Related Experiment Video

Updated: Aug 21, 2026

Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS
06:34

Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS

Published on: July 11, 2016

Enhanced specificity of bacterial spore identification by oxidation and mass spectrometry

Plamen A Demirev1

  • 1Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723, USA. plamen.demirev@jhuapl.edu

Rapid Communications in Mass Spectrometry : RCM
|October 19, 2004
PubMed

Insights

Oxidizing Bacillus spores with hydrogen peroxide modifies methionine-containing proteins. This mass shift in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) confirms biomarker identity and aids rapid spore identification.

Area of Science:

  • Microbiology
  • Analytical Chemistry
  • Biochemistry

Background:

  • Bacillus spores are identified using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS).
  • Accurate identification relies on precise protein mass determination.
  • Methionine (Met) residues in proteins can complicate mass spectrometry analysis.

Purpose of the Study:

  • To develop a rapid method for confirming Bacillus spore identification using MALDI-MS.
  • To leverage protein oxidation for enhanced biomarker analysis.
  • To validate spore identification by accurately determining methionine residue counts.

Main Methods:

  • Intact Bacillus spores were treated with an oxidizing agent (hydrogen peroxide).
  • Oxidation selectively converted methionine residues to methionine sulfoxides.
  • Mass shifts in proteins were analyzed using MALDI-MS to determine the number of methionine residues (n).

Main Results:

  • The oxidation procedure rapidly and completely modified Met-containing biomarker proteins.
  • Observed mass increases (Deltam = 16 x n Da) directly correlated with the number of Met residues.
  • Experimentally determined mass shifts accurately confirmed predicted methionine counts.

Conclusions:

  • This in situ oxidation method provides a reliable way to confirm biomarker identity in Bacillus spores.
  • Accurate determination of methionine residue numbers via mass spectrometry validates spore identification.
  • The technique offers a rapid and efficient approach for microbial identification.

More Related Videos

Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics (MSPP)09:43

Subtyping of Campylobacter jejuni ssp. doylei Isolates Using Mass Spectrometry-based PhyloProteomics (MSPP)

Published on: October 30, 2016

Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment (Kartchner Caverns, AZ, USA)11:09

Use of MALDI-TOF Mass Spectrometry and a Custom Database to Characterize Bacteria Indigenous to a Unique Cave Environment (Kartchner Caverns, AZ, USA)

Published on: January 2, 2015

Related Concept Videos

Rapid Identification of Pathogens01:25

Rapid Identification of Pathogens

MALDI-TOF MS has transformed clinical microbiology by offering a rapid and reliable method for pathogen identification. The traditional approach to microbial identification typically involves time-consuming culture techniques and biochemical tests, which can delay the initiation of appropriate antimicrobial therapy. MALDI-TOF MS avoids these delays by using characteristic ribosomal protein mass patterns of microbial cells, enabling accurate species-level identification within minutes.Principle...
Special Staining Techniques01:13

Special Staining Techniques

Specialized staining techniques play a vital role in microbiology by enabling the visualization of specific bacterial structures that remain undetectable with standard microscopy methods. These techniques not only enhance the structural visualization of bacterial cells but also provide critical insights into their pathogenicity and classification. Additionally, they support diagnostic and research endeavors in microbiology by identifying key bacterial features.Capsule Staining for Virulence...
MALDI-TOF Mass Spectrometry01:19

MALDI-TOF Mass Spectrometry

Mass spectrometry is a powerful characterization technique that can identify and separate a wide variety of compounds ranging from chemical to biological entities, based on their mass-to-charge ratio (m/z). The instruments that allow this detection, known as mass spectrometers, have three components: an ion source, a mass analyzer, and a detector. These spectrometers differ based on the nature of their ion source and analyzers.Matrix-assisted laser desorption ionization (MALDI) is a commonly...
Mass Spectrometry: Isotope Effect01:13

Mass Spectrometry: Isotope Effect

Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the mass differences between isotopes. Furthermore, the intensity of these signals is dependent on the...
Mass Spectrometry: Overview01:19

Mass Spectrometry: Overview

Mass spectrometry is an analytical technique used to determine the molecular mass and molecular formula of a compound. The basic principle of mass spectrometry is to generate ions from the analyte molecule and measure these ion abundances against their molecular mass. One common type of ionization, known as electron ionization or EI, bombards the analyte molecules in the gas phase with high-energy electron beams. The electron beams displace an electron from the molecule and leave behind a...
Methods of Classification and Identification01:28

Methods of Classification and Identification

Bacterial identification relies on a diverse array of techniques to classify and understand microorganisms, each tailored to uncover specific characteristics. Traditional morphological approaches, while still valuable, are limited for closely related or structurally simple organisms. Modern methods integrate biochemical, serological, genetic, and advanced molecular tools to achieve greater accuracy.Morphological and Biochemical TechniquesMorphological characteristics, such as cell shape and...