Identification of ancient biological samples from the 1991-discovered and more than 5300-year-old Tyrolean mummy, also called iceman or Oetzi, is very difficult. The species of origins of four animal-hair-bearing samples of the accoutrement of the mummy not yet diagnosed were identified by a special proteomics method. Ha 43/91/130 and Ha 6/91, two samples from his coat, and Ha 5/91, a sample from his leggings, were assigned to sheep. The upper leather of his moccasins, Ha 2/91, was made from cattle. Despite the enormous age of these samples with partial (bio)chemical alterations, reliable identification was possible using a recently developed matrix-assisted laser desorption/ionization time-of-flight mass spectrometric ((MALDI-TOF MS)-based analytical method. The method is exclusively based on the analysis of proteins and uses minute amounts of peptides directly derived from tryptic hair digests without any separation or enrichment steps. Unknown species are identified by comparison of their peptide ion patterns with known spectra stored in existing databases. Hereby, the correlation distance, a form of Euclidean distance, and deduced parameters are used to measure similarities. If more than one potential hit remains, specific diagnostic peptide ions are used to stepwise exclude incorrect matches. These ions are specific for orders, families, subfamilies/genera and/or even species. Peptide mass fingerprinting data combined with those from collision-induced dissociation spectra (combined MS & MS/MS) were used for interpretation with the MASCOT search engine and the NCBI database to find the potential parentage of hair proteins. For this technique, selected precursor ions were identified as specific diagnostic peptide ions.

The identification of fur origins from the 5300-year-old Tyrolean Iceman's accoutrement is not yet complete, although definite identification is essential for the socio-cultural context of his epoch. Neither have all potential samples been identified so far, nor there has a consensus been reached on the species identified using the classical methods. Archaeological hair often lacks analyzable hair scale patterns in microscopic analyses and polymer chain reaction (PCR)-based techniques are often inapplicable due to the lack of amplifiable ancient DNA. To overcome these drawbacks, a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method was used exclusively based on hair keratins. Thirteen fur specimens from his accoutrement were analyzed after tryptic digest of native hair. Peptide mass fingerprints (pmfs) from ancient samples and from reference species mostly occurring in the Alpine surroundings at his lifetime were compared to each other using multidimensional scaling and binary hierarchical cluster tree analysis. Both statistical methods highly reflect spectral similarities among pmfs as close zoological relationships. While multidimensional scaling was useful to discriminate specimens on the zoological order level, binary hierarchical cluster tree reached the family or subfamily level. Additionally, the presence and/or absence of order, family and/or species-specific diagnostic masses in their pmfs allowed the identification of mammals mostly down to single species level. Red deer was found in his shoe vamp, goat in the leggings, cattle in his shoe sole and at his quiver's closing flap as well as sheep and chamois in his coat. Canid species, like grey wolf, domestic dog or European red fox, were discovered in his leggings for the first time, but could not be differentiated to species level. This is widening the spectrum of processed fur-bearing species to at least one member of the Canidae family. His fur cap was allocated to a carnivore species, but differentiation between brown bear and a canid species could not be made with certainty.

We describe a fast method for the identification of the origin of native and chemically processed feathers, down, and hair and for distinguishing closely related species using enzyme digestion and MALDI-TOF mass spectrometry. Additionally we present two methods for the quantification of different identified bird and mammalian samples, respectively, in binary species mixtures. Without any prior cleaning or isolation of single proteins, enzymatical digests of feathers, down, and hair are performed. Fragments generated are analyzed by MALDI-TOF mass spectrometry, and peak groups of different selectivity are established for every animal species. For the identification of individual animal species, only unique species-specific peaks are accepted while for species classification of tinted or bleached hair, the group of semispecific peaks (SEMPs) is used. Samples from native animal species show a higher coincidence of digest peak masses of SEMPs than far-related species, indicating a phylogenetical relationship of the investigated structure proteins. Quantification of mixed binary avian samples is performed by identification of preweighed single feathers and down, followed by calculation of the gravimetric mass fractions. The composition of mixed binary mammalian samples is calculated from correlation of the quotient of the relative peak intensities or areas of these species and the quotient of corresponding gravimetric mass fractions. High accuracy is achieved by both quantification methods. The fast methods are well suited for industrial quality control for example.

No abstract

Abstract:The incidence and prevalence of onychomycosis are rising worldwide. Common diagnostic techniques often lack sensitivity or specificity. Differentiation between non-infectious nail disorders is frequently not possible. The aim of this study was to establish a better diagnostic routine procedure based on modern mass spectrometric peptide analysis techniques. One hundred and fifty-five nail samples from 145 patients with clinically suspected onychomycosis (n = 96, 62%) and without onychomycosis [e.g. nail psoriasis or nail dystrophy resulting from eczema (n = 59, 38%)] were investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peptide mass fingerprinting in comparison with standard techniques. We demonstrated that MALDI-TOF MS represents a precise, robust and fast tool in diagnostic investigation of nail disorders, which is superior to common standard methods.