Tribute in memory of Jacques Breton (1942-2018).

Jacques Breton spent his 39 years of professional life at Saclay, a center of the French Atomic Energy Commission. He studied photosynthesis with various advanced biophysical tools, often developed by himself and his numerous coworkers, obtaining a large number of new information on the structure and the functioning of antenna and of reaction centers of plants and bacteria: excitation migration in the antenna, orientation of molecules, rate of primary reactions, binding of pigments and electron transfer cofactors. Although it is much too short to illustrate his impressive work, we hope that this contribution will help maintaining the souvenir of Jacques Breton as an active and enthusiastic person, full of qualities, devoted to research and to his family as well. We include personal comments from N. E. Geacintov, A. Dobek, W. Leibl, M. Vos and W. W. Parson.

In-situ fluorimetry: a powerful non-invasive diagnostic technique for natural dyes used in artefacts. Part II. Identification of orcein and indigo in Renaissance tapestries.

In this paper, three Renaissance tapestries depicting scenes painted by Raffaello Sanzio, conserved at the Vatican Museum, were investigated using in-situ UV-Visible fluorimetric measurements. The results show that this technique is suitable for the detection of natural organic colorants used for dyeing the threads woven in these tapestries. The emission signals detected on red-purple colours were assigned to the colorant orcein and those on different nuances of blue and green colours to indigo by comparison with data from reference laboratory samples. The assignments were supported by chromatographic experiments carried out on threads taken from the back side of the tapestry in the same points analysed by spectrofluorimentry.

Red pigments and Boraginaceae leaves in mortuary ritual of late Neolithic China: A case study of Shengedaliang site.

Investigation of mortuary ritual is an important method to reconstruct many aspects of past societies. Due to the lack of relevant analytical work, little evidence related to organic materials in a burial can be found in China. Here we report materials collected from a burial during the excavation of the Shengedaliang site. The recovered materials were analyzed using Raman spectroscopy and plant analysis: flotation, pollen and phytolith analysis. The red pigments found scattered over the human remains were identified as cinnabar. Extracted phytoliths associated with the burial are mainly leaves from the Boraginaceae family. This is the first time that a covering of leaves have been identified with a burial in Neolithic China. The presence of "special" leaves fossil may indicate a type of "plant worship" and the identification of an important plant used in traditional Chinese medicine. The finding of the two materials allows us to better identify indicators of funerary ritual and its relationship to social inequality.

Sir William Osler's perceptions of urolithiasis and the case of the indigo calculus.

BACKGROUND: Sir William Osler published his textbook, The Principles and Practice of Medicine, in 1892. It became the definitive treatise on a wide variety of diseases. The section on nephrolithiasis clearly presents the etiology, pathology, symptoms, diagnosis, and treatments. What remains a mystery is the mention, under rare forms of human stones, of a type called "indigo." MATERIALS AND METHODS: A search of Index Medicus starting from 1909 backward to its inception in 1879 was performed for key words "indigo," "calculus," "renal" or "bladder stones" and "indicanuria." Twelve textbooks of urology published before 1940 were scrutinized for references to indigo calculi. RESULTS: Only two references to indigo were found, both related to its use for treating constipation (1887 and 1891). Of the 12 textbooks, only 4 make passing reference to "indigo stones." They all mention that such calculi are very rare, but direct references to cases are lacking. One textbook references a study of blue stones from Egyptian mummies. CONCLUSION: It is unlikely that Osler's reference to an indigo calculus was taken lightly during his writing of The Principles and Practice of Medicine. The case of the indigo calculus is fascinating and perhaps enlightening if only for the source of Osler's intrigue.

Raman spectroscopic analysis of the Maya wall paintings in Ek'Balam, Mexico.

Raman spectroscopy has been applied to the examination of wall painting fragments from the archaeological site of Ek'Balam (Yucatán, Mexico). Thirty-three samples have been studied, all originating from room 23 of the Acropolis, and being representative of the painting technique at Ek'Balam during the late Classic Maya period. Several pigments such as haematite, calcite, carbon, cinnabar and indigo were identified in these samples. The latter pigment was presumed to be present as 'Maya blue', which is an intercalation product of indigo and palygorskite clay. The observed Raman spectra are reported and some band assignments have been made. This survey is the first Raman spectroscopic examination of a whole set of pigments in archaeological Maya wall painting fragments.

Improvements in the wallpaper industry during the second half of the 19th century: micro-Raman spectroscopy analysis of pigmented wallpapers.

Scientific studies of the pigments used in the manufacturing process of some pigmented wallpapers are presented in this work. Non-destructive micro-Raman spectroscopy was selected for this purpose, and provides important information about how the 19th century wallpaper industry incorporated new materials in their works and designs. At the same time, analysis can help to date the samples of uncatalogued wallpapers. Chrome yellow, burnt Sienna, Prussian blue, ultramarine blue, red lead, carbon black, calcium carbonate, red iron oxide and a red organic pigment were identified. According to the palette used, as well as to the manufacturing process, the wallpapers in this study can be dated to the second half of the 19th century.

Raman spectroscopic library of natural and synthetic pigments (pre- approximately 1850 AD).

To assist in the greatly increasing number of applications of Raman microscopy as a tool for non-intrusive, in situ archaeometric analysis, the Raman spectra of over 60 pigments, both natural and synthetic, known to have been in use before approximately 1850 AD, have been studied by Raman microscopy. Fifty-six pigments have yielded high quality spectra which have been arranged, by colour, into a spectroscopic library for reference purposes. The spectroscopic files may be downloaded from http:/(/)www.ucl.ac.uk/chem/resources/raman/speclib .html.

Characterisation of pigments and corrosion patinas by means of micro-Raman spectroscopy.

New applications of micro-Raman spectroscopy are presented here for the investigation of colouring agents in a wax model of plant and of corrosion products on metal artworks. A late 1700 wax model of Camellia japonica L. was studied in order to characterise the nature of white, red and green colours of petals and leaves. White and red colours of petals were identified as pigments of baryte and a mixture of cinnabar and carmine lake, respectively. Fragments taken from leaves with different green hues were also studied; only yellow grains were isolated in this case which were identified as orpiment and yellow chrome. The applicability of micro-Raman spectroscopy to the study of corrosion products on metal objects is presented here for iron archaeological artefacts and for lead samples taken from the cupolas of the Consolata Sancturay in Turin. Analysis of blackish and reddish corrosion patinas entirely covering the archaeological iron objects led to the identification of magnetite and maghemite, goethite and lepidocrocite, respectively. As to lead fragments, the main corrosion product was lead sulphate, and minor amounts of lead carbonate, nitrate and oxide (litharge) were also found.

Study of the vibrational spectrum of cuprorivaite.

In this research, after tracing a history of the pigment, the preparation and analysis of samples of Egyptian blue have been reported. The main reactions taking place during its preparation are indicated. X-ray diffractions show that, starting from mixtures of precursors with stoichiometric composition, the product is practically only cuprorivaite. The kind of flux and cristallinity of silica does not seem determining factors for the pigment formation. Infrared and Raman spectra and an assignment of the bands are reported. Impurities ascertained are discussed on the basis on the data available.

Copper resinate: preparation, characterisation and study of degradation.

This paper describes a method for the synthesis of Copper Resinate, which disappeared from artists' palettes in the eighteenth century. This was carried out by interpreting ancient recipes following a scientific approach. Its characterisation using Fourier Transform-Infrared Spectrometry and Gas Chromatography-Mass Spectrometry demonstrated that it is a mixture containing copper and oxidised abietic acids, mainly dehydroabietic and 7-oxo-dehydroabietic acids, formed during the preparation of the pigment and the curing of the paint layer. The composition of copper resinate paint layers, artificially aged by U.V. irradiation at 365 nm (UV), heating (T), and exposed to atmospheric pollutants (NOX) in a climatic chamber, was investigated. The combination of irradiation and temperature produced a change in colour along with a significant increase in the recovered amount of 7-oxo-dehydroabietic acid. The identification of copper resinate in a sample from an old painting should be related to the presence of the following resin compounds which are stable in the ageing process: dehydroabietic and 7-oxo-dehydroabietic acid pimaradienic acids. Photo-oxidation of the resin acids co-ordinated with copper seem to be the most probable decay mechanism responsible for the colour change in the pigment.

Muriel Wheldale Onslow and early biochemical genetics.

Muriel Whedale, a distinguished graduate of Newnham College, Cambridge, was a member of William Bateson's school of genetics at Cambridge University from 1903. Her investigation of flower color inheritance in snapdragons (Antirrhinum), a topic of particular interest to botanists, contributed to establishing Mendelism as a powerful new tool in studying heredity. Her understanding of the genetics of pigment formation led her to do cutting-edge work in biochemistry, culminating in the publication of her landmark work, The Anthocyanin Pigments of Plants (1916). In 1915, she joined Frederick Gowland Hopkin's Department of Biochemistry as assistant and in 1926 became one of the first women to be appointed university lecturer. In 1919 she married the biochemist Huia Onslow, with whom she collaborated until his death in 1922. This paper examines Whedale's work in genetics and especially focuses on the early linkage of Mendelian methodology with new techniques in biochemistry that eventually led to the founding of biochemical genetics. It highlights significant issues in the early history of women in genetics, including the critical role of mentors, funding opportunities, and career strategies.

The first known use of vermillion.

Vermillion has been shown to be useful in preserving human bones from 5000 years ago. Remarkably well-preserved human bones have been found in the dolmenic burial 'La Velilla' in Osorno (Palencia, Spain), carefully covered by pulverized cinnabar (vermillion) which ensured their preservation even in non-favorable climatic conditions. We believe the red powder was deliberately deposited for preservative use because no cinnabar mine is to be found within 160 km, because of the large amount (hundreds of kilograms) used, and because its composition, red mercuric sulphide, is similar to that of preparations used in technical embalming. This finding pushes back the data of the use of mercury ore for preservation by four millennia in South America, and by at least one millennium in the Old World. Chemical and thermal analyses of vermillion in La Velilla have demonstrated its great purity and shown that the cinnabar was pulverized and washed (but not heated), producing a bright red-orange tone.

Identification of copper-based green pigments in Jaume Huguet's Gothic altarpieces by Fourier transform infrared microspectroscopy and synchrotron radiation X-ray diffraction.

The scientific investigation of ancient paintings gives a unique insight into ancient painting techniques and their evolution through time and geographic location. This study deals with the identification of the green pigments used by one of the most important Catalan masters in Gothic times, Jaume Huguet. Other pigments and materials have also been characterized by means of conventional techniques such as optical microscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. Synchrotron radiation X-ray diffraction has been used to produce maps of phases at a spatial resolution of 100 microm across chromatic layers.

The emergence of pigment cell biology: a personal view.

This is a semi-autobiographical coverage of my research career in pigment cell biology presented in the context of the emergence and growth of the discipline. This anecdotal presentation tells about some historical personages in the field. My undergraduate studies at the University of Rochester are related to my graduate work at the University of Iowa. I tell how my dissertation research was derived from a marriage between my interests in experimental embryology and the new field of comparative endocrinology. My early years of research at Iowa and as a young faculty member in Zoology at the University of Arizona were much concerned with the evolution of our knowledge of the chemistry and biology of melanocyte-stimulating hormone (MSH), especially concerning the pigment cells of lower vertebrates. Our developmental, structural, functional, and biochemical characterization of vertebrate chromatophores is described, as is our elucidation of the dermal chromatophore unit. The direct effects of light on changes in pigmentation are considered in descriptions of both the tail-darkening reaction and the role of the pineal gland in melanophore control. Emphasis is placed on the developmental biology of pigmentation, especially on the concept that all pigment cells are derived in common from a stem cell of neural-crest origin, whose expression is influenced by factors, such as melanization-inhibiting factor (MIF), localized in specific areas of the skin to thus produce specific pigmentation patterns. This research is considered in light of what is known about the agouti locus and MSH in the expression of mammalian pigmentation patterns. Part of my work has included ecological considerations, and some of this is touched upon. My role as founder of the journal 'Pigment Cell Research', is presented briefly, as is my involvement in the XIIIth International Pigment Cell Conference and in the establishment of both the International Pigment Cell Society and the International Federation of Pigment Cell Societies. Finally, I comment on the future of research in pigmentation.