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PubMed1996

Cell-bound and extracellular matrix-associated alkaline phosphatase activity in rat periodontal ligament. Experimental Oral Biology Group.

In previous studies it was noted that alkaline phosphatase (ALP) activity in periodontal ligament does not only seem to be related to cells but may also be associated with the extracellular matrix. In an attempt to clarify this we studied the distribution of the enzyme at the electron microscopic level. In addition, ALP-activity was assessed biochemically following extraction of the ligament with (i) agents dissolving the membrane or splitting the phosphatidylinositol anchor (Triton X-100 or phosphatidylinositol-phospholipase C, respectively), and (ii) a matrix-degrading enzyme cocktail (collagenase, hyaluronidase and elastase). Histochemical observations revealed (a) a heterogeneous distribution of ALP-activity, with highest activity adjacent to the alveolar bone and (b) two pools of activity; one bound to cells and one associated with the collagenous extracellular matrix. In line with this were the biochemical data indicating that approximately 10% of the enzyme activity was firmly bound to the extracellular matrix and 90% to plasma membranes. Isoelectric focusing did not reveal differences between the two fractions, both samples yielding a single broad band corresponding with an isoelectric point of about 4.4.

Alkaline Phosphatase↗
PubMed1985

Intersubunit disulfides of the follitropin receptor.

The electrophoretic mobility of radioiodinated follitropin (FSH) alpha and beta subunits as well as the alpha beta dimer changed markedly depending on the concentration of reducing agents such as dithiothreitol. The changes were more dramatic in the beta subunit than in the alpha subunit. 125I-FSH, complexed to the receptor on porcine granulosa cells or in Triton X-100 extracts, was cross-linked with a cleavable (nondisulfide) homobifunctional reagent, solubilized in sodium dodecyl sulfate without reducing agents, and electrophoresed. The cross-linked sample revealed three bands of high molecular mass, in addition to the hormone subunit and dimer bands. The band of lightest mass, 110 kDa, was the major band and the other two of 76 and 62 kDa were barely noticeable. Upon reduction with dithiothreitol, the 110-kDa band decreased while the 76- and 62-kDa bands increased, indicating the existence of disulfides between components of the 110-kDa complex. Formation of the disulfide-linked complexes requires 125I-FSH, specifically bound to the hormone receptor and cross-linking, and can be prevented with an excess of native FSH but not human choriogonadotropin. Complex formation was independent of blocking free sulfhydryl groups with N-ethylmaleimide. When the cross-linked complexes were reduced in the gel matrix and analyzed on fresh gels, the 76- and 62-kDa complexes were generated from the 110-kDa band, indicating the loss of two components. The lost components were estimated to be at 14 and 34 kDa. The rate of formation and cleavage of the cross-linked complexes indicated a sequential and incremental addition of 22-, 14-, and 34-kDa components to the FSH alpha beta dimer. The results of reduction of the cross-linked complexes demonstrate the existence of disulfide linkage between the three components.

Animals↗
PubMed1979

Receptor for bacteriophage lambda of Escherichia coli forms larger pores in black lipid membranes than the matrix protein (porin).

The receptor for phage lambda in Escherichia coli was isolated by cholate extraction and purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Protein bands corresponding to the monomer and the dimer were eluted from the gel and tested for their activity to inactivate phage lambda and to form pores in black lipid membranes. It was found that only the dimer inactivated phage lambda, whereas both the monomer and the dimer were active in forming pores. The pore characteristics were similar to those exhibited by the matrix protein (porin) (R. Benz, K. Janko, W. Boos, and P. Läuger, Biochim. Biophys. Acta 511:305--319, 1978). In comparison, the lambda receptor showed a somewhat higher degree of cation specificity, and its pore size was larger. Assuming that the thickness of the outer membrane is 7.5 nm and that the pore is an ideal hydrophilic channel, the pore diameter in vivo was estimated to be 1.6 nm for the lambda receptor and 1.2 nm for the matrix protein.

Bacterial Proteins↗
PubMed2003

Characterization of a slow-migrating component of the rabies virus matrix protein strongly associated with the viral glycoprotein.

We investigated multiple forms of rabies virus matrix (M) protein. Under non-reducing electrophoretic conditions, we detected, in addition to major bands of monomer forms (23- and 24-kDa) of M protein, an M antigen-positive slow-migrating minor band (about 54 kDa) in both the virion and infected cells. Relative contents of the 54-kDa and monomer components in the virion were about 20-30% and 70-80% of the whole M protein, respectively, while the content of the 54-kDa component was smaller (about 10-20% of the total M protein) in the cell than in the virion. The 54-kDa components could be extracted from the infected cells with sodium deoxycholate, but they were quite resistant to extraction with 1% nonionic detergents by which most monomer components were solubilized. The 54-kDa component was precipitated more efficiently than the monomer by a monoclonal antibody (mAb; #3-9-16), which recognized a linear epitope located at the N-terminal of the M protein. The mAb #3-9-16 coprecipitated the viral glycoprotein (G), which was demonstrated to be due to strong association between the G and 54-kDa component of the M protein. Monomers and the 54-kDa polypeptide migrated to the same isoelectric point (pI) in twodimensional (2-D) gel electrophoresis, implicating that the 54-kDa component was composed of component(s) of the same pI as that of the M protein monomers. From these results, we conclude that the M antigen-positive 54-kDa polypeptide is a homodimer of M protein, taking an N-terminal-exposed conformation, and is strongly associated with the viral glycoprotein. Possible association with a membrane microdomain of the cell will be discussed.

Animals↗
PubMed2005

An interaction between {alpha}v{beta}8 integrin and Band 4.1B via a highly conserved region of the Band 4.1 C-terminal domain.

alphavbeta8 Integrin is highly expressed in the vertebrate CNS, and mice lacking the alphav or beta8 genes develop cerebral hemorrhage due to defective interactions between blood vessels and alphavbeta8-expressing neural cells. Although alphavbeta8 binds many of the same extracellular matrix protein ligands as other integrins, very little is known about the intracellular signal transduction events used by alphavbeta8 to regulate CNS development. Here we identify Band 4.1B as an intracellular factor that interacts selectively with the beta8 cytoplasmic tail. The association with alphavbeta8 occurs via the band 4.1B C-terminal domain, a region highly conserved among the various Band 4.1 family members. Indeed, we show that beta8 integrin interacts directly with the C-terminal domains of several Band 4.1 proteins and colocalizes with them in cultured astrocytes and in the brain. These data identify a previously uncharacterized interaction between an integrin and Band 4.1 family members and suggest an important functional role for alphavbeta8-Band 4.1 interactions in the development and maintenance of the CNS.

Animals↗
PubMed2004

Detection of protease inhibitors by a reverse zymography method, performed in a tris(hydroxymethyl)aminomethane-Tricine buffer system.

A new detecting method for protease inhibitors, especially for low-molecular-weight inhibitors, is reported. Inhibitor samples were separated on a protein substrate-SDS-polyacrylamide gel in a Tris-Tricine buffer system that improves the separation and identification of peptides and low-molecular-weight proteins. After electrophoresis, the gel was incubated with the target proteases to hydrolyze the background protein substrate. The inhibitor bands, which were protected from proteolysis by the target proteases, were stained. Standard low-molecular-weight inhibitors, such as pepstatin A for pepsin or matrix metalloproteases inhibitor I for collagenase, as well as larger inhibitors, such as soybean trypsin inhibitor or aprotinin for tryspin and cystatin C for papain, were demonstrated by this method and showed clear blue inhibitor bands in the white background when the gels were treated with the target proteases. Some significant applications of this method are introduced. This method is an ideal system for discovering new protease inhibitors in small natural samples.

Buffers↗
PubMed2000

Interleukin-1beta and tumor necrosis factor-alpha decrease collagen synthesis and increase matrix metalloproteinase activity in cardiac fibroblasts in vitro.

We tested the hypothesis that the inflammatory cytokines can regulate fibroblast extracellular matrix metabolism. Neonatal and adult rat cardiac fibroblasts cultures in vitro were exposed to interleukin (IL)-1beta (4 ng/mL), tumor necrosis factor-alpha (TNF-alpha; 100 ng/mL), IL-6 (10 ng/mL), or interferon-gamma (IFN-gamma; 500 U/mL) for 24 hours. IL-1beta, and to a lesser extent TNF-alpha, decreased collagen synthesis, which was measured as collagenase-sensitive [(3)H]proline incorporation, but had no effect on cell number or total protein synthesis. IL-1beta decreased the expression of procollagen alpha(1)(I), alpha(2)(I), and alpha1(III) mRNA, but increased the expression of procollagen alpha(1)(IV), alpha(2)(IV), and fibronectin mRNA, indicating a selective transcriptional downregulation of fibrillar collagen synthesis. IL-1beta and TNF-alpha each increased total matrix metalloproteinase (MMP) activity as measured by in-gel zymography, causing specific increases in the bands corresponding to MMP-13, MMP-2, and MMP-9. IL-1beta increased the expression of proMMP-2 and proMMP-3 mRNA, suggesting that increased metalloproteinase activity is due, at least in part, to increased transcription. The effects of IL-1beta were not dependent on NO production. Thus, IL-1beta and TNF-alpha decrease collagen synthesis and activate MMPs that degrade collagen. These observations suggest that IL-1beta and TNF-alpha may contribute to ventricular dilation and myocardial failure by promoting the remodeling of interstitial collagen.

Animals↗
PubMedDate not supplied

Distribution of collagen deposition in cardiomyopathic hamster hearts determined by infrared microscopy.

Fibrillar collagens are major proteins of the cardiac extracellular matrix and play a significant role in the structural organization of the healthy heart. The aim of this study was (i) to investigate and compare the patterns of cardiac collagen deposition in different layers taken from both cardiomyopathic and normal myocardium using infrared (IR) microspectroscopy and (ii) to evaluate IR microspectroscopy as an alternative means for in vitro detection of collagen deposition in heart. Frozen sections from UM-X7.1 strain hamsters expressing the cardiomyopathic phenotype associated with ventricular remodeling and age-matched control (F1-beta) strain hamsters were examined using IR microspectroscopy. The presence of collagen was identified by the appearance of a typical collagen band at 1204 cm(-1), and the results were compared with identical tissue sections stained with trichrome, a routine discriminator for interstitial matrix proteins in cardiac myocytes. Spatial information addressing collagen deposition was obtained and viewed using contour mapping and three-dimensional band intensity maps at 1204 cm(-1). Perivascular and interstitial collagen deposition was detected in control samples taken from both ventricles as indicated with relative low intensities of the band of 1204 cm(-1). When compared with these control levels, the concentration of collagen was increased in cardiomyopathic left-ventricular samples with some focal depositions, and these results were confirmed with the trichrome references. Our study suggests that collagen deposition from normal and diseased hearts may be successfully analyzed directly in the absence of any chemihistological or immunological staining, by infrared microscopy.

Animals↗
PubMed1977

Nuclear matrix of HeLa S3 cells. Polypeptide composition during adenovirus infection and in phases of the cell cycle.

A subnuclear fraction has been isolated from HeLa S3 nuclei after treatment with high salt buffer, deoxyribonuclease, and dithiothreitol. This fraction retains the approximate size and shape of nuclei and resembles the nuclear matrix recently isolated from rat liver nuclei. Ultrastructural and biochemical analyses indicate that this structure consists of nonmembranous elements as well as some membranous elements. Its chemical composition is 87% protein, 12% phospholipid, 1% DNA, and 0.1% RNA by weight. The protein constituents are resolved in SDS-polyacrylamide slab gels into 30-35 distinguishable bands in the apparent molecular weight range of 14,000 - 200,000 with major peptides at 14,000 - 18,000 and 45,000 - 75,000. Analysis of newly synthesized polypeptides by cylindrical gel electrophoresis reveals another cluster in the 90,000-130,000 molecular weight range. Infection with adenovirus results in an altered polypeptide profile. Additional polypeptides with apparent molecular weights of 21,000, 23,000, and 92,000 become major components by 22 h after infection. Concomitantly, some peptides in the 45,000-75,000 mol wt range become less prominent. In synchronized cells the relative staining capacity of the six bands in the 45,000-75,000 mol wt range changes during the cell cycle. Synthesis of at least some matrix polypeptides occures in all phases of the cell cycle, although there is decreased synthesis in late S/G2. In the absence of protein synthesis after cell division, at least some polypeptides in the 45,000-75,000 mol wt range survive nuclear dispersal and subsequent reformation during mitosis. The possible significance of this subnuclear structure with regard to structure-function relationships within the nucleus during virus replication and during the life cycle of the cell is discussed.

Adenoviridae↗
PubMed1988

Characterization of matrix domains of the hamster acrosome.

In this study we describe the purification and the structural and biochemical properties of a detergent-stable complex of the hamster sperm acrosome. This complex consists of two distinct acrosomal matrix domains and a layer of electron-dense material, termed the acrosomal lamina, derived from the luminal surface of the outer acrosomal membrane. This complex has been isolated by centrifugation of detergent-extracted sperm suspensions on Percoll density gradients. The complex contains two major polypeptides of Mr 29,000 and Mr 22,000 and minor polypeptides of Mr 64,000-62,000, 56,000 and 35,000. Gelatin-containing sodium dodecyl sulfate-polyacrylamide gels demonstrate that bands of proteinase activity are not the major polypeptide components of the complex. These data demonstrate that the matrix of the acrosome is compartmentalized into domains of differing structural properties that occupy specific locations in the intact acrosome and that matrix components are physically associated with the outer acrosomal membrane. These data indicate that a structural framework is present within the acrosome and we speculate that it may be involved in sequestering hydrolases into specific spatial domains and could affect the temporal release of activity of selected hydrolases during the acrosome reaction.

Acrosome↗
PubMed2002

Expression and distribution of osteopontin and matrix metalloproteinase (MMP)-3 and -7 in mouse salivary glands.

We investigated the expression and distribution of osteopontin in mouse salivary glands. Western blot analysis showed intense positive bands at the predicted molecular mass (about 60 kDa) in mouse parotid and sublingual glands. However, a cross-reacted band around 30 kDa was strongly detected in submandibular glands. Indirect immunofluorescent analysis showed that osteopontin was localized at the luminal (apical) membranes of the acinar cells in parotid and sublingual glands. However, it was not detected in acinar cells of submandibular glands. No expression was found in ductal cells of any glands. We also examined the expression of matrix metalloproteinase (MMP)-3 and -7. In parotid gland, MMP-3 was observed at 57 kDa, indicating a latent form, but MMP-7 was not detected. In contrast, MMP-7 definitely was observed at 28 kDa area in submandibular gland, whereas MMP-3 was not detected. These results suggest that osteopontin localizes at luminal sites of acinar cells and may be associated with saliva secretion in mouse salivary gland. It is also suggested that osteopontin may be cleaved by MMP-7 in mouse submandibular gland.

Animals↗
PubMed1996

Cell surface phenotype and increased penetration of human multidrug-resistant ovarian carcinoma cells into in vitro collagen-fibroblasts matrix.

Human multidrug resistant ovarian carcinoma cells (A2780/ADR) exhibited increased in vitro penetration into the collagen-normal human fibroblasts matrix, increased cell surface expression of alpha 6 integrin (CD49f antigen) and slightly increased expression of alpha 2 (CD49b) integrin compared with that of parental drug-sensitive A2780 cells. Both, multidrug-resistant and parental, drug-sensitive, cell lines did not express the 67 kDa non-integrin high affinity laminin receptor on their cell surfaces. As there were no marked differences between metalloproteinase activity of both A2780 cell sublines (with similar intensity of 72 kDa and 92 kDa lysis bands in zymograms), the increased penetration of the drug-resistant subline into the collagen-fibroblast gel matrix might be associated with the increased expression of adhesion proteins (including collagen-binding alpha 2 integrin), or cell surface-associated collagenase-stimulating protein(s). This multidrug resistant ovarian carcinoma cell line might serve as an in vitro model of neoplastic cells with increased biological aggressiveness, molecular mechanisms of which require further analysis.

Antibodies, Monoclonal↗
PubMed2004

Extracellular bone acidic glycoprotein-75 defines condensed mesenchyme regions to be mineralized and localizes with bone sialoprotein during intramembranous bone formation.

Bone acidic glycoprotein-75 is expressed very early during in vivo models of intramembranous bone formation, highly enriched in condensing osteogenic mesenchyme after marrow ablation and the osteoprogenitor layer of tibial periosteum. Bone sialoprotein accumulates within bone acidic glycoprotein-75-enriched matrix areas at a later stage in both models. Decalcification of initial sites of mineralization consistently revealed focal immunostaining for bone acidic glycoprotein-75 underneath these sites suggesting that mineralization occurs within bone acidic glycoprotein-75-enriched matrix areas. Ultrastructural immunolocalization of bone acidic glycoprotein-75 does not support a direct association with banded collagen fibrils, but rather suggests it is a component of a separate, amorphous scaffold occupying interfibrillar spaces. Double immunogold labeling demonstrated that a sizeable proportion of bone sialoprotein particles were located within a 50-nm radius of bone acidic glycoprotein-75. These results define bone acidic glycoprotein-75 as the earliest bone-restricted, extracellular marker of osteogenic mesenchyme. Based on this early bone-restricted expression pattern and a previously documented propensity of bone acidic glycoprotein-75 to form supramolecular complexes through self-association, bone acidic glycoprotein-75 may serve a key structural role in setting boundary limits of condensing osteogenic mesenchyme.

Animals↗
PubMed2004

Changes in the spin state and reactivity of cytochrome C induced by photochemically generated singlet oxygen and free radicals.

This work compares the effect of photogenerated singlet oxygen (O(2)((1)Delta(g))) (type II mechanism) and free radicals (type I mechanism) on cytochrome c structure and reactivity. Both reactive species were obtained by photoexcitation of methylene blue (MB(+)) in the monomer and dimer forms, respectively. The monomer form is predominant at low dye concentrations (up to 8 microm) or in the presence of an excess of SDS micelles, while dimers are predominant at 0.7 mm SDS. Over a pH range in which cytochrome c is in the native form, O(2) ((1)Delta(g)) and free radicals induced a Soret band blue shift (from 409 to 405 nm), predominantly. EPR measurements revealed that the blue shift of the Soret band was compatible with conversion of the heme iron from its native low spin state to a high spin state with axial symmetry (g approximately 6.0). Soret band bleaching, due to direct attack on the heme group, was only detected under conditions that favored free radical production (MB(+) dimer in SDS micelles) or in the presence of a less structured form of the protein (above pH 9.3). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry of the heme group and the polypeptide chain of cytochrome c with Soret band at 405 nm (cytc405) revealed no alterations in the mass of the cytc405 heme group but oxidative modifications on methionine (Met(65) and Met(80)) and tyrosine (Tyr(74)) residues. Damage of cytc405 tyrosine residue impaired its reduction by diphenylacetaldehyde, but not by beta-mercaptoethanol, which was able to reduce cytc405, generating cytochrome c Fe(II) in the high spin state (spin 2).

Amino Acids↗
PubMed1995

Mapping of C-banded Crepis chromosomes by imaging methods.

Crepis capillaris is a highly suitable model plant for a computer-aided analysis of chromosomes because of its small number of chromosomes and well-defined bands. The identification of both large and small bands by means of profiles [grey value-function (position)] is frequently not possible with simple discrimination. In this case, dynamic curve fitting gives exact results by sliding discrimination. The application of low-pass filters, with a filter matrix size of 75 x 75 pixels, to the original image generates a reference image that can be used for sliding discrimination. The relevant bands are visible by the subtraction of the filtered image from the original image. The computerized bands correspond exactly to band regions recognized visually. Human vision is another approach to improve the quantification in cytogenetic results. The connection between the visual inspection and the imaging methods will reduce the subjective interpretation of individual researchers. The knowledge-based analysis may be a significant factor in the near future to answer unsolved questions.

Chromosome Banding↗
PubMed2000

Bacterial poly(3-hydroxybutyrate): an optical microscopy and microfocus X-ray diffraction study.

Two-dimensional spatially resolved microfocus X-ray diffraction has been used to investigate spherulites of pure bacterial poly(3-hydroxybutyrate) (PHB) and of a blend of natural and synthetic atactic PHB (a-PHB) crystallized at a relatively high temperature (Tc = 140 degrees C). Both samples investigated contained practically two-dimensional spherulites, characterized by wide extinction bands (band spacing > 80 microns). The X-ray diffraction patterns confirmed that the unit cell alpha-axis is oriented along the spherulite radius in PHB and that the same is true for the a-PHB containing blend. Comparison of the matrix of diffraction patterns with the polarized optical micrograph of the scanned sample area indicated a very clear correlation between pattern changes and banding, yielding a straightforward picture of the structural variations within the spherulite.

Bacteria↗
PubMed1999

Analysis of Line Positions and Strengths of H216O Ground and Hot Bands Connecting to Interacting Upper States: (020), (100), and (001).

High-resolution spectra of H216O were recorded with a Fourier-transform spectrometer covering transitions in the (020)-(010), (100)-(010), and (001)-(010) bands from 1100 to over 2300 cm-1. Also included in the study were previously reported measurements of these bands and measurements of the (020)-(000), (100)-(000), and (001)-(000) bands from 2620 cm-1 to 4500 cm-1. The linestrengths were fitted to a model which takes into account the interactions between the vibrational states (020), (100), and (001). The model included dipole moment matrix elements (also referred to as transition elements) represented by 19 expansion coefficients for B-type transitions and 14 expansion coefficients for A-type band transitions. The most satisfactory results were obtained when the relative signs and values of the leading dipole moment terms of each of the three "hot" bands were as follows: u(020-010) = 1.936(97) x 10(-1) D, u(100-010) = 3.876(19) x 10(-2) D, and u(001-010) = 2.523(75) x 10(-2) D. Hot water emission experimental frequencies from other studies were included in an analysis to obtain rotational energies for levels up to high J and/or Ka of the (020), (100), and (001) vibrational states. The results from this study provide a more accurate representation of the parameters than those available at present for the six bands. Copyright 1999 Academic Press.

Journal Article↗
PubMed2005

The orange-brown patina of Salisbury Cathedral (West Porch) surfaces: evidence of its man-made origin.

GOAL, SCOPE AND BACKGROUND: In this paper, we attempt to elucidate the composition and origin of the orange patina on the surfaces of the West-Porch of Salisbury Cathedral by comparison to other known patinas: (i) the orange-brown patina on the marble surfaces of the Acropolis in Athens and the Arch of Titus in Rome whose analyses have shown very high amounts of phosphates, and generally amino acids from animal-skin glue or other protein binders; (ii) the phosphated patinas which also contain oxalates, found in 1996 on Catalonian calcareous sandstones and in the calcareous dolomites of the Monastery of Silos, Spain, whose origin is either the application of calcium caseinate, or egg yolk and animal glue; and (iii) the patinas with only oxalates found in some of Verona's monuments (St. Zeno) and Spanish sites as in the Monastery of Guadalupe and Cuenca cathedral, formed either by the mineralization of algal filaments or by biological reactions yielding oxalate from yolk egg (added to stone as part of preservative empirical treatments). METHODS: In the winter of 2003, the West-Porch of Salisbury Cathedral received conservation works, but the old patina was not entirely removed. This fact has allowed us to collect the samples for its study. The IR spectra were registered with a Golden Gate ATR Mk II system using attenuated total reflectance Fourier transform infrared (ATR/FTIR) spectrometry. Mineral composition was determined by XRD (Philips PW 1710 spectrometer with Cu tube), whereas major and trace elements analyses were performed by XRF (Philips PW1480 PW). Microscopy examination was performed on a Leica M655 microscope. Phosphate, oxalate, calcium and sulphate contents were analysed by usual chemical methods. RESULTS: ATD-FTIR spectra of the Salisbury's patina exhibit peaks at 2361, 2341 and 671 cm(-1) (assigned to phosphates); 3410, 1680, 1620, 1122 and 602 cm(-1) (assigned to sulphates); and 1447/1437 and 876 cm(-1) (attributed to carbonates). The little peaks at 1620 and 798 cm(-1) could be assigned to oxalates. XRD and XRF have led to identify the carbonates, phosphates and sulphates as pertaining to the species dolomite, hydroxyapatite and gypsum, respectively. Oxalates are detected only in small amounts by chemical analyses but wewellite and weddellite have not been well identified. The interface between the patina and the calcareous dolomite is very uneven and full of cavities in certain cases, but well-defined and rather smooth in other cases. In accordance with the very small amounts of the oxalates found, remnants of micro-organisms are not detected in the patinas. DISCUSSION: The Salisbury's patina is a composite material formed by particulates and matrix constituents. Regarding the patina particulate, e.g. animal bones, it is necessary to refer to the apatite phase composition. The bone mineral contains 4-8 wt % of carbonate in animal body and its presence in the apatite phase is advantageous as it increases the mechanical strength. We think that FTIR bands at around 1440 and 876 cm(-1) arise from vibration of CO3(2-) ions, but not necessarily from the limestone. They could be attributed to carbonated hydroxyapatite through the substitution of groups PO4(3-) for CO3(2-) in the lattice of hydroxyapatite. Concerning the matrix and also from the FTIR spectra, the absence of specific bands of the following species: proteins (3350-3225, 1660, 1550-1535, 1270-1230 and 620 cm(-1)), oils (1778, 1738 and 1051 cm(-1)), bee waxes (3000, 1470, 720-730 and 1700 cm(-1)) and aged egg-yolk (2954, 2920, 2850, 1650, 1549, 1465 and 1240 cm(-1)) had led us to exclude these usual binders. On the other hand, the amount of sulphates in the paste that covers the walls of the Salisbury's Cathedral is excessively high (above 20% in weight) to consider it as a biotransformation product of calcium oxalate from fungal biofilms. Consequently, we must think that the gypsum found in the samples has a man-made origin (it was deliberately added as part of a protective paste) and that it is the matrix searched for. Thus, we deduce that the patina of Salisbury's Cathedral is a special stucco made mixing plaster with powdered bone (the colour of the bones is the same that it exhibits in the patina), low quantities of an uncharacterized binder (collagen, possibly) and water. CONCLUSION: We believe that the patina of the Salisbury's Cathedral is a variant of the Greco-Latin empirical protective treatment that included bone as a hardening material. Nevertheless, we also think that the presence of the bones in the paste could be related to an aesthetical intention: gaining a warm tone for the original stone through the ochre colour of the bones. RECOMMENDATION AND PERSPECTIVE: Our results have been an excuse to contribute to the controversy started at the 80's on the origin of orange-brown patinas observed on stone surfaces of Greco-Latin and medieval monuments. There are two major theories on provenance: biological vs. man-made. In Salisbury Cathedral, neither of them has been proven through scientific evidence as yet. Our opinion is that Salisbury patina can be classified into the man-made group.

Calcium Carbonate↗