Sample preparation and culture condition effects on MALDI‐TOF MS identification of bacteria: A review

Abstract Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is now used as a routine technique for the fast and reliable identification of fungi at the species level and, currently, it represents an important phenotypic methodology based on proteomic profiles. The main limitations to MALDI-TOF MS for fungal identification are related to sample quality (e.g. quality of biological material such as rigidity or pigmentation of cell walls), sample preparation (e.g. the myriad of sample preparation methodologies that deliver different data sets to different MALDI-TOF MS databases) and the databases themselves (e.g. the 'black-box' commercial databases). This chapter presents an overview and discussion of the use of MALDI-TOF MS for fungal identification. The major known limitations of the technique for fungal taxonomy, and how to overcome these, are also discussed.

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Testing the Applicability of MALDI-TOF MS as an Alternative Stock Identification Method in a Cryptic Species Complex

Molecules ◽

10.3390/molecules25143214 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3214

Author(s):

Gabor Maasz ◽

Zita Zrínyi ◽

Istvan Fodor ◽

Nóra Boross ◽

Zoltán Vitál ◽

...

Keyword(s):

Sample Preparation ◽

Cryptic Species ◽

Species Complex ◽

Intraspecific Variability ◽

Clove Oil ◽

Term Survival ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Ms Analysis ◽

Tof Ms

Knowledge of intraspecific variability of a certain species is essential for their long-term survival and for the development of conservation plans. Nowadays, molecular/genetic methods are the most frequently used for this purpose. Although, the Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) technique has become a promising alternative tool to specify intraspecific variability, there is a lack of information about the limitations of this method, and some methodological issues need to be resolved. Towards this goal, we tested the sensitivity of this method on an intraspecific level, using genetically identified individuals of a cryptic fish species complex collected from five distinct populations. Additionally, some methodologic issues, such as the effect of (1) delayed sample preparation, (2) clove oil anaesthetization, and (3) different tissue types (muscle, and brain) were investigated using the MS analysis results. Our results show that the delayed sample preparation has a fundamental effect on the result of MS analysis, while at the same time the clove oil did not affect the results considerably. Both the brain and muscle samples were usable for cryptic species identification, but in our opinion this method has limited applicability for population-level segregation. The application of MALDI-TOF MS to the exploitable toolkit of phylogenetic and taxonomic researches could be used to broaden conclusions.

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Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for Rapid Identification of Bacteria in Processed Soybean Products

Journal of Food Research ◽

10.5539/jfr.v2n3p104 ◽

2013 ◽

Vol 2 (3) ◽

pp. 104 ◽

Cited By ~ 2

Author(s):

Yuko Furukawa ◽

Mitsuru Katase ◽

Kazunobu Tsumura

Keyword(s):

Laser Desorption ◽

Rapid Identification ◽

Bacterial Cells ◽

Laser Desorption Ionization ◽

Ionization Time ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Flight Mass Spectrometry ◽

Identification Of Bacteria ◽

Tof Ms

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently been demonstrated as a rapid and reliable method for identifying bacteria in colonies grown on culture plates. Rapid identification of food spoilage bacteria is important for ensuring the quality and safety of food. To shorten the time of analysis, several researchers have proposed the direct MALDI-TOF MS tequnics for identification of bacteria in clinical samples such as urine and positive blood cultures. In this study, processed soybean products (total 26 test samples) were initially conducted a culture enrichiment step and bacterial cells were separated from interfering components. Harvested bacterial cells were determined by MALDI-TOF MS and 16S rRNA gene sequencing method. Six processed soybean products (23%) were increased bacterial cells after culture enrichiment step and they were sucessfully obtained the accurate identification results by MALDI-TOF MS-based method without colony formation.

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MALDI-TOF MS-Based Analysis of Seed Proteins from Catalogue Varieties of Solanum lycopersicum/Lycopersicon esculentum

Horticulturae ◽

10.3390/horticulturae5030048 ◽

2019 ◽

Vol 5 (3) ◽

pp. 48

Author(s):

Michael Reeve

Keyword(s):

Lycopersicon Esculentum ◽

Sample Preparation ◽

Solanum Lycopersicum ◽

Seed Proteins ◽

Impatiens Glandulifera ◽

Invasive Weed ◽

Maldi Tof Ms ◽

Maldi Tof ◽

Commercial Plant ◽

Tof Ms

Matrix-assisted laser-desorption and ionization time-of-flight mass spectroscopy (MALDI-TOF MS) is a flexible technique for the analysis of protein-containing biological samples. Simple and inexpensive methods have previously been developed for MALDI-TOF MS sample preparation that are able to discriminate between Impatiens species that are closely related and also between regional biotypes of the invasive weed Impatiens glandulifera (Himalayan balsam) with leaf material and also seed material. The current article investigates whether MALDI-TOF MS, through acid-soluble protein ‘fingerprinting’, can be used to analyze plant seeds that result from intensive commercial plant-breeding activity. As an initial proof-of-concept study, tomato seeds from eleven seed-catalogue varieties (F1 Pink Baby Plum, F1 Fantasio, F1 Lizzano, F1 Sungold, F1 Tumbler, Faworyt, Golden Sunrise, Hundreds and Thousands, Indigo Rose, Moneymaker, and Red Alert), listed as Solanum lycopersicum or under the synonym Lycopersicon esculentum were analyzed using MALDI-TOF MS. Whilst peak-rich and highly-reproducible spectra were obtained, with very high Bruker comparison scores and low MALDI-TOF MS variance, sample-preparation variance, and seed-to-seed variance, the spectral differences between varieties were only slightly greater than the above combined variances, indicating very close similarity between all eleven varieties studied. These results are discussed in comparison with those previously observed with the naturally-evolving invasive species I. glandulifera.

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