A fluorometric aptasensor for bisphenol a based on the inner filter effect of gold nanoparticles on the fluorescence of nitrogen-doped carbon dots.

An aptamer-based fluorometric assay is described for the determination of bisphenol A (BPA). The aptamer against BPA is first attached to the surface of the red AuNPs, and this prevents the AuNPs from salt-induced formation of a blue-colored aggregate. Hence, the blue fluorescence of added nitrogen-doped carbon dots (NCDots) is quenched via an inner filter effect (IFE) caused by the red AuNPs. After addition of BPA, the BPA/aptamer complex is formed, and the AuNPs are no longer stabilized agains aggregation. This weakens the IFE and results in the recovery of the fluorescence of the NCDots which is measured best at excitation/emission wavelengths of 300/420 nm. The recovered fluorescence increases linearly in the 10 to 250 nM and 250 to 900 nM BPA concentration ranges, and the detection limit is 3.3 nM. The method was successfully applied to the determination of BPA in spiked environmental tap water samples. Graphical abstract Schematic presentation of a fluorometric aptamer based assay for bisphenol A (BPA). It is based on the inner filter effect of gold nanoparticles (AuNPs) on the fluorescence of nitrogen-doped carbon dots (NCDots).

The Arabidopsis trichome is an active mechanosensory switch.

Trichomes ('hair cells') on Arabidopsis thaliana stem and leaf surfaces provide a range of benefits arising from their shape and disposition. These include tempting herbivores to sample constitutive toxins before they reach the bulk of the tissue. We asked whether, in addition, small mechanical disturbances such as an insect can make elicit signals that might help the plant respond to herbivory. We imaged, pressed and brushed trichomes in several ways, most notably with confocal microscopy of trichomes transgenically provided with apoplastic pH reporter apo-pHusion and cytosolic Ca2+ reporter cameleon. In parallel, we modelled trichome wall mechanics with finite element analysis. The stimulated trichome focuses force on a pliant zone and the adjoining podium of the stalk. A buckling instability can further focus force on a skirt of cells surrounding the podium, eliciting oscillations of cytosolic Ca2+ and shifts in apoplastic pH. These observations represent active physiological response. Modelling establishes that the effectiveness of force focusing and buckling is due to the peculiar tapering wall structure of the trichome. Hypothetically, these active mechanosensing functions enhance toxin synthesis above constitutive levels, probably via a priming process, thus minimizing the costly accumulation of toxins in the absence of herbivore attack but assuring rapid build-up when needed.

Evodiamine Suppresses ABCG2 Mediated Drug Resistance by Inhibiting p50/p65 NF-κB Pathway in Colorectal Cancer.

Evodiamine (Evo), extracted from the Chinese herbal medicine Evodia rutaecarpa, has cytotoxic effects on different types of human cancer cells. However, its effects on drug resistance and their molecular mechanism and therapeutic target in colorectal cancer are not well understood. In the present study, we observed that Evo inhibited cell growth and induced apoptosis in adose-and time-dependent manner in HCT-116/L-OHP cells. Moreover, Evo treatment reduced Rhodamine 123 accumulation and ATPase activity in HCT-116/L-OHP cells, indicating that Evo decreased the efflux function in HCT-116/L-OHP cells. Interestingly, phosphorylation of NF-κB pathway, particularly p50/p65, was also inhibited by Evo treatment. Furthermore the effect of Evo in reversing drug resistance and suppressing phosphorylation of NF-κB pathway were attenuated after treatment with the NF-κB activator (LPS). Additionally, Evo inhibited the tumor growth in a colorectal MDR cancer xenograft model and down regulated p-NF-κB level in vivo. Our study provided the first direct evidence that Evo can attenuate multidrug resistance by blocking p-NF-κB signaling pathway in human colorectal cancer. Evo could be a potential candidate for cancer chemotherapy.

Expression of NUCB2/nesfatin-1 in the taste buds of rats.

Nesfatin-1, an anorexigenic peptide derived from nucleobindin 2 (NUCB2), is closely involved in feeding behavior, glycometabolism, and satiety regulation. Some studies show that NUCB2/nesfatin-1 is highly expressed and interacts with many appetite-regulating peptides that are co-expressed in the gastrointestinal tract. However, it remains unclear whether nesfatin-1 is expressed and interacts similarly in taste buds. Glucagon-like peptide-1 (GLP-1), a well-known appetite down-regulating peptide, is associated with changes in the expression of nesfatin-1. Therefore, we measured the expression of the NUCB2 gene and the distribution of nesfatin-1-immunoreactive cells and investigated whether these variables change in taste buds of circumvallate papillae (CV) from rats with type 2 diabetes (T2DM) after treatment with liraglutide, a GLP-1 receptor agonist. The results showed that nesfatin-1 immunoreactive cells were localized in the taste buds of rat CV. Quantitative RT-PCR showed a significantly lower expression of NUCB2 mRNA in the taste buds of diabetic control rats (T2DM-C) than in those of the normal control group (NC) and a higher level of NUCB2 in the liraglutide treated group (T2DM + LIR) than either the T2DM-C or the NC groups. Changes in the expression of NUCB2 in the rat hypothalamus were opposite to those in CV taste buds. In summary, we found that rat CV taste buds express NUCB2/nesfatin-1, and that this expression decreases significantly in T2DM and increases after treatment with liraglutide in rat CV. This indicates that nesfatin-1 could be an important factor in the regulation of gustatory function, feeding and perhaps energy homeostasis.

Structures formed by a cell membrane-associated arabinogalactan-protein on graphite or mica alone and with Yariv phenylglycosides.

BACKGROUND: Certain membrane-associated arabinogalactan-proteins (AGPs) with lysine-rich sub-domains participate in plant growth, development and resistance to stress. To complement fluorescence imaging of such molecules when tagged and introduced transgenically to the cell periphery and to extend the groundwork for assessing molecular structure, some behaviours of surface-spread AGPs were visualized at the nanometre scale in a simplified electrostatic environment. METHODS: Enhanced green fluorescent protein (EGFP)-labelled LeAGP1 was isolated from Arabidopsis thaliana leaves using antibody-coated magnetic beads, deposited on graphite or mica, and examined with atomic force microscopy (AFM). KEY RESULTS: When deposited at low concentration on graphite, LeAGP can form independent clusters and rings a few nanometres in diameter, often defining deep pits; the aperture of the rings depends on plating parameters. On mica, intermediate and high concentrations, respectively, yielded lacy meshes and solid sheets that could dynamically evolve arcs, rings, 'pores' and 'co-pores', and pits. Glucosyl Yariv reagent combined with the AGP to make very large and distinctive rings. CONCLUSIONS: Diverse cell-specific nano-patterns of native lysine-rich AGPs are expected at the wall-membrane interface and, while there will not be an identical patterning in different environmental settings, AFM imaging suggests protein tendencies for surficial organization and thus opens new avenues for experimentation. Nanopore formation with Yariv reagents suggests how the reagent might bind with AGP to admit Ca(2+) to cells and hints at ways in which AGP might be structured at some cell surfaces.

Zuo Jin Wan reverses P-gp-mediated drug-resistance by inhibiting activation of the PI3K/Akt/NF-κB pathway.

BACKGROUND: Zuo-Jin-Wan (ZJW), a traditional Chinese medicine formula, has been identified to be effective against drug resistance in cancer. In the present study, we investigated the effect of ZJW on acquired oxaliplatin-resistant and the PI3K/Akt/NF-κB pathway in vitro. METHODS: We tested the dose-response relationship of ZJW on reversing drug-resistance by CCK-8 assay and flow cytometry analysis in vitro. The protein expression of P-gp, MRP-2, LRP, and ABCB1 mRNA expression level were evaluated by Western blot and quantitative RT-PCR. The activities of PI3K/Akt/NF-κB pathway were also examined with or without ZJW, including Akt, IκB, p65 and their phosphorylation expression. RESULTS: We found that ZJW significantly enhanced the sensitivity of chemotherapeutic drugs and increased oxaliplatin (L-OHP)-induced cell apoptosis in a time- and dose-dependent manner. Moreover, both ZJW and a PI3K specific inhibitor (LY294002) suppressed phosphorylation of Akt (Ser473) and NF-κB, which is necessary in the activation of the PI3K/Akt/NF-κB pathway. The effect of ZJW in reversing drug-resistance and suppressing phosphorylation of Akt (Ser473) and NF-κB were weakened after treatment with a PI3K/Akt activator in HCT116/L-OHP cells. CONCLUSIONS: Our study has provided the first direct evidence that ZJW reverses drug-resistance in human colorectal cancer by blocking the PI3K/Akt/NF-κB signaling pathway, and could be considered as a useful drug for cancer therapy.

Population dynamics and seasonal migration patterns of Spodoptera exigua in northern China based on 11 years of monitoring data.

Background: The beet armyworm, Spodoptera exigua (Hübner), is an important agricultural pest worldwide that has caused serious economic losses in the main crop-producing areas of China. To effectively monitor and control this pest, it is crucial to investigate its population dynamics and seasonal migration patterns in northern China. Methods: In this study, we monitored the population dynamics of S. exigua using sex pheromone traps in Shenyang, Liaoning Province from 2012 to 2022, combining these data with amigration trajectory simulation approach and synoptic weather analysis. Results: There were significant interannual and seasonal variations in the capture number of S. exigua, and the total number of S. exigua exceeded 2,000 individuals in 2018 and 2020. The highest and lowest numbers of S. exigua were trapped in September and May, accounting for 34.65% ± 6.81% and 0.11% ± 0.04% of the annual totals, respectively. The average occurrence period was 140.9 ± 9.34 days during 2012-2022. In addition, the biomass of S. exigua also increased significantly during these years. The simulated seasonal migration trajectories also revealed varying source regions in different months, primarily originated from Northeast China and East China. These unique insights into the migration patterns of S. exigua will contribute to a deeper understanding of its occurrence in northern China and provide a theoretical basis for regional monitoring, early warning, and the development of effective management strategies for long-range migratory pests.

Recent progress in research on the distribution and function of NUCB2/nesfatin-1 in peripheral tissues.

Nesfatin-1 is a polypeptide derived from the posttranslational processing of the N-terminal fragment of nucleobindin 2 (NUCB2), that was originally identified as an anorexigenic hypothalamic neuropeptide. A number of reports have recently shown that NUCB2/nesfatin-1 is widely expressed in various peripheral tissues, including those of the gastrointestinal tract where it may participate in various pathophysiological processes. One of its roles may be regulation of energy homeostasis. As a result, nesfatin-1 may be a novel target for exploring the underlying mechanisms and the treatment of metabolic syndromes.

Mechanosensation triggers enhanced heavy metal ion uptake by non-glandular trichomes.

The trichomes of Arabidopsis thaliana serve as accumulation sites for heavy metals such as Cd2+, and thereby both help plants cope with heavy metal stress and detoxify the soil. These trichomes are also believed to prime plant defenses against insect herbivores in response to mechanical stimulation. Because Cd2+ in such trichomes may be beneficial for plant defenses, we hypothesized that mechanical stimulation would enhance sequestration of Cd2+ in trichomes. We quantified the distribution and concentration of Cd2+ in leaves of A. thaliana, of the glabrous mutant gl1-1 of A. thaliana, and Brassica rapa L. subsp. pekinensis (Lour.) Hanelt (Chinese cabbage) and examined how these changed following mechanical stimulation of the trichomes or leaves. Light brushing or exposure to caterpillars of Spodoptera exigua led trichomes of both A. thaliana and Chinese cabbage to accumulate Cd2+ complexes more rapidly and to a higher concentration than trichomes in unstimulated controls. Comparison to responses in leaves of gl1-1 mutants suggested that this acceleration and enhancement of Cd2+ storage requires signaling through trichomes. In wild type A. thaliana, Cd2+ was found exclusively in trichomes, whereas in gl1-1 mutants, Cd2+ was found mainly in the - mesophyll cells. Results suggest a mechanobiological pathway for improving heavy metal detoxification of soils through the action of hyperaccumulator plant leaves containing non-glandular trichomes.

[Effect of jianpi jiedu recipe on microvessel density and cyclooxygenase-2 expression in Heliobacter pylori induced gastric cancer].

OBJECTIVE: To investigate the regulatory effect of jianpi jiedu Recipe (JJR) on the microvessel density (MVD) and cyclooxygenase-2 (COX-2) in long-term infection of Helicobacter pylori induced gastric cancer of C57BL/6 mice, thus providing experimental bases for its treatment of the H. pylori correlated gastropathy. METHODS: C57BL/6 mouse gastric cancer model induced by H. pylori infection was established by gastrogavage of H. pylori standard strain SS1. Mice were divided into the control group, the model group, low dose JJR group, and the high dose JJR group, 40 in each group. Mice were sacrificed after 72-week medication. Changes of the gastric mucosa MVD of mice in each group were detected by immunohistochemical method. Expressions of COX-2 mRNA and protein were detected by Real-time fluorescent quantitative polymerase chain reaction and immunohistochemical method. RESULTS: The occurrence rate of gastric cancer in the control group, the model group, the low dose JJR group, and the high dose JJR group was 0, 22.2%, 11.1%, and 10.0%, respectively. The gastric mucosa MVD (number/cm2) of mice in each group was 2.50 +/- 1.54, 18.56 +/- 2.62, 14.61 +/- 3.60, and 7.39 +/- 1.75, respectively. The gastric mucosa MVD in the model group increased more obviously than that in the control group (P < 0.01). The gastric mucosa MVD significantly decreased in the low dose JJR group and the high dose JJR group (P < 0.01). Expressions of COX-2 mRNA and protein in the model group increased more obviously than those in the control group (P < 0.01). Low dose JJR and high dose JJR could decrease their expressions in a dose dependent manner. CONCLUSIONS: H. pylori infection could increase the gastric mucosa MVD of C57BL/6 mice and promote COX-2 expressions, which might play a promoting effect in the incidence of H. pylori induced gastric cancer. JJR could decrease the gastric mucosa MVD and inhibit COX-2 expressions, which might be one of its important mechanisms of preventing and treating gastric cancer.

Mature trichome is the earliest sequestration site of Cd ions in Arabidopsis thaliana leaves.

Sequestration of heavy metals by plants in non-glandular leaf trichomes is important for survival in toxic soils and has the potential for environmental remediation. Although heavy metals are particularly toxic to many plants during development, the integration of sequestration into the developmental timecourse is unknown. We tested the hypothesis that plants preferentially sequester heavy metals into mature trichomes by investigating the timecourse of Cd2+ ions into the leaves of the model plant Arabidopsis thaliana. Results supported the hypothesis and surprisingly showed no Cd2+ ions accumulated in earlier trichome development stages and that sequestration and release by mature trichomes were periodic and dynamic. Studies in mutants suggested that these dynamics were governed by the trichome's secondary cell wall, which matures late in development. Results suggest a developmentally timed pathway for excluding heavy metal toxins and the existence of mechanisms for controlled release that may relate to proposed functions of mature trichomes in plants.

An effective solution to simultaneously analyze size, mass and number concentration of polydisperse nanoplastics in a biological matrix: asymmetrical flow field fractionation coupled with a diode array detector and multiangle light scattering.

To accurately understand the biological pollution level and toxicity of polydisperse nanoplastics, an effective solution is presented to separate polydisperse nanoplastics and detect their size, mass and number concentration in a biological matrix by asymmetrical flow field fractionation coupled with a diode array detector and a multiangle light scattering detector.

Effects of mild moxibustion on intestinal microbiome and NLRP3 inflammasome in rats with 5-fluorouracil-induced intestinal mucositis.

OBJECTIVE: The present study investigated how mild moxibustion treatment affects the intestinal microbiome and expression of NLRP3-related immune factors in a rat model of intestinal mucositis (IM) induced with 5-fluorouracil (5-Fu). METHODS: Forty male Sprague-Dawley rats were randomly divided into control, chemotherapy, moxibustion and probiotics groups. The IM rat model was established by intraperitoneal injection of 5-Fu. Mild moxibustion treatment and intragastric probiotic administration were provided once daily for 15 days. Tissue morphology, serum levels of inflammatory factors and the expression levels of tight junction proteins, caspase-1, gasdermin D and NLRP3 were evaluated in colon tissue, through hematoxylin and eosin staining, electron microscopy, enzyme-linked immunosorbent assay, Western blotting, quantitative real-time reverse transcription polymerase chain reaction and immunofluorescence. Gut microbiome profiling was conducted through 16S rRNA amplicon sequencing. RESULTS: Moxibustion and probiotic treatments significantly increased the expression levels of tight junction proteins, reduced cell apoptosis and the expression levels of caspase-1, gasdermin D and NLRP3; they also decreased the serum levels of tumor necrosis factor-α, interleukin (IL)-6, IL-1ß and IL-18, while increasing serum levels of IL-10. Moxibustion and probiotic treatments also corrected the reduction in α-diversity and ß-diversity in IM rats, greatly increased the proportion of the dominant bacterial genus Lactobacillus and reduced the abundance of the genera Roseburia and Escherichia in chemotherapy-treated rats to levels observed in healthy animals. We also found that these dominant genera were firmly correlated with the regulation of pyroptosis-associated proteins and inflammatory factors. Finally, moxibustion and probiotic treatments elicited similar effects in regulating intestinal host-microbial homeostasis and the expression of NLRP3 inflammasome-related factors. CONCLUSION: Moxibustion exerts its therapeutic effect on IM by ameliorating mucosal damage and reducing inflammation. Moreover, moxibustion modulates the gut microbiota, likely via decreasing the expression levels of the NLRP3 inflammasome.

[Chinese herbal medicine Jianpi Jiedu Formula down-regulates the expression of vascular endothelial growth factor in human gastric cell line MKN45 induced by Helicobacter pylori by inhibiting cyclooxygenase-2].

OBJECTIVE: To investigate the effects of Jianpi Jiedu Formula (JPJDF), a compound Chinese herbal medicine, on vascular endothelial growth factor (VEGF) expression induced by Helicobacter pylori (Hp) in human gastric cancer cells, and to explore the possible mechanism. METHODS: Human gastric MKN45 cancer cells were infected with standard Hp NCTC11637 by coculture, and the cells were divided into 7 groups: normal control group, Hp group, NS398 inhibitor group, blank serum group, and 5%, 10% and 20% JPJDF groups. The expressions of VEGF and cyclooxygenase-2 (COX-2) mRNAs in human gastric cancer cells infected by Hp were evaluated by real-time fluorogenic quantitative polymerase chain reaction (PCR). After inhibiting the expression of COX-2 with COX-2 specific inhibitor NS398 (50 µmol/L), VEGF mRNA expression induced by Hp in human gastric cancer MKN45 cells was evaluated by real-time fluorogenic quantitative PCR. RESULTS: Real-time fluorogenic quantitative PCR results showed that COX-2 mRNA expression increased significantly after MKN45 cells were infected with Hp for 6 h (P<0.01), and VEGF mRNA expression also increased significantly after MKN45 cells were infected with Hp for 12 h as compared with the normal control group (P<0.01). After inhibiting COX-2 expression with COX-2 specific inhibitor NS398, Hp-induced VEGF mRNA expression significantly reduced (P<0.01). 5%, 10% and 20% JPJDF-containing sera all down-regulated VEGF and COX-2 mRNA expressions induced by Hp in a dose-dependent manner as compared with the Hp infection group. CONCLUSION: Hp could induce the expressions of COX-2 and VEGF in human gastric cancer cells, and JPJDF down-regulates Hp-induced expression of VEGF by inhibiting COX-2, which might be one of the important mechanisms of its prevention and treatment of gastric cancer.

Reactivity of gamma-hydroxy-alpha,beta-acetylenic esters with amines: facile synthesis of the optically active 4-amino-2(5H)-furanones.

A convenient synthesis of the optically active 4-amino-2(5H)-furanones is discovered by combining an asymmetric alkyne addition to aldehydes and a subsequent aliphatic amine addition. Both steps can be conducted at room temperature and the products are obtained with high enantioselectivity (84-90% ee). The 4-amino-2(5H)-furanones are also found to undergo very facile electrophilic substitution reactions.

Synthesis of a novel linear polymer of a macrocyclic polyamine copper (II) complex and its interaction with plasmid DNA.

The novel linear polymer of a macrocyclic polyamine copper (II) complex, which has many cyclen groups linked by epichlorohydrin, has been synthesized as a DNA cleavage agent. The structure of the polymer 3 was identified by 1HNMR and IR and its molecular weight was measured by GPC. The result of agarose gel electrophoresis assay showed that Cu-(II) complex 4 could act as a powerful catalyst for the cleavage of plasmid DNA under physiological conditions.

A new Schiff base copper (II) complex derived from estrone and d-glucosamine: Synthesis, characterization and its interaction with DNA.

A novel copper (II) complex of Schiff base prepared through condensation between 2-formyl-17-deoxyestrone and d-glucosamine was synthesized and characterized. Fluorescence spectroscopy was conducted to assess their binding ability with CT-DNA. The results showed that the copper (II) complex could bind to DNA with a weak intercalative mode. The interaction between the copper (II) complex and DNA was also investigated by gel electrophoresis. Interestingly, we found that the complex could cleave plasmid DNA (pUC19) to nicked and linear forms through an oxidative mechanism without the use of exogenous agents.

Cyclen-based side-chain homopolymer self-assembly with plasmid DNA: protection of DNA from enzymatic degradation.

In this study, a 1,4,7,10-tetraazacyclododecane (cyclen)-based side-chain homopolymer was developed for the first time; this polymer can self-assembly with plasmid DNA to form polyelectrolyte complexes (polyplex), which can protect DNA from enzymatic degradation. Moreover, the polyplex can disassembly and release free DNA when NaCl solution is added to this system. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used for imaging of the surface structure of the polyplex, and results indicated that the polyplex structures respond to the polymer concentration. Circular dichroism (CD) spectrum suggested that the DNA configuration in the polyplex was retained.

Synthesis, DNA binding and cleavage activities of the copper (II) complexes of estrogen-macrocyclic polyamine conjugates.

A series of the copper (II) complexes 5a-d of estrogen-macrocyclic polyamine conjugates were synthesized and characterized. The interactions of complexes 5a-d with DNA were studied by fluorescence spectroscopy and gel electrophoresis under physiological conditions. The results indicate that the conjugated estrogens have increased the cleavage efficiency of Cu[cyclen](2+) while the conjugates display poor binding affinities. The functional groups of D-ring of estrogens may play a key role in deciding binding and cleavage extent of the complexes to DNA.

Expression of glucagon-like peptide-1 in the taste buds of rat circumvallate papillae.

Glucagon-like peptide-1 (GLP-1), a 30-amino-acid peptide hormone, is a typical peptide of the brain-gut axis and can affect the metabolism of various tissues and organs. GLP-1 is secreted by intestinal L cells in response to nutrient ingestion. Some studies have shown that taste signaling elements were co-expressed in enteroendocrine cells of the small intestine, and in particular by L-cells. The present study was performed to explore the protein and mRNA expression of GLP-1 in the taste buds of rat circumvallate papillae and to try to determine the significance of its secretion. GLP-1 immunoreactivity was observed in spindle-shaped taste bud cells, with positive cells displaying a characteristic distribution of reaction product that was confined to the cytosol. Reverse transcription polymerase chain reaction (RT-PCR) assay showed that GLP-1 mRNA was expressed in circumvallate papillae. The expression of GLP-1 suggests that it may play an important role in the taste stimulation of nutrients and gut hormone secretion.