Bisphenol-A incite dose-dependent dissimilitude in the growth pattern, physiology, oxidative status, and metabolite profile of Azolla filiculoides

Anabaena azollae - The cyanobacterial partner of Azolla filiculoides reciprocates variably to dose- and duration-dependent Bisphenol-A exposure

Bisphenol A (BPA) is one of the most studied endocrine-disrupting chemicals (EDC), for its large-scale production and disposal, and ubiquitous presence in the environment. It is also known to impart significant phytotoxic effects on almost all aquatic flora including cyanobacteria. Yet, there are limited studies on the responses of symbiotic cyanobacteria i.e. Anabaena azollae - residing inside Azolla filiculoides. In this context, this study aimed to investigate the response of A. azollae upon exposure to different doses and durations of BPA, which marks this as one of the first such studies. Morphological study reaffirmed the infiltration of BPA through the host's physical barrier and induced various anomalies like filament fragmentation, and cellular disruption especially heterocysts in the case of the higher doses of BPA (20, and 30 mg L-1). Additionally, exposure to higher doses further stimulated the antioxidative enzymes, secondary metabolites and stress/defence markers. However, the exaggerated ROS production (nearly 190%-230% O2.- and 557%-783% H2O2) at 30 mg L-1 severely disrupted the membrane integrity, osmotic balance, and reduced essential biomolecules like sugars, proteins and lipid accumulation. Moreover, higher doses of BPA treatment compromised photosynthetic activity by reducing the photosynthetic pigments and phycobiliproteins (PBPs). Conversely, up to the dose of 10 mg L-1, better cellular integrity, improved accumulation of biomolecules, pigments, and ROS detoxification denoted the neutral/positive effect on the symbionts. The lower doses (≥10 mg L-1) also showed positive indications like higher accumulation of biomolecules proteins (16%-30%), lipids (9%-49%), sugar (18%-52%), and pigments like phycobiliproteins (6%-97%), phycocyanins (6%-134%), which seemed to support the biomass of cyanobionts. Moreover, the said doses stimulated the accumulation of phenolics (98%-117%), flavonoids (159%-224%), and released polysaccharides (60%-183%) alongside stress markers like ascorbate and proline indicating the evocation of defense strategy against BPA stress.

Unveiling the role of cadaverine in mitigating salinity and/or Bisphenol A toxicity in tomato plants and reduced Bisphenol A accumulation in tomato roots

Mitigating the co-existence of environmental stresses on crop plants necessitates the development of integrated, eco-friendly, and sustainable approaches to alleviate plant stress responses. This study represents the first attempt to mitigate the toxic impact of prevalent pollutant (salinity) and an emergent plastic manufacturing pollutants (bisphenol A, BPA) using the polyamine (cadaverine).Tomato plants, treated with or without cadaverine, were subjected to NaCl salinity (120 mM), BPA (375 mg kg-1 soil), and their combinations compared to non-stressed control plants examining morphological, physiological, metabolic, and molecular responses. After 10 days of transplanting, tomato plants under combined stress were unable to survive without cadaverine application. However, cadaverine spraying mitigated the damaging effects of both single and combined stresses under short- and long-term exposure, enabling stressed plants to endure the conditions and complete their life cycles. Cadaverine efficiently restrained the reduction in chlorophylls, carotenoids, and cytosolutes under applied stresses compared to the stressed plants. Cadaverine also increased α-tocopherol content (by 171 and 53 %) and enhanced the activity of polyphenol oxidase (by 26 and 32 %), glutathione s-transferases (by 18 and 39 %), superoxide dismutase (by 23 and 46 %), and phenylalanine ammonia-lyase (by 9 and 25 %), under BPA and salinity stress, respectively. Thus, cadaverine ameliorated the oxidative and nitrosative burst induced by BPA or salinity, respectively by declining hydroxyl radical (by 28 % and 20 %), superoxide anion (by 73 % and 74 %), nitric oxide (by 60 and 65 %), lipid peroxidation (by 35 % and 54 %), and lipoxygenase activity (by 74 and 68 %). Moreover, cadaverine enhanced the expression of defence-related genes, including polyphenol oxidase, tubulin, and thaumatin-like protein, and reduced the uptake of BPA in the tomato's roots while promoting its metabolism in leaves and fruits. This ensured the safety of the harvested fruits. By mitigating stress, improving plant resilience, and limiting pollutant accumulation, cadaverine presents significant potential for sustainable agricultural practices and food safety. These findings offer valuable insights into the role of cadaverine in managing abiotic stress and safeguarding crop health in environmentally challenging conditions.

Occurrence of bisphenol A analogues in the aquatic environment and their behaviors and toxicity effects in plants

Continuous technological and economic development has led to the extensive use of bisphenol A analogues (BPs) in products, leading to their release to aquatic environments and posing threats to aquatic plants. However, few papers have systemically reviewed the interactions between BPs and aquatic plants. This review comprehensively summarizes the properties, occurrence, fate, and hazardous influences of BPs on aquatic plants. BPs have been widely detected in the global aquatic environment, with concentrations generally ranging from a lower range of ng/L or ng/g to an upper range of μg/L or μg/g in surface water, groundwater, seawater, and sediments. Aquatic plants effectively uptake and translocate BPs, and metabolize them into new compounds. Meanwhile, BPs exposures have diverse toxic effects on the growth, photosynthesis, antioxidant, phytohormones, and structural integrity of aquatic plants. High-throughput omics assays provide significant evidence showing how BPs disturb gene transcription, proteins, and metabolism in plants. This review highlights the need for increased attention on the effects of emerging BPA alternatives, joint treatment, long-term exposure with environmental relevant doses, and potential hazards posed by ingesting polluted plants.

Mechanism of up-regulated H2O2 BPA-derived production and production of (poly)phenols by two seaweeds of the genus Ulva

The present study provides information on the effects of BPA on ROS production-related phenomena in the chlorophytes Ulva rigida and U. intestinalis, and on the mechanism they establish against BPA toxicity, at environmentally relevant concentrations (0.1-3 μg L-1). Up-regulated H2O2 generation seems to be a key factor causing oxidative damage. Interspecific differences, in terms of the mechanism and the temporal response to BPA toxicity were observed. BPA effects on U. rigida were more intense and appeared earlier (on 1D at 0.1 μg L-1) compared to U. intestinalis and mostly after 7D (LOEC: 0.3 μg L-1, Terminal time, Tt: 7D). In U. rigida, on 1-5D, the 'mosaic' type effect patterns ('models' 3A/3B) with 'unaffected' and 'affected' areas (dark content, positive H2DCF-DA staining signal/H2O2 production and chlorophyll autofluorescence signal loss) indicated a time-dependent manner. After 7D, only U. rigida cells with dark content formed aggregates, showing positive H2O2 production ('model' 4) or in some cells oxidative damages triggering retrograde signaling in the neighboring 'unaffected' areas ('model' 5). H2O2 overproduction (CTCF ratio) in U. rigida, on 1D at the lowest concentration and after 7D at 0.3-1/3 μg L-1, respectively, seems to stimulate (poly)phenolic production, in a dose- and time-dependent manner. U. intestinalis did not display severe BPA impact (i.e., 'models' 4, 5) at any exposures, although at a later time indicated a lower LOEC (0.1 μg L-1, Tt: 9D) than that in U. rigida. In U. intestinalis, H2O2 production does not appear to stimulate high (poly)phenolic amounts.

Metabolome profile variation in Azolla filiculoides exposed to Bisphenol A assists in the identification of stress-responsive metabolites

This study attempted to explore the metabolome profile of Azolla filiculoides subjected to two different concentrations of BPA (1 and 30 mg L-1) in congruence with two different durations (3 and 9 days) of treatment. Bisphenol A (BPA) is a ubiquitously occurring environmental pollutant that imparts acute toxicity in aquatic plants. Therefore, studying the variations in the fern metabolome profile and identifying stress-responsive metabolites can help develop criteria for assessing the aquatic ecosystem. In recent times, metabolomics has drawn attention for its ability to detect biochemical processes and help link plant responses with environmental stresses. However, the studies concerning the metabolome profile of A. filiculoides exposed to environmental contaminants are limited. In the present study, the untargeted metabolomics study allowed the detection of a large array of metabolites, with 767 shared metabolites representing 41 crucial pathways. Exposure to 30 mg L-1 BPA seemingly disrupted the primary metabolism of the fern and induced a shift toward defense-related pathways. Additionally, BPA stress triggered the expression of metabolites like 3,4-dihydroxyphenylglycol, perillic acid, and perillaldehyde in BPA_L3 (1 mg L-1 for 3 days) and BPA_L9 (1 mg L-1 for 9 days) samples indicating protective mechanism of the plants. Conversely, the BPA_H3 (30 mg L-1 for 3 days) and BPA_H9 (30 mg L-1 for 9 days) samples expressed a distinct set of markers like luteolin, 3-hydroxyanthranilic acid, cinnamaldehyde, and l-DOPA indicating the onset of senescence and apoptosis related pathways can help in the health assessment of freshwater ecosystems and also appraisal of ecotoxicological risks imposed by BPA.

Toxicity of bisphenol A and p-nitrophenol on tomato plants: Morpho-physiological, ionomic profile, and antioxidants/defense-related gene expression studies

Bisphenol A (BPA) and p-nitrophenol (PNP) are emerging contaminants of soils due to their wide presence in agricultural and industrial products. Thus, the present study aimed to integrate morpho-physiological, ionic homeostasis, and defense- and antioxidant-related genes in the response of tomato plants to BPA or PNP stress, an area of research that has been scarcely studied. In this work, increasing the levels of BPA and PNP in the soil intensified their drastic effects on the biomass and photosynthetic pigments of tomato plants. Moreover, BPA and PNP induced osmotic stress on tomato plants by reducing soluble sugars and soluble proteins relative to control. The soil contamination with BPA and PNP treatments caused a decline in the levels of macro- and micro-elements in the foliar tissues of tomatoes while simultaneously increasing the contents of non-essential micronutrients. The Fourier transform infrared analysis of the active components in tomato leaves revealed that BPA influenced the presence of certain functional groups, resulting in the absence of some functional groups, while on PNP treatment, there was a shift observed in certain functional groups compared to the control. At the molecular level, BPA and PNP induced an increase in the gene expression of polyphenol oxidase and peroxidase, with the exception of POD gene expression under BPA stress. The expression of the thaumatin-like protein gene increased at the highest level of PNP and a moderate level of BPA without any significant effect of both pollutants on the expression of the tubulin (TUB) gene. The comprehensive analysis of biochemical responses in tomato plants subjected to BPA and PNP stress illustrates valuable insights into the mechanisms underlying tolerance to these pollutants.

Toxicity of bisphenol A (BPA) and its analogues BPF and BPS on the free-floating macrophyte Salvinia biloba

Evidence linking the toxicity of bisphenol A (BPA) to environmental and public-health issues has led to restrictions on its use. This compound has been gradually replaced with analogues proposed as a safer alternative, normally bisphenol F (BPF) and bisphenol S (BPS), but these substitutes are structurally almost identical to BPA, suggesting they may pose similar risks. The effects of BPA and these analogues were compared for antioxidant activity, lipid peroxidation, free-radical generation, photosynthetic pigments, and chlorophyll fluorescence in Salvinia biloba Raddi (S. biloba) plants exposed to environmentally relevant and sublethal concentrations (1, 10, 50, 100 and 150 μM). Bisphenol exposure promoted alterations in most of the physiological parameters investigated, with BPS toxicity differing slightly from that of the analogues. Furthermore, S. biloba removed similar levels of BPA and BPF from aqueous solutions with ≈70% removed at the 150 μM concentration, while BPS was less effectively removed, with only 23% removed at 150 μM. These findings show that high concentrations of bisphenols (10≥) are toxic to S. biloba, and even typical environmental levels (≤1 μM) can induce metabolic changes in plants, bringing to light that both BPA and its substitutes BPF and BPS pose risks to aquatic ecosystems.

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Impacts of bisphenol A on growth and reproductive traits of submerged macrophyte Vallisneria natans

Bisphenol A (BPA) is considered a contaminant of emerging concern and interferes with the normal activities of living organisms. The toxicity of BPA is evident in animals and terrestrial plants. However, the response of aquatic plants to low BPA concentrations is still unclear. In the present study, effects of varying BPA loadings (targeting at 0.01, 0.1, and 1 mg/L) on the growth and reproductive traits of the dioecious annual submerged macrophyte Vallisneria natans were assessed through a 5-month experiment. The results showed that BPA inhibited the elongation of V. natans leaves but resulted in an increase in leaf number and ramet number under the highest BPA loading treatment (targeting at 1 mg/L). In addition, detectable biochemical changes in the total carbon and soluble sugar contents were found, which both were significantly higher at the highest BPA loading treatment. However, the total biomass did not alter significantly after the BPA treatments, indicating that BPA did not induce direct toxic effects on the growth of V. natans. At the highest BPA loading treatment, female individuals of V. natans allocated less number for ramet than male ones, showing a clear sexual dimorphism. No significant differences between the five treatments were found for the flower or fruit traits, while the germination rate was significantly inhibited for the seeds collected from the highest BPA loading treatment. In conclusion, V. natans tolerated low concentrations of BPA by making a trade-off between ramet (leaf) number and leaf elongation, as well as modulating the total carbon and soluble sugar contents. However, serious consequence of decline in seed viability implied that the impact of BPA on plant reproduction were usually underestimated.