GC/MS-Based Analysis of Fatty Acids and Amino Acids in H460 Cells Treated with Short-Chain and Polyunsaturated Fatty Acids: A Highly Sensitive Approach.

The important metabolic characteristics of cancer cells include increased fat production and changes in amino acid metabolism. Based on the category of tumor, tumor cells are capable of synthesizing as much as 95% of saturated and monounsaturated fatty acids through de novo synthesis, even in the presence of sufficient dietary lipid intake. This fat transformation starts early when cell cancerization and further spread along with the tumor cells grow more malignant. In addition, local catabolism of tryptophan, a common feature, can weaken anti-tumor immunity in primary tumor lesions and TDLN. Arginine catabolism is likewise related with the inhibition of anti-tumor immunity. Due to the crucial role of amino acids in tumor growth, increasing tryptophan along with arginine catabolism will promote tumor growth. However, immune cells also require amino acids to expand and distinguish into effector cells that can kill tumor cells. Therefore, it is necessary to have a deeper understanding of the metabolism of amino acids and fatty acids within cells. In this study, we established a method for the simultaneous analysis of 64 metabolites consisting of fatty acids and amino acids, covering biosynthesis of unsaturated fatty acids, aminoacyl-tRNA biosynthesis, and fatty acid biosynthesis using the Agilent GC-MS system. We selected linoleic acid, linolenic acid, sodium acetate, and sodium butyrate to treat H460 cells to validate the current method. The differential metabolites observed in the four fatty acid groups in comparison with the control group indicate the metabolic effects of various fatty acids on H460 cells. These differential metabolites could potentially become biomarkers for the early diagnosis of lung cancer.

Effect of Short-Chain Fatty Acids and Polyunsaturated Fatty Acids on Metabolites in H460 Lung Cancer Cells.

Lung cancer is the most common primary malignant lung tumor. However, the etiology of lung cancer is still unclear. Fatty acids include short-chain fatty acids (SCFAs) and polyunsaturated fatty acids (PUFAs) as essential components of lipids. SCFAs can enter the nucleus of cancer cells, inhibit histone deacetylase activity, and upregulate histone acetylation and crotonylation. Meanwhile, PUFAs can inhibit lung cancer cells. Moreover, they also play an essential role in inhibiting migration and invasion. However, the mechanisms and different effects of SCFAs and PUFAs on lung cancer remain unclear. Sodium acetate, butyrate, linoleic acid, and linolenic acid were selected to treat H460 lung cancer cells. Through untargeted metabonomics, it was observed that the differential metabolites were concentrated in energy metabolites, phospholipids, and bile acids. Then, targeted metabonomics was conducted for these three target types. Three LC-MS/MS methods were established for 71 compounds, including energy metabolites, phospholipids, and bile acids. The subsequent methodology validation results were used to verify the validity of the method. The targeted metabonomics results show that, in H460 lung cancer cells incubated with linolenic acid and linoleic acid, while the content of PCs increased significantly, the content of Lyso PCs decreased significantly. This demonstrates that there are significant changes in LCAT content before and after administration. Through subsequent WB and RT-PCR experiments, the result was verified. We demonstrated a substantial metabolic disparity between the dosing and control groups, further verifying the reliability of the method.

[Impact of provincial infrastructure investment on the vulnerability of social-ecological system in China]. / æˆ‘å›½çœåŸŸåŸºç¡€è®¾æ–½æŠ•å ¥å¯¹ç¤¾ä¼š-生态系统脆弱性的影响.

The impact of infrastructure investment on social-economic system or ecological system has been widely discussed, yet, the overall impact of infrastructure investment on social-ecological system (SES) is still unknown. This study summarized the impact mechanism of infrastructure investment on social ecosystem vulnerability. We first sorted out the impact mechanism of infrastructure investment on SES vulnerability, and then empirically analyzed the effect of provincial infrastructure investment on SES vulnerability by using spatial autocorrelation and spatial econometric models on the basis of accounting provincial per capita infrastructure capital stock and comprehensive evaluation of SES vulnerability. The results showed that the infrastructure capital stock per capita at provincial level increased significantly during 2004-2017, with a spatial pattern that the north was higher than the south and the east/west was higher than the middle in China. The provincial SES vulnerability was improved, with spatial distribution characteristics of gradually getting worse from east to west in China. There was positive spatial correlation between provincial infrastructure investment and SES vulnerability, with aggregation distribution characteristics. There was inverted U-shaped relationship between infrastructure investment and SES vulnerability in China, that was, the appropriate investment of infrastructure at early could decrease SES vulnerability, while over-investment would increase it. Our results revealed the overall impact mechanism and dynamic characteristics of infrastructure investment on SES vulnerability, and could provide theoretical and policy-making support for the coordination of infrastructure construction and SES vulnerability governance at the macro level for China.

Label-free, Water-soluble Fluorescent Peptide Probe for a Sensitive and Selective Determination of Copper Ions.

This study aimed to develop a label-free, sensitive, selective, and environment-friendly fluorescent peptide probe His-His-Trp-His (HHWH) for determining the concentration of copper ion (Cu2+) in aqueous solutions. The results demonstrated that the designed HHWH has a high selectivity and sensitivity for monitoring the concentration of free Cu2+ via quenching of the probe fluorescence upon a binding of Cu2+. The fluorescence intensity of the HHWH had a linear relationship with the concentration of Cu2+ between 10 nM and 10 µM, and the detection limit was 8 nM. Furthermore, HHWH could be regenerated with sulfide ions at least five times. The concentrations of Cu2+ in three different real water samples were detected using this probe, and the results were consistent with the one detected using an atomic absorption spectrometer. Thus, HHWH can be used as an accurate and feasible fluorescent peptide probe for detecting Cu2+ in aqueous solutions.

Mass spectrometric analysis of free fatty acids in infant milk powders by frozen pretreatment coupled with isotope-labeling derivatization.

In combination with frozen pretreatment and carboxyl group derivatization, a novel workflow was developed for the determination of free fatty acids in milk powder. The workflow showed a significantly enhanced performance for comprehensive free fatty acid analysis owing to a highly efficient frozen extraction method. In addition, the advantages of the workflow also involved high sensitivity and great tolerance to a complex matrix. Characteristic fragment ions of derivatization reagents also provide clear evidence for the qualitative analysis of free fatty acids. Fourteen types of free fatty acids in a number of domestic and overseas infant milk powders have been successfully detected. The content of free fatty acids in the different samples was different, which probably indicates the diverse quality of infant milk powder. The workflow is expected to be a pragmatic tool for the analysis of free fatty acids in intricate matrices.