[Mechanism of liver injury induced by alcohol extract of salt-processed Psoraleae Fructus based on chemical modification of protein].

Salt-processed Psoraleae Fructus is a commonly used tonic in clinical practice. However, its usage is restricted due to the inherent toxicity. The covalent modification of proteins by reactive metabolites(RMs) plays a role in the hepatotoxicity of salt-processed Psoraleae Fructus. This study delves into the protein covalent modification by RMs generated from psoralen/isopsoralen, the primary toxic components of salt-processed Psoraleae Fructus, by liquid chromatography-mass spectrometry(LC-MS), aiming to elucidate the mechanism underlying the hepatic injury induced by salt-processed Psoraleae Fructus. Biochemical methods were utilized to measure the levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), catalase(CAT), malondialdehyde(MDA), superoxide dismutase(SOD), reduced glutathione(GSH), and glutathione S-transferase(GST) in mice. The pathological changes in the liver were observed by hematoxylin-eosin(HE) staining. Subsequently, ultra performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry(UPLC-Q-TOF-MS) was employed to identify the primary toxic components of psoralen/isopsoralen and the RMs in salt-processed Psoraleae Fructus. Covalent bonding adducts of the toxic components/RMs with GSH and free amino acids were identified to investigate the effects of the toxic components on modification sites and patterns of amino acids. The modifications of RMs were incorporated into the variable modifications of Proteome Discoverer, and the target proteins of psoralen/isopsoralen were detected by liquid chromatography-quadrupole exactive-mass spectrometry. Lastly, Label-free quantitative proteomics was adopted to screen differential proteins, which were further subjected to KEGG and GO enrichment analyses and confirmed by qPCR. The results indicated that compared with the control group, salt-processed Psoraleae Fructus significantly elevated the ALT, AST, and MDA levels and lowered the SOD, CAT, GSH, and GST levels in a dose-dependent manner, while causing obvious vacuolization and inflammatory cell infiltration in mouse hepatocytes. Furthermore, the livers of mice in the salt-processed Psoraleae Fructus group showed the presence of five RMs of psoralen/isopsoralen, two adducts with GSH, and one adduct with cysteine. In addition, 10 proteins modified by the RMs of psoralen/isopsoralen were identified. A total of 133 differential proteins were detected in the livers of mice in the salt-processed Psoraleae Fructus group, including 92 with up-regulated expression and 41 with down-regulated expression. These differential proteins mainly involved ribosomes, rRNAs, and glutathione, affecting the proteasome pathway. The qPCR results were consistent with the differential proteins. These findings suggest that the RMs of psoralen/isopsoralen can covalently bind to GSH and modify cysteine and lysine residues of liver proteins. This covalent modification of proteins by harmful substances can potentially result in liver damage. Therefore, it can be inferred that the oxidative stress damage induced by salt-processed Psoraleae Fructus may be associated with the abnormality of proteasome and its complex, biosynthesis of ribosomes and their nucleoprotein complex, rRNA binding, and glutathione binding.

[MODIS-driven estimation of regional evapotranspiration in Karst area of Southwest China based on the Penman-Monteith-Leuning algorithm.] / 基于Penman-Monteith-Leuning遥感模型的西南喀斯特区域蒸散发估算.

Karst area in southwestern China is characterized with complex topography, low soil water capacity, and fragile ecosystem. Accurate estimation of regional evapotranspiration is essential for ecological restoration and water resources management in southwestern China. Based on observed evapotranspiration and meteorological data, this study aimed to estimate spatial upscale evapotranspiration using the MOD15A2 LAI and Penman-Monteith-Leuning (PML) model, within which the stomatal conductance and soil wetness index were optimized by the least-square method. The results showed that the modeled ET well fitted with the observations, with the determination coefficient, Nash efficiency coefficient and RMSE being 0.85, 0.75 and 1.56 mm·d-1, respectively. The ET exhibited clear seasonality and reached to its maximum in summer, coinciding with vegetation phenology. The annual ET ranged from 534 to 1035 mm·a-1, with strong spatial heterogeneity which highly related to the precipitation. Evapotranspiration may be affected by precipitation as well as land use types.

Profiling of polyunsaturated fatty acids in human serum using off-line and on-line solid phase extraction-nano-liquid chromatography-quadrupole-time-of-flight mass spectrometry.

Polyunsaturated fatty acids (PUFAs) play a pivotal role in the biological effects, and are the potential biomarkers for some diseases. However, the structural diversity and similarity, the low concentration, and the interference of high abundant endogenous components challenge the PUFAs profiling. Herein, a novel analytical approach, off-line and on-line solid phase extraction-nano-liquid chromatography-quadrupole-time-of-flight mass spectrometry (off-line and on-line SPE-nano-LC-Q-TOF-MS), was established to monitor the PUFAs. The combination of off-line and on-line SPE removed most of impurities, and the recoveries ranged from 80.1% to 93.0% and the matrix effects were from 85.1% to 92.8%. Using this method, 51 PUFAs could be separated well and quantified with the limits of quantification between 0.006 and 2.2 pg. Finally, this developed method was applied successfully to simultaneously qualify and quantify the potential biomarkers in the allergic patients. 21 PUFAs including LTB4, 5S-, 11S-, 15S-HETE and 15S-HEPE showed significant differences. Our study indicated that the established method has the potential to sensitively and accurately determine the PUFAs in biological samples.

[Effects of irrigation amount and frequency on soil water distribution and water use efficiency in a cotton field under mulched drip irrigation].

A 2-year (2009 and 2010) field experiment was carried out to investigate the effects of irrigation amount (300, 375, and 450 mm) and irrigation frequency (once every 3-, 7-, and 10 days) on the soil water distribution and cotton water use efficiency (WUE) under mulched drip irrigation in North Xinjiang. When the irrigation amount was 375 mm, irrigation once every 3 days induced a higher water content in surface soil (0-20 cm) in the whole growth season of cotton but made the deeper (below 40 cm) soil not moistened enough. Irrigation once every 10 days benefited the irrigation water penetrated downward or sideways and made the deeper soil have a higher water content; however, this drip irrigation did not replenish water in time, and made the surface soil water content lower. Overall, drip irrigation once every 7 days benefited the uniform distribution of irrigation water in soil profile. Under the same irrigation frequencies, the larger the irrigation amount, the higher the soil water content. The cotton water consumption in all treatments had the similar pattern, i. e., lower at seedling stage (averagely < 1.7 mm x d(-1)), increased gradually since squaring stage and reached the maximum at full bloom stage (about 8.7 mm x d(-1)), and decreased at onen-boll staue (about 1.0 mm x d(-1). Under the natural condition, the total cotton water consumption had close correlation with irrigation amount but poor correlation with irrigation frequency, and the cotton WUE decreased significantly with increasing irrigation amount. When the irrigation amount was 300 mm, the WUE was higher but the yield production decreased markedly, whereas excessive irrigation (450 mm) had no significant yield-increasing effect but wasted water. It was suggested that irrigation with an amount of 375 mm and a frequency of once every 7- or 10 days could be an appropriate drip irrigation mode for the local cotton field under natural condition.