The Black mannentake Amauroderma elmerianum Murr. has been newly found and cultivated in §µ L¹t, ViÖt Nam on mixed substrates, supplemented with inorganic nitrogen (ammonium sulfate), traced with 15N (4% excess). The efficiency of utilization of inorganic N fertilizer is determined about 70%, while organic N derived form various components in substrates (branch and bean powder) is only 7%. The amount of N in inorganic fertilizer added is less than 15% of total N amount in the substrates. The application of N fertilizer in combination with organic components, rich in N in substrates for cultivation of Lingzhi fungi as a material medica with improved quality has been discussed, based on using newly suggested 15N tracer techniques
Inorganic Chemicals ; Nitrogen ; Isotope Labeling

Amine-specific isobaric tagging (iTRAQ) reagents, as a new class of isobaric reagent, were developed in 2004, which, combined with liquid chromatography and tandem mass spectrometry (LC-MS/MS) , have been applied to the identification and quantification of proteins in a wide range of biological samples, including bacteria, yeasts, human tissues, cells, and fluids. As a new method of quantitative proteomics, the technique of iTRAQ allows for the quantitative analysis of four samples simultaneously and displays its advantages of high-flux, food reproducibility, and high sensitivity; it also provides a potential technological platform for studying the mechanisms of the development and progression of prostate cancer.
Humans ; Isotope Labeling ; methods ; Male ; Prostatic Neoplasms ; metabolism ; Proteomics ; methods

Intracellular metabolic fluxes are important to understand metabolic characteristics of cells and to direct metabolic engineering strategies. Because intracellular fluxes cannot be directly assessed, isotope experiments are usually conducted to trace metabolic fluxes. The flux-ratio analysis can reflect high biochemical veracity, be employed to identify the topology of the networks, and offer greatly reduced computational expense for flux determination. In order to apply this metabolic analysis method to better elucidate more cell systems, we discussed in this study the principles, experiments and assays, data interpretation, and other issues that should be considered in flux ratio determination, metabolic flux quantification and its metabolic engineering applications.
Carbon Isotopes ; Cells ; metabolism ; Genetic Engineering ; Humans ; Isotope Labeling ; Metabolic Networks and Pathways ; Metabolism ; Spectrum Analysis

OBJECTIVETo evaluate the iron utilization in children using single stable isotopes tracer.

METHODS57 children aged from 10 to 12 from a primary school of Beijing in 2010 were selected, 30 of them were boys and 27 were girls. All the subjects were given 5 ml artificial enriched ⁵⁷FeSO₄ twice per day within 5 days, and the total amount of ⁵⁷Fe was 30 mg. 5 ml blood were taken at 1 day before and 14 days after test, and all the feces during the test were collected. The samples were detected by AAS and MC-ICP-MS after pre-treatment to determine the content and abundances of iron in samples, then the iron utilization in whole blood were calculated.

RESULTSThe blood volume of male and female subjects 14 days after test were (3.19 ± 0.41) and (3.15 ± 0.29) ml respectively, and there was no significantly difference (t = 1.13, P > 0.05) between them; The amount of ⁵⁷Fe intake by male and female subjects were (27.46 ± 0.25) and (27.29 ± 0.15) mg (t = 1.13, P > 0.05); The amount of ⁵⁷Fe in blood were (5.92 ± 0.71) and (6.30 ± 0.65) mg respectively (t = 2.29, P < 0.05); The iron utilization in whole blood at 14 days of male and female subjects were (20.41 ± 2.03)% and (22.04 ± 0.80)% respectively, male subjects were significantly lower than females (t = 2.51, P < 0.05).

CONCLUSIONSingle stable isotopes tracer can be used in iron utilization evaluation in children, and the iron utilization in whole blood of female children is higher than males.

Biological Availability ; Child ; Female ; Humans ; Iron ; blood ; Isotope Labeling ; methods ; Male

Humans ; Isotope Labeling ; Nuclear Magnetic Resonance, Biomolecular ; Protein Domains ; src-Family Kinases ; chemistry

¹³C metabolic flux analysis (¹³C-MFA) enables the precise quantification of intracellular metabolic reaction rates by analyzing the distribution of mass isotopomers of proteinogenic amino acids or intracellular metabolites through ¹³C labeling experiments. ¹³C-MFA has received much attention as it can help systematically understand cellular metabolic characteristics, guide metabolic engineering design and gain mechanistic insights into pathophysiology. This article reviews the advances of ¹³C-MFA in the past 30 years and discusses its potential and future perspective, with a focus on its application in industrial biotechnology and biomedicine.
Amino Acids ; Carbon Isotopes ; Isotope Labeling ; Metabolic Engineering ; Metabolic Flux Analysis ; Models, Biological

Stable isotope ¹³C labeling is an important tool to analyze cellular metabolic flux. The ¹³C distribution in intracellular metabolites can be detected via mass spectrometry and used as a constraint in intracellular metabolic flux calculations. Then, metabolic flux analysis algorithms can be employed to obtain the flux distribution in the corresponding metabolic reaction network. However, in addition to carbon, other elements such as oxygen in the nature also have natural stable isotopes (e.g., ¹⁷O, ¹⁸O). This makes the isotopic information of elements other than the ¹³C marker interspersed in the isotopic distribution measured by the mass spectrometry, especially that of the molecules containing many other elements, which leads to large errors. Therefore, it is essential to correct the mass spectrometry data before performing metabolic flux calculations. In this paper, we proposed a method for construction of correction matrix based on Python language for correcting the measurement errors due to natural isotope distribution. The method employed a basic power method for constructing the correction matrix with simple structure and easy coding implementation, which can be directly applied to data pre-processing in ¹³C metabolic flux analysis. The correction method was then applied to the intracellular metabolic flux analysis of ¹³C-labeled Aspergillus niger. The results showed that the proposed method was accurate and effective, which can serve as a reliable data correction method for accurate microbial intracellular metabolic flux analysis.
Metabolic Flux Analysis ; Isotope Labeling/methods* ; Carbon Isotopes/metabolism* ; Mass Spectrometry/methods* ; Metabolic Networks and Pathways

AIMTo establish the methods for determining the activity of sphingosine kinase(SPK) and the content of sphingosine 1-phosphate (S1P) in biological samples.

METHODSThe ECV304 cells were transfected with pcDNA3 vector encoding Flag-labeled SPK gene. The expression of SPK was measured by Western blot assay and the activity of SPK was determined by enzymatic reaction, isotope incorporation and thin-layer chromatography methods. The S1P in biological samples was extracted, digested by alkaline phosphatase and then catalyzed by SPK. The S1P contents were determined according to the amounts of products.

RESULTSSPK gene transfection could enhance the expression and activity of SPK in cells markedly, and the cellular S1P was also increased obviously. HGF stimulation could increase the activity of SPK and cellular S1P in ECV304 cells.

CONCLUSIONMethods for determining the activity of SPK and the content of SPK in biological samples were established.

Cell Line ; Cytophotometry ; Humans ; Isotope Labeling ; Lysophospholipids ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; metabolism ; Sphingosine ; analogs & derivatives ; metabolism

The stable isotope labeling by amino acids in culture (SILAC) based quantitative proteomics serves as a gold standard because of the high accuracy and throughput for protein identifications and quantification. In this study, we discussed the application of SILAC technology in mammal model, and developed quantitative internal standard for comparative proteomics of disease model. The C57BL/6J mice fed by special diet containing the 13C6-Lysine and bred F2 generation. We identified and analyzed total proteins of 9 mice tissues of F2 generation, including brain, lung, heart, stomach, intestine, liver, spleen, kidney, and muscle. Quantitative analysis information could evaluate the mice and different tissues' labeling efficiency. Liver was the most efficient, brain the least, and the labeling efficiency were 96.34%±0.90% and 92.62%±1.98% respectively. The average of the labeling efficiency of F2 generation was 95.80%±0.64%, which met the international standard (≥ 95%) for SILAC quantitative proteomics effective study. SILAC technology was successfully extended to mammalian model system, which will provide powerful tools for the mechanism study of the pathophysiology process with mouse model.
Amino Acids ; chemistry ; Animals ; Diet ; veterinary ; Isotope Labeling ; Lysine ; chemistry ; Mice ; Mice, Inbred C57BL ; Proteins ; chemistry ; Proteomics ; methods

OBJECTIVEUsing the stable isotopes as the internal standard of microdialysis technology to establish a new method to study the whole and local brain dynamics of nicotine percutaneous preparations.

METHODUsing th healthy rats as experimental animals, administrating nicotine in abdominal transdermal way, then sample in the blood and brain simultaneously by microdialysis which use deuterium nicotine (DL-nicotine) as internal standard. Detecting the samples by LC-MS/MS method.

RESULTThe configuration process in blood and brain both conforms to 2 compartments model, t1/2 is 29.38 min, t1/2beta is 208.51 min, AUC(0-infinity) is 152 127.10 microg x min x L(-1) in the blood t1/2 is 86.64 min, t1/2beta is 386.00 min, AUC(0-infinity) is 152 820.90 microg x min x L(-1) in the brain.

CONCLUSIONDl-nicotine can be used as internal standard of nicotine to correcte the recovery; Stable isotopes internal standard microdialysis technology can be used for studing the whole and the local pharmacokinetic of nicotine and also provide new ideas and methods to studing the process of new drug delivery system.

Animals ; Brain ; metabolism ; Brain Chemistry ; Deuterium ; chemistry ; Isotope Labeling ; methods ; Male ; Microdialysis ; methods ; Nicotine ; blood ; pharmacokinetics ; Rats ; Rats, Sprague-Dawley