Pigment Synthesis Research Articles

Looking at the Modern to Better Understand the Ancient: Is It Possible to Differentiate Mars Pigments from Archaeological Ochres?

This article offers a discussion of the possibility of distinguishing ochres from Mars pigments. The discussion addresses technological, archaeological, and artistic aspects. Natural earth pigments such as ochres, siennas, and umbers have been widely used from the Paleolithic to the present day and still find wide application despite the development of synthetic iron oxide pigment synthesis processes, called Mars pigments. The potential ability of today’s analytical techniques to distinguish between two classes of pigments of the same color with very similar chemical composition—but perhaps sufficient for reliable recognition—is also discussed. The paper begins by addressing the proper use of the terms “ochres” and “Mars pigments” and their accurate identification in artworks. It reviews the literature on the chemical–mineralogical characterization of yellow and red iron pigments and analyzes pigment catalogs to understand how companies distinguish ochres from Mars pigments. An experimental analysis using External Reflection Infrared Spectroscopy (FTIR-ER) compared painting samples made with natural ochres and Mars pigments, confirming the literature findings and suggesting future research directions. Key differences such as hematite in yellow ochres and specific spectral peaks in red ochres support the potential of FTIR-ER spectroscopy as a noninvasive tool for distinguishing pigments, especially for fragile artifacts and archaeological applications.

Enhancing cold tolerance in tobacco through endophytic symbiosis with Piriformospora indica

Tobacco, a warm-season crop originating from the Americas, is highly susceptible to cold stress. The utilization of symbiotic fungi as a means to bolster crops’ resilience against abiotic stresses has been proven to be a potent strategy. In this study, we investigated the effect of endophytic fungus Piriformospora indica on the cold resistance of tobacco. When exposed to cold stress, the colonization of P.indica in tobacco roots effectively stimulates the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX). This, in turn, reduces the accumulation of reactive oxygen species (ROS), thereby mitigating oxidative damage. Additionally, P. indica elevates the levels of osmolytes, such as soluble sugars, proline, and soluble proteins, thus facilitating the restoration of osmotic balance. Under cold stress conditions, P. indica also induces the expression of cold-responsive genes. Furthermore, this fungus not only enhances photosynthesis in tobacco by stimulating the synthesis of photosynthetic pigments, strengthening Rubisco activity, and elevating PSII efficiency, but also fortifies tobacco’s nitrogen assimilation by inducing the expression of nitrate transporter gene and activating enzymes related to nitrogen assimilation. Consequently, this synergistic optimization of nitrogen and carbon assimilation provides a solid material and energetic foundation for tobacco plants to withstand cold stress. Our study demonstrates that a mycorrhizal association between P. indica and tobacco seedlings provides multifaceted protection to tobacco plants against low-temperature stress and offers a valuable insight into how P. indica enhances the cold tolerance of tobacco.

Magnetized Irrigation and its Potential in Sustainable Agriculture: A Review

Magnetisation in agriculture is not a conventional method. It has tremendous implications in the crop production as well as mitigating the poor quality soil and water conditions. This reviews looks into the changes that occur in the properties of water on magnetization and the changes in the physico-chemical of soil that are affected by magnetic water. The practical application of magnetic irrigation in agriculture are reviewed based on recent researches. Magnetisaton positively influences the seed germination, seedling establishment, vegetative growth and yield of treated plants. Magnetic irrigation boosts the anti-oxidant and enzyme activity, enhances the plant metabolism and synthesis of plant pigments for coping up the adverse growth conditions. The remediation of poor quality irrigation water and waste water management are another fields where magnetization can be effectively utilized. Magnetic water can be used to alleviate abiotic stresses such as salinity and drought stresses. Magnetised irrigation is a suitable alternative for reduced water requirement and improved water use efficiency. Hence magnetised irrigation is a promising scientific method to boost crop production, while being sustainable and environmentally safe.

Sll1019 and slr1259 encoding glyoxalase II improve tolerance of Synechocystis sp. PCC 6803 to methylglyoxal- and ethanol- induced oxidative stress by glyoxalase pathway.

The glyoxalase pathway is the primary detoxification mechanism for methylglyoxal (MG), a ubiquitous toxic metabolite that disrupts redox homeostasis. In the glyoxalase pathway, glyoxalase II (GlyII) can completely detoxify MG. Increasing the activity of the glyoxalase system can enhance the resistance of plants or organisms to abiotic stress, but the relevant mechanism remains largely unknown. In this study, we investigated the physiological functions of GlyII genes (sll1019 and slr1259) in Synechocystis sp. PCC 6803 under MG or ethanol stress based on transcriptome and metabolome data. High-performance liquid chromatography (HPLC) results showed that proteins Sll1019 and Slr1259 had GlyII activity. Under stress conditions, sll1019 and slr1259 protected the strain against oxidative stress by enhancing the activity of the glyoxalase pathway and raising the contents of antioxidants such as glutathione and superoxide dismutase. In the photosynthetic system, sll1019 and slr1259 indirectly affected the light energy absorption by strains, synthesis of photosynthetic pigments, and activities of photosystem I and photosystem II, which was crucial for the growth of the strain under stress conditions. In addition, sll1019 and slr1259 enhanced the tolerance of strain to oxidative stress by indirectly regulating metabolic networks, including ensuring energy acquisition, NADH and NADPH production, and phosphate and nitrate transport. This study reveals the mechanism by which sll1019 and slr1259 improve oxidative stress tolerance of strains by glyoxalase pathway. Our findings provide theoretical basis for breeding, seedling, and field production of abiotic stress tolerance-enhanced variety.IMPORTANCEThe glyoxalase system is present in most organisms, and it is the primary pathway for eliminating the toxic metabolite methylglyoxal. Increasing the activity of the glyoxalase system can enhance plant resistance to environmental stress, but the relevant mechanism is poorly understood. This study revealed the physiological functions of glyoxalase II genes sll1019 and slr1259 in Synechocystis sp. PCC 6803 under abiotic stress conditions and their regulatory effects on oxidative stress tolerance of strains. Under stress conditions, sll1019 and slr1259 enhanced the activity of the glyoxalase pathway and the antioxidant system, maintained photosynthesis, ensured energy acquisition, NADH and NADPH production, and phosphate and nitrate transport, thereby protecting the strain against oxidative stress. This study lays a foundation for further deciphering the mechanism by which the glyoxalase system enhances the tolerance of cells to abiotic stress, providing important information for breeding, seedling, and selection of plants with strong stress resistance.

Minimizing the cobalt content in black ceramic pigments by Design of Experiments

This paper presents a comprehensive optimization strategy for the synthesis of new black ceramic pigments with low cobalt content while maintaining a single-phase spinel structure. The aim is to achieve comparable hues to those of an industrial benchmark containing five transition metals while minimizing the environmental impact. Exploring all possible compositions deriving from a five–component system (Cr, Mn, Fe, Co and Ni), through traditional methods would be extremely time consuming to guarantee an efficient sampling, requiring high experimental efforts. Hence, to identify the best black compositions, we employed a chemometric approach, the Design of Experiments, aiming to investigate the compositional domain derived by varying the metals stoichiometry within fixed boundaries to identify optimal pigment compositions. The resulting pigments (comprising Cr, Fe and Co), despite the lower cobalt content, exhibited optimal colorimetric properties comparable to the standard benchmark, with experimental ΔE values comparable to the ones predicted by the model. In particular, the pure spinels Cr1.05Fe1.05Co0.9O4 and Cr1.2Fe1.05Co0.75O4 displayed low lightness and chroma (L∗ = 2.4; C∗ = 5 and L∗ = 1.12; C∗ = 1.1, respectively), providing deep and dark black tonality. These compositions exhibit promising colorimetric performance and chemical stability, offering potential benefits for industrial applications.

Production of iron oxide pigments using metallurgical wastes

To produce paints and varnish coatings, there is an opportunity to use a waste of metallurgical production of Yakovlevsky mining and processing complex, Cherepovets, Russia. This waste contains iron oxide as iron oxide pigment. It could be used as an analogue to iron oxide pigment already existing on the market. The authors studied the pigment properties of the waste and the opportunity of using it as a raw material for the synthesis of red iron oxide pigment. The article gives recommendations on the use of the obtained product and shows the opportunity of its application for paint and varnish coatings.

Synthesis, characterization, and ameliorative effect of iron oxide nanoparticles on saline-stressed Zea mays

High soil salinity induces osmotic and ionic stress that threaten crop production worldwide and affect food security. This study evaluated the ameliorative effects of iron oxide nanoparticles on salinized Zea mays. Iron oxide nanoparticles were synthesized using an aqueous leaf extract of Diodella sarmentosa, and the results of the characterization using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), transmission electron microscope (TEM), UV–visible spectrophotometer, and scanning electron microscope (SEM) revealed the presence of polydisperse spherical iron oxide nanoparticles (FeONPs) with a light absorption peak at 290 nm, and a size ranging from 3.03 nm to 87.04 nm. Daily foliar application of FeONPs on the salinized Zea mays for 10 days, significantly (p < 0.05) improved the plant’s photosynthetic pigments (total chlorophyl (175.71 %), chlorophyll a (256.34 %), chlorophyll b (77.01 %), carotenoid (39.36 %), root length (9.87 %), and antioxidant enzyme activities, compared to the untreated and bulk FeCl3·6H2O-treated controls. Since iron is known to promote photosynthetic pigment synthesis, the enhanced photosynthetic indices observed in the FeONPs-treated pot compared to the bulk FeCl3·6H2O-treated pot, may have resulted from the size-aided absorption of the FeONPs more than FeCl3·6H2O From the findings, it can be deduced that FeONPs can improve the growth and development of saline-stressed Zea mays by enhancing the activities of the antioxidant enzymes, while improving the photosynthetic pigments of the plant.

Enhancing carotenoid accumulation in Dunaliella bardawil by combined treatments with fulvic acid and optimized culture conditions

Natural carotenoids from microalgae have received more attention as an alternative source. In this study, fulvic acid (FA), a plant growth regulator, was used to enhance carotenoid accumulation in microalgae Dunaliella bardawil rich in lutein. However, the addition of FA promoted pigment synthesis but also exhibited an inhibitory effect on biomass. Therefore, the optimization of culture conditions was performed to further enhance carotenoid accumulation, including high light stress (10,000 lx) and the two-stage cultivation comprising 1-aminocyclopropane-1-carboxylic acid (ACC) and FA. Under both culture conditions, the growth inhibition caused by FA was alleviated, leading to a further increase in the contents of chlorophylls and carotenoids. HPLC analysis revealed that the production of lutein, α-carotene and β-carotene increased by 0.44-, 0.37- and 0.54-fold under the treatment of 400 mg/L FA with high light intensity and 0.91-, 1.15- 0.29-fold under the two-stage cultivation comprising 11 mM ACC and 500 mg/L FA. Furthermore, algal cells under FA treatment and the two-stage cultivation stained with Bodipy505/515 emitted stronger fluorescence under a laser confocal microscope, suggesting that lipid accumulation was increased. Additionally, the transcription levels of carotenogenic genes were also found to be up-regulated by qRT-PCR. These results indicated an enhancement in both the storage capacity and synthesis of carotenoids in D. bardawil. This study revealed the potential application of plant growth regulators in promoting carotenoid accumulation in D. bardawil which could be further improved by optimizing the culture conditions, providing a reference for efficient carotenoid production in microalgae.

Study of the Use of Oxygenated Water as a Non-Toxic Molecule Model for Catalytic Testing of Pozzolana-PN and Iron-Based NOx Reducing Catalysts

During previous catalytic tests on the reducing power of NOx catalysts based on pozzolana and PN-black citric acid polymer, it was found that the use of the NO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; model molecule poses a significant health and environmental risk. Thus, a project was launched to find another, much less harmful model molecule. Hydrogen peroxide H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; was chosen, a molecule naturally secreted by the body to prevent pigment synthesis, with disinfectant, antiseptic and whitening properties widely used in various activities, including cosmetics. Consequently, catalytic tests of NOx-reducing power using hydrogen peroxide H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; as a model molecule were carried out on two catalysts based on pozzolana and PN-black polymer of citric acid, PNP-Fe-water-15% and PNP-Fe-ethanol-15%, differing in the solvent used during their syntheses according to a procedure detailed in the bibliography and this manuscript. Pozzolana is a volcanic rock widespread in the volcanic mountains in the Vakinankaratra region of Madagascar. Its use as a support for catalysts based on PN-black polymer of citric acid and Iron-Fe enabled us to synthesize various catalysts, the characteristics and synthesis methods of which are detailed in this manuscript. In short, the catalytic test with hydrogen peroxide was conclusive, enabling a pragmatic comparison of the two catalysts tested, with the result that the catalyst synthesized with water PNP-Fe-water-15% is more active than the catalyst synthesized with ethanol PNP-Fe-ethanol-15%. This is due to the quality and difference in dispersion of the PN-black polymer molecules depending on the solvent used, which can have an impact on the nature of the catalyst surfaces and certain characteristics such as porosity. This dispersion is confirmed and viewed using an optical microscope to visualize the surface of a catalyst grain. Kinetic results from two proposed mechanisms for the reduction of H&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;O&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; hydrogen peroxide molecules using PNP-Fe catalysts also confirmed not only the proposed mechanisms, but also the higher activity of PNP-Fe catalysts synthesized with water, whose kinetic constants are much higher than those synthesized with ethanol.

Synthesis of Ceramic Pigments with Willemite Structure and Their Use for Blue Glazes

Synthesis of Ceramic Pigments with Willemite Structure and Their Use for Blue Glazes

Application Techniques and Concentrations of Ascorbic Acid to Reduce Saline Stress in Passion Fruit

Salinity restricts the growth of irrigated fruit crops in semi-arid areas, making it crucial to find ways to reduce salt stress. One effective strategy is using eliciting substances like ascorbic acid. In this context, the objective of this study was to evaluate the effects of application methods and concentrations of ascorbic acid on the morphophysiology and production of sour passion fruit irrigated with saline water. The experiment was organized using a factorial randomized block design (3 × 3 × 2) with three application methods (soaking, spraying, and soaking and spraying), three concentrations of ascorbic acid (0, 0.8, and 1.6 mM) and two levels of electrical conductivity of irrigation water—ECw (0.8 and 3.8 dS m−1). Foliar spraying of ascorbic acid at a concentration of 0.8 mM mitigated the effects of salt stress on the relative water content of leaves, the synthesis of photosynthetic pigments, gas exchange, and total production of sour passion fruit when irrigated with ECw of 3.8 dS m−1. Plants grown with water of 0.8 dS m−1 and under foliar application of 0.8 mM of ascorbic acid achieved the maximum growth in stem diameter and the greatest volume of pulp in the fruits.

Physicochemical and Color Changes During Fruit Ripening in Pepper Species (C. annuum L., C. baccatum L., and C. chinense Jacq.) Exposed to Salt Stress

This study examines the impact of salt stress on the physicochemical and color characteristics of three pepper species (Capsicum annuum L., Capsicum baccatum L., and Capsicum chinense Jacq.) at different ripening periods. Peppers were exposed to 0 mM, 50 mM, and 100 mM NaCl during the green, breaking, and red ripening periods. The results showed that salt stress significantly influenced moisture content, total ash, pH, titratable acidity, water activity, and color parameters. C. chinense had the highest moisture content and water activity, while C. annuum demonstrated a higher total ash content and pigment density (ASTA value). As fruits ripened, moisture content decreased, and total ash content increased. Salt stress caused reductions in water activity, pH, and titratable acidity, with high salt concentrations leading to increased water loss and a decline in fruit quality. Furthermore, salt stress reduced color parameters and ASTA values, indicating suppressed carotenoid pigment synthesis. The study highlights the importance of developing salt-tolerant pepper varieties, as salt stress negatively impacts the physiological and biochemical quality of peppers. These findings suggest that appropriate agronomic strategies and careful environmental monitoring are essential for sustainable pepper production, particularly in areas with saline soils. The results provide valuable insights into the mechanisms through which salt stress affects pepper fruit quality and suggest avenues for improving crop resilience.

Evaluating the Efficacy of Actinidia deliciosa (Kiwi Fruit) Extract in Inhibiting Pseudomonas aeruginosa Biofilm Formation: An In Vitro Study With Therapeutic Implications.

Background Gram-negative Pseudomonas aeruginosa is a common bacteria that is well-known for its capacity to build biofilms, which are organized cell communities encased in a self-produced polymeric matrix. Treating infections becomes more challenging due to biofilms' capacity to provide immunity and resistance to antibiotics. The search for novel anti-biofilm agents has gained significant momentum, and the diverse range of bioactive compounds found in natural products offers a promising avenue. Rich in vitamins, antioxidants, and various phytochemicals, Actinidia deliciosa (kiwi fruit) has demonstrated potential as an antibacterial agent. Aim of the study This study aims to assess the efficacy of A. deliciosa extract in inhibiting biofilm formation by P. aeruginosa in vitro, providing valuable insights into its potential as a natural therapeutic agent for preventing recurrent bacterial infections. Materials and methodology The antibacterial and antibiofilm properties of A. deliciosa (kiwi fruit) methanolic extract were assessed in this study against P. aeruginosa (PAO1). The fruit was gathered, examined by a botanist for authenticity, and then cold macerated in methanol to create an extract. A two-fold broth dilution procedure was used to calculate the minimum inhibitory concentration (MIC), and agar well-diffusion was used to evaluate the antimicrobial activity. Pyocyanin pigment quantification was carried out after the extract was applied, and the antibiofilm impact was evaluated using a crystal violet assay. GraphPad Prism (GraphPad Software, San Diego, CA) was used for statistical analysis. Results Based on our findings, A. deliciosa was shown to have significant antibacterial and antibiofilm properties against P. aeruginosa (PAO1). At 5 mg/mL, the methanolic extract of A. deliciosa exhibited antibacterial activity with an 8 mm zone of inhibition and suppressed PAO1 growth. At 2.5 mg/mL and 1.25 mg/mL doses, PAO1 significantly decreased the production of biofilms by 60% and 29%, respectively. In addition, pyocyanin pigment synthesis was decreased by 30% and 9.25%, respectively, at sub-MIC doses of 2.5 mg/mL and 1.25 mg/mL. When evaluated at 2.5 mg/mL, the extract did not, however, appreciably affect bacterial growth. Conclusion This study enhances the understanding of antibiotic resistance, alternative treatments, and pathogenic microbes. The in vitro findings suggest that A. deliciosa fruit extract may inhibit pyocyanin production in PAO1. Further research with different formulations is recommended to explore its anti-biofilm properties and potential pharmacological applications.

Biosynthesis and Extraction of Chlorophyll, Carotenoids, Anthocyanins, and Betalaine In Vivo and In Vitro.

As natural bioactive compounds, plant pigments play crucial roles not only in plant phenotype, growth, development, and adaptation to stress but also hold unique value in biotechnology, healthcare, and industrial applications. There is growing interest in the biosynthesis and acquisition of plant pigments. Thus, this paper explores emerging extraction methods of natural pigments and elucidates the biosynthesis pathways of four key plant pigments, chlorophylls, carotenoids, anthocyanins, and betalaine in vivo and in vitro. We comprehensively discuss the application of solvent, supercritical fluid [extraction], ultrasonic, and microwave-assisted extraction techniques, as well as introducing key enzymes, precursors, and synthetic pathways involved in pigment synthesis. δ-Aminolevulinic acid represents a pivotal initiating enzyme for chlorophyll synthesis, whereas isopentenylpyrophosphate, (IPP) and dimethylallyl pyrophosphate, (DMAPP) are closely associated with carotenoid biosynthesis. Phenylalanine and tyrosine are critical substances for anthocyanin and betalaine synthesis, respectively. Hence, crucial genes such as chlI, crtB, PGT8, CYP76AD1, and BvDODA can be employed for heterologous biosynthesis in vitro to meet the demand for increased plant pigment amount. As a pivotal determinant of plant coloration, an in-depth exploration into the high-quality acquisition of plant pigments can provide a basis for developing superior pigments and offer new insights into increasing pigment yield.

Development of Yein-Early, a Unique Fruit-Color and Leaf-Shape Mutant of Citrus unshiu, and Its Specific Selection Marker.

Citrus unshiu Marc. cv. Miyagawa-wase is one of the most widely cultivated citrus varieties on Jeju Island in Republic of Korea. Mutation breeding is a useful tool for inducing genetic diversity by causing genomic mutations in a short period of time. We previously conducted mutation breeding using gamma irradiation to develop new varieties of C. unshiu. Here, we describe one of these varieties, Yein-early, which has a redder peel, greater hardness, and higher sugar content compared with the wild type (WT). Yein-early leaves also showed a unique phenotype compared with the WT, characterized by longer longitudinal length, shorter transverse length, stronger curling, and longer petiole length. Genome resequencing of Yein-early and the WT uncovered significant single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels). These variations were crucial in identifying molecular markers unique to Yein-early. In addition, we developed an allele-specific PCR marker specifically targeting a homozygous SNP in Yein-early that distinguishes it from the WT and other citrus varieties. This study contributes to the understanding of pigment synthesis in fruits and provides a valuable tool for selection of the novel Yein-early variety in citrus breeding programs.

Functional variations in efficiency of PSII during leaf ontogeny in the tropical plant Saraca asoca

Leaf ontogeny of tropical evergreen tree species lasts several months with changes in size, shape, colouration and internal tissue distribution of leaves. Leaf initiation in Saraca asoca generally occurs once in a year during February–April, followed by very limited leafing thereafter. We measured the rate of photosynthesis, chlorophyll a fluorescence, energy quenching and PSII functions during the leaf ontogeny process. Observations were taken up to 35 days after opening of lamina (DAOL). Significant increase in the synthesis and accumulation of photosynthetic pigments but negative net photosynthesis was noticed during initial days of the ontogeny. The leaf moved from heterotrophy to autotrophy with gradual improvement of PSII functions. The ratio of intercellular CO2 (Ci) and ambient CO2 (Ca) showed significant change at ≥11 DAOL. Increase in the age of the leaf (between 5 and 28 DAOL) caused decrease in O-J rise and corresponding increase in J-I and I-P rise as well as of fluorescence maximum (FM) of the OJIP curve. The improvement of the electron transport components of the donor side of PSII was seen with increase in the functional oxygen evolving complex. The functional improvements of the donor and acceptor side of PSII during leaf ontogeny are discussed.

Acptp2,3 participates in the regulation of spore production, stress response, and pigments synthesis in Aspergillus cirstatus.

Aspergillus cristatus was a filamentous fungus that produced sexual spores under hypotonic stress and asexual spores under hypertonic stress. It could be useful for understanding filamentous fungi's sporulation mechanism. Previously, we conducted functional studies on Achog1, which regulated the hyperosmotic glycerol signaling (HOG) pathway and found that SI65_02513 was significantly downregulated in the transcriptomics data of ΔAchog1 knockout strain. This gene was located at multiple locations in the HOG pathway, indicating that it might play an important role in the HOG pathway of A. cristatus. Furthermore, the function of this gene had not been identified in Aspergillus fungi, necessitating further investigation. This gene's conserved domain study revealed that it has the same protein tyrosine phosphatases (PTPs) functional domain as Saccharomyces cerevisiae, hence SI65_02513 was named Acptp2,3. The function of this gene was mostly validated using gene knockout and gene complementation approaches. Knockout strains exhibited sexual and asexual development, as well as pigments synthesis. Morphological observations of the knockout strain were carried out under several stress conditions (osmotic stress, oxidative stress, Congo Red, and sodium dodecyl sulfate (SDS). Real-time fluorescence polymerase chain reaction (PCR) identified the expression of genes involved in sporulation, stress response, and pigments synthesis. The deletion of Acptp2,3 reduced sexual and asexual spore production by 4.4 and 4.6 times, demonstrating that Acptp2,3 positively regulated the sporulation of A. cristatus. The sensitivity tests to osmotic stress revealed that ΔAcptp2,3 strains did not respond to sorbitol-induced osmotic stress. However, ΔAcptp2.3 strains grew considerably slower than the wild type in high concentration sucrose medium. The ΔAcptp2,3 strains grew slower than the wild type on media containing hydrogen peroxide, Congo red, and SDS. These findings showed that Acptp2,3 favorably controlled osmotic stress, oxidative stress, and cell wall-damaging chemical stress in A. cristatus. Deleting Acptp2,3 resulted in a deeper colony color, demonstrating that Apctp2,3 regulated pigment synthesis in A. cistatus. The expression levels of numerous stress-and pigments-related genes matched the phenotypic data. According to our findings, Acptp2,3 played an important role in the regulation of sporulation, stress response, and pigments synthesis in A. cristatus. This was the first study on the function of PTPs in Aspergillus fungi.

Hermetic effect of Moringa oleifera leaf extract mitigates salinity stress in maize by modulating photosynthetic efficiency, and antioxidant activities

Salinity poses a significant constraint to cereal productivity particularly in arid and semiarid regions. The application of allelochemical has shown promising results in mitigating the intensity of abiotic stresses. A pot experiment was conducted to assess the efficacy of different concentrations of aqueous allelopathic extract derived from moringa leaves in mitigating the adverse impacts of salinity on the germination and growth of maize cultivars via seed priming. The study involved three variables: two cultivars of maize, ‘Pioneer 30Y87’ (salt tolerant) and ‘Pioneer 30T60’ (salt sensitive) e seed priming with moringa leaf extract (MLE) at varying concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, and hydro-priming as control; and different salinity levels of 0, 6, and 12 dS m-1. Salinity had a negative impact on the germination process, leading to delayed and suboptimal growth of seedlings. Additionally, salinity reduced the synthesis of photosynthetic pigments (20-50%), photosynthesis, transpiration, internal carbon, and stomatal conductance. Further, MLE also improved the antioxidant activities (catalase: CAT and peroxidase: POD) by 22-56% which reduced the hydrogen peroxide production. Moreover, ‘P-30Y87’ exhibited favorable performance in terms of better germination, growth, photosynthesis and antioxidant activities. The application of moringa leaf extract (3%) resulted in a more notable hermetic effect in elevating salinity stress thereby enhancing germination, growth, photosynthesis and antioxidant activities. In the conclusion, application of MLE (3%) is a promising approach to mitigate the adverse impacts of salinity by improving germination, growth, photosynthesis and antioxidant activities.

High near-infrared reflectance Zn1-xMnxO yellow pigment prepared and properties by co-precipitation method

A successful synthesis of yellow pigments, namely Zn1-xMnxO (x = 0.001–0.009), was achieved using the co-precipitation method. To characterize the prepared pigments, various analytical techniques were employed, including powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric-differential scanning calorimetry (TG-DSC). The results showed that the Zn1-xMnxO series pigments prepared by co-precipitation method retained the ZnO fibrous zincite structure and all had a good yellow color (b*=30.14–40.56) and high NIR solar reflectance (80.66 %-87.80 %). The results of the simulated heat shielding experiments confirmed that the Zn0.997Mn0.003O (abbreviated as ZM3) pigment synthesized in the study was 5°C cooler than the commercial iron yellow pigment, and the thermal imaging experiments showed that the surface temperature of the sample coatings was reduced by 8°C, which further confirmed that the ZM3 pigment had good heat shielding properties. Furthermore, the pigment demonstrates excellent chemical and thermal stability. and can be used as a cold pigment in architectural coatings to obtain energy-saving effects, which has great potential for development.

Benzophenone-4 inhibition in marine diatoms: Physiological and molecular perspectives

Benzophenone-4 (BP-4), a widely utilized organic ultraviolet (UV) filter, is recognized as a pseudo-persistent contaminant in aquatic environments. To elucidate the effects and mechanisms of BP-4 on marine diatoms, an investigation was conducted on the growth rate, photosynthetic pigment content, photosynthetic parameters, antioxidant enzyme activity, malondialdehyde (MDA) levels, cellular structure, and transcriptome profile of the model species, Phaeodactylum tricornutum. The results showed a pronounced inhibition of algal growth upon exposure to BP-4, with a 144 h-EC50 value of 201 mg·L−1. In addition, BP-4 exposure resulted in a significant reduction in biomass, disruption of cell membrane integrity, and increased MDA accumulation, with levels escalating 3.57-fold at 125 mg·L−1 of BP-4. In the BP-4-treated samples, 1556 differentially expressed genes (DEGs) were identified, of which 985 were upregulated and 571 were downregulated. Gene ontology and KEGG pathway enrichment analysis revealed that the carbon fixation and carbon metabolism processes in P. tricornatum were disrupted in response to BP-4 exposure, along with excessive reactive oxygen species (ROS) production. The upregulation of genes associated with photosynthetic pigment (chlorophyll and carotenoids) synthesis, phospholipid synthesis, ribosome biogenesis, and translation-related pathways may be regarded as a component of P. tricornatum's tolerance mechanism towards BP-4. These results provide preliminary insights into the toxicity and tolerance mechanisms of BP-4 on P. tricornatum. They will contribute to a better understanding of the ecotoxicological impacts of BP-4 on the marine ecosystem and provide valuable information for elimination of BP-4 in aquatic environment by bioremediation.