Visualizing the spatial distribution of metabolites in Clausena lansium (Lour.) skeels using matrix-assisted laser desorption/ionization mass spectrometry imaging

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2021-2022

The use of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry for the analysis of carbohydrates and glycoconjugates is a well-established technique and this review is the 12th update of the original article published in 1999 and brings coverage of the literature to the end of 2022. As with previous review, this review also includes a few papers that describe methods appropriate to analysis by MALDI, such as sample preparation, even though the ionization method is not MALDI. The review follows the same format as previous reviews. It is divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of computer software for structural identification. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other general areas such as medicine, industrial processes, natural products and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. MALDI is still an ideal technique for carbohydrate analysis, particularly in its ability to produce single ions from each analyte and advancements in the technique and range of applications show little sign of diminishing.

Spatial metabolomics in mental disorders and traditional Chinese medicine: a review

Spatial metabolomics is an emerging technology that integrates mass spectrometry imaging (MSI) with metabolomics, offering a novel visual perspective for traditional metabolomics analysis. This technology enables in-depth analysis in three dimensions: qualitative, quantitative, and localization of metabolites. Spatial metabolomics precisely reflects the characteristics of metabolic network changes in metabolites within entire tissues or specific micro-regions. It provides a detailed understanding of the pharmacodynamic material basis and mechanisms of action. These capabilities suggest that spatial metabolomics can offer significant technical support for studying the complex pathophysiology of mental disorders. Although the mechanisms underlying mental disorders have been reviewed multiple times, this paper provides a comprehensive comparison between traditional metabolomics and spatial metabolomics. It also summarizes the latest progress and challenges of applying spatial metabolomics to the study of mental disorders and traditional Chinese medicine.

Insights into Tissue-Specific Specialized Metabolism in Wampee (Clausena lansium (Lour.) Skeels) Varieties

Wampee (Clausena lansium (Lour.) Skeels) has natural bioactive components with diverse health benefits, but its detailed metabolism and tissue distribution are not fully understood. Here, widely targeted metabolomics analysis methods were employed to analyze the wampee fruit (peel, pulp, and seed) of 17 different varieties. A total of 1286 metabolites were annotated, including lipids, flavonoids, polyphenols, carbazole alkaloids, coumarins, and organic acids, among others. The quantitative analysis and matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) analysis indicated remarkable variations in metabolite categories and content in the peel, pulp, and seed of wampee fruit. Additionally, the difference analysis found that the metabolic components of peel contributed dominantly to the differences among varieties, and 7 potential biomarkers were identified. In this study, a comprehensive metabolome landscape of wampee fruit was established, which provided important information for the isolation and identification of functional components, food industry application, and nutritional improvement breeding.

Mass Spectrometry-Imaging Analysis of Active Ingredients in the Leaves of Taxus cuspidata

BACKGROUND

Taxus cuspidata is an endangered evergreen conifer mainly found in Northeast Asia. In addition to the well-known taxanes, several active ingredients were detected in the leaves of T. cuspidata. However, the precise spatial distribution of active ingredients in the leaves of T. cuspidata is largely unknown.

RESULTS

in the present study, timsTOF flex MALDI-2 analysis was used to uncover the accumulation pattern of active ingredients in T. cuspidata leaves. In total, 3084 ion features were obtained, of which 944 were annotated according to the mass spectrometry database. The principal component analysis separated all of the detected metabolites into four typical leaf tissues: mesophyll cells, upper epidermis, lower epidermis, and vascular bundle cells. Imaging analysis identified several leaf tissues that specifically accumulated active ingredients, providing theoretical support for studying the regulation mechanism of compound biosynthesis. Furthermore, the relative accumulation levels of each identified compound were analyzed. Two flavonoid compounds, ligustroflavone and Morin, were identified with high content through quantitative analysis of the ion intensity.

CONCLUSIONS

our data provides fundamental information for the protective utilization of T. cuspidata.

Applications of mass spectrometry imaging in botanical research

Mass spectrometry imaging (MSI) serves as a valuable tool enabling researchers to scrutinize various compounds, peptides, and proteins within a sample, providing detailed insights at both elemental and molecular levels. This innovative technology transforms information obtained from a mass spectrometer- encompassing ionic strength, mass-to-charge ratio, and ionized molecule coordinates-within a defined region into a pixel-based model. Consequently, it reconstructs the spatial distribution of ions, allowing for a comprehensive understanding of molecular landscapes. The significance of MSI lies in its ability to offer multiple advantages, including straightforward sample preparation and remarkable sensitivity, all achieved without the necessity for labeling. Particularly in the realm of plant biology, MSI finds frequent application in examining the distribution of target metabolites and other components within plant tissues. This review delves into the fundamental principles, distinguishing features, merits, and applications of three prominent MSI technologies. Furthermore, we aim to assist readers in navigating the utilization of MSI in their plant biology research by discussing primary challenges, proposing potential solutions, and elucidating future prospects associated with this cutting-edge technology.

Structural characterization of a water-soluble acidic polysaccharide CSP-IV with potential anticoagulant activity from fruit pulp of Clausena lansium (Lour.) Skeels Guifei

Four main water-soluble wampee fruit pulp polysaccharides, named CSP-I, CSP-II, CSP-III and CSP-IV, were isolated from Clausena lansium (Lour.) Skeels Guifei, therein CSP-IV content was higher than the others. All components possess certain anticoagulant activity demonstrated by prolonged activated partial thromboplastin time, especially CSP-IV, which suggests that CSP-IV plays anticoagulant effect through disturbing intrinsic coagulation pathway. The wampee polysaccharide CSP-IV with Mw of 510.1 kDa was mainly composed of Gal, Ara and GalA. Backbone of CSP-IV contains Gal, Ara and GalA, two kinds of side chains contain one monosaccharide Gal or Ara, both branch on Gal residue of backbone. CSP-IV has no the conformation of triple helix demonstrated by Congo red test. These results showed that CSP-IV is an acidic polysaccharide with potential anticoagulant activity via targeting intrinsic coagulation pathway.

Mass spectrometry imaging and single-cell transcriptional profiling reveal the tissue-specific regulation of bioactive ingredient biosynthesis in Taxus leaves

Taxus leaves provide the raw industrial materials for taxol, a natural antineoplastic drug widely used in the treatment of various cancers. However, the precise distribution, biosynthesis, and transcriptional regulation of taxoids and other active components in Taxus leaves remain unknown. Matrix-assisted laser desorption/ionization-mass spectrometry imaging analysis was used to visualize various secondary metabolites in leaf sections of Taxus mairei, confirming the tissue-specific accumulation of different active metabolites. Single-cell sequencing was used to produce expression profiles of 8846 cells, with a median of 2352 genes per cell. Based on a series of cluster-specific markers, cells were grouped into 15 clusters, suggesting a high degree of cell heterogeneity in T. mairei leaves. Our data were used to create the first Taxus leaf metabolic single-cell atlas and to reveal spatial and temporal expression patterns of several secondary metabolic pathways. According to the cell-type annotation, most taxol biosynthesis genes are expressed mainly in leaf mesophyll cells; phenolic acid and flavonoid biosynthesis genes are highly expressed in leaf epidermal cells (including the stomatal complex and guard cells); and terpenoid and steroid biosynthesis genes are expressed specifically in leaf mesophyll cells. A number of novel and cell-specific transcription factors involved in secondary metabolite biosynthesis were identified, including MYB17, WRKY12, WRKY31, ERF13, GT_2, and bHLH46. Our research establishes the transcriptional landscape of major cell types in T. mairei leaves at a single-cell resolution and provides valuable resources for studying the basic principles of cell-type-specific regulation of secondary metabolism.

Ligand-Dependant Selective Synthesis of Mono- and Dialkenylcarbazoles through Rhodium(III)-Catalyzed C-H Alkenylation

The C-H alkenylation of N-acetylcarbazoles proceeds smoothly at the C1-position in the presence of a cationic Cp*Rh(III) catalyst to produce 1-alkenylcarbazoles. The use of a cationic Cp^E Rh(III) catalyst enables further alkenylation to give 1,8-dialkenylcarbazoles. The direct alkenylation procedure in combination with the ready removal of the acetyl directing group provides a straightforward synthetic pathway to 1- and/or 8-alkenyl-N-H-carbazole derivatives. One of 1-alkenyl-N-H-carbazoles obtained by the present C-H alkenylation/deacetylation exhibits solvatochromism.

Key defatting tissue pretreatment protocol for enhanced MALDI MS Imaging of peptide biomarkers visualization in the castor beans and their attribution applications

INTRODUCTION

Castor bean or ricin-induced intoxication or terror events have threatened public security and social safety. Potential resources or materials include beans, raw extraction products, crude toxins, and purified ricin. The traceability of the origins of castor beans is thus essential for forensic and anti-terror investigations. As a new imaging technique with label-free, rapid, and high throughput features, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) has been gradually stressed in plant research. However, sample preparation approaches for plant tissues still face severe challenges, especially for some lipid-rich, water-rich, or fragile tissues. Proper tissue washing procedures would be pivotal, but little information is known until now.

METHODS

For castor beans containing plenty of lipids that were fragile when handled, we developed a comprehensive tissue pretreatment protocol. Eight washing procedures aimed at removing lipids were discussed in detail. We then constructed a robust MALDI-MSI method to enhance the detection sensitivity of RCBs in castor beans.

RESULTS AND DISCUSSION

A modified six-step washing procedure was chosen as the most critical parameter regarding the MSI visualization of peptides. The method was further applied to visualize and quantify the defense peptides, Ricinus communis biomarkers (RCBs) in castor bean tissue sections from nine different geographic sources from China, Pakistan, and Ethiopia. Multivariate statistical models, including deep learning network, revealed a valuable classification clue concerning nationality and altitude.

Mass spectrometry imaging: new eyes on natural products for drug research and development

Natural products (NPs) and their structural analogs represent a major source of novel drug development for disease prevention and treatment. The development of new drugs from NPs includes two crucial aspects. One is the discovery of NPs from medicinal plants/microorganisms, and the other is the evaluation of the NPs in vivo at various physiological and pathological states. The heterogeneous spatial distribution of NPs in medicinal plants/microorganisms or in vivo can provide valuable information for drug development. However, few molecular imaging technologies can detect thousands of compounds simultaneously on a label-free basis. Over the last two decades, mass spectrometry imaging (MSI) methods have progressively improved and diversified, thereby allowing for the development of various applications of NPs in plants/microorganisms and in vivo NP research. Because MSI allows for the spatial mapping of the production and distribution of numerous molecules in situ without labeling, it provides a visualization tool for NP research. Therefore, we have focused this mini-review on summarizing the applications of MSI technology in discovering NPs from medicinal plants and evaluating NPs in preclinical studies from the perspective of new drug research and development (R&D). Additionally, we briefly reviewed the factors that should be carefully considered to obtain the desired MSI results. Finally, the future development of MSI in new drug R&D is proposed.

Anti-inflammatory and anti-apoptotic effects of Shaoyao decoction on X-ray radiation-induced enteritis of C57BL/6 mice

ETHNOPHARMACOLOGICAL RELEVANCE

As a typical heat-clearing prescription, Shaoyao decoction (SYD) has a robust function of clearing viscera heat for the treatment of several intestinal discomfort symptoms. Clinical evidence indicated that it had the potential to cure radiation enteritis. However, its underlying mechanisms remain unclear.

AIM OF THE STUDY

The present study was designed to probe the protective effects and the involved mechanisms of SYD on X-ray radiation-induced enteritis of C57BL/6 mice.

MATERIALS AND METHODS

X-ray irradiation were used to establish the radiation enteritis model. Forty-eight male C57BL/6 mice (20 ± 2 g) were randomly divided into six groups: the control group, model group, dexamethasone group (DEX, 0.12 mg/kg) and SYD groups (0.12, 0.24 and 0.36 g/mL), respectively. All mice (except the control group) were intragastrically administrated for a continuous 7 days. H&E and Masson staining were employed to evaluate the morphological and collagen fibers changes of the colon. ELISA was performed to assess the levels of MDA, SOD, COX, LPS, IL-6, IL-1β and TNF-α in serum. Moreover, TUNEL fluorescence, western blot and qRT-PCR were used to detect the levels of apoptosis-related proteins and genes of Dclk-1, ATM, MRE-11, Bcl-2, Bax, Caspase-3, and Cyto-c. Furthermore, immunofluorescent staining was applied to detect the protein levels of p53 and Claudin-1 in colon.

RESULTS

Treatment with SYD decreased the exfoliated and necrotic epithelial cells and prevent the proliferate from damaged fibrous tissue in the crypt layer of mucos. The levels of serum peroxidation and pro-inflammatory cytokines (MDA, COX, LPS, IL-6, IL-1β and TNF-α) were obviously inhibited, while SOD sharply increased in serum after administration. Moreover, SYD can significantly ameliorate the apoptosis of colon cells, evidenced by the reduced positive expression of TUNEL staining. Meanwhile, the results of qRT-PCR and western blot demonstrated that SYD can dramatically stimulate the expression of genes and proteins Dclk-1, ATM and MRE-11, thus promoting the expression of mitochondrial pro-apoptotic proteins Bax, Caspase-3 and Cyto-c, while increasing the level of anti-apoptotic protein Bcl-2. Furthermore, immunofluorescence revealed that SYD can notably decreased the protein level of p53 while reverse the reduction of Claudin-1.

CONCLUSIONS

These results indicated that radiation enteritis in C57BL/6 mice can be ameliorated by treatment with SYD. The potential protection mechanisms may be involved in ameliorating tissue fibrosis by decreasing inflammatory and apoptotic events.