Spartinivicinus poritis sp. nov., a red pigment-producing bacterium isolated from a scleractinian coral Porites lutea.

A Gram-stain-negative, red pigment-producing, aerobic, and rod-shaped bacterial strain (A2-2T) was isolated from a bleached scleractinian coral (Porites lutea). Strain A2-2T grew with 1.0-7.0 % (w/v) NaCl (optimum, 3.0 %), at pH 6.0-11.0 (optimum, pH 8.0), and at 18-41 °C (optimum, 35 °C). Results of phylogenetic analysis based on 16S rRNA gene sequences suggested that strain A2-2T fell within the genus Spartinivicinus and was closely related to Spartinivicinus ruber S2-4-1HT (98.1 % sequence similarity) and Spartinivicinus marinus SM1973T (98.0 % sequence similarity). The predominant cellular fatty acids of strain A2-2T were C16 : 0 (31.0 %), summed feature 3 (29.0 %), summed feature 8 (11.7 %), C12 : 0 3-OH (6.4 %), and C10 : 0 3-OH (5.5 %), while the major respiratory quinone was Q-9. The polar lipids mainly comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified phospholipid. The genome size of strain A2-2T was 6.8 Mb, with a G+C content of 40.2 mol%. The DNA-DNA hybridization value was 24.2 % between A2-2T and S. ruber S2-4-1HT and 36.9 % between A2-2T and S. marinus SM1973T, while the average nucleotide identity values were 80.1 and 88.8 %, respectively. Based on these findings, strain A2-2T could be recognized to represent a novel species of the genus Spartinivicinus, for which the name Spartinivicinus poritis sp. nov. is proposed. The type strain is A2-2T (=MCCC 1K08228T=KCTC 8323T).

The Use of Insect Pigment in Art Works.

In this compilation, the focus is on the Cochineal insect (Dactylopius coccus Costa, 1835 (Hemiptera: Dactylopiidae)), a creature native to South America that produces a potent natural red pigment known as "carmine". This pigment, utilized for obtaining the color red, has been an integral part of the art world for thousands of years. Indigenous cultures, in particular, have employed the dye extracted from this insect in the creation of textile dyes and paintings. Moreover, the Cochineal insect and its unique pigments have not only supported artistic expression but also captivated and inspired artists. During the Renaissance period, artists preferred the carmine pigment produced by the females of the Cochineal insect for obtaining bright and vivid red tones. This study delves into the history of the Cochineal insect, its role in art, and its perception in the modern world. Famous paintings created with dyes obtained from the Cochineal insect are discussed, exploring how pigments have found a place in the art world and how artists have utilized this extraordinary source to create distinctive works.

Control of Optical Reflection in Ca2MgWO6 by Co and Mo Doping.

To develop novel inorganic red pigments without harmful elements, we focused on the band structure of Ca2(Mg, Co)WO6 and attempted to narrow its bandgap by replacing the W6+ sites in the host structure of Mo6+. Ca2Mg1-xCoxW1-yMoyO6 (0.10 ≤ x ≤ 0.30; 0.45 ≤ y ≤ 0.60) samples were synthesized by a sol-gel method using citric acids, and the crystal structure, optical properties, and color of the samples were characterized. The Ca2Mg1-xCoxW1-yMoyO6 solid solution was successfully formed, which absorbed visible light at wavelengths below 600 nm. In addition, the absorption wavelength shifted to longer wavelengths with increasing Mo6+ content. This is because a new conduction band composed of a Co3d-W5d-Mo4d hybrid orbital was formed by Mo6+ doping to reduce the bandgap energy. Thus, the color of the samples gradually changed from pale orange to dark red, with a hue angle (h°) of less than 35°. Based on the above results, the optical absorption wavelength of the Ca2Mg1-xCoxW1-yMoyO6 system can be controlled to change the color by adjusting the bandgap energy.

Improved Generation, Physicochemical Characteristics, and Food Application Studies of a Red Colorant Obtained from Oxidative Coupling of Chlorogenic Acid and Tryptophan.

Due to a widespread consumer reluctance toward synthetic food dyes, the interest in natural compounds from plants has increased. This study aimed to optimize the oxidation process between chlorogenic acid (CQA) and tryptophan (Trp) using sodium periodate (NaIO4) to obtain a red-colored pigment. The impact of temperature and different ratios of Trp to NaIO4 on the reaction progress was investigated. After the best conditions for the reaction were established, three pH values were tested. The reaction time could be reduced from 72 to 24 h with a yield of 46 ± 2% w/w based on the quantity of CQA. After the first purification step of the product by size exclusion chromatography, the pigment obtained was characterized for its solubility, and its hydrolyzed form was used for investigations into the stability at different pH values, storage under light and in the dark (period of 28 days), in the presence of reducing agents, and for heat resistance. Finally, several food matrices were successfully colored with the natural pigment in amounts from 0.005 to 0.01% (w/w). In conclusion, the present study provides new insights into the feasible production and comprehensive characterization of a red pigment derived from oxidative coupling of CQA and Trp, as well as its application in food systems.

Expanding the Toolbox for Genetic Manipulation in Pseudogymnoascus: RNAi-Mediated Silencing and CRISPR/Cas9-Mediated Disruption of a Polyketide Synthase Gene Involved in Red Pigment Production in P. verrucosus.

Fungi belonging to the genus Pseudogymnoascus have garnered increasing attention in recent years. One of the members of the genus, P. destructans, has been identified as the causal agent of a severe bat disease. Simultaneously, the knowledge of Pseudogymnoascus species has expanded, in parallel with the increased availability of genome sequences. Moreover, Pseudogymnoascus exhibits great potential as a producer of specialized metabolites, displaying a diverse array of biological activities. Despite these significant advancements, the genetic landscape of Pseudogymnoascus remains largely unexplored due to the scarcity of suitable molecular tools for genetic manipulation. In this study, we successfully implemented RNAi-mediated gene silencing and CRISPR/Cas9-mediated disruption in Pseudogymnoascus, using an Antarctic strain of Pseudogymnoascus verrucosus as a model. Both methods were applied to target azpA, a gene involved in red pigment biosynthesis. Silencing of the azpA gene to levels of 90% or higher eliminated red pigment production, resulting in transformants exhibiting a white phenotype. On the other hand, the CRISPR/Cas9 system led to a high percentage (73%) of transformants with a one-nucleotide insertion, thereby inactivating azpA and abolishing red pigment production, resulting in a white phenotype. The successful application of RNAi-mediated gene silencing and CRISPR/Cas9-mediated disruption represents a significant advancement in Pseudogymnoascus research, opening avenues for comprehensive functional genetic investigations within this underexplored fungal genus.

Differences in the Chromogenic Effect of Corn Starch and Potato Starch on Paprika Red Pigment and Structural Characterisation.

The present study aims to investigate the chromogenic effect and the interaction between starch-pigment complexes of corn starch (CS) and potato starch (PS) complexed with paprika red pigment. Compared to PS, CS showed 12.5 times higher adsorption capacity for paprika red pigment. Additionally, the a* value of CS-P (26.90 ± 0.23) was significantly higher than that of PS-P (22.45 ± 1.84), resulting in a corn starch-paprika red pigment complex (CS-P) with a more intense red colour. The addition of paprika red pigment significantly decreased the particle size and porosity of CS by 48.14 ± 5.29% and 17.01 ± 3.80%, respectively. Conversely, no significant impact on PS was observed. Additionally, the Fourier transform infrared (FT-IR) spectroscopy results revealed that the starch molecules and paprika red pigment were bound to each other through strong hydrogen bonds. X-diffraction (XRD) results indicated that the starch-paprika red pigment complexes have a V-shaped structure. Furthermore, the relative crystallinity of the complexes between starch and red pepper pigment showed an increasing trend, however, the relative crystallinity of CS increased significantly by 11.77 ± 0.99-49.21 ± 3.67%. Consequently, the CS-P colouring was good.

Preparation of Hybrid Nanopigments with Excellent Environmental Stability, Antibacterial and Antioxidant Properties Based on Monascus Red and Sepiolite by One-Step Grinding Process.

This study is focused on the preparation, characterization, and multifunctional properties of intelligent hybrid nanopigments. The hybrid nanopigments with excellent environmental stability and antibacterial and antioxidant properties were fabricated based on natural Monascus red, surfactant, and sepiolite via a facile one-step grinding process. The density functional theory calculations demonstrated that the surfactants loaded on sepiolite were in favor of enhancing the electrostatic, coordination, and hydrogen bonding interactions between Monascus red and sepiolite. Thus, the obtained hybrid nanopigments exhibited excellent antibacterial and antioxidant properties, with an inhibition effect on Gram-positive bacteria that was superior to that of Gram-negative bacteria. In addition, the scavenging activity on DPPH and hydroxyl free radicals as well as the reducing power of hybrid nanopigments were higher than those of hybrid nanopigments prepared without the addition of the surfactant. Inspired by nature, gas-sensitive reversible alochroic superamphiphobic coatings with excellent thermal and chemical stability were successfully designed by combining hybrid nanopigments and fluorinated polysiloxane. Therefore, intelligent multifunctional hybrid nanopigments have great application foreground in related fields.

Characterization of insecticidal metabolite oosporein in Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno, a geographically distinct isolate from Kerala, India.

Lecanicillium saksenae, an indigenous isolate from Kerala, India is a potent entomopathogen against hemipteran pests. The wine-red pigmentation produced by this isolate distinguishes it from many other isolates of L. saksenae reported across the globe. This study, therefore, sought to isolate and characterize the pigment molecule. The wine-red pigment extracted through liquid - liquid partition of the fungal culture was subjected to structural characterization and identification through UV spectrometry, Fourier Transform Infrared Spectrometry (FTIR), High Resolution Liquid Chromatography, Mass Spectrometry (HR-LCMS) and Nuclear Magnetic Resonance Spectrometry (NMR). It was unambiguously identified as a dibenzoquinone compound, oosporein, a known bioactive insecticidal metabolite. The empirical formula of which was confirmed as C14H10O8 and molecular weight, m/z 306.22. The dose dependent bioefficacy of oosporein with 1000 ppm at 96 h recorded a mortality of 60.25 per cent in nymphs of brinjal mealybug, Coccidohystrix insolita, while it was still lower (51.00%) in adults. In this study, we could identify that L. saksenae reported from Kerala, India was geographically distinct. Sequence analysis based on 18srDNA and phylogenetic analysis confirmed the species identity of this indigenous isolate with that of L. saksenae documented in NCBI. This finding paves the way for the possibilities of tapping the potential of bioactive metabolites for pest management and uplifting the species as a potent bioagent in insect pest management programmes.

Efficient acquisition of high-purity cyanidin-3-O-glucoside from mulberry fruits: An integrated process of ATPS whole-cell transformation and semi-preparative HPLC purification.

As a nutritious fruit, mulberry is an ideal source of high-quality cyanidin-3-O-glucoside (C3G) with various biological activities. However, the difficult separation process of high-purity C3G leads to its high price. To rapidly prepare high-purity C3G, cyanidin-3-O-rutinoside is converted to C3G by direct hydrolysis of rhamnose bond using a whole-cell catalyst containing α-rhamnosidase. Combined with an aqueous two-phase system, a coupling reaction separation system was established. Two monomers were successfully separated by semi-preparative high performance liquid chromatography (semi-preparative HPLC). The conversion of C3G catalyzed by whole-cells in the PEG/Na2SO4 system increased from 47.11 % to 66.56 %, compared with the EtOH/(NH4)2SO4 system, and the whole-cell activity remained above 50 % after five rounds of reuse. Meanwhile, the purity of C3G was increased to 99 % via the semi-preparative HPLC purification and identified by MS. Thus, an integrated process of whole-cell-catalyzed conversion and product peak cutting partition collection provides a novel strategy for efficient biomanufacturing of high-purity C3G.

The flashy red color of the red velvet mite Balaustium murorum (Prostigmata: Erythraeidae) is caused by high abundance of the keto-carotenoids, astaxanthin and 3-hydroxyechinenone.

The red velvet mite, Balaustium murorum (Hermann), is a pollenophagous free-living mite with a flashy red body. This mite occurs in early spring and lives on sunny surfaces of human-made structures, such as concrete. Hence, it is inevitably exposed to a harsh environment due to solar ultraviolet-B (UV-B) radiation and radiant heat, which cause oxidative stress via the production of reactive oxygen species. The spider mite Panonychus citri that resides on upper leaf surfaces accumulates synthesized keto-carotenoids to protect against oxidative stress. Therefore, we evaluated carotenoid composition in the red pigment of B. murorum. To identify major carotenoids, we performed a high-performance liquid chromatography analysis of intact and de-esterified pigments of B. murorum females. The flashy red pigments of B. murorum consisted of the highly abundant keto-carotenoids astaxanthin and 3-hydroxyechinenone (60 and 38% of major carotenoids, respectively), and a small amount of ß-carotene (2%). Although P. citri is an astaxanthin-rich species, the astaxanthin concentration (per protein) in B. murorum is 127-fold that in P. citri. Due to their high antioxidant activities, those keto-carotenoids probably contribute to the survival of B. murorum in the harsh environment caused by solar UV-B radiation and radiant heat in inorganic habitats.

Biosynthesis and polyketide oxidation of Monascus red pigments in an integrated fermentation system with microparticles and surfactants.

Monascus red pigments are widely used in the food industry, mainly as intracellular red pigments. The low yields of extracellular red pigments (ERPs) make them unsuitable for large-scale industrial production. Herein, a novel integrated fermentation system (IFS) consisting of sodium starch octenyl succinate and Triton X-100 was explored for increasing yield, resulting in an ERP yield of 126.7 U/mL, 82.6% higher production than controls (69.4 U/mL). Major ERP components in control fermentations were monascopyridine A and monascopyridine B, but dehydro derivatives, rubropunctamine and monascorubramine, predominated in the test fermentations, presumably due to polyketide oxidation induced by Triton X-100. Improvement of hyphal morphology, membrane permeability, respiratory activity, and gene expression for red pigment biosynthesis is likely to be critical to increase yield and change the compositions. This study provides an effective strategy to accelerate the biosynthesis and secretion of Monascus pigments.

A local Talaromyces atroroseus TRP-NRC isolate: isolation, genetic improvement, and biotechnological approach combined with LC/HRESI-MS characterization, skin safety, and wool fabric dyeing ability of the produced red pigment mixture.

BACKGROUND: During the last decade, enormous research efforts have been directed at identifying potent microorganisms as sustainable green cell factories for eco-friendly pigments. Talaromyces atroroseus has recently been shown to excrete large amounts of azaphilone mycotoxin-free red pigment mixture comprising some known coloring components together with many uncharacterized metabolites. In this study, a new Talaromyces atroroseus isolate was identified via sequencing of the fragment of the nuclear ribosomal gene cluster containing internal transcribed spacers and 5.8S rRNA gene. The parameters that affected the level of pigment production were optimized in uncommon static conditions of culture and genetic improvement, via γ-irradiation, to improve pigment yield. Moreover, chemical characterization using LC/MS and skin safety test of the target pigment mixture were precisely conducted to maximize its benefits as a natural and safe red pigment for wool fabrics. RESULTS: Molecular identification via the sequencing of the ITS of the rDNA encoding gene cluster revealed that the fungal isolate TRP-NRC was T. atroroseus TRP-NRC (deposited in GenBank under accession number MW282329). In the static conditions of culture, pigment production was dramatically enhanced to 27.36 g/L in an optimum yeast malt peptone medium of 2% mannitol at pH 2-4.5 and 30 °C for 7 days of incubation. Under exposure to a 400-Gy γ-radiation dose, pigment yield was increased to a 3-fold level higher than that recorded for the wild type. Based on the inter-simple sequence repeats (ISSR), as a molecular marker tool, the wild-type T. atroroseus TRP-NRC strain and its mutants were discriminated. The UHPLC/HRESI-MS analytical tool characterized 60 metabolites, including many unknown molecules, at appropriate concentrations. It is worthy to note that four mitorubrin derivatives were identified for the first time in T. atroroseus, i.e., mitorubrinolamine acetate, dihydro-PP-O, mitorobrinal, and mitorubrinol. The range of irritation indexes (0-0.1) demonstrated an adequate skin safety after the direct local application of the pigment mixture. Finally, the pigment mixture exhibited a remarkably good dyeing ability in wool fabrics, with high-fastness properties. CONCLUSIONS: Because of its sustainable and economic production, the target red pigment mixture may be applied in the future in textile, food, cosmetics, or different pharmaceutical industries after extensive conventional safety and toxicity studies, which are currently under consideration.

Yeast red pigment, protein aggregates, and amyloidoses: a review.

Estimating the amyloid level in yeast Saccharomyces, we found out that the red pigment (product of polymerization of aminoimidazole ribotide) accumulating in ade1 and ade2 mutants leads to drop of the amyloid content. We demonstrated in vitro that fibrils of several proteins grown in the presence of the red pigment stop formation at the protofibril stage and form stable aggregates due to coalescence. Also, the red pigment inhibits reactive oxygen species accumulation in cells. This observation suggests that red pigment is involved in oxidative stress response. We developed an approach to identify the proteins whose aggregation state depends on prion (amyloid) or red pigment presence. These sets of proteins overlap and in both cases involve many different chaperones. Red pigment binds amyloids and is supposed to prevent chaperone-mediated prion propagation. An original yeast-Drosophila model was offered to estimate the red pigment effect on human proteins involved in neurodegeneration. As yeast cells are a natural feed of Drosophila, we could compare the data on transgenic flies fed on red and white yeast cells. Red pigment inhibits aggregation of human Amyloid beta and α-synuclein expressed in yeast cells. In the brain of transgenic flies, the red pigment diminishes amyloid beta level and the area of neurodegeneration. An improvement in memory and viability accompanied these changes. In transgenic flies expressing human α-synuclein, the pigment leads to a decreased death rate of dopaminergic neurons and improves mobility. The obtained results demonstrate yeast red pigment potential for the treatment of neurodegenerative diseases.

Transposon insertion mutation of Antarctic psychrotrophic fungus for red pigment production adaptive to normal temperature.

Polar regions are rich in microbial and product resources. Geomyces sp. WNF-15A is an Antarctic psy chrotrophic filamentous fungus producing high quality red pigment with potential for industrial use. However, efficient biosynthesis of red pigment can only realize at low temperature, which brings difficult control and high cost for the large-scale fermentation. This study aims to develop transposon insertion mutation method to improve cell growth and red pigment production adaptive to normal temperature. Genetic manipulation system of this fungus was firstly developed by antibiotic marker screening, protoplast preparation and transformation optimization, by which transformation efficiency of ∼50% was finally achieved. Then transposable insertion systems were established using Helitron, Fot1, and Impala transposons. The transposition efficiency reached 11.9%, 9.4%, and 4.6%, respectively. Mutant MP1 achieved the highest red pigment production (OD520 of 39) at 14°C, which was 40% higher than the wild-type strain. Mutant MP14 reached a maximum red pigment production (OD520 of 14.8) at 20°C, which was about twofold of the wild-type strain. Mutants MP2 and MP10 broke the repression mechanism of red pigment biosynthesis in the wild-type and allowed production at 25°C. For cell growth, eight mutants grew remarkably better (12%∼30% biomass higher) than the wild-type at 25°C. This study established an efficient genetic manipulation and transposon insertion mutation platform for polar filamentous fungus. It provides reference for genetic breeding of psychrotrophic fungi from polar and other regions.

Minos and Restless transposon insertion mutagenesis of psychrotrophic fungus for red pigment synthesis adaptive to normal temperature.

The polar psychrotrophic fungus Geomyces sp. WNF-15A can produce high-quality natural red pigment for the potential use as edible pigment. However, it shows low-temperature-dependent synthesis of red pigment, which limits its large-scale industrial applications due to the difficult and high-cost bioprocess control. This study aims to develop transposon-mediated mutagenesis methods to generate mutants that are able to synthesize red pigment at normal temperature. Four transposable systems, including single and dual transposable systems, were established in this fungus based on the Minos from Drosophila hydei and the Restless from Tolypocladium inflatum. A total of 23 production-dominant mutants and 12 growth-dominant mutants were thus obtained by constructed transposable systems. At 14 °C and 20 °C, the MPS1 mutant strain achieved the highest level of red pigment (OD520 of 43.3 and 29.7, respectively), which was increased by 78.4% and 128.7% compared to the wild-type, respectively. Of note, 4 mutants (MPS1, MPS3, MPS4 and MPD1) successfully synthesized red pigment (OD520 of 5.0, 5.3, 4.7 and 4.9, respectively) at 25 °C, which broke the limit of the wild-type production under normal temperature. Generally, the dual transposable systems of Minos and Restless were more efficient than their single transposable systems for mutagenesis in this fungus. However, the positive mutation ratios were similar between the dual and single transposable systems for either Minos or Restless. This study provides alternative tools for genetic mutagenesis breeding of fungi from extreme environments.

Insights into the Activation of a Crustacean G Protein-Coupled Receptor: Evaluation of the Red Pigment-Concentrating Hormone Receptor of the Water Flea Daphnia pulex (Dappu-RPCH R).

The validation of a previously developed model of the interaction between the red pigment-concentrating hormone of Daphnia pulex and its cognate receptor (Jackson et al., IJBM 106, 969-978, 2018) was undertaken. Single amino acid replacements, noticeably an Ala scan, of the ligand, Dappu-RPCH, were docked to the receptor, and the binding energies calculated and compared to the one with Dappu-RPCH. As a second step, the same molecules were docked using molecular dynamics (MD) in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane. Changes in binding energy were compared to previous results on in vitro receptor activation (Marco et al., Sci. Rep. 7, 6851, 2017). Residue scanning and MD simulations both gave comparable results for binding energy. For most mutants, there was a good inverse correlation between in vitro activity and binding. There were, however, exceptions; for example: [Ala4]Dappu-RPCH bound as tightly as the cognate ligand but had little activity. This seeming discrepancy was explained when the MD data were analyzed in detail, showing that, although [Ala4]Dappu-RPCH had multiple interactions with the receptor accounting for the high binding energy, the interacting residues of the receptor were quite different to those of Dappu-RPCH. The MD calculations show clearly that the strong binding affinity of the ligand to the receptor is not sufficient for activation. Interaction of the binding of the ligand to two residues of the receptor, Ser 155 and Gln 237, is also essential. A comparison of our computational results with the experimental results of Marco et al. and comparison with the extensive data on GnRH supports the validity of our Dappu-RPCH R model.

Inducing red pigment and inhibiting citrinin production by adding lanthanum(III) ion in Monascus purpureus fermentation.

Monascus pigments (MPs) are widely used natural colorants in Asian countries. The problems of low extracellular red pigment (ERP) and high citrinin remain to be solved in Monascus pigment production. The effect of lanthanum(III) ion (LaCl3) on Monascus purpureus fermentation was investigated in this study. The yields of ERP and biomass respectively reached maxima of 124.10 U/mL and 33.10 g/L by adding 0.4 g/L La3+ on the second day in the total 8-day fermentation; simultaneously, citrinin was decreased by 59.93% and 38.14% in the extracellular and intracellular fractions, respectively. Reactive oxygen species (ROS) levels were obviously improved by La3+ treatment, while the activities of catalase (CAT) and superoxide dismutase (SOD) were increased compared with the control. The ratio of unsaturated/saturated fatty acids in mycelia was increased from 2.94 to 3.49, indicating that the permeability and fluidity of the cell membrane were enhanced under La3+ treatment. Gene expression analysis showed that the relative expression levels of Monascus pigment synthesis genes (pksPT, mppB, mppD, MpFasB2, and MpPKS5) were significantly upregulated by La3+ treatment, and in contrast, the relative expression levels of citrinin synthesis genes (ctnA, pksCT and mppC) were markedly downregulated. This work confirmed that LaCl3 possesses the potential to induce red pigment biosynthesis and inhibit citrinin production in M. purpureus fermentation. KEY POINTS: • La3+ induced red pigment and inhibited citrinin production in Monascus fermentation. • La3+ regulated genes expression up for Monascus pigment and down for citrinin. • La3+ increased the UFAs in cell membrane to enhance the permeability and fluidity.

Mycosynthesis of novel lactone in foliar endophytic fungus isolated from Bixa orellana L.

There is a colossal demand for natural pigments and its applications in recent times. In the study, a novel lactone pigment was isolated from a predominant endophytic fungus residing in Bixa orellana L. (Bixaceae) leaves. The endophyte was identified as Fusarium verticillioides through morphological and molecular investigations. The optimum growth parameters of the endophyte for pigment production were at 33 ºC with pH 6.5 in dark. Through comprehensive spectroscopic studies, the structure of the isolated lactone was resolved and identified as (E)-3, 3-dimethyl-4-(pent-1-en-1-yl)-4-propyldihydrofuran-2(3H)-one. The acute oral toxicity study of the pigment investigated upon female Wistar rats indicated the median lethal dose (LD50) value above 1000 mg/kg body weight affirming safety. Thus, the red pigment from the isolated endophyte may be employed as a sustainable source for natural colorant in industries owing to its non-toxicity. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-020-02566-x.

Critical effect of iron red pigment on photoaging behavior of polypropylene microplastics in artificial seawater.

Microplastics (MPs) containing chemical additives undergo extensive aging in the environment, but the effect of additives on aging behavior of MPs is not fully understood. This study evaluated the effects of iron red pigment on the photoaging behavior of polypropylene (PP) MPs and the release kinetics of Fe(II) and Fe(III) under simulated sunlight. Based on analyses in surface property and aging products of leachate, the incorporated iron red pigment significantly decreased the photoaging rate of PP MPs. The critical effect mainly depended on the light shielding and the competition of pigment for electrons and reactive oxygen species generated from irradiated MPs. Light irradiation also caused the production of homologous series of organic products containing dicarboxylic acid end groups. Moreover, aging of pigmented MPs enhanced the release of Fe ions in leachates, and the types of released iron ions were different between dark and light conditions, where the iron ion in dark system was mainly as Fe(III), while Fe(II) was the dominant form in light irradiation, since the released Fe(III) reacted with MP-derived organic acids and reactive oxygen species in light condition. The findings highlight the critical role of inorganic pigments in the environmental fate and risk of MPs.

Insights on Molecular Mechanisms of Ovarian Development in Decapod Crustacea: Focus on Vitellogenesis-Stimulating Factors and Pathways.

Vitellogenesis in crustaceans is an energy-consuming process. Though the underlying mechanisms of ovarian maturation in decapod Crustacea are still unclear, evidence indicates the process to be regulated by antagonistically-acting inhibitory and stimulating factors specifically originating from X-organ/sinus gland (XO/SG) complex. Among the reported neuromediators, neuropeptides belonging to the crustacean hyperglycemic hormone (CHH)-family have been studied extensively. The structure and dynamics of inhibitory action of vitellogenesis-inhibiting hormone (VIH) on vitellogenesis have been demonstrated in several species. Similarly, the stimulatory effects of other neuropeptides of the CHH-family on crustacean vitellogenesis have also been validated. Advancement in transcriptomic sequencing and comparative genome analysis has led to the discovery of a large number of neuromediators, peptides, and putative peptide receptors having pleiotropic and novel functions in decapod reproduction. Furthermore, differing research strategies have indicated that neurotransmitters and steroid hormones play an integrative role by stimulating neuropeptide secretion, thus demonstrating the complex intertwining of regulatory factors in reproduction. However, the molecular mechanisms by which the combinatorial effect of eyestalk hormones, neuromediators and other factors coordinate to regulate ovarian maturation remain elusive. These multifunctional substances are speculated to control ovarian maturation possibly via the autocrine/paracrine pathway by acting directly on the gonads or by indirectly exerting their stimulatory effects by triggering the release of a putative gonad stimulating factor from the thoracic ganglion. Acting through receptors, they possibly affect levels of cyclic nucleotides (cAMP and cGMP) and Ca2+ in target tissues leading to the regulation of vitellogenesis. The "stimulatory paradox" effect of eyestalk ablation on ovarian maturation continues to be exploited in commercial aquaculture operations, and is outweighed by the detrimental physiological effects of this procedure. In this regard, the development of efficient alternatives to eyestalk ablation based on scientific knowledge is a necessity. In this article, we focus principally on the signaling pathways of positive neuromediators and other factors regulating crustacean reproduction, providing an overview of their proposed receptor-mediated stimulatory mechanisms, intracellular signaling, and probable interaction with other hormonal signals. Finally, we provide insight into future research directions on crustacean reproduction as well as potential applications of such research to aquaculture technology development.