(+)-Borneol Protects Dopaminergic Neuronal Loss in Methyl-4-phenyl-1,2,3,6-tetrahydropyridine-Induced Parkinson's Disease Mice: A Study of Dopamine Level using In Vivo Brain Microdialysis.

Considerable research efforts have been directed toward the symptom relief of Parkinson's disease (PD) by attenuating dopamine (DA) depletion. One common feature of these existing therapies is their unavailability of preventing the neurodegenerative process of dopaminergic neurons. (+)-Borneol, a natural highly lipid-soluble bicyclic monoterpene, has been reported to regulate the levels of monoamine neurotransmitters in the central nervous system and exhibit neuroprotective effects. However, the effect of (+)-borneol on the dopaminergic neuronal loss of methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice is not defined. Herein, we first report that 30 mg/kg (+)-borneol significantly attenuated the motor deficits of PD mice, which benefits from markedly increasing the level of DA and decreasing the metabolic rate of DA in the striatum of conscious and freely moving mouse detected by ultraperformance liquid chromatography tandem mass spectrometry online combined with in vivo brain microdialysis sampling. It is worth noting that the enhanced level of DA by (+)-borneol was enabled by the reduction in loss of tyrosine hydroxylase-immunoreactive dopaminergic neurons in the substantia nigra and striatum and promotion of reserpine- or nomifensine-induced DA release in PD mice. Interestingly, (+)-borneol evidently inhibited the decreased expression levels of DA transporter (DAT) and vesicular monoamine transporter 2 (VMAT2) on the MPTP mouse model of PD. Moreover, (+)-borneol suppressed the neuroinflammation by inhibiting the production of IL-1ß, IL-6, and TNF-α and attenuated oxidative stress by decreasing the level of MDA and increasing the activities of SOD and GSH-px in PD mice. These findings demonstrate that (+)-borneol protects DA neurons by inhibiting neuroinflammation and oxidative stress. Further research work for the neuroprotection mechanism of (+)-borneol will focus on reactive oxygen species-mediated apoptosis. Therefore, (+)-borneol is a potential therapeutic candidate for retarding the neurodegenerative process of PD.

Inoculation of Yarrowia lipolytica promotes the growth of lactic acid bacteria, Debaryomyces udenii and the formation of ethyl esters in sour meat.

Yarrowia lipolytica N12 and A13 with high lipase activity obtained by mutagenesis were inoculated into sour meat, and their effects on physicochemical properties, microbial community succession, free amino acids, and volatile compounds of sour meat were investigated. Inoculation fermentation increased the contents of free amino acids observably, rapidly reduced pH, promoted the accumulation of total acids, decreased 2-thiobarbituric acid reactive substances (TBARS) values. In addition, the addition of Y. lipolytica might contribute to the growth of lactic acid bacteria, Candida spp., and Debaryomyces udenii, which play an important role in production of volatile compounds. It was shown that inoculation promoted the production of esters, aldehydes, and alcohols, especially ethyl esters, giving sour meat a better meat flavor. Besides, it was found that Y. lipolytica A13 had better fermenting property. Sample of A13 group had higher contents of ethyl esters, free amino acids and dominant microorganisms. The results may help to provide new strains for sour meat fermentation.

Genome-Wide Identification and Expression Profiling Analysis of SWEET Family Genes Involved in Fruit Development in Plum (Prunus salicina Lindl).

SWEETs (sugars will eventually be exported transporters) play a vital role in longer-distance sugar transportation, and thus control carbon flow and energy metabolism in plants. SWEET genes have been identified in various plant species, but their functions in fruit development remain uncharacterized. Here, we isolated 15 putative PsSWEETs from the Prunus salicina genome. For further analysis, comprehensive bioinformatics methods were applied to determine the gene structure, chromosome distribution, phylogeny, cis-acting regulatory elements, and expression profiles of PsSWEETs. qRT-PCR analysis suggested that these SWEETs might have diverse functions in the development of plum fruit. The relative expression levels of PsSWEET1 and PsSWEET9 were obviously higher in ripened fruit than the ones in other developmental stages, suggesting their possible roles in the transport and accumulation of sugars in plum fruit. Positive correlations were found between the expression level of PsSWEET3/10/13 and the content of sucrose, and the expression level of PsSWEET2 and the content of fructose, respectively, during the development of 'Furongli' fruit, suggesting their possible roles in the accumulation of sucrose and fructose. The current study investigated the initial genomic characterization and expression patterns of the SWEET gene family in plum, which could provide a foundation for the further understanding of the functional analysis of the SWEET gene family.

The genome of low-chill Chinese plum "Sanyueli" (Prunus salicina Lindl.) provides insights into the regulation of the chilling requirement of flower buds.

Chinese plum (Prunus salicina Lindl.) is a stone fruit that belongs to the Prunus genus and plays an important role in the global production of plum. In this study, we report the genome sequence of the Chinese plum "Sanyueli", which is known to have a low-chill requirement for flower bud break. The assembled genome size was 282.38 Mb, with a contig N50 of 1.37 Mb. Over 99% of the assembly was anchored to eight pseudochromosomes, with a scaffold N50 of 34.46 Mb. A total of 29,708 protein-coding genes were predicted from the genome and 46.85% (132.32 Mb) of the genome was annotated as repetitive sequence. Bud dormancy is influenced by chilling requirement in plum and partly controlled by DORMANCY ASSOCIATED MADS-box (DAM) genes. Six tandemly arrayed PsDAM genes were identified in the assembled genome. Sequence analysis of PsDAM6 in "Sanyueli" revealed the presence of large insertions in the intron and exon regions. Transcriptome analysis indicated that the expression of PsDAM6 in the dormant flower buds of "Sanyueli" was significantly lower than that in the dormant flower buds of the high chill requiring "Furongli" plum. In addition, PsDAM6 expression was repressed by chilling treatment. The genome sequence of "Sanyueli" plum provides a valuable resource for elucidating the molecular mechanisms responsible for the regulation of chilling requirements, and it is also useful for the identification of the genes involved in the control of other important agronomic traits and molecular breeding in plum.

Lipase Addition Promoted the Growth of Proteus and the Formation of Volatile Compounds in Suanzhayu, a Traditional Fermented Fish Product.

This work investigated the effect of lipase addition on a Chinese traditional fermented fish product, Suanzhayu. The accumulation of lactic acid and the decrease of pH during the fermentation were mainly caused by the metabolism of Lactobacillus. The addition of lipase had little effect on pH and the bacterial community structure but promoted the growth of Proteus. The addition of lipase promotes the formation of volatile compounds, especially aldehydes and esters. The formation of volatile compounds is mainly divided into three stages, and lipase had accelerated the fermentation process. Lactobacillus, Enterococcus and Proteus played an important role not only in inhibition of the growth of Escherichia-Shigella, but also in the formation of flavor. This study provides a rapid fermentation method for the Suanzhayu process.

Activation of PsMYB10.2 Transcription Causes Anthocyanin Accumulation in Flesh of the Red-Fleshed Mutant of 'Sanyueli' (Prunus salicina Lindl.).

Plum is one of the most important stone fruits in the world and anthocyanin-rich plums are increasingly popular due to their health-promoting potential. In this study, we investigated the mechanisms of anthocyanin accumulation in the flesh of the red-fleshed mutant of the yellow-fleshed plum 'Sanyueli'. RNA-Seq and qRT-PCR showed that anthocyanin biosynthetic genes and the transcription factor PsMYB10.2 were upregulated in the flesh of the mutant. Functional testing in tobacco leaves indicated that PsMYB10.2 was an anthocyanin pathway activator and can activate the promoter of the anthocyanin biosynthetic genes PsUFGT and PsGST. The role of PsMYB10.2 in anthocyanin accumulation in the flesh of plum was further confirmed by virus-induced gene silencing. These results provide information for further elucidating the underlying mechanisms of anthocyanin accumulation in the flesh of plum and for the breeding of new red-fleshed plum cultivars.

Effects of flavourzyme addition on physicochemical properties, volatile compound components and microbial community succession of Suanzhayu.

Flavourzyme is known to promote protein decomposition, resulting in more peptides and amino acids which can improve the quality of fermented foods. In this study, the effects of flavourzyme addition on the fermentation of Suanzhayu fish were investigated. The results showed that the addition of 50 U/g flavourzyme reduced the water activity (aw) of products and promoted the release of trichloroacetic acid (TCA)-soluble peptides and free amino acids (FAAs). Thus, the stability of the product was improved and its nutritional value was increased. In addition, with the addition of flavourzyme, Lactobacillus and Saccharomyces more quickly became the dominant genera in the fermentation. Furthermore, the formation of alcohols, aldehydes, and esters was promoted in flavourzyme addition group. Redundant analysis (RDA) indicated that Lactobacillus and Lactococcus play important roles in the formation of flavors, especially for the characteristic flavors of Suanzhayu. Flavourzyme addition may be a novel method to greatly improve the properties of Suanzhayu and shorten the fermentation time.

Illumina® Sequencing Reveals Candidate Genes of Carotenoid Metabolism in Three Pummelo Cultivars (Citrus Maxima) with Different Pulp Color.

Pummelo (Citrus maxima) is one of important fruit trees, which belongs to Citrus species. The fruits of different pummelo cultivars have different colors and differ in the contents of carotenoid. Our results clearly showed that 'Huangjinmiyou' (HJMY) has the highest content of ß-carotene, followed by 'Hongroumiyou' (HRMY) and 'Guanximiyou' (GXMY). Lycopene is dominantly accumulated in HRMY. However, the molecular mechanism underlying the carotenoid accumulation in pummelo flesh is not fully understood. In this study, we used the RNA-Seq technique to investigate the candidate genes of carotenoid metabolism in the flesh of pummelo cv. GXMY and its mutants HRMY and HJMY in three development periods of fruit. After data assembly and bioinformatic analysis, a total of 357 genes involved in biosynthesis of secondary metabolites were isolated, of which 12 differentially expressed genes (DEGs) are involved in carotenoid biosynthesis. Among these 12 DEGs, phytoene synthase (PSY2), lycopene ß-cyclase (LYCB2), lycopene Ɛ-cyclase (LYCE), carotenoid cleavage dioxygenases (CCD4), 9-cis-epoxycarotenoid dioxygenase (NCED2), aldehyde oxidase 3 (AAO3), and ABA 8'-hydroxylases (CYP707A1) are the most distinct DEGs in three pummelo cultivars. The co-expression analysis revealed that the expression patterns of several transcription factors such as bHLH, MYB, ERF, NAC and WRKY are highly correlated with DEGs, which are involved in carotenoid biosynthesis. In addition, the expression patterns of 22 DEGs were validated by real-time quantitative PCR (RT-qPCR) and the results are highly concordant with the RNA-Seq results. Our results provide a global vision of transcriptomic profile among three pummelo cultivars with different pulp colors. These results would be beneficial to further study the molecular mechanism of carotenoid accumulation in pummelo flesh and help the breeding of citrus with high carotenoid content.

Changes in secondary metabolites, organic acids and soluble sugars during the development of plum fruit cv. 'Furongli' (Prunus salicina Lindl).

BACKGROUND: Organic acids, sugars and pigments are key components that determine the taste and flavor of plum fruit. However, metabolism of organic acid and sugar is not fully understood during the development of plum fruit cv. 'Furongli'. RESULTS: Mature fruit of 'Furongli' has the highest content of anthocyanins and the lowest content of total phenol compounds and flavonoids. Malate is the predominant organic acid anion in 'Furongli' fruit, followed by citrate and isocitrate. Glucose was the predominant sugar form, followed by fructose and sucrose. Correlation analysis indicated that malate content increased with increasing phosphoenolpyruvate carboxylase (PEPC) activity and decreasing nicotinamide adenine dinucleotide-malate dehydrogenase (NAD-MDH) activity. Citrate and isocitrate content increased with increasing PEPC and aconitase (ACO) activities, respectively. Both acid invertase and neutral invertase had higher activities at the early stage than later stage of fruit development. Fructose content decreased with increasing phosphoglucoisomerase (PGI) activity, whereas glucose content increased with decreasing hexokinase (HK) activity. CONCLUSION: Dynamics in organic acid anions were not solely controlled by a single enzyme but regulated by the integrated activity of enzymes such as nicotinamide adenine dinucleotide phosphate-malic enzyme (NADP-ME), NAD-ME, PEPC, ACO and NADP-isocitrate dehydrogenase. Sugar metabolism enzymes such as PGI, invertase and HK may play vital roles in the regulation of individual sugar metabolic processes. © 2018 Society of Chemical Industry.

Insights into Resistance Mechanisms of Inhibitors to Mps1 C604Y Mutation via a Comprehensive Molecular Modeling Study.

Mono-polar spindle 1 (Mps1/TTK) represents a protein kinase reported to be vital for cell division processes and is generally regarded as an attractive target for the treatment of hepatocellular carcinoma, breast carcinoma, and colon cancer. However, the C604Y mutation has been linked to acquired resistance. Recently, three potential small-molecule inhibitors of Mps1 (i.e., reversine, NMS-P715, and its derivative Cpd-5) were reported for the C604Y mutation that exhibit significant resistance to NMS-P715 and Cpd-5, but retain affinity for reversine. In this study, classical molecular dynamic (MD) simulations, accelerated MD (aMD) simulations, and umbrella sampling (US) simulations were performed to illustrate the resistance mechanisms of inhibitors to Mps1. The classical MD simulations combined with free energy calculations revealed that reversine features similar binding affinity characteristics to both Mps1WT and Mps1C604Y, but both NMS-P715 and Cpd-5 feature much higher binding affinities to Mps1WT than to Mps1C604Y. The major variations were shown to be controlled by electrostatic energy and the conformational change of A-loop-induced entropy increased. The large conformational changes of Mps1C604Y bound to NMS-P715 and Cpd-5 were also observed in aMD simulations. The US simulation results further suggest that reversine and Cpd-5 both exhibit similar dissociation processes from both Mps1WT and Mps1C604Y, but Cpd-5 and NMS-P715 were found to dissociate more easily from Mps1C604Y than from Mps1WT, thus a reduced residence time was responsible for the inhibitors resistance to the C604Y mutation. The physical principles provided by the present study may provide important clues for the discovery and rational design of novel inhibitors to combat the C604Y mutation of Mps1.

Proteomic Analysis of Avian Influenza A (H7N9) Patients within a Family Cluster.

BACKGROUND: To date, there is limited information on the progression of human infections of avian influenza virus A (H7N9). This study investigated differential blood protein profiling of a H7N9-infected family cluster to find a slice of crucial proteins concerning disease attack and virus clearance. MATERIALS AND METHODS: Plasma samples from one family cluster (including one index case and one asymptomatic case) were collected at four time points. The protein profiles were identified by isobaric tagging for relative and absolute quantification-based quantitative differential LC/MS/MS, and their functional annotations were analyzed by PANTHER and STRING tools. RESULTS: A total of 1257 nonredundant proteins were identified from 3027 unique peptides. Three differential protein profiles for each subject were generated by comparing relative protein abundance between samples of each of the first three time points and the last time point. Gene ontology analysis indicated that differential protein profiles for the two cases were mainly enriched in the biological processes of response to stimulus, immunity, blood coagulation, lipid transport, and cell adhesion. Two groups of proteins with an upward or downward expression change according to the postinfection time points were detected for each case. STRING analysis further indicated that the hubs in the network of these time-dependent proteins were mostly apolipoproteins. CONCLUSIONS: Significant perturbation of the response upon viral infection occurred immediately after confirmation of H7N9 virus infection. The differential protein profiles shed further light on distinguishing the index case from the asymptomatic one. Furthermore, apolipoproteins may play an important role in the progression of the disease.

Global dynamics of a delay virus model with recruitment and saturation effects of immune responses.

In this paper, we formulate a virus dynamics model with the recruitment of immune responses, saturation effects and an intracellular time delay. With the help of uniform persistence theory and Lyapunov method, we show that the global stability of the model is totally determined by the basic reproductive number R0. Furthermore, we analyze the effects of the recruitment of immune responses on virus infection by numerical simulation. The results show ignoring the recruitment of immune responses will result in overestimation of the basic reproductive number and the severity of viral infection.

Identification of Candidate Anthocyanin-Related Genes by Transcriptomic Analysis of 'Furongli' Plum (Prunus salicina Lindl.) during Fruit Ripening Using RNA-Seq.

Anthocyanins are important pigments and are responsible for red coloration in plums. However, little is known about the molecular mechanisms underlying anthocyanin accumulation in plum fruits. In this study, the RNA-seq technique was used to analyze the transcriptomic changes during fruit ripening in the red-fleshed plum (Prunus salicina Lindl.) cultivar 'Furongli'. Over 161 million high-quality reads were assembled into 52,093 unigenes and 49.4% of these were annotated using public databases. Of these, 25,681 unigenes had significant hits to the sequences in the NCBI Nr database, 17,203 unigenes showed significant similarity to known proteins in the Swiss-Prot database and 5816 and 8585 unigenes had significant similarity to existing sequences in the Kyoto Encyclopedia of Genes and Genomes and the Cluster of Orthologous Groups databases, respectively. A total of 3548 unigenes were differentially expressed during fruit ripening and 119 of these were annotated as involved in "biosynthesis of other secondary metabolites." Biological pathway analysis and gene ontology term enrichment analysis revealed that 13 differentially expressed genes are involved in anthocyanin biosynthesis. Furthermore, transcription factors such as MYB and bHLH, which may control anthocyanin biosynthesis, were identified through coexpression analysis of transcription factors, and structural genes. Real-time qPCR analysis of candidate genes showed good correlation with the transcriptome data. These results contribute to our understanding of the molecular mechanisms underlying anthocyanin biosynthesis in plum flesh. The transcriptomic data generated in this study provide a basis for further studies of fruit ripening in plum.

The levels of serine proteases in colon tissue interstitial fluid and serum serve as an indicator of colorectal cancer progression.

The proteins in tissue interstitial fluids (TIFs) can spread into the blood and have been proposed as an ideal material to find blood biomarkers. The colon TIFs were collected from 8-, 13-, 18-, and 22-week ApcMin/+, a typical mouse model of colorectal cancer (CRC), and wild-type mice. iTRAQ-based quantification proteomics was conducted to survey the TIF proteins whose abundance appeared to depend on tumor progression. A total of 46 proteins that exhibited consecutive changes in abundance were identified, including six serine proteases, chymotrypsin-like elastase 1 (CELA1), chymotrypsin-like elastase 2A (CEL2A), chymopasin, chymotrypsinogen B (CTRB1), trypsin 2 (TRY2), and trypsin 4 (TRY4). The observed increases in the abundance of serine proteases were supported in another quantitative evaluation of the individual colon TIFs using a multiple reaction monitor (MRM) assay. Importantly, the increases in the abundance of serine proteases were also verified in the corresponding sera. The quantitative verification of the serine proteases was further extended to the clinical sera, revealing significantly higher levels of CELA1, CEL2A, CTRL/chymopasin, and TRY2 in CRC patients. The receiver operating characteristic analysis illustrated that the combination of CELA1 and CTRL reached the best diagnostic performance, with 90.0% sensitivity and 80.0% specificity. Thus, the quantitative target analysis demonstrated that some serine proteases are indicative of CRC progression.

A Comprehensive Proteomics Analysis Reveals a Secretory Path- and Status-Dependent Signature of Exosomes Released from Tumor-Associated Macrophages.

Exosomes are 30-120 nm-sized membrane vesicles of endocytic origin that are released into the extracellular environment and play roles in cell-cell communication. Tumor-associated macrophages (TAMs) are important constituents of the tumor microenvironment; thus, it is critical to study the features and complex biological functions of TAM-derived exosomes. Here, we constructed a TAM cell model from a mouse macrophage cell line, Ana-1, and performed comparative proteomics on exosomes, exosome-free media, and cells between TAMs and Ana-1. Proteomic analysis between exosome and exosome-free fractions indicated that the functions of exosome dominant proteins were mainly enriched in RNA processing and proteolysis. TAM status dramatically affected the abundances of 20S proteasome subunits and ribosomal proteins in their exosomes. The 20S proteasome activity assay strongly indicated that TAM exosomes possessed higher proteolytic activity. In addition, Ana-1- and TAM-derived exosomes have different RNA profiles, which may result from differential RNA processing proteins. Taken together, our comprehensive proteomics study provides novel views for understanding the complicated roles of macrophage-derived exosomes in the tumor microenvironment.

Ubiquitination of inositol-requiring enzyme 1 (IRE1) by the E3 ligase CHIP mediates the IRE1/TRAF2/JNK pathway.

Deciphering the inositol-requiring enzyme 1 (IRE1) signaling pathway is fundamentally important for understanding the unfolded protein response (UPR). The ubiquitination of proteins residing on the endoplasmic reticulum (ER) membrane has been reported to be involved in the UPR, although the mechanism has yet to be fully elucidated. Using immunoprecipitation and mass spectrometry, IRE1 was identified as a substrate of the E3 ligase CHIP (carboxyl terminus of HSC70-interacting protein) in HEK293 cells under geldanamycin-induced ER stress. Two residues of IRE1, Lys(545) and Lys(828), were targeted for Lys(63)-linked ubiquitination. Moreover, in CHIP knockdown cells, IRE1 phosphorylation and the IRE1-TRAF2 interaction were nearly abolished under ER stress, which may be due to lacking ubiquitination of IRE1 on Lys(545) and Lys(828), respectively. The cellular responses were evaluated, and the data indicated that CHIP-regulated IRE1/TRAF2/JNK signaling antagonized the senescence process. Therefore, our findings suggest that CHIP-mediated ubiquitination of IRE1 contributes to the dynamic regulation of the UPR.

[Dexmedetomidine preconditioning protects isolated rat hearts against ischemia/reperfusion injuries and its mechanism].

OBJECTIVE: To investigate the protective effect of dexmedetomidine (Dex) preconditioning against ischemia/reperfusion (I/R) injuries in isolated rat hearts and its relation to mitochondrial permeability transition pore (mPTP) and mitochondrial ATP-sensitive K(+) channel (mitoKATP). METHODS: The hearts of male SD rats were isolated to mount on the Langendorff apparatus and subjected to 30 min global ischemia followed by 120 min reperfusion. The isolated hearts were treated with Dex (10 nmol/L) before ischemia for 15 min. The left ventricular hemodynamic parameters,coronary flow (CF) and the lactate dehydrogenase (LDH) release in the coronary effluent at 5 min reperfusion were measured. The formazan content was assayed to determine the myocardial viability at the end of reperfusion. RESULTS: Compared with normal controls, I/R markedly decreased the left ventricular developed pressure and CF during the whole reperfusion period and the formazan content; while the left ventricular end diastolic pressure and LDH release were significantly increased. Dex preconditioning markedly improved the myocardial viability and cardiac function (P<0.01), which were reversed by the treatment with both atractyloside (20 µmol/L before ischemia), an opener of mPTP, and 5-hydroxydecanoate (100 µmol/L at the beginning of reperfusion), an inhibitor of mitoKATP, for 20 min. CONCLUSION: Dex has protective effect against I/R injuries in isolated rat hearts, which may be related to inhibiting the opening of mPTP at the beginning of reperfusion and activating mitoKATP before ischemia.

[Construction and screening of the artificial miRNA plasmids targeting porcine Toll-like receptor 7 gene].

OBJECTIVE: To construct and screen specific artificial microRNA (amiRNA) expression plasmids targeting porcine Toll-like receptor 7 (TLR7) gene. METHODS: The 1984-2649 bp sequence of the porcine TLR7 cDNA was amplified by RT-PCR and inserted into plasmid pEGFP-N1 to construct the fusion expression vector pTLR7-EGFP. Five amiRNAs targeting porcine TLR7 gene were designed and cloned into pcDNA5-miR to construct the recombinant interfering plasmids pcDNA5-miRTLR7. NIH-3T3 cells were co-transfected with plasmids pTLR7-EGFP and pcDNA5-miRTLR7. The expression levels of amiTLR7 were monitored by RT-PCR and their silencing efficiencies were detected by fluorescent microscopy and flow cytometry. RESULTS: All five amiTLR7s were successfully constructed and could effectively silence the expression of TLR7 gene in NIH-3T3 cells with the inhibition efficiencies ranging from 36.99% to 97.28%, among which amiTLR7-3 had the best interference efficiency. CONCLUSION: The specific artificial amiRNA expression plasmids targeting porcine TLR7 gene have been successfully constructed, and the optimal amiTLR7 with the highest inhibition efficiency has been screened.

Sinapine detection in radish taproot using surface desorption atmospheric pressure chemical ionization mass spectrometry.

Plant research and natural product detection are of sustainable interests. Benefited by direct detection with no sample preparation, sinapine, a bioactive chemical usually found in various seeds of Brassica plants, has been unambiguously detected in radish taproot (Raphanus sativus) tissue using a liquid-assisted surface desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS). A methanol aqueous solution (1:1) was nebulized by a nitrogen sheath gas toward the corona discharge, resulting in charged ambient small droplets, which affected the radish tissue for desorption/ionization of analytes on the tissue surface. Thus, sinapine was directly detected and identified by tandem DAPCI-MS experiments without sample pretreatment. The typical relative standard deviation (RSD) of this method for sinapine detection was 5-8% for six measurements (S/N=3). The dynamic response range was 10(-12)-10(-7) g/cm2 for sinapine on the radish skin surface. The discovery of sinapine in radish taproot was validated by using HPLC-UV methods. The data demonstrated that DAPCI assisted by solvent enhanced the overall efficiency of the desorption/ionization process, enabling sensitive detection of bioactive compounds in plant tissue.