Search Results (270)

Liquidambar formosana Hance, a tree species in subtropical broad-leaved forests, exhibits a striking autumn leaf coloration. However, how drought stress during this period influences leaf color change remains poorly understood. In this study, two-year-old seedlings were subjected to four drought gradients. Leaf color parameters, pigment contents, cellular structure, photosynthetic physiology, and hydraulic properties were systematically measured throughout the leaf color transition period. The results show that, with increasing drought severity, leaf red-green coordinate a* increased significantly during early-to-middle stress (S1–S3), while lightness L* and yellow-blue coordinate b* increased at late stress (S4). Chlorophyll (Chl) content continuously decreased, anthocyanins (Ant) peaked at mid-stress, and carotenoids (Car) became enriched at late stress. Leaf cellular structure and hydraulic parameters declined, photosynthetic function was inhibited, and antioxidant enzyme activities showed an initial increase followed by a decrease. Correlation analysis and Random Forest models revealed that L* was strongly associated with superoxide dismutase (SOD) activity, carotenoid-to-chlorophyll (Car/Chl) ratio, and net photosynthetic rate (P_n); a* was closely linked to osmotic potential at full saturation (Ψ_sat), relative water content at the turgor loss point (RWCtlp), SOD activity, Car/Chl ratio, anthocyanin-to-chlorophyll (Ant/Chl) ratio, Ant content, transpiration rate (T_r), P_n, and main vein thickness (Mvt), while b* was primarily correlated with Ψ_sat, Car/Chl ratio, SOD activity, Ant/Chl ratio, and P_n. These statistical associations suggest multiple physiological processes are involved in leaf color change. Based on these findings, we propose a hypothetical sequence: drought initially disrupts leaf water status, leading to structural atrophy and hydraulic decline, followed by photosynthetic inhibition, activated antioxidant defense, and altered pigment accumulation, which are correlated with the sequential leaf color transition from green to red to yellow-orange in this species. Full article

Microorganisms such as Arthrobacter spp. are important agents of biodeterioration in cultural heritage (CH) environments, causing orange–yellow chromatic alterations and contributing to substrate degradation. This study evaluates two complementary tools for the rapid detection and mitigation of Arthrobacter spp.: a newly designed genus-specific RNA–fluorescence in situ hybridisation (FISH) probe (Art1420-Cy3) and an antimicrobial peptide fraction produced by Saccharomyces cerevisiae ISA 1028. The RNA-FISH probe Art1420-Cy3 showed high specificity and sensitivity, labelling 80–85% of Arthrobacter cells at 10% (v/v) formamide and enabling their detection by epifluorescence microscopy and flow cytometry. The peptide fraction exhibited pronounced bactericidal activity, reducing Arthrobacter culturability from ~10⁸ to ~10¹ CFU/mL within 48 h, while also inhibiting other biodeteriogenic microorganisms. Overall, these findings outline the basis for an integrated and CH-compatible approach that combines precise Arthrobacter cells detection and identification with targeted, biologically derived control. Although further validation using real heritage samples and application protocols specifically tailored to sensitive materials is required, this strategy shows strong potential as a sustainable alternative to conventional chemical biocides and as a practical framework for detecting and mitigating pigment-producing biodeteriogens in CH and other vulnerable environments. Full article

Paeonia delavayi displays exceptionally diverse flower colors. This study established a quantitative classification system for these colors and analyzed the relationships among pigment composition, content, and geographical distribution, providing a scientific basis for genetic diversity conservation and ornamental peony breeding. Petals from 465 plants across 30 wild populations and nurseries in central and northwestern Yunnan, China, were analyzed. Color values were quantified using CIE-Lab and Munsell color systems, while pigment content was determined using HPLC and spectrophotometry. Correlations between color values, pigments, and environmental factors were examined. The results were as follows: (1) Flower colors were classified into nine color series, each with distinct boundaries in the color value space: white (W), yellow (Y), yellow-green (YG), orange (O), orange-brown (OB), pink (P), red (R), purple-red (PR), and dark purple (DP). (2) Color values showed wide variation (a*: −23.10–65.54; b*: −4.11–94.26), indicating high diversity. (3) Yellow-category petals had high b* values (24.91–94.26), correlated with carotenoid, chlorophyll, and flavonoid content, and lacked anthocyanins. The lightness value (L*) of red-category petals was correlated with total flavonoid (TF) and total anthocyanin (ACN) content. (4) Correlation analysis showed that the formation of dark-flower colors (DP, PR, R) was significantly and positively correlated with high altitude, high soil organic carbon (SOC), and high soil total nitrogen (STN) content. The distribution of yellow-series flower colors (Y, YG) was correlated with lower altitude and weaker UV radiation, while increasing mean annual temperature (MAT) limited their distribution. (5) Analysis incorporating environmental factors showed that high-altitude areas in northwestern Yunnan, such as Shangri-La and Lijiang, had the richest flower color diversity, whereas central Yunnan’s low-altitude areas were dominated by yellow flower colors. This study indicates that the high-altitude areas of northwestern Yunnan represent the region with the richest flower color diversity in P. delavayi, and are important for the conservation of its flower color genetic diversity and as a source of genetic diversity in flower color in ornamental cultivar breeding. Full article

Crocosmia is a genus of bulbous, perennial plants from the Iridaceae family whose characteristic red to orange pigmentation suggests the presence of anthocyanins, flavonoids, and carotenoids—secondary metabolites often associated with antioxidant activity. This study aimed to characterize and compare the major pigment-related metabolites in two Crocosmia varieties (Crocosmia masoniorum “Lucifer” and Crocosmia aurea) through chromatographic (HPLC-DAD) and spectrophotometric analyses (UV-Vis), using Crocus sativus L. flowers as a reference matrix. Successfully, the major crocin trans-4-GG, the flavonol kaempferol-3-O-β-sophoroside, and the anthocyanin delphinidin-3-O-β-glucoside were quantified in Crocosmia flowers. Additional metabolites absent in Crocus sativus L. were also identified and quantified. Both Crocosmia varieties exhibited higher antioxidant capacity than Crocus sativus L. flowers, highlighting their potential for future applications in pharmaceutical, nutraceutical, or functional ingredient development. Full article

The cryptochromes (CRYs) perceive blue light to regulate various developmental and metabolic events. However, the role of CRYs in flavonoid biosynthesis and flower pigmentation in safflower (Carthamus tinctorius L.) remains unknown. In this study, we determined flower color diversity among 485 safflower genotypes using the integrated CIELAB color space parameters and cluster analysis. On this basis, distinct colors were categorized into four groups, namely white (WW), yellow (YY), orange–red (OR), and yellow–red (YR). A genome-wide association study (GWAS) via 933,444 high-quality SNPs showed CtCRY2 as a flower color variation gene. Subsequently, genomic analysis identified three genes of the CRY family, including CtCRY1.1, CtCRY1.2, and CtCRY2. In silico analysis, such as gene structure, phylogeny and cis-acting elements, suggested CtCRY1.1 as a key candidate in pigment biosynthesis and was, therefore, selected for functional validation. Overexpression of CtCRY1.1 in Arabidopsis accumulated a high flavonoid content, particularly upregulating the expression of CHS, FLS, and ANS, proving its role as a positive regulator of flavonoid biosynthesis in safflower. These findings provide insights into the molecular mechanisms underlying flower color regulation in safflower and highlight CtCRY1.1 as a new target to enhance pigment-related traits in plants. Full article

A novel bacterial strain, designated as 4-30^T, was isolated from a soil sample collected from the Kubuqi Desert in Inner Mongolia, northern China. The isolate was a Gram-stain-positive, aerobic, motile, and coccus-shaped bacterium, and its colonies were circular, opaque, convex, smooth, and orange-pigmented on Luria–Bertani agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 4-30^T belonged to the genus Planococcus. Growth occurred at 4–38 °C (optimum, 25–28 °C), pH 6.0–11.0 (optimum, pH 9.0), and in 0–10% (w/v) NaCl (optimum, 1%). Strain 4-30^T contained iso-C_14:0, anteiso-C_15:0, C_16:1 ω7c alcohol, and iso-C_16:0 as major cellular fatty acids (>10%) and MK-7 and MK-8 as predominant menaquinones. Its polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and two unidentified polar lipids. The genomic DNA G+C content was 45.9%. The average nucleotide identity (ANI) values between strain 4-30^T and the closely related species were relatively low (ANIm < 85.6%, ANIb < 82.9% and OrthoANIu < 83.3%), and the digital DNA–DNA hybridization (dDDH) between strain 4-30^T and type strains of the genus Planococcus were 20.0–26.7%. Based on phylogenetic, genotypic, chemotaxonomic, and phenotypic analyses, strain 4-30^T is considered to represent a novel species of the genus Planococcus, for which the name Planococcus circulans sp. nov. is proposed. The type strain is 4-30^T (=CDMCC 1.2409^T = KCTC 43405^T). Full article

Although the clownfish, Amphiprion ocellaris (A. ocellaris), is a popular ornamental marine fish worldwide, the mechanisms underlying color pattern variation remain unclear. Given that the Platinum-type clownfish, nearly entirely white, has high economic value, understanding the biological mechanism that accounts for the difference between orange and white colors in A. ocellaris is crucial. To investigate these coloration differences, we performed RNA sequencing analysis and identified differentially expressed genes (DEGs) by comparing white and orange skin samples from three A. ocellaris individuals. A total of 76 DEGs were detected, including 56 downregulated and 20 upregulated genes. DEG sequences were annotated using Danio rerio and Stegastus partitus as reference species, selecting the best hit based on the lowest E-value. A protein–protein interaction (PPI) network and Gene Ontology biological process terms were additionally analyzed. Several DEGs previously reported to be associated with pigmentation, including hpdb, cldn11b, sfrp5, slc2a9, slc2a11b, si:ch211-256m1.8, fhl2, rab38, and ttc39b were identified. Based on the functions of these DEGs, it is inferred that leucophores and xanthophores contribute to both white and orange coloration by modulating related genes, including slc2a11b and slc2a9. Additionally, sfrp5, sost, and sp7 genes were identified to interact with each other in the PPI analysis, with sfrp5 and sost being associated with the Wnt signaling pathway, which contributes to melanocyte specification and osteoblast differentiation. Based on these findings, we propose sost and sp7 as candidate genes that might provide insights relevant to extreme white pigmentation phenotypes, such as those observed in Platinum-type clownfish. For a clearer understanding, further studies integrating quantitative genetics and functional analyses are required. Full article

This paper explores the feasibility of producing manganese- and lead-doped luminescent materials from phosphogypsum. For the first time, orange- and red-emitting ultraviolet pigments were obtained using a sulfide matrix reduced from phosphogypsum. The resulting materials were characterized using X-ray diffraction (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy (XPS). Doping with manganese or lead cations is shown to produce luminophores whose luminescence shifts from orange to red–orange under UV radiation as lead cations replace manganese cations in the CaS:Mn_1-xPb_x solid solution. A sharp increase in red luminescence intensity was observed for CaS: Mn luminophores when they were irradiated with short-wavelength ultraviolet radiation. These results open up broad possibilities for using phosphogypsum, a high production volume (HPV) chemical waste product, to produce highly innovative products. Full article

Maize is a key staple cereal, with its cultivation improved through genetics, denser planting, and greater fertilizer use. However, little is known about the effects of nanomaterials on maize’s grain quality. This study evaluated the effect of the foliar application of orange carbon dots (o-CDs) on maize’s growth, grain yield, and quality under typical field conditions. Two ZP maize hybrids and their inbred lines were tested. The results showed a gradual increase in grain yield for the hybrids, particularly ZP 4567, which responded significantly to a 5 mg/L treatment. Increased starch content was observed in both the hybrid ZP 4567 and the inbred line L56 L026 following treatment with o-CDs at concentrations of 1 mg/L and 5 mg/L. The significant increase in oil content was observed in inbred line L56 L026. Photosynthetic parameters and pigments were elevated in both hybrids after treatments, although the antioxidative capacity remained unchanged. The findings suggest that o-CDs positively influence grain yield and quality by enhancing photosynthesis and increasing the accumulation of key biochemical compounds. This study provides novel insights into the application of carbon nanoparticles in sustainable crop production. Full article

Carotenoids and microbial lipids are valuable bioactive compounds with potent antioxidant and anti-inflammatory properties. Microbial biosynthesis provides a sustainable alternative to conventional plant extraction and chemical synthesis. Here, we report the isolation and characterization of a novel oleaginous yeast, Rhodotorula evergladensis CXCN-6, from the surface of Nymphaea ‘Gorgeous Purple’. The strain displayed intense reddish-orange pigmentation due to intracellular carotenoid accumulation. HPLC and LC–MS analyses identified torularhodin as the predominant carotenoid (m/z 563.4 [M]⁺), while lipids were rich in linoleic (C18:2), oleic (C18:1), and α-linolenic (C18:3) acids. Under optimized fermentation, CXCN-6 yielded 63.56 mg/L torularhodin and 9.83 g/L total lipids. The CXCN-6 extract showed strong DPPH and ABTS radical scavenging activities and significantly reduced intracellular ROS levels in UVA (9 J/cm²)-stimulated HaCaT cells. It also suppressed IL-6 and TNF-α secretion in LPS-activated macrophages without cytotoxicity. Collectively, these results establish R. evergladensis CXCN-6 as a novel and efficient microbial platform for the co-production of torularhodin and PUFA-rich lipids with potent antioxidant and anti-inflammatory properties, offering promising applications in nutraceutical, skincare, and functional food industries. 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

Sweet potato (Ipomoea batatas (L.) Lam.) is increasingly recognized as a functional crop due to its rich content of health-promoting phytochemicals. This study compared the phenolic compound profiles of four sweet potato varieties differing in flesh colour (purple, orange, white, and pale yellow) cultivated in three distinct regions of Hungary. The objective was to evaluate the relative effects of pigmentation and growing location on antioxidant capacity. Tubers were collected in triplicate and analyzed spectrophotometrically (UV–Vis) for vitamin C, total flavonoids, and total polyphenols. Statistical analysis using two-way ANOVA and Tukey’s HSD revealed that flesh colour had a significant effect on all antioxidant parameters (p < 0.05), whereas geographic origin did not. Purple-fleshed tubers exhibited markedly higher levels of vitamin C (21.6 mg/100 mL), flavonoids (378.7 mg/100 mL), and polyphenols (37.0 mg/100 mL) compared with the other colour groups. These findings indicate that pigmentation is a stronger determinant of antioxidant potential than cultivation region. The results highlight the promising nutritional value of Hungarian purple-fleshed sweet potato varieties, supporting their use in functional food development and sustainable agricultural diversification strategies. Full article

The identification and development of novel antimicrobials is a crucial challenge in the face of increasing antibiotic and antimycotic resistance. As such, there is growing interest in exploring the chemical diversity of natural sources, such as invasive seaweeds such as Asparagopsis armata. The valorization of such sources can further contribute to the development of bio-based industries, aligning with societal goals for environmental and economic sustainability. Therefore, a solid-liquid extraction method was performed using ethanol, and the obtained extract was studied for chemical composition elucidation, bioactivity, and toxicity evaluation. Analysis by GC-MS revealed some major chromatographic peaks, including floridoside (2-α-O-D-galactopyranosyl glycerol), glycerol, and oleamide. Also, several other smaller peaks were tentatively attributed to Low Molecular Weight Carbohydrate Derivatives, including isosaccharino-1,4-lactone, which had only been reported once in nature. The extract demonstrated significant antioxidant activity as measured by Ferric Reducing Antioxidant Potential and Oxygen Radical Absorption Capacity, but not by Lipid Peroxidation Inhibitory Potential assays, which is in line with its polar nature. The extract exhibited antimicrobial activity against various microorganisms, with a MIC of 2 mg/mL observed for Staphylococcus epidermidis, Vibrio parahaemolyticus, and the three yeast strains tested. Moreover, the extract inhibited the growth and phenotypic changes in filamentous fungi, which may result in reduced virulence. Specifically, the extract inhibited sporulation in Aspergillus fumigatus and orange pigmentation in Fusarium graminearum, possibly by a reduction in the production of aurofusarin, rubrofusarin, and mycotoxins. In vitro cell viability assays in 3T3, RAW264.7, and HaCaT demonstrated the extract was not cytotoxic or presented low cytotoxicity at concentrations up to 0.1 mg/mL, but a strong cytotoxic effect was observed at 1 mg/mL. At non-cytotoxic concentrations, the ethanol extract inhibited up to 48% of NO production in LPS-stimulated RAW264.7. This may indicate that anti-inflammatory activity may add to the antimicrobial activity in human and animal systemic and topical applications of the extract. In this work, new molecules were reported in A. armata, and the bioactivities reported were novel for this extract and algal species—especially through the choice of uncommon but very relevant pathogens to study. Our findings are a valuable contribution to addressing challenges in human and animal health, food and feed technology, as well as animal husbandry and agriculture. Full article

The orange mullein is a biennial plant whose tall yellow flower spikes contain mucilage, saponins, and other medicinal compounds that have a beneficial effect on respiratory problems. As light quality is known to influence plant morphology and physiology, with effects often depending on the species, understanding these responses in mullein is of particular interest. Therefore, this study aimed to investigate the combined effects of different light-emitting diodes (white, red and blue) and their corresponding photon flux densities (PPFD) on the morphology, pigment composition, antioxidant activity, fluorescence parameters and OJIP transient curves in mullein (Verbascum phlomoides L.) seedlings. Seedlings grown under blue light, which had relatively higher PPFD, showed the greatest root length, leaf number, leaf and root fresh and dry biomass. Red light, with lower PPFD, resulted in the lowest values for these parameters. Compared to white light, pigment analysis showed that blue light increased chlorophyll a, total chlorophyll, carotenoid content, and the Chl a/b ratio. Also, blue light enhanced antioxidant activity, as well as the accumulation of phenolic compounds and flavonoids, indicating that it appeared to enhance the synthesis of secondary metabolites under this spectrum. In contrast, seedlings under red light exhibited the lowest ferric reducing antioxidant power values and tended to reduce levels of phenols and flavonoids, indicating a weaker antioxidative response. It was found that white light appeared to enhance the photochemical activity of photosystem II (PSII) and energy dissipation. Blue light improved linear electron transport, photosystem I (PSI) activity and overall photosynthetic performance. Red light preferentially increased electron flow towards the final acceptors of PSI, affecting the terminal part of the electron transport chain. Analysis of OJIP curves revealed spectrum and intensity-specific changes in the L, K, H, and G bands, demonstrating that light treatments with differing PPFDs selectively modulate PSII and PSI function. Full article

Monascus pigments (MPs), natural food colorants produced by Monascus spp., have been traditionally used in China and Southeast Asia. Our prior work demonstrated that altered cell wall architecture in M. purpureus M9 significantly enhances pigment synthesis and secretion, although biosynthetic regulation under combined cell wall stress and acidic conditions remains unexplored. This study employed comparative transcriptomics to investigate coordinated regulation of MP production by pH stress and modified cell wall polysaccharides in wild-type (M9-WT) and UDP-galactopyranose mutase-deficient (M9-KO) strains at pH 5.0 and 3.0. At pH 5.0, MpglfA knockout enhanced MP secretion through cell wall restructuring involving differential expression total 67 genes (DEGs) of primary metabolism. Acidic stress (pH 3.0) significantly increased DEGs (168 up/643 down) in M9-KO versus M9-WT, inducing amino acid/fatty acid degradation pathways that generate MP precursors (acetyl-CoA/propionyl-CoA) and accelerating metabolic transition toward secondary metabolism. Concurrently, M9-KO adopted survival strategies featuring growth suppression and acid stress pathway activation to coordinate osmotic adaptation. Glucan synthase genes exhibited greater pH sensitivity than galactomannan-related genes, while MP biosynthetic genes were transcriptionally repressed in M9-KO under higher acidity. KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment and the series test of cluster confirmed that primary metabolic pathways, particularly nitrogen/carbon metabolism, critically regulate MP biosynthesis. Transcriptomic analysis under limited pH regimes revealed that antagonistic regulators ROX1 and SPT15 mediated pH-responsive transcriptional reprogramming, potentially regulating specific MP biosynthesis (e.g., monascus orange pigments). This work established theoretical foundations for manipulating cell wall composition to enhance MP production efficiency. Full article