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BACKGROUND: In response to growing concerns regarding heavy metal contamination in food, particularly chromium (Cr)(VI) contamination, this study presented a simple, sensitive and practical method for Cr(VI) detection. RESULTS: A magnetic separation‐based capture–exponential enrichment ligand system evolution (SELEX) method was used to identify and characterize DNA aptamers with a high affinity for Cr(VI). An aptamer, Cr‐15, with a dissociation constant (Kd) of 4.42 ± 0.44 μmol L−1 was obtained after only eight rounds of selection. Further innovative methods combining molecular docking, dynamic simulation and thermodynamic analysis revealed that CrO42− could bind to the 19th and 20th guanine bases of Cr‐15 via hydrogen bonds. Crucially, a label‐free fluorometric aptasensor based on SYBR Green I was successfully constructed to detect CrO42−, achieving a linear detection range of 60–300 nmol L−1 with a lower limit of detection of 44.31 nmol L−1. Additionally, this aptasensor was able to quantitatively detect CrO42− in grapes and broccoli within 40 min, with spike recovery rates ranging from 89.22% to 108.05%. The designed fluorometric aptasensor exhibited high selectivity and could detect CrO42− in real samples without sample processing or target pre‐enrichment. CONCLUSION: The aptasensor demonstrated its potential as a reliable tool for monitoring Cr(VI) contamination in fruit and vegetable products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Microorganisms in the plant's rhizosphere are capable of solubilising insoluble soil phosphates and can promote plant growth. In this study, a total of 30 bacteria were isolated from soils in Changji city, and one highly efficient strain (B5) was identified as a member of Pseudomonadaceae. B5 exhibited phosphorus (P) solubilisation of 519.66 mg/L in a culture medium containing tricalcium phosphate (Ca3 (PO4)2). Results showed that strain B5 had a high P utilisation rate in a medium containing glucose (monosaccharide), ammonium sulphate and tricalcium phosphate. B5 treatment significantly promoted plant growth and increased the dry weight, the chlorophyll content as well as P content of tomato, marigold and cucumber. Moreover, B5 produced plant growth-promoting hormones, including indole-3-acetic acid (IAA) (4.18 g/L) and gibberellin (GA) (19.8 mg/L). In addition, organic acids including oxalic acid, succinic acid, gluconic acid, arabic-hexanoic acid and glutraic acid were produced by B5 under different phosphorus sources. Our results indicated that B5 is a potential candidate for development as a bioinoculant for horticultural application. [ABSTRACT FROM AUTHOR]

The countries taking part in China's 'The Belt and Road' Initiative have achieved greatly increased trade volume and become more firmly interconnected since the initiative was launched in September 2013. This paper researches the exchange rate volatility features among 15 countries along the Belt and Road region with the network analysis based on spillover effect. A directed network is constructed to show not only the impact one currency having on and received from the other currencies, but also the net effect from one currency to another in the network. The importance of any currency in the network and the total interconnectedness of the whole network can also be obtained. Furthermore, a 200-day rolling window analysis is used to show the dynamic evolution trend of the network. The results show that after the launch of the Belt and Road Initiative, both the interconnectedness of the exchange rate volatility network and the importance of CNY increase. In addition, the importance of most currencies in the network has been quite volatile. [ABSTRACT FROM AUTHOR]

BACKGROUND Insect tolerance to low oxygen (hypoxia) and high carbon dioxide (hypercapnia) is critical for insect control. On the basis of bioassay, metabolism profiles were built to investigate adaptive mechanisms in bean weevil under hypoxia (2% O2), hypoxia/hypercapnia (2% O2 + 18% CO2) and normoxia (control, 20% O2 + 80% N2) using gas chromatography/time-of-flight mass spectrometry ( GC/ TOF-MS). RESULTS The growth and development of bean weevils were significantly suppressed by the two hypoxia conditions; hypercapnia enhanced the mortality, but after 24 days of exposure, the surviving insects emerged as adults earlier than those under hypoxia only. Metabolism profiles also showed striking differences in metabolites among the treatment and control groups, both quantitatively and qualitatively. Pairwise comparisons of the three groups showed that 61 metabolites changed significantly, 40 in the hypoxia group and 37 in the hypoxia/hypercapnia group relative to the control group, while only 16 were shared equally by the hypoxia and hypoxia/hypercapnia groups. Increased metabolites were mainly carbohydrates, amino acids and organic acids, while free fatty acids were decreased. Furthermore, the changes were strengthened by the addition of hypercapnia, but excluding free fatty acids. CONCLUSION The findings show that bean weevil has high tolerance to hypoxia or even hypoxia/hypercapnia at biologically achievable levels and provide more direct evidence for stored product insect mechanism regulation under hypoxia stress, especially free fatty acid regulation by hypercapnia but not by hypoxia. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract Methyl benzoate (MB) is a common component of floral scents released by many plants. Recent research showed that MB was an alternative insecticide to control insect pests. However, the molecular mechanisms of insect pests in responses to MB are largely unknown, which limits the future applications of this promising insecticidal candidate. In this study, the total transcriptomic analysis for red flour beetle larvae after MB fumigation was performed. Of the 430 identified differentially expressed genes, 197 were upregulated and 233 were downregulated. GO and KEGG pathway enrichment were used to interpret gene classification/function and metabolic/signaling pathways, respectively. And we performed RT-qPCR to validate expressional profiles of identified DEGs. Genes that are involved in energy metabolism, xenobiotic metabolism, and digestive enzymes were shown to be differentially expressed, suggesting that MB have an impact on these physiological processes. This research will enrich our knowledge about the mechanisms of MB-fumigation response genes for stored-product pests. A better understanding of molecular response to MB will facilitate future applications to control stored-product pests. [ABSTRACT FROM AUTHOR]

The phytotoxin coronatine (COR) promotes various aspects of Pseudomonas syringae virulence, including invasion through stomata, growth in the apoplast, and induction of disease symptoms. COR is a structural mimic of active jasmonic acid (JA) conjugates. Known activities of COR are mediated through its binding to the F-box–containing JA coreceptor CORONATINE INSENSITIVE1. By analyzing the interaction of P. syringae mutants with Arabidopsis thaliana mutants, we demonstrate that, in the apoplastic space of Arabidopsis , COR is a multifunctional defense suppressor. COR and the critical P. syringae type III effector HopM1 target distinct signaling steps to suppress callose deposition. In addition to its well-documented ability to suppress salicylic acid (SA) signaling, COR suppresses an SA -independent pathway contributing to callose deposition by reducing accumulation of an indole glucosinolate upstream of the activity of the PEN2 myrosinase. COR also suppresses callose deposition and promotes bacterial growth in coi1 mutant plants, indicating that COR may have multiple targets inside plant cells. [ABSTRACT FROM AUTHOR]

The destructive bacterial wilt disease caused by Ralstonia solanacearum leads to substantial losses in tomato production worldwide. RNA‐seq is a powerful technology to decipher various biological processes of host–pathogen interactions by analysing differentially expressed genes (DEGs). In the current study, we used RNA‐seq to analyse the transcriptome changes during the interaction of R. solanacearum and susceptible tomato leaves at the time point of 24 h. Gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were used to annotate functions of DEGs in tomato plants. DEGs related to plant and pathogen interaction pathways, photosynthesis pathways and hormone signalling pathways were further analysed. Our results revealed that R. solanacearum inoculation activated plant defence response pathways to induce a number of core defence genes against bacterial invasion, inhibited expression of genes related to photosynthesis processes and activated the salicylic acid (SA) signalling pathway to induce defence responses. We quantified SA and jasmonic acid (JA) contents after bacterial inoculation. SA treatment alleviated plant disease symptoms and induced immune‐related reactive oxygen species (ROS) bursts in tomato leaves. The extent of disease symptoms was much greater in SlNPR1‐silenced plants than wild‐type plants. Together, our results will provide a better understanding of the mechanisms of plant induced defences against bacterial invasion and provide a theoretical basis for breeding resistance of tomato against R. solanacearum in future. [ABSTRACT FROM AUTHOR]

Construction of transgenic plants is central to modern plant molecular genetics. Inducible systems permit spatial and temporal control of transgene expression. One commonly used inducible system relies on the use of dexamethasone to activate an endogenously expressed hybrid transcription factor, which positively regulates the expression of the gene of interest (Aoyama and Chua, Plant J 11:605-612, 1997). We have developed Arabidopsis plants using this inducible system to drive expression of a bacterial type III effector protein. The effector, AvrRpm1, elicits either strong cell death or weak cell death and chlorosis depending on the genetic background of the plant. Using these reagents, we examine several properties of the inducible system in Arabidopsis, including the timing of induction, the ability to tune the level of transgene expression by altering the concentration of applied dexamethasone, and the movement of dexamethasone within the plant.