Search Results (324)

(1) Background: The dun coat color, a wild-type phenotype in horses characterized by pigment dilution and primitive markings, is regulated by TBX3. This study explored the expression and localization of TBX3 in the Bider marking (a primitive mark unique to the shoulder of horses); (2) Methods: We compared skin tissues from Bider-marked and non-Bider dun Mongolian horses. Samples were collected from the Bider area (dark-colored/light-colored shoulder), dorsal midline, and croup. Histological staining, qRT-PCR, and Western blotting were used to analyze pigment distribution and TBX3 expression at mRNA and protein levels; (3) Results: Histology revealed asymmetric pigment deposition in hair shafts from light-colored areas of both Bider and non-Bider horses, whereas dark areas showed symmetric distribution. qRT-PCR and Western blotting showed TBX3 expression was significantly higher in the shoulder of non-Bider horses compared to Bider horses. Conversely, Bider horses exhibited higher TBX3 levels in all other sampled areas. Immunohistochemistry localized TBX3 protein to the epidermis and hair follicle bulbs in both groups; (4) Conclusions: In dun Mongolian horses, TBX3 expression differences between dark and light skin areas correlate with Bider markings. TBX3 is implicated in this specific pigment marking, though its upstream regulation requires further study. These findings provide key insights into the mechanism behind Bider marking formation. Full article

Silkie (SK) chickens, valued for dark meat, serve as a model to study melanin deposition in muscle. Integrated transcriptomics and metabolomics of SK vs. Arbor Acres (AA) broiler pectoralis were used to identify key molecular drivers of meat color. All birds were cage-raised under standardized temperature and light conditions with free access to feed and water. Pectoralis muscle samples were collected from 24-day-old healthy SK and AA chickens (n = 6). Transcriptome profiling identified 488 differentially expressed genes in SK chickens, with seven conserved melanogenesis genes (TYRP1, MLANA, TYR, MLPH, EDNRB2, PMEL, GPNMB) consistently upregulated across dark-pectoralis breeds, and melanogenesis and WNT pathways were activated. Co-expression network analysis highlighted SOX10 as a key hub regulator. Metabolomics quantified 129 differentially abundant metabolites. A critical finding was the significant depletion of L-tyrosine and its derivatives in SK muscle, despite upregulated melanogenesis genes. It indicates intense metabolic flux toward pigment synthesis. Integrated analyses converged on tyrosine metabolism and redox pathways: oxidized glutathione and p-coumaric acid correlated negatively with pigment deposition, while ADP-ribose and pyridoxal correlated positively. Additionally, novel inhibitors PNMT and HIBADH may modulate melanin deposition. These findings reveal a trade-off between pigment deposition and redox balance, providing molecular markers for poultry melanin-related trait improvement. Full article

The correct identification of historical artists’ earth pigments is mandatory for cultural, scholarly, and historical applications. This paper focuses on the definition of the distinctive mineralogical, geological, and geochemical properties and the discussion of the geological genesis and place of origin of the natural Fe-Mn-based earth pigment named terra d’ombra (umber). It one of the dark-brown earth pigment most widely used by Italian and European painters from the Renaissance to the nineteenth century. The terra d’ombra earth pigment is a primary chemical sediment mainly composed of Fe (oxy)hydroxide and Mn oxide, produced by the authigenic precipitation from oceanic or lacustrine waters rich in metal solutes of volcanic hydrothermal origin. The principal areas of provenance are the island of Cyprus and the Monte Amiata volcano (southern Tuscany, Italy). Its peculiar properties in painting derive from this specific mineralogical composition and genetic process, which also exclude its definition as a particular type of ochre and as a clay pigment. Further misinterpretations include confusion with pigments composed of organic materials and the erroneous attribution of the name and area of origin to the Italian region of Umbria. Full article

Two folding screens by futurist artist Giacomo Balla (1871–1958) in the collection of the Kröller-Müller Museum (the Netherlands) were investigated: Paravento con linea di velocità (1916–1917) and Paravento (1916/1917–1958). The screens are painted on both sides, the first on four canvases, stretched onto two wooden strainers and framed with painted wooden strips, and the second on wooden panels set into four painted stiles. In the past, damages on Paravento con linea di velocità were restored by conservators, while Paravento was probably first reworked by the artist himself and later restored by conservators. Yellowed varnish and discolored retouches on both screens led to a wish for treatment. The aim of this research was to gain insight into the painting techniques, layer buildup, pigments, binders, and varnishes of the two artworks. This information supported the decision making for treatment, and it broadens the knowledge on the materials used by Balla. Up to now, only a few published studies deal with the technical examination of paintings by this artist. Both folding screens were subjected to technical photography (UV, IR photography, and X-ray) and were examined with portable point X-ray fluorescence (pXRF) and Raman spectroscopy. Moreover, samples were taken. Cross-sections were studied with optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflection Fourier-transform infrared (ATR-FTIR) imaging, and micro-Raman spectroscopy. Loose samples were examined with SEM-EDX, FTIR and micro-Raman spectroscopy, and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). For Paravento con linea di velocità, all pigments and fillers of the painted canvases are compatible with the dating of the screen (1916–1917), but they differ from those on the frame. Here, rutile, in combination with various pigments, among which are blue copper phthalocyanine (PB15) and other synthetic organic pigments, was found. This indicates that the frame has been painted later, likely after the Second World War. The composition of the binders differs as well. Drying oil and pine resin have been used on the canvases, explaining the smooth and glossy appearance and solvent-sensitivity of the paint. On the frame, oil with some alkyd resin was identified. The provenance of the screen before 1972 is not clear, nor when the frame was made and painted and by whom. The results for Paravento indicate that the palettes of the two sides—painted in different styles—are comparable. Mainly inorganic pigments were found, except for the dark red areas, where toluidine red (PR3) is present. pXRF showed high amounts of zinc; cross-sections revealed that zinc white is present in the lower layers. These pigments are compatible with the dating of the screen (1916–1917). In many of the upper paint layers though, except for some green, dark red, and black areas, rutile has been identified. This indicates that these layers were applied later, likely after the Second World War. Since this folding screen was used by the artist and his family until his death in 1958, it seems likely that Balla himself reworked the screen. Full article

Melanin is the dark polymer pigment found in all kingdoms of life. Plant allomelanin, formed through the oxidation and polymerization of phenolic compounds, does not contain nitrogen; however, it possesses similar properties to melanin of animal, fungal, or bacterial origin. The black coloration of awns, spike husk edges, and even complete spikes is well-known in wheat and occurs frequently in wild, but rarely in cultivated, wheat species. Previously, anthocyanins were considered the only pigments responsible for the black coloration of wheat ears. Recently, it has been shown that the black coloration of the husks in other cereals can be attributed to melanin or anthocyanins, or both of these pigments. In this study, using standard procedures for chemical extraction of anthocyanins and melanin, ultraviolet–visible–near-infrared spectroscopy, and hyperspectral imaging, we examined the pigment in Persian wheat (Triticum carthlicum Line 5999) black-colored spikes and found that it exhibits properties characteristic of melanin rather than anthocyanins. Also, using microscopy, we show that the dark pigment in the husks and awns of mature spikes is located mainly in the dead protoplasts of epiderma and sub-epidermal sclerenchyma cells. The localization of the pigment suggests that melanin may perform some protective or sunlight-to-heat transforming function. Full article

Cercophora species, typically known as saprobes or coprophiles, have occasionally been isolated from healthy roots and have recently been recognized as endophytes. Their dark-pigmented structures suggest adaptation traits similar to dark septate endophytes, although their symbiotic potential remains unclear. This study isolated and characterized Cercophora sp. NPKC241 from mung bean roots grown under artificial drought in soils with different fertilization histories, using PCR-based DNA sequencing and morphological observation. Its effects on legume growth were subsequently evaluated through pot inoculation experiments under drought. These experiments focused on mung bean, a species known to exhibit significant reductions in chlorophyll content and yield under drought conditions. Among 29 isolates, Cercophora sp. consistently promoted legume growth. In mung bean, it increased shoot and root mass, chlorophyll content, and root elongation under both optimal and water-limited conditions. Under drought, inoculated plants showed approximately threefold higher chlorophyll levels, two- to threefold greater biomass, and roots approximately 5 cm longer than the control, indicating mitigation of drought-induced physiological decline. These findings suggest that Cercophora sp. can act as a beneficial root-associated fungus, enhancing legume performance under drought. Future studies will further explore this interaction by underlying physiological mechanisms and the field-level application potential. Full article

The spectral characteristics of harmful insect pests in wheat fields were characterised using hyperspectral imaging for the first time. The analysis of spectral profiles revealed that reflectance is determined by the structure of the insect’s chitin and the colouration of its body surface. Insects with lighter or more vivid colours (white, yellow, or green) showed higher reflectance values compared to those with predominantly dark pigmentation. Reflectance was also influenced by the presence of wings, surface roughness, and the age of the insect. Each species exhibited distinct spectral patterns that allowed for differentiation not only from other insect species but also from the plant background. A classification model using PLS-DA was developed and demonstrated high accuracy in identifying 12 pest species, confirming the strong potential of hyperspectral imaging for species-level classification. The results validate the PLS-DA method for differentiating insects based on spectral characteristics and underscore the reliability of this approach for automated monitoring systems to detect phytophagous pests in crop fields. This technology could reduce insecticide use by 30–40% through targeted application. The research has both scientific and economic significance, laying the groundwork for integrating machine learning and computer vision into agricultural monitoring. It supports the advancement of precision farming and contributes to improved global food security. Full article

This article presents the results of a comprehensive study aimed at developing automated diagnostic methods for identifying spring wheat phytopathologies using hyperspectral imaging (HSI). The research aimed to create an effective plant disease detection system, including at the early stages, which is critically important for ensuring food security in regions where wheat plays a key role in the agro-industrial sector. The study analyses the spectral characteristics of major wheat diseases, including powdery mildew, fusarium head blight, septoria glume blotch, root rots, various types of leaf spots, brown rust, and loose smut. Healthy plants differ from diseased ones in that they show a mostly uniform tone without distinct spots or patches on hyperspectral images, and their spectra have a consistent shape without sharp fluctuations. In contrast, disease spectra, differ sharply from those of healthy areas and can take diverse forms. Wheat diseases with a light coating (powdery mildew, fusarium head blight) exhibit high reflectance; chlorosis in the early stages of diseases (rust, leaf spot, septoria leaf blotch) exhibits curves with medium reflectance, and diseases with dark colouration (loose smut, root rot) have low reflectance values. These differences in reflectance among fungal diseases are caused by pigments produced by the pathogens, which either strongly absorb light or reflect most of it. The presence or absence of pigment production is determined by adaptive mechanisms. Based on these patterns in the spectral characteristics and optical properties of the diseases, a classification model was developed with 94% overall accuracy. Random Forest proved to be the most effective method for the automated detection of wheat phytopathogens using hyperspectral data. The practical significance of this research lies in the potential integration of the developed phytopathology detection approach into precision agriculture systems and the use of UAV platforms, enabling rapid large-scale crop monitoring for the timely detection. The study’s results confirm the promising potential of combining hyperspectral technologies and machine learning methods for monitoring the phytosanitary condition of crops. Our findings contribute to the advancement of digital agriculture and are particularly valuable for the agro-industrial sector of Central Asia, where adopting precision farming technologies is a strategic priority given the climatic risks and export-oriented nature of grain production. Full article

Background/Objectives: Pigmented lesions of the genital area are of commonly occurrence, with population-based incidence estimated around 10–20%. Historically, invasive biopsy or surgical removal were recommended to obtain a definite diagnosis. Line-field confocal optical coherence tomography (LC-OCT) is a novel multimodality imaging tool, able to reproduce a “virtual biopsy” of skin lesions, offering vertical, horizontal, and three-dimensional (3D) imaging down to the mid-dermis with high-resolution real-time visualization. The aims of the study were (i) to describe the LC-OCT features in a series of benign and malignant pigmented genital lesions (PGLs), (ii) to investigate the impact of LC-OCT on the diagnostic accuracy, (iii) and to estimate the diagnostic concordance between LC-OCT and histopathology. Methods: This was a retrospective, cross-sectional study including histologically confirmed PGL investigated with LC-OCT over 2 years. Descriptive statistics were calculated for continuous and categorical variables. Diagnostic accuracy of LC-OCT and dermoscopy was compared, and the LC-OCT–histopathology diagnostic concordance was estimated. Results: A total of 96 PGLs were analyzed in 23 male and 57 female patients. Pathologic reporting consisted of 56 melanoses, 21 nevi (15 compound nevi and 6 atypical genital nevi), 10 melanomas, and 9 angiokeratomas. LC-OCT obtained higher diagnostic accuracy rather than dermoscopy; diagnostic concordance LC-OCT/histopathology was 91% (87/96; 95% CI 83.7–95.3). Melanoses were characterized by a continuous undulated junction. Common genital nevi were identified by the presence of regular dense nests, while dischoesive nests were seen in atypical genital nevi. Features of epidermal disarray with pagetoid cells, junctional atypia, and discohesive nests were observed in melanoma. Angiokeratomas showed the presence of dark vascular lacunae. Conclusions: Providing in vivo key clues with a resolution close to classic histopathology, LC-OCT may have a valuable role in the clinical management of PGLs, particularly when lesions involve large areas or are multiple in number. Full article

Streptomyces avermitilis is a soil actinobacterium and has a complex metabolism in its natural habitat. Because of this, the environmental fluctuations present in the seasons can activate or silence the biosynthetic pathways involved in its metabolism. The objective of this research was to analyze the morphological characteristics of the metabolism of Streptomyces avermitilis, isolated during the four seasons of the year and from four types of soil. Isolation was performed on oat agar ISP-3 and nystatin as an antifungal agent. The planting methods were rod drag and cross striations. The Petri dishes were incubated for 10 days at 30 °C in complete darkness. For 10 days, a colony count was performed to analyze the growth curves, as was an evaluation of the diffusible pigments in each Petri dish. The isolates presented the diffusible pigments white, yellow, orange, red and pink with a higher proportion in spring and summer compared to in autumn and winter. Under laboratory conditions, the isolates in summer presented the three phases of bacterial growth: lag (24 h), exponential (48–96 h) and stationary (120–168 h). A doubling time of 35.30–62.92 h was obtained. The morphological characteristics of the metabolism of Streptomyces avermitilis show differences according to the climatic conditions of each season of the year. Full article

Lycium ruthenicum Murr. is a highly nutritional cash crop due to its fruit-abundant anthocyanins. With the development of the fruit, the color changes from green to dark purple and the anthocyanin content gradually increases. But the molecular mechanism of the anthocyanin biosynthesis process in L. ruthenicum fruit is still unclear. Five stages of L. ruthenicum fruit based on the color of the pericarp and flesh (BS1–BS5) were used for metabolomics and transcriptomics analyses to investigate the underlying mechanisms of the pigmentation. At the BS3 stage, the anthocyanin content was significantly increased and reached the highest level at the BS5 stage. A total of 25 DAMs related to flavonoids were identified by metabolomics, presenting a gradual increase with fruit development. Delphinidin-3-O-rutinoside and petunidin-3-O-rutinoside were identified as the main anthocyanins. Transcriptome sequencing and DEG analysis identified the key structural genes and transcription factors related to anthocyanin biosynthesis. Anthocyanin accumulation was driven mainly by the upregulation of six structural genes (F3′5′H, DFR, ANS, and UFGT) and eight key transcription factors from the HB, NAC, WRKY, Tify, AP2/ERF, and bHLH families that were significantly correlated with anthocyanin content in L. ruthenicum fruit. This study reveals key candidate genes in the anthocyanin biosynthetic pathway, providing new insights for improving fruit quality. Full article

Chlorella is a valuable object of biotechnology with high productivity of biomass and metabolites. The use of Chlorella for CO₂ binding in autotrophic metabolism is also discussed. Various types of stress are used to increase the yield of valuable metabolites. One of the effective approaches may be dark stress. However, there is insufficient data to fully understand the effect of dark stress on productivity, biochemical parameters, the antioxidant system, and the rate of CO₂ fixation by Chlorella during the transfer from autotrophic culture to aphotic conditions. To study these processes, we used two-step cultivation. In the second step, the biomass was grown for 96 h on a BBM medium under standard lighting and in aphotic conditions. According to the results of the study, the metabolic systems of the studied strain of Chlorella sp. CAMU G–145 specifically react to cultivation under aphotic conditions. The greatest response was found in lipid–protein metabolism and the antioxidant defense system, which determines an increase in the overall antioxidant status of cells. At the same time, productivity, CO₂ absorption characteristics, and pigment composition of the photosynthetic system did not change after 96 h of darkening. In general, this approach is a promising strategy for increasing biotechnological productions efficiency. Full article

Rapid environmental change is reshaping freshwater ecosystems, influencing food availability and predator–prey dynamics. This study examined interactions among four freshwater invertebrates—the cnidarian Hydra viridissima (HV), the turbellarians Polycelis felina (PF) and Dugesia gonocephala (DG), and the cladoceran Daphnia magna (DM)—under controlled microcosm conditions. We investigated the effects of temperature, light regime, and predator satiation on predation intensity, prey survival, and interspecific behavior during the 24 h period. DM served as a universal prey, with survival strongly affected by both temperature and predator feeding state. Predation was generally higher at 25 °C and among hungry individuals. HV proved to be the most efficient predator and competitor, whereas DG dominated among planarians by preying on PF and adopting its dark pigmentation—a potential camouflage strategy enabling mimicry of both prey and habitat. PF responded by forming defensive groups, highlighting species-specific behavioral adaptations. PF simultaneously exhibited traits of both predators and prey. These findings demonstrate that microcosm experiments can reproducibly capture natural freshwater interaction patterns. Moreover, this study provides the first evidence of a planarian predator exhibiting both prey mimicry and environmental camouflage, revealing a novel behavioral strategy in flatworm ecology. Full article

Leaf color, as a key ornamental and quality trait in leafy vegetable sweet potato, is controlled by the coordinated regulation of multiple pigment metabolic pathways. To dissect the mechanisms underlying leaf color variation, the integrated transcriptomic and metabolomic analyses were performed on three contrasting phenotypes: green (G), yellow (Y), and purple-red (R). The results showed that purplish-red leaves accumulated the highest levels of anthocyanins (16.36 mg·g⁻¹) and total chlorophyll (2.54 mg·g⁻¹), indicating that the synergistic accumulation of anthocyanins and chlorophyll contributes to their dark pigmentation. In contrast, yellow leaves contained the lowest carotenoid content yet displayed the highest carotenoid-to-chlorophyll ratio (6.44), suggesting that reduced chlorophyll levels coupled with a relatively higher carotenoid proportion underlie the yellow phenotype. Green leaves exhibited a more balanced pigment profile, with a total chlorophyll content of 1.94 mg·g⁻¹. Transcriptomic profiling revealed elevated expression of anthocyanin biosynthetic genes CHS, CHI, F3H, and chlorophyll metabolism-related genes CHLG and CAO in purplish-red leaves, whereas carotenoid biosynthesis genes LCY and CYP97A3 showed specific regulation in yellow leaves. Collectively, these findings demonstrate that leaf color formation in leafy vegetable sweet potato is determined by the relative accumulation of chlorophylls, carotenoids, and anthocyanins, together with differential regulation of their biosynthetic pathways. This work provides novel insights into the molecular basis of leaf color variation and offers a theoretical foundation for genetic improvement of leafy vegetable sweet potato. Full article

This research investigates the biosynthesis optimization of the red pigment prodigiosin produced by Serratia marcescens 11E through submerged fermentation utilizing an alternative cheese whey-based medium, focusing on process parameters and antimicrobial properties. Four types of whey sourced from a local dairy industry were characterized, and the fermentation conditions were optimized using Plackett–Burman and central composite design methodologies, yielding up to 1.43 g/L of prodigiosin under optimal conditions, 25 °C, 200 rpm, pH 7, and 48 h of dark incubation, with whey serving as the sole carbon source. Normalization to biomass yielded 110 mg of prodigiosin per gram of dried cell weight (post-optimization), enabling meaningful comparison with prior studies. Pigment extraction was performed with acidic methanol, and identity was confirmed by UV–Vis spectrophotometry and Fourier transform infrared spectroscopy (FTIR). The antimicrobial activity of the purified pigment was also evaluated. Although cheese whey has significant nutritional value, nearly half of the global production is discarded due to high treatment costs. This study demonstrates that whey can be repurposed as a sustainable and economical fermentation medium for pigment production, which is compatible with dairy plants. This makes it a promising solution to address the underutilization of whey by cheese local producers in Mexico. Prodigiosin has diverse industrial applications, including antimicrobial, insecticidal, and antioxidant properties. These findings highlight the potential for dairy waste valorization in a circular bioeconomy, reducing environmental impacts and promoting the creation of valuable bioproducts. Full article