Culture Experiments Research Articles

Exploring the Use of Water-Extracted Flaxseed Hydrocolloids in Three-Dimensional Cell Culture.

Plant-derived hydrocolloids offer promising prospects in biomedical applications. Among these, Flaxseed hydrocolloid (FSH) can form a soft, elastic, and biocompatible hydrocolloid with tunable viscosity and superior swelling capacity, making it an attractive scaffold. This study introduces a green extraction method for FSH, employing a single-step aqueous extraction process and fabrication of FSH scaffold. Despite growing interest, the pristine form of FSH has not been investigated for sustainable long-term three-dimensional (3D) cell culture. Here, FSH scaffolds were thoroughly characterized for their morphological, chemical, mechanical, and biological properties. 3D cell culture experiments were conducted using NIH-3T3 mouse fibroblast cells, and cell viability was assessed using live/dead and Alamar Blue assays. High cell viability was sustained for long term compared with 2D cell culture. Cell adhesion and 3D cellular morphology on FSH scaffold for 30 days were monitored by scanning electron microscopy analysis. Also, collagen type-I and F-actin expressions were analyzed by immunostaining after 30 days of culture, resulting in 5- and 4-fold increments of fluorescence intensity, respectively. Results indicate sustained cell viability in the long term and favorable cell-material interaction, demonstrating the potential of FSH as a scaffold. This study emphasizes the importance of the green extraction approach, improving the biocompatibility and functionality of FSH tissue engineering applications.

Optimizing Cowpea Cultivation in Saline Hydromorphic Soils: A Sustainable Approach for Kaipad Agroecosystems

Kaipad lands, a distinct coastal agro-ecosystem located in northern Malabar, Kerala, are characterized by saline-prone hydromorphic soils that pose significant challenges for traditional rice cultivation. The unique conditions of periodic waterlogging and salinity necessitate the exploration of alternative crops to enhance agricultural sustainability. This study investigates the suitability of cowpea (Vigna unguiculata L Walp) as a resilient leguminous crop for cultivation in traditionally organic rice growing problematic soils. Cowpea, known for its adaptability to diverse environmental conditions, nutritional value, and economic importance, presents a promising option for farmers facing the limitations of organic rice production. A pot culture experiment was conducted to assess the impact of potassium solubilizing bacteria (KSB) on cowpea growth and yield in saline hydromorphic soils. Treatments included combinations of KSB with various potassium sources, such as feldspar and mica, used as alternate sources for potassic fertilizers. Results demonstrated that KSB significantly improved growth parameters, including plant height, leaf area, total dry matter production, and pod and grain yields, compared to control. Soil analysis revealed enhanced availability of potassium and other essential nutrients in KSB-treated soils, indicating a synergistic effect on nutrient solubilization in aerobic conditions. The findings suggest that cowpea, supported by KSB application, can be effectively cultivated in problematic Kaipad lands, offering a viable alternative to traditional rice farming while promoting sustainable agricultural practices. This research highlights the potential for diversifying crop production in saline-prone areas, ultimately contributing to food security and economic resilience in coastal agro-ecosystems.

Evaluation of root morphology in banana genotypes under sodic soil stress using RhizoVision software

Banana (Musa spp.) productivity is limited by sodic soils, which impairs root growth and nutrient uptake. Analyzing root traits under stress conditions can aid in identifying tolerant genotypes. This study investigates the root morphological traits of banana cultivars under sodic soil stress conditions using Rhizovision software. The pot culture experiment was laid out in a Completely Randomized Design (CRD) under open field conditions, with treatments comprising the following varieties: Poovan (AAB), Udhayam (ABB), Karpooravalli (ABB), CO 3 (ABB), Kaveri Saba (ABB), Kaveri Kalki (ABB), Kaveri Haritha (ABB), Monthan (ABB), Nendran (AAB), and Rasthali (AAB), each replicated thrice. Parameters such as the number of roots, root tips, diameter, surface area, perimeter, and volume were assessed to evaluate the performance of different cultivars. The findings reveal that Karpooravali and Udhayam cultivars exhibited superior performance in terms of root morphology compared to other cultivars under sodic soil stress. These cultivars displayed increased root proliferation, elongation, and surface area, indicating their resilience to sodic soil stress. The utilization of Rhizovision software facilitated precise measurement and analysis of root traits, providing valuable insights into the adaptation mechanisms of banana cultivars to adverse soil conditions.

Impact of Carbon Dioxide Levels on Biochemical Parameters Associated with Stem Rot Disease in Groundnut

Background: Sclerotium rolfsii is a widespread soil-borne fungal pathogen recognized for causing disease in a wide variety of agricultural and horticultural crops globally. Despite the economic losses attributed to this pathogen, there are limited reports concerning the biochemical alterations in groundnut in response to increased carbon dioxide levels and pathogen interactions. Methods: A pot culture experiment was carried out at ICRISAT during the rabi season 2022-23 in Open Top Chambers (OTC) to assess the biochemical responses of groundnut to climate change and pathogen interactions. The study was carried out at three different carbon dioxide levels (400 ppm, 550 ppm and 700 ppm) using the susceptible groundnut cultivar TMV 2 and the moderately resistant cultivar ICGV-14082. Result: The levels of total phenols, oxalic acid, ascorbic acid, catalase, peroxidases, polyphenol oxidase, and chlorophyll content index were elevated in groundnut plants infected with stem rot due to increased carbon dioxide levels. The biochemical activity was high at its peak in inoculated plants on 4th and 6th day post-inoculation of the pathogen and gradually declined on 8th and 10th days.

Effects of Microplastic Pollution on Microbial Activity and Carbon Metabolism Function in Soil

Clarifying the ecological effects of microplastics （MPs） in soil is a frontier problem in environmental science research. A 60-d microcosmic culture experiment was conducted using soil with three relative abundances （2%, 5%, and 10%, MPs/soil）, of traditional MPs polystyrene （PS） and biodegradable MPs polylactic acid （PLA）. Additionally, the changes in microbial activity and carbon metabolism function in the soil after cultivation were analyzed. The results showed that： After cultivation with MPs, the soil pH decreased and the content of dissolved organic carbon （DOC） in the soil significantly increased. The addition of MPs significantly reduced the activities of catalase and polyphenol oxidase in the soil and the reduction degree was related to the concentration of MPs. However, the addition of PLA significantly enhanced the activity of soil urease, while PS had no significant effect on urease activity. The addition of MPs led to a decrease in the carbon metabolism ability of soil microbial communities. The carbon metabolism ability of soil microorganisms cultured with PS was higher than that of those cultured with PLA. The inhibitory effect of both on soil carbon metabolism was positively correlated with their concentration. The concentrations of PS （10%） and PLA （10%） had the strongest inhibitory effect on soil microbial carbon metabolism ability, with a decrease of 63.91% and 82.27%, respectively. PLA had a greater impact on soil microbial activity and carbon metabolism than that of PS because PLA in soil degraded easily to produce harmful dissolved organic matter and smaller plastic particles. The research results provide a theoretical basis for clarifying the ecological effects of MPs in soil and basic data for future development of standards related to soil MPs pollution.

Effects of Mercury Pollution on Soil Organic Carbon Stability and Carbon-fixing Microbial Communities

To elucidate the effects of Hg pollution on soil organic carbon stability and autotrophic microbial carbon assimilation, the characteristics of soil CO2 emission rate, organic carbon components, and cbbL and cbbM functional microorganisms before and after 29 d of Hg pollution were studied using indoor culture experiments and molecular biology techniques. The results showed that the effects of different levels of Hg pollution on soil CO2 emission rates were different. High levels of Hg （S2,S3,and S5） inhibited soil CO2 cumulative emissions, whereas low levels of Hg （S1,S4,and S6） promoted soil carbon emissions. Hg pollution affected the proportion of soil organic carbon components. The changes in SOC and MBC contents in different treatments were basically the same, with significant differences （P < 0.05）. EOC and DOC decreased with the increase in Hg content. Compared with that at 1 d, the qCO2 of each treatment was significantly decreased at the end of culture （P < 0.05）. The effects of different levels of Hg pollution on the functional microbial communities of cbbL and cbbM were significantly different. Proteobacteria, Actinobacteria, and Acidobacteria were the dominant phyla shared by the two functional microorganisms. Cumulative soil CO2 emissions and SOC were the main factors affecting the change in the cbbL community, and soil available Hg was the main factor affecting the change in the cbbM community. In summary, the results of this study can provide a theoretical basis for the carbon cycle and accumulation of Hg-contaminated regional ecosystems.

Characterization and inhibition of hydrogen sulfide-producing bacteria from petroleum reservoirs subjected to alkali-surfactant-polymer flooding.

Alkali-surfactant-polymer (ASP) flooding is an emerging and promising oil recovery technique. However, the methods for preventing hydrogen sulfide-producing bacteria (SPB), chief culprits to microbial souring, in such alkali reservoirs remains unknown. Here, four alkaline-tolerant SPB exhibiting versatile sulfur metabolism were identified. Representative strains DS3, DS5, DS8, and DS23 were affiliated with Sulfurospirillum alkalitolerans, Desulfonatronovibrio hydrogenovorans, Desulfobotulus sapovorans, and Desulfovibrio alkalitolerans, respectively. Pure culture experiments showed nitrite exerted partial inhibitory effects since DS3 preferred nitrite as an electron acceptor. And nitrate inhibition was feeble, as nitrate was dissimilated to ammonium by DS3 and DS5, and DS8 preferentially utilized sulfate compared with nitrate, and DS23 ignored nitrate respiration. Glutaraldehyde effectively prevented the production of H2S in pure culture and microcosmic simulation system, demonstrating its practical application potential in alkali reservoirs. This study enhances the understanding on physiological characteristics of SPB and bridges the gap in souring management in high alkaline ASP-flooded reservoirs.

Gut-Microbiota-Derived Butyric Acid Overload Contributes to Ileal Mucosal Barrier Damage in Late Phase of Chronic Unpredictable Mild Stress Mice

Intestinal mucosal barrier damage is regarded as the critical factor through which chronic unpredictable mild stress (CUMS) leads to a variety of physical and mental health problems. However, the exact mechanism by which CUMS induces intestinal mucosal barrier damage is unclear. In this study, 14, 28, and 42 d CUMS model mice were established. The indicators related to ileal mucosal barrier damage (IMBD), the composition of the ileal microbiota and its amino acid (AA) and short-chain fatty acid (SCFA) metabolic functions, and free amino acid (FAA) and SCFA levels in the ileal lumen were measured before and after each stress period. The correlations between them are analyzed to investigate how CUMS induces intestinal mucosal barrier damage in male C57BL/6 mice. With the progression of CUMS, butyric acid (BA) levels decreased (14 and 28 d) and then increased (42 d), and IMBD progressively increased. In the late CUMS stage (42 d), the degree of IMBD is most severe and positively correlated with significantly increased BA levels (p < 0.05) in the ileal lumen and negatively correlated with significantly decreased FAAs, such as aspartic, glutamic, alanine, and glycine levels (p < 0.05). In the ileal lumen, the abundance of BA-producing bacteria (Muribaculaceae, Ruminococcus, and Butyricicoccus) and the gene abundance of specific AA degradation and BA production pathways and their related enzymes are significantly increased (p < 0.05). In addition, there is a significant decrease (p < 0.05) in the abundance of core bacteria (Prevotella, Lactobacillus, Turicibacter, Blautia, and Barnesiella) that rely on these specific AAs for growth and/or are sensitive to BA. These changes, in turn, promote further colonization of BA-producing bacteria, exacerbating the over-accumulation of BA in the ileal lumen. These results were validated by ileal microbiota in vitro culture experiments. In summary, in the late CUMS stages, IMBD is related to an excessive accumulation of BA caused by dysbiosis of the ileal microbiota and its overactive AA degradation.

The effects of temperature and CO2 enrichment on the red seaweed Asparagopsis taxiformis from Southern California with implications for aquaculture.

The red alga Asparagopsis taxiformis has recently been recognized for its unique ability to significantly reduce methane emissions from ruminant animals when fed in small quantities. The main obstacle in using this seaweed as a methane-mitigating feed supplement is the lack of commercially available biomass. Little is known about how best to grow this red alga on a commercial scale, as there are few published studies that have investigated the factors that influence growth, physiology, and overall performance. This study examined the effects of temperature and CO2 enrichment on the growth, photophysiology, and concentration of bromoform, the secondary metabolite largely responsible for methane reduction in A. taxiformis. A series of single and multifactor closed culture experiments were conducted on A. taxiformis collected, isolated, and cultured from populations in Southern California. We identified the optimal temperature range to be between 22 and 26°C, with significant short-term stress observed below 15°C and above 26°C. Carbon dioxide addition resulted in increased performance, when accounting for growth per CO2 use. In general, we observed the highest bromoform concentrations in algae with the highest growth rates, but these results varied among experiments. These findings indicate that through environmental control and by addressing limiting resources, significant increases in biomass production and quality can be achieved.

Synergistic integration of plant derived galactomannan and MXene to produce multifunctional nanocomposites with antibacterial and osteogenic properties

This study proposes to combine plant-derived galactomannan and MXene to form an organic-inorganic hydrogel network with integrative antibacterial and osteogenic properties. Oxidized galactomannan (OxGa) was blended with N-succinyl chitosan (NSC) and varying concentrations of Mxene, owing to its high reactivity and biocompatibility. The results indicated that Mxene-loaded OxGa/NSC scaffolds exhibited biomimetic topography, adequate mechanical features and excellent physicochemical properties with strong antibacterial properties against pathogenic microbes. The cell culture experiments showed dose-dependent cytotoxic behaviour. An optimized MXene content of ≤ 4 mg/ml revealed no cytotoxicity and augmented the proliferation of osteoblast cells. Similar results were obtained in gene expression analysis where ALP, COL1A1, RUNX2, and SOX2 genes showed up-regulation. In addition, the chorioallantoic membrane (CAM) assay also illustrated augmentation of angiogenesis without any toxicity. The overall results highlight the dual performance of OxGa/NSC-MXene scaffolds to exhibit anti-infection with simultaneous osteogenic properties, which is purely determined by the concentration of MXene. Therefore, regulating MXene concentration can serve as a chemical switch in imparting adequate antibacterial functions with the ability to allow new osseous generation. Our findings on the newly designed Mxene-loaded OxGa/NSC scaffolds can be a promising biomaterial for bone-related infections with a concurrent ability to promote osteogenesis.

Insight into the Simultaneous Super-Stable Mineralization of AsO4 3-, Cd2+ and Pb2+ Using MgFe-LDHs.

Multiple-heavy-metal contamination in soil, such as the simultaneous presence of AsO4 3-, Cd2+ and Pb2+, which can reduce crop yields and damage human health, is a serious issue to be addressed. Herein, the MgFe-LDHs (layered double hydroxides) intercalated with carbonate and nitrate (MgFe-CO3 and MgFe-NO3) were synthesized by Separate Nucleation and Aging Steps and ion-exchange method, respectively. The MgFe-CO3 demonstrated the maximum saturation adsorption capacity of 55.86, 543.48 and 1597.4 mg g-1 for single AsO4 3-, Cd2+ and Pb2+ in aqueous solution, while MgFe-NO3 exhibited 92.50, 387.59 and 869.56 mg g-1, respectively. Kinetic and thermodynamic results for mineralization of single AsO4 3-, Cd2+ and Pb2+ fitted well with the pseudo-second-order kinetic model and Langmuir isotherm model, indicating the occurrence of chemisorption and monolayer adsorption for both MgFe-CO3 and MgFe-NO3. Furthermore, simultaneous mineralization of AsO4 3-, Cd2+ and Pb2+ with >99.0 % efficiency in 240 min in aqueous solution and >81.1 % efficiency in 14 days in soil can be achieved by both MgFe-CO3 and MgFe-NO3. Preliminary red bean seedlings cultivation experiments indicated that the released Mg2+ ions from MgFe-CO3 and MgFe-NO3 were capable to promote the emergence and growth of red bean seedlings. Detailed XRD and XPS results demonstrated that the AsO4 3- anions were adsorbed on the laminate of LDHs, whereas the Pb3(OH)2(CO3)2 was the mineralization product for both MgFe-CO3 and MgFe-NO3. In terms of Cd2+, CdCO3 was obtained as a mineralization product for MgFe-CO3, while CdCO3 and Cd(OH)2 can be detected due to the slow transformation of MgFe-NO3 to MgFe-CO3 in air.

Microbial response to deliquescence of nitrate-rich soils in the hyperarid Atacama Desert

Abstract. Life in hyperarid regions has adapted to extreme water scarcity through mechanisms like salt deliquescence. While halite (NaCl) crusts have been intensively studied and identified as one of the last habitats under hyperarid conditions, other less common hygroscopic salt crusts remain unexplored. Here, we investigated newly discovered deliquescent soil surfaces in the Atacama Desert, containing substantial amounts of nitrates, to evaluate their habitability for microorganisms. We characterized the environment with respect to water availability and biogeochemistry. Microbial abundances and composition were determined by cell cultivation experiments, 16S rRNA gene sequencing, and membrane phospholipid fatty acid (PLFA) analysis, while microbial activity was assessed by analyzing adenosine triphosphate (ATP) and the molecular composition of organic matter. Our findings reveal that, while the studied hygroscopic salts provide temporary water, microbial abundances and activity are lower in the studied soil surfaces than in non-deliquescent soil surfaces. Intriguingly, the deliquescent crusts are enriched in geochemically degraded organic matter, indicated by the molecular composition. We conclude that high nitrate concentrations in the hyperarid soils suppress microbial activity but preserve eolian-derived biomolecules. These insights are important for assessing the habitability and searching for life in hyperarid environments on Earth and beyond.

RNA programmable cell targeting and manipulation with CellREADR.

Methods that provide specific, easy, and scalable experimental access to animal cell types and cell states will have broad applications in biology and medicine. CellREADR - Cell access through RNA sensing by Endogenous ADAR (adenosine deaminase acting on RNA), is a programmable RNA sensor-actuator technology that couples the detection of a cell-defining RNA to the translation of an effector protein to monitor and manipulate the cell. The CellREADR RNA device consists of a 5' sensor region complementary to a cellular RNA and a 3' payload coding region; payload translation is gated by the removal of a STOP codon in the sensor region upon base pairing with the cognate cellular RNA through an ADAR-mediated A- to-I editing mechanism ubiquitous to metazoan cells. CellREADR thus highlights the potential for RNA-based monitoring and manipulation of animal cells in ways that are simple, versatile, and generalizable across tissues and species. Here, we describe a detailed protocol for implementing CellREADR experiments in cell cultures and in animals. The procedure includes sensor and payload design, cloning, validation and characterization in mammalian cell cultures. The in vivo animal protocol focuses on AAV-based delivery of CellREADR using brain tissue as examples. We describe current best practices, various experimental controls and trouble-shooting steps. Beginning from sensor design, the validation of RNA sensor-actuators in cell cultures can be completed in 2-3 weeks. The construction of AAV vectors and their in vivo validation and characterization will take additional 6-8 weeks.

Structural and Mechanistic Bases for Resistance of the M66I Capsid Variant to Lenacapavir.

Lenacapavir (LEN) is a highly potent and long-acting antiretroviral that works by a unique mechanism of targeting the viral capsid protein. The inhibitor is used in combination with other antiretrovirals to treat multi-drug-resistant HIV-1 infection in heavily treatment-experienced adults. Furthermore, LEN is in clinical trials for preexposure prophylaxis (PrEP) with interim results indicating 100 % efficacy to prevent HIV-1 infections. However, one notable shortcoming is a relatively low barrier of viral resistance to LEN. Clinical trials and cell culture experiments identified emergent resistance mutations near the inhibitor binding site on capsid. The M66I variant was the most prevalent capsid substitution identified in patients receiving LEN to treat muti-drug resistant HIV-1 infections. The studies described here elucidate the underlying mechanism by which the M66I substitution confers a marked resistance to the inhibitor. Furthermore, our structural findings will aid future efforts to develop the next generation of capsid inhibitors with enhanced barriers to resistance.

Synergy of biochar and biofertilizers to improve bell pepper fruit biochemical quality with increased soil carbon, Azospirillum population and mycorrhization

Sustainable crop production depends more on maintaining good soil health. Biochar significantly improves the soil's physical, chemical, biological and nutritional properties while aiding in carbon sequestration. Biofertilizers, which promote nutrient cycling, heavy metal chelation and the production of plant growth substances are crucial to sustainable agriculture. While the individual benefits of biochar and biofertilizers are well-documented, their combined effect in vegetable farming is less studied. The synergistic application of biochar and biofertilizers can improve soil health and nutrient dynamics, enhancing crops' biochemical properties. In a pot culture experiment, California Wonder bell peppers were treated with biochar and biofertilizers, including Azospirillum, Vesicular Arbuscular Mycorrhiza (VAM), and Serendipita indica. These were applied directly to the soil during transplanting. Results showed that plants treated with biochar + Azospirillum had higher flavonoid, total soluble protein and ascorbic acid content. Biochar + VAM treatment resulted in higher polyphenol content, total dry matter and root volume. S. indica reduced the vegetative period and induced earlier flowering. Biochar also increased soil organic carbon (2.89 %), improved the rhizosphere Azospirillum population and enhanced fungal endophytes' root colonization. Combining biochar and biofertilizer improves bell pepper plant performance, enhances biochemical parameters and improves soil health.

Finerenone attenuates downregulation of the kidney GLP-1 receptor and glucagon receptor and cardiac GIP receptor in mice with comorbid diabetes

BackgroundSeveral new treatments have recently been shown to have heart and kidney protective benefits in people with diabetes. Because these treatments were developed in parallel, it is unclear how the different molecular pathways affected by the therapies may overlap. Here, we examined the effects of the mineralocorticoid receptor antagonist finerenone in mice with comorbid diabetes, focusing on the regulation of expression of the glucagon-like peptide-1 receptor (GLP-1R), gastric inhibitory polypeptide receptor (GIPR) and glucagon receptor (GCGR), which are targets of approved or investigational therapies in diabetes.MethodsMale C57BL/6J mice were fed a high fat diet for 26 weeks. Twelve weeks into the high fat diet feeding period, mice received an intraperitoneal injection of streptozotocin before being followed for the remaining 14 weeks (DMHFD mice). After 26 weeks, mice were fed a high fat diet containing finerenone (100 mg/kg diet) or high fat diet alone for a further 2 weeks. Cell culture experiments were performed in primary vascular smooth muscle cells (VSMCs), NRK-49 F fibroblasts, HK-2 cells, and MDCK cells.ResultsDMHFD mice developed albuminuria, glomerular mesangial expansion, and diastolic dysfunction (decreased E/A ratio). Glp1r and Gcgr were predominantly expressed in arteriolar VSMCs and distal nephron structures of mouse kidneys respectively, whereas Gipr was the predominant of the three transcripts in mouse hearts. Kidney Glp1r and Gcgr and cardiac Gipr mRNA levels were reduced in DMHFD mice and this reduction was negated or attenuated with finerenone. Mechanistically, finerenone attenuated upregulation of the profibrotic growth factor Ccn2 in DMHFD kidneys, whereas recombinant CCN2 downregulated Glp1r and Gcgr in VSMCs and MDCK cells respectively.ConclusionsThrough its anti-fibrotic actions, finerenone reverses Glp1r and Gcgr downregulation in the diabetic kidney. Both finerenone and GLP-1R agonists have proven cardiorenal benefits, whereas receptor co-agonists are approved or under development. The current findings provide preclinical rationale for the combined use of finerenone with the GLP-1R agonist family. They also provide mechanism of action insights into the potential benefit of finerenone in people with diabetes for whom GLP-1R agonists or co-agonists may not be indicated.

Impact of glyphosate on soil bacterial communities and degradation mechanisms in large-leaf tea plantations

This study investigated the impact of glyphosate on bacterial communities and their degradation mechanisms in large-leaf tea soil, through exposure microcosm and enrichment culture experiments. Soils from three tea gardens in Yunnan, China, were used: two glyphosate-free (JM and KL) for microcosm study and one long-term exposed (G2) for enrichment culture experiment. The results revealed a two-phase degradation process with half-lives of 12.7 to 268 days, while the metabolite AMPA was notably persistent. The acidic conditions and high organic content of tea soils may retard glyphosate microbial availability and degradation. Glyphosate initially stimulated bacterial growth but led to abundance declines with prolonged exposure. It tended to enhance bacterial diversity at lower doses. Network complexity increased in JM soil where strong adsorption moderated glyphosate exposure, yet decreased in KL soil where weak adsorption enabled greater microbial-glyphosate interactions. Community structure analysis revealed soil-specific responses, with decreased Proteobacteria in JM soil and Actinobacteria in KL soil, while several phyla including Proteobacteria, Acidobacteriota, Chloroflexi, Myxococcota, and Verrucomicrobiota showed increased abundance. PICRUSt2 analysis indicated enhanced biosynthesis and cell growth pathways, while carbohydrate metabolism, nitrogen metabolism, and xenobiotics biodegradation pathways were reduced. LEfSe analysis identified potential degrading biomarkers primarily from Proteobacteria, Acidobacteriota, Myxococcota, Chloroflexi, and Actinobacteriota, suggesting their putative role in degradation. The enriched consortium G2 efficiently degraded 400mg/L glyphosate within 7 days, with notable increases in Afipia, Dokdonella, and Cohnella abundance. This study provides insights into bacterial interactions with glyphosate in tea soils, suggesting strategies for contamination mitigation and environmental restoration.

Sulfur redirects carbon metabolism to optimize nitrogen utilization and promote andrographolide biosynthesis in Andrographis paniculata seedlings

Sulfur (S) is an important mineral nutrient element that improves plant growth and secondary metabolism. S affects the biosynthesis of andrographolide in medicinal plant Androgaphis paniculata by regulating nitrogen (N) metabolism. However, its specific role in N utilization and the connection with andrographolide biosynthesis have not yet been thoroughly understood. Here, a soilless cultivation experiment with low S (LS, 0.1 mM) and high S (HS, 2.4 mM) was conducted to investigate how S influences carbon (C) metabolism and N utilization to promote andographolide biosynthesis in Andrographis paniculata. The results showed that HS significantly increased plant biomass and N use efficiency (NUE), accompanying with remarkable enhanced andrographolide content. HS promoted the expression of photosynthetic genes, and redirected C metabolism towards to sugars accumulation by enhancing the activities of NAD-dependent glutamate dehydrogenase (NAD-GDH), malic enzyme (ME) and phosphoenolpyruvate carboxykinase (PEPCK) (P < 0.05). On the other hand, HS reduced N and S assimilation, and stimulated a greater N allocation in photosynthesis. Accordingly, NUE was increased and andrographolided biosynthesis could profit from the shift of C resource reallocation. Additionally, the significantly increased activities of ME, glucose 6-phosphate dehydrogenase (G6PDH) and isocitrate dehydrogenase (ICDH) provided reductants for secondary metabolism. HS also considerably upregulated the expression of genes in andrographolide biosynthetic pathway, including ApDXS, ApDXR, ApHDS and ApHDR in the MEP pathway, and ApGGPS. Transcription factors in the families of MYB, WRKY, ERF and bHLH, and plant hormones ABA and JA were in response to HS. Our results revealed that S synergistically promotes NUE and andrographolide biosynthesis via remodeling of C metabolism in A. paniculata.

Influence of seed-applied biostimulants on soybean germination and early seedling growth under low and high temperature stress

AbstractBiostimulants are environment-friendly agricultural inputs that can improve plant health and yield potential under environmental stressors. Soybeans subjected to extreme temperatures during the growing seasons impacts plant health and performance. Uniform emergence and vigorous seedling establishment are the two traits during the early season that directly correlate with the final yield and are sensitive to abiotic stress. This study tested the effectiveness of seed-applied biostimulants in improving seed germination and emergence traits under different temperatures, low (15 °C, LT), optimum (25 °C, OT), and high (35 °C, HT), using three phenotyping methods such as the paper roll, growth pouch, and soil-based pot culture. Germination, emergence, and seedling growth were significantly accelerated under OT and HT compared to LT in both biostimulant-treated and untreated seeds. While seeds treated with biostimulants exhibited minor differences in germination, emergence, and growth traits under LT and HT compared to the OT. In the soil-based pot culture experiment, humic and fulvic acid-containing treatments extended the time to 50% emergence under LT. This delay was associated with a 13% increase in seedling biomass. A bacillus containing biostimulant improved seedling vigor by 7% under LT compared to untreated check. Notably, biostimulants containing bacterial strains, fulvic acid, and humic acid were found to have a role in reducing time to germination or emergence and enhancing seedling growth. However, the results obtained from different phenotyping methods were inconsistent, suggesting that the effects of biostimulants on germination and growth parameters may be more targeted rather than broad-spectrum. Future research is necessary to optimize application rates and fully explore their potential to mitigate the effects of stressors during the growing season.

Sustainable dual-cathode photoelectro-Fenton-like system at a wide pH range for rapid degradation of emerging pollutants

In-situ Fenton like process was highly promising and energy-efficient for treating emerging organic contaminants. However, the challenge in the production and activation of H2O2 faces its practical application. Herein, a photoelectro-Fenton-like (PEF) system was successfully fabricated with BiVO4 thin-film, graphite (C) and PhC2Cu as photoanode, cathode and photocathode, respectively. The ternary system was applied for visible-light degradation of Tetracycline (TC) at a low potential of 0.5 V. H2O2 was generated at the graphite cathode and then activated to produce •OH by Cu(I) from PhC2Cu photocathode. The photo-generated electrons accelerated the Cu(I)/Cu(II) cycle to achieve sustainable PEF reactions. After 150 min of illumination, 97 % TC was degraded in BiVO4|C|PCu system, superior to BiVO4|C and BiVO4|PCu systems. The outstanding stability and reusability of this PEF system was proved by 10 cycles. Moreover, the vulnerable atomic sites of TC molecule were predicated by the Fukui function. Both inhibition zone tests of bacteria and wheat seeds cultivation experiments proved that the constructed PEF system displayed outstanding performance in hampering TC eco-toxicity. For example, the Fv/Fm fluorescence image map demonstrated that the constructed PEF system not only degraded organic pollutants but also lowered their toxicity. Finally, the mechanism of in-situ generation and activation of H2O2 was proposed based on the results of quenching experiments, PL spectra and ESR technique. Overall, this study provides a promising pathway to remediate environmental pollution through constructing a PEF system based on dual cathodes.