Search

This study aims to investigate the seasonal and spatial distribution of surface phytoplankton communities in the Baltic Sea, using pigment analysis and hydrological parameters. Data were collected during six oceanographic campaigns between 2005 and 2008, including high-performance liquid chromatography (HPLC) pigment characterization and hydrological measurements. The first part of this comprehensive study was focused on the HPLC phytoplankton pigment dataset in relation to hydrological conditions. The research highlighted the importance of high-quality input data for accurate taxonomic analysis. Several unsupervised machine learning approaches, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), and network-based community detection analysis (NCA), were used to analyze the data and identify phytoplankton communities based on biomarker pigments. Five main phytoplankton communities were identified: diatoms, dinoflagellates, cryptophytes, green algae, and cyanobacteria. The results evidenced distinct seasonal patterns, with diatom blooms dominating in spring, cyanobacterial blooms in mid-summer, and haptophyte and dinoflagellate peaks occurring in late summer and autumn. While PCA and NCA provided consistent insights into community structure, HCA offered less clarity in distinguishing between groups. The results of the statistical analysis were then compared with those of traditional approaches such as CHEMTAX and region-specific bio-optical algorithms, providing new perspectives on the taxonomic composition of phytoplankton groups. This study provides valuable insights into phytoplankton dynamics in the Baltic Sea and the effectiveness of different analytical approaches in understanding community structure, providing metrics that can enhance current and future advancements in remote sensing, including support for hyperspectral ocean color remote sensors. [ABSTRACT FROM AUTHOR]

Synthetic biology has advanced in creating artificial microbial and algal communities, but technical and evolutionary complexities still pose significant challenges. Traditional methods, like microscopy and pigment analysis, are limited in throughput and resolution. In contrast, advancements in full-spectrum cytometry enabled high-throughput, multidimensional analysis of single cells based on size, complexity, and spectral fingerprints, offering more precision and flexibility than conventional flow cytometry. This study uses full-spectrum cytometry to analyze synthetic algal–microbial communities, enabling rapid species identification and enumeration. The workflow involves recording individual spectral signatures from monocultures, using autofluorescence to capture populations of interest, and creating a spectral library for further analysis. This spectral library was used for the analysis of the synthetic phytoplankton communities, revealing differences in spectral signatures. Moreover, the synthetic consortium experiment monitored algal growth, comparing results from different instruments, highlighting the advantages of the spectral virtual filter system for precise population separation and abundance tracking. By capturing the entire emission spectrum of each cell, this method enhances understanding of algal–microbial community dynamics and responses to environmental stressors. The development of standardized spectral libraries would improve the characterization of algal communities, further advancing synthetic biology and phytoplankton ecology research. [ABSTRACT FROM AUTHOR]

Two ideas, proposed by Thomas Young and James Clerk Maxwell, form the foundations of colour science: (i) three types of retinal receptors encode light under daytime conditions, and (ii) colour matching experiments establish the critical spectral properties of this encoding. Experimental quantification of these ideas is used in international colour standards. However, for many years, the field did not reach consensus on the spectral properties of the biological substrate of colour matching: the spectral sensitivity of the cone fundamentals. By combining auxiliary data (thresholds, inert pigment analyses), complex calculations, and colour matching from genetically analysed dichromats, the human cone fundamentals have now been standardized. Here, we describe a new computational method to estimate the cone fundamentals using only colour matching from the three types of dichromatic observers. We show that it is not necessary to include data from trichromatic observers in the analysis or to know the primary lights used in the matching experiments. Remarkably, it is even possible to estimate the fundamentals by combining data from experiments using different, unknown primaries. We then suggest how the new method may be applied to colour management in modern image systems. [ABSTRACT FROM AUTHOR]

Material analysis was carried out on four manuscripts from Northern Thailand, which included two palm-leaf manuscripts and two paper manuscripts. The two palm-leaf manuscripts MS 6 and MS 7 were found to have been written in the traditional method, wherein text was incised on the surface of the leaves, and then soot applied to the surfaces, confirmed by the identification of carbon ink. MS 7 additionally showed the presence of trace levels of iron in the ink, either from soot paste or from the stylus used for inscribing. The paper manuscript MS 3 was written in iron-gall ink, with sections written using a methyl-violet based ink while MS 4 was written in carbon ink. The paper used in the case of MS 3 was found to be machine made, while khoi fibres (Streblus asper) were used for making the paper used for MS 4. A combination of traditional and modern pigments, like molybdenum orange, was used for decorating the edges and cover. The results improved our understanding of these manuscripts in particular, and also provided us with insights about the rapid adoption of modern materials and their incorporation into the production of written artefacts from Northern Thailand in the late 19th and early 20th centuries. [ABSTRACT FROM AUTHOR]

A marine amphoroid diatom, responsible for blooms in 2011 and 2019 in French Atlantic waters was studied using morphology and molecular phylogeny. The highest cell concentrations were reached in the region of Marennes Oléron on 19 August 2011 and were related to a greyish discolouration of gills of oysters and mussels. It was identified as Amphora ostrearia var. minor Grunow, based on morphological characteristics. To ensure the correct identification, type material was re-investigated, using the type slide n° 142 (Cleve & Möller 1878. Diatoms. Part II. Esatas Edquists Boktryckeri, Upsala: 49–108) that enabled us to establish the identity of the taxon. Plastid morphology corresponded to Mereschkowsky's type 8 amphoroid chloroplast, a feature typical for the genus Tetramphora Mereschkowsky. Results of a phylogenetic analysis inferred from a concatenated alignment including the nuclear marker SSU and the chloroplast rbcL indicated that A. ostrearia var. minor was positioned inside the monophyletic clade Tetramphora (Mereschkowsky) Stepanek & Kociolek. This, together with the morphological data, necessitated a transfer of A. ostrearia var. minor Grunow to the genus Tetramphora (Mereschkowsky) Stepanek & Kociolek. In addition, the genetic distances (p-values) from SSU–rbcL sequences were estimated among the species of Tetramphora including T. ostrearia, the generitype. These revealed that the divergence between Tetramphora ostrearia (Brébisson) Mereschkowsky and its variety minor was higher than the mean value within species of the genus. As a consequence, the studied taxon is raised to the species level as Tetramphora minor (Grunow) Nézan, comb. et stat. nov. Toxin analysis of four strains of T. minor revealed the absence of domoic acid production. Pigment analysis of T. ostrearia revealed a high fucoxanthin production, similar to other amphoroid species. [ABSTRACT FROM AUTHOR]

• Pigment provenance research is a promising direction in cultural heritage research. • Usually, only traces of the original polychromy of Greek and Roman art remain – to keep the impact to a minimum, new sampling methods for pigment provenance research are needed. • This work shows that easily available tools provide comparable (cotton swabs vs scalpel) geochemical results for pigment provenance research. Mineral pigment provenance is a promising direction in cultural heritage particularly in ancient polychromy research. The analysis of trace elements and Pb-isotopes can provide clues about the origin of pigment raw materials. While previous investigations already showed great potential for provenancing archeological-historical mineral pigments, sampling methods and reference data collections need to be developed further to evaluate the potential and limitations of this type of research. This work tests a new sampling method for pigment provenance research that collects sample material with easily available (suffused) cotton swabs for analysis by mass spectrometry. Three artifacts decorated with Egyptian blue and red pigments were selected for comparing sampling with cotton swabs to sampling with a scalpel. All three artifacts date to the 1st century BCE: The first is a colossal marble head from Lazio, Italy, which probably belonged to a seated cult statue of Zeus, and with extensive remains of ancient red paint. The two artifacts (a slag and a fragment of a terracotta vessel) were recovered during Petrie's excavations of an Egyptian blue production facility in Memphis, Egypt. The new results are consistent with previous studies, which provides the necessary quality control for the cotton swab sampling method. This work contributes to improving sampling methods for pigment provenance analysis as well as to a better understanding of past pigment production and trade networks. [ABSTRACT FROM AUTHOR]

This research delves into ancient pigment practices among the Goya‐Malabrigo societies in the Upper Delta of the Paraná River during the Late Holocene. Utilising Raman microspectroscopy and X‐ray diffraction, we analysed 33 samples from six archaeological sites and four natural outcrops. Our discoveries uncovered hematite in red pigments across diverse materials (potsherds, shells, human bones, and sediments), anatase adorning ceramics with whitish tones, and charcoal creating darker shades. These findings not only contribute to the understanding of the mineral composition of ancient colours used by Indigenous people in domestic and funerary contexts but also set the first stage for forthcoming provenance research, integrating multiple archaeometric techniques to unravel the origins of these compelling pigments. [ABSTRACT FROM AUTHOR]

This study focuses on the material characterisation of a collection of 19th-century watercolour replicas that reproduce ancient Egyptian mural paintings and illuminated decorations from medieval manuscripts. Non-contact analyses, including macro-X-ray fluorescence (MA-XRF), X-ray diffraction (XRD), and fibre-optic reflectance spectroscopy (FORS), were employed to examine the composition of the painting materials, particularly the pigments. The findings are contextualised through archival research into 19th-century technical sources on historical painting and illuminating practices, as well as contemporaneous pigment catalogues that reported commercial prices. Ultimately, this research aimed to explore whether 19th-century artists engaged with historical material practices beyond mere visual representation in their depictions of historical subjects. The results obtained from the replicas of medieval illuminations are groundbreaking, as they challenge prevailing scholarly assumptions. Notably, the use of pigments such as minium and ultramarine blue, which were held in high regard during the Middle Ages, along with the use of chalk in the preparation of the support, suggest that, in an industrialised world where engagement with material culture was increasingly driven by commercial profit, some academic circles still sought to explore and preserve selected historical material practices in the art of painting. [ABSTRACT FROM AUTHOR]

The dinoflagellate genus Karlodinium J. Larsen is well known to form harmful algal blooms (HABs), some of which can produce karlotoxins or other ichthyotoxins and thus cause fish-killing events. Among the 16 currently accepted species of Karlodinium (about half of which are reported to be toxic), six species (K. australe, K. decipiens, K. digitatum, K. elegans, K. veneficum, and K. zhouanum) have been reported or described in the coastal waters of China. However, a fine morphological and molecular characterization of the seldom-observed species K. decipiens has not been conducted; moreover, the negative effects of this species on aquatic animals have not been investigated. This work reports the morphological and phylogenetic characterization of a strain of K. decipiens isolated from Jiaozhou Bay, China, in 2019. The characterization of the strain was conducted using light and scanning electron microscopy, LSU, SSU rDNA, and ITS sequences-based systematic analyses, pigment analysis, and a detailed investigation of its potential toxic/harmful activity on aquatic animals. We observed the typical diagnostic features of K. decipiens, including its relatively large size, ellipsoidal or ovoid cell shape, ventral pore, ventral ridge connecting the two displaced ends of the cingulum, cingulum with a displacement of about one-third of the cell length, numerous polyhedral or slightly elongated chloroplasts distributed peripherally, and large nucleus located centrally. However, we also observed a large amphiesmal vesicle at the dorsal end of the ASC at the dorsal epicone, which is a novel feature that has never been reported from any species of the genus. Based on the results of this study, it is not clear whether this feature is a specific structure of the species or a common characteristic of the genus; therefore, this novel feature is worthy of further examination. Fucoxanthin was the most abundant pigment among all the carotenoids detected. The phylogenies inferred using Bayesian inference (BI) and maximum likelihood (ML) techniques confirmed the conspecificity of our isolate with the holotype K. decipiens (accession no. EF469236). In molecular trees, K. decipiens and K. antarcticum form a separate clade from other species of Karlodinium, and it should be examined whether a large amphiesma vesicle may be a characteristic of this clade. The exposure bioassays using brine shrimp (Artemia salina) indicated that K. decipiens exhibited toxicity to zooplankton, with 100% and 68% mortality observed in brine shrimp using live cell cultures and cell culture lysates over 120 h, respectively. Our work provides a detailed morphological and molecular characterization of K. decipiens from China. The results of this study broaden the known geographical distribution of this species and demonstrate it to be a harmful dinoflagellate. [ABSTRACT FROM AUTHOR]

This study focuses on the material characterisation of a collection of 19th-century watercolour replicas that reproduce ancient Egyptian mural paintings and illuminated decorations from medieval manuscripts. Non-contact analyses, including macro-X-ray fluorescence (MA-XRF), X-ray diffraction (XRD), and fibre-optic reflectance spectroscopy (FORS), were employed to examine the composition of the painting materials, particularly the pigments. The findings are contextualised through archival research into 19th-century technical sources on historical painting and illuminating practices, as well as contemporaneous pigment catalogues that reported commercial prices. Ultimately, this research aimed to explore whether 19th-century artists engaged with historical material practices beyond mere visual representation in their depictions of historical subjects. The results obtained from the replicas of medieval illuminations are groundbreaking, as they challenge prevailing scholarly assumptions. Notably, the use of pigments such as minium and ultramarine blue, which were held in high regard during the Middle Ages, along with the use of chalk in the preparation of the support, suggest that, in an industrialised world where engagement with material culture was increasingly driven by commercial profit, some academic circles still sought to explore and preserve selected historical material practices in the art of painting.

Lemna aequinoctialis (duckweed) is the smallest and fast-growing aquatic plant species producing protein-rich biomass with high protein nutritional value, phytoremediation capacity, and nutrient removal from wastewater. Duckweed may also be used as a new potential bioreactor for biological products, such as vaccines, antibodies, and pharmaceutical proteins. Based upon the potential importanc of L. aequinoctialis in phytoremediation and as a bioreactor the aim of this study was to (1) characterize the chemical and nutritional profiles of L. aequinoctialis biomass utilizing an integrated multi-trophic aquaculture system (IMTA) and a pond, and (2) investigate the cytotoxic potential of different concentrations of organic extracts and fractions using the MTT bioassay. EDXRF and ICP-MS analyses indicated the presence of trace elements in lower amounts in relation to the biomass of L. aequinoctialis in the lagoon, emphasizing the importance of plant inclusion management to reduce bioaccumulation of these elements. Analysis of mineral profiles, fatty acids, and amino acids indicated a satisfactory nutritional composition for the use of biomass as a bioproduct. Pigment analysis showed a high concentration of carotenoids, especially astaxanthin. After standardizing the controls, the MTT cell viability test was carried out utilizing rat hepatoma cell line (HTC), which are metabolizing cells that were treated with aqueous or ethanolic extracts and the dichloromethane, ethyl acetate, and methanol fractions at different concentrations. No apparent cytotoxic potential was observed following treatments, since there was no significant reduction in cell viability. Therefore, this study provides information regarding the biomass of L. aequinoctialis derived from the IMTA system, which might support further research into the application of this species as a bioproduct. [ABSTRACT FROM AUTHOR]

Macroscopic x‐ray fluorescence imaging spectroscopy (MA‐XRF) and reflectance imaging spectroscopy (RIS) are important tools in the analysis of cultural heritage objects, both for conservation and art historical research purposes. The elemental and molecular distributions provided by MA‐XRF and RIS respectively, are particularly useful for the identification and mapping of pigments in easel paintings. While MA‐XRF has relatively established data processing methods based on modeling of the underlying physics, RIS data cannot be modeled with sufficient precision and its processing has considerable room for improvements. This work seeks to improve RIS data processing workflows in the short wavelength infrared range (SWIR, 1000–2500 nm) with a novel method that fits Gaussian profiles to pigment‐specific absorption features, and we compare its performance to MA‐XRF for the task of semi‐quantitative pigment mapping, evaluating their limits of detection (LODs) and the matrix effects that affect their signals. Two pigments are considered in this work, lead white and blue verditer, which are mapped in SWIR RIS using the first overtone of OH stretching of their primary compounds, hydrocerussite (Pb3(CO3)2(OH)2) and azurite (Cu3(CO3)2(OH)2), at 1447 and 1497 nm respectively, and in MA‐XRF using the Pb‐L and Cu‐K fluorescence signals. The methods are evaluated using two sets of custom‐prepared paint samples, as well as a 16th‐century painting, discussing the identification, mapping, and semi‐quantitative analysis of the considered pigments. We found SWIR RIS to be a pigment‐specific method with a longer linear range but inferior LODs and penetration depth when compared to MA‐XRF, the latter is often not capable of discriminating between different pigments with identical elemental markers. We furthermore present a novel color scale that allows the simultaneous visualization of signals above and below a confidence limit. [ABSTRACT FROM AUTHOR]

In 1949, Almada Negreiros painted at the maritime station of Rocha do Conde de Óbidos, in Lisbon, six monumental mural paintings, which are considered as his highest artistic achievement. On these paintings, he resorted to a bright colourful palette, which needs to be studied to support conservation and preservation of these artworks for future generations. Among the pigments under study within project ALMADA, the identification of the green samples is the most challenging, as Almada Negreiros seems to have explored different hues by using simultaneously inorganic (e.g., emerald green, Scheele's green and viridian) as well as organo‐synthetic pigments that were rather unusual when employing a traditional mural painting technique (e.g., PG7 and PG8). Moreover, he seems to have admixed white (e.g., titanium white) or blue pigments (e.g., ultramarine) to modify the hues. The different colourants found, as well as the use of mixtures of pigments, hints that Almada Negreiros was keen on experimenting and applying relatively novel painting materials. Raman spectroscopy, given its ability to identify inorganic as well as organic components, is a key analytical tool to discriminate between all these compounds. The findings were also supported by complimentary analytical techniques, including colourimetry, handheld X‐ray fluorescence spectroscopy (h‐XRF) and micro‐Fourier‐transform infrared spectroscopy (μ‐FT‐IR). Identification of the green pigments by Raman spectroscopy is, however, not always straightforward, and it is demonstrated how changes in relative band intensities and band broadening can point to mixtures, where the Raman spectral features of some compounds can easily be overseen in the spectrum. [ABSTRACT FROM AUTHOR]

Simple Summary: The Pearl River Estuary (PRE) in China, a highly urbanized coastal area, presents a unique opportunity to study the effects of environmental changes on the phytoplankton com-munity. In September 2018, a field study was conducted to examine how the photosynthetic status and spatial distribution of these organisms varied from freshwater to oceanic waters. Dinophyta and Haptophyta were prevalent in seawater, while Chlorophyta and Cryptophyta dominated from freshwater to estuarine water. Bacillariophyta were found across all regions. Phytoplankton in the mixing zone showed signs of stress due to fluctuating environmental conditions, whereas those in freshwater and oceanic areas appeared more photosynthetically active. Human activities have in-creased nutrient levels in the estuary, leading to higher chlorophyll concentrations and more diverse phytoplankton communities upstream. Understanding these patterns helps us assess the health of coastal ecosystems, which is crucial for managing the impacts of climate change and human development on marine environments. The Pearl River Estuary (PRE) is one of the world's most urbanized subtropical coastal systems. It presents a typical environmental gradient suitable for studying estuarine phytoplankton communities' dynamics and photosynthetic physiology. In September 2018, the maximum photochemical quantum yield (Fv/Fm) of phytoplankton in different salinity habitats of PRE (oceanic, estuarine, and freshwater zones) was studied, revealing a complex correlation with the environment. Fv/Fm of phytoplankton ranged from 0.16 to 0.45, with taxa in the upper Lingdingyang found to be more stressed. Community composition and structure were analyzed using 18S rRNA, accompanied by a pigment analysis utilized as a supplementary method. Nonmetric multidimensional scaling analysis indicated differences in the phytoplankton spatial distribution along the estuarine gradients. Specificity-occupancy plots identified different specialist taxa for each salinity habitat. Dinophyta and Haptophyta were the predominant taxa in oceanic areas, while Chlorophyta and Cryptophyta dominated freshwater. Bacillariophyta prevailed across all salinity gradients. Canonical correlation analysis and Mantel tests revealed that temperature, salinity, and elevated nutrient levels (i.e., NO3−-N, PO43−-P, and SiO32−-Si) associated with anthropogenic activities significantly influenced the heterogeneity of community structure. The spatial distribution of phytoplankton, along with in situ photosynthetic characteristics, serves as a foundational basis to access estuarine primary productivity, as well as community function and ecosystem health. [ABSTRACT FROM AUTHOR]

The marine phytoplankton community responds to latitudinal, longitudinal (coast to ocean), and vertical environmental gradients, an important subject in Oxygen minimum zones (OMZ). The phytoplankton structure and the effect of environmental gradients along the central Mexican Pacific, an area within an OMZ, were studied, especially the importance of size fractions and taxonomic groups. A combination of various methods and protocols, such as microscopic analysis, flow cytometer, and pigment analysis, were followed in this study. Oceanographic conditions included thermal gradients along the study area and unreported evidence of a weak upwelling in the southern zone (Acapulco). Vertical distribution of chlorophyll a showed subsurface maxima (SCM, 15-45 m depth) in all stations, and deeper chlorophyll-a maxima (DCM, 85-95 m depth) in more oceanic stations. Chain-forming diatoms dominated in the northern zone stations. Prochlorococcus, Synechococcus, and picoeukaryotes abundances ranged between 0.01 to 21.7 cells×104 mL-1, although most samples showed the highest contribution to biomass (47.95 µg C L-1) by picoeukaryotes. Expected tendencies of Prochlorococcus distribution were observed: highest densities coincided with the DCM and divinyl chlorophyll-a distribution at oceanic stations. Fucoxanthin had the highest concentrations, whereas fucoxanthin and zeaxanthin concentrations were higher at SCM depths. We documented the co-dominance of the pico- and microplankton: picoplankton was important at the DCM, related to oligotrophic and more stratified water column, whereas microplankton prevailed in coastal stations, with mixed water column, high nutrient concentrations, and diatoms as the dominant group. Picoeukaryotes abundances were related to the concentration of prasinoxanthin, which suggests an important mamiellophyte component not previously revealed. [ABSTRACT FROM AUTHOR]

• Discovering the palette of the 20th century Chinese artist Wu Guanzhong. • Integrated use of MA-XRF, HSI and Raman spectroscopy for pigment analysis. • Automated assisted pigment analysis workflow with machine learning. • Processing multiple HSI datasets within one UMAP model. A paint palette of the 20th-century Chinese modern artist Wu Guanzhong (1919–2010) was studied with an integrated spectroscopic approach, macro-scale non-invasive techniques hyperspectral imaging (HSI) and macro X-ray fluorescence (MA-XRF), complemented with Raman spectroscopy. The palette is revealed to be comprised of synthetic inorganic and organic pigments, typical of the 20th century modern palette that is dominated by azo and phthalocyanine pigments. HSI datasets of the paint palette and those of Wu's oil painting 'Xidi Village' (2001) were then processed within one unsupervised Uniform Manifold Approximation and Projection (UMAP) model, in an attempt to identify connections between the artefact and the artwork, so that known pigment results of the palette may provide preliminary pigment assignment for the painting. This study describes the steps taken to establish this automated assisted pigment analysis workflow, which involves processing multiple HSI datasets within one UMAP model, density clustering, non-negative least square (NNLS) fitting to extract endmembers (EM) spectra and to generate distribution maps. The approach to perform micro-sampling pigment analysis on the artist's palette (or artist's materials) is considered less invasive to the integrity than that from artworks, the results of which have demonstrated to serve as a critical resource to support further pigment analysis studies of the artist's paintings via non-invasive analytical techniques. [ABSTRACT FROM AUTHOR]

The coastal area of Qinhuangdao, particularly the Changli Gold Coast Nature Reserve, is experiencing ecological degradation and frequent Harmful Algal Blooms (HABs). This study focuses on the changing phytoplankton communities in these coastal waters, examining them from both a macroscopic and microscopic perspective. Utilizing microscopy, molecular techniques, and pigment analysis, seasonal shifts were observed, with diatoms predominating in June and July, and dinoflagellates in August. Our morphological examination enabled the classification of 89 species into four distinct groups. The species Paralia sulcata and Pseudo-nitzschia pungens were most abundant in early summer, while Tripos furca, a dinoflagellate, dominated in August. This indicates a shift in phytoplankton communities due to environmental factors such as phosphate deficiency and high nitrogen/phosphorus ratios. Additionally, the study notes the impact of reduced river runoff and reintroduction of scallop farming contributing to nitrogen-rich eutrophication in August. Molecular analysis revealed a disparity between microscopic observations and the prevalence of Teleaulax blooms during early summer. Elevated concentrations of TN and DOC, coupled with limited water exchange, emerged as primary factors contributing to their occurrence. Sediment analysis revealed a high diversity but low abundance of dinoflagellates in August, with a significant presence of harmful species. The study highlights the shift from diatoms to harmful dinoflagellate populations, exacerbated by eutrophication and pollution, leading to HABs. These findings provide a theoretical basis for understanding toxic algal blooms and are crucial for environmental agencies in developing strategies to protect and sustainably develop offshore environments. [ABSTRACT FROM AUTHOR]

The conservation of Cultural Heritage in cave environments, especially those hosting cave art, requires comprehensive conservation strategies to mitigate degradation risks derived from climatic influences and human activities. This study, focused on the Polychrome Hall of the Cave of Altamira, highlights the importance of integrating remote sensing methodologies to carry out effective conservation actions. By coupling a georeferenced Ground Penetrating Radar (GPR) with a 1.6 GHz central-frequency antenna along with photogrammetry, we conducted non-invasive and high-resolution 3D studies to map preferential moisture pathways from the surface of the ceiling to the first 50 cm internally of the limestone structure. In parallel, we monitored the dynamics of surface water on the Ceiling and its correlation with pigment and other substance migrations. By standardizing our methodology, we aim to increase knowledge about the dynamics of infiltration water, which will enhance our understanding of the deterioration processes affecting cave paintings related to infiltration water. This will enable us to improve conservation strategies, suggesting possible indirect measures to reverse active deterioration processes. Integrating remote sensing techniques with geospatial analysis will aid in the validation and calibration of collected data, allowing for stronger interpretations of subsurface structures and conditions. All of this puts us in a position to contribute to the development of effective conservation methodologies, reduce alteration risks, and promote sustainable development practices, thus emphasizing the importance of remote sensing in safeguarding Cultural Heritage. [ABSTRACT FROM AUTHOR]

While edible algae might seem low in fat, the lipids they contain are crucial for good health and preventing chronic diseases. This study introduces a binary matrix to analyze all the polar lipids in both macroalgae (Wakame—Undaria pinnatifida, Dulse—Palmaria palmata, and Nori—Porphyra spp.) and microalgae (Spirulina—Arthrospira platensis, and Chlorella—Chlorella vulgaris) using matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). The key lies in a new dual matrix made by combining equimolar amounts of 1,5-diaminonaphthalene (DAN) and 9-aminoacridine (9AA). This combination solves the limitations of single matrices: 9AA is suitable for sulfur-containing lipids and acidic phospholipids, while DAN excels as an electron-transfer secondary reaction matrix for intact chlorophylls and their derivatives. By employing the equimolar binary matrix, a wider range of algal lipids, including free fatty acids, phospholipids, glycolipids, pigments, and even rare arsenosugarphospholipids were successfully detected, overcoming drawbacks related to ion suppression from readily ionizable lipids. The resulting mass spectra exhibited a good signal-to-noise ratio at a lower laser fluence and minimized background noise. This improvement stems from the binary matrix's ability to mitigate in-source decay effects, a phenomenon often encountered for certain matrices. Consequently, the data obtained are more reliable, facilitating a faster and more comprehensive exploration of algal lipidomes using high-throughput MALDI-MS/MS analysis. [ABSTRACT FROM AUTHOR]

Background: Pigment Red 53 is a dangerous synthetic dye that is often added to cosmetics, even though its use in cosmetic products has been prohibited because of possible impacts on health. Faster and more sensitive detection of Pigment Red 53 is needed for onsite analysis to protect the community from illegal cosmetics that contain the dye. Indicator color charts are a kind of analytical method that can be used to detect Pigment Red 53 in cosmetic products, including lipstick, rouge, and eyeshadow. Such charts are practical, fast, and can be used for onsite analysis. Methods: In this study, an indicator for Pigment Red 53 detection was obtained through a reagent reaction that caused a specific color change. An indicator color chart was then produced by setting out in paper form the series of colors which resulted from the reaction of specific chemical reagents and Pigment Red 53 solutions at concentrations of 10, 20, 40, 60, 80, and 100 ppm. Results: The testing results showed that the indicator color chart may be used as an initial screening method for the detection of Pigment Red 53 in cosmetic products with a detectable minimum concentration of 10 ppm. Out of nine samples, only one (Eyeshadow 3) tested positive for Pigment Red 53. Further analysis was carried out on the indicator color chart and the results showed good agreement with TLC and UV–Vis spectrophotometry methods. Conclusion: The results reported in this paper demonstrate that the indicator color chart is a good prospective method for onsite analysis to detect Pigment Red 53 in cosmetic samples, with a lower detection limit compared to polymer‐based indicators. [ABSTRACT FROM AUTHOR]

The diverse and changing pigmentation of the skin allows fish to adapt to environmental conditions for survival and communication with conspecifics. However, various physical and chemical environmental factors, including pollutants, affect fish coloration. Therefore, the implementation of an analysis of skin pigmentation has been considered in fish well-being and ecotoxicological studies. A physiological color change is achieved by the motility of melanincontaining organelles: they aggregate into the perikaryon or disperse throughout the cytoplasm of melanophores in response to various stimuli. In our study, we addressed the issue of implementing the analysis of pigment dispersion in melanophores in stickleback skin to assess the response of fish to oxidative stress. We examined pigment dispersion in day and night skin samples collected from the dorsal, lateral and ventral regions. The degree of pigment dispersion we assessed by the melanophore index. The total number of melanophores counted in the defined skin area was significantly higher in the night samples than in the day samples. Only in day samples of dorsal skinwe observed the significant changes in pigment dispersion after exposure to stress: melanin was predominantly in the aggregated state. In the night samples, we did not report any response to stress in any part of the skin. Examination of pigment dispersion in melanophores in stickleback skin can be useful for assessing the welfare of fish and detecting toxic agents in the environment, but under specified conditions: in sticklebacks, it is analysis of dorsal skin during the day. [ABSTRACT FROM AUTHOR]

Southern Ocean phytoplankton form the base of the Antarctic food web, influencing higher trophic levels through biomass and community structure. We examined phytoplankton distribution and abundance in the Indian Sector of the Southern Ocean during austral summer as part a multidisciplinary ecosystem survey: Trends in Euphausiids off Mawson, Predators and Oceanography (TEMPO, 2021). Sampling covered six meridional transects from 55-80°E, and from 62°S or 63°S to the ice edge. To determine phytoplankton groups, CHEMTAX analysis was undertaken on pigments measured using HPLC. Diatoms were the dominant component of phytoplankton communities, explaining 56% of variation in chlorophyll a (Chl a), with haptophytes also being a major component. Prior to sampling the sea ice had retreated in a south-westerly direction, leading to shorter ice-free periods in the west (< 44 days, ≤65°E) compared to east (> 44 days, ≥70°E), inducing a strong seasonal effect. The east was nutrient limited, indicated by low-iron forms of haptophytes, and higher silicate:nitrate drawdown ratios (5.1 east vs 4.3 west), pheophytin a (phaeo) concentrations (30.0 vs 18.4 mg m-2) and phaeo:Chl a ratios (1.06 vs 0.53). Biological influences were evident at northern stations between 75-80°E, where krill “super-swarms” and feeding whales were observed. Here, diatoms were depleted from surface waters likely due to krill grazing, as indicated by high phaeo:Chl a ratios (> 0.75), and continued presence of haptophytes, associated with inefficient filtering or selective grazing by krill. Oceanographic influences included deeper mixed layers reducing diatom biomass, and a bloom to the north of the southern Antarctic Circumpolar Current Front in the western survey area thought to be sinking as waters flowed from west to east. Haptophytes were influenced by the Antarctic Slope Front with high-iron forms prevalent to the south only, showing limited iron transfer from coastal waters. Cryptophytes were associated with meltwater, and greens (chlorophytes + prasinophytes) were prevalent below the mixed layer. The interplay of seasonal, biological and oceanographic influences on phytoplankton populations during TEMPO had parallels with processes observed in the BROKE and BROKE-West voyages conducted 25 and 15 years earlier, respectively. Our research consolidates understanding of the krill ecosystem to ensure sustainable management in East Antarctic waters.

Purple paprika (Capsicum annuum) is a vegetable with potential economic value; however, enhancing and maintaining the purple fruit color is challenging. We investigated the effects of night blue-light supplementation on fruit growth, anthocyanin content, and gene expression in purple paprika. During two duplicated experiments conducted in spring and autumn, purple paprika plants were subjected to blue-light supplementation at night. Ten days after fruits were pollinated, night blue light with photosynthetic photon flux density (PPFD) of 80 to 100 µmol·s−1·m−2 was supplied from 1800 HR to 0500 HR (11 hours). Fruit samples were harvested 15, 20, and 40 days after pollination from control (no-light treatment) and blue light–treated fruits. The fruit size, fresh weight, anthocyanin content, and expression levels of anthocyanin biosynthesis-related genes (HY5, bHLH, WDR, MYB, PAL, CHS, F3H, DFR, ANS, and UFGT) were determined. Blue-light supplementation increased the anthocyanin-related gene expressions in the fruit peel, enhancing anthocyanin synthesis and accumulation. However, there were no significant differences between the growth of control and blue light–treated fruits. These findings highlight the potential of night blue-light supplementation to enhance anthocyanin content in purple paprika fruits without affecting overall fruit growth.

Morchella sextelata, a highly sought-after edible mushroom worldwide, is evaluated based on its cap color as an essential commercial property indicator. In the present study, the effects of blue light on cap pigmentation in M. sextelata, as well as the synthesis and structural characteristics of melanin pigments within the cap were examined. The results showed that an increase in the proportion of blue light within the lighting environment promoted melanin synthesis and melanization of the cap. Transmission and scanning electron microscopy revealed the localization of melanin within the mycelium and its ultrastructural characteristics. The UV-visible analysis demonstrated that melanin exhibited a maximum absorption peak at 220 nm and possessed high alkaline solubility as well as acid precipitability. The structural characteristics of melanin were analyzed using FTIR, NMR, HPLC, and elemental analysis, which confirmed the presence of eumelanin, pheomelanin, and allomelanin in both brown and black caps. Furthermore, blue light can stimulate the synthesis of both eumelanin and pheomelanin. The obtained results can serve as the foundation for comprehending the mechanism by which light regulates color formation in mushrooms. [ABSTRACT FROM AUTHOR]

Fungal species in the Nectriaceae, such as Fusarium spp. (Hypocreales: Nectriaceae), are etiologic agents of hyalohyphomycosis capable of producing violaceous or yellowish pigments under certain conditions, while Curvularia spp. (Pleosporales: Pleosporaceae) are agents of phaeohyphomycosis and typically produce melanin in their cell walls. In nectriaceous and pleosporaceous fungi, these pigments are mainly constituted by polyketides (e.g., azaphilones, naphthoquinones, and hydroxyanthraquinones). Considering the importance of pigments synthesized by these genera, this work focused on the selective extraction of pigments produced by eight Fusarium solani species complex and one Curvularia verruculosa isolate recovered from dermatomycosis specimens, their separation, purification, and posterior chemical analysis. The pigments were characterized through spectral and acid–base analysis, and their maximum production time was determined. Moreover, spectral identification of isolates was carried out to approach the taxonomic specificity of pigment production. Herein we describe the isolation and characterization of three acidic pigments, yellowish and pinkish azaphilones (i.e., coaherin A and sclerotiorin), and a purplish xanthone, reported for the first time in the Nectriaceae and Pleosporaceae, which appear to be synthesized in a species-independent manner, in the case of fusaria. [ABSTRACT FROM AUTHOR]

Anoectochilus roxburghii (Wall.) Lindl is a perennial herb of the Orchidaceae family; a yellow–green mutant and a yellow mutant were obtained from the wild type, thereby providing good material for the study of leaf color variation. Pigment content analysis revealed that chlorophyll, carotenoids, and anthocyanin were lower in the yellow–green and yellow mutants than in the wild type. Transcriptome analysis of the yellow mutant and wild type revealed that 78,712 unigenes were obtained, and 599 differentially expressed genes (120 upregulated and 479 downregulated) were identified. Using the Kyoto Encyclopedia of Genes and Genomes pathway analysis, candidate genes involved in the anthocyanin biosynthetic pathway (five unigenes) and the chlorophyll metabolic pathway (two unigenes) were identified. Meanwhile, the low expression of the chlorophyll and anthocyanin biosynthetic genes resulted in the absence of chlorophylls and anthocyanins in the yellow mutant. This study provides a basis for similar research in other closely related species. [ABSTRACT FROM AUTHOR]

Camellia nitidissima is famous for its golden flowers. Its flowers are rich in secondary metabolites, and they have ornamental, medicinal, and edible value. Pigment composition and regulation has been studied in the golden petals, but there has been little research on pigment composition or the molecular mechanism underlying yellow stamens in C. nitidissima. To explore the molecular mechanism of yellow stamen formation, three developmental stages (S0, S1, and S2) were used for transcriptome and pigment analyses. Pigment analysis showed that the flavonoid content increased sharply from the S0 to S1 stage and decreased from the S1 to S2 stage, and the carotenoid content increased sharply during yellow stamen formation (from the S1 to S2 stage). RNA-seq analysis showed that a total of 20,483 differentially expressed genes (DEGs) were identified. KEGG and heatmap analyses showed that flavonoid and carotenoid biosynthesis pathways were enriched, and we identified 14 structural genes involved in flavonoid biosynthesis and 13 genes involved in carotenoid biosynthesis and degradation. In addition, the expression of carotenoid- and flavonoid-related genes was consistent with carotenoid and flavonoid content. In addition, correlation network analysis indicated that the WARYK, MYB, bHLH, and AP2/ERF transcription factor families were screened for involvement in the biosynthesis of flavonoids and carotenoids. In this study, we describe the pathway associated with color formation in the stamens of C. nitidissima. [ABSTRACT FROM AUTHOR]

Birds display a rainbow of eye colours, but this trait has been little studied compared with plumage coloration. Avian eye colour variation occurs at all phylogenetic scales: it can be conserved throughout whole families or vary within one species, yet the evolutionary importance of this eye colour variation is under‐studied. Here, we summarize knowledge of the causes of eye colour variation at three primary levels: mechanistic, genetic and evolutionary. Mechanistically, we show that avian iris pigments include melanin and carotenoids, which also play major roles in plumage colour, as well as purines and pteridines, which are often found as pigments in non‐avian taxa. Genetically, we survey classical breeding studies and recent genomic work on domestic birds that have identified potential 'eye colour genes', including one associated with pteridine pigmentation in pigeons. Finally, from an evolutionary standpoint, we present and discuss several hypotheses explaining the adaptive significance of eye colour variation. Many of these hypotheses suggest that bird eye colour plays an important role in intraspecific signalling, particularly as an indicator of age or mate quality, although the importance of eye colour may differ between species and few evolutionary hypotheses have been directly tested. We suggest that future studies of avian eye colour should consider all three levels, including broad‐scale iris pigment analyses across bird species, genome sequencing studies to identify loci associated with eye colour variation, and behavioural experiments and comparative phylogenetic analyses to test adaptive hypotheses. By examining these proximate and ultimate causes of eye colour variation in birds, we hope that our review will encourage future research to understand the ecological and evolutionary significance of this striking avian trait. [ABSTRACT FROM AUTHOR]

Objective/Background: Camellia L., belonging to the Theaceae family, is a diverse group of plant species native to various regions of Asia. Methods: Chlorophyll and carotenoid contents in leaves of three Camellia species, namely Camellia quephongensis, Camellia yokdonensis, and Camellia longii, were determined using a spectrophotometric method. Phenolic compounds of the leaf extracts were quantified using high-performance liquid chromatography. Additionally, antioxidant activity, anti-α-amylase and in vitro antiinflammatory properties of the extracts were evaluated. Results: The total carotenoid content in C. longii was the highest, whereas the total chlorophyll content in this species was the lowest. Most of the phenolic compounds in C. quephongensis were found at the greatest concentrations compared to the other species. The extract from C. quephongensis exhibited the strongest antioxidant properties estimated by ABTS and DPPH free radical scavenging assays. This activity was shown to be comparable with that of ascorbic acid. All the Camellia extracts may possess a much less potent anti-α-amylase activity in comparison with acarbose. They could also be weaker than diclofenac with respect to in vitro anti-inflammatory activity evaluated by albumin denaturation inhibition assay. Conclusions: The findings of this investigation provide the initial insights into pigments and phenolics present in the various Camellia species and pave the way for the development of functional foods that could potentially offer a range of health benefits. [ABSTRACT FROM AUTHOR]

Delving into the past through the study of pottery, this research employs scientific techniques to explore Jiangzhai pottery from circa 3000–4000 BCE. The investigation revealed that the red and grey pottery, despite their color differences, have similar elemental compositions, suggesting that these variations are not due to elemental differences but likely due to a higher concentration of Fe3+ in the red pottery. Analysis of the pigments using elemental analysis, polarized light microscopy, and XRD showed that the red pigment contains ochre, the black is a mix of pyrolusite and magnetite, and the white is composed of calcite. Additionally, thermal expansion analysis determined that the firing temperature of Jiangzhai colored pottery is around 1050 °C, with similar temperatures for both red and grey pottery, suggesting that kiln operations like stacking or overlapping are likely causes of the color variations. This study not only broadens our understanding of ancient pottery-making techniques and cultural practices but also emphasizes the critical role of scientific analysis in preserving and interpreting the rich artistic and technological legacy of ancient cultures. [ABSTRACT FROM AUTHOR]

The study was focused on evaluating the short-term irrigation effect of three different types of distillery wastewater, i.e., untreated, primary treated, and secondary treated, on the germination, growth, photosynthetic pigments, and antioxidant enzymes of pea (Pisum sativum L. var. Rachna). The findings indicated that exposure to 50% secondary treated distillery wastewater (ST50) resulted in the maximum values for positive germination parameters of pea, including germination percentage, germination value, germination index, peak value, vigor index, speed of germination, and tolerance index. The minimum values were observed at 100% concentration of untreated wastewater (UT100). In contrast, the maximum values for various negative germination parameters, i.e., percent inhibition, seedling mortality, and germination period, were observed at UT100 and minimum at ST50. All the growth parameters studied, i.e., length of shoot, length of root and length of seedlings, fresh weight of shoot, fresh weight of root, dry weight of shoot, and dry weight of root, showed maximum values at ST50 and minimum at UT100. Photosynthetic pigment analysis also followed a similar trend. The antioxidative enzyme characterization of Pisum sativum L. var. Rachna revealed the minimum values of catalase, ascorbic peroxidase, glutathione reductase, and superoxide dismutase at ST25 (25% concentration of secondary treated distillery wastewater) and maximum values were observed at UT100. [ABSTRACT FROM AUTHOR]

The historical impacts of eutrophication processes were investigated in six subtropical reservoirs (São Paulo, Brazil) using a paleolimnological approach. We questioned whether the levels of pigment indicators of algal biomass could provide information about trophic increase and whether carotenoid pigments could offer additional insights. The following proxies were employed: organic matter, total phosphorus, total nitrogen, photosynthetic pigments (by high-performance liquid chromatography), sedimentation rates, and geochronology (by 210 Pb technique). Principal component analysis indicated a gradient of eutrophication. In eutrophic reservoirs (e.g., Rio Grande and Salto Grande), levels of lutein and zeaxanthin increased over time, suggesting growth of Chlorophyta and Cyanobacteria. These pigments were significantly associated with algal biomass, reflecting their participation in phytoplankton composition. In mesotrophic reservoirs, Broa and Itupararanga, increases and significative linear correlations (r > 0.70) between pigments and nutrients are mainly linked to agricultural and urban activities. In the oligotrophic reservoir Igaratá, lower pigment and nutrient levels reflected lesser human impact and good water quality. This study underscores eutrophication's complexity across subtropical reservoirs. Photosynthetic pigments associated with specific algal groups were informative, especially when correlated with nutrient data. The trophic increase, notably in the 1990s, may have been influenced by neoliberal policies. Integrated pigment and geochemical analysis offers a more precise understanding of eutrophication changes and their ties to human factors. Such research can aid environmental monitoring and sustainable policy development. [ABSTRACT FROM AUTHOR]

This paper presents the use of X-ray computed tomography and X-ray fluorescence in the analysis and expert research of the seventeenth century printed book "Eukhologīon albo Molitoslov, ili Trebnik" from Kiev. The main purpose of the survey was to confirm whether the book binding is original or whether it is a rebinding, and whether there are any fragments of the hidden older texts. Commonly used radiography is usually not able to provide sufficient information for these purposes. On the other hand, computed tomography allows a detailed and three-dimensional documentation of the bookbinding technology and the structure of the materials used, including the wooden boards. It will be presented that all elements of the weave are clearly visible, making it possible to show that there are no internal defects in the stitching and materials. It has also been convincingly shown that there are no fragments or layers of older texts in the binding, so no further invasive intervention will be necessary regarding this aspect. The paper also demonstrates the possibility of reading the text in a closed book utilising X-ray computed tomography data; this option may be advantageous for massively damaged manuscripts. It will also be shown, that thanks to detailed tomographic imaging of the wood structure of the boards, a dendrochronological survey can be successfully carried out without invasive intervention into their outer layers. From the CT data it was also found that the pigments of the letters have significantly different densities. Therefore, as part of the survey, elemental analysis of the writing was also carried out using a portable X-ray fluorescence spectrometer to confirm and clarify this finding. [ABSTRACT FROM AUTHOR]

The Yungang Grottoes, excavated during the 5th to 6th centuries AD, stand as a pinnacle of Buddhist sculpture, representing a precious world cultural heritage. Since their excavation, the grottoes have undergone multiple phases of painting, with a significant amount of pigment still present on the surfaces of the stone carvings. Since the 1990s, two large-scale archaeological excavations have been conducted on both the front ground and the summit of Yungang Grottoes. During these excavations, various artifacts with accompanying pigments were unearthed, encompassing stone carvings, grinding tools, architectural components, fragments of murals, and remnants of clay sculptures, spanning the historical periods of the Northern Wei, Liao-Jin, and Ming-Qing dynasties. Using portable X-ray fluorescence spectrometry, portable microscopy, polarizing microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, and confocal Raman microscopy, we conducted a comprehensive analysis of these painted elements. The investigation revealed the presence of hematite, vermilion, goethite, malachite, calcium carbonate, lead white, and ivory black pigments in the Northern Wei samples. The Liao-Jin samples exhibited hematite, while the Ming-Qing samples contained vermilion, minium, atacamite, lead white, and Prussian blue. [ABSTRACT FROM AUTHOR]

Tidal freshwater zones (TFZs) can significantly affect nutrient transport from watersheds to estuaries through biogeochemical cycling. Phytoplankton, pivotal in nutrient cycling, have been relatively understudied within TFZs. Employing accessory pigment analysis, this study assessed the contribution of diverse phytoplankton groups to chlorophyll a (chl a) biomass over an annual cycle under baseflow conditions. Spatial and temporal patterns in chl a concentrations and community structure as inferred from accessory pigment analysis were evaluated in relation to temperature, dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP), and DIN/SRP ratios. Downstream phytoplankton transport and seasonal succession within the TFZ, driven by nutrient levels and temperature, lead to variations in chl a concentration and community composition. Overall chl a levels were higher in the TFZ than in the upstream river and downstream estuary, with cyanobacteria prominently contributing to chl a biomass, especially in the lower TFZ sections. This study underscores the role of prolonged residence times and nutrient enrichment in TFZs, resulting in elevated chl a concentrations and shaping phytoplankton community composition, with implications for downstream estuaries. [ABSTRACT FROM AUTHOR]

Introduction: We conducted a cross-sectional study to compare macular pigment optical density (MPOD) in eyes with idiopathic macular holes with bumpy (bbMH) and smooth borders (sbMH) and to assess the relation between MPOD and optical coherence tomography findings. Thirty eyes from thirty patients affected by idiopathic macular hole were studied. Methods: All patients underwent SD-OCT and macular pigment optical density (MPOD) analysis. Comparison between the two border phenotypes were estimated at baseline, as well as the differences in MPOD, minimum and basal hole diameter, tractional hole index (THI), macular hole index (MHI), diameter hole index (DHI), and ELM integrity metrics between the two groups. Results: The mean MPOD was 0.09 ± 0.08 in bbMHs and 0.16 ± 0.11 in sbMHs (p = 0.010). Correlation analysis between MPOD and minimum hole diameter revealed a negative association (rho = − 0.707, p = 0.008) in bbMH and a positive association (rho = 0.702, p = 0.019) in sbMH. MPOD and basal diameter were negatively correlated in bbMH (rho = − 0.77, p = 0.001) and positively correlated in sbMH (rho = 0.675, p = 0.019). Indeed, MPOD is negatively correlated with THI and MHI in sbMH (rho = − 0.684 p = 0.019; rho = − 0.665 p = 0.019, respectively) and positively correlated in bbMH (rho = 0.593 p = 0.037; rho = 0.658 p = 0.018, respectively). Conclusions: MPOD is significantly reduced in bbMHs compared to sbMHs. The two border phenotypes also differ for tractional and tangential indexes, possibly reflecting a different pathogenesis. Further studies are needed to understand the prognostic role of MPOD. [ABSTRACT FROM AUTHOR]

Introduction: Violacein, a bis-indole produced by various bacteria is known to display extensive pharmaceutical properties. Unfortunately, low productivities in natural violacein producers have led to inconsistent violacein supply, limiting its application as future therapeutics. Heterologous expression systems such as Escherichia coli and Pichia pastoris offers an alternative means of producing these high-valued secondary metabolites. This work describes the development of a genetic system for violacein heterologous production in E. coli. Methods: A violacein producer, C. violaceum, MTH01, was isolated from the limnological grounds of Universiti Sains Malaysia, Penang. Using gene specific primers, the entire 7.3 kb violacein gene cluster was successfully amplified from C. violaceum MTH01 DNA, cloned into pUC19 vector (pVio19) and then subcloned into pET-3a and pET-11b, yielding recombinant vectors, pVio3a and pVio11b, respectively. For heterologous expression, parameters such as carbon sources, temperature, inducer (IPTG) and L-tryptophan were optimised. Violacein extracted from purple-pigmented E. coli transformants were analysed using TLC and FTIR. Results: After a few days, E. coli transformants containing either pVio3a or pVio11b developed purple colonies, indicating that violacein was successfully expressed in E. coli. TLC analysis of the pigment extract revealed Rf values comparable to deoxyviolacein, an intermediary metabolite in violacein biosynthesis, while FTIR spectra revealed the presence of amine and carbonyl groups, both of which are characteristics of an indole. Conclusion: The E. coli heterologous system described here could utilize either glucose or glycerol as carbon source. Addition of L-tryptophan to growth medium was necessary for successful expression of the violacein pathway. [ABSTRACT FROM AUTHOR]

Zygnematophyceae, a class of freshwater green algae, exhibit distinctive seasonal dynamics. The increasing frequency of cold snaps during the growing season might challenge the persistence of some populations. The present study explored the frost hardiness of two Mougeotia species isolated from different elevations and habitats. Additionally, a phylogenetic (rbcL sequence), ultrastructural and physiological characterization was performed. Both species, grown under standard culture conditions and cold acclimated cultures (+4°C), were exposed to freezing temperatures down to −9°C. Furthermore, ultrastructural‐, hydrogen peroxide (H2O2)‐ and photosynthetic pigment analysis were performed on cells exposed to −2°C, with and without induced ice nucleation. The alpine M. disjuncta showed a higher frost hardiness (LT50 = −5.8°C), whereas the lowland M. scalaris was susceptible to ice. However, frost hardiness did not improve after cold acclimation in either species but rather decreased significantly in M. disjuncta (LT50 = −4.7°C). Despite darkness, prolonged sub‐zero temperatures or freezing induced the activation of the xanthophyll (VAZ) cycle in M. scalaris. Our results demonstrate that frost hardiness varies within the genus Mougeotia and that the VAZ cycle can be activated in the dark under subzero temperature‐ and freezing stress but does not necessarily increase frost hardiness. As highly frost hardy cell types are usually formed at the end of the growing season, the ability of young cells to survive ice formation in the upper subzero temperature range represents a crucial survival strategy in populations exposed to late spring frosts. [ABSTRACT FROM AUTHOR]

This contribution presents the results of a technical investigation on the pigments of William Burges' Great Bookcase (1859–62), preserved at the Ashmolean Museum. It is the first thorough material investigation of a remarkable piece of Gothic Revival painted furniture, notably an artwork by Burges, whose work has so far received little attention from a technical point of view. This study was developed during the Covid-19 pandemic, which significantly affected the planned research activities since the investigation relied extensively on collaborations with institutions within and beyond the University of Oxford. The disruption caused by the lockdown and other restrictions went far beyond any prediction and led us to redefine the project's outcome and methodology 'on the fly' while maintaining its overall vision. However, thanks to the timeliness of a substantial research grant received from the Capability for Collection Fund (CapCo, Art and Humanities Research Council), we could ultimately turn this research into a unique opportunity to test the potential of recently acquired instruments, namely the Opus Apollo infrared camera and the Bruker CRONO XRF mapping spectrometer. Therefore, besides reporting on the findings, this contribution outlines the strategy adopted and assesses the new equipment's capability for the non-invasive analysis of complex polychromies. [ABSTRACT FROM AUTHOR]

Although most cyanobacteria use visible light (VL; λ = 400–700 nm) for photosynthesis, some have evolved strategies to use far‐red light (FRL; λ = 700–800 nm). These cyanobacteria are defined as far‐red light‐utilizing cyanobacteria (FRLCyano), including two groups: (1) chlorophyll d‐producing Acaryochloris spp. and (2) polyphyletic cyanobacteria that produce chlorophylls d and f in response to FRL. Numerous ecological studies examine pigments, such as chlorophylls d and f, to investigate the presence of FRLCyano in the environment. This method is not ideal because it can only detect FRLCyano that have made chlorophylls d or f. Here we develop a new method, far‐red cyanobacteria identification (FRCI), to identify FRLCyano based on 16S rRNA gene sequences. From public databases and published articles, 62 16S rRNA gene sequences of FRLCyano were extracted. Comparing with related lineages, we determined that 97% sequence identity is the optimal cut‐off for distinguishing FRLCyano from other cyanobacteria. To test the method experimentally, we collected samples from 17 sites in Taipei, Taiwan, and conducted VL and FRL enrichments. Our results demonstrate that FRCI can detect FRLCyano during FRL enrichments more sensitively than pigment analysis. FRCI can also resolve the composition of FRLCyano at the genus level, which pigment analysis cannot do. In addition, we applied FRCI to published datasets and discovered putative FRLCyano in diverse environments, including soils, hot springs and deserts. Overall, our results indicate that FRCI is a sensitive and high‐resolution method using 16S rRNA gene sequences to identify FRLCyano. [ABSTRACT FROM AUTHOR]

The use of nanotechnology in agriculture has a positive influence on the food industry along with opening a new area of research in agroecosystems. In this paper, Iron (III) Oxide (Fe2O3) nanoparticles (FeONPs) were treated with onion (Allium cepa L.) seeds at various concentrations (1mM to 100mM) to investigate the effects on biochemical parameters, photosynthetic traits, and oxidative stress responses of seedlings. FeO-NPs were characterized using UV-Vis Spectroscopy (UV-Vis) and Scanning Electron Microscopy (SEM). Positive effects were observed in seed germination and the growth of seedlings at lower NPs concentrations. The germination percentage, photosynthetic pigments, and nutritional contents of seedlings were enhanced by 5 mM to 10 mM NPs treatments, also significant decrease in the parameters was not observed at higher concentrations. Antioxidant enzyme studies which could throw light on the toxicity of NPs indicated that FeO-NPs at high levels resulted in lower stress rates whereas the low to moderate concentrations of FeO-NPs were beneficial to the plants. In general, the results indicated that FeO-NPs at low concentrations (5mM) could be useful for onion germination, growth, and biomass production. An increase in the content of antioxidant enzymes at higher concentrations of FeO-NPs pointed towards the plant defence mechanisms against oxidative stress induced by FeONPs at high (50mM) concentrations. The study gives the effects of Iron oxide nanoparticles on growth, photosynthetic traits, and biochemical parameters of onion seedlings. [ABSTRACT FROM AUTHOR]

β-Carotene is one of the economically important carotenoids, having functions as the antioxidant to remove harmful free radicals and as the precursor for vitamin A and other high-valued xanthophyll such as zeaxanthin and astaxanthin. Lycopene cyclase plays an important role in the branching of β-carotene and α-carotene. Aiming to develop the microalgae with enhanced β-carotene productivity, the CrtY gene from bacterium Pantoea agglomerans was integrated into Chlamydomonas reinhardtii. The lycopene-producing E. coli harboring CrtY gene produced 1.59 times of β-carotene than that harboring DsLcyb1 from Dunaliella salina (a microalga with abundant β-carotene), confirming the superior activity of CrtY on β-carotene biosynthesis. According to the pigment analysis by HPLC, in microalgal transformants that were confirmed by molecular analysis, the expression of CrtY significantly increased β-carotene content from 12.48 mg/g to 30.65 mg/g (dry weight), which is about 2.45-fold changes. It is noted that three out of five transformants have statistically significant higher amount of lutein, even though the increment was 20% in maximum. Besides, no growth defect was observed in the transformants. This is the first report of functional expression of prokaryotic gene in eukaryotic microalgae, which will widen the gene pool targeting carotenoids biosynthesis using microalgae as the factory and thereby provide more opportunity for high-valued products engineering in microalgae. [ABSTRACT FROM AUTHOR]

To investigate the influence of nitrogen (N) and phosphorus (P) availability on the periphytic algal biomass and assemblage composition (by pigment analysis) in the eutrophic lake, natural littoral intact sediment cores in a subtropical eutrophic lake (Lake Taihu) were collected, and subjected to three levels of water N and P loading (N-P [mg. L−1]: 1.5, 0.075; 2.5, 0.125; 3.5, 0.175) in the tanks, eighteen artificial substances (glass slides) were fixed at three water depths (1, 17, and 33 cm above the surface sediment) for development of periphytic algae in each tank, respectively. The results showed that the biomass of periphytic algae on artificial substance was significantly enhanced with increasing N and P levels in water column and water depth (p < 0.05), while sediment-associated periphytic algae did not significantly increase with increasing N and P levels in water column. The development of sediment-associated periphytic algae changed the phosphorus form, calcium-bound phosphorus and inorganic phosphorus in the sediments decreased slightly, and the total phosphorus and organic phosphorus in the sediments increased. Our results suggest that N and P availability is conducive to the development of periphytic algae in subtropical eutrophic shallow lakes in spring. [ABSTRACT FROM AUTHOR]

Copper from sulfate baths without and with added inorganic pigment particles based on strontium aluminate doped with europium and dysprosium (SrAl2O4: Eu2+, Dy3+) was electrodeposited on a brass cathode by a galvanostatic regime. Morphological, structural, and roughness analysis of the pigment particles, the pure (pigment-free) Cu coating, and the Cu coatings with incorporated pigment particles were performed using SEM, XRD, and AFM techniques, respectively. Hardness and creep resistance were considered for the examination of the mechanical properties of the Cu coatings, applying Chicot–Lesage (for hardness) and Sargent–Ashby (for creep resistance) mathematical models. The wettability of the Cu coatings was examined by the static sessile drop method by a measurement of the water contact angle. The incorporation of pigment particles in the Cu deposits did not significantly affect the morphology or texture of the coatings, while the roughness of the deposits rose with the rise in pigment particle concentrations. The hardness of the Cu coatings also increased with the increasing concentration of pigments and was greater than that obtained for the pigment-free Cu coating. The presence of the pigments caused a change in the wettability of the Cu coatings from hydrophilic (for the pigment-free Cu coating) to hydrophobic (for Cu coatings with incorporated particles) surface areas. [ABSTRACT FROM AUTHOR]

Summary: Genetic engineering of flower color provides biotechnological products such as blue carnations or roses by accumulating delphinidin‐based anthocyanins not naturally existing in these plant species. Betalains are another class of pigments that in plants are only synthesized in the order Caryophyllales. Although they have been engineered in several plant species, especially red‐violet betacyanins, the yellow betaxanthins have yet to be engineered in ornamental plants.We attempted to produce yellow‐flowered gentians by genetic engineering of betaxanthin pigments. First, white‐flowered gentian lines were produced by knocking out the dihydroflavonol 4‐reductase (DFR) gene using CRISPR/Cas9‐mediated genome editing.Beta vulgaris BvCYP76AD6 and Mirabilis jalapa MjDOD, driven by gentian petal‐specific promoters, flavonoid 3′,5′‐hydroxylase (F3′5′H) and anthocyanin 5,3′‐aromatic acyltransferase (AT), respectively, were transformed into the above DFR‐knockout white‐flowered line; the resultant gentian plants had vivid yellow flowers. Expression analysis and pigment analysis revealed petal‐specific expression and accumulation of seven known betaxanthins in their petals to c. 0.06–0.08 μmol g FW−1.Genetic engineering of vivid yellow‐flowered plants can be achieved by combining genome editing and a suitable expression of betaxanthin‐biosynthetic genes in ornamental plants. [ABSTRACT FROM AUTHOR]

Time series analyses of pigment concentrations are key to understanding past aquatic ecosystem dynamics. As lake sediments provide a window into longer‐term changes, innovative paleolimnological chlorophyll quantification could provide impactful insights into past environmental processes. Lab‐based hyperspectral imaging of sediment cores is an emerging technique to develop rapid, non‐destructive, high‐resolution chlorophyll inferences but it requires more extensive vetting. Despite recent advances in model development, there is still a knowledge gap about the reliability of chlorophyll models when applied in lakes with diverse properties, as well as the potential confounding effects of physical sediment properties on these models. We assessed the performance of 23 chlorophyll indices based on paired measurements collected via hyperspectral imaging and spectrophotometry for 202 samples spread across seven Canadian lake sediment cores. The best performance was by a new index based on the wavelength of the red‐edge minimum point (λREMP). We tested the applicability of λREMP to a broad range of sediment cores using a database of 116 cores, and found the index to provide reliable reconstructions of ƩChl (i.e., chlorophyll a and b and their degradation products) trends in 84% of sites. Further analyses indicated that sediment characteristics including particle size, organic matter content, water content, and density had no systematic impact on ƩChl, but greater sediment brightness did increase ƩChl inferences from hyperspectral images. Hyperspectral core scanning is poised to facilitate the generation of high‐resolution chlorophyll time series data, which could greatly improve our understanding of trajectories of change from the local to global scales. [ABSTRACT FROM AUTHOR]

Abstract Pigments on four easel paintings signed by Mohammad Ghaffari (latter Kamal al-Molk), the renowned Persian painter lived from the mid-nineteenth to the mid-twentieth century, kept at the Astan-e Qods-e Razavi Museum (AQRM) in Mashhad, Iran, were identified by micro-X-ray fluorescence (µ-XRF), scanning electron microscopy—energy dispersive X-ray spectrometry (SEM–EDS) and micro-Raman spectroscopy (µ-Raman). Apart from chrome yellow, green chromium oxide and red ochre, four blue pigments including Prussian blue, artificial ultramarine blue, azurite, blue phthalocyanine PB:16 and seven white pigments including rutile, huntite, lead white, baryte, chalk, gypsum and zinc white were identified on the paintings. Based on the occurrence of rutile and blue phthalocyanine PB:16 and the fact that the signature of the paintings suggests 1875 as the date of executing the paintings, several hypotheses were argued to discuss the latter interventions and the authenticity of the works. Discussions on the birth date and other important milestones of Kamal al-Molk’s life accordingly posed serious questions on the authenticity of these paintings.

Deserts represent an extreme challenge for photosynthetic life. Despite their aridity, they are often inhabited by diverse microscopic communities of cyanobacteria. These organisms are commonly found in lithic habitats, where they are partially sheltered from extremes of temperature and UV radiation. However, living under the rock surface imposes additional constraints, such as limited light availability, and enrichment of longer wavelengths than are typically usable for oxygenic photosynthesis. Some cyanobacteria from the genus Chroococcidiopsis can use this light to photosynthesize, in a process known as far-red light photoacclimation, or FaRLiP. This genus has commonly been reported from both hot and cold deserts. However, not all Chroococcidiopsis strains carry FaRLiP genes, thus motivating our study into the interplay between FaRLiP and extreme lithic environments. The abundance of sequence data and strains provided the necessary material for an in-depth phylogenetic study, involving spectroscopy, microscopy, and determination of pigment composition, as well as gene and genome analyses. Pigment analyses revealed the presence of red-shifted chlorophylls d and f in all FaRLiP strains tested. In addition, eight genus-level taxa were defined within the encompassing Chroococcidiopsidales, clarifying the phylogeny of this long-standing polyphyletic order. FaRLiP is near universally present in a generalist genus identified in a wide variety of environments, Chroococcidiopsis sensu stricto, while it is rare or absent in closely related, extremophile taxa, including those preferentially inhabiting deserts. This likely reflects the evolutionary process of gene loss in specialist lineages. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment genes. Materials and Methods: The data of students who underwent routine CVD screening using the Ishihara color test in Kaohsiung, Southern Taiwan were analyzed. Furthermore, the DNA samples of 80 randomly selected females and four obligate carriers were analyzed. The most upstream genes, downstream genes, and the most downstream genes in the red/green pigment gene arrays were amplified separately using polymerase chain reaction (PCR), and exon 5 of each gene was analyzed. The prevalence of congenital red–green CVD in this study was 3.46% in males and 0.14% in females. The PCR analysis of the first gene, downstream gene, and last gene revealed normal patterns in 73 normal cases. Seven unusual patterns were detected in two proton carriers and five deutan carriers. Among the randomly selected females, 8.8% (7/80) were CVD carriers. The prevalence of CVD among male Taiwanese students in this study was 3.46%. Female carriers of congenital CVD can be identified by molecular analysis of the visual pigment genes. The proportion of CVD carriers among the randomly selected females was 8.8%, which was slightly higher than expected and further studies are warranted. [ABSTRACT FROM AUTHOR]

Background: Skin tone and pigmented regions, associated with melanin and hemoglobin, are critical indicators of skin condition. While most prior research focuses on pigment analysis, the capability to simulate diverse pigmentation conditions could greatly broaden the range of applications. However, current methodologies have limitations in terms of numerical control and versatility. Methods: We introduce a hybrid technique that integrates optical methods with deep learning to produce skin tone and pigmented region‐modified images with numerical control. The pigment discrimination model produces melanin, hemoglobin, and shading maps from skin images. The outputs are reconstructed into skin images using a forward problem‐solving approach, with model training aimed at minimizing the discrepancy between the reconstructed and input images. By adjusting the melanin and hemoglobin maps, we create pigment‐modified images, allowing precise control over changes in melanin and hemoglobin levels. Changes in pigmentation are quantified using the individual typology angle (ITA) for skin tone and melanin and erythema indices for pigmented regions, validating the intended modifications. Results: The pigment discrimination model achieved correlation coefficients with clinical equipment of 0.915 for melanin and 0.931 for hemoglobin. The alterations in the melanin and hemoglobin maps exhibit a proportional correlation with the ITA and pigment indices in both quantitative and qualitative assessments. Additionally, regions overlaying melanin and hemoglobin are demonstrated to verify independent adjustments. Conclusion: The proposed method offers an approach to generate modified images of skin tone and pigmented regions. Potential applications include visualizing alterations for clinical assessments, simulating the effects of skincare products, and generating datasets for deep learning. [ABSTRACT FROM AUTHOR]