Detection of the bacteriological sex factor in E. coli by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Abstract

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is employed to detect the presence of the bacteriological sex factor, a trait that allows some bacteria to transfer genetic information to others by means of conjugation. The principal advantage of the method is its speed. Twenty different strains of E. coli were analyzed and the results were consistent with previously known genetic information. The sex factor could be transferred from one strain to another and the outcome verified by mass spectrometry.

Mass Spectrometry and Integrated Virus Detection System Characterization of MS2 Bacteriophage

“…[16][17] More MS techniques have been used to characterize bacteria than viruses.' [8][9][10][11][12][13][14][15][16][17][18][19][20][21] This disparity is due to the significant difference in the number of protein biomarkers encoded in viruses compared to that of bacteria, and the thermal stability of the viral protein upon introduction into the ionization source of the MS (bacteria have a large number of proteins). 22 23 Bacteriophage MS2 is a Leviviridae virus specific to bacteria that contain the F plasmid.…”

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

“…This cross-correlation approach allowed strain identification from among 25 strains. Whole bacteria MALDI MS of various strains of E. coli was used to identify the presence or absence of sex factor proteins [120]. Although the complex consists of more than 30 proteins, only one indicative signal for the presence of the sex factor plasmid, m/z 9743, could be identified in the complicated lysate spectra, albeit that the structure of this protein remains unknown.…”

“…With the present state of knowledge, the influence of experimental conditions on ionisation efficiency in mixtures cannot be predicted to a sufficient extent as to allow conclusions regarding the presence or absence of specific proteins (biomarkers). Therefore, the use of marker signals for the distinction of genetically altered bacteria, demonstrated for example for E. coli [120], is not generally applicable. Some evidence has been presented that most E. coli biomarker signals, in whole cell MALDI MS up to 11,000 Da, do indeed result from proteins; a simple trypsin digest eliminated all biomarker signals from spectra [127].…”

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

“…Whole bacteria MALDI MS of various strains of E. coli was used to identify the presence or absence of sex factor proteins [128]. Although the complex consists of more than 30 proteins, only one indicative signal for the presence of the sex factor plasmid, m/z 9743, could be identified in the complicated lysate spectra, albeit that the structure of this protein remains unknown.…”

“…With the present state of knowledge, the influence of experimental conditions on ionisation efficiency in mixtures cannot be predicted to a sufficient extent as to allow conclusions regarding the presence or absence of specific proteins (biomarkers). Therefore, the use of marker signals for the distinction of genetically altered bacteria, demonstrated, e.g., for E. coli [128], is not generally applicable. Some evidence has been presented that most E. coli biomarker signals, in whole cell MALDI MS up to 11 000 Da, do indeed result from proteins; a simple trypsin digest eliminated all biomarker signals from spectra [137].…”