We have updated the Biotyper library which now contains 6903 entries. More than 80 new yeast MSPs and more than 400 each Gram positive and Gram negative bacterial MSPs were included in this update.
The Facility’s PAGE equipment is free to use. If you don’t know how to run a gel, Tania can help!
Today, our doors are open to anyone who is interested in polymer analysis by MALDI-TOF MS.
Please stop by our Facility to learn more about our equipment and have a cup of coffee!
The Proteomics and Mass Spectrometry Core Facility is inviting everyone interested in polymer analysis by MALDI-TOF to an open house event on Friday, February 5th, 9 AM to 5 PM.
Come down the facility to see our instrumentation and discuss your next mass spectrometry analysis over some light refreshments!
Contact James Miller at firstname.lastname@example.org for more details.
The MALDI Biotyper identifies microorganisms by analyzing their intrinsic proteins using mass spectrometry.
An individual colony from an overnight culture grown on an agar plate is picked using a wooden toothpick and transferred to a MALDI target. This sample is allowed to dry, and a microliter of a matrix solution is added to the sample. The organic solvent in the matrix solution extracts proteins from the microorganisms. The extracted proteins are mainly ribosomal proteins, present in high concentrations. Once the matrix has crystallized, sample preparation is complete and the samples are ready for analysis. For some microorganisms, it is necessary to perform a more extensive extraction, which adds another 10-15 minutes to the sample preparation procedure.
In our facility, the analyses are carried out on the Bruker Ultraflextreme MALDI TOF/TOF mass spectrometer. Each MALDI mass spectrum is a species-specific molecular fingerprint, a mass and intensity distribution of peaks corresponding to mainly ribosomal proteins.
Identification of an unknown microorganism is based on comparing the experimental molecular fingerprint with 6903 fingerprints in the Biotyper library and assigning a score which represents the probability that the match is correct.
The algorithm used to compare patterns computes three separate values for three fundamental characteristics of the sample spectra and the reference spectra: the number of signals in the reference spectrum that have a closely matching partner in the unknown spectrum; the number of signals in the unknown spectrum that have a closely matching partner in the reference spectrum; and the intensity symmetry of the matching pairs. The maximum obtainable score is 3, and the score values greater or equal to 2 are considered as a probable identification.
Biotyper software allows building spectral libraries of any type of samples as long as the samples are amenable to MALDI-TOF MS and produce unique MS fingerprints. If you are interested in learning more about MALDI MS and the Biotyper, please contact Tatiana.
The acquisition of MALDI Biotyper software was possible through collaboration with Dr. Bhushan M. Jayarao, Director of Penn State Animal Diagnostic Laboratory, Professor of Veterinary and Biomedical Sciences.
Featured image credit: Rocky Mountain Laboratories, NIAID, NIH
Scanning electron micrograph of Escherichia coli, grown in culture and adhered to a coverslip
I am at the Upward Bound Math and Science research symposium, and the quality of students’ presentations is outstanding! Many of these kids are rising sophomores, i.e. have just finished 9th grade! So next time a postdoc or a Ph.D. candidate tells me “I don’t know how to cut out a gel band” or “I am not comfortable making a salt solution”, I will treat it as an attempt at making me feel freakishly smart.
Starting tomorrow, May 28th and through June 4th we will be hosting a mass spectrometry practicum as a part of the Penn State Bioinorganic Workshop. Orbi will be used by our colleagues from Northeastern University to demonstrate the power of high-resolution MS in the analysis of metalloenzymes. I will not be able to run samples on Orbitrap during the workshop.
The Mass Spec Facility must regretfully announce that the open access liquid chromatograph/mass spectrometer is no longer operational. The instrument, an AB Sciex 150EX single quad mass spectrometer, was purchased in 2006, and has been nearing the end of its life span. The instrument is no longer supported by the manufacturer, so parts and qualified service will be increasingly hard to find. Thus, it is not possible for the facility to maintain.
Nominal mass samples can still be submitted to the facility and will be given high priority for quick turnaround (generally 24 hrs. or less). Prior to the purchase of the 150EX the facility routinely ran nominal mass samples in this manner. Contact James Miller (email@example.com) with any questions you might have.