Assessing the quality and eco-beneficial microbes in the use of silkworm excrement compost.

Sericulture has become widespread globally, and the utilization of artificial diets produces a substantial quantity of silkworm excrement. Although silkworm excrement can be composted for environmentally friendly disposal, the potential utility of the resulting compost remains underexplored. The aim of this study was to assess the quality of this unique compost and screen for eco-beneficial microbes, providing a new perspective on microbial research in waste management, especially in sustainable agriculture. The low-concentration compost application exhibited a greater plant growth-promoting effect, which was attributed to an appropriate nutritional value (N, P, K, and dissolved organic matter) and the presence of plant growth-promoting bacteria (PGPB) within the compost. Encouraged by the "One Health" concept, the eco-benefits of potent PGPB, namely, Klebsiella pneumoniae and Bacillus licheniformis, in sericulture were further evaluated. For plants, K. pneumoniae and B. licheniformis increased plant weight by 152.44 % and 130.91 %, respectively. We also found that even a simple synthetic community composed of the two bacteria performed better than any single bacterium. For animals, K. pneumoniae significantly increased the silkworm (Qiufeng × Baiyu strain) cocoon shell weight by 111.94 %, which could increase sericulture profitability. We also elucidated the mechanism by which K. pneumoniae assisted silkworms in degrading tannic acid, a common plant-derived antifeedant, thereby increasing silkworm feed efficiency. Overall, these findings provide the first data revealing multiple beneficial interactions among silkworm excrement-derived microbes, plants, and animals, highlighting the importance of focusing on microbes in sustainable agriculture.

Multiomics analysis reveals the molecular basis for increased body weight in silkworms (Bombyx mori) exposed to environmental concentrations of polystyrene micro- and nanoplastics.

INTRODUCTION: Micro- and nanoplastics (MNPs) are emerging environmental pollutants that have raised serious concerns about their potential impact on ecosystem and organism health. Despite increasing efforts to investigate the impacts of micro- and nanoplastics (MNPs) on biota little is known about their potential impacts on terrestrial organisms, especially insects, at environmental concentrations. OBJECTIVES: To address this gap, we used an insect model, silkworm Bombyx mori to examine the potential long-term impacts of different sizes of polystyrene (PS) MNPs at environmentally realistic concentrations (0.25 to 1.0 µg/mL). METHODS: After exposure to PS-MNPs over most of the larval lifetime (from second to last instar), the endpoints were examined by an integrated physiological (growth and survival) and multiomics approach (metabolomics, 16S rRNA, and transcriptomics). RESULTS: Our results indicated that dietary exposures to PS-MNPs had no lethal effect on survivorship, but interestingly, increased host body weight. Multiomics analysis revealed that PS-MNPs exposure significantly altered multiple pathways, particularly lipid metabolism, leading to enriched energy reserves. Furthermore, the exposure changed the structure and composition of the gut microbiome and increased the abundance of gut bacteria Acinetobacter and Enterococcus. Notably, the predicted functional profiles and metabolite expressions were significantly correlated with bacterial abundance. Importantly, these observed effects were particle size-dependent and were ranked as PS-S (91.92 nm) > PS-M (5.69 µm) > PS-L (9.7 µm). CONCLUSION: Overall, PS-MNPs at environmentally realistic concentrations exerted stimulatory effects on energy metabolism that subsequently enhanced body weight in silkworms, suggesting that chronic PS-MNPs exposure might trigger weight gain in animals and humans by influencing host energy and microbiota homeostasis.

Case Report: A case of hepatocellular carcinoma with aberrant right hepatic artery treated with transarterial chemoembolization and infusion chemotherapy separately to bilobar lesion combining with systemic therapies and sequential hepatectomy.

Background: Hepatocellular carcinoma (HCC) with a dismal prognosis is the second most deadly malignancy globally. Surgery is believed to be a curative approach. Nevertheless, there is still a considerable probability of postoperative recurrence. Most patients present in advanced stages with a surgically and oncologically unresectable disease. Systemic medicines are increasingly important to downstage the disease and further improve survival. Case summary: A 67-year-old Chinese man with uncontrolled hepatitis B was discovered to have liver masses with abnormal serum vitamin K absence or antagonist-II (PIVKA-II) level during checkup for upper abdominal discomfort. Abdominal multiphase computerized tomography (CT) and gadoxetate disodium-enhanced magnetic resonance imaging (MRI) showed the bulky bilobar HCCs of Barcelona Clinic Liver Cancer stage B and China Liver Cancer Staging stage IIa. Furthermore, the aberrant right hepatic artery (RHA) originates from the superior mesenteric artery. Due to the location being adjacent to important vasculatures and massive size of the right-sided lesion, curative resection appears to be challenging. To achieve a favorable surgical margin, repeated hepatic arterial infusion chemotherapy (HAIC) was adopted through the variant RHA, while transarterial chemoembolization (TACE) was delivered to the left lobe to arrest tumor growth. Furthermore, sintilimab plus lenvatinib served as the sequential systemic therapy. After 5 months of conversion treatment, the partial response with a decreased serum PIVKA-II level was attained. The R0 hepatectomy was then performed without postoperative complications. The immunohistochemistry and next-generation sequencing results suggested that the two-side HCCs existing tumor heterogeneity were not completely consistent. The patient continues to be without evidence of disease. Conclusion: Our case highlights a favorable outcome in a man with bilobar bulky HCC after undergoing the comprehensive therapeutic schedule that includes personalized intervention and systemic drug therapy. In terms of conversion therapy, our case provides a secure and practical reference for managing unresectable bilobar HCC coexisting with the aberrant hepatic artery.

Primer selection impacts the evaluation of microecological patterns in environmental microbiomes.

This study revealed that primer selection substantially influences the taxonomic and predicted functional composition and the characterization of microecological patterns, which was not alleviated by close-reference clustering. Biases were relatively consistent across different habitats in community profiling but not in microecological patterns. These primer biases could be attributed to multiple aspects, including taxa specificity, regional hypervariability, and amplification efficiency.

Smartphones as an Ecological Niche of Microorganisms: Microbial Activities, Assembly, and Opportunistic Pathogens.

Smartphone usage and contact frequency are unprecedentedly high in this era, and they affect humans mentally and physically. However, the characteristics of the microorganisms associated with smartphones and smartphone hygiene habits remain unclear. In this study, using various culture-independent techniques, including high-throughput sequencing, real-time quantitative PCR (RT-qPCR), the ATP bioluminescence system, and electron microscopy, we investigated the structure, assembly, quantity, and dynamic metabolic activity of the bacterial community on smartphone surfaces and the user's dominant and nondominant hands. We found that smartphone microbiotas are more similar to the nondominant hand microbiotas than the dominant hand microbiotas and show significantly decreased phylogenetic diversity and stronger deterministic processes than the hand microbiota. Significant interindividual microbiota differences were observed, contributing to an average owner identification accuracy of 70.6% using smartphone microbiota. Furthermore, it is estimated that approximately 1.75 × 106 bacteria (2.24 × 104/cm2) exist on the touchscreen of a single smartphone, and microbial activities remain stable for at least 48 h. Scanning electron microscopy detected large fragments harboring microorganisms, suggesting that smartphone microbiotas live on the secreta or other substances, e.g., human cell debris and food debris. Fortunately, simple smartphone cleaning/hygiene could significantly reduce the bacterial load. Taken together, our results demonstrate that smartphone surfaces not only are a reservoir of microbes but also provide an ecological niche in which microbiotas, particularly opportunistic pathogens, can survive, be active, and even grow. IMPORTANCE Currently, people spend an average of 4.2 h per day on their smartphones. Due to the COVID-19 pandemic, this figure may still be increasing. The high frequency of smartphone usage may allow microbes, particularly pathogens, to attach to-and even survive on-phone surfaces, potentially causing adverse effects on humans. We employed various culture-independent techniques in this study to evaluate the microbiological features and hygiene of smartphones, including community assembly, bacterial load, and activity. Our data showed that deterministic processes drive smartphone microbiota assembly and that approximately 1.75 × 106 bacteria exist on a single smartphone touchscreen, with activities being stable for at least 48 h. Fortunately, simple smartphone cleaning/hygiene could significantly reduce the bacterial load. This work expands our understanding of the microbial ecology of smartphone surfaces and might facilitate the development of electronic device cleaning/hygiene guidelines to support public health.

Deciphering environmental resistome and mobilome risks on the stone monument: A reservoir of antimicrobial resistance genes.

Antimicrobial resistance (AMR) in the environment has attracted increasing attention as an emerging global threat to public health. Stone is an essential ecosystem in nature and also an important material for human society, having architectural and aesthetic values. However, little is known about the AMR in stone ecosystems, particularly in the stone monument, where antimicrobials are often applied against biodeterioration. Here, we provide the first detailed metagenomic study of AMR genes across different types of biodeteriorated stone monuments, which revealed abundant and diverse AMR genes conferring resistance to drugs (antibiotics), biocides, and metals. Totally, 132 AMR subtypes belonging to 27 AMR types were detected including copper-, rifampin-, and aminocoumarins-resistance genes, of which diversity was mainly explained by the spatial turnover (replacement of genes between samples) rather than nestedness (loss of nested genes between samples). Source track analysis confirms that stone resistomes are likely driven by anthropogenic activities across stone heritage areas. We also detected various mobile genetic elements (namely mobilome, e.g., prophages, plasmids, and insertion sequences) that could accelerate replication and horizontal transfer of AMR genes. Host-tracking analysis further identified multiple biodeterioration-related bacterial genera such as Pseudonocardia, Sphingmonas, and Streptomyces as the major hosts of resistome. Taken together, these findings highlight that stone microbiota is one of the natural reservoirs of antimicrobial-resistant hazards, and the diverse resistome and mobilome carried by active biodeteriogens may improve their adaptation on stone and even deactivate the antimicrobials applied against biodeterioration. This enhanced knowledge may also provide novel and specific avenues for environmental management and stone heritage protection.

From surviving to thriving, the assembly processes of microbial communities in stone biodeterioration: A case study of the West Lake UNESCO World Heritage area in China.

Serious concerns regarding stone biodeterioration have been raised due to the loss of aesthetic value and hidden dangers in stone cultural heritages and buildings. Stone biodeterioration involves a complex ecological interplay among organisms, however, the ecological mechanisms (deterministic or stochastic processes) that determine the microbial community on stone remain poorly understood. Here, using both amplicon and shotgun metagenomic sequencing approaches, we comprehensively investigated the biodiversity, assembly, and function of communities (including prokaryotes, fungi, microfauna, and plants) on various types of deteriorating limestone across different habitats in Feilaifeng. By generalizing classic ecological models to stone habitats, we further uncovered and quantified the mechanisms underlying microbial community assembly processes and microbial interactions within the biodeteriorated limestone. Community profiling revealed stable ecosystem functional potential despite high taxonomic variation across different biodeterioration types, suggesting non-random community assembly. Increased niche differentiation occurred in prokaryotes and fungi but not in microfauna and plant during biodeterioration. Certain microbial groups such as nitrifying archaea and bacteria showed wider niche breadth and likely contributing to the initiation, succession and expansion of stone biodeterioration. Consistently, prokaryotes were more strongly structured by selection-based deterministic processes, while micro-eukaryotes were more influenced by dispersal and drift-based stochastic processes. Importantly, microbial coexistence maintains network robustness within stone microbiotas, highlighting mutual cooperation among functional microorganisms. These results provide new insights into microbial community assembly mechanisms in stone ecosystems and may aid in the sustainable conservation of stone materials of interest.

Contribution of sample processing to gut microbiome analysis in the model Lepidoptera, silkworm Bombyx mori.

Microbes that live inside insects play various roles in host biology, ranging from nutrient supplementation to host defense. Although Lepidoptera (butterflies and moths) are one of the most diverse insect taxa and important in natural ecosystems, their microbiotas are little-studied, and to understand their structure and function, it is necessary to identify potential factors that affect microbiome analysis. Using a model organism, the silkworm Bombyx mori, we investigated the effects of different sample types (whole gut, gut content, gut tissue, starvation, or frass) and metagenomic DNA extraction methodologies (small-scale versus large-scale) on the composition and diversity of the caterpillar gut microbial communities. High-throughput 16S rRNA gene sequencing and computational analysis of the resulting data unraveled that DNA extraction has a large effect on the outcome of metagenomic analysis: significant biases were observed in estimates of community diversity and in the ratio between Gram-positive and Gram-negative bacteria. Furthermore, bacterial communities differed significantly among sample types. The gut content and whole gut samples differed least, both had a higher percentage of Enterococcus and Acinetobacter species; whereas the frass and starvation samples differed substantially from the whole gut and were poor representatives of the gut microbiome. Thus, we recommend a small-scale DNA extraction methodology for sampling the whole gut under normal insect rearing conditions whenever possible, as this approach provides the most accurate assessment of the gut microbiome. Our study highlights that evaluation of the optimal sample-processing approach should be the first step taken to confidently assess the contributions of microbiota to Lepidoptera.

The High Expression of PTPRH Is Associated with Poor Prognosis of Human Lung Adenocarcinoma.

OBJECTIVE: The aim of the study is to explore the prognosis value of PTPRH in patients with lung adenocarcinoma (LUAD). METHODS: Oncomine, UALCAN, and GEPIA databases were employed to examine the differential expression of PTPRH between LUAD and adjacent tissues. 100 pairs of LUAD and adjacent tissue samples were involved in this study. qRT-PCR and immunohistochemical staining were performed. Meanwhile, we analyzed The Cancer Genome Atlas (TCGA) data to investigate the correlation between PTPRH gene expression and clinicopathological characteristics. Kaplan-Meier analysis and univariate and multivariate Cox analyses were performed to estimate the relationship between PTPRH expression and LUAD prognosis. The evaluation performance was verified by drawing a ROC curve. In addition, through GSEA, the changes of PTPRH expression were analyzed by GSEA to screen out primarily affected signaling pathway. RESULTS: Oncomine, UALCAN, and GEPIA databases showed that the mRNA expression of PTPRH in LUAD tissues was significantly higher than that in adjacent tissues. qRT-PCR and immunohistochemical staining indicated the mRNA and protein levels of PTPRH in LUAD tissues were markedly upregulated. TCGA data showed that the expression of PTPRH was significantly correlated with T stage and disease stage. Kaplan-Meier analysis showed that the patients with high PTPRH expression had a poor prognosis. Univariate and multivariate Cox analyses exhibited that PTPRH expression could act as an independent prognostic factor for LUAD. The ROC curve showed that PTPRH combined with various clinicopathological features could effectively predict the prognosis of LUAD. Finally, GSEA indicated that changes in PTPRH expression level may affect p53, VEGF, Notch, and mTOR cancer-related signaling pathways. CONCLUSION: Our results demonstrated that PTPRH was highly expressed in LUAD and may be closely correlated with the poor prognosis of LUAD patients.

Toxic effects of acute exposure to polystyrene microplastics and nanoplastics on the model insect, silkworm Bombyx mori.

Microplastics and nanoplastics (MPs and NPs, respectively) are major contaminants of environmental concern due to their potentially detrimental effects on aquatic and terrestrial ecosystems. However, little is known about their potential toxicity in terrestrial organisms. Here, we used the model insect silkworm (Bombyx mori) to evaluate the potential hazardous effects of acute exposure (72 h) to polystyrene (PS) MPs and NPs at physiological, molecular, and biochemical levels as well as their impact on pathogen infection. Our results revealed no significant changes in larval body mass or survival. Nevertheless, exposure led to significant alterations in the expression of immunity-related genes (Cecropin A, Lysozyme, SOD, and GST) and antioxidant-mediated protective response (SOD, GST, and CAT enzymes) which differed in the PS-MP and PS-NP groups. Interestingly, PS-MPs induced a stronger immune response (higher expressions of Lysozyme, SOD, and GST genes along with increased activities of SOD, GST, and CAT enzymes) while the PS-NP response was more that of an inhibitory nature (decreased SOD activity and expression). As a result, upon infection with the natural pathogen Serratia marcescens Bm1, the PS-MP-exposed individuals survived the infection better whereas, PS-NP-exposed individuals exhibited significantly higher mortality. Thus, we infer that PS-MPs/NPs present ecological toxicity, which is closely related to their size, and that their exposure may render the organisms vulnerable or confer resistance to pathogen infections and ecotoxicants. Given the suitability of silkworm as a model organism, this study may promote its application for further investigation of the mechanism of adverse outcome pathways and in studies on bio-nano interactions.

Utilization of Elemental Sulfur in Constructed Wetlands Amended with Granular Activated Carbon for High-Rate Nitrogen Removal.

To investigate the role of granular activated carbon (GAC) on nitrogen removal performance of elemental sulfur-based constructed wetlands (S0-based CWs), three systems were constructed according to the different configurations in the functional layer, namely S-CW (S0 added in the functional layer), CSC-CW (GAC, S0 and GAC placed in layers in the functional layer) and SC-CW (S0 and GAC mixed evenly in the functional layer). In CSC-CW and SC-CW, the volumetric ratio of S0:GAC was 9:1. Three CWs were operated under four different hydraulic retention times (HRTs) ranged from 48 h to 6 h. Over the experiment, total inorganic nitrogen (TIN) removal rates of the three CWs were 3.1 - 23.6 g m-2 d-1, 3.5 - 24.1 g m-2 d-1 and 3.4 - 11.5 g m-2 d-1, respectively; CSC-CW remained high TIN removal efficiency (from 74.7 ± 20.2 % to 93.4 ± 1.9 %) while SC-CW had significant lower values when HRT = 6 h (29.8 ± 30.1 %). Mass balance and high-throughput sequencing analysis revealed that mixotrophic denitrification at the sulfur layer and simultaneous nitrification-denitrification (SND) at the rhizosphere played the major role in N removal from CSC-CW (> 95 %). GAC addition facilitated the growth of Iris pseudacorus with the final fresh weight increased from 33.9 gFW ind-1 to 82.3 gFW ind-1 in CSC-CW and 82.7 gFW ind-1 in SC-CW. This study optimizes the practical application of S0-based CWs amended with GAC for N removal from carbon-limited wastewater.

Treatment for lumbar spinal stenosis secondary to ligamentum flavum hypertrophy using percutaneous endoscopy through interlaminar approach: a retrospective study.

BACKGROUND: This paper is to describe percutaneous endoscopy in the treatment of lumbar spinal stenosis secondary to ligamentum flavum hypertrophy targeted and to investigate the efficacy and safety of percutaneous endoscopy in the treatment of this kind of lumbar spinal stenosis in elderly patients. METHOD: A retrospective analysis of 40 elderly patients with lumbar spinal stenosis secondary to ligamentum flavum hypertrophy admitted between January 2016 and January 2018 was performed. According to different surgical methods, they were divided into two groups: the control group and the endoscopy group (interlaminar approach), 20 people per group. There were 9 males and 11 females in the control group; the age of patients was 65.65 ± 4.44 years, and the average disease duration was 4.55 ± 1.85 years. Besides, there were 10 males and 10 females in the endoscopy group; the age of patients was 67.30 ± 4.23 years, and the average disease duration was 4.95 ± 2.04 years. Collect and count surgical-related indicators, preoperative and postoperative radiologic findings, incision visual analog scale (VAS), lumbar and leg pain VAS, lumbar Japanese Orthopaedic Association (JOA), and Oswestry disability index (ODI) scores of all patients. RESULT: A series of surgical indicators (including the operation time, the quantity of bleeding, and postoperative hospital stay) in the endoscopy group was significantly lower than that in the control group (p < 0.05). The incision VAS score in the endoscopy group was also significantly lower than that in the control group at each time after surgery (p < 0.05). Besides, compared with the control group, in the endoscopy group, the leg pain VAS score and lumbar ODI score after surgery were significantly decreased (p < 0.05). Compared with the control group, in the endoscopy group, the lumbar JOA score was significantly higher (p < 0.05). CONCLUSION: Percutaneous endoscopic technique is a small trauma, quick recovery, safe, and effective minimally invasive surgery for patients with lumbar spinal stenosis secondary to ligamentum flavum hypertrophy.

Promoting effects of water on the NH3-SCR reaction over Cu-SAPO-34 catalysts: transient and permanent influences on Cu species.

Cu-SAPO-34 catalysts with varied Cu loadings were synthesized through ion exchange to study the influence of water on the NH3-SCR reaction. The catalytic activities were evaluated by selective catalytic reduction of NO under a reactant feed in the presence/absence of water. Transient experiments were designed to study the response of NO conversion to the presence of water. H2-TPR and DFT calculations were performed to study the reducibility of Cu species. NH3-TPD and XPS were conducted to reveal the migration of Cu species. The results show that water could remarkably improve NO reduction activities and the promoting effect is more significant on the catalyst with low Cu loading. Both transient and permanent influences were found in this promoting phenomenon. For the transient influence, water has been proved to accelerate the re-oxidation half-cycle. Moreover, water can enhance the promoting effect of the SCR feed on the migration of Cu species. These unanchored Cu ions migrate to defect sites to form active sites, which lead to a permanent influence of water.

Asymmetric Synthesis of Remote Quaternary Centers by Copper-Catalyzed Desymmetrization: An Enantioselective Total Synthesis of (+)-Mesembrine.

Catalytic asymmetric syntheses of remote quaternary stereocenters have been developed by copper-catalyzed 1,4-hydrosilylation of γ,γ-disubstituted cyclohexadienones. A variety of cyclohexenones have been synthesized in good yield and excellent enantioselectivity. Versatile 2-silyloxy diene intermediates bearing γ,γ-disubstituted all carbon stereogenic centers can be isolated from the mild reaction conditions. The utility of this strategy is exemplified in a catalytic asymmetric total synthesis of (+)-mesembrine.

Fungicidal effect of chitosan via inducing membrane disturbance against Ceratocystis fimbriata.

In this study, the fungicidal effects and detailed action of chitosan against Ceratocystis fimbriata were evaluated. The results demonstrated that chitosan exhibited strong antifungal activity that restricted the mycelium extension and changed the hyphal morphology. Fluorescein diacetate (FDA) and propidium iodide (PI) double-staining directly visualized decreased cell viability in response to chitosan treatment. Investigation of the PI influx showed that chitosan induced irreversible cell membrane damage. The efflux of potassium ions from the cytosol into the extracellular matrix demonstrated that chitosan induced the leakage of intracellular components. Massive intracellular bis-(1, 3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)] accumulation indicated the dissipation of membrane potential. Furthermore, chitosan clearly decreased the activity of H+/K+ ATPase. Fluorescence microscopy revealed that the fluorescence distribution and intensity of fluorescein isothiocyanate (FITC) changed as the incubation time increased. These results indicate that chitosan exerts a fungicidal effect via its ability to disturb fungal membranes.

Effect of O-chitosan nanoparticles on the development and membrane permeability of Verticillium dahliae.

Verticillium dahliae, which causes wilting in over 300 woody and herbaceous plant species, is a representative of fungal plant diseases for which effective controls are still needed. In this study, the antifungal action of oleoyl-chitosan nanoparticles was investigated against V. dahliae. Media containing oleoyl-chitosan nanoparticles dramatically decreased the mycelium growth. The highest antifungal indexes were observed on media amended with 2mg/mL nanoparticles. Optical microscopy showed that spore germination and hyphae morphology were affected. Scanning electron microscopy and transmission electron microscopy demonstrated degenerative alterations including crumpled hyphae and spores, thickened cell walls, disappeared membranous organelles, massive vacuolation of the cytoplasm, and cell wall-plasmalemma separation. Fluorescence microscopy showed that nanoparticles were internalized by fungal cells. The sharp increase in the release of intracellular components and decrease of total cellular protein concentration demonstrated damaged cell membranes. Overall, the results indicate that oleoyl-chitosan nanoparticles have the potential to control phytopathogens in agriculture.

Luminescence sensitization of Tb3+-DNA complexes by Ag.

Terbium ions (Tb3+) with unique photophysical properties have been utilized to develop biosensors with low background and high sensitivity. In this study, the Ag+-sensitized luminescence of Tb3+-DNA complexes was uncovered. The luminescence of Tb3+-DNA complexes could be enhanced by more than 30 times in the presence of Ag+, when Tb3+ was bound with poly(G) and poly(T) whereas not with other homopolymers. This research confirmed that the sensitization resulted from the interaction of Ag+ with certain bases involved in DNA, not just with the reported certain G-quadruplex sequence. The coordination of Ag+ to guanine and thymine bases was expected to increase their rigidities, form Tb3+-DNA-Ag+ ternary structures, and thus enhance energy transfer from guanine and thymine to Tb3+. These findings benefit the development of sensitive luminescence probes for various nucleic acids-related targets.

A highly Sensitive Turn-on Fluorescent Sensor for Ba2+ Based on G-Quadruplexes.

A G-quadruplex-based fluorescent biosensor for highly sensitive detection of barium ion (Ba2+) was constructed for the first time. In the absence of Ba2+, the G-quadruplex-specific fluorescence ligand N-methyl mesoporphyrin IX (NMM) remained weakly fluorescent when coexisted with a single-stranded G-quadruplex sequence AGRO100. Upon addition of Ba2+, AGRO100 was folded into G-quadruplex structures with the aid of Ba2+, which bound with NMM by stacking forces and significantly enhanced its fluorescence. The maximum fluorescence intensity of NMM was increased by ca. 22-fold in response to 1 µM Ba2+. This simple method exhibites a good linear relationship in the range of 0-600 nM with the detection limit of 4 nM. The detection method is turn-on, fast, economic, high in signal-to-noise ratio and free of participation of toxic organic solvents, demonstrating its great potential for on-site and real-time Ba2+ detection.

DNA Triplexes-Guided Assembly of G-Quadruplexes for Constructing Label-free Fluorescent Logic Gates.

Assembly of G-quadruplexes guided by DNA triplexes in a controlled manner is achieved for the first time. The folding of triplex sequences in acidic conditions brings two separated guanine-rich sequences together and subsequently a G-quadruplex structure is formed in the presence of K(+) . Based on this novel platform, label-free fluorescent logic gates, such as AND, INHIBIT, and NOR, are constructed with ions as input and the fluorescence of a G-quadruplex-specific fluorescent probe NMM as output.