Interactions between microplastics and organic contaminants: The microbial mechanisms for priming effects of organic compounds on microplastic biodegradation.

The co-presence of plastics and other organic contaminants is pervasive in various ecosystems, particularly in areas with intensive anthropogenic activities. Their interactions inevitably impact the composition and functions of the plastisphere microbiome, which in turn determines the trajectory of these contaminants. Antibiotics are a group of organic contaminants that warrant particular attention due to their wide presence in environments and significant potential to disseminate antibiotic resistance genes (ARGs) within the plastisphere. Therefore, this study investigated the impacts of sulfadiazine (SDZ), a prevalent environmental antibiotic, on the composition and function of the plastisphere microbial community inhabiting micro-polyethylene (mPE), one of the most common microplastic contaminants. Our findings indicated that the presence of SDZ increased the overall plastisphere microbial abundance and enriched populations that are capable of degrading both SDZ and mPE. The abundance of Aquabacterium, a dominant plastisphere population that is capable of degrading both SDZ and mPE, increased over the course of SDZ exposure, while another abundant mPE-degrading population, Ketobacter, remained stable. Accordingly, the removal of SDZ was enhanced in the presence of mPE. Moreover, the results further revealed that not only SDZ but also other labile organic contaminants (e.g., aniline and hexane) could accelerate mPE biodegradation through a priming effect. This investigation underscores the complex dynamics among microplastics, organic contaminants, and the plastisphere microbiome, offering insights into the environmental fate of plastic and antibiotic pollutants.

EDDS application destabilizes soil organic matter in phytoremediation: Insights from quantity and molecular composition of dissolved organic matter.

The stability of soil organic matter (SOM) is crucial for metal transport and carbon cycling. S,S-ethylenediaminedisuccinic acid (EDDS) is widely used to enhance phytoremediation efficiency for heavy metals in contaminated soils, yet its specific impacts on SOM have been underexplored. This study investigates the effects of EDDS on SOM stability using a rhizobox experiment with ryegrass. Changes in soil dissolved organic matter (DOM) quantity and molecular composition were analyzed via Fourier transform ion cyclotron resonance mass spectrometry. Results showed that the use of EDDS increased the uptake of Cu, Cd and Pb by ryegrass, but simultaneously induced the destabilization and transformation of SOM. After 7 days of EDDS application, dissolved organic carbon (DOC) and nitrogen (DON) concentrations in rhizosphere soils increased significantly by 3.44 and 10.2 times, respectively. In addition, EDDS reduced lipids (56.3%) and proteins/amino sugars-like compounds (52.1%), while increasing tannins (9.11%) and condensed aromatics-like compounds (24.4%) in the rhizosphere DOM. These effects likely stem from EDDS's dual action: extracting Fe/Al from SOM-mineral aggregates, releasing SOM into the DOM pool, and promoting microbial degradation of bioavailable carbon through chain scission and dehydration. Our study firstly revealed that the application of EDDS in phytoremediation increased the mineralization of SOM and release of CO2 from soil to the atmosphere, which is important to assess the carbon budget of phytoremediation and develop climate-smart strategy in future.

Physio-biochemical mechanism of melatonin seed priming in stimulating growth and drought tolerance in bread wheat.

Drought stress (DS) adversely affects a plant's development and growth by negatively altering the plant's physio-biochemical functions. Previous investigations have illustrated that seed priming with growth regulators is an accessible, affordable, and effective practice to elevate a plant's tolerance to drought stress. Melatonin (MT) is derived from the precursor tryptophan and can improve germination, biomass, and photosynthesis under stress conditions. The current study examined the effect of melatonin seed priming on two wheat cultivars (Fakhar-e-Bhakkar and Akber-19) cultivated under severe drought conditions (35% FC). There were 6 levels of melatonin (i.e., M0 = control, M1 = 1 mg L- 1, M2 = 2 mg L- 1, M3 = 3 mg L- 1, M4 = 4 mg L- 1 and M5 = mg L- 1) which were used for seed priming. Our results confirmed that seed priming with M2 = 2 mgL- 1 concentration of MT alleviates the negative effects of DS by boosting the germination rate by 54.84% in Akber-19 and 33.33% in Fakhar-e-Bhakkar. Similarly, leaf-relative water contents were enhanced by 22.38% and 13.28% in Akber-19 and Fakhar-e-Bhakkar, respectively. Melatonin pre-treatment with 2 mgL- 1 significantly enhanced fresh and dry biomass of shoot and root, leaf area, photosynthetic pigments, osmoprotectants accumulation [total soluble proteins (TSP), total free amino acids (TFAA), proline, soluble sugars, glycine betaine (GB)] and lowered the amount of malondialdehyde (MDA) and hydrogen peroxide (H2O2) production by elevating antioxidants [Ascorbic acid, catalase (CAT), Phenolics, peroxidase (POD) and superoxide dismutase (SOD)] activity under drought stress (DS). Meanwhile, under control conditions (NoDS), the melatonin treatment M1 = 1 mgL- 1 effectively enhanced all the growth-related physio-biochemical attributes in both wheat cultivars. In the future, more investigations are suggested on different crops under variable agroclimatic conditions to declare 2 mgL- 1 melatonin as an efficacious amendment to alleviate drought stress.

Bacterial seed endophytes promote barley growth and inhibits Fusarium graminearum in vitro.

OBJECTIVES: Seeds host microbes that function in plant growth and phytopathogen resistance. The aim of the work was to investigate total bacterial community in malting barley seeds and whether their bacterial seed endophytes have dual functional roles in plant growth-promotion and inhibition of Fusarium graminearum, the causative agent of Fusarium head blight (FHB) in barley. We used culture dependent and culture independent methods. RESULTS: Phylogenetic classification of seed endophytic bacteria based on sequencing data identified B. subtilis, B. licheniformis and B. pumilis as predominant subgroups. Location driven divergence in bacterial endophytic communities was evident based on a clear separation of the samples from Crookston and other location samples. The bio-primed seeds using one hundred and seventy bacterial isolates showed that 3.5% (6/170) of the bacterial isolates conferred greater than 10% increase in both root length (RL) and shoot length (SL), while 19.4% (33/170) and 26.5% (45/170) showed RL and SL specific growth effects, respectively, relative to controls. Among the six bacterial isolates that increased RL and SL, five (#29, #63, #109, #124 and #126) also significantly inhibit the growth of F. graminearum based on in vitro assays. This study identified novel seed bacterial endophytes that could be further exploited for promoting growth during seedling establishment and as biocontrol for combating the devastating scab disease.

Protocol for a randomized controlled trial: exercise-priming of CBT for depression (the CBT+ trial).

BACKGROUND: Depression is a leading cause of disability worldwide, and treatments could be more effective. Identifying methods to improve treatment success has the potential to reduce disease burden dramatically. Preparing or "priming" someone to respond more effectively to psychotherapy (e.g., cognitive behavioral therapy [CBT]) by preceding sessions with aerobic exercise, a powerful neurobiological activator, could enhance the success of the subsequently performed therapy. However, the success of this priming approach for increasing engagement of working mechanisms of psychotherapy (e.g., increased working alliance and behavioral activation) has yet to be formally tested. METHODS: The CBT + trial will be a parallel-arm randomized controlled trial that will recruit 40 adult participants with DSM-5 diagnosed depression (verified with clinical interview) via referrals, mass emails, local flyers, and social media posts. Participants will be randomized to an ActiveCBT or CalmCBT condition. The ActiveCBT group will receive an 8-week CBT intervention primed with 30 min of moderate-intensity aerobic exercise (cycling on a stationary bike at a 13 rating of perceived exertion). The CalmCBT group will receive the same 8-week CBT intervention while resting for 30 min before CBT (i.e., cycling vs no cycling is the only difference). The primary outcome measures will be mean working alliance (assessed with the client version of the Working Alliance Inventory-Short Revised) and mean behavioral activation (self-reported Behavioral Activation for Depression Scale) recorded at each of the 8 therapy sessions. Secondary outcomes include evaluation of state anhedonia and serum brain-derived neurotrophic factor before the active/calm conditions, between the condition and therapy, and after the therapy. Additional exploratory analyses will evaluate group differences in algorithm-generated ratings of therapist-participant interactions via the Lyssn platform. DISCUSSION: The novel approach of priming CBT with moderate-intensity aerobic exercise evaluated in a randomized controlled trial (CBT + trial) has the potential to demonstrate the usefulness of exercise as an augmentation strategy that improves working mechanisms of therapy and overall treatment outcomes for adults with depression. TRIAL REGISTRATION: ClinicalTrials.gov NCT06001346 . Registered on August 21, 2023.

Top-down attention shifts behavioral and neural event boundaries in narratives with overlapping event scripts.

Understanding and remembering the complex experiences of everyday life relies critically on prior schematic knowledge about how events in our world unfold over time. How does the brain construct event representations from a library of schematic scripts, and how does activating a specific script impact the way that events are segmented in time? We developed a novel set of 16 audio narratives, each of which combines one of four location-relevant event scripts (restaurant, airport, grocery store, and lecture hall) with one of four socially relevant event scripts (breakup, proposal, business deal, and meet cute), and presented them to participants in an fMRI study and a separate online study. Responses in the angular gyrus, parahippocampal gyrus, and subregions of the medial prefrontal cortex (mPFC) were driven by scripts related to both location and social information, showing that these regions can track schematic sequences from multiple domains. For some stories, participants were primed to attend to one of the two scripts by training them to listen for and remember specific script-relevant episodic details. Activating a location-related event script shifted the timing of subjective event boundaries to align with script-relevant changes in the narratives, and this behavioral shift was mirrored in the timing of neural responses, with mPFC event boundaries (identified using a hidden Markov model) aligning to location-relevant rather than socially relevant boundaries when participants were location primed. Our findings demonstrate that neural event dynamics are actively modulated by top-down goals and provide new insight into how narrative event representations are constructed through the activation of temporally structured prior knowledge.

Magnesium as an Adjuvant to Rocuronium to Improve Intubation Conditions and Shorten the Intubation Time: A Randomized Controlled Study.

AIM AND OBJECTIVE: The purpose of the study is to compare the effects of rocuronium priming with the combined technique of magnesium pretreatment and rocuronium priming and to investigate whether this pretreatment could further accelerate the onset of neuromuscular blockade during intubation. MATERIALS AND METHODS:  A double-blinded randomized controlled trial (RCT) clinical study was done on patients at a tertiary care center for six months after obtaining approval from the institutional ethical committee. A total of 150 patients were randomly allocated as Group MP (infusion of 50 mg/kg of MgSo4 over 10 min was given 10 mins prior to premedication and dose of rocuronium 0.06 mg/kg given three minutes), Group P (priming dose of rocuronium 0.06 mg/kg given three minutes before the intubating dose), and Group C (control group with the same volume of 0.9% saline and rocuronium bolus of 0.6 mg/kg on intubation). Parameters such as demographic and hemodynamical data, American Society of Anesthesiologists (ASA) score, Mallampati scoring, neuromuscular monitoring, intubation grading, and number of successful/failed attempts were recorded. RESULTS:  Our results showed that Group MP had a rapid onset of action of rocuronium with 58.90 +/- 4.77 seconds and a longer duration of action of rocuronium with 54.92 +/- 10.39 minutes, which are statistically significant compared to Group P (onset of action of ROC 106.70 +/- 4.24 seconds and duration of action rocuronium 45.88 +/- 6.22 minutes) and Group C (onset of action of ROC 154.56 +/- 11.39 seconds and duration of ROC 40.56 +/- 3.96 minutes). The maximum number of patients in Group MP (33 patients) showed good intubation conditions compared to Group P (23 patients) and Group C (16 patients), which was statistically significant. CONCLUSION: We conclude that magnesium sulfate pretreatment in combination with rocuronium priming (Group MP) considerably accelerates the onset of rocuronium action, increases the duration of action of rocuronium, and enhances the intubation procedure without any adverse effect of rocuronium and magnesium sulfate.

Warm-Up in Triathlon: Do Triathletes Follow the Scientific Guidelines?

PURPOSE: Warming up before competition is universally recognized as an effective way to enhance performance. However, only a few articles have directly investigated different warm-up strategies adopted by triathletes and suggested by coaches. The Olympic-distance triathlon is an endurance competition characterized, at least for the elite, by a fast start with a strong correlation to the final position in the race. Thus, executing a proper warm-up protocol would be beneficial in optimizing performance. The present study aimed to provide an overview of the warm-up protocol adopted/suggested by national-caliber triathletes/coaches before an Olympic-distance triathlon race. METHODS: Online surveys were created and shared between national- and international-caliber Italian, French, and Spanish triathletes and coaches. Information about the rationale, structure, and specific exercises adopted/suggested during personal warm-up protocols was collected. Thereafter, triathletes were grouped according to the discipline sequence reported. RESULTS: Seventy-nine triathletes and nineteen coaches completed the survey. The cycle-run-swim was the most reported discipline sequence adopted, with a total time of 90.0 (25.0) minutes, against the 62.5 (25.0) minutes suggested by coaches. Conditioning exercises were performed by only 31.6% of triathletes 20 to 10 minutes before the race start. CONCLUSIONS: Triathletes who took part in this survey adopted very long protocols with the specific intention of including all disciplines. These results highlight the need to raise awareness in triathletes and coaches on the correct warm-up procedures and to stimulate researchers to design studies that directly investigate the effects of different warm-up protocols before competitions.

Dehydration priming remodels protein abundance and phosphorylation level regulating tolerance to subsequent dehydration or salt stress in creeping bentgrass.

Dehydration priming (DP) induces stress memory which plays a positive role in plant adaptability, but it is not well understood how DP differentially regulates subsequent dehydration (cis priming) or salt (trans priming) tolerance at the post-translational level. Purpose of this study was to identify proteins, phosphorylation levels and sites, and relevant metabolic pathways for DP-induced dehydration or salt tolerance in Agrostis stolonifera. DP-induced differentially regulated proteins (DEPs) were mostly located in the cytoplasm, chloroplast, and cell membrane, and differentially regulated phosphoproteins (DRPPs) were mostly nuclear proteins and cytoplasmic proteins. DP regulated common phosphorylation sites ([SP] and [RxxS]) under dehydration and salt conditions and also individually affected 8 or 11 phosphorylation sites under dehydration or salt stress. DP-regulated DRPPs were mainly rich in glycolysis and glutathione metabolism pathways, RNA splicing, and dynamin family proteins under dehydration stress, whereas DP-regulated salt tolerance was mainly related to chlorophyll metabolism, photosynthesis, MAPK signaling cascade, and ABC transporter I family at the phosphorylation level. In addition, the DP also significantly up-regulated phosphorylation of histones (ATXR3 and SETD1A) in response to subsequent dehydration and salt stress as well as abundances of antioxidant enzymes, dynamin family protein, and KCS6 under dehydration stress or abundances of PETE, HMGA, XTH, and ABCI6 under salt stress, respectively. Transcriptomics analysis also further indicated that DP-regulated dehydration or salt tolerance was also related to transcriptional regulation in the early stage. Current results provided better understanding of the role of stress memory in plant adaptability to repeated or crossed stress via post-translational modifications (PTMs). SIGNIFICANCE: Recurrent moderate drought may buffer drought legacies in many plant species. When plants were exposed to repeated drought stress, their adaptability to subsequent stress could be enhanced, which is known as "stress memory". Dehydration priming has been found to be an important approach to induce stress memory. Current results provided better understanding of the role of stress memory in plant adaptability to repeated or crossed stress via post-translational modifications.

Emojis and affective priming in visual word recognition.

Emojis are frequently used in digital communication to supplement the lack of non-verbal cues, but their integration during reading has not been thoroughly examined. This study explores the interplay between language and emotion by testing the influence of emotional valence and face-status of emojis on visual word recognition. Two online experiments were conducted with 92 native English-speaking university students, examining priming effects between congruent (e.g. [Formula: see text] delicious) and incongruent (e.g. [Formula: see text] hate) prime-target pairs, varying the face-status of the emoji prime (face vs. non-face) and the valence (positive vs. negative) of the word target. Irrespective of valence, face emojis demonstrated a processing advantage over non-face emojis, implying automatic attention capture. Additionally, the results revealed an interaction between prime-target congruency and valence, with a facilitatory effect for positive, but not negative, items, suggesting a valence-specific mechanism of affective priming in the lexical decision task. The research suggests that the rapid integration of emoji content occurs during the early stages of visual word recognition, with heightened attentional sensitivity to both face-like and positive stimuli when reading digital communications.

Enhancing physio-biochemical characteristics in okra genotypes through seed priming with biogenic zinc oxide nanoparticles synthesized from halophytic plant extracts.

Poor seedling germination and growth can result in large financial losses for farmers, thus, there is an urgent need for sustainable agricultural techniques to enhance seed germination and early growth. As an outcome, sustainable agriculture-which emphasizes the smart and effective utilization of resources-has gained popularity worldwide. At numerous levels, the field of nanotechnology is capable of significant benefit in achieving sustainable agricultural practices. Zinc oxide nanoparticles (ZnO NPs) have been shown to have biostimulatory properties and serve as effective solutions for addressing environmental and biotic stressors. The purpose of this study, investigating Salvadora persica halophytic leaf extract -synthesized zinc oxide nanoparticles (S-ZnONPs) as nano-priming agents to ensure okra seeds germinated under stress-free conditions. From an application perspective, we examined the effect of seed priming with varying concentrations of S-ZnO NPs (0, 20 and 40 ppm) for 18 and 24 h of soaking. Results indicated that the germination rate of hybrid variety improved with 20 ppm at 18 h, increasing by 58.22%, while mean germination time reduced by 24.62%. An enhancement trend was observed in the shoot, root length, shoot and root fresh weight, shoot and root dry weight of hybrid variety at 20ppm with 18 h priming by 34.2, 84.3, 80.2, 47.4, 50.3, and 36.2%, respectively. However, chlorophyll pigments chl a, chl b, and carotenoids was significantly raised in desi variety by 42.4, 79.31, and 142.29% with 20 ppm at 18 h priming. Hydrogen per oxide decreased up to 87.8% with 40 ppm at 24 h in hybrid variety, while, in desi variety H2O2 was reduced 88.3% with 20 ppm at 24 h. Non enzymatic antioxidant activities such as ascorbic acid, was highly increased 130.6% in hybrid at 24 h priming with 20 ppm dose. Flavonoids raised in same variety by 166.1% with 20 ppm at 18 h. Proline content was increased by 144.5% with 40ppm at 18 h. Moreover, Antioxidant enzymes, superoxide dismutase, peroxidase and catalase were significantly increased in both varieties with both levels of S-ZnO NPs and priming time. This cost-effective and environmentally safe technique to produce nanoparticles of different halophytic plants can maximize resource utilization, supporting sustainable agriculture by minimizing adverse environmental effects without compromising efficiency.

Impact of green carbon dot nanoparticles on seedling emergence, crop growth and seed yield in blackgram (Vigna mungo L. Hepper).

Carbon Dots (CDs) were synthesized from peanut shells (PNS) through pyrolysis and characterized using FTIR, XRD, HRTEM and BET analysis revealing an average size of 2-5 nm with amorphous nature. Synthesized PNS-CDs was employed both as priming and foliar agent for enhancing seed quality and crop productivity in blackgram (Vigna mungo L. Hepper). Different concentrations ranging from 50, 100, 200, 300, 400, 500 and 1000 ppm was used for seed priming and 5, 10, 15, 20, 25, 50, 75 and 100 ppm were given as foliar spray on 30th and 45th days after sowing (DAS). On accounting the best seed priming and foliar spray concentrations, field trial was conducted to validate the optimistic effect of PNS-CDs on blackgram crop productivity. Results revealed that priming with 200 ppm for 3 h exhibited maximum seed imbibition (54%), germination (88%) and vigour index (3165). Whereas, foliar spray with 50 ppm expressed significant improvement in leaf area index (2.6), total chlorophyll (2.70 mg/g), total soluble protein (71 mg/g), Number of nodules/plant (138), seed yield/plant (8.7 g) and 100 seed weight (5 g). The impact of PNS-CDs treatments resulted in increased photosynthetic rate (12.45 µmol CO2 m-2s-1), transpiration rate (3.13 mmol H2O/m-2s-1), stomatal conductance (0.55 mol H2O/m-2s-1) and internal leaf CO2 concentration (652 µmol CO2 m-2s-1) which ultimately enhanced the photosynthetic efficiency of plants. It has also exhibited a promising effect on the resultant seed in which the combination seed priming (200 ppm) followed by foliar spray (50 ppm) recorded maximum 100 seed weight (4.19 g), germination (97%) and vigour index (3019). Thus, this study highlights the promising role of PNS-CDs as a sustainable and effective agricultural nanomaterial, offering a novel approach to utilize the agricultural waste and also to enhance the crop productivity through advanced non-chemical approach.

Cytokine priming enhances the antifibrotic effects of human adipose derived mesenchymal stromal cells conditioned medium.

BACKGROUND: Fibrosis is a pathological scarring process characterized by persistent myofibroblast activation with excessive accumulation of extracellular matrix (ECM). Fibrotic disorders represent an increasing burden of disease-associated morbidity and mortality worldwide for which there are limited therapeutic options. Reversing fibrosis requires the elimination of myofibroblasts, remodeling of the ECM, and regeneration of functional tissue. Multipotent mesenchymal stromal cells (MSC) have antifibrotic properties mediated by secreted factors present in their conditioned medium (MSC-CM). However, there are no standardized in vitro assays to predict the antifibrotic effects of human MSC. As a result, we lack evidence on the effect of cytokine priming on MSC's antifibrotic effects. We hypothesize that the MSC-CM promotes fibrosis resolution in vitro and that this effect is enhanced following MSC cytokine priming. METHODS: We compared the antifibrotic effects of resting versus interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) primed MSC-CM in four in vitro assays: prevention of fibroblast activation, myofibroblasts deactivation, ECM degradation and fibrosis resolution in lung explant cultures. Furthermore, we performed transcriptomic analysis of myofibroblasts treated or not with resting or primed MSC-CM and proteomic characterization of resting and primed MSC-CM. RESULTS: We isolated MSC from adipose tissue of 8 donors, generated MSC-CM and tested each MSC-CM independently. We report that MSC-CM treatment prevented TGF-ß induced fibroblast activation to a similar extent as nintedanib but, in contrast to nintedanib, MSC-CM reduced fibrogenic myofibroblasts (i.e. transcriptomic upregulation of apoptosis, senescence, and inflammatory pathways). These effects were larger when primed rather than resting MSC-CM were used. Priming increased the ability of MSC-CM to remodel the ECM, reducing its content of collagen I and fibronectin, and reduced the fibrotic load in TGF-ß treated lung explant cultures. Priming increased the following antifibrotic proteins in MSC-CM: DKK1, MMP-1, MMP-3, follistatin and cathepsin S. Inhibition of DKK1 reduced the antifibrotic effects of MSC-CM. CONCLUSIONS: In vitro, MSC-CM promote fibrosis resolution, an effect enhanced following MSC cytokine priming. Specifically, MSC-CM reduces fibrogenic myofibroblasts through apoptosis, senescence, and by enhancing ECM degradation. Future studies will establish the in vivo relevance of MSC priming to fibrosis resolution.

Can sensory and semantic priming enhance the effects of guided self-compassion meditation? A proof-of-concept study.

Introduction: Self-compassion is a fundamental aspect of psychological health and well-being that can be cultivated through self-compassion meditations, but it remains unclear how to facilitate this most effectively. This study is the first to explore whether sensory and semantic priming introduced prior to a guided self-compassion meditation could enhance the effects of meditation in comparison with a control condition. Methods: The study was conducted with 3 × 3 repeated measures between-group design, including three groups (sensory priming, semantic priming and control group), and three assessment time points of state self-compassion, self-criticism, and positive and negative affect (at baseline, after priming, and after guided meditation). Additionally, a meditation appeal questionnaire was used. The total sample size included 71 students who underwent a 3-min priming intervention followed by a 15-min self-compassion guided meditation session. Results: First, prior to guided meditation, sensory priming significantly decreased state self-criticism more than the control condition or semantic priming, although some reliability issues of the applied self-criticism scale must be taken into consideration. Second, neither sensory nor semantic priming changed state self-compassion, positive affect or negative affect. Third, neither semantic nor sensory priming significantly enhanced the effects of guided self-compassion meditation either in positive and negative affect, self-compassion states, self-criticism states, or in the appeal of the meditation experience. Discussion: Although this study is underpowered (estimated post hoc power ranges from 0.20 to 0.42), the findings provide preliminary insights into the potential priming has as a tool to enhance meditation effects and provide guidelines for future studies.

Zinc oxide nanoparticles application alleviates salinity stress by modulating plant growth, biochemical attributes and nutrient homeostasis in Phaseolus vulgaris L.

Salt stress poses a significant challenge to global agriculture, adversely affecting crop yield and food production. The current study investigates the potential of Zinc Oxide (ZnO) nanoparticles (NPs) in mitigating salt stress in common beans. Salt-stressed bean plants were treated with varying concentrations of NPs (25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L) using three different application methods: foliar application, nano priming, and soil application. Results indicated a pronounced impact of salinity stress on bean plants, evidenced by a reduction in fresh weight (24%), relative water content (27%), plant height (33%), chlorophyll content (37%), increased proline (over 100%), sodium accumulation, and antioxidant enzyme activity. Application of ZnO NPs reduced salt stress by promoting physiological growth parameters. The NPs facilitated enhanced plant growth and reduced reactive oxygen species (ROS) generation by regulating plant nutrient homeostasis and chlorophyll fluorescence activity. All the tested application methods effectively mitigate salt stress, with nano-priming emerging as the most effective approach, yielding results comparable to control plants for the tested parameters. This study provides the first evidence that ZnO NPs can effectively mitigate salt stress in bean plants, highlighting their potential to address salinity-induced growth inhibition in crops.

The biological activity of bacterial rhamnolipids on Arabidopsis thaliana and the cyst nematode Heterodera schachtii is linked to their molecular structure.

Rhamnolipids (RLs) are amphiphilic compounds of bacterial origin that offer a broad range of potential applications as biosurfactants in industry and agriculture. They are reported to be active against different plant pests and pathogens and thus are considered promising candidates for nature-derived plant protection agents. However, as these glycolipids are structurally diverse, little is known about their exact mode of action and, in particular, the relation between molecular structure and biological activity against plant pests and pathogens. Engineering the synthesis pathway in recombinant Pseudomonas putida strains in combination with advanced HPLC techniques allowed us to separately analyze the activities of mixtures of pure mono-RLs (mRLs) and of pure di-RL (dRLs), as well as the activity of single congeners. In a model system with the plant Arabidopsis thaliana and the plant-parasitic nematode (PPN) Heterodera schachtii we demonstrate that RLs can significantly reduce infection, whereas their impact on the host plant varied depending on their molecular structure. While mRLs reduced plant growth even at a low concentration, dRLs showed a neutral to beneficial impact on plant development. Treating plants with dRLs triggered an increased reactive oxygen species (ROS) production, indicating the activation of stress-response signaling and possibly plant defense. Pretreatment of plants with mRLs or dRLs prior to application of flagellin (flg22), a known ROS inducer, further increased the ROS response to flg22. While dRLs stimulated an elevated flg22-induced ROS peak, a pretreatment with mRLs resulted in a prolonged synthesis of ROS indicating a generally elevated stress level. Neither mRLs nor dRLs induced the expression of plant defense marker genes of salicylic acid, jasmonic acid, and ethylene pathways. Detailed studies on dRLs revealed that even high concentrations up to 755 ppm of these molecules have no lethal impact on H. schachtii infective juveniles. Infection assays with individual dRL congeners showed that the C10-C8 acyl chained dRL was the only congener without effect, while dRLs with C10-C12 and C10-C12:1 acyl chains were most efficient in reducing nematode infection even at concentrations below 2 ppm. As determined by phenotyping and ROS measurements, A. thaliana reacted more sensitive to long-chained dRLs in a concentration-dependent manner. Our experiments show a clear structure-activity relation for the effect of RLs on plants. In conclusion, functional assessment and analysis of the mode of action of RLs in plants and other organisms require careful consideration of their molecular structure and composition.

Modulation of Plant Transcription Factors and Priming of Stress Tolerance by Plant Growth-Promoting Bacteria: A Systematic Review.

BACKGROUND: Plant growth-promoting bacteria (PGPB) have been shown to improve plant growth and stress tolerance through mechanisms including improved access to nutrients and biotic competition with pathogens. As such, the use of PGPB can help to address challenges to crop productivity, however, information on interactions between PGPB and their plant hosts, especially at the level of gene regulation, is distributed across diverse studies involving several different plants and PGPB. SCOPE: For this review, we analysed recent research publications reporting specifically on plant transcription factor (TF) expression in association with PGPB, to determine if there are any common findings and to identify gaps that offer opportunities for focused future research. CONCLUSIONS: The inoculation of plants with PGPB elicits a dynamic and temporal response. Initially, there is an upregulation of defence-responsive TFs, followed by their downregulation in an intermediate phase, and finally, another upregulation, providing longer term stress tolerance. PGPB-priming activates plant defences in the form of induced systemic resistance (ISR), often via the MAMP/MAPK pathways and involving one or more of the major plant hormone-signalling pathways and their crosstalk. Following PGPB-priming, the TFs families most commonly reported as expressed across different plants and for different pathogens are ERF and WRKY, while the TFs most commonly expressed across different plants for different abiotic stresses are ERF and DREB. There were inconsistencies between studies regarding the timing of the shift from the initial phase to the intermediate phase, and some of the TFs expressed during this process have not been fully characterized. This calls for more research to investigate the regulatory functions and phases of TF expression, to enhance crop resilience. Most reports on abiotic stresses have focused on salinity and drought, with fewer studies addressing nutrient deficiency, heavy metals, flooding, and other stresses, highlighting the need for further research in these areas.

Understanding the differential impact of PFOS and F-53B pollution on reed-mediated soil organic matter decomposition: Insights from rhizosphere priming effect.

Plants affect soil microorganisms through the release of root exudates under pollution stress. This process may affect rhizosphere priming effect (RPE) and alter the rate of soil organic matter decomposition. However, the influence of plants on the decomposition of organic matter in soil subjected to pollution stress remains unclear. We studied the effects of exposure to perfluorooctanesulfonic (PFOS) and its alternative, chlorinated polyfluoroalkyl ether sulfonic (F-53B), at concentrations of 0.1 mg/kg and 50 mg/kg on the RPE of reed. We conducted our experiments in an artificial climate chamber and used the natural 13C tracer method to determine RPE. In the PFOS-exposed groups, the RPE was negative, with values of -11.45 mg C kg-1 soil d-1 in the low PFOS group and -8.04 mg C kg-1 soil d-1 in the high PFOS group. In contrast, in the F-53B-exposed groups, the RPE was positive, with values of 8.26 mg C kg-1 soil d-1 in the low F-53B group and 12.18 mg C kg-1 soil d-1 in the high F-53B group. Exposure of reeds to PFOS/F-53B stress resulted in differential effects on extracellular enzyme activities. The observed positive and negative RPE phenomena could be attributed to variations in extracellular enzyme activities. In conclusion, RPE responded differently under PFOS/F-53B exposure.

Lexically-specific syntactic restrictions in second-language speakers.

In two structural priming experiments, we investigated the representations of lexically-specific syntactic restrictions of English verbs for highly proficient and immersed second language (L2) speakers of English. We considered the interplay of two possible mechanisms: generalization from the first language (L1) and statistical learning within the L2 (both of abstract structure and of lexically-specific information). In both experiments, L2 speakers with either Germanic or Romance languages as L1 were primed to produce dispreferred double-object structures involving non-alternating dative verbs. Priming occurred from ungrammatical double-object primes involving different non-alternating verbs (Experiment 1) and from grammatical primes involving alternating verbs (Experiment 2), supporting abstract statistical learning within the L2. However, we found no differences between L1-Germanic speakers (who have the double object structure in their L1) and L1-Romance speakers (who do not), inconsistent with the prediction for between-group differences of the L1-generalization account. Additionally, L2 speakers in Experiment 2 showed a lexical boost: There was stronger priming after (dispreferred) non-alternating same-verb double object primes than after (grammatical) alternating different-verb primes. Such lexically-driven persistence was also shown by L1 English speakers (Ivanova et al., 2012a) and may underlie statistical learning of lexically-dependent structural regularities. We conclude that lexically-specific syntactic restrictions in highly proficient and immersed L2 speakers are shaped by statistical learning (both abstract and lexically-specific) within the L2, but not by generalization from the L1.

Microplastic contamination accelerates soil carbon loss through positive priming.

The priming effect, i.e., the changes in soil organic matter (SOM) decomposition following fresh organic carbon (C) inputs is known to influence C storage in terrestrial ecosystems. Microplastics (particle size <5 mm) are ubiquitous in soils due to the increasing use and often inadequate end-of-life management of plastics. Conventional polyethylene and bio-degradable (PHBV) plastics contain large amounts of C within their molecular structure, which can be assimilated by microorganisms. However, the extent and direction of the potential priming effect induced by microplastics is unclear. As such, we added 14C-labeled glucose to investigate how background polyethylene and PHBV microplastics (1 %, w/w) affect SOM decomposition and its potential microbial mechanisms in a short-term. The cumulative CO2 emission in soil contaminated with PHBV was 42-53 % higher than under Polyethylene contaminated soil after 60-day incubation. Addition of glucose increased SOM decomposition and induced a positive priming effect, as a consequence, caused a negative net soil C balance (-59 to -132 µg C g-1 soil) regardless of microplastic types. K-strategists dominated in the PHBV-contaminated soils and induced 72 % higher positive priming effects as compared to Polyethylene-contaminated soils (160 vs. 92 µg C g-1 soil). This was attributed to the enhanced decomposition of recalcitrant SOM to acquire nitrogen. The stronger priming effect associated in PHBVs can be attributed to cooperative decomposition among fungi and bacteria, which metabolize more recalcitrant C in PHBV. Moreover, comparatively higher calorespirometric ratios, lower substrate use efficiency, and larger enzyme activity but shorter turnover time of enzymes indicated that soil contaminated with PHBV release more energy, and have a more efficient microbial catabolism and are more efficient in SOM decomposition and nutrient resource uptake. Overall, microplastics, (especially bio-degradable microplastics) can alter biogeochemical cycles with significant negative consequences for C sequestration via increasing SOM decomposition in agricultural soils and for regional and global C budgets.