Research progress on differentiation and regulation of plant chromoplasts.

Carotenoids, natural tetraterpenoids found abundantly in plants, contribute to the diverse colors of plant non-photosynthetic tissues and provide fragrance through their cleavage products, which also play crucial roles in plant growth and development. Understanding the synthesis, degradation, and storage pathways of carotenoids and identifying regulatory factors represents a significant strategy for enhancing plant quality. Chromoplasts serve as the primary plastids responsible for carotenoid accumulation, and their differentiation is linked to the levels of carotenoids, rendering them a subject of substantial research interest. The differentiation of chromoplasts involves alterations in plastid structure and protein import machinery. Additionally, this process is influenced by factors such as the ORANGE (OR) gene, Clp proteases, xanthophyll esterification, and environmental factors. This review shows the relationship between chromoplast and carotenoid accumulation by presenting recent advances in chromoplast structure, the differentiation process, and key regulatory factors, which can also provide a reference for rational exploitation of chromoplasts to enhance plant quality.

Genome-wide analysis and identification of Carotenoid Cleavage Oxygenase (CCO) gene family in coffee (coffee arabica) under abiotic stress.

The coffee industry holds importance, providing livelihoods for millions of farmers globally and playing a vital role in the economies of coffee-producing countries. Environmental conditions such as drought and temperature fluctuations can adversely affect the quality and yield of coffee crops.Carotenoid cleavage oxygenases (CCO) enzymes are essential for coffee plants as they help break down carotenoids contributing to growth and stress resistance. However, knowledge about the CCO gene family in Coffee arabica was limited. In this study identified 21 CCO genes in Coffee arabica (C. arabica) revealing two subfamilies carotenoid cleavage dioxygenases (CCDs) and 9-cis-epoxy carotenoid dioxygenases (NCED) through phylogenic analysis. These subfamilies exhibited distribution patterns in terms of gene structure, domains, and motifs. The 21 CaCCO genes, comprising 5 NCED and 16 CCD genes were found across chromosomes. Promoter sequencing analysis revealed cis-elements that likely interact with plant stress-responsive, growth-related, and phytohormones, like auxin and abscisic acid. A comprehensive genome-wide comparison, between C. arabica and A. thaliana was conducted to understand the characteristics of CCO genes. RTqPCR data indicated that CaNCED5, CaNCED6, CaNCED12, and CaNCED20 are target genes involved in the growth of drought coffee plants leading to increased crop yield, in a conditions, with limited water availability. This reveals the role of coffee CCOs in responding to abiotic stress and identifies potential genes useful for breeding stress-resistant coffee varieties.

Omnivore and vegetarians show similar body composition and skin physiology across body regions-A comparative analysis.

BACKGROUND: Skin physiology seems to be influenced by dietary choices and body composition, although links between these factors remain poorly characterised. In the present manuscript, we elaborate on the potential relationships among food groups, body composition and skin physiology in omnivores and vegetarians. MATERIAL AND METHODS: This cross-sectional observational study involved 181 participants, 129 omnivores and 52 vegetarians. The main functions of the skin measured in our laboratory were transepidermal water loss, deep and superficial epidermal hydration, skin elasticity, and carotenoid content. Skin variables obtained from different body regions were made comparable by a new Proportional Skin Index calculated to respect their relative representativity. RESULTS: No statistical differences were found when comparing both groups' body composition and skin variables from different body regions, with the exception of the skin carotenoid content significantly higher in the vegetarian group (p < 0.001). CONCLUSION: Although dietary patterns significantly differed between groups, with vegetarians consuming fewer animal-derived products and more plant-based foods, multiple linear regression analysis revealed no differences or association between the dietary pattern and the skin physiology. These findings highlight the need for further research to elucidate the specific impact of diet and food groups and body composition on skin physiology.

Physiological, transcriptomic and metabolomic insights of three extremophyte woody species living in the multi-stress environment of the Atacama Desert.

MAIN CONCLUSIONS: In contrast to Neltuma species, S. tamarugo exhibited higher stress tolerance, maintaining photosynthetic performance through enhanced gene expression and metabolites. Differentially accumulated metabolites include chlorophyll and carotenoids and accumulation of non-nitrogen osmoprotectants. Plant species have developed different adaptive strategies to live under extreme environmental conditions. Hypothetically, extremophyte species present a unique configuration of physiological functions that prioritize stress-tolerance mechanisms while carefully managing resource allocation for photosynthesis. This could be particularly challenging under a multi-stress environment, where the synthesis of multiple and sequential molecular mechanisms is induced. We explored this hypothesis in three phylogenetically related woody species co-occurring in the Atacama Desert, Strombocarpa tamarugo, Neltuma alba, and Neltuma chilensis, by analyzing their leaf dehydration and freezing tolerance and by characterizing their photosynthetic performance under natural growth conditions. Besides, the transcriptomic profiling, biochemical analyses of leaf pigments, and metabolite analysis by untargeted metabolomics were conducted to study gene expression and metabolomic landscape within this challenging multi-stress environment. S. tamarugo showed a higher photosynthetic capacity and leaf stress tolerance than the other species. In this species, a multifactorial response was observed, which involves high photochemical activity associated with a higher content of chlorophylls and ß-carotene. The oxidative damage of the photosynthetic apparatus is probably attenuated by the synthesis of complex antioxidant molecules in the three species, but S. tamarugo showed the highest antioxidant capacity. Comparative transcriptomic and metabolomic analyses among the species showed the differential expression of genes involved in the biosynthetic pathways of key stress-related metabolites. Moreover, the synthesis of non-nitrogen osmoprotectant molecules, such as ciceritol and mannitol in S. tamarugo, would allow the nitrogen allocation to support its high photosynthetic capacity without compromising leaf dehydration tolerance and freezing stress avoidance.

Traditional and new trend strategies to enhance pigment contents in microalgae.

Microalgae are a source of a wide variety of commodities, including particularly valuable pigments. The typical pigments present in microalgae are the chlorophylls, carotenoids, and phycobiliproteins. However, other types of pigments, of the family of water-soluble polyphenols, usually encountered in terrestrial plants, have been recently reported in microalgae. Among such microalgal polyphenols, many flavonoids have a yellowish hue, and are used as natural textile dyes. Besides being used as natural colorants, for example in the food or cosmetic industry, microalgal pigments also possess many bioactive properties, making them functional as nutraceutical or pharmaceutical agents. Each type of pigment, with its own chemical structure, fulfills particular biological functions. Considering both eukaryotes and prokaryotes, some species within the four most promising microalgae groups (Cyanobacteria, Rhodophyta, Chlorophyta and Heterokontophyta) are distinguished by their high contents of specific added-value pigments. To further enhance microalgae pigment contents during autotrophic cultivation, a review is made of the main related strategies adopted during the last decade, including light adjustments (quantity and quality, and the duration of the photoperiod cycle), and regard to mineral medium characteristics (salinity, nutrients concentrations, presence of inductive chemicals). In contrast to what is usually observed for growth-related pigments, accumulation of non-photosynthetic pigments (polyphenols and secondary carotenoids) requires particularly stressful conditions. Finally, pigment enrichment is also made possible with two new cutting-edge technologies, via the application of metallic nanoparticles or magnetic fields.

Pigments from pathogenic bacteria: a comprehensive update on recent advances.

Bacterial pigments stand out as exceptional natural bioactive compounds with versatile functionalities. The pigments represent molecules from distinct chemical categories including terpenes, terpenoids, carotenoids, pyridine, pyrrole, indole, and phenazines, which are synthesized by diverse groups of bacteria. Their spectrum of physiological activities encompasses bioactive potentials that often confer fitness advantages to facilitate the survival of bacteria amid challenging environmental conditions. A large proportion of such pigments are produced by bacterial pathogens mostly as secondary metabolites. Their multifaceted properties augment potential applications in biomedical, food, pharmaceutical, textile, paint industries, bioremediation, and in biosensor development. Apart from possessing a less detrimental impact on health with environmentally beneficial attributes, tractable and scalable production strategies render bacterial pigments a sustainable option for novel biotechnological exploration for untapped discoveries. The review offers a comprehensive account of physiological role of pigments from bacterial pathogens, production strategies, and potential applications in various biomedical and biotechnological fields. Alongside, the prospect of combining bacterial pigment research with cutting-edge approaches like nanotechnology has been discussed to highlight future endeavours.

Characterization of carotenoids extracted from Haloferax larsenii NCIM 5678 isolated from Pachpadra salt lake, Rajasthan.

Carotenoids are a diverse group of pigments known for their broad range of biological functions and applications. This study delves into multifaceted potential of carotenoids extracted from Haloferax larsenii NCIM 5678 previously isolated from Pachpadra Salt Lake in Rajasthan, India. H. larsenii NCIM 5678 was able to grow up to OD600 1.77 ± 0.03 with carotenoid concentration, 3.3 ± 0.03 µg/ml. The spectrophotometric analysis of carotenoid extract indicated the presence of three-fingered peak (460, 490 and 520 nm) which is a characteristic feature of bacterioruberin and its derivatives. The bacterioruberin was purified using silica gel column chromatography and thin layer chromatography. The carotenoid extract showed 12.3 ± 0.09 mm zone of growth inhibition with a minimum inhibitory concentration 546 ng/ml against indicator strain, H. larsenii HA4. The percentage antioxidant activity of carotenoid was found to be 84% which was higher as compared to commercially available ascorbic acid (56.74%). Thus, carotenoid extract from H. larsenii NCIM 5678 possesses unique attributes with compelling evidence of antimicrobial and antioxidant potential for the development of novel pharmaceuticals and nutraceuticals.

Iodine enriched kale (Brassica oleracea var. sabellica L.)-The influence of heat treatments on its iodine content, basic composition and antioxidative properties.

Iodine deficiency in the diet globally continues to be a cause of many diseases and disabilities. Kale is a vegetable that has health-promoting potential because of many nutrients and bioactive compounds (ascorbic acid, carotenoids, glucosinolates and phenolic compounds). Brassica vegetables, including kale, have been strongly recommended as dietary adjuvants for improving health. The nutrient and health-promoting compounds in kale are significantly affected by thermal treatments. Changes in phytochemicals upon such activities may result from two contrary phenomena: breakdown of nutrients and bioactive compounds and a matrix softening effect, which increases the extractability of phytochemicals, which may be especially significant in the case of iodine-fortified kale. This study investigated changes of basic composition, iodine, vitamin C, total carotenoids and polyphenols contents as well as antioxidant activity caused by steaming, blanching and boiling processes in the levels of two cultivars of kale (green and red) non-biofortified and biofortified via the application to nutrient solutions in hydroponic of two iodoquinolines [8-hydroxy-7-iodo-5-quinolinesulfonic acid (8-OH-7-I-5QSA) and 5-chloro-7-iodo-8-quinoline (5-Cl-7-I-8-Q)] and KIO3. Thermal processes generally significantly reduced the content of the components in question and the antioxidant activity of kale, regardless of cultivar and enrichment. It was observed that the red cultivar of kale had a greater ability to accumulate and reduce iodine losses during the culinary processes. 8-hydroxy-7-iodo-5-quinolinesulfonic acid showed a protective effect against the treatments used, compared to other enrichments, thus contributing to the preservation of high iodine content.

Assessment of the Cu phytoremediation potential of Chrysanthemum indicum L. and Tagetes erecta L. using analysis of growth and physiological characteristics.

In the current study, the Cu phytoremediation ability of two ornamental plants, Chrysanthemum indicum L. and Tagetes erecta L., was tracked concerning the growth and physiological responses. Plants were subjected to varying concentrations of Cu (0, 100, 200, and 400 mg/kg) under the pot experiment for 8 weeks. The results showed that the measured growth and physiological characteristics declined in T. erecta shoots and roots at all tested treatments compared with the control. However, in C. indicum at 100 mg/kg, shoot biomass, shoot total soluble protein, and leaves number remained equal to that of the control and then reduced by rising Cu concentrations, compared with the control. Also, results indicated that in C. indicum, after 56 days of exposure to Cu, the chlorophyll pigments content markedly increased and reached a maximum level at 100 mg/kg dose and gradually declined with enhancing Cu concentrations, compared with the control. Other measured growth and physiological parameters decreased in both tissues of C. indicum in response to Cu usage in the growth medium. The carotenoid content of T. erecta decreased in all studied Cu levels in comparison to the control, but in C. indicum remained unaffected up to 200 mg/kg Cu in comparison to the control and then enhanced with increasing Cu level. The augmentation of antioxidant enzyme activity in two species, especially in roots, reflected the incident of Cu stress as demonstrated by elevated MDA and ion leakage levels. Data concerning copper accumulation in tissues, TF, and BAF showed T. erecta is a weak Cu accumulator and seems not to be an appropriate candidate for Cu phytoremediation. However, the Cu content in shoots and roots of C. indicum increased significantly with an increment in applied Cu level. Also, C. indicum accumulated higher Cu concentrations in the roots than in shoots and exhibited TF < 1, 0.1 < BAF root < 1, and can be considered as a Cu excluder by the phytostabilization mechanism.

Effect of pectin structure on the in vitro bioaccessibility of carotenoids in simulated juice model.

The impact of pectin structure on carotenoid bioaccessibility is still uncertain. This study aims to investigate how the different pectic polymers affected the bioaccessibility of carotenoids in a simulated juice model during static in vitro digestion. This study includes homogalacturonan (HG), which is a linear pectic polymer, rhamnogalacturonan-I (RG-I), which is a branched pectic polymer, and rhamnogalacturonan (RG), which is a diverse pectic polymer rich in RG-I, rhamnogalacturonan-II (RG-II), and xylogalacturonan domains. Juice models without pectin had the highest carotenoid bioaccessibility, suggesting pectin has negative effects on carotenoid bioaccessibility. During the intestinal phase, systems with HG showed the highest viscosity, followed by systems with RG and systems with RG-I. Systems with RG-I had lower carotenoid bioaccessibility than systems with HG and RG-II. Both the percentage of RG-I and the average side chain length of RG-I had negative correlations with carotenoid bioaccessibility. RG-I side chains with more arabinose and/or galactose might cause lower carotenoid bioaccessibility in this juice model system. This study offers valuable insights into the relationship between pectin structure and carotenoid bioaccessibility in a simulated juice model, highlighting the importance of considering pectin composition for maximizing carotenoid bioaccessibility and potential health benefits in fruit-based beverages.

Functional Characterization of the First Bona Fide Phytoene Synthase in Red Algae from Pyropia yezoensis.

The formation of phytoene by condensing two geranylgeranyl diphosphate molecules catalyzed by phytoene synthase (PSY) is the first committed and rate-limiting step in carotenoid biosynthesis, which has been extensively investigated in bacteria, land plants and microalgae. However, this step in macroalgae remains unknown. In the present study, a gene encoding putative phytoene synthase was cloned from the economic red alga Pyropia yezoensis-a species that has long been used in food and pharmaceuticals. The conservative motifs/domains and the tertiary structure predicted using bioinformatic tools suggested that the cloned PyPSY should encode a phytoene synthase; this was empirically confirmed by pigment complementation in E. coli. This phytoene synthase was encoded by a single copy gene, whose expression was presumably regulated by many factors. The phylogenetic relationship of PSYs from different organisms suggested that red algae are probably the progeny of primary endosymbiosis and plastid donors of secondary endosymbiosis.

Mitigation of salinity stress in yarrow (Achillea millefolium L.) plants through spermidine application.

This study investigated the mitigating effects of spermidine on salinity-stressed yarrow plants (Achillea millefolium L.), an economically important medicinal crop. Plants were treated with four salinity levels (0, 30, 60, 90 mM NaCl) and three spermidine concentrations (0, 1.5, 3 µM). Salinity induced electrolyte leakage in a dose-dependent manner, increasing from 22% at 30 mM to 56% at 90 mM NaCl without spermidine. However, 1.5 µM spermidine significantly reduced leakage across salinities by 1.35-11.2% relative to untreated stressed plants. Photosynthetic pigments (chlorophyll a, b, carotenoids) also exhibited salinity- and spermidine-modulated responses. While salinity decreased chlorophyll a, both spermidine concentrations increased chlorophyll b and carotenoids under most saline conditions. Salinity and spermidine synergistically elevated osmoprotectants proline and total carbohydrates, with 3 µM spermidine augmenting proline and carbohydrates up to 14.4% and 13.1% at 90 mM NaCl, respectively. Antioxidant enzymes CAT, POD and APX displayed complex regulation influenced by treatment factors. Moreover, salinity stress and spermidine also influenced the expression of linalool and pinene synthetase genes, with the highest expression levels observed under 90 mM salt stress and the application of 3 µM spermidine. The findings provide valuable insights into the responses of yarrow plants to salinity stress and highlight the potential of spermidine in mitigating the adverse effects of salinity stress.

Integrative Analysis of Metabolome and Transcriptome of Carotenoid Biosynthesis Reveals the Mechanism of Fruit Color Change in Tomato (Solanum lycopersicum).

Tomato fruit ripening is accompanied by carotenoid accumulation and color changes. To elucidate the regulatory mechanisms underlying carotenoid synthesis during fruit ripening, a combined transcriptomic and metabolomic analysis was conducted on red-fruited tomato (WP190) and orange-fruited tomato (ZH108). A total of twenty-nine (29) different carotenoid compounds were identified in tomato fruits at six different stages. The abundance of the majority of the carotenoids was enhanced significantly with fruit ripening, with higher levels of lycopene; (E/Z)-lycopene; and α-, ß- and γ-carotenoids detected in the fruits of WP190 at 50 and 60 days post anthesis (DPA). Transcriptome analysis revealed that the fruits of two varieties exhibited the highest number of differentially expressed genes (DEGs) at 50 DPA, and a module of co-expressed genes related to the fruit carotenoid content was established by WGCNA. qRT-PCR analysis validated the transcriptome result with a significantly elevated transcript level of lycopene biosynthesis genes (including SlPSY2, SlZCIS, SlPDS, SlZDS and SlCRTSO2) observed in WP190 at 50 DPA in comparison to ZH108. In addition, during the ripening process, the expression of ethylene biosynthesis (SlACSs and SlACOs) and signaling (SlEIN3 and SlERF1) genes was also increased, and these mechanisms may regulate carotenoid accumulation and fruit ripening in tomato. Differential expression of several key genes in the fruit of two tomato varieties at different stages regulates the accumulation of carotenoids and leads to differences in color between the two varieties of tomato. The results of this study provide a comprehensive understanding of carotenoid accumulation and ethylene biosynthesis and signal transduction pathway regulatory mechanisms during tomato fruit development.

The impact of polystyrene nanoplastics (PSNPs) on physiological and biochemical parameters of the microalgae Spirulina platensis.

Nanoplastics, as emerging pollutants, have harmful effects on living organisms and the environment, the mechanisms and extent of which remain unclear. Microalgae, as one of the most important biological groups in the food chain and sensitive environmental indicators to various pollutants, are considered a suitable option for investigating the effects of nanoplastics. In this study, the effects of polystyrene nanoplastics on the growth rate, dry weight, chlorophyll a and carotenoid levels, proline, and lipid peroxidation in the Spirulina platensis were examined. Three concentrations of 0.1, 1, and 10 mg L-1 of PSNPs were used alongside a control sample with zero concentration, with four repetitions in one-liter containers for 20 days under optimal temperature and light conditions. Various analyses, including growth rate, dry weight, proline, chlorophyll a and carotenoid levels, and lipid peroxidation, were performed. The results indicated that exposure to PSNP stress led to a significant decrease in growth rate, dry weight, and chlorophyll a and carotenoid levels compared to the control sample. Furthermore, this stress increased the levels of proline and lipid peroxidation in Spirulina platensis. Morphological analysis via microscopy supported these findings, indicating considerable environmental risks associated with PSNPs.

Ultrastructural changes, pigment responses and bioaccumulation in the microalga Phaeodactylum tricornutum Bohlin exposed to BPA analogues.

As well-known, microalgae have a pivotal role in aquatic environments, being the primary producer. In this study, we investigated the effects of Bisphenol A (BPA) analogues on cell ultrastructure, reactive oxygen species (ROS) production and photosynthetic pigment responses in the diatom Phaeodactylum tricornutum. Microalgae were exposed during both exponential and stationary growth phases to an environmental relevant concentration (300 ng/L) of three differing BPA analogues (BPAF, BPF, and BPS) and their mixture (100 ng/L of each compound). Bioaccumulation of such compounds in microalgae was also analysed. During the stationary growth phase, a significant increase in the percentage of cells with hydrogen peroxide production was recorded after exposure to both BPS and MIX. Conversely, no significant effects on total chlorophylls and carotenoids were observed. During exponential growth phase we observed that control cultures had chloroplasts with well-organized thylakoid membranes and a central pyrenoid. On the contrary, the culture cells treated with BPA analogues and MIX showed chloroplasts characterized by evident dilation of thylakoid membranes. The presence of degeneration areas in the cytoplasm was also recorded. During the stationary growth phase, control and culture cells were characterized by chloroplasts with a regular thylakoid system, whereas BPA analogues-exposed cells were characterized by a deep degradation of the cytoplasm but showed chloroplasts without evident alterations of the thylakoid system. Lipid bodies were visible in treated microalgae. Lastly, microalgae bioaccumulated mainly BPS and BPF, alone or in the MIX. Overall, results obtained revealed that BPA analogues can affect some important biochemical and ultrastructure features of microalgae, promoting ROS production. Lastly, the capability of microalgae to bioaccumulate bisphenols suggest a potential ecotoxicological risk for filter-feeders organisms.

Study on the photosynthetic growth characters in Cimicifuga dahurica (Turcz.) Maxim under different supplemental light environments.

Cimicifuga dahurica (C. dahurica) is an important medicinal plant in the northern region of China. The best supplemental light environment helps plant growth, development, and metabolism. In this study, we used two-year-old seedlings as experimental materials. The white light as the control (CK). The different ratios of red (R) and blue (B) combined light were supplemented (T1, 2R: 1B, 255.37 µmol m-2·s-1; T2, 3R: 1B, 279.69 µmol m-2·s-1; T3, 7R: 1B, 211.16 µmol m-2·s-1). The growth characteristics, photosynthetic pigment content, photosynthesis and chlorophyll fluorescence parameters, and primary metabolite content were studied in seedlings. The results showed that: 1) The fresh weight from shoot, root, and total fresh weight were significantly (P < 0.05) increased under T2 and T3 treatment. 2) The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll (Chl) were significantly (P < 0.05) increased under T2 treatment, and carotenoid (car) content was reduced. 3) The photochemical quenching (qP), the actual photosynthetic efficiency of PSII (Y(II)), and the photosynthetic electron transfer rate (ETR) from leaves were significantly (P < 0.05) increased under T1 treatment. The Net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) were significantly (P < 0.05) increased under T2 and T3 treatments. 4) A total of 52 primary metabolites were detected in C. dahurica leaves. Compared with CK, 14, 15, and 18 differential metabolites were screened under T1, T2, and T3 treatments. In addition, D-xylose, D-glucose, glycerol, glycolic acid, and succinic acid were significantly (P < 0.05) accumulated under the T2 treatment, which could regulate the TCA cycle metabolism pathway. The correlation analysis suggested that plant growth was promoted by regulating the change of D-mannose content in galactinol metabolism and amino sugar and nucleotide sugar metabolism. In summary, the growth of C. dahurica was improved under T2 treatment.

Role of silicon in alleviating boron toxicity and enhancing growth and physiological traits in hydroponically cultivated Zea mays var. Merit.

BACKGROUND: Boron (B) is a micronutrient, but excessive levels can cause phytotoxicity, impaired growth, and reduced photosynthesis. B toxicity arises from over-fertilization, high soil B levels, or irrigation with B-rich water. Conversely, silicon (Si) is recognized as an element that mitigates stress and alleviates the toxic effects of certain nutrients. In this study, to evaluate the effect of different concentrations of Si on maize under boron stress conditions, a factorial experiment based on a randomized complete block design was conducted with three replications in a hydroponic system. The experiment utilized a nutrient solution for maize var. Merit that contained three different boron (B) concentrations (0.5, 2, and 4 mg L-1) and three Si concentrations (0, 28, and 56 mg L-1). RESULTS: Our findings unveiled that exogenous application of B resulted in a substantial escalation of B concentration in maize leaves. Furthermore, B exposure elicited a significant diminution in fresh and dry plant biomass, chlorophyll index, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids, and membrane stability index (MSI). As the B concentration augmented, malondialdehyde (MDA) content and catalase (CAT) enzyme activity exhibited a concomitant increment. Conversely, the supplementation of Si facilitated an amelioration in plant fresh and dry weight, total carbohydrate, and total soluble protein. Moreover, the elevated activity of antioxidant enzymes culminated in a decrement in hydrogen peroxide (H2O2) and MDA content. In addition, the combined influence of Si and B had a statistically significant impact on the leaf chlorophyll index, total chlorophyll (a + b) content, Si and B accumulation levels, as well as the enzymatic activities of guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and H2O2 levels. These unique findings indicated the detrimental impact of B toxicity on various physiological and biochemical attributes of maize, while highlighting the potential of Si supplementation in mitigating the deleterious effects through modulation of antioxidant machinery and biomolecule synthesis. CONCLUSIONS: This study highlights the potential of Si supplementation in alleviating the deleterious effects of B toxicity in maize. Increased Si consumption mitigated chlorophyll degradation under B toxicity, but it also caused a significant reduction in the concentrations of essential micronutrients iron (Fe), copper (Cu), and zinc (Zn). While Si supplementation shows promise in counteracting B toxicity, the observed decrease in Fe, Cu, and Zn concentrations warrants further investigation to optimize this approach and maintain overall plant nutritional status.

Recent advances in lycopene and germacrene a biosynthesis and their role as antineoplastic drugs.

Sesquiterpenes and tetraterpenes are classes of plant-derived natural products with antineoplastic effects. While plant extraction of the sesquiterpene, germacrene A, and the tetraterpene, lycopene suffers supply chain deficits and poor yields, chemical synthesis has difficulties in separating stereoisomers. This review highlights cutting-edge developments in producing germacrene A and lycopene from microbial cell factories. We then summarize the antineoplastic properties of ß-elemene (a thermal product from germacrene A), sesquiterpene lactones (metabolic products from germacrene A), and lycopene. We also elaborate on strategies to optimize microbial-based germacrene A and lycopene production.

Targeted metabolomics revealed the seasonal plasticity of skin color and pigment metabolites in ornamental koi carp.

The koi carp is an ornamental fish that was obtained through artificial selection from the common carp (Cyprinus carpio L.). The most economically important traits of koi are their beautiful skin patterns in bright colors. As seasonality is an important factor in the biology and ecology of fish, we thus assumed that seasonal changes are involved in regulating the formation of skin color and patterns of koi carp. The white, red, cyan, and black skin colors from four varieties of scaleless koi carp (Doitsu Shiromuji (W), Doitsu Kohaku (WR), Doitsu Showa Sanke (WRI), and Kumonryu (WI)) were evaluated using the CIELab color space (lightness, redness, and yellowness) in different seasons. Compared to winter, the yellowness of the white color in all koi varieties decreased in summer and autumn. The black skin color areas in WRI and WI koi increased in summer and autumn compared to winter. The yellowness of the red color decreased only in WRI koi, while no changes were observed in WR koi. Targeted metabolomics analysis revealed that the levels of the structural pigment guanine of all koi varieties showed significant seasonal variation. Of seven detected carotenoids, the zeaxanthin and tunaxanthin contents in W, WI, and WRI koi changed with the seasons, while none of the carotenoids in WR koi were altered. Of the seven potential regulatory metabolites, epinephrine, melatonin, and cyclic adenosine monophosphate (cAMP) in all four koi varieties showed the highest levels in winter. A correlation analysis suggested that the seasonal changes in white skin color occurred through the epinephrine-cAMP pathway; melanin-dependent and carotenoid-dependent skin color changes occurred through melatonin in koi carp. This study demonstrated the seasonal plasticity of skin color in koi carp regulated by melatonin and epinephrine, associating with variety and color specificity.

Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch.

The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultraviolet-exposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce less common carotenoids and a cluster of photosynthetic genes. This cluster appears to originate from a potentially new species of the Rhodobacteraceae family. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as beta-carotene and beta-cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria-produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water.