Environmental Plasticity Research Articles

Strategies for biofilm optimization of plastic-degrading microorganisms and isolating biofilm formers from plastic-contaminated environments

Abstract The perpetual disposal of plastic waste, combined with ineffective waste management strategies, has resulted in widespread environmental plastic pollution. Microbial plastic biodegradation represents an emerging solution to this problem. However, biodegradation studies tend to overlook the fundamental prerequisite of initial surface colonization via biofilm formation. This study had two independent but connected aims relating to plastic surface colonization by microorganisms: to enhance biofilm formation by known plastic degraders, with translational potential for improved plastic degradation, and to isolate microorganisms from microplastic contaminated environments with the ability to colonize plastic surfaces. Planktonic and biofilm responses to diverse carbon and energy sources were investigated over 7 days, using Bacillus subtilis 168, Fusarium solani (Martius) Saccardo, Ideonella sakaiensis 201-F6, Pseudomonas putida KT2440, and Rhodococcus ruber C208. This enabled optimal conditions for biofilm formation by each strain to be determined. In parallel, environmental samples containing synthetic or natural polymeric substances (anaerobic digestate, landfill leachate, and microplastic contaminated compost) were incubated with polyethylene and polyethylene terephthalate films, to isolate microorganisms capable of colonizing their surfaces. This yielded eight bacterial isolates from three genera: Bacillus, Lysinibacillus, and Proteus. These genera contain species that have been shown to degrade plastics and other recalcitrant synthetic polymers, demonstrating the success of our approach. This study also suggests that discrete plastic types may create different ecological niches which can be exploited by unique bacterial colonizers. Our findings underscore the importance of considering plastic colonization by microbial biofilms in the context of their biodegradation.

Assessment of common bean varieties for adaptability and productivity in the forest-steppe conditions of the Priobye

The adaptive ability and productivity of common beans in the conditions of the forest steppe of the Ob region are studied in work. Genetic evaluation of varieties will speed up the breeding work to create forms that combine ecological plasticity and productivity based on exploring the adaptive potential of productivity elements. An urgent task of breeding is to develop varieties with a high stable yield, which can combine high quality, productivity and environmental plasticity in the genotype. Based on the UPH “Michurintsev Garden” of the Novosibirsk State Agrarian University, an assessment was carried out (2015-20) of grain bean varieties of different ecological and geographical origin with a bush type of growth according to the characteristics: the number of beans per plant, the weight of seeds per plant, the weight of 1000 seeds, seed yield. The work aims to evaluate the varieties of common beans for adaptability and productivity in the conditions of the forest steppe of the Ob region. Adaptability was assessed according to the methodology developed by A. V. Kilchevsky and L. V. Khotyleva. According to the “number of beans per plant”, the varieties Rubyn (Sgi = 6,5 %), Stringless (Sgi = 9,9 %), Zolotistaya (Sgi = 14,2 %), Zusha white (Sgi = 17,6 %), Zusha black (Sgi = 18,6 %) are classified as forms with low and medium levels of ecological variability. The Zolotistaya variety has high indicators of the parameters OAСi (4.2) and bi (4.96), the average level of BVGi (2.05) by the weight of seeds from the plant. Based on «1000 seed weight», most varieties are classified as stable – the Sgi value does not exceed 10 %. The genotypes of grain beans combining high yield with environmental resistance of Zusha black and Zolotistaya have been identified. Veenoorl, Zolotistaya, Brunot, and Rubyn samples are recommended for inclusion in breeding programs to create new adapted varieties of common beans.

Effect of depth-absorbed dose distribution on the flexural modulus of carbon fiber–reinforced plastics in a radiation environment in radio-astronomical satellite orbit

Carbon fiber–reinforced polymers (CFRP) are used as structural materials for spacecraft due to their excellent physical properties. However, exposure in space to environmental factors, such as radiation, ultraviolet radiation, and thermal cycling, would alter these properties. Therefore, in order to ensure the safety and reliability of the spacecraft and the feasibility of the mission, it is necessary to evaluate the material’s space-environment resistance.The space environment consists of various types of energy and radiation, resulting in a non-uniform depth-absorbed dose distribution. This means that the absorbed dose is significantly higher at the surface of the material and lower with depth. However, reproducing this distribution in a ground-based test facility that typically uses a single energy irradiation is challenging. To overcome this challenge in ground-based testing, it is recommended that multiple radiation types and energies be irradiated to simulate the depth-absorbed dose distribution in a real space environment. However, there is a lack of understanding about the agreement between the depth-absorbed dose distribution obtained in real space environments and in ground-simulated tests. Additionally, the degree to which each depth region of the absorbed dose distribution affects material degradation is unknown. Hence, a faithful reproduction of the depth-absorbed dose distribution in a real space environment requires not only massive test facilities with significant financial investment but also a significant amount of time spent on irradiating those materials containing radiation that have practically no effect on material degradation.This study focused on analyzing the changes in the mechanical properties of CFRP due to radiation degradation using composite beam theory and mathematical models while considering the non-uniform depth-absorbed dose distribution in real space environments. The results of this study provide insight into which depth region of the depth-absorbed dose distribution is dominant for radiation-induced changes in mechanical properties when the CFRP plate thickness varies.

Can plastic pollution drive the emergence and dissemination of novel zoonotic diseases?

As the volume of plastic in the environment increases, so too does human interactions with plastic pollution. Similarly, domestic, feral, and wild animals are increasingly interacting with plastic pollution, highlighting the potential for contamination of plastic wastes with animal faeces, urine, saliva, and blood. Substantial evidence indicates that once in the environment, plastics rapidly become colonised by microbial biofilm (the so-called ‘plastisphere), which often includes potentially harmful microbial pathogens (including pathogens that are zoonotic in nature). Climate change, increased urbanisation, and the intensification of agriculture, mean that the three-way interactions between humans, animals, and plastic pollution are becoming more frequent, which is significant as almost 60% of emerging human infectious diseases during the last century have been zoonotic. Here, we critically review the potential for contaminated environmental plastics to facilitate the evolution of novel pathogenic strains of microorganisms, and the subsequent role of plastic pollution in the cyclical dissemination of zoonotic pathogens. As the interactions between humans, animals, and plastic pollution continues to grow, and the volume of plastics entering the environment increases, there is clearly an urgent need to better understand the role of plastic waste in facilitating zoonotic pathogen evolution and dissemination, and the effect this can have on environmental and human health.

Humidity-Induced Protein-Based Artificial Synaptic Devices for Neuroprosthetic Applications.

Neuroprosthetics and brain-machine interfaces are immensely beneficial for people with neurological disabilities, and the future generation of neural repair systems will utilize neuromorphic devices for the advantages of energy efficiency and real-time performance abilities. Conventional synaptic devices are not compatible to work in such conditions. The cerebrospinal fluid (CSF) in the central part of the nervous system is composed of 99% water. Therefore, artificial synaptic devices, which are the fundamental component of neuromorphic devices, should resemble biological nerves while being biocompatible, and functional in high-humidity environments with higher functional stability for real-time applications in the human body. In this work, artificial synaptic devices are fabricated based on gelatin-PEDOT: PSScomposite as an active material to work more effectively in a highly humid environment (≈90% relative humidity). These devices successfully mimic various synaptic properties by the continuous variation of conductance, like, excitatory/inhibitory post-synaptic current(EPSC/IPSC), paired-pulse facilitation/depression(PPF/PPD), spike-voltage dependent plasticity (SVDP), spike-duration dependent plasticity (SDDP), and spike-rate dependent plasticity (SRDP) in environments at a relative humidity levels of ≈90%.

Erosion of rigid plastics in turbid (sandy) water: quantitative assessment for marine environments and formation of microplastics.

Mechanical degradation (erosion) of plastics in the marine environment has been reported in many literature studies but without quantitative information. This type of degradation is crucial as it accounts for most of the initial microplastic products, in marine environments (e.g., rivers and oceans). Here, we quantify the erosion of plastics by water-borne sediments under typical perpendicular water velocities and sand loads of turbid rivers and coastal oceans. Polypropylene (PP) shows the highest response to water-borne erosion, with a surface degradation rate of 5160 μm per year (4.44 mg per mm2 per year), compared with high-density polyethylene (HDPE) with a degradation rate of 1874 μm per year (1.79 mg per mm2 per year), resulting in the formation of microplastics (MPs). The rate of formation of such microplastic particles (>10 μm), as characterised by a laser direct infrared (LDIR) chemical imaging system, amounts to 669 particles per mm2 per year for PP and 187 particles per mm2 per year for HDPE, exhibiting average particle sizes of 60 μm and 23 μm in the same order. Furthermore, surface microscopy provided valuable insights into the dominant erosion mechanisms, revealing three distinct zones and the surface features reveal the brittle erosion behaviours. These results will enable a better assessment of degradation and lifetime prediction of plastics in turbid rivers and coastal oceans, allowing precise estimation of the rate of formation of MPs.

The impact of floods on plastic pollution

Abstract Non-Technical Summary Plastic harms ecosystem health and human livelihood on land, in rivers, and in the sea. To prevent and reduce plastic pollution, we must know how plastics move through the environment. Extreme events, such as floods, bring large amounts of plastic into rivers around the world. This article summarizes how different flood types (excessive rainfall, high river flow, or floods from the sea) flush or deposit plastic pollution, and how this impacts the environment. Furthermore, this paper also discusses how improved resilience to floods is important to prevent and reduce plastic pollution. Technical Summary Plastic pollution is ubiquitous in the environment and threatens terrestrial, freshwater, and marine ecosystems. Reducing plastic pollution requires a thorough understanding of its sources, sinks, abundance, and impact. The transport and retention dynamics of plastics are however complex, and assumed to be driven by natural factors, anthropogenic factors, and plastic item characteristics. Current literature shows diverging correlations between river discharge, wind speed, rainfall, and plastic transport. However, floods have been consistently demonstrated to impact plastic transport and dispersal. This paper presents a synthesis of the impact of floods on plastic pollution in the environment. For each specific flood type (fluvial, pluvial, coastal, and flash floods), we identified the driving transport mechanisms from the available literature. This paper introduces the plastic-flood nexus concept, which is the negative feedback loop between floods (mobilizing plastics), and plastic pollution (increasing flood risk through blockages). Moreover, the impact of flood-driven plastic transport was assessed, and it was argued that increasing flood resilience also reduces the impact of floods on plastic pollution. This paper provides a perspective on the importance of floods on global plastic pollution. Increasing flood resilience and breaking the plastic-flood nexus are crucial steps toward reducing environmental plastic pollution. Social Media Summary Floods have a large impact on plastic pollution transport, which can be reduced through improved flood resilience

Specialized metabolite modifications in Brassicaceae seeds and plants: diversity, functions and related enzymes.

Covering: up to 2023Specialized metabolite (SM) modifications and/or decorations, corresponding to the addition or removal of functional groups (e.g. hydroxyl, methyl, glycosyl or acyl group) to SM structures, contribute to the huge diversity of structures, activities and functions of seed and plant SMs. This review summarizes available knowledge (up to 2023) on SM modifications in Brassicaceae and their contribution to SM plasticity. We give a comprehensive overview on enzymes involved in the addition or removal of these functional groups. Brassicaceae, including model (Arabidopsis thaliana) and crop (Brassica napus, Camelina sativa) plant species, present a large diversity of plant and seed SMs, which makes them valuable models to study SM modifications. In this review, particular attention is given to the environmental plasticity of SM and relative modification and/or decoration enzymes. Furthermore, a spotlight is given to SMs and related modification enzymes in seeds of Brassicaceae species. Seeds constitute a large reservoir of beneficial SMs and are one of the most important dietary sources, providing more than half of the world's intake of dietary proteins, oil and starch. The seed tissue- and stage-specific expressions of A. thaliana genes involved in SM modification are presented and discussed in the context of available literature. Given the major role in plant phytochemistry, biology and ecology, SM modifications constitute a subject of study contributing to the research and development in agroecology, pharmaceutical, cosmetics and food industrial sectors.

Small micro- and nanoplastic test and reference materials for research: Current status and future needs

Abstract Environmental plastic pollution comprises partially degraded particles representing a continuum of sizes, shapes, polymer types and chemical compositions. Owing to their potential for biological uptake, small microplastic particles (sMP; <100 μm) and nanoplastics (NPs) are considered to be a potential risk to organisms. Understanding how sMPs and NPs behave in the environment, and how environmental matrices affect their detection, is fundamental to quantifying exposures, assessing hazards and understanding these risks. For this purpose, high-quality, well-characterised and environmentally relevant test and reference materials are crucial. The current lack of environmentally relevant sMP and NP reference materials has resulted in many studies applying commercially available spherical, homogenous and monodisperse particles, typically produced for specific purposes and without environmental relevance. There is a need for sMP and NP test/reference materials for fate and effects assessments and analytical protocol validation that more accurately represent the sMP and NP present in the environment. To date, feasible methods for producing relevant sMP and NP test materials in sufficient quantities for environmental fate and effects studies remain lacking. The current review provides an overview and comparison of the available methods, highlighting those that show the most promise for producing environmentally relevant sMP and NP with further development and optimisation.

The influence of the interaction of the genotype and the environment on productivity Actinidia deliciosa (kiwi) in wet subtropics of Russia

The placement of the Actinidia deliciosa culture in the wet subtropics of Russia is based on an assessment of the influence of agroclimatic conditions on the crop of culture in the plant-environment system. Factors have been established that limit the territory of possible cultivation of actinidia delicious in terms of frost resistance, as well as the properties of soils that limit its productivity. The results of the study of the soil cover and the properties of the main types of soils of the moist-subtropical zone of the Russian Federation and the assessment of agricultural land by the criterion of equilibrium density and power of the soil profile formed the basis of their suitability for the culture of A. Deliciosa. The agroecological characteristic of its varieties is represented by indicators of environmental plasticity and potential productivity.

Selection of watermelon starting material by adaptability for breeding for suitability for intensive and organic growing technologies

Purpose and Objectives. To select watermelon starting materials by major productive indicators (yield, average marketable fruit weight) for the breeding of genotypes suitable for intensive and organic cultivation technologies.
 Materials and Methods. Collection watermelon accessions were studied: 101 cultivars and lines from 9 countries. Cv. ‘Maks Plus’ (Ukraine) was taken as the control accession. The following parameters were determined: Sgi – genotype’s stability, bi – regression coefficient of the genotype's response to changing conditions (plasticity), GBVi – genotype’s breeding value. Plants were grown by traditional technology in the Forest-Steppe of Ukraine (DSTU 3805-98, 1998; DSTU 5045:2008, 2008). Watermelon plants were fertilized and protected in compliance with scientific and practical recommendations. The study was conducted in accordance with routine methods of breeding. Kilchevskiy & Khotylyova’s method, 1997 was used to estimate the genotypes’ stability parameters. The coefficient of environmental plasticity (bi) was calculated by Eberhart & Russel algorithm, 1966. Data were statistically and mathematically processed in Statistica 6.
 Results and Discussion. The adaptive potential of the watermelon collection was evaluated for the following characteristics: total and marketable yields and average marketable fruit weight. The following parameters were determined: bi - coefficient of regression of the genotype’s response to changes in conditions (plasticity), Sgi – genotype’s stability, and GBVi – genotype’s breeding value of the watermelon collection. We established the amplitudes and ranges of variation of the yield indicators. By the coefficient of environmental plasticity bi, the collection watermelon accessions were grouped as showing low, medium or high environmental plasticity for different traits. The collection accessions were categorized as follows: 1 - intensive genotypes with enhanced responses to growing conditions; 2 - with medium environmental plasticity; 3 - highly plastic, which slightly respond to changes in growing conditions. For breeding for various traits, we identified accessions of practical value in terms of stability parameters and genotype’s breeding value (GBVi) for intensive and organic cultivation technologies. Taking into account the environmental variability parameters in collection watermelon accessions to be used in the breeding of cultivars and hybrids suitable for intensive technologies, we selected accessions with enhanced responses to changing growing conditions, which also consistently yielded sufficiently high. As to the yield constituents (productive traits), 5 breeding-valuable accessions were selected by the "total yield" trait, 6 – by the "marketable yield" trait, and 1 – by the "average fruit weight" trait. Analysis of the environmental variability parameters in the watermelon collection to be used as starting materials in the breeding of genotypes suitable for organic cultivation enabled us to select a number of accessions by productive traits: 6 breeding-valuable accessions were distinguished due to the "total yield" trait, 4 – due to the "marketable yield" trait, and 6 - due to the "average fruit weight" trait. The selected accessions optimally responded to year’s conditions and were relatively stable in terms of high levels of expression of these traits under in changing growing conditions.
 Conclusions. For the breeding of genotypes suitable for intensive technologies, accessions with enhanced responses to changing growing conditions were selected; at the same time, they maintained a sufficiently high stability of yields. The breeding-valuable accessions were selected by yield constituents: 5 - by the "total yield" trait; 6 – by the "marketable yield" trait; and 1 – by the "average fruit weight" trait.
 Analysis of the environmental variability parameters in the watermelon collection to be used as starting materials in the breeding of genotypes suitable for organic cultivation enabled us to select a number of accessions: 6 – by the "total yield" trait; 4 – by the "marketable yield" trait; and 6 - by the characteristic "average fruit weight" trait. The selected accessions optimally responded to changing conditions of cultivation and showed relatively stable and strong expression of these traits.

Ecological plasticity and sustainability of cotton in the Southern Steppe of Ukraine

Depending on the length of the cotton growing season, the area of cultivation and its highest productivity potential are determined, and the prompt ripening of raw cotton allows for home-grown harvesting and high-quality soil preparation. The purpose of this study was to identify samples adapted to the conditions of the Southern Steppe of Ukraine from the cotton gene pool. The study used methods of plant variety expertise: phenological observations, morphological studies, and evaluation of breeding material for valuable traits. Based on the study results, parental components were selected to expand the process of forming early-ripening forms and productivity of raw cotton. The ability of cotton plants to grow in extreme conditions of the Southern Steppe of Ukraine was assessed and its homogeneity or stability, the index of growing conditions, the coefficient of variation – the difference in the numerical values of the trait duration of the period “germination – beginning of flowering” of plants in varieties with different growing season and their fluctuations around the average value were determined. It was found that according to the determined plasticity (bi), the variance of stability (Si2), and the coefficient of variation of the duration of “germination – the beginning of flowering” higher tolerance to environmental factors was characterised by ultra-early ripening varieties. The average regression coefficient (bi ) was -0.36; the variation in the duration of the period by year was 10.1%, which is significantly lower compared to early-ripening varieties – -0.77% and 12.9%, mid-ripening varieties – -0.80% and 15.0%, and late-ripening varieties – -1.30% and 16.6%, respectively. The maximum average productivity to frosty raw cotton of 49.4 g/plant was formed by the sample Pidozerskyi 4 (UF0800003), the duration of the period “germination – beginning of flowering” was 47 days, and “germination – full ripening” – <103 days. The lowest raw cotton productivity of 21.2 g/plant was demonstrated by the late-ripening sample Joloten 32 (IU14056549) of Turkmen selection, the duration of the growing season of which was 145 days on average over the years of research. The findings of this study will be used in further breeding to create high-yielding cotton varieties with increased environmental plasticity and stability and highquality fibre

From pollution to solutions: Insights into the sources, transport and management of plastic debris in pristine and urban rivers

River systems are important recipients of environmental plastic pollution and have become key pathways for the transfer of mismanaged waste from the land to the ocean. Understanding the sources and fate of plastic debris, including plastic litter (>5 mm) and microplastics (MPs) (<5 mm), entering different riverine systems is essential to mitigate the ongoing environmental plastic pollution crisis. We comprehensively investigated the plastic pollution in the catchments of two rivers in the Yangtze River basin: an urban river, the Suzhou section of the Beijing-Hangzhou Grand Canal (SZ); and a pristine rural river, the Jingmen section of the Hanjiang River (JM). The abundance of plastic pollutants in SZ was significantly higher than in JM: 0.430 ± 0.450 items/m3 and 0.003 ± 0.003 items/m3 of plastic litter in the water; 23.47 ± 25.53 n/m3 and 2.78 ± 1.55 n/m3 MPs in the water; and 218.82 ± 77.40 items/kg and 5.30 ± 1.99 items/kg of MPs in the sediment, respectively. Plastic litter and MPs were closely correlated in abundance and polymer composition. Overall, the polymer type, shape and color of MPs were dominant by polypropylene (42.5%), fragment (60.4%) and transparent (40.0%), respectively. Source tracing analysis revealed that packaging, shipping, and wastewater were the primary sources of plastic pollutants. The mantel analysis indicated that socio-economic and geospatial factors play crucial roles in driving the hotspot formation of plastic pollution in river networks. The composition of the MP communities differed significantly between the sediments and the overlying water. The urban riverbed sediments had a more pronounced pollutant ‘sink’ effect compared with the pristine rivers. These findings suggested that the modification of natural streams during urbanization may influence the transport and fate of plastic pollutants in them. Our results offer pivotal insights into effective preventive measures.

Utilization of disposable face masks for cultivation of Pleurotus ostreatus mushroom as a strategy for reducing environmental plastic pollution

Utilization of disposable face masks for cultivation of Pleurotus ostreatus mushroom as a strategy for reducing environmental plastic pollution

Developmental and environmental plasticity in opsin gene expression in Lake Victoria cichlid fish.

In many organisms, sensory abilities develop and evolve according to the changing demands of navigating, foraging, and communication across different environments and life stages. Teleost fish inhabit heterogeneous light environments and exhibit a large diversity in visual system properties among species. Cichlids are a classic example of this diversity; visual system variation is generated by different tuning mechanisms that involve both genetic factors and phenotypic plasticity. Here, we document the developmental progression of visual pigment gene expression in Lake Victoria cichlids and test if these patterns are influenced by variation in light conditions. We reared two sister species of Pundamilia to adulthood in two distinct visual conditions that resemble the light environments that they naturally inhabit in Lake Victoria. We also included interspecific first-generation hybrids. We focused on the four opsins that are expressed in Pundamilia adults (using real-time quantitative polymerase chain reaction (RT-qPCR)) (SWS2B, SWS2A, RH2A, and LWS) at 17 time points. We find that opsin expression profiles progress from shorter-wavelength sensitive opsins to longer-wavelength sensitive opsins with increasing age, in both species and their hybrids. The developmental trajectories of opsin expression also responded plastically to the visual conditions. Developmental and environmental plasticity in opsin expression may provide an important stepping stone in the evolution of cichlid visual system diversity.

Biodegradation of plastics in the pelagic environment of the coastal zone – Proposed test method under controlled laboratory conditions

The increasing quantities of plastic litter accumulated in the oceans, including microplastics, represent a serious environmental threat. Despite the recent legislative actions, the plastic littering problem will not disappear in a short time. It may, however be ameliorated by replacing conventional non-degradable plastics with bio-based materials biodegradable in marine environment (targeting the non-recycled or mismanaged plastic waste). Although priority is set to prevention of plastic litter by means of the circular economy principles, biodegradability is a means of controlling unintentional plastic pollution. In this effort, the development of reliable test methods that would be used along with standard specifications for determining the biodegradability of novel polymeric materials or plastics in marine environments, is a necessary complementary component of the whole strategy to control the marine plastic litter and micro-, nano-plastics threat. The present work focuses on identifying gaps and improving available laboratory test methods for measuring the aerobic biodegradation of plastics in the seawater column within the coastal zone (pelagic environment). The research work followed a methodology that is based on recommendations of ASTM D6691:2017 concerning biodegradation of plastics in the seawater and the similar ISO 23977-1:2020. Three different implementation schemes of the test method were applied using different experimental setups and measuring techniques for monitoring the evolved CO2. The effect of critical parameters affecting nutrient adequacy (concentration in inoculum) and oxygen adequacy (bioreactor size, sample size, frequency of aeration) on the biodegradation of four tested materials was explored, and optimal values are proposed. The results allowed for the refinement of the proposed test method to improve reliability and reproducibility.

Nanoplastic Stimulates the Amyloidogenesis of Parkinson's Alpha-Synuclein NACore.

Environmental plastic wastes are potential health hazards due to their prevalence as well as their versatility in initiating physical, chemical, and biological interactions and transformations. Indeed, recent research has implicated the adverse effects of micro- and nano-plastics, including their neurotoxicity, yet how plastic particulates may impact the aggregation pathway and toxicity of amyloid proteins pertinent to the pathologies of neurological diseases remains unknown. Here, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) is employed to reveal the polymorphic oligomerization of NACore, a surrogate of alpha-synuclein that is associated with the pathogenesis of Parkinson's disease. These data indicate that the production rate and population of the NACore oligomers are modulated by their exposure to a polystyrene nanoplastic, and these cellular assays further reveal an elevated NACore toxicity in microglial cells elicited by the nanoplastic. These simulations confirm that the nanoplastic-NACore association is promoted by their hydrophobic interactions. These findings are corroborated by an impairment in zebrafish hatching, survival, and development in vivo upon their embryonic exposure to the nanoplastic. Together, this study has uncovered the dynamics and mechanism of amyloidogenesis elevated by a nanoplastic trigger, shedding a new light on the neurological burden of plastic pollution.

LHP1-mediated epigenetic buffering of subgenome diversity and defense responses confers genome plasticity and adaptability in allopolyploid wheat

Polyploidization is a major driver of genome diversification and environmental adaptation. However, the merger of different genomes may result in genomic conflicts, raising a major question regarding how genetic diversity is interpreted and regulated to enable environmental plasticity. By analyzing the genome-wide binding of 191 trans-factors in allopolyploid wheat, we identified like heterochromatin protein 1 (LHP1) as a master regulator of subgenome-diversified genes. Transcriptomic and epigenomic analyses of LHP1 mutants reveal its role in buffering the expression of subgenome-diversified defense genes by controlling H3K27me3 homeostasis. Stripe rust infection releases latent subgenomic variations by eliminating H3K27me3-related repression. The simultaneous inactivation of LHP1 homoeologs by CRISPR–Cas9 confers robust stripe rust resistance in wheat seedlings. The conditional repression of subgenome-diversified defenses ensures developmental plasticity to external changes, while also promoting neutral-to-non-neutral selection transitions and adaptive evolution. These findings establish an LHP1-mediated buffering system at the intersection of genotypes, environments, and phenotypes in polyploid wheat. Manipulating the epigenetic buffering capacity offers a tool to harness cryptic subgenomic variations for crop improvement.

Phytochemical and biological investigations on Centranthus kellereri (Stoj., Stef. & T. Georgiev) Stoj. & Stef. and C. ruber (L.) DC. and their potential as new medicinal and ornamental plants.

Centranthus kellereri is a Bulgarian endemic plant species, found only in two locations in the world: The Balkans Mountains (Stara Planina), above the town of Vratsa, and The Pirin Mountains, above the town of Bansko, Bulgaria. Being endemic and endangered species precluded any significant research on it. The hypothesis of this study was that the populations of C. kellereri may represent genetically, phytochemically, and morphologically distinct forms and these will differentiate from C. ruber. Furthermore, C. kellereri possibly imperfect embryology may preclude its more widespread distribution under natural conditions. This study revealed the phytochemical profile, antioxidant activity, embryology, surface microstructural morphological traits, and genetic differences between the C. kellereri plants from the only two natural populations and compares them to the ones of the related and better-known plant C. ruber. The essential oil (EO) content in aboveground plant parts and in roots was generally low and the EO composition varied significantly as a function of plant part, year of sampling, location, and species. Methylvaleric acid was a major EO constituent in the C. kellereri EO, ranging between 60.2% and 71.7% of the total EO. The EO included monoterpenes, sequiterpenes, long-chain alkanes and fatty acids. Phytochemical analyses of plant tissue revealed the occurrence of 32 compounds that were tentatively identified as 6 simple phenolics, 18 flavonoids, 1 quinone, 1 lipid, 1 alkaloid, 2 diterpenes, and 3 triterpenes. There were differences in detected compounds between the C. kellereri plants at the two locations and between the roots and shoots in both species. The total phenols and flavonoids varied between the two species but were also dissimilar between the plants from the two populations of C. kelleri. Free radical scavenging activity, measured with ABTS and DPPH in aqueous and methanol extracts, had similar values; however, overall, C. kellereri from Vratsa showed the highest antioxidant activity while C. ruber had the lowest activity. Genetic analyses showed a clear differentiation between C. kellereri and C. ruber, and between the two populations of C. kellereri. Embryological studies revealed the peculiarities of the male and female generative spheres of the two species that were defined as being sexually reproducing. The pollen had high viability; however, the low viability of seeds demonstrated possible high sensitivity of C. kellereri to the environmental conditions, perhaps the main factor modifying and restricting the population sizes. The SEM analyses exposed differences in surface microstructural traits between the species (C. kellereri and C. ruber) but also between the two populations of C. kellereri. The observed dissimilarities in genetic makeup, micromorphological characteristics, and phytochemical composition strongly indicate that the two populations can be classified as distinct subspecies or varieties of C. kellereri; var. pirinensis and var. balkanensis. Further research is needed to introduce C. kellereri into culture and develop it as a high-value specialty crop or ornamental in order to conserve C. kellereri natural populations. C. kellereri may be utilized as a source for phytochemicals of interest and as an ornamental plant like C. ruber; however, it may have a greater environmental plasticity and adaptation as evidenced by its current locations.

Quantification of the vertical transport of microplastics by biodeposition of typical mariculture filter-feeding organisms

The tremendous loss of microplastics from the sea surface and the low density of microplastics found in the water column and sediments indicate that the oceans have mechanisms capable of transporting microplastics from the surface to the seafloor. These include physicochemical processes and biological influences from marine organisms that drive the vertical migration of microplastics. Little is known, however, about the biological processes involved in the deposition of plastics in the marine environment. A considerable number of mariculture filter-feeding organisms can consume substantial amounts of suspended substances in the water column, and these organisms are ideal candidates for depositing microplastics. In this study, we analyzed microplastic abundance in typical mariculture filter feeders, i.e., ascidians (Halocynthia roretzi), oysters (Crassostrea gigas), scallops (Chlamys farreri) and clams (Ruditapes philippinarum), quantified the number and characteristics of the microplastics they deposited in situ, and further compared microplastic biodeposition rates. Microplastics were present in feces and pseudofeces and sank to form biodeposits rather than accumulating to significant levels in organisms. Microplastics were found in significantly higher numbers in the biodeposits of mariculture organisms than in the control deposits (p < 0.01). The shape and color of the microplastics in the sediments were not impacted by the presence of organisms (p > 0.05), but the deposition of <1000 μm and positive-buoyancy (less dense than seawater) microplastics was significantly increased in the biodeposits (p < 0.05). The highest microplastic biodeposition rate was found in scallops (1.14 ± 0.07 items·ind−1·d−1 or 0.5 ± 0.03 items·g−1·d−1). These results suggest that mariculture filter-feeding organisms have important biodepositional functions that influence the fate of microplastics through the transfer of microplastics from the surface to the seafloor. This study could contribute to a better understanding of the biological plastic pump mechanisms in oceans.