Therefore, nitrogen isotope ratios and mineral element fingerprints combined with multivariate statistical analysis could effectively discriminate the cultivation types of D. nobile. The results of this study provide a new method for the identification of the cultivation type and production area of D. nobile and an experimental basis for the quality evaluation and quality control of D. nobile.

Comparison of Total Body Vitamin A Stores Using Individual versus Population 13C-Natural Abundance of Serum Retinol in Preschool Children and Women Residing in 6 Diverse African Countries.

BACKGROUND: Stable isotope techniques using 13C to assess vitamin A (VA) dietary sources, absorption, and total body VA stores (TBSs) require determination of baseline 13C abundance. 13C-natural abundance is approximately 1.1% total carbon, but varies with foods consumed, supplements taken, and food fortification with synthetic retinyl palmitate. OBJECTIVES: We determined 13C variation from purified serum retinol and the resulting impact on TBSs using pooled data from preschool children in Burkina Faso, Cameroon, Ethiopia, South Africa, Tanzania, and Zambia and Zambian women. METHODS: Seven studies included children (n = 639; 56 ± 25 mo; 48% female) and one in women (n = 138; 29 ± 8.5 y). Serum retinol 13C-natural abundance was determined using GC-C-IRMS. TBSs were available in 7 studies that employed retinol isotope dilution (RID). Serum CRP and α1-acid-glycoprotein (AGP) were available from 6 studies in children. Multivariate mixed models assessed the impact of covariates on retinol 13C. Spearman correlations and Bland-Altman analysis compared serum and milk retinol 13C and evaluated the impact of using study- or global-retinol 13C estimates on calculated TBSs. RESULTS: 13C-natural abundance (%, median [Q1, Q3]) differed among countries (low: Zambia, 1.0744 [1.0736, 1.0753]; high: South Africa, 1.0773 [1.0769, 1.0779]) and was associated with TBSs, CRP, and AGP in children and with TBSs in women. 13C-enrichment from serum and milk retinol were correlated (r = 0.52; P = 0.0001). RID in children and women using study and global estimates had low mean bias (range, -3.7% to 2.2%), but larger 95% limits of agreement (range, -23% to 37%). CONCLUSIONS: 13C-natural abundance is different among human cohorts in Africa. Collecting this information in subgroups is recommended for surveys using RID. When TBSs are needed on individuals in clinical applications, baseline 13C measures are important and should be measured in all enrolled subjects.

Selenium and toxic metals in human hair of the Dashan Region, China: Concentrations, sources, and antagonism effect.

The Dashan Region was a Se-rich region of China. In this study, 131 residents' human hair samples were collected. The concentrations of Se and toxic metals were analyzed, and the health risk was estimated using the concentration data. Cd and As concentrations were significantly higher than in East China. Se and most toxic metal concentrations increased with age (except for the aged people). Furthermore, gender and smoking habits might have a significant impact on toxic metals and Se levels. Multivariable statistics analysis revealed that Se and toxic metals primarily originate in the environment and are then transferred to the human body via the food chain. Dietary habits had an effect on the Se and As concentrations in hair, according to the results of stable isotope analysis. To assess detoxification ability, the Se/ toxic metal molar ratio was used as an indicator. The results demonstrated that the antagonistic effect of Se and Cd, As, Cr, and Hg (molar ratio > 1) could effectively protect residents in the study area from Cd and As pollution in daily life.