Identification of Active Molecules against Thrombocytopenia through Machine Learning.

Thrombocytopenia, which is associated with thrombopoietin (TPO) deficiency, presents very limited treatment options and can lead to life-threatening complications. Discovering new therapeutic agents against thrombocytopenia has proven to be a challenging task using traditional screening approaches. Fortunately, machine learning (ML) techniques offer a rapid avenue for exploring chemical space, thereby increasing the likelihood of uncovering new drug candidates. In this study, we focused on computational modeling for drug-induced megakaryocyte differentiation and platelet production using ML methods, aiming to gain insights into the structural characteristics of hematopoietic activity. We developed 112 different classifiers by combining eight ML algorithms with 14 molecule features. The top-performing model achieved good results on both 5-fold cross-validation (with an accuracy of 81.6% and MCC value of 0.589) and external validation (with an accuracy of 83.1% and MCC value of 0.642). Additionally, by leveraging the Shapley additive explanations method, the best model provided quantitative assessments of molecular properties and structures that significantly contributed to the predictions. Furthermore, we employed an ensemble strategy to integrate predictions from multiple models and performed in silico predictions for new molecules with potential activity against thrombocytopenia, sourced from traditional Chinese medicine and the Drug Repurposing Hub. The findings of this study could offer valuable insights into the structural characteristics and computational prediction of thrombopoiesis inducers.

Risk screening of mycotoxins and their derivatives in dairy products using a stable isotope dilution assay and LC-MS/MS.

An liquid chromatography-tandem mass spectrometry method coupled with a stable isotope dilution assay was established for the simultaneous detection of 17 mycotoxins and their derivatives (aflatoxins B1 , B2 , G1 , G2 , M1 , and M2 ; fumonisins B1 and B2 ; ochratoxin A; zearalenone; zearalanone; α-zearalanol; α-zearalenol; T-2 toxin; deoxynivalenol; deepoxy-deoxynivalenol; and sterigmatocystin) in milk and dairy products. The mycotoxins were extracted with acidified acetonitrile and the lipids were removed using a Captiva EMR-lipid column. The average recoveries of the target compounds from samples spiked at three different concentrations were 67-102%, and the relative standard deviations of the peak areas were less than 10%. Limits of quantification (S/N = 10) of 0.004-1.25 µg/kg were achieved, which are significantly lower than the maximum levels allowed in various countries and regions for each regulated mycotoxin. Milk and yogurt products from local markets and e-commercial platforms were analyzed using the optimized method. The screening showed that aflatoxin M1 , deoxynivalenol, fumonisins B1 and B2 , and zearalenone could be found in milk and yogurt products, especially those products also containing grains or jujube ingredients, indicating that there is a risk of mycotoxins in dairy products.

Algicidal properties of extracts from Cinnamomum camphora fresh leaves and their main compounds.

Plant allelochemicals are considered as the source of effective, economic and friendly-environmental algaecides. To uncover the anti-algal activities of Cinnamomum camphora fresh leaves and their main algicidal agents, we investigated the inhibitory effects of water and methanol extracts from C. camphora fresh leaves on Microcystis aeruginosa and Chlamydomonas reinhardtii cell growth, analyzed the composition of the water and methanol extracts, and determined the main compounds in extracts on the growth of the two algae and their anti-algal mechanism from photosynthetic abilities. Water and methanol extracts from C. camphora fresh leaves can inhibit M. aeruginosa and C. reinhardtii cell growth, and methanol extracts showed stronger inhibitory effects, due to their more compounds and higher molar concentration. There were 23 compounds in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to the water extracts, 9 new compounds were detected in the methanol extracts, and the molar concentration of total compounds in methanol extracts increased by 1.3 folds. Camphor, α-terpineol and linalool were 3 main compounds in the water and methanol extracts. Their mixture (1: 3: 6) and individual compound showed remarkable inhibition on M. aeruginosa and C. reinhardtii cell growth. The degradation of photosynthetic pigments and the reduction of maximum quantum yield of photosystem II (PSII) photochemistry, coefficient of photochemical quenching as well as apparent electron transport rate in C. reinhardtii cells aggravated gradually with increasing the concentration of the mixture and individual compound, while the non-photochemical dissipation of absorbed light energy increased gradually, which led to the decline of photosynthetic abilities. This indicated that camphor, α-terpineol and linalool were 3 main algicidal agents in C. camphora fresh leaf extracts, and they inhibited algal growth by inducing photosynthetic pigment degradation and declining PSII efficiency. Therefore, C. camphora fresh leaf extracts and their main components have potential utilization values as algaecides.

Inhibitory effects of extracts from Cinnamomum camphora fallen leaves on algae.

Natural allelochemicals are considered as a source of algaecides. To uncover the anti-algal activity of Cinnamomum camphora fallen leaves and promote their usage as algaecides, the composition of their water and methanol extracts was analyzed, and the inhibitory effects of extracts on the growth of Microcystis aeruginosa and Chlamydomonas reinhardtii, and chlorophyll (Chl) content and photosynthetic abilities in C. reinhardtii were investigated. Twenty-five compounds were detected in the water extracts, mainly including terpenoids, esters, alcohols, and ketones. Compared to water extracts, there were more compounds and higher concentration in methanol extracts. Both water and methanol extracts inhibited the growth of the two algae, and 15 mg·ml-1 methanol extracts killed the algal cells after 48 h. The levels of Chl a and Chl b, as well as maximum quantum yield of photosystem II photochemistry (Fv/Fm) in C. reinhardtii cells reduced gradually with increasing the concentration of extracts, while the maximum quantum yield of non-photochemical de-excitation (φDO) increased gradually. At the same concentration, methanol extracts showed stronger inhibitory effects than water extracts, due to their higher number of compounds and higher concentration. Therefore, C. camphora fallen leaves have a potential value as an algaecide.

Effects of phosphorus sources on volatile organic compound emissions from Microcystis flos-aquae and their toxic effects on Chlamydomonas reinhardtii.

There is diverse phosphorus (P) in eutrophicated waters, but it is considered as a crucial nutrient for cyanobacteria growth due to its easy precipitation as insoluble salts. To uncover the effects of complex P nutrients on the emission of volatile organic compounds (VOCs) from cyanobacteria and their toxic effects on other algae, the VOCs from Microcystis flos-aquae supplied with different types and amount of P nutrients were analyzed, and the effects of VOCs and their two main compounds on Chlamydomonas reinhardtii growth were investigated. When M. flos-aquae cells were supplied with K2HPO4, sodium pyrophosphate and sodium hexametaphosphate as the sole P source, 27, 23 and 29 compounds were found, respectively, including furans, sulfocompounds, terpenoids, benzenes, aldehydes, hydrocarbons and esters. With K2HPO4 as the sole P source, the VOC emission increased with reducing P amount, and the maximum emission was found under Non-P condition. In the treatments of M. flos-aquae VOCs under Non-P condition and two main terpenoids (eucalyptol and limonene) in the VOCs, remarkable decreases were found in C. reinhardtii cell growth, photosynthetic pigment content and photosynthetic abilities. Therefore, we deduce that multiple P nutrients in eutrophicated waters induce different VOC emissions from cyanobacteria, and P amount reduction caused by natural precipitation and algal massive growth results in more VOC emissions. These VOCs play toxic roles in cyanobacteria becoming dominant species, and eucalyptol and limonene are two toxic agents.

Enrichment efficiency of lutein in eggs and its function in improving fatty liver hemorrhagic syndrome in aged laying hens.

In this study, we evaluated the enrichment efficiency of lutein in eggs and its function in preventing fatty liver hemorrhagic syndrome (FLHS) in aged laying hens. Five groups of laying hens (65 wk old) were fed basal diets supplemented with 0, 30, 60, 90, or 120 mg/kg of lutein. The supplementation period lasted 12 wk followed by 2 wk of lutein depletion in feed. The results revealed that lutein efficiently enriched the egg yolks and improved their color with a significant increase in relative redness (P < 0.001). Lutein accumulation increased in the egg yolk until day 10, then depletion reached a minimum level after 14 d. Overall, zeaxanthin content in all the groups was similar throughout the experimental period. However, triglycerides and total cholesterol were significantly decreased in the liver (P < 0.05) but not significantly different in the serum (P > 0.05). In the serum, the lipid metabolism enzyme acetyl-CoA synthetase was significantly reduced (P < 0.05), whereas dipeptidyl-peptidase 4 was not significantly different (P > 0.05), and there was no statistical difference of either enzyme in the liver (P > 0.05). Regarding oxidation and inflammation-related indexes, malondialdehyde, tumor necrosis factors alpha, interleukin-6, and interleukin-1 beta were decreased, whereas superoxide dismutase and total antioxidant capacity increased in the liver (P < 0.001). The function of lutein for the same indexes in serum was limited. It was concluded that lutein efficiently enriched the egg yolk of old laying hens to improve their color and reached the highest level on day 10 without being subject to a significant conversion into zeaxanthin. At the same time, lutein prevented liver steatosis in aged laying hens by exerting strong antioxidant and anti-inflammatory functions, but also through the modulation of lipid metabolism, which may contribute to reducing the incidence of FLHS in poultry.

Comprehensive foodomics analysis reveals key lipids affect aroma generation in beef.

Lipids are vital precursors to beef aroma compounds, but the exact lipid molecules influencing aroma generation remain unconfirmed. This study employs gas chromatography-olfactometry-mass spectrometry and absolute quantitative lipidomics to identify beef's aroma and lipid profiles and to examine lipid alterations post-thermal processing. The aim is to understand the role of lipids in aroma generation during beef's raw-to-cooked transition. Eighteen key aroma compounds were identified as significant contributors to the aroma of beef. 265 lipid molecules were quantified accurately, and we found that triglycerides containing C18:1 or C18:2 chains, such as TG(16:0_18:1_18:1), TG(16:0_18:1_18:2), TG(16:0_16:1_18:1), as well as phosphatidylcholine and phosphatidylethanolamine containing PC(16:1e_20:4), PC(16:0e_20:4), PC(18:2e_18:2), and PE(16:1e_20:4), played important roles in the generation of key aroma compounds in beef. C18:1, C18:2, C18:3, and C20:4 were key substrates for the formation of aroma compounds. In addition, lysophosphatidylcholine and lysophosphatidylethanolamine containing unsaturated fatty acid chains may serve as important aroma retainers.

Deposition and bioconversion law of ß-carotene in laying hens after long-term supplementation under adequate vitamin A status in the diet.

ß-Carotene, because it is the precursor of vitamin A and has versatile biological roles, has been applied as a feed additive in the poultry industry for a long time. In this study, we investigated the deposition and bioconversion of ß-carotene in laying hens. A total of 600 Hy-line brown laying hens at 40 wk of age were randomly divided into 5 dietary treatments, each group's dietary supplemental levels of ß-carotene were 0, 15, 30, 60, 120 mg/kg feed, and the vitamin A levels were all 8,000 IU/kg. After 14-wk trial, samples were collected, then carotenoids and different forms of vitamin A were detected using the novel method developed by our laboratory. We found that dietary ß-carotene treatment had no significant effects on laying hens' production performance and egg quality (P > 0.05), except the yolk color. The deposition of ß-carotene in the body gradually increased (P < 0.01) with the supplemental dose, whereas the contents of lutein and zeaxanthin decreased (P < 0.05). When the ß-carotene supplemental level was above 30 mg/kg in the diet, the different forms of vitamin A in in serum, liver, ovary, and yolks were increased compared to the control group (P < 0.05). However, these indicators decreased when the additional dose was 120 mg/kg. Moreover, the mRNA levels of the genes involved in ß-carotene absorption, bioconversion, and negative feedback regulation in duodenal mucosa and liver were upregulated after long-term feeding (P < 0.05). Histological staining of the ovaries indicated that the deposition of ß-carotene led to a lower rate of follicle atresia (P < 0.05), and this positive effects may be related to the antioxidant function of ß-carotene, which caused a reduction of oxidation products in the ovary (P < 0.05). Altogether, ß-carotene could accumulate in laying hens intactly and exert its biological functions in tissue. Meanwhile, a part of ß-carotene could also be converted into vitamin A but this bioconversion has an upper limit and negative feedback regulation.

Comparison of Lipids and Volatile Compounds in Dezhou Donkey Meat with High and Low Intramuscular Fat Content.

The intramuscular fat (IMF) content is considered an important factor for assessing meat quality, and is highly related to meat flavor. However, in donkey meat, the influences of IMF content on lipid and volatile profiles remain unclear. Thus, we conducted lipidomic and volatilomic investigations on high- and low-IMF samples from donkey longissimus dorsi muscle. When the IMF level increased, the monounsaturated fatty acid (especially oleic acid) content significantly increased but the saturated fatty acid content decreased (p < 0.05). Twenty-nine of 876 lipids showed significant differences between the two groups. Volatile profiles from differential IMF content samples were also distinct. Five differential volatile odorants were identified in the two groups: 2-acetyl-2-thiazoline, octanal, 2-pentylfuran, pentanal, and 1-(2-pyridinyl) ethanone. Additionally, strong correlations were found between differential fatty acids and lipids with differential odorants. Thus, the difference in volatile odorants may result from the change in the fatty acid composition and lipid profiles induced by different IMF contents, highlighting the urgent need to increase IMF levels in donkey meat.

Comparative characterization of flavor precursors and volatiles of Taihe black-boned silky fowl and Hy-line Brown yolks using multiomics and GC-O-MS-based volatilomics.

Eggs are nutritious and highly valued by consumers. However, egg flavor varies greatly among different hen breeds. The present study used gas chromatography-olfactometry-mass spectrometry-based volatilomics to identify and compare volatile compounds in Taihe black-boned silky fowl (TS) and Hy-line Brown (HL) egg yolks. In addition, the relationships between the levels of different metabolites and lipids and flavor-associated differences were investigated using multiomics. Twenty-eight odorants in total were identified; among them, the levels of 3-methyl-butanal, 1-octen-3-ol, 2-pentylfuran, and (E, E)-2,4-decadienal differed significantly (P < 0.05) between TS and HL egg yolks. The difference in flavor compounds results in TS egg yolks having a stronger overall odor and flavor and a higher acceptance level than HL egg yolks. Metabolomic analysis revealed that 112 metabolites in the egg yolks were significantly different between the two breeds. Furthermore, these different metabolites in the egg yolks of both breeds were significantly enriched in phenylalanine, tyrosine, and tryptophan biosynthesis pathways and phenylalanine metabolism, alanine, aspartate, and glutamate metabolism pathways (P < 0.05), as identified by both metabolite set enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Lipidomic analysis revealed significant differences in the lipid subclasses, lipid molecules, and fatty acid profiles between the egg yolks from the two breeds. As a result, 48 lipid molecules had variable influence in projection values > 1 based on the partial least squares regression model, which may play a role in the differences in aroma characteristics between the two breeds through oxidative degradation of fatty acids. Our study revealed the metabolite, lipid, and volatility profiles of TS and HL egg yolks and may provide an important basis for improving egg flavor to satisfy various consumer preferences.

Development and application of a SFC-DAD-MS/MS method to determine carotenoids and vitamin A in egg yolks from laying hens supplemented with ß-carotene.

ß-Carotene, a provitamin A carotenoid, can be converted into vitamin A in animals' bodies, and can also be accumulated intactly in many animal products. In this study, supercritical fluid chromatography-tandem mass spectrometry was utilized to determine ß-carotene and different forms of vitamin A in eggs simultaneously. According to the results, ß-carotene contained in yolk reached a plateau after about 2 weeks of supplementation. With an increase in dietary supplement level, the amount of ß-carotene gradually increased, as well as slightly changing the yolk color. Moreover, the contents of retinoids including retinol, retinyl propionate, retinyl palmitate and retinyl stearate were also elevated in yolks with the ß-carotene additive levels; meanwhile, the lutein and zeaxanthin decreased. On the whole, ß-carotene in the diet of laying hens could be partially deposited in egg yolk, and the contents of vitamin A in yolk could be increased due to ß-carotene bioconversion.

Characterization of meat quality traits, fatty acids and volatile compounds in Hu and Tan sheep.

Sheep breed has a major influence on characteristics of meat quality and intramuscular fat (IMF), however, studies into the relationship between sheep breed and meat quality traits rarely consider the large variation in IMF within breed. In this study, groups of 176 Hu and 76 Tan male sheep were established, weaned at 56 days old, with similar weights, and representative samples were selected based on the distribution of IMF in each population, to investigate variations in meat quality, IMF and volatile compound profiles between breeds. Significant differences were observed in drip loss, shear force, cooking loss, and color coordinates between Hu and Tan sheep (p < 0.01). The IMF content and the predominate unsaturated fatty acids, oleic and cis, cis-linoleic acids, were similar. Eighteen out of 53 volatile compounds were identified as important odor contributors. Of these 18 odor-active volatile compounds, no significant concentration differences were detected between breeds. In another 35 volatile compounds, γ-nonalactone was lower in Tan sheep relative to Hu sheep (p < 0.05). In summary, Tan sheep exhibited lower drip loss, higher shear force values, and redder color, had less saturated fatty acids, and contained less γ-nonalactone against Hu sheep. These findings improve understanding of aroma differences between Hu and Tan sheep meat. Graphical Abstract.

Metabolome-Based Genome-Wide Association Study of Duck Meat Leads to Novel Genetic and Biochemical Insights.

Meat is among the most consumed foods worldwide and has a unique flavor and high nutrient density in the human diet. However, the genetic and biochemical bases of meat nutrition and flavor are poorly understood. Here, 3431 metabolites and 702 volatiles in 423 skeletal muscle samples are profiled from a gradient consanguinity segregating population generated by Pekin duck × Liancheng duck crosses using metabolomic approaches. The authors identified 2862 metabolome-based genome-wide association studies (mGWAS) signals and 48 candidate genes potentially modulating metabolite and volatile levels, 79.2% of which are regulated by cis-regulatory elements. The level of plasmalogen is significantly associated with TMEM189 encoding plasmanylethanolamine desaturase 1. The levels of 2-pyrrolidone and glycerophospholipids are regulated by the gene expression of AOX1 and ACBD5, which further affects the levels of volatiles, 2-pyrrolidone and decanal, respectively. Genetic variations in GADL1 and CARNMT2 determine the levels of 49 metabolites including L-carnosine and anserine. This study provides novel insights into the genetic and biochemical basis of skeletal muscle metabolism and constitutes a valuable resource for the precise improvement of meat nutrition and flavor.

Normal phase LC coupled with direct analysis in real time MS for the chiral analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and jasmonic acid.

Normal phase chiral LC (NPLC) has been proved to be powerful and efficient for chiral separation. However, the combination of NPLC with ESI or atmospheric pressure chemical ionization MS is restricted by the poor ionization efficiency and thermal fragmentations of analytes to some extent. Direct analysis in real time MS (DART-MS) is an ambient ionization technique that shows high ionization efficiency of the analytes in the normal phase mobile phase. In this work, we coupled chiral NPLC to DART-MS for the chiral qualitative and quantitative analysis of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and jasmonic acid enantiomers. Satisfactory results for the enantiomers of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol operating in the positive mode were obtained in terms of linearity (2.5-250 µg/mL, R(2) , 0.999-1.000) and repeatability (25 µg/mL, RSDs, 4.7-5.6%). Moreover, chiral NPLC-DART-MS resulted in the simultaneous chiral separation and detection of jasmonic acid enantiomers, which are very difficult to be analyzed by NPLC-ESI-MS and NPLC-APCI-MS. Compared with the coupled techniques of NPLC-ESI-MS and NPLC-APCI-MS, NPLC-DART-MS showed advantages in increasing the ionization efficiency and reducing the in-source thermal fragmentation of analytes.

Ion-exchange-membrane-based enzyme micro-reactor coupled online with liquid chromatography-mass spectrometry for protein analysis.

In this article, we developed a membrane-based enzyme micro-reactor by directly using commercial polystyrene-divinylbenzene cation-exchange membrane as the support for trypsin immobilization via electrostatic and hydrophobic interactions and successfully applied it for protein digestion. The construction of the reactor can be simply achieved by continuously pumping trypsin solution through the reactor for only 2 min, which was much faster than the other enzyme immobilization methods. In addition, the membrane reactor could be rapidly regenerated within 35 min, resulting in a "new" reactor for the digestion of every protein sample, completely eliminating the cross-interference of different protein samples. The amount and the activity of immobilized trypsin were measured, and the repeatability of the reactor was tested, with an RSD of 3.2% for the sequence coverage of cytochrome c in ten digestion replicates. An integrated platform for protein analysis, including online protein digestion and peptide separation and detection, was established by coupling the membrane enzyme reactor with liquid chromatography-quadrupole time-of-flight mass spectrometry. The performance of the platform was evaluated using cytochrome c, myoglobin, and bovine serum albumin, showing that even in the short digestion time of several seconds the obtained sequence coverages was comparable to or higher than that with in-solution digestion. The system was also successfully used for the analysis of proteins from yeast cell lysate.

Isotope-Coded Chemical Derivatization Method for Highly Accurately and Sensitively Quantifying Short-Chain Fatty Acids.

Short-chain fatty acids (SCFAs) are major gut microbiota-derived metabolites, which can reshape the intestine and regulate gut immunity. The application of conventional GC methods has been hampered for quantifying low-concentrated SCFAs, such as in serum, saliva, and digesta of germ-free animals. Herein, we established a LC-MS method to quantify SCFAs after 5-(dimethylamino)-1-carbohydrazide-isoquinoline (DMAQ) derivatization. The DMAQ derivatization significantly enhanced the detection sensitivity and improved separation of SCFAs. 2-methylbutyric acid and 3-methylbutyric acid were separately quantitated. Moreover, the matrix effect was diminished using DMAQ-13C/15N-tagged SCFAs as internal standards. The established quantitation method was successfully applied in the analysis of plasma and cecum digesta collected from neonatal piglets, revealing that significant increases in biological SCFA contents in cecum digesta were closely related to the variation of gut microbial diversity. The established quantitation method is capable of sensitively and comprehensively quantifying SCFAs that may provide insights into underlying gut-microbiota functions.

Changes in lipids and aroma compounds in intramuscular fat from Hu sheep.

Intramuscular fat (IMF) content is associated with lamb flavor and largely varies between individuals of the same breed. However, studies investigating the effects of IMF variations on lipid profiles and aroma compounds are limited. Here, we performed lipidomic and volatilomic profiling of high-IMF and low-IMF Hu lambs. Triglycerides and diglycerides in the high-IMF group were significantly higher than those in the low-IMF group (p < 0.05). Seventy-nine of 842 lipids identified were significantly different between the groups under positive and negative ion modes (variable importance in projection > 1, p < 0.05). Volatilomic analyses revealed that the aroma profiles also differed between the groups. Fifteen aroma compounds, mainly originating from lipid oxidation, could be responsible for this difference. Thus, our findings provide a comprehensive understanding of the increases in IMF content that drive consumers' satisfaction and also provide a basis for underpinning breeding value for IMF.

Untargeted Profiling and Differentiation of Volatiles in Varieties of Meat Using GC Orbitrap MS.

Volatile compounds play vital roles in food sensory attributes and food quality. An analysis of volatile compounds could illustrate the sensory attributes at the microscale level. Here, untargeted profiling approaches for volatiles in five most-consumed meat species were established using headspace SPME-GC/high resolution Orbitrap MS. An extended high-resolution database of meat volatile compounds was established to enhance the qualification accuracy. Using sulfur-containing compounds, aldehydes, and ketones as the research model, the parameters including fiber coating types, extraction temperature, extraction time, and desorbing time were optimized. Principle component analysis, volcano analysis and partial least squares discriminant analysis were applied to run the classification and the selection of discriminant markers between meat varieties, respectively. Different varieties could be largely distinguished according to the volatiles' profiles. 1-Octen-3-ol, 1-octen-3-one, 2-pentyl furan and some other furans degraded from n-6 fatty acids would contribute to distinguishing duck meat from other categories, while methyl esters mainly from oleic acid as well as dimethyl sulfoxide and carbon disulfide possibly produced from the sulfur-containing amino acids contributed to the discrimination of beef. Therefore, volatiles' profiling not only could interpret the aroma style in meat but also could be another promising method for meat differentiation and authentication.

In-capillary non-covalent labeling and determination of tomato systemin with quantum dots in capillary electrophoresis with laser-induced fluorescence detection.

Quantum dots (QDs), with their superior size-dependent fluorescence properties, have been employed as non-covalent fluorescent labels for the determination of tomato systemin (TomSys) by capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection. The optimum conditions of in-capillary labeling and CE separation were investigated in detail, and complete separation of QDs-labeled TomSys from free QDs labels was achieved. Satisfactory results were obtained in terms of linearity (R(2)=0.998), sensitivity (limit of detection, 66 fmol) and repeatability (run-to-run RSDs of migration time and peak area, 0.9 and 4.6%, respectively; day-to-day RSDs of migration time and peak area, 3.1 and 11.9%, respectively). The established CE-LIF method was later applied in the detection of TomSys spiked in the sample of tomato leaves, which showed the applicability of the proposed method in the analysis of the target plant peptide hormone in the complex matrix.

Optimization of the nitrogen and oxygen element distribution in microalgae by ammonia torrefaction pretreatment and subsequent fast pyrolysis process for the production of N-containing chemicals.

In this work, ammonia (NH3) torrefaction pretreatment (ATP) was developed to optimize the nitrogen and oxygen element distribution of microalgae via the N-doping and oxygen removal reaction, which could obviously improve the potential use of microalgae as a feedstock for the production of N-heterocyclic chemicals through fast pyrolysis technology. The nitrogen content increased from 8.3% of raw microalgae to 11.51% at 300 °C of ATP, while the oxygen content decreased from 35.96% to 21.61%, because of the Maillard reactions. In addition, the nitrogen-doping ratio and oxygen removal ratio of ATP was much higher than the conventional nitrogen torrefaction pretreatment (NTP). With the increase of ATP torrefaction temperature or the pyrolysis temperature, the relative content of the N-containing compounds increased, while the O-containing compounds decreased. For the N-heterocyclic chemicals, higher pyrolysis temperature favored the formation of pyrroles, while inhibited the formation of pyridines and indoles.