Study on the Structure of Mangrove Polyflavonoid Tannins with MALDI-TOF Mass Spectrometry and NMR

2012 ◽  
Vol 554-556 ◽  
pp. 1988-1993 ◽  
Author(s):  
Liang Liang Zhang ◽  
Yong Mei Wang ◽  
Dong Mei Wu ◽  
Man Xu ◽  
Jia Hong Chen
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Degree Of Polymerization ◽  
Epicatechin Gallate ◽  
Mangrove Species ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Rhizophora Apiculata ◽  
13C Nuclear Magnetic Resonance ◽  
Tof Ms

The properties of polyflavonoid tannins from the mangrove species depend on their structure in terms of monomer units, their mean degree of polymerization and the linkage-type between flavan-3-ol units with a considerable range of structural variation. Polyflavonoid tannins were characterized by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), which were too difficult to be resolved by other techniques. MALDI-TOF mass spectra of polyflavonoid tannins of four mangrove species in Rhizophoraceae, Kandelia candel, Ceriops tagal, Bruguiera cylindrica and Rhizophora apiculata showed as follows: (1) procyanidin oligomers formed by catechin/epicatechin, and catechin-3-O-rhamnoside monomers were present in great proportions; epigallocatechin and epicatechin gallate monomers were not detected; (2) the doubly linked structure of A-type procyanidins were also evident from the mass spectra of K. candel; (3) there were major differences in polyflavonoid tannin structure among mangrove species; and (4) the distribution of tannin oligomers, and the number-average degree of polymerization obtained by MALDI-TOF MS appeared to compare well with the results obtained by 13C nuclear magnetic resonance (NMR) analysis.

scholarly journals Characterization of aliphatic hyperbranched polyesters by MALDI-TOF mass spectrometry

2007 ◽  
Vol 61 (6) ◽  
pp. 333-341
Author(s):  
Jasna Vukovic ◽  
Slobodan Jovanovic ◽  
Manfred Lechner
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Degree Of Polymerization ◽  
Side Reactions ◽  
Maldi Tof Ms ◽  
Hyperbranched Polyesters ◽  
Maldi Tof ◽  
Maldi Tof Mass Spectra ◽  
Tof Ms

In this work, MALDI-TOF mass spectrometry was used for the characterization of aliphatic hyperbranched polyesters (AHBP), synthesized from 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) and di-trimethylolpropane. From the obtained results it was concluded that it was not possible to take complete advantages of MALDI-TOF MS in this particular case, since the AHBP used in this work were polydisperse. The intensity of the signals from the high mass tail of these samples (pseudo generation higher than four) was underestimated and insufficient to distinguish it from the baseline and to use it for the analysis of the spectra. As a consequence of that, lower values of the Mn were obtained. At the same time, Mw were also underestimated, which led to very low values of the polydispersity index. On the other hand, it was possible to obtain molar masses of individual molecules from the MALDI-TOF mass spectra of AHBP and to qualitatively determine the extent of cyclization (side reactions) at each degree of polymerization. Using the adequate set of equations and results obtained from MALDI-TOF mass spectra of AHBP, every signal from the spectra was identified. The obtained results show that formation of poly(bis-MPA), intramolecular esterification and intramolecular etherification occurred as side reactions during the synthesis of these polyesters. The relative amount of the cycles increases with the number of pseudo generation (from the second up to the fifth pseudo generation). It was also observed that the relative proportion of the signals which represent cyclic structures increases with the increasing degree of polymerization. In this work the basic principles of MALDI-TOF MS are also presented, as well as, a review of adequate published articles.

scholarly journals Understanding the chemical basis for the preferential ionization of specific biomolecules in mass spectrometry analysis of microbial cells

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Mass Spectrometry Analysis ◽  
Chemical Pretreatment ◽  
Maldi Tof Ms ◽  
Spectrometry Analysis ◽  
Chemical Basis ◽  
Maldi Tof ◽  
Different Types ◽  
Tof Ms

Mass spectrometry-enabled microbial identification has successfully demonstrated the feasibility of using profiled biomolecules for identifying microorganisms based on a chemometric or proteome database search approach. However, mechanisms driving the preferential ionization and detection of particular biomolecules in various types of mass spectrometry remain poorly understood. Specifically, mass spectra obtained from different microbial species remain poorly annotated with respect to the specific types of biomolecules accounting for the peaks. For example, while ribosomal proteins are known to be a significant class of biomolecules that could partially account for the profiled mass peaks in mass spectra of microorganisms, other classes of proteins and biomolecules remain poorly annotated. This raises the important question of how different mass spectrometry approaches ionize different types of biomolecules from a cellular matrix. Specifically, mass spectra of microorganisms reveal that only a couple of mass peaks could capture the phylogeny of a species. However, the proteome of a cell is much larger and more complicated, and yet is not fully profiled by different types of mass spectrometry methods. For example, electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could only provide a small snapshot of the entire bacterial proteome. It could be argued that different mass spectrometry methods provide complementary views of a particular proteome. However, the question remains, how do proteins and biomolecules interact with the different sample preparation and mass spectrometry analysis methods for generating an ion cloud for separation in a mass spectrometer? Thus, efforts could be directed towards understanding how different types of proteins could be preferentially ionized by MALDI-TOF MS. Specifically, different reagents could be used to perform chemical pretreatment on the proteome, which would subsequently be analyzed by mass spectrometry. Thus, a correlative map between types of chemical pretreatment used and the corresponding mass spectra could be obtained. Collectively, knowledge gleaned from the research would illuminate the chemical basis by which specific biomolecules are preferentially ionized under particular conditions, which would inform the development of strategies for increasing the subset of biomolecules ionized from a cellular proteome. Such chemical rules would also aid in the interpretation of mass spectra obtained, particularly in understanding the biological context of the experiment. Overall, the key goal of this research is to help answer the question: what is the biological basis and context of the mass spectrum obtained from cells?

scholarly journals A novel and rapid approach to yeast differentiation using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry

2003 ◽  
Vol 17 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Richard E. Sherburn ◽  
Richard O. Jenkins
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Matrix-assisted laser desorption/ionisation time of flight mass spectrometry (MALDI-TOF-MS) was investigated as a method for the rapid identification of yeast cells. Following pretreatment of yeast samples with a cell wall digesting enzyme (lyticase), distinct and reproducible mass spectra over them/zrange 2,000 to 16,000 were obtained by MALDI-TOF-MS. Using an optimised procedure, characteristic mass spectra that distinguished between Candida spp. and between strains of Saccharomyces cerevisiae were produced. The approach offers the potential for rapid differentiation of yeasts in clinical diagnosis and in the fermentation industries.

scholarly journals Discrimination of Bacillus cereus Group Members by MALDI-TOF Mass Spectrometry

2021 ◽  
Vol 9 (6) ◽  
pp. 1202
Author(s):  
Viviana Manzulli ◽  
Valeria Rondinone ◽  
Alessandro Buchicchio ◽  
Luigina Serrecchia ◽  
Dora Cipolletta ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Bacillus Cereus ◽  
Mass Spectra ◽  
Critical Time ◽  
Principal Component ◽  
Etiologic Agent ◽  
Bacillus Cereus Group ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Matrix-Assisted Laser Desorption/Ionization Time Of Flight Mass Spectrometry (MALDI-TOF MS) technology is currently increasingly used in diagnostic laboratories as a cost effective, rapid and reliable routine technique for the identification and typing of microorganisms. In this study, we used MALDI-TOF MS to analyze a collection of 160 strains belonging to the Bacillus cereus group (57 B. anthracis, 49 B. cereus, 1 B. mycoides, 18 B. wiedmannii, 27 B. thuringiensis, 7 B. toyonensis and 1 B. weihenstephanensis) and to detect specific biomarkers which would allow an unequivocal identification. The Main Spectra Profiles (MSPs) were added to an in-house reference library, expanding the current commercial library which does not include B. toyonensis and B. wiedmannii mass spectra. The obtained mass spectra were statistically compared by Principal Component Analysis (PCA) that revealed seven different clusters. Moreover, for the identification purpose, were generated dedicate algorithms for a rapid and automatic detection of characteristic ion peaks after the mass spectra acquisition. The presence of specific biomarkers can be used to differentiate strains within the B. cereus group and to make a reliable identification of Bacillus anthracis, etiologic agent of anthrax, which is the most pathogenic and feared bacterium of the group. This could offer a critical time advantage for the diagnosis and for the clinical management of human anthrax even in case of bioterror attacks.

scholarly journals Understanding the chemical basis for the preferential ionization of specific biomolecules in mass spectrometry analysis of microbial cells

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Mass Spectrometry Analysis ◽  
Chemical Pretreatment ◽  
Maldi Tof Ms ◽  
Spectrometry Analysis ◽  
Chemical Basis ◽  
Maldi Tof ◽  
Different Types ◽  
Tof Ms

Mass spectrometry-enabled microbial identification has successfully demonstrated the feasibility of using profiled biomolecules for identifying microorganisms based on a chemometric or proteome database search approach. However, mechanisms driving the preferential ionization and detection of particular biomolecules in various types of mass spectrometry remain poorly understood. Specifically, mass spectra obtained from different microbial species remain poorly annotated with respect to the specific types of biomolecules accounting for the peaks. For example, while ribosomal proteins are known to be a significant class of biomolecules that could partially account for the profiled mass peaks in mass spectra of microorganisms, other classes of proteins and biomolecules remain poorly annotated. This raises the important question of how different mass spectrometry approaches ionize different types of biomolecules from a cellular matrix. Specifically, mass spectra of microorganisms reveal that only a couple of mass peaks could capture the phylogeny of a species. However, the proteome of a cell is much larger and more complicated, and yet is not fully profiled by different types of mass spectrometry methods. For example, electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) could only provide a small snapshot of the entire bacterial proteome. It could be argued that different mass spectrometry methods provide complementary views of a particular proteome. However, the question remains, how do proteins and biomolecules interact with the different sample preparation and mass spectrometry analysis methods for generating an ion cloud for separation in a mass spectrometer? Thus, efforts could be directed towards understanding how different types of proteins could be preferentially ionized by MALDI-TOF MS. Specifically, different reagents could be used to perform chemical pretreatment on the proteome, which would subsequently be analyzed by mass spectrometry. Thus, a correlative map between types of chemical pretreatment used and the corresponding mass spectra could be obtained. Collectively, knowledge gleaned from the research would illuminate the chemical basis by which specific biomolecules are preferentially ionized under particular conditions, which would inform the development of strategies for increasing the subset of biomolecules ionized from a cellular proteome. Such chemical rules would also aid in the interpretation of mass spectra obtained, particularly in understanding the biological context of the experiment. Overall, the key goal of this research is to help answer the question: what is the biological basis and context of the mass spectrum obtained from cells?

scholarly journals Diagnostic accuracy of MALDI-TOF mass spectrometry for the direct identification of clinical pathogens from urine

Open Medicine ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 266-273
Author(s):  
Min Tang ◽  
Jia Yang ◽  
Ying Li ◽  
Luhua Zhang ◽  
Ying Peng ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Likelihood Ratio ◽  
Meta Analysis ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Urine Samples ◽  
Direct Identification ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

AbstractMatrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has become one of the most popular methods for the rapid and cost-effective detection of clinical pathogenic microorganisms. This study aimed to evaluate and compare the diagnostic performance of MALDI-TOF MS with that of conventional approaches for the direct identification of pathogens from urine samples. A systematic review was conducted based on a literature search of relevant databases. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the summary receiver operating characteristic (SROC) curve of the combined studies were estimated. Nine studies with a total of 3920 subjects were considered eligible and included in the meta-analysis. The pooled sensitivity was 0.85 (95% CI 0.79-0.90), and the pooled specificity was 0.93 (95% CI 0.82-0.97). The PLR and NLR were 11.51 (95% CI 4.53-29.26) and 0.16 (95% CI 0.11-0.24), respectively. The area under the SROC curve was 0.93 (95% CI 0.91-0.95). Sensitivity analysis showed that the results of this meta-analysis were stable. MALDI-TOF MS could directly identify microorganisms from urine samples with high sensitivity and specificity.

scholarly journals The Use of MALDI-TOF Mass Spectrometry to Analyze Commensal Oral Yeasts in Nursing Home Residents

2021 ◽  
Vol 9 (1) ◽  
pp. 142
Author(s):  
Jang-Jih Lu ◽  
Hsiu-Jung Lo ◽  
Chih-Hua Lee ◽  
Mei-Jun Chen ◽  
Chih-Chao Lin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nursing Home ◽  
Dna Sequences ◽  
Nursing Home Residents ◽  
Practical Method ◽  
Elderly Subjects ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Oral Yeasts ◽  
Tof Ms

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate method to identify microorganisms in clinical laboratories. This study isolates yeast-like microorganisms in the oral washes that are collected from non-bedridden nursing home residents, using CHROMagar Candida plates, and identifies them using Bruker MALDI-TOF MS. The ribosomal DNA sequences of the isolates are then examined. Three hundred and twenty yeast isolates are isolated from the oral washes. Candida species form the majority (78.1%), followed by Trichosporon/Cutaneotrichosporon species (8.8%). Bruker MALDI-TOF MS gives a high-level confidence, with a log(score) value of ≥1.8, and identifies 96.9% of the isolates. There are six inconclusive results (1.9%), and those sequences are verified as rare clinical species, including Candida ethanolica, Cutaneotrichosporon jirovecii, Exophiala dermatitidis, and Fereydounia khargensis. Almost all of the isolates have a regular color on the CHROMagar Candida plates. If the colonies are grouped by color on the plates, a specific dominant yeast species is present in each color group, except for purple or orange isolates. In conclusion, MALDI-TOF MS is verified as a fast, accurate and practical method to analyze oral yeasts in elderly subjects.

Microorganism idenitfication – stability and correctness of mass spectrometry method (MALDI TOF MS)

2021 ◽  
Vol 56 (4) ◽  
pp. 1-12
Author(s):  
Łukasz Hildebrant ◽  
Urszula Wendt
Keyword(s):  
Mass Spectrometry ◽  
Quality Control ◽  
Control System ◽  
High Stability ◽  
Spectrometry Method ◽  
Maldi Tof Ms ◽  
Mass Spectrometry Method ◽  
Maldi Tof ◽  
Reference Strains ◽  
Tof Ms

Introduction: MALDI TOF MS method is increasingly used in routine microbiological diagnostics to identify clinical strains. The result of the identification test is based on the measurement of the mass, charge and flight time of the protein ions. This makes it possible to monitor and supervise the method using a numerical score developed with statistical techniques. Aim: The study aimed to determine the stability and correctness of the mass spectrometry method. Materials and methods: To evaluate the characteristics of the method, microbial identification tests were performed using reference strains. All tests were performed as part of the MALDI TOF MS internal quality control system. Results: All reference strains (100%) were correctly identified to the species level, although the score values were not always within the reliability criteria of the results established by the producer. It was found that the mean values of the score were from 2.000 – 2.299 (49.2%) and 2.300 – 3.000 (50.0%). The coefficient of variation for control tests performed in the consecutive years ranged from 5.18 – 6.56%, which evidence of the high stability of the method. For individual species, reproducibility precision over the 8 years ranged from 2.89% (n = 13) for Enterococcus faecalis ATCC 51299 to 7.02% (n = 28) for Klebsiella pneumoniae ATCC 700603, which proves the high precision of measurements. Conclusions: The mass spectrometry method is characterized by very high stability and correctness. The intra-laboratory quality control system using reference strains is a useful tool for monitoring and supervising the method and laboratory personnel competency performing identification tests during routine microbiological work.

scholarly journals Detection of Structural and Conformational Changes in ALS-Causing Mutant Profilin1 With Hydrogen/Deuterium Exchange Mass Spectrometry and Bioinformatics Techniques

2021 ◽  
Author(s):  
Ahmad Shahir Sadr ◽  
zahra abdollahpour ◽  
Atousa Aliahmadi ◽  
Changiz Eslahchi ◽  
Mina Nekouei ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Conformational Changes ◽  
Docking Simulation ◽  
Hydrogen Deuterium Exchange ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Hydrogen Deuterium ◽  
Tof Ms

Abstract The hydrogen/deuterium exchange (HDX) is a reliable method to survey the dynamic behavior of proteins and epitope mapping. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is a quantifying tool to assay for HDX in the protein of interest. We combined HDX-MALDI-TOF MS and molecular docking/MD simulation to identify accessible amino acids and analyze their contribution in the structural changes of profilin1 (PFN1). The molecular docking/MD simulations are computational tools for enabling the analysis of the type of amino acids that may be involved via HDX identified under the lowest binding energy condition. Glycine to Valine amino acid (G117V) substitution mutation is linked to amyotrophic lateral sclerosis (ALS). This mutation is found to be in the actin-binding site of PFN1 and prevents the dimerization/polymerization of actin and invokes a pathologic toxicity that leads to ALS. In this study, we sought to understand the PFN1 protein dynamic behavior using purified wild type and mutant PFN1 proteins. The data obtained from HDX-MALDI-TOF MS for PFN1WT and PFN1G117V at various time intervals, from seconds to hours, revealed multiple peaks corresponding to molecular weights from monomers to multimers. PFN1/Benzaldehyde complexes identified 20 accessible amino acids to HDX that participate in the docking simulation in the surface of WT and mutant PFN1. Consistent results from HDX-MALDI-TOF MS and docking simulation predict candidate amino acid(s) involved in the dimerization/polymerization of PFNG117V. This information may shed critical light on the structural and conformational changes with details of amino acid epitopes for mutant PFN1s’ dimerization, oligomerization, and aggregation.

scholarly journals Development and Validation of an in-House Library of Colombian Candida auris Strains with MALDI-TOF MS to Improve Yeast Identification

2020 ◽  
Vol 6 (2) ◽  
pp. 72 ◽  
Author(s):  
Andrés Ceballos-Garzon ◽  
Daniela Amado ◽  
Norida Vélez ◽  
María José Jiménez-A ◽  
Crescencio Rodríguez ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Candida Auris ◽  
Yeast Identification ◽  
Great Opportunity ◽  
Maldi Tof Ms ◽  
Identification Process ◽  
Clinical Strains ◽  
Maldi Tof ◽  
Development And Validation ◽  
Tof Ms

Background: Candida auris is characterized for having a high genetic variability among species. MALDI-TOF MS library contains spectra from only three strains of C. auris, which makes difficult the identification process and gives low scores at the species level. Our aim was to construct and validate an internal library to improve C. auris identification with Colombian clinical strains. Methods: From 30 clinical strains, 770 mass spectra were obtained for the construction of the database. The validation was performed with 300 strains to compare the identification results in the BDAL and C. auris Colombia libraries. Results: Our library allowed a complete, 100% identification of the evaluated strains and a significant improvement in the scores obtained, showing a better performance compared to the Bruker BDAL library. Conclusions: The strengthening of the database is a great opportunity to improve the scoring and C. auris identification. Library data are available via ProteomeXchange with identifier PXD016387.

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