Lead antimonate yellow, or Naples Yellow, is one of the most common yellow pigments in Western European art. It was used mainly in the period from 1500 to 1850. During the 18th and 19th centuries, a ...whole range of production recipes was published. However, the early production history of the pigment is not well understood. In this paper, a study of two early production recipes is reported. Under the nomenclature of potters’ yellow, the recipes describe some production details of the pigment. Reconstructions of the historical lead antimonate yellow were made according to these sources. X‐ray powder diffraction (XRPD) was used to examine the reaction products. Our findings show that various types of lead antimonate yellow can be formed, following the descriptions given in the recipes. Some of these types, notably lead–tin antimonate, have been found in earlier studies of authentic works of art. No evidence was found for a locally limited use of this pigment, as has previously been suggested. Documentary and analytical evidence indicates that the knowledge on lead antimonate yellows originates from Middle Eastern ceramic and glass industries. It is argued that the know‐how on the production of lead antimonate yellows has been transferred via the migration of glass artists from the Eastern Mediterranean to Venice during the 15th century.
We determined the effect of several concentrations of cadmium (0, 5, 10, and 20 μg/l) on cellular viability in the microalgae Scenedesmus sp. and Dunaliella viridis, by measuring growth at 0, 24, 48, ...72, and 96 h and pigment production at 10 days. Algae were obtained from the Nonvascular Plant Laboratory collection, in the Facultad Experimental de Ciencias, Universidad del Zulia, Venezuela. Growth was measured by cellular counting, while pigment content was evaluated using conventional spectrophotometric techniques. Growth of both species decreased in the exposed cultures comparing with the control, but its behavior was similar, because in both control and exposed cultures, its was observed an adaptive phase in the first hours, as well as a growth phase after 72 h. Cadmium concentrations above 10 μg/l produced an adverse effect on pigment production, depending on the concentration and/or exhibition time. However, even though cadmium inhibited growth and pigment production, levels of both parameters indicated cellular viability, demonstrating the adaptability of the algae cultures when they were exposed to the metal.
Summary
Malassezia (M.) furfur, a commensal organism found on the human skin, produces a wide range of pigments and fluorochromes when cultured with tryptophan as a sole nitrogen source. Some ...compounds of this pigment metabolism may provide an explanation for clinical characteristics of pityriasis versicolor (PV), a frequent skin disease in humans characterised by long‐lasting pigmentary changes. Malassezia globosa is currently regarded as the causative agent of PV, but tryptophan‐dependent pigment production has not yet been demonstrated in this species. In a previous study, we identified M. furfur genes that were differentially expressed 3 and 5 h, respectively, after induction of tryptophan‐dependent pigment production. The recent publication of the genome of M. globosa prompted us to check the M. furfur sequences for homologues in M. globosa. The 3‐h pool contained 79 sequences and the 5‐h pool contained 91 sequences. A translated vs. translated BLAST search resulted in 62 sequences (78%) of the 3‐h pool and 61 sequences (67%) of the 5‐h pool showing similarity to a sequence from M. globosa. It appears that M. globosa possesses homologues to most of the genes that are differentially expressed during pigment production in M. furfur.
Production of red pigments (naphthoquinones) by the insect pathogenic fungus Cordyceps unilateralis BCC 1869 was investigated in this study. Cultivation conditions, including temperature, intitial pH ...of medium, and aeration, were optimised to improve the yield of total naphthoquinones in shake-flask culture of C. unilateralis. The highest yield of total naphthoquinones (3 g L-1) was obtained from a 28-day culture grown in potato dextrose broth with an initial pH of 7.0, at 28 °C with shaking-induced aeration at 200 rpm. An extraction process for isolation of the targeted naphthoquinone, 3,5,8-trihydroxy-6-methoxy-2-(5-oxohexa-1,3-dienyl)-1,4-naphthoquinone (3,5,8-TMON), from a culture of C. unilateralis, was also developed. The yield of 3,5,8-TMON obtained was about 1.2 g L-1 or 40% of total naphthoquinones. The stability of 3,5,8-TMON was very high, even upon exposure to strong sunlight (70,000 lx), high temperature up to 200 °C, and acid and alkali solutions at concentrations of 0.1 M.
Background, aim, and scope
The aim of this work was to determine phytotoxicity of washing waste-waters from a cutlery production line with high content of Cr and Ni. These waters were previously ...classified, without verification, as dangerous and it is now necessary to question the justice of the present classification under the new legislation for waste management (Waste Law No. 223/2001) in the Slovak Republic.
Methods
Young seedling of the dicotyledon terrestrial plant mustard
Sinapis alba
L. were used for determination of the dry and fresh root and shoot biomass and photosynthetic pigment production. Observed parameters were evaluated in laboratory experiments with three types of washing waste-waters from a cutlery production line. All contamination of tested washing waste-waters came from heavy metals (Ni, Cr), non-polar extractable compounds (NEC; residues of oils and waxes from polishing of stainless steel cutlery) and detergents (used for cutlery degreasing). Photosynthetic pigments (chlorophyll a, b, and total carotenoids) were extracted in 96% ethanol and measured spectrophotometrically at 665, 649, and 470 nm. All phytotoxicity tests were carried out in triplicate, and they included a control in tap water.
Results
All tested washing waters reduced root dry mass, whereas the shoot dry mass was either unaffected or it increased. The tested washing waters’ effect was stronger on fresh mass production than on dry mass production. This indicated problems in water reception and translocation. The adverse effect on photosynthetic pigments production increased only slowly with remaining washing waste-water concentration. Almost all Chl a/b ratios were the same as for the control and this indicated no significant differences in the reduction of either a or b chlorophylls. As opposed to chlorophylls, carotenoids content increased in the presence of tested washing waste-waters and equaled or exceeded their content in the control. As the ratio of Chl(a + b)/Car was lower than that for the control for almost all tested samples, a stronger reduction in chlorophylls than in carotenoids was confirmed.
Discussion
The phytotoxicity of waste-waters from cutlery production line washing reservoirs was evaluated and the effects on dry and fresh mass production and photosynthetic pigments amount was discussed as Cr and Ni toxicity.
Conclusions
It is concluded from the present study that washing waste-waters from cutlery production line are quite toxic to plants, thus reducing biomass and photosynthetic pigment production and influencing water translocation through the plant.
Recommendations and perspectives
These determined adverse effects of washing waste-waters from this cutlery production line classified them as too dangerous to be spread on open-land soil. On the basis of this study, high toxicity of the presented waste-waters from metal surface-finishing as well as justness of their liquidation as hazardous wastes by legally assigned persons were recommended.
Serratia marcescens biovar A2/A6, isolated from an Indonesian freshwater source, was identified based on extensive morphological, biochemical and genetic characterization. Formation of pigment was ...found to be strongly influenced by environmental conditions. Placket-Burman design was used to analyze the effect of carbon and nitrogen sources. Based on results of physiological and biochemical studies, the optimum conditions for growth and pigment formation were incubation 30 degree C in a neutral to slightly alkaline medium containing lactic acid and beef extract.
An isolate of Dunaliella salina (DUNS-1) and other two isolates (DUNS-2 and DUNS-3), collected from coastal lagoons with 14 and 30% (w/v) of NaCl, respectively, were analyzed under different saline ...conditions. Glycerol (380 mg l⁻¹) and carotene (5.9 mg l⁻¹) contents for DUNS-2 were 0.3 and 10 times higher than DUNS-3, even though both isolates were collected from the same lagoon and share a similar ribosomal DNA sequence.
The
lly locus confers fluorescence, haemolysis, brown pigmentation and an increased resistance to light in
Legionella pneumophila. In this study, we correlated the pigment production of two
...lly-positive
L. pneumophila isolates and a recombinant
lly-positive
Escherichia coli strain with the presence of homogentisic acid (HGA) in the culture supernatant. The detection of HGA by high performance liquid chromatography and the data analysis of the deduced amino acid sequence of the
lly gene indicate that the
lly locus codes for a
p-hydroxyphenylpyruvate dioxygenase (HPPD). This enzyme catalyses the transformation of
p-hydroxyphenylpyruvate into HGA, which subsequently oxidises and polymerises into a melanin-like pigment. One open reading frame (ORF 1) in the
lly region exhibited homologies with genes of
Synechocystis sp.,
Petroselium crispum and
Streptomyces mycarofaciens that code for methyltransferases. By screening a genomic library of
L. pneumophila (serogroup 1) strain Corby with a monoclonal antibody against the legiolysin (
lly), we identified two recombinant
E. coli clones that did not produce the brown pigment and showed no haemolysis and fluorescence. DNA sequencing revealed that both clones contained 874 nucleotides of the N-terminal part of the
lly gene. The recombinant strains expressed truncated legiolysin proteins of 39.5 and 35.7 kDa and did not produce HGA. Considering the highly conserved structure of legiolysin-like HPPD genes from other organisms, we suggest that the C-terminus of the legiolysin may be essential for the enzymatic activity that conferred pigmentation via HGA polymerisation, haemolysis and fluorescence.
Integrated fermentation–separation processes using a polymeric adsorbent were investigated to increase the productivity of red pigment. Resin HP-20 was chosen for polymeric adsorbent, taking into ...consideration the adsorption capacity and the desorption ability. The maximal production of total pigment was obtained when the HP-20 resin was added after 10 h. As the amount of resin was increased from 5 to 20% (v/v), cell growth gradually decreased. The maximal production of pigment was obtained when 10% (v/v) HP-20 was added and the concentration of pigment contained in the resin was 5.92 g/l. The extractive fermentation was carried out in bioreactors equipped with extractive columns packed with 5, 10 and 20% (v/v) HP-20. Cell growth decreased inversely in proportion to the concentration of HP-20 packed into the extractive column. The maximal production of pigment (6.92 g/l) was obtained with 10% (v/v) HP-20. The bioreactor equipped with an extractive column packed with HP-20 adsorbent resin showed higher productivity than the conventional batch bioreactor. A 31% increment of pigment production was obtained in extractive fermentation, compared with the simple batch culture.
