scholarly journals Development of an inexpensive matrix-assisted laser desorption—time of flight mass spectrometry method for the identification of endophytes and rhizobacteria cultured from the microbiome associated with maize

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11359
Author(s):  
Michael G. LaMontagne ◽  
Phi L. Tran ◽  
Alexander Benavidez ◽  
Lisa D. Morano
Keyword(s):  
Mass Spectra ◽  
Heterotrophic Bacteria ◽  
Learning Algorithm ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Rrna Gene ◽  
Maldi Tof ◽  
Desorption Time ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Many endophytes and rhizobacteria associated with plants support the growth and health of their hosts. The vast majority of these potentially beneficial bacteria have yet to be characterized, in part because of the cost of identifying bacterial isolates. Matrix-assisted laser desorption-time of flight (MALDI-TOF) has enabled culturomic studies of host-associated microbiomes but analysis of mass spectra generated from plant-associated bacteria requires optimization. In this study, we aligned mass spectra generated from endophytes and rhizobacteria isolated from heritage and sweet varieties of Zea mays. Multiple iterations of alignment attempts identified a set of parameters that sorted 114 isolates into 60 coherent MALDI-TOF taxonomic units (MTUs). These MTUs corresponded to strains with practically identical (>99%) 16S rRNA gene sequences. Mass spectra were used to train a machine learning algorithm that classified 100% of the isolates into 60 MTUs. These MTUs provided >70% coverage of aerobic, heterotrophic bacteria readily cultured with nutrient rich media from the maize microbiome and allowed prediction of the total diversity recoverable with that particular cultivation method. Acidovorax sp., Pseudomonas sp. and Cellulosimicrobium sp. dominated the library generated from the rhizoplane. Relative to the sweet variety, the heritage variety c ontained a high number of MTUs. The ability to detect these differences in libraries, suggests a rapid and inexpensive method of describing the diversity of bacteria cultured from the endosphere and rhizosphere of maize.

scholarly journals Assessment by Matrix-Assisted Laser Desorption – Time of Flight Mass Spectrometry of the Diversity of Endophytes and Rhizobacteria Cultured from the Maize Microbiome

2020 ◽  
Author(s):  
Michael G. LaMontagne ◽  
Phi L. Tran ◽  
Alexander Benavidez ◽  
Lisa D. Morano
Keyword(s):  
Mass Spectra ◽  
Heterotrophic Bacteria ◽  
Learning Algorithm ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Rrna Gene ◽  
Maldi Tof ◽  
Desorption Time ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

AbstractMany endophytes and rhizobacteria associated with plants support the growth and health of their hosts. The vast majority of these potentially beneficial bacteria have yet to be cultured, in part because of the cost of identifying bacterial isolates. Matrix-assisted laser desorption – time of flight (MALDI-TOF) has enabled high throughput “culturomics” studies of host-associated microbiomes but analysis of mass spectra generated from plant-associated bacteria requires optimization. In this study, we aligned mass spectra generated from endophytes and rhizobacteria isolated from heritage and sweet varieties of Zea mays. Multiple iterations of alignment attempts identified a set of parameters that sorted 114 isolates into 60 coherent MALDI-TOF taxonomic units (MTUs). These MTUs corresponded to strains with practically identical (> 99%) 16S rRNA gene sequences. Mass spectra were used to successfully train a machine learning algorithm that perfectly classified isolates. The 60 MTUs provided > 70 % coverage of aerobic, heterotrophic bacteria readily cultured with nutrient rich media from the maize microbiome and allowed prediction of the total diversity recoverable with that particular cultivation method. Acidovorax sp., Pseudomonas sp. and Cellulosimicrobium sp. dominated the library generated from the rhizoplane and the heritage variety contained a relatively high number of MTUs specific to that niche. This suggests a rapid, inexpensive method of describing the types of bacteria cultured from niches within maize microbiomes and the coverage achieved with a cultivation strategy.

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 Characterization of Potential Protein Biomarkers for Major Depressive Disorder Using Matrix-Assisted Laser Desorption Ionization/Time-of-Flight Mass Spectrometry

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4457
Author(s):  
Chieh-Hsin Lin ◽  
Hung Su ◽  
Chung-Chieh Hung ◽  
Hsien-Yuan Lane ◽  
Jentaie Shiea
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Healthy Controls ◽  
Laser Desorption Ionization ◽  
Major Depressive ◽  
Ionization Time ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) mass spectrometry is a sensitive analytical tool for characterizing various biomolecules in biofluids. In this study, MALDI-TOF was used to characterize potential plasma biomarkers for distinguishing patients with major depressive disorder (MDD) from patients with schizophrenia and healthy controls. To avoid interference from albumin—the predominant protein in plasma—the plasma samples were pretreated using acid hydrolysis. The results obtained by MALDI-TOF were also validated by electrospray ionization-quadrupole time-of-flight (ESI-QTOF) mass spectrometry. The analytical results were further treated with principal component analysis (PCA), hierarchical clustering analysis (HCA), and receiver operating characteristic (ROC) curve analysis. The statistical analyses showed that MDD patients could be distinguished from schizophrenia patients and healthy controls by the lack of apolipoprotein C1 (Apo C1), which, in fact, was detected in healthy controls and schizophrenia patients. This protein is suggested to be a potential plasma biomarker for distinguishing MDD patients from healthy controls and schizophrenia patients. Since sample preparation for MALDI-TOF is very simple, high-throughput plasma apolipoprotein analysis for clinical purposes is feasible.

scholarly journals Performance of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identifying Clinical Malassezia Isolates

2016 ◽  
Vol 55 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Julie Denis ◽  
Marie Machouart ◽  
Florent Morio ◽  
Marcela Sabou ◽  
Catherine Kauffmann-LaCroix ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Content Type ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

ABSTRACT The genus Malassezia comprises commensal yeasts on human skin. These yeasts are involved in superficial infections but are also isolated in deeper infections, such as fungemia, particularly in certain at-risk patients, such as neonates or patients with parenteral nutrition catheters. Very little is known about Malassezia epidemiology and virulence. This is due mainly to the difficulty of distinguishing species. Currently, species identification is based on morphological and biochemical characteristics. Only molecular biology techniques identify species with certainty, but they are time-consuming and expensive. The aim of this study was to develop and evaluate a matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) database for identifying Malassezia species by mass spectrometry. Eighty-five Malassezia isolates from patients in three French university hospitals were investigated. Each strain was identified by internal transcribed spacer sequencing. Forty-five strains of the six species Malassezia furfur , M. sympodialis , M. slooffiae , M. globosa , M. restricta , and M. pachydermatis allowed the creation of a MALDI-TOF database. Forty other strains were used to test this database. All strains were identified by our Malassezia database with log scores of >2.0, according to the manufacturer's criteria. Repeatability and reproducibility tests showed a coefficient of variation of the log score values of <10%. In conclusion, our new Malassezia database allows easy, fast, and reliable identification of Malassezia species. Implementation of this database will contribute to a better, more rapid identification of Malassezia species and will be helpful in gaining a better understanding of their epidemiology.

The Identification of Microbial Pathogens Using Matrix Assisted Laser Desorption Ionization Time of Flight in Medical Intensive Care Unit Beni-Suef University Hospital

2021 ◽  
Vol 30 (3) ◽  
pp. 65-69
Author(s):  
Marwa N. Mohamed ◽  
Ahmed F. Azmy ◽  
Ehab M. Fahmy ◽  
Mervat G. Elanany ◽  
Nesreen M. Kamel
Keyword(s):  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Microbial Identification ◽  
Desorption Ionization ◽  
Maldi Tof ◽  
Kappa Agreement ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Background: Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) is a novel technique for identification of microbes. This new method led to a new era in microbial identification because of its rapid, accurate, valid, simple and relatively decreased cost. Objectives: The aim of this study was identification of predominant pathogens by MALDI-TOF technique. Methodology: Pathogens were identified by both conventional methods and MALDI-TOF. Results: From July till December 2018, predominant pathogens were Klebsiella pneumoniae (21%), Pseudomonas aeroguinosa and Candida each constitutes (17%), E-coli (10%), Staph. aureus (9%), Acinetobacter (9%). Identification of isolates (from September to December 2018) by MALDI-TOF revealed a total agreement of (94.1%) with conventional method at genus level, (88.2%) at level of species. Kappa agreement revealed almost perfect correlation between both techniques. Conclusion: The MALDI-TOF results might suggest that its’ usage may be dependable for microbiological identification.

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