Mass spectral investigations on microorganisms

Bacterial cells undergo lysis readily, when suspended in mild aqueous acids , and release the cellular proteins along with other biomolecules. Molecula r masses of the protein biomarkers released in-situ from individual intact bacterial cells could be directly measured by mass spectrometry. Limited sa mple clean up may be required at times, prior to mass spectral analysis, to remove any ionizable impurities such as salts, buffers and deergents. The marker proteins specific for individual genus, species and strains were det ermined by the comparison of the biomarkers measured for several closely re lated organisms. Even though there is a probability of over 4000 cellular p roteins expressed in any singlebacterial cell, only a small fraction of the projected marker proteins rue identified consistently during the process. This could be due to the variation in the ionization properties of the prot eins ansi the limited energy available to prompt their ionization. Variatio n in the sample processing and culture conditions had little effect in the marker proteins observed during the process. This experimental procedure en ables the distinction of gram positive as well as gram negative cellular pa thogens and their corresponding nonpathogenic counterparts. The identity of few bacterial cells present in unknown samples can be easily, rapidly and accurately established by adopting a procedure involving simple sample proc essing followed by direct mass spectral analysis and data prosessing. Thus, an uncomplicated approach has been developed to resolve a complex problem involving cellular pathogens. This method has enormous application potentia l in the rapid identification and subsequent prevention of any potential he alth hazard caused by the pathogenic bacteria, either under natural or indu ced conditions. There is a great potential for the total automation of the entire process in the future for simpler but more effective unattended oper ations in the laboratory as well as in the field.