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Biochemical markers for the detection and classification of Aspergillus

Glassbrook, Norman J. 2008. Biochemical markers for the detection and classification of Aspergillus. PhD Thesis, Cardiff University.

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Abstract

The genus Aspergillus includes a diverse group of filamentous fungi that are widely distributed in nature, commonly found in soil. The Aspergilli include species that can be beneficial or detrimental to humans, so detection and accurate identification of these organisms can be very important. Morphology and genetic sequence analysis are well established methods for classifying and identifying fungi, but morphology remains a widely used technique that generally works well for Aspergilli. However, some organisms may be misidentified due to atypical morphology and some hidden (cryptic) species may not be recognized as different from named species based on readily observable traits. In this study, reference strains of different Aspergillus species, <italic>Penicillium chrysogenum, Candida albicans,</italic> and <italic>Cryptococcus neoformans </italic> were characterized using LC/MS and GC/MS biochemical profiling techniques in order to find specific small molecules, peptides or biochemical profiles that can be used in addition to established methods to detect and classify Aspergilli to the species level. Subsequently, analytical methods developed for characterizing the reference strains were applied, along with morphology and PCR, to characterize and identify several laboratory and field isolates. Some unique compounds and biochemical patterns did emerge from small molecule profiling that could be used for classifying Aspergilli, but protein profiling by LC/MS/MS was a much more effective approach. Tandem mass spectra from LC/MS/MS of tryptic peptides from fungal proteins were searched against protein databases and matched to theoretical spectra derived from those databases. Many of the amino acid sequences detected were taxonomically diagnostic for classifying Aspergillus species. Protein profiling also provided a great deal of additional biochemical information on the test organisms by identifying the predominant enzymes and structural proteins present under different experimental conditions and may find broader application for identifying and studying other organisms.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Biosciences
Subjects: Q Science > QR Microbiology
ISBN: 9781303214158
Date of First Compliant Deposit: 30 March 2016
Last Modified: 19 Mar 2016 23:31
URI: http://orca-mwe.cf.ac.uk/id/eprint/54802

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