Keratin Samples Research Articles

Stable isotope analyses of carbon and nitrogen in hair keratin of suspected man-eating wolves from 1880s

The so-called man-eating wolves of Turku, a pack of three wolves, reportedly killed 22 children in South-Western Finland in 1880–1881. Enormous efforts were carried out to eradicate them. In January 1882 the last remaining wolf was killed. Since then, there has been considerable debate regarding the validity and extent of the man-eating behaviour. This study aims to clarify whether man-eating behaviour can be observed from the remains of these wolves. One of the wolves was mounted in 1882 and is on display at St. Olaf’s school in Turku, enabling us to collect hair keratin samples. Additionally, hair keratin was collected from two other suspected man-eaters. We analysed carbon (δ13C) and nitrogen (δ15N) stable isotope values to study the wolf’s diet during the last months of its life. Samples from seven temporally concurrent wolves were used to construct reference values. Our analyses indicated that δ15N values of suspected man-eaters were relatively low compared to the reference sample. We could not detect clear trends in isotope ratios associated with potential man-eating behavior. We believe that this lack of distinctive patterns can be explained by the relatively minor role that man-eating played in their overall diet.

Various Drying Techniques for Conversion of Extracted Chicken Feather Keratin Solution to Powder

Keratin powder is produced from the drying of keratin solution extracted from chicken feathers. Powdered form of keratin protein eases the storage and transport of keratin and can be further developed into nutrient supplements. The objective of this research is to convert liquid keratin obtained from chicken feathers into powder through different methods and also to identify the effects of various drying methods on the keratin sample. Liquid keratin was converted into solid particles through spray drying, freeze drying and vacuum-oven drying where the products were visually observed and analysed using FTIR and SEM to determine the effects of the drying methods on the keratin sample. The SEM results show that the product of spray drying produced smaller spherical particles with diameter ~3µm-17µm while freeze drying and vacuum-oven drying produced coarse, flaky irregular-shaped particles with diameter ~70µm-470µm and ~100µm-530µm respectively. FTIR spectroscopy shows that the keratin samples remained their characteristics as a true protein including spray drying when encapsulated with Arabic gum even at high temperatures up to 110°C. Conclusively, spray drying should be considered for future development of keratin as a nutrient supplement while freeze drying and vacuum-oven drying for storage and transport of keratin.

Water uptake by gecko β-keratin and the influence of relative humidity on its mechanical and volumetric properties.

Grand canonical ensemble molecular dynamics simulations are done to calculate the water content of gecko β-keratin as a function of relative humidity (RH). For comparison, we experimentally measured the water uptake of scales of the skin of cobra Naja nigricollis. The calculated sigmoidal sorption isotherm is in good agreement with experiment. To examine the softening effect of water on gecko keratin, we have calculated the mechanical properties of dry and wet keratin samples, and we have established relations between the mechanical properties and the RH. We found that a higher RH causes a decrease in the Young's modulus, the yield stress, the yield strain, the stress at failure and an increase in the strain at failure of the gecko keratin. At low RHs (less than 80%), the change in the mechanical properties is small, with most of the changes occurring at higher RHs. The changes in the macroscopic properties of the keratin are explained by the action of sorbed water on the molecular scale. It causes keratin to swell, thereby increasing the distances between amino acids. This has a weakening effect on amino acid interactions and softens the keratin material. The effect is more pronounced at higher RHs.

From Strain Stiffening to Softening-Rheological Characterization of Keratins 8 and 18 Networks Crosslinked via Electron Irradiation.

Networks of crosslinked keratin filaments are abundant in epithelial cells and tissues, providing resilience against mechanical forces and ensuring cellular integrity. Although studies of in vitro models of reconstituted keratin networks have revealed important mechanical aspects, the mechanical properties of crosslinked keratin structures remain poorly understood. Here, we exploited the power of electron beam irradiation (EBI) to crosslink in vitro networks of soft epithelial keratins 8 and 18 (k8–k18) filaments with different irradiation doses (30 kGy, 50 kGy, 80 kGy, 100 kGy, and 150 kGy). We combined bulk shear rheology with confocal microscopy to investigate the impact of crosslinking on the mechanical and structural properties of the resultant keratin gels. We found that irradiated keratin gels display higher linear elastic modulus than the unirradiated, entangled networks at all doses tested. However, at the high doses (80 kGy, 100 kGy, and 150 kGy), we observed a remarkable drop in the elastic modulus compared to 50 kGy. Intriguingly, the irradiation drastically changed the behavior for large, nonlinear deformations. While untreated keratin networks displayed a strong strain stiffening, increasing irradiation doses shifted the system to a strain softening behavior. In agreement with the rheological behavior in the linear regime, the confocal microscopy images revealed fully isotropic networks with high percolation in 30 kGy and 50 kGy-treated keratin samples, while irradiation with 100 kGy induced the formation of thick bundles and clusters. Our results demonstrate the impact of permanent crosslinking on k8–k18 mechanics and provide new insights into the potential contribution of intracellular covalent crosslinking to the loss of mechanical resilience in some human keratin diseases. These insights will also provide inspiration for the synthesis of new keratin-based biomaterials.

Pharmacokinetics of Nebulized Terbinafine in Plasma and Keratin of Northwestern Pond Turtles (Actinemys marmorata) Associated with Emydomycosis

The Northwestern pond turtle ( Actinemys marmorata ) is native to Washington State, USA and has developed a grossly evident form of shell disease affecting a large percentage of the free-ranging population in this state. Emydomyces testavorans is a novel fungus in the order Onygenales that is the presumed causative agent for shell disease in the Northwestern pond turtle. Terbinafine hydrochloride is a lipophilic allylamine broad spectrum antifungal that penetrates keratin and concentrates in the stratum corneum. This study evaluated the drug concentration in the plasma and keratin of 18 Northwestern pond turtles after nebulization with 18 mg terbinafine solution (2 mg/ml) once a day for 28 days. Blood and keratin samples were collected serially during the course of treatment, and for 14 days following the last dose. Plasma and keratin were analyzed by high-performance liquid chromatography. No significant concentrations of terbinafine were found in the plasma of the turtles. Terbinafine in turtle keratin peaked after 16 days of treatment and maintained therapeutic concentrations for 14 days post treatment. Turtle shell lesions also showed signs of clinical improvement post-therapy. Nebulization of terbinafine is recommended for the treatment of shell disease secondary to Emydomyces testavorans , however pulse antifungal therapy is likely needed to prevent disease from reoccurring.

A global carbon and nitrogen isotope perspective on modern and ancient human diet

Stable carbon and nitrogen isotope analyses are widely used to infer diet and mobility in ancient and modern human populations, potentially providing a means to situate humans in global food webs. We collated 13,666 globally distributed analyses of ancient and modern human collagen and keratin samples. We converted all data to a common "Modern Diet Equivalent" reference frame to enable direct comparison among modern human diets, human diets prior to the advent of industrial agriculture, and the natural environment. This approach reveals a broad diet prior to industrialized agriculture and continued in modern subsistence populations, consistent with the human ability to consume opportunistically as extreme omnivores within complex natural food webs and across multiple trophic levels in every terrestrial and many marine ecosystems on the planet. In stark contrast, isotope dietary breadth across modern nonsubsistence populations has compressed by two-thirds as a result of the rise of industrialized agriculture and animal husbandry practices and the globalization of food distribution networks.

Extraction and Characterization of Keratin from Chicken and Swiftlet Feather

Keratin is a durable and fibrous protein of hair, nails, horns, hoofs, feathers and the epithelial cells in the outermost layers of the skin. Keratin in animals mainly presents in vertebrates such as mammals, birds and reptiles including chicken and swiftlet. This study aims to characterize keratin extracted from chicken and swiftlet feathers. The extraction of the keratin performed using dimethyl sufoxide (DMSO) at high temperature. The extracted keratin from both samples were used for the characterization process using Bradford protein assay, CHNS analysis and Fourier-transform infrared (FTIR) spectroscopy. This study showed that keratin extract of swiftlet feather showed higher protein concentration (0.813 mg/mL) than keratin extract of chicken feather (0.646 mg/ml). The highest composition for keratin extract is hydrogen which are 4.97% for keratin extract from swiftlet feathers and 3.12% for keratin extract from chicken feathers. FTIR analysis exhibited that carboxyl groups and amino groups are presence in both keratin samples however, the protein value is higher in swiftlet feathers compared to chicken feathers. This study's outcome is significant in discovering keratin extract from swiftlet feathers containing high protein content due to the breakdown of disulfide bonds. Furthermore, this research is the first report on keratin characterization from swiftlet feathers that would be useful for high value future keratin study.

Comparative analysis of the chemical treatments used in keratin extraction from red sheep’s hair and the cell viability evaluations of this keratin for tissue engineering applications

Hair waste is one of the solid substances rejected by the leather industry. This waste finds its way into the surroundings causing serious environmental pollution. This hair waste may be utilized for effective extraction of keratin, thereby generating value-added products with numerous applications. Thus we focusing on utilizing red sheep’s hair waste for extracting keratin by the application of different chemical treatments such as sodium hydroxide, sodium sulfide, mercaptoethanol, cysteine, sodium metabisulfite with urea (SMB), and SMB with SDS (SMBS). CD spectrum and FTIR results of the keratin samples indicated a predominance of the helical conformation along with β sheets. SDS-PAGE confirmed the molecular weight of the keratin samples to be in the range of 40–60 kDa. DSC and TGA analysis exhibited the extracted keratin to have a higher denaturation temperature (>200 °C) and thermal stability. The keratin samples obtained using varied chemical treatments were compared in terms of yield, protein content, and cost-effectiveness, and the sample obtained using SMBS was preferred for in vitro studies. It is indicated that keratin extracted using SMBS effectively involved for fibroblast cell growth. Thus, we suggest that these keratin could produce biomaterials that can serve as a valuable material for biomedical applications.

Stable carbon isotope diagnostics of mammalian metabolism, a high-resolution isotomics approach using amino acid carboxyl groups.

The carbon isotopic compositions of amino acids are increasingly measured to characterize diets and metabolic response to diets. We report a new high-resolution system to measure the stable carbon isotopic composition of carboxyl atoms within amino acids. The automated system used HPLC to separate amino acids followed by addition of ninhydrin for decarboxylation and transfer of the evolved CO2 to a stable isotope ratio mass spectrometer for δ13CCARBOXYL measurement. The ninhydrin reaction was conducted at acidic pH (1.5) and elevated temperature (160 oC) giving yields close to 100% for most common amino acids. Eight mammalian keratin samples from herbivores (kudu and caribou), omnivores (humans) and carnivores (bowhead and humpback zooplanktivorous whales) were analysed with this new system. The data provide an initial calibration of reference materials to be used in studies of this type and is the first report of carboxyl carbon isotope distributions in mammals. Results showed widespread 13C enrichments in both essential and non-essential amino acid carboxyl groups, likely linked to decarboxylation of amino acids during normal metabolism. Analyses of non-essential amino acid isotope profiles showed (1) consistent and general taxon-level metabolic differences between the herbivore, human and whale samples, (2) marked differences among individual humans, ruminants and whales (3) evidence for gluconeogenesis in the wildlife samples, and (4) extensive 13C enrichment likely associated with fasting in the humpback whale sample. Future mammalian research related to the metabolism of growth, reproduction, aging and disease may benefit from using this technique. Values obtained for internationally available samples USGS42 and USGS43 (Tibetan and Indian human hair) provide a first characterization of reference materials for δ13CCARBOXYL profiles.

Thermal property study of keratin from industrial residue by extraction, processing and application

The Brazilian productive chain of poultry meat is one of the most important of the agro-industrial complex in the country. However, this production generates large amounts of residue, causing environmental impacts. After its processing, poultry industry waste can be considered a great potential by-product and a sustainable alternative for animal food and to applications in the cosmetics industry. It can be estimated that the number of produced feathers in Brazil reaches up to around 670 thousand tons annually. This study aimed to obtain keratin from chicken feathers and their characterization by thermal analysis, as well as adding the product into shampoo formulation as well its application on hair samples and compare it to commercial shampoo. Thermal analytical study was performed for all samples by TG/DTG, DTA and DSC. Rheology and FTIR analyses of extracted keratin samples and commercial keratin solution were also performed. Results showed that the extraction process used was efficient, once the TG curves of the samples presented one decomposition stage referring to proteins and DSC curves showed endothermic events suggesting protein denaturation. The shampoo formulations with keratin applied to hair samples showed satisfactory results, such as increased brightness, smoothness and reduced frizz.

Hoof Growth Rates of the European Roe Deer (Capreolus capreolus) for Dating the Hoof’s Isotopic Archive

Hooves preserve the isotopic information laid down during their growth and may be used for reconstruction of animal feeding history. To assign certain positions along hooves to corresponding times, growth rates are required. Hoof growth rates are known for domestic animals; however, they cannot be obtained easily in wild animals. We estimated the hoof growth rate of the European roe deer (Capreolus capreolus L.) by using the immediate drop in δ13C along the hoof as a tag that is assigned to the date of maize (Zea mays L.) harvest. Keratin samples were taken each mm along 17 hooves and analyzed for their δ13C. A linear regression between (1) time differences of expected maize harvest to animal death and (2) distances between the points of the δ13C drop to the periople yielded the growth rate. Mean hoof growth rate was 0.122 mm/day (95% CI 0.014 mm/day) and 0.365%/day (±0.026%/day) of the hoof length and within the range of domestic animals. The method may be applied to determine growth rates of other incrementally growing tissues. Our estimated growth rate fosters dating isotopic information in hooves, facilitating research on feed resources and space use of roe deer.

Stable isotopes uncover trophic ecology of the West African crocodile (Crocodylus suchus)

Stable isotope analysis is a widespread tool in ecological studies of diet composition and habitat use. In deserts, freshwater environments constitute threatened local hotspots of biodiversity. In these environments, stable isotopes may help to describe trophic ecology of top-predators. We examined stable carbon (δ13C) and nitrogen (δ15N) isotopes from scute keratin samples of 33 Crocodylus suchus and muscle samples from 39 potential prey collected in Southern Mauritania. Isotope ratios were compared among crocodiles according to size (non-adult and adult), and habitat (rock pools and floodplains). There was a significant interaction effect of habitat and size on crocodile δ13C values. Whereas δ13C was similar for all crocodiles collected in rock pools, adults had lower signatures than non-adults in seasonal floodplains. δ15N indicated an ontogenetic dietary shift with adult crocodiles foraging on prey from higher trophic level. Standard ellipse areas showed wider isotopic niches for adult than non-adult crocodiles, and within adults, for those from floodplains than those from rock pools. These environments are small, seasonal, overexploited for livestock watering, and polluted. They support very small and isolated crocodile populations. This study is aimed to provide conservation authorities with baseline information to strictly protect water-bodies where these predators subsist in arid environments.

An improved method for solubilisation of wool keratin using peracetic acid

Keratin in wool is a potentially important natural source of protein with many applications. However, solubilisation of keratin from wool is challenging. The yield of solubilised keratin was investigated using peracetic acid (PA) treatment of wool. The yield of keratin obtained by extraction of wool with various concentrations of PA (6, 12, 24 and 36%) with 1, 2, or 3days of treatment time was examined. Treatment of wool for two days with 24% PA was found to be the optimum treatment condition, resulting in a 57% yield of water soluble keratin (WSK) and a 40% yield of insoluble keratin (ISK). The physicochemical properties of the obtained keratin samples were determined using XRD, FTIR and SDS-PAGE. FTIR analysis of the WSK and ISK showed both extracts had a high content of cysteine-S-sulfonated residues and SDS-PAGE confirmed that the extracts contained proteins in the 40–60kDa molecular weight range.

Biomarkers reveal sea turtles remained in oiled areas following the Deepwater Horizon oil spill.

Assessments of large-scale disasters, such as the Deepwater Horizon oil spill, are problematic because while measurements of post-disturbance conditions are common, measurements of pre-disturbance baselines are only rarely available. Without adequate observations of pre-disaster organismal and environmental conditions, it is impossible to assess the impact of such catastrophes on animal populations and ecological communities. Here, we use long-term biological tissue records to provide pre-disaster data for a vulnerable marine organism. Keratin samples from the carapace of loggerhead sea turtles record the foraging history for up to 18years, allowing us to evaluate the effect of the oil spill on sea turtle foraging patterns. Samples were collected from 76 satellite-tracked adult loggerheads in 2011 and 2012, approximately one to two years after the spill. Of the 10 individuals that foraged in areas exposed to surface oil, none demonstrated significant changes in foraging patterns post spill. The observed long-term fidelity to foraging sites indicates that loggerheads in the northern Gulf of Mexico likely remained in established foraging sites, regardless of the introduction of oil and chemical dispersants. More research is needed to address potential long-term health consequences to turtles in this region. Mobile marine organisms present challenges for researchers to monitor effects of environmental disasters, both spatially and temporally. We demonstrate that biological tissues can reveal long-term histories of animal behavior and provide critical pre-disaster baselines following an anthropogenic disturbance or natural disaster.

Surface active complexes formed between keratin polypeptides and ionic surfactants

Keratins are a group of important proteins in skin and hair and as biomaterials they can provide desirable properties such as strength, biocompatibility, and moisture regaining and retaining. The aim of this work is to develop water-soluble keratin polypeptides from sheep wool and then explore how their surface adsorption behaves with and without surfactants. Successful preparation of keratin samples was demonstrated by identification of the key components from gel electrophoresis and the reproducible production of gram scale samples with and without SDS (sodium dodecylsulphate) during wool fibre dissolution. SDS micelles could reduce the formation of disulphide bonds between keratins during extraction, reducing inter-molecular crosslinking and improving keratin polypeptide solubility. However, Zeta potential measurements of the two polypeptide batches demonstrated almost identical pH dependent surface charge distributions with isoelectric points around pH 3.5, showing complete removal of SDS during purification by dialysis. In spite of different solubility from the two batches of keratin samples prepared, very similar adsorption and aggregation behavior was revealed from surface tension measurements and dynamic light scattering. Mixing of keratin polypeptides with SDS and C12TAB (dodecyltrimethylammonium bromide) led to the formation of keratin-surfactant complexes that were substantially more effective at reducing surface tension than the polypeptides alone, showing great promise in the delivery of keratin polypeptides via the surface active complexes. Neutron reflection measurements revealed the coexistence of surfactant and keratin polypeptides at the interface, thus providing the structural support to the observed surface tension changes associated with the formation of the surface active complexes.

Thermoanalytical characterization study of hair from different ethnicities

A characterization study of the samples of hair and animal keratin was performed to enhance the understanding of the thermal properties of the hair of the main ethnic groups. The mechanical, physicochemical and thermal properties of Caucasian, Oriental and African-ethnic hair have been widely described; however, this research adds knowledge about the thermal and analytical properties of these types of hair. To achieve such objective, thermogravimetry (TG), differential scanning calorimetry (DSC) and elemental analysis techniques were employed. To estimate the thermal stability of the hair samples, TG carried out a non-isothermal TG method kinetic study. The results obtained of TG/DTG showed similarity between the samples of hair and animal keratin, for all the events of thermal decomposition involved with mass loss. African-ethnic hair sample presented the lower thermal stability. This fact can be related to the data literature that showed that this type of ethnicity has the less tensile strength and breaks more easily than others types of the hair. Oriental hair sample showed to be, from the non-isothermal TG method kinetic study, more thermally stable than the other samples. DSC results showed that the hair samples presented melting/denaturation of the crystalline phase; however, animal keratin sample did not present such.

Paleodiet in the Paracas Necropolis of Wari Kayan: carbon and nitrogen isotope analysis of keratin samples from the south coast of Peru

Despite being one of the most famous archaeological cemeteries in Peru, many questions remain about the people who were buried at the Paracas Necropolis of Wari Kayan, which was first excavated by Julio C. Tello in 1925. Here, we use bioarchaeology and biogeochemistry to elucidate the lives of individuals buried at Wari Kayan. More specifically, we present 90 new δ13Ckeratin and δ15Nkeratin values from 14 individuals buried at Wari Kayan and two artifacts made of human hair (mean δ13Ckeratin (VPDB) = −15.3 ± 0.9‰ (1σ, n = 90) and mean δ15Nkeratin (AIR) = +15.5 ± 1.2‰ (1σ, n = 90)). We interpret these light stable isotope data from archaeological human hair samples from the Paracas Necropolis of Wari Kayan as evidence for a mixed diet of C4 and C3 foods as dietary carbon sources and marine products as dietary nitrogen sources. Sequential hair samples from the same individuals do not exhibit large isotopic differences in hair that formed at different times before death. In addition to elucidating paleodiet at this important site, we interpret sequential isotopic hair data as evidence of a population whose diet was predominately coastal in the last weeks or months of life, either remaining on the coast or consuming coastal products in the highlands. These data elucidate paleodiet as well as the utility of applying newer isotopic methods to archaeological human remains from older museum collections to gain a better understanding of the past.

An assessment of procedures to remove exogenous Sr before 87Sr/86Sr analysis of wet archaeological wool textiles

Strontium isotope analysis (87Sr/86Sr) has been employed as a provenancing tool for archaeological wool textiles. To date, the effect of post-depositional (soil burial environment) contamination on keratin samples, which contain ∼ppm concentrations of Sr, has not been rigorously investigated. We compared published methods for removing exogenous Sr from keratinous textiles, using either: (1) compressed N2 gas, (2) HF(aq) solution (with and without a strong oxidising agent to remove dyestuff) or (3) organic solvents. 87Sr/86Sr ratios and Sr contents were determined in undyed and madder-dyed/alum-mordanted moieties of the same wool textile, buried for up to three years in contrasting environments (marine sediment/fenland bog), and two archaeological textiles recovered in Iceland (one typical and one atypical of local manufacture). Undyed experimental samples had low Sr contents (0.07–0.29 ppm) that were increased by both dyeing (0.14–8.92 ppm) and soil burial (0.11–15.01 ppm). The efficacy of Sr removal was: HF(aq) + oxidising agent > organic solvents > HF(aq) > compressed N2. Unburied samples showed little variation in 87Sr/86Sr ratio between cleaning methods (0.00006–0.00035); buried samples showed greater variation (0.00257–0.00713). Archaeological samples showed Sr contents greater than experimental soil burials (1–118 ppm), and 87Sr/86Sr values consistent with Icelandic groundwater (0.70357–0.70540). No cleaning methods retrieved original (unburied and undyed) 87Sr/86Sr ratios except treatment with compressed N2 in undyed samples. Exogenous Sr from the short term soil burial environment is probably mostly present as particulates. We conclude that 87Sr/86Sr ratios of archaeological wool textiles recovered from wet burial environments do not accurately reflect wool provenance even after cleaning with the methods investigated.

Mycological study on cholesteatoma keratin obtained during primary mastoid surgery.

Established middle-ear cleft cholesteatoma is associated with keratinous debris, which is likely to be an ideal medium for saprophytic fungal colonisation. This prospective case study aimed to explore the incidence and nature of fungal elements in cholesteatoma keratin samples obtained during primary mastoid surgery. All cases of middle-ear cleft cholesteatoma treated with primary mastoid surgery at the El-Sahel Teaching Hospital over a seven-month period were included. Keratinous debris obtained from the mastoid antrum was subjected to mycological analysis at the Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University. A literature search was performed to determine the clinical and pathological relevance of fungal colonisation in cholesteatoma. Eighteen patients underwent primary mastoid surgery for cholesteatoma (nineteen ears in total) in a seven-month period starting 30 March 2013. Patients included 13 males and 5 females, with an age range of 9 to 45 years (mean 23 years). Fungal cultures were obtained from 17 keratin samples (89 per cent). Of these, five fungal isolates belonged to the dermatophyte group (21 per cent). Fungal colonisation in middle-ear cleft cholesteatoma probably plays a significant role in disease progression. Moreover, saprophytic fungal colonisation in cholesteatoma keratin may be responsible for the fetor commonly associated with the ear discharge.

Wet degradation of keratin proteins: linking amino acid, elemental and isotopic composition.

Archaeological keratin samples are increasingly the subject of palaeodietary, provenancing and dating studies. Keratin samples from wet archaeological contexts are microbiologically and chemically degraded, causing differential diagenesis of protein structures in hair fibres. The effects of these processes on the analytical parameters of interest are currently unknown. This study examined the impact of degradation of wool fibres on isotopic (δ(13)C, δ(15)N, un-exchangeable δ(2)H and δ(18)O values) composition. It compared two models of archaeological protein degradation in wet burial environments: (1) short term (up to 8 years) experimental burial in three contrasting soil environments; and (2) laboratory wet conditions, in which elevated temperature (80 °C, 110 °C, and 140 °C) and pressure simulated longer exposure. Elemental and amino acid (AA) composition were also measured. In experimentally soil-buried samples, AA, elemental and isotopic composition changes were small, despite extensive macroscopic alteration. Isothermally heated samples showed preferential loss of hydrophilic AAs (Asx, Glx, Ser, Gly) from wool residues, with depletion in (2)H and (18)O at higher temperatures (up to -73‰ change in δ(2)H and -2.6‰ in δ(18)O values). The δ(13)C and δ(15)N values showed little change except in densely pigmented samples at low temperatures only. Samples dyed with madder/alum were better preserved than undyed samples. Diagenesis in experimentally soil-buried wool textiles was consistent with microbiological, non-protein-selective activity, in contrast to highly AA-selective hydrolytic behaviour under laboratory wet conditions. Changes in δ(2)H and δ(18)O values were correlated with degree of AA change, but the δ(13)C and δ(15)N values were not. The results contribute to a baseline for interpreting analytical data from archaeological hair samples preserved by burial in wet environments.