Application of Matrix-assisted Laser Desorption Ionization Mass Spectrometry in Analysis of Traditional Chinese Medicine：A Comprehensive Review / 中国实验方剂学杂志

Traditional Chinese medicine （TCM）， which owns abundant chemical components and complex action pathways， has been widely recognized in the prevention and treatment of diseases. Some analysis methods have been emerged in order to ensure the quality of TCM and to develop new TCM drugs. Matrix-assisted laser desorption ionization mass spectrometry （MALDI-MS） is a soft ionization mass spectrometric technique with the advantages of high throughput， high sensitivity， low cost and so on. It provides technical support for the molecular level study on TCM. At present， this technique has been used in the field of composition analysis and metabonomics research of TCM， and plays an important role in the identification of Chinese herbal medicines， real-time molecular screening and the construction of metabolic network pathway of active ingredients. Among them， the selection of appropriate matrix and sample preparation technology is the key to ensure the detection effect of MALDI-MS. With the development and optimization of new matrix， the continuous improvement of sample preparation technology and the combination of MALDI-MS with various analytical methods will greatly improve the detection effect. Based on this， this paper discusses the application of MALDI-MS in TCM， including high-throughput detection of active ingredients in TCM， monitoring of the original medicines and their metabolites in vivo， and in situ visualization and characterization of tissue distribution information of active ingredients in TCM. It also discusses the application prospect and existing problems of MALDI-MS in TCM， so as to provide technical support for the identification of active ingredients in TCM， drug utilization and metabolism.

Spatial distribution characteristics of metabolities in rhizome of Paris polyphylla var. yunnanensis: based on MALDI-MSI / 中国中药杂志

In this study, a method was established for in-situ visualization of metabolite distribution in the rhizome of Paris polyphylla var. yunnanensis. To be specific, through matrix-assisted laser desorption/ionization-mass spectrometry imaging(MALDI-MSI), the spatial locations of steroidal saponins, amino acids, organic acids, phytosterols, phytoecdysones, nucleosides, and esters in rhizome of the medicinal plant were directly analyzed, and six unknown compounds with differential distribution in rhizome tissues were identified. The specific procedure is as follows: preparation of rhizome tissue section, matrix screening and optimization, and MALDI-MSI analysis. The results showed that the steroidal saponins were mainly distributed in the central, amino acids in epidermis and cortex, low-molecular-weight organic acids in central epidermis, phytosterols in the epidermis and lateral cortex, the phytoecdysones in epidermis and cortex, nucleosides(uneven distribution) in epidermis and cortex, growth hormones around the epidermis and cortex, particularly outside the cortex, and esters in cortex with unobvious difference among different tissues. In this study, the spatial distribution of meta-bolites in the rhizome of P. polyphylla var. yunnanensis was characterized for the first time. The result can serve as a reference for identifying and extracting endogenous metabolites of P. polyphylla var. yunnanensis, exploring the synthesis and metabolism mechanisms of the metabolites, and evaluating the quality of medicinal materials.

Utility of Conventional Culture and MALDI-TOF MS for Identification of Microbial Communities in Bronchoalveolar Lavage Fluid in Comparison with the GS Junior Next Generation Sequencing System

BACKGROUND: Diverse microbiota exist in the lower respiratory tract. Although next generation sequencing (NGS) is the most widely used microbiome analysis technique, it is difficult to implement NGS in clinical microbiology laboratories. Therefore, we evaluated the performance of conventional culture methods together with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in identifying microbiota in bronchoalveolar lavage (BAL) fluid. METHODS: BAL fluid samples (n=27) were obtained from patients undergoing diagnostic bronchoscopy for lung mass evaluation. Bacterial and fungal culture was performed with conventional media used in clinical microbiology laboratories. On an average, 20 isolated colonies were picked from each agar plate and identified by MALDI-TOF MS. Microbiome analysis using 16S rRNA NGS was conducted for comparison. RESULTS: Streptococcus spp. and Neisseria spp. were most frequently cultured from the BAL fluid samples. In two samples, Enterobacteriaceae grew predominantly on MacConkey agar. Actinomyces and Veillonella spp. were commonly identified anaerobes; gut bacteria, such as Lactobacillus, Bifidobacterium, and Clostridium, and fungi were also isolated. NGS revealed more diverse bacterial communities than culture, and Prevotella spp. were mainly identified solely by NGS. Some bacteria, such as Staphylococcus spp., Clostridium spp., and Bifidobacterium spp., were identified solely by culture, indicating that culture may be more sensitive for detecting certain bacteria. CONCLUSIONS: Culture and NGS of BAL fluid samples revealed common bacteria with some different microbial communities. Despite some limitations, culture combined with MALDI-TOF MS might play a complementary role in microbiome analysis using 16S rRNA NGS.

Distinction of Cells Infected with Respiratory Syncytial Virus by Matrix Assisted Laser Desorption/Ionization Mass Spectrometry / 分析化学

Respiratory syncytial virus (RSV),which is a major cause of lower respiratory tract infections during infancy and childhood,is also an important pathogen for immunosuppression in elder and diseased areas.In order to research the pathogenesis of RSV,the matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS)was used to explore the difference between uninfected cells and virus-infected cells.The result showed that,in the molecular weight range of 5000~10000 Da,there are three component peaks expressed with significant difference in both normal group and infection group.One of the three components was up-regulated (m/z 6154.25) and the other two were down-regulated (m/z 7658.47 and 9259.82) after RSV infection.This result proved the obvious differences between the infected cells and untreated cells.The differential expression may provide a feasible method for RSV disease diagnosis and pathology research,and also provide scientific evidences for research on development of RSV therapeutic drugs.

Comparison of Efficacy of Human Papilloma Virus Genotyping Assays using Restriction Fragment Mass Polymorphism and DNA Chip Analysis in Patients with Abnormal Pap Smear and Uterine Cervical Cancer

BACKGROUND: High-risk human papilloma virus (HPV) infection is the primary cause of cervical cancer; there is a need for more sensitive and reliable methods for HPV genotyping to use as screening tools for early detection and intervention. METHODS: A novel MALDI-TOF MSbased assay, termed Restriction Fragment Mass Polymorphism (RFMP) was developed for multiple HPV genotyping. Its performance was compared with DNA chip technology. The study was based on 164 cases classified as normal (n=40), ASCUS (n=53) and invasive squamous cell carcinoma (SCC, n=71) by a PAP smear and/or cervical colposcopic biopsy. RESULTS: High-risk genotypes were detected in 7.5%, 47.2% and 97.2% in normal, ASCUS and SCC groups by RFMP, and in 20.0%, 41.5% and 90.1% using DNA chip technology, respectively. The results showed substantial concordance, with a kappa coefficient of 0.688, between the methods. Diagnostic sensitivity and specificity for cervical cancer were found to be 97.2% and 92.2% with RFMP and 90.1% and 80.0% using DNA chip microarrays. CONCLUSIONS: RFMP and DNA chip technologies were shown to be reliable methods for HPV genotyping with a high concordance. The improved sensitivity and specificity should make RFMP a viable option for the management of women with cervical neoplastic lesions.

Identification of a Marker Protein for Cardiac Ischemia and Reperfusion Injury by Two-Dimensional Gel Electrophoresis and Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

The purpose of the present study was to evaluate the expression of cardiac marker protein in rabbit cardiac tissue that was exposed to ischemic preconditioning (IPC), or ischemiareperfusion injury (IR) using two-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). We compared 2DE gels of control (uninjured) cardiac tissue with those of IPC and IR cardiac tissue. Expression of one protein was detected in IR heart tissue, however the protein was not detected in the samples of control and IPC tissue. To further characterize the detected protein molecule, the protein in the 2D gel was isolated and subjected to trypsin digestion, followed by MALDI-MS. The protein was identified as myoglobin, which was confirmed also by Western blot analysis. These results are consistent with previous studies of cardiac markers in ischemic hearts, indicating myoglobin as a suitable marker of myocardial injury. In addition, the present use of multiple techniques indicates that proteomic analysis is an appropriate means to identify cardiac markers in studies of IPC and IR.