Search Results (33)

Antibiotic resistance genes (ARGs) are becoming a global issue due to the emergence of superbugs. However, the impact of elevated CO₂ (eCO₂) on the soil antibiotic resistome remains largely unknown. Here, using a free-air CO₂ enrichment platform, we employed high-throughput quantitative PCR and 16S rRNA gene sequencing to investigate the effect of eCO₂ (ambient + 200 ppm) on soil ARGs and bacterial communities in a paddy ecosystem at harvest. The results showed that eCO₂ had no significant effect on rice biomass. A LEfSe analysis identified a clear taxonomic shift, with taxa such as c_Clostridia, g_Dehalobacter and g_Syntrophus being significantly enriched under eCO₂. The total relative abundance of ARGs increased 1.5-fold under eCO₂, driven by a 2.8-fold increase in multidrug resistance genes. The correlation and network analyses revealed that the proliferation of specific potential host bacteria was the primary driver of the observed ARG enrichment under eCO₂. Together, this study offers new insights into the eCO₂-driven alterations of soil antibiotic resistomes, highlighting the elevated dissemination potential of multidrug resistance genes within paddy ecosystems and their potential implications for food safety. Full article

Copper is an essential trace element that supports numerous physiological functions; however, excessive copper accumulation can disrupt cellular and biological processes. In this study, forty-eight male mice were randomly divided into four groups (n = 12): Control (fed normal rice), Cu300 (300 mg/kg copper), Cu300+Se (Cu300 + selenium-enriched rice), and Cu300+iSe (Cu300 + 1 mg/kg iSe), and were treated for 180 days. Copper exposure resulted in reduced body weight, hepatomegaly and nephritis, elevated copper deposition in organs, oxidative stress, and significant declines in RBC, HGB, and WBC counts, leading to anemia and immunosuppression. Selenium supplementation, effectively mitigated these effects by reducing copper accumulation, restoring antioxidant balance, and enhancing selenoprotein-related functions. Histopathological analysis revealed that copper toxicity induced hydropic degeneration and focal necrosis in hepatic and renal tissues, effects that were significantly attenuated by selenium supplementation. Transcriptomic profiling revealed that selenium-enriched rice reversed copper-induced gene expression changes. In the liver, selenium treatment significantly upregulated protective genes such as Slc7a, Bola1, Uqcrq, Dtx1, and Znrd2, while downregulating stress-related genes like Trim75, Dpm3, Moxd1, Tnfrsf25, and Gpr75. In the kidneys, selenium enhanced the expression of detoxification and immune-modulating genes (Mt1, Mt2, Rhbdl1, Crisp3, Mif) and suppressed stress-related genes (Nnt, Ifi44l, NLRP12, Eno1b, Ugt1a), demonstrating its role in mitigating oxidative and inflammatory stress. Collectively, these findings demonstrate that selenium-enriched rice exerts potent protective effects against chronic copper toxicity through multiple mechanisms: (1) restoration of mitochondrial function, (2) attenuation of ER stress and apoptosis, (3) enhancement of antioxidant and detoxification pathways, and (4) modulation of metabolic and immune responses. This study highlights selenium-enriched rice as a promising nutritional intervention for mitigating chronic copper toxicity and maintaining hepatorenal health. Full article

To evaluate the effects of dietary threonine levels on rice field eels (Monopterus albus), six experimental diets were formulated with graded threonine supplementation: 0 g/kg (T1), 3 g/kg (T2), 6 g/kg (T3), 9 g/kg (T4), 12 g/kg (T5), and 15 g/kg (T6). Rice field eels, with an initial body weight of 18.47 ± 0.11 g, were fed for 60 days. The weight gain ratio (WGR), specific growth rate (SGR), and protein efficiency ratio (PER) significantly increased in the T4 group, while feed conversion ratio (FCR) significantly decreased. Broken-line regression analysis determined the optimal dietary threonine requirement to be 7.5–9.0 g/kg. Concomitantly, whole-body crude protein content increased, while lipid content decreased; serum GOT and GPT activities declined, indicating reduced hepatic stress, whereas hepatic CAT and SOD activities markedly increased, enhancing antioxidant capacity. Digestive enzyme capacity was enhanced, as evidenced by elevated lipase and trypsin activities. Muscle texture properties, including cohesiveness, springiness, and chewiness, were significantly improved in the T4 and T5 groups. At the molecular level, MyoG, MyoD1, and MYF5 expression peaked in T4, while MRF4 expression increased progressively. LEfSe analysis of the microbiome, coupled with KEGG functional prediction, revealed that Corynebacterium and Methylocella were positively correlated with growth metrics; these genera likely promote muscle deposition through three enriched metabolic pathways that enhance energy and amino acid availability. Collectively, dietary threonine supplementation at 7.5–9.0 g/kg promotes growth, enhances digestive function, and improves muscle quality in rice field eels. Full article

With the growing global demand for rice and the urgent need to enhance sustainable production, ratoon rice systems and selenium (Se) biofortification technologies have become important strategies. This study investigated the effects of the foliar application of ethylenediaminetetraacetic acid Se (EDTA-Se) during key growth stages of the main rice season on the yield, grain quality, and Se accumulation in ratoon rice. Two rice varieties—Fengliangyouxiang-1 (FLYX1) and Jinliangyouhuazhan (JLYHZ)—were selected for a two-year field experiment. A systematic analysis was performed on yield components, processing quality, appearance quality, nutritional quality, and Se speciation. The results showed that under an equivalent total amount of spraying EDTA-Se, the best effect on improving the yield, grain quality, and grain Se content of ratoon rice was observed at the heading stage and seven days after full heading. This treatment increased ratoon season yield by 6.45%, primarily due to enhanced grain filling rate (GF) and spikelets per panicle (SP). Processing quality was significantly improved; milled rice rate (MR) increased by 5.59–6.24% in FLYX1 and 3.38–3.52% in JLYHZ, while appearance quality also improved, with chalky grain rate (CGR) decreasing by 21.51–22.93% in FLYX1 and 14.50–14.53% in JLYHZ. These improvements were closely associated with elevated protein content and increased accumulation of selenomethionine (SM). Notably, FLYX1 exhibited higher efficiency in converting selenium to organic forms, whereas JLYHZ showed a greater accumulation of inorganic selenium, highlighting genotype-specific responses. This study confirmed that the foliar application of EDTA-Se during key growth phases of rice during the main season can synergistically optimize yield and quality in ratoon rice while achieving Se biofortification and providing a theoretical basis and technical support for improving the quality and efficiency of ratoon rice, as well as producing Se-enriched ratoon rice. Full article

Soil salinization and selenium (Se) deficiency threaten global food security. This study developed a composite bioinoculant combining ACC deaminase-producing Serratia liquefaciens and biogenically synthesized nano-selenium (SeNPs) to alleviate saline–alkali stress and enhance Se nutrition in rice (Oryza sativa L.). A strain of S. liquefaciens with high ACC deaminase activity was isolated and used to biosynthesize SeNPs with stable physicochemical properties. Pot experiments showed that application of the composite inoculant (S3: S. liquefaciens + 40 mmol/L SeNPs) significantly improved seedling biomass (fresh weight +53.8%, dry weight +60.6%), plant height (+31.6%), and root activity under saline–alkali conditions. S3 treatment also enhanced panicle weight, seed-setting rate, and grain Se content (234.13 μg/kg), meeting national Se-enriched rice standards. Moreover, it increased rhizosphere soil N, P, and K availability and improved microbial α-diversity. This is the first comprehensive demonstration that a synergistic bioformulation of ACC deaminase PGPR and biogenic SeNPs effectively mitigates saline–alkali stress, enhances soil fertility, and enables safe Se biofortification in rice. Full article

Low temperature is a major abiotic stress affecting rice productivity. Selenium (Se) treatment has been shown to enhance plant resilience to cold stress. In this study, low concentrations of selenium (ColdSe1) alleviated the adverse effects of cold stress on rice seedlings, improving fresh weight, plant height, and chlorophyll content by 36.9%, 24.3%, and 8.4%, respectively, while reducing malondialdehyde (MDA) content by 29.1%. Se treatment also increased the activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), by 25.2%, 42.7%, and 33.3%, respectively, and upregulated flavonoids, soluble sugars, cysteine (Cys), glutathione (GSH), and oxidized glutathione (GSSG). Transcriptome analysis revealed that ColdSe1 treatment upregulated genes associated with amino and nucleotide sugar metabolism, glutathione metabolism, and fructose and mannose metabolism. It also alleviated cold stress by modulating the MAPK signaling pathway, phytohormone signaling, and photosynthesis-related pathways, enriching genes and transcription factors linked to antioxidant metabolism and photosynthesis. Metabolomic analyses showed that ColdSe1 positively influenced amino acid glucose metabolism, glycerolipid metabolism, hormonal pathways, and alanine/glutamate pathways under cold stress, while also upregulating metabolites associated with plant secondary metabolites (e.g., flavonoids, phenolic compounds) and antioxidant metabolism (e.g., α-linolenic acid metabolism). In contrast, high selenium concentrations (ColdSe2) disrupted phenylpropanoid biosynthesis, α-linolenic acid metabolism, and ABC transporter function, exacerbating cold-stress injury. This study highlights the critical role of Se in mitigating cold stress in rice, offering a theoretical basis for its application as an agricultural stress reliever. Full article

Cadmium (Cd) pollution in rice and selenium (Se) deficiency in humans have attracted widespread attention. In this study, we investigated the effects of the combined application of biological nanoselenium (B-SeNPs) foliar spray and biochar (BC) on Se enrichment and Cd content reduction in rice. A pot experiment was established by designing four levels each of BC and B-SeNPs to be applied to rice plants. The results revealed that soil Cd bioavailability decreased by 3.26–16.67%, while soil Se bioavailability increased by 0.76–7.63% in the combined BC and B-SeNPs treatments, with rice photosynthesis showing significant enhancement during each growth period. Both BC and B-SeNPs treatments significantly enhanced the levels of antioxidant components (glutathione, phytochelatins, catalase, peroxidase, and superoxide dismutase) while reducing oxidative stress markers (malondialdehyde and superoxide anion radical) in rice leaves. Additionally, these treatments effectively modulated the subcellular distribution of Se and Cd, demonstrating their potential in alleviating Cd toxicity and enhancing Se homeostasis. These changes were accompanied by a marked reduction in lipid peroxidation (indicated by malondialdehyde) and superoxide radical accumulation, suggesting that BC and B-SeNPs treatments strengthened the antioxidative defense system in rice leaves. Additionally, compared with the BC0Se0 treatment, the combined application of BC and B-SeNPs significantly enhanced grain Se content by 7.14–221.43% while significantly reducing Cd content by 30.77–76.92%. The efficacy of grain Se enrichment and Cd reduction followed the sequence B-SeNPs + BC > Se only > BC only, where the BC5Se20 treatment demonstrated the most pronounced effects on both Se accumulation and Cd decrease in grains. Therefore, the combined application of foliar-applied B-SeNPs and biochar not only reduces Cd bioavailability in soil but also effectively suppresses Cd uptake by rice while simultaneously enhancing Se enrichment. Full article

Selenium (Se) is essential for human health, but it interacts with cadmium (Cd). However, there has been little focus on developing soil health evaluation models based on the interaction between Se and heavy metals, or the transport of Se and Cd in oilseed rape. Through detection, it was found that the soil in Yuanzhou District is mostly Se-rich (average 0.62 mg kg⁻¹). Correlation analysis of the soil showed a positive correlation between Se content with Cd (r = 0.62, p < 0.01) and organic matter (r = 0.60, p < 0.01). A soil health score model was developed and performed well, indicating that the model can be used to estimate relevant soil health scores. Furthermore, the natural Se content of rice ranges from 0.07 to 0.28 mg kg⁻¹, and the overall enrichment ability of Se and Cd in oilseed rape is stronger than it is in rice. According to the correlation analysis, the Cd content in the soil was significantly correlated with the stems of oilseed rape (r = 0.49, p < 0.01) and rice (r = 0.37, p < 0.05). As a result, this study suggests using the rice/oilseed rape intercropping model of farming to transfer Cd into oilseed rape to reduce the Cd content in rice. Full article

Selenium (Se) is an essential trace element for humans, and the production of Se-enriched rice (Oryza sativa) is a key approach for Se supplementation. Nevertheless, the effects of different Se forms and concentrations on the metabolism and aboveground absorption pathways of rice seedlings are not yet well-understood. Therefore, we conducted a hydroponic experiment and used transcriptome analysis to study the absorption and transformation processes of sodium selenite (Na₂SeO₃) and selenomethionine (SeMet) in rice at the seedling stage. The aboveground (stem + leaf) Se concentration at the seedling stage was higher under the SeMet treatments, and low Se applications (<25 μM) significantly promoted rice growth. Selenocysteine (SeCys) and SeMet were the primary forms of Se in rice, accounting for 57–86.35% and 7.6–31.5%, respectively, while selenate [Se (VI)] significantly increased when Se levels exceeded 25 μM. In the transcriptome, differentially expressed genes (DEGs) were significantly enriched in the following pathways: carbon metabolism, amino acid biosynthesis, and glutathione metabolism. In the Na₂SeO₃ treatments, genes encoding phosphoglycerate mutase (PGM), triosephosphate isomerase (TPI), phosphofructokinase (PFK), pyruvate kinase (PK), malate dehydrogenase (MDH), polyamine oxidase (PAO), aspartate aminotransferase (AST), and glutathione S-transferase (GST) were upregulated, and the expression levels of differentially expressed genes (DEGs) decreased with increasing Se levels. SeMet treatments upregulated genes encoding PFK, PK, glutamine synthetase (NADH-GOGAT), and L-ascorbate peroxidase (APX), and expression levels of DEGs increased with increasing Se levels. This study provides important insights into the molecular mechanisms of the uptake and metabolism of different Se forms in rice at the seedling stage. Full article

Selenium (Se) is an essential micronutrient for the human body and is closely linked to health. Rice (Oryza sativa L.), as a major staple food globally, is the primary source of Se intake for humans. To better achieve Se biofortification in rice, it is crucial to understand the molecular mechanisms behind rice’s response to different Se concentrations. This study investigates the morphological and transcriptomic responses of rice seedlings to low (1 µM, LSe) and high (10 µM, HSe) Se concentrations compared to a control (CK). Morphological analyses revealed that LSe promoted growth, enhancing shoot and root length and biomass, whereas HSe treatment inhibited these parameters, indicating Se’s dual role in rice growth. Notably, the most significant promotion of rice growth was observed at the Se concentration of 1 µM. The organic Se content and antioxidant enzyme activities (SOD, POD and CAT) in rice seedlings also reached their maximum values simultaneously. Total RNA was extracted for transcriptome sequencing, and differential gene expression analysis was conducted using DESeq2. Transcriptomic sequencing highlighted distinct responses under LSe and HSe conditions. Gene ontology (GO) enrichment analysis revealed significant involvement in processes related to oxidoreductase activity and cellular structures. KEGG pathway analysis emphasized that Se treatments notably enhanced the glutathione metabolism pathway, which is crucial for antioxidant defense. Additionally, significant changes were observed in starch and sucrose metabolism and cysteine (Cys) and methionine (Met) metabolism pathways, showing upregulation under LSe treatment and downregulation under HSe. Six key genes were validated using qRT-PCR, confirming their differential expression under varied Se treatments. The Cys, Met and starch content assays as well as qRT-PCR data demonstrated that LSe promoted the synthesis and accumulation of Cys, Met and starch, supporting enhanced growth and antioxidant capacity. Conversely, HSe inhibited the synthesis and accumulation of Cys, Met and starch in rice seedlings, and these data were also consistent with the physiological phenotype. These findings provide insights into the molecular mechanisms by which rice seedlings adapt to varying Se levels, with implications for Se biofortification and stress management strategies in crops. Full article

As the focus on green chemistry intensifies, researchers are progressively looking to incorporate biodegradable and environmentally friendly solvents. Given the prevalent use of inorganic solvents in conventional methods for detecting selenium content, this study utilized a mixture design approach to create four deep eutectic solvents (DESs). The elements of the DESs consisted of six different compounds: guanidine hydrochloride, fructose, glycerol, citric acid, proline, and choline chloride. The synthesized deep eutectic solvents (DESs) exhibited a uniform and transparent appearance. The ideal ratios for each DES were established based on their density and viscosity measurements, leading to the formulations of DES1 (34% guanidine hydrochloride, 21% fructose, 45% water), DES2 (23% guanidine hydrochloride, 32% glycerol, 45% water), DES3 (27.5% citric acid, 27.5% proline, 45% water), and DES4 (30% choline chloride, 25% citric acid, 45% water). The characterization of the deep eutectic solvents (DESs) was performed using nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy, which confirmed the molecular formation of each DES. Following this, the DESs were applied as extraction solvents in a process involving ultrasonic-assisted microextraction (UAE) combined with inductively coupled plasma mass spectrometry (ICP-MS) to assess the selenium levels in selenium-rich rice. The results were benchmarked against traditional microwave-assisted acid digestion (TM-AD), revealing selenium recovery rates ranging from 85.5% to 106.7%. These results indicate that UAE is an effective method for extracting selenium from selenium-rich rice, thereby establishing a solid data foundation for the environmentally friendly analysis of selenium content in rice. Full article

In this study, 3,4-diaminobenzoic acid (DABA) was introduced into the porphyrin metal–organic framework (PCN-224) for the first time to prepare a ratiometric fluorescent probe (PCN-224-DABA) to quantitatively detect ferric iron (Fe(III)) and selenium (IV) (Se(IV)). The fluorescence attributed to the DABA of PCN-224-DABA at 345 nm can be selectively quenched by Fe(III) and Se(IV), but the fluorescence emission peak attributed to tetrakis (4-carboxyphenyl) porphyrin (TCPP) at 475 nm will not be disturbed. Therefore, the ratio of I_345nm/I_475nm with an excitation wavelength of 270 nm can be designed to determine Fe(III) and Se(IV). After the experimental parameters were systematically optimized, the developed method shows good selectivity and interference resistance for Fe(III) and Se(IV) detection, and has good linearity in the ranges of 0.01–4 μM and 0.01–15 μM for Fe(III) and Se(IV) with a limit of detection of 0.045 μM and 0.804 μM, respectively. Furthermore, the quenching pattern was investigated through the Stern–Volmer equation, and the results suggest that both Se(IV) and Fe(III) quenched on PCN-224-DABA can be attributed to the dynamic quenching. Finally, the constructed ratiometric fluorescent probe was applied in the spiked detection of lake water samples, which shows good applicability in real sample analysis. Moreover, the Fe(III) and Se(IV) contents in spinach and selenium-enriched rice were determined, respectively. Full article

Background: The relationship between consuming Thai desserts—predominantly composed of carbohydrates—and gut microbiome profiles remains unclear. This study aimed to evaluate the effects of consuming various Thai desserts with different GI values on the gut microbiomes of healthy volunteers. Methods: This open-label, parallel randomized clinical trial involved 30 healthy individuals aged 18 to 45 years. Participants were randomly assigned to one of three groups: Phetchaburi’s Custard Cake (192 g, low-GI group, n = 10), Saraburi’s Curry Puff (98 g, medium-GI group, n = 10), and Lampang’s Crispy Rice Cracker (68 g, high-GI group, n = 10), each consumed alongside their standard breakfast. Fecal samples were collected at baseline and 24 h post-intervention for metagenomic analysis of gut microbiome profiles using 16S rRNA gene sequencing. Results: After 24 h, distinct trends in the relative abundance of various gut microbiota were observed among the dessert groups. In the high-GI dessert group, the abundance of Collinsella and Bifidobacterium decreased compared to the low- and medium-GI groups, while Roseburia and Ruminococcus showed slight increases. Correlation analysis revealed a significant negative relationship between sugar intake and Lactobacillus abundance in the medium- and high-GI groups, but not in the low-GI group. Additionally, a moderately negative association was observed between Akkermansia abundance and sugar intake in the high-GI group. These bacteria are implicated in energy metabolism and insulin regulation. LEfSe analysis identified Porphyromonadaceae and Porphyromonas as core microbiota in the low-GI group, whereas Klebsiella was enriched in the high-GI group, with no predominant bacteria identified in the medium-GI group. Conclusions: The findings suggest that Thai desserts with varying GI levels can influence specific gut bacteria, though these effects may be temporary. Full article

Selenium (Se) is an essential trace element that has various beneficial effects for human healthy. However, the effects of different Se forms and concentrations on growth and development, photosynthetic characteristics and antioxidant capacity are still unclear with regard to the dual grain-and-feed dual-use of ratoon rice (RR). In this study, three concentrations of three different Se forms were applied to RR using the foliar spraying method, and the results showed that Se treatment can increase the Se content of rice grain and straw. All the Se treatments improved the photosynthetic indexes and activities of antioxidant enzymes. The Se and trace elements contents, and the percentages of organic Se and protein Se of brown rice were found to be similar in all three Se forms. A higher organic Se content was found in the grain by spraying sodium selenite and Se-Met, in which the resistant starch (RS) content was increased with the increase in amylose content in grains. The main Se species in the grain was SeMet and the SeMeCys was found only with SeMet treatments. The grain quality showed that all three Se forms increased the consistency of gelatinization. Our study indicated that exogenous Se could improve the nutritional quality of both grain and straw by improving photosynthetic traits and antioxidant enzyme activities, especially sodium selenite and Se-Met. These results underscore the potential of foliar biofortification to enhance the functional component contents of RR grains and provide an insight into the Se enrichment of ratoon rice. Full article

Selenium (Se) is crucial for both plants and humans, with plants acting as the main source for human Se intake. In plants, moderate Se enhances growth and increases stress resistance, whereas excessive Se leads to toxicity. The physiological mechanisms by which Se influences rice seedlings’ growth are poorly understood and require additional research. In order to study the effects of selenium stress on rice seedlings, plant phenotype analysis, root scanning, metal ion content determination, physiological response index determination, hormone level determination, quantitative PCR (qPCR), and other methods were used. Our findings indicated that sodium selenite had dual effects on rice seedling growth under hydroponic conditions. At low concentrations, Se treatment promotes rice seedling growth by enhancing biomass, root length, and antioxidant capacity. Conversely, high concentrations of sodium selenite impair and damage rice, as evidenced by leaf yellowing, reduced chlorophyll content, decreased biomass, and stunted growth. Elevated Se levels also significantly affect antioxidase activities and the levels of proline, malondialdehyde, metal ions, and various phytohormones and selenium metabolism, ion transport, and antioxidant genes in rice. The adverse effects of high Se concentrations may directly disrupt protein synthesis or indirectly induce oxidative stress by altering the absorption and synthesis of other compounds. This study aims to elucidate the physiological responses of rice to Se toxicity stress and lay the groundwork for the development of Se-enriched rice varieties. Full article