Animal Species and Blood Identification with Peptide Mass Fingerprinting.

As more families are acquiring pets and the opportunities for wild animals to appear in human neighborhoods are increasing, the number of cases and accidents involving animals is increasing. Hence, the need to identify animal species from blood left over at accident sites is increasing. Human hemoglobin is used as a marker for human blood. Although tandem mass spectrometry is the dominant methodology used in proteomics research, peptide mass fingerprinting, given its instant applicability, may be useful for screening animal species, as the amino acid sequences of hemoglobin from various animals differ. In this study, solutions that were easily purified─using hemoglobin reagents from humans, Japanese macaques, bears, cattle, goats, sheep, sika deer, pigs, wild boars, dogs, cats, and nutrias─were digested by trypsin, and subjected to database searched using Mascot. No candidate proteins were found in the blood of goats, sheep, sika deer, wild boars, pigs, or nutrias. However, bloodstains from all animal species except nutria (which is not registered in the database) yielded candidates, which were identified as the hemoglobin of origin or its relatives. This difference may be attributed to more contaminants being included in blood. Further narrowing was possible using the average mass obtained via infusion electrospray ionization mass spectrometry measurement of the undigested solution in Mascot results. Saliva, urine, semen, and sweat collected from humans were also examined and searched for mascots, but no hits were obtained. In conclusion, this method may be useful for estimating animal species and identifying blood in forensic science.

Identification and evaluation of potential forensic marker proteins in vaginal fluid by liquid chromatography/mass spectrometry.

Vaginal fluid is one of the most common body fluids found at crime scenes. Discriminating vaginal fluid from other body fluids is important in forensic science; however, few potential protein markers have been reported to date. Proteomic methods for identifying protein markers have gained attention, although few reports have applied this technology to forensic protein markers. Therefore, to identify characteristic vaginal proteins, we examined various body fluids (nasal secretions, saliva, urine, semen, vaginal fluids, and sweat) using liquid chromatography/electrospray ionization time-of-flight mass spectrometry and peptide mass fingerprinting. We identified three components (average molecular mass values 17,237 ± 2, 18,063 ± 2, and 15,075 ± 1) detectable only in vaginal samples: two human small proline-rich protein 3 (SPRR3) isoforms and a human fatty acid-binding protein 5 (FABP5) with an acetylated (+42) N-terminal region lacking the initiator methionine residue (-131). Using ELISA, these yielded markedly high average values in vaginal fluids. The mass spectra of these proteins were not detected in infant saliva but were detected in the vaginal fluid throughout the menstrual cycle. The results of forensic analysis (detection limit, mixed body fluid samples, casework samples, and blind samples) suggest that these proteins are potential forensic markers. In conclusion, high SPRR3 and FABP5 expression levels, which may be used as potential markers for vaginal fluid identification in forensic science, were detected in vaginal fluids from healthy adults.

Detection of proline-rich proteins for the identification of saliva by enzyme-linked immunosorbent assay.

Saliva is one of the most common body fluids found at a crime scene. Therefore, identifying saliva is important in forensic science. However, the current protein marker assays used to identify saliva are not sufficiently specific. Although proline-rich proteins (PRPs) are highly specific for saliva, their forensic potential has not yet been investigated. In this study, we developed enzyme-linked immunosorbent assays (ELISAs) to detect acidic salivary PRP HaeIII subfamily 1/2 (PRH1/2) and basic salivary PRP 2 (PRB2). The specificity, sensitivity, and efficiency of the ELISAs for PRH1/2 and PRB2 were compared with those of the ELISA for statherin (STATH), a known protein marker for saliva. The levels of PRH1/2 were significantly higher in saliva and saliva stains than in other body fluids (nasal secretions, urine, semen, vaginal fluid, blood, and sweat). PRB2 and STATH were detected in both nasal secretions and saliva. The PRH1/2 ELISA showed sensitivity similar to that of STATH ELISA. The detection rate of PRH1/2 ELISA was almost similar to that of STATH ELISA, followed by the ELISA for PRB2. The PRH1/2 ELISA had higher specificity for saliva than STATH ELISA. Therefore, the PRH1/2 ELISA has potential as a method to identify saliva for forensic investigation.