Associations between ATG16L1 gene polymorphism and antineutrophil cytoplasmic antibody-associated vasculitis in the Chinese Guangxi population: A case-control study.

BACKGROUND: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease often accompanied by rapidly progressive renal failure, and the genetic background is still unknown. Our study was performed to test whether autophagy-related 16 like 1 (ATG16L1) rs4663402 and rs4663396 single nucleotide polymorphisms (SNPs) were associated with AAV in the Chinese Guangxi population. METHODS: One hundred seventy seven unrelated AAV patients and 216 healthy controls were included in this case-control study. Multiplex polymerase chain reaction combined with high-throughput sequencing was used for typing, and SNPStats and SHEsis were used for association analysis, pairwise linkage disequilibrium, and haplotype analysis. RESULTS: rs4663402 and rs4663396 were in Hardy-Weinberg equilibrium in AAV and control groups. The frequencies of rs4663402 AA, AT, and TT genotypes were 82.5%, 16.9%, and 0.6%, respectively, in patients with AAV, and 83.5%, 16.2%, and 0.5%, respectively, in controls. The frequencies of rs4663396 CC, CT, and TT genotypes were 63.8%, 33.9%, and 2.3%, respectively, in patients with AAV, and 69.2%, 26.6%, and 4.2%, respectively, in controls. Haplotype analysis revealed two SNPs in a single haplotype block (D' = 1.0). Our logistic regression adjusted for sex and age showed no association between rs4663402 and rs4663396 and the risk for AAV in genetic models (p > 0.05). However, ATG16L1 rs4663396 CC and CT + TT genotypes exhibited statistically significant differences in the incidence of arthralgia (p = 0.03). CONCLUSIONS: Our results indicated that ATG16L1 rs4663402 and rs4663396 polymorphisms were not associated with AAV in the Chinese Guangxi population. ATG16L1 rs4663396 CT + TT genotype may be associated with arthralgia.

Insufficient ventilation led to a probable long-range airborne transmission of SARS-CoV-2 on two buses.

Uncertainty remains on the threshold of ventilation rate in airborne transmission of SARS-CoV-2. We analyzed a COVID-19 outbreak in January 2020 in Hunan Province, China, involving an infected 24-year-old man, Mr. X, taking two subsequent buses, B1 and B2, in the same afternoon. We investigated the possibility of airborne transmission and the ventilation conditions for its occurrence. The ventilation rates on the buses were measured using a tracer-concentration decay method with the original driver on the original route. We measured and calculated the spread of the exhaled virus-laden droplet tracer from the suspected index case. Ten additional passengers were found to be infected, with seven of them (including one asymptomatic) on B1 and two on B2 when Mr. X was present, and one passenger infected on the subsequent B1 trip. B1 and B2 had time-averaged ventilation rates of approximately 1.7 and 3.2 L/s per person, respectively. The difference in ventilation rates and exposure time could explain why B1 had a higher attack rate than B2. Airborne transmission due to poor ventilation below 3.2 L/s played a role in this two-bus outbreak of COVID-19.

Polar Solvent Induced Lattice Distortion of Cubic CsPbI3 Nanocubes and Hierarchical Self-Assembly into Orthorhombic Single-Crystalline Nanowires.

Despite the recent surge of interest in inorganic lead halide perovskite nanocrystals, there are still significant gaps in their stability disturbance and the understanding of their destabilization, assembly, and growth processes. Here, we discover that polar solvent molecules can induce the lattice distortion of ligand-stabilized cubic CsPbI3, leading to the phase transition into orthorhombic phase, which is unfavorable for photovoltaic applications. Such lattice distortion triggers the dipole moment on CsPbI3 nanocubes, which subsequently initiates the hierarchical self-assembly of CsPbI3 nanocubes into single-crystalline nanowires. The systematic investigations and in situ monitoring on the kinetics of the self-assembly process disclose that the more amount or the stronger polarity of solvent can induce the more rapid self-assembly and phase transition. These results not only elucidate the destabilization mechanism of cubic CsPbI3 nanocrystals, but also open up opportunities to synthesize and store cubic CsPbI3 for their practical applications in photovoltaics and optoelectronics.

[Impact of deep slow-wave sleep deprivation on oxidative stress response of the testis tissue in rats].

OBJECTIVE: To investigate the influence of deep slow-wave sleep deprivation on the oxidative stress of testicular tissue in rats. METHODS: Thirty-six 5-week-old male Wistar rats were equally randomized into deep slow-wave sleep deprivation group (SD1), deep slow-wave sleep and duration sleep deprivation group ( SD2), and a cage control group (CC). The rat model of deep slow-wave sleep deprivation was established using the flowerpot technique. The rats in the SD1 group were interfered every 24 minutes and deprived of 12 hours of sleep at night, those in the SD2 group deprived of 8 minutes of sleep at an interval of 24 minutes and 12 hours of sleep at night, and those in the CC group exposed to 12 hours of daylight and 12 hours of darkness. After 28 days, all the rats were executed for measurement of the testis volume and protein content, determination of the methane dicarboxylic aldehyde (MDA) level and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and observation of the pathological changes in the testicular tissue under the microscope. RESULTS: Compared with the CC group, the rats in the SD1 and SD2 groups showed significantly reduced body weight (ï¼»268.5 ± 1.6ï¼½ vs ï¼»248.1 ± 25.1ï¼½andï¼»232.9 ± 10.1ï¼½g, P<0.05) and increased relative testis mass (ï¼»50.0 ± 1.3ï¼½ vs ï¼»57.9 ± 6.1ï¼½ and ï¼»54.9 ± 3.5ï¼½ ×10⁻², P<0.05). Statistically significant differences were found between the CC and SD2 groups in the contents of protein (ï¼»6.3 ± 1.4ï¼½ vs ï¼»4.5 ± 0.9ï¼½ gpro/L, P<0.05) and MDA (ï¼»1.1 ± 0.1ï¼½ vs ï¼»1.3 ± 0.3ï¼½ nmol/mgpro, P<0.05) and the activities of SOD (ï¼»104.3 ± 33.1ï¼½ vs ï¼»135.2 ± 26.9ï¼½ U/mgpro, P<0.05) and GSH-Px (ï¼»15.6 ± 4.0ï¼½ vs ï¼»21.7 ± 4.3ï¼½ U/mgpro, P<0.05), but not between the CC and SD1 groups (P>0.05). The lumens in the testis were narrowed, with obvious hyperplasia, hyperemia and edema in the peripheral interstitial tissue, but no significant pathologic changes were observed in the testis tissue of the SD1 group. CONCLUSIONS: Long-term deprivation of deep slow-wave sleep impairs the structure of the testis tissue and induces oxidative stress response in rats.

Decolorization of RhB dye by manganese oxides: effect of crystal type and solution pH.

BACKGROUND: Organic dye pollution in water has become a major source of environmental pollution. Mn(III/IV) oxides have attracted a great deal of attention to remove organic dye pollutants due to their unique structures and physicochemical properties. Numerous studies have reported the removal of dye by various Mn(III/IV) oxides through catalytic degradation and adsorption. The crystalline structures of manganese oxides and solution pH may exert substantial impact on the removal of dyes. However, few studies have focused on the oxidative degradation of RhB dye using Mn(III/IV) oxides with different crystal structures during a spontaneous reaction. In the present study, three manganese oxides with different crystal type (α-MnO2, ß-MnO2, and δ-MnO2) were prepared by refluxing process to decolorize RhB dye in various pH solutions. RESULTS: The results showed that the decolorization efficiencies of RhB for the three manganese oxides all increase with decrease solution pH. α-MnO2 exhibited highest activity and could efficiently degrade RhB at pH 2-6. The degradation of RhB by ß-MnO2 and δ-MnO2 could be observed at pH 2-3, and only little adsorption RhB on manganese oxides could be found at pH 4-6. The UPLC/MS analysis suggests that the decolorization of RhB by manganese oxides consists of three main stages: (1) cleavage of the ethyl groups from RhB molecular to form Rh; (2) further destruction of -COOH and -CNH2 from Rh to form the small molecular substances; (3) mineralization of the small molecular substances into CO2, H2O, NO3 (-) and NH4 (+). CONCLUSIONS: Overall, these results indicate that α-MnO2 may be envisaged as efficient oxidants for the treatment of organic dye-containing wastewater under acid conditions.

Antitumor mechanism of kangliu pill on gliomas in mice through PI3K-Akt signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Gliomas are common malignant intracranial tumors that have worse prognosis and pose a serious threat to human health. The Kangliu pill (KLP) is an innovative herbal compound from Xuanwu Hospital of Capital Medical University that has been clinically used for the treatment of gliomas for more than 40 years, and is one of the few drugs for primary treatment of this disorder. But the fundamental molecular mechanisms and pathways of KLP are not clear. AIM OF THE STUDY: To investigate the therapeutic mechanism of KLP in the treatment of gliomas. MATERIALS AND METHODS: An in situ xenograft model of red fluorescent protein-labeled human glioma cell line (U87-RFP) in BALB/c-nu mouse was established, and the therapeutic effect of KLP on gliomas was assessed by tumor weights and fluorescence areas. A quantitative proteomics approach using tandem mass tags combined with liquid chromatography-tandem mass spectrometry was performed to explore differentially expressed proteins (DEPs) in glioma tissues, and bioinformatics analyses including Gene Ontology analysis, pathway analysis, and network analysis were performed to analyze the proteins involved in the network therapeutic mechanisms responsible for key metabolic pathways. Cytological experiments corroborated the above analysis results. RESULTS: Network pharmacology approach screened 246 bioactive compounds contained in KLP, targeting 724 proteins and 173 potential targets of KLP for glioma treatment. The important targets obtained after visualizing the PPI network were AKT1, INS, GAPDH, SRC, TP53, etc. The KEGG enrichment results showed that 9 proteins were related to cancer, including Pathways in cancer, PI3K/AKT signaling pathway, etc. KLP had antitumor activity in gliomas, which reduced tumor weights and fluorescence areas. A number of DEPs possibly associated with gliomas were identified through quantitative proteomic techniques. Among these DEPs, 50 (25 upregulated and 25 downregulated) were identified that might be associated with KLP action. Bioinformatics showed that these 50 DEPs were mainly focused on focal adhesion, extracellular matrix (ECM)-receptor interactions, and the PI3K-Akt signaling pathway. Cytological experiments revealed that KLP significantly inhibited the proliferation and promoted apoptosis of U87-MG human glioma cells, and its mechanism was through the inhibition of PI3K/AKT signaling pathway. CONCLUSION: Therapeutic effect of KLP was regulation of multiple pathways in the treatment of gliomas. In specific, it interacts through the PI3K-Akt signaling pathway. This work may contribute proteomic insights for further research on the medical treatment of glioma using KLP.

Interface-Mediated Mechanoluminescence Enhancement from Heterojunction Phosphors: Experiment and Theory.

Mechanoluminescence (ML) phosphors have made significant progress in various fields, such as artificial intelligence, the Internet of Things, and biotechnology. However, enhancing their weak ML intensity still remains a challenge. Here, we report a new series of Na1-xMgxNbO3:Pr3+ (x = 0.00, 0.10, 0.20, 0.40, 0.60, 0.80, and 1.00 mol %) heterojunction systems, which exhibit significant ML enhancement as compared with either the Pr3+-doped NaNbO3 or MgNbO3, and the physical mechanisms behind the ML enhancement have been explored comprehensively from both the experiment and theory points of view. Experimental tests, including thermoluminescence and positron annihilation lifetime measurements, combined with first-principles calculations, consistently indicate that the ML enhancement observed in these newly reported systems is due to the formation of heterojunctions, which plays a crucial role in modulating the defect configuration of the phosphors and facilitating efficient charge transfer. By controlling the Na/Mg ratio in conjunction with Pr3+ doping, continuous changes in the band offset and the concentrations of certain types of traps in the forbidden gap are achieved, leading to the optimum conditions in the 8/2 ratio samples. These findings demonstrate a novel type of ML phosphor and provide a theoretical basis for the design of high-performance ML phosphor.

[Toxicity Testing Organisms for Marine Ecotoxicological Research in China].

Since the late 1970s, marine ecotoxicology began to sprout and develop in China. Based on the principles of dose-response relationships, some marine organisms are used in toxicity tests to evaluate the impact of marine pollutants on marine organisms and marine ecosystems. At the early stage, marine ecotoxicological research mainly focused on the bioaccumulation, biomagnification, and biodegradation of traditional pollutants such as heavy metals, radioactive elements, organotin, petroleum hydrocarbons, and pesticides, as well as their toxic effects on survival, growth, and other physiological indicators. With the development of Chinese industry, marine pollution has become increasingly serious. In addition to the traditional marine pollutants, toxicological research has been conducted on emerging pollutants with potential risks to marine ecosystems, such as POPs, emerging organic pollutants, nanomaterials, and microplastics. Moreover, the species of marine organisms used in toxicity testing have become more diverse. The selection of testing organisms is essential for evaluating toxicity correctly. The toxicity tests should be conducted on a variety of organisms from different trophic levels to ensure the comprehensive understanding of the impact of pollutants on marine ecosystems. The major types of marine organisms used in the toxicity testing include marine alga, protozoa, rotifera, annelida, mollusc, echinoderma, arthropoda, cephalopoda, and marine fish, which have been used in the toxicological studies of various marine pollutants. The outcome results can serve as the scientific basis for the ecological risk assessment of marine pollutants and the establishment of seawater quality criteria. It should be noted that the sensitivity of different testing organisms to different types of pollutants is quite diverse. Therefore, in addition to conducting a battery of tests on a variety of species which play important roles in marine ecosystems, elucidating the toxic mechanisms in different species is also important for marine ecotoxicological studies. The application of the above-mentioned organisms in marine ecotoxicology research in recent years is briefly reviewed here. Particularly, the six commonly used marine model species (Skeletonema costatum, Euplotes vannus, oysters, sea urchins, Tigriopus japonicus, and Oryzias melastigma) used in toxicity testing are introduced in detail.

Metarhizium anisopliae is a valuable grist for biocontrol in beta-cypermethrin-resistant Blattella germanica (L.).

BACKGROUND: The widespread use of chemical insecticides has resulted in the development of resistance in German cockroaches worldwide, and biopesticides based on entomopathogenic fungi as active ingredients have become a promising alternative strategy. Resistance can change many of the physiological and biochemical characteristics of insect pests, such as cuticle thickness, detoxification enzyme activity, and even intestinal flora composition. Thus, potential interactions between pathogenic fungi and insecticide resistance may lead to unpredictable changes in pest susceptibility to fungi. RESULTS: Beta-cypermethrin-resistant German cockroaches were more susceptible to infection with the fungus Metarhizium anisopliae regardless of age and sex. Histopathological results showed that the infection of resistant strains (R) by M. anisopliae was visibly faster than that of susceptible strains (S). The gut microbiota of the S strain indicated a stronger ability to inhibit fungi in vitro. The abundance of Parabacteroides, Lachnoclostridium, and Tyzzerella_3 decreased significantly in the R strain, and most demonstrated the ability to regulate glucose and lipid metabolism, and antifungal infections. The expression levels of Akirin, BgTPS, and BgPo genes in the R strain were significantly lower than those in the S strain, while BgChi and CYP4G19 gene expression were significantly higher. The mortality of cockroaches infected with M. anisopliae decreased to varying degrees after RNA interference, reflecting the role of these genes in antifungal infection. CONCLUSIONS: Results confirmed that insecticide resistance may enhance cockroach susceptibility to fungi by altering intestinal flora and gene expression. Fungal biopesticides have high utilization value in pest control and insecticide resistance management strategies. © 2021 Society of Chemical Industry.

Down-Regulation of AHNAK2 Inhibits Cell Proliferation, Migration and Invasion Through Inactivating the MAPK Pathway in Lung Adenocarcinoma.

AHNAK nucleoprotein 2 (AHNAK2) has been emerged as a crucial protein for neuroblast differentiation and cell migration, thereby involving in the development of various cancers. However, the specific molecular mechanism of AHNAK2 in lung adenocarcinoma is inconclusive. By accessing to the Oncomine dataset and GEPIA website, a higher expression level of AHNAK2 was observed in lung adenocarcinoma tissue samples. Overall survival (OS) curve plotted by Kaplan-Meier method showed that up-regulation of AHNAK2 was related with poor prognosis of lung adenocarcinoma patients. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis and western blot were conducted to examine the expression level of genes in lung adenocarcinoma cells. Through functional in vitro experiments, cell proliferation, migration and invasion were all suppressed after AHNAK2 knockdown using Cell counting kit-8 (CCK-8) assay, wound-healing and transwell analysis. Reduction of AHNAK2 decreased the apoptosis rate using flow cytometry analysis. Moreover, the key markers of MAPK pathway, p-MEK, p-ERK and p-P90RSK were decreased due to the transfection of si-AHNAK2 in A549 cells. U0126, a MEK inhibitor, showed the similar effects on MAPK-related protein levels with si-AHNAK2. To sum up, AHNAK2 is significantly increased in lung adenocarcinoma and plays a carcinogenic role by activating the MAPK signaling pathway, providing a novel insight and raising possibility for lung adenocarcinoma treatment.

Transmission of SARS-CoV-2 in Public Transportation Vehicles: A Case Study in Hunan Province, China.

Here we report a case study of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak event during bus trips of an index patient in Hunan Province, China. This retrospective investigation suggests potential airborne transmission of SARS-CoV-2 and the possibility of superspreading events in certain close contact and closed space settings, which should be taken into account when control strategies are planned.

Tunable Mie Resonances of Tin-based Iodide Perovskite Islandlike Films with Enhanced Infrared Photoluminescence.

The ability of light manipulation at a sub-wavelength scale of metal halide perovskite-based nanostructures through nanophotonic design were employed for advanced optical and optoelectronic applications. While these nanostructures could be efficiently tuned in the visible spectral range, their operation at infrared wavelengths is still challenging. Herein, we illustrate that islandlike films of lead-free CH3NH3SnI3 can generate strong and tunable Mie-type resonances in the near-infrared spectral range. Two critical factors contribute to the Mie resonance properties-the microscale geometry is crucial for the initiation of Mie resonances in the particles, while the concentration of free holes formed via the oxidation of Sn2+ to Sn4+ modulates the spectral position of Mie resonances. Moreover, coupling the Mie resonances to the photoluminescence peak wavelength results in the enhancement of the photoluminescence intensity. This study offers a platform for the implementation of optically resonant perovskite nanostructures as tunable light emitters for infrared photonics and optoelectronics.

[COX-2 and HO-1 are involved in the delayed preconditioning elicited by bradykinin in rat hearts].

OBJECTIVE: To investigate whether cyclooxygenase-2 (COX-2) and heme oxygenase-1 (HO-1) are involved in the bradykinin-induced delayed protection. METHODS: Cardiac contractility, lactate dehydrogenase (LDH) and infarct area were analyzed in isolated rat hearts undergoing ischemia-reperfusion injury induced by Langendorff method. RESULT: Conscious rats received bradykinin (40 microg/kg), and the isolated hearts were subjected to 30 min of regional ischemia and 120 min of reperfusion 24 h later. Bradykinin pretreatment would improve post-ischemic performance, and reduced the release of LDH and infarct size. COX-2 inhibitor celecoxib (3 mg/kg) abolished bradykinin-induced protection, leading to poorer myocardial performance, release of more LDH and larger infarct sizes. Administration of HO-1 inhibitor ZnPP IX(20 microg/kg) before bradykinin partially abrogated the delayed protection. Pretreatment with the mitochondrial ATP sensitive potassium channel(mitoK(ATP) antagonist 5-HD before or 24 h after bradykinin administration also abolished the effect of protection. CONCLUSION: The results indicate that activation of HO-1 and COX-2 might be involved in the delayed cardioprotection evoked by bradykinin, and mitoK(ATP) channel may serve as both a trigger and a mediator in the cardioprotection.

Relationship between carbachol hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen or NF-kappaB activation in rats in vitro.

The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen activation or NF-kappaB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-kappaB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10(-3) mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P < 0.01) following the treatment with a high concentration of carbachol (10(-3) mol/L) in vitro. The addition of 10(-2) mol/L PDTC didn't result in a significant decrease in the activity of trypsin and the leakage of LDH from pancreatic acinar cells treated with a high concentration of carbachol (10(-3) mol/L) in vitro (P > 0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-kappaB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.

[Raman spectra study on the GeS2-Ga2S3-KCl system glasses].

Raman spectra of GeS2 -Ga2S3-KCl pseudo-ternary system glasses at room temperature in the air were probed systematically in the region of 150-500 cm(-1). Based on the results of Raman spectra and preparing procedure in pseudo-binary systems GeS2 -KCl and Ga2S3 -KCl, the sole interaction of Ga2S3 and KCl was identified and new units GaS3/2 Cl were produced in GeS2 -Ga2S3-KCl glasses. That K+ ions in the form of Cl as the nearest coordination were homogeneously dispersed in the polymeric network was confirmed by the Raman spectra evolution of samples on the serials I and Ill. Raman spectral evolution of three composition serials can be successfully interpreted using a localized model considering the effect of K+ ions on the structural units GaS3/2 Cl and Ga2 S4 Cl2.

Clinical investigation of TROP-2 as an independent biomarker and potential therapeutic target in colon cancer.

Colon cancer is associated with a severe demographic and economic burden worldwide. The pathogenesis of colon cancer is highly complex and involves sequential genetic and epigenetic mechanisms. Despite extensive investigation, the pathogenesis of colon cancer remains to be elucidated. As the third most common type of cancer worldwide, the treatment options for colon cancer are currently limited. Human trophoblast cell­surface marker (TROP­2), is a cell­surface transmembrane glycoprotein overexpressed by several types of epithelial carcinoma. In addition, TROP­2 has been demonstrated to be associated with tumorigenesis and invasiveness in solid types of tumor. The aim of the present study was to investigate the protein expression of TROP­2 in colon cancer tissues, and further explore the association between the expression of TROP­2 and clinicopathological features of patients with colon cancer. The expression and localization of the TROP­2 protein was examined using western blot analysis and immunofluorescence staining. Finally, the expression of TROP­2 expression was correlated to conventional clinicopathological features of colon cancer using a χ2 test. The results revealed that TROP­2 protein was expressed at high levels in the colon cancer tissues, which was associated with the development and pathological process of colon cancer. Therefore, TROP­2 may be used as a biomarker to determine the clinical prognosis, and as a potential therapeutic target in colon cancer.

Interactions of paralytic shellfish toxins with xenobiotic-metabolizing and antioxidant enzymes in rodents.

Paralytic shellfish toxins (PSTs) are neurotoxins known to block voltage-gated sodium channels in intoxicated animals and humans. Their metabolism in mammalian systems and their effects on other receptors are not as well understood. In this study, we investigated the in vitro metabolism of two classes of PSTs, gonyautoxin 2/3 (GTX2/3) and C1/2 toxins (C1/2), using rat and mouse liver enzyme preparations. We also analyzed the effects of these toxins on several antioxidant and xenobiotic-metabolizing enzymes in mice. These toxins were selected for their prevalence in the coastal waters of Southern China. When the toxins were incubated with liver preparations containing Phase I and Phase II xenobiotic metabolizing enzymes and appropriate co-factors, no transformation of the toxins was detectable. When mice were given sub-lethal doses of GTX2/3, a loss of activity was observed in hepatic ethoxyresorufin-O-deethylase, penthoxyresorufin-O-deethylase, glutathione peroxidase and superoxide dismutase, but not in glutathione S-transferase, catalase and glutathione reductase. Exposure to the same mouse units of C1/2 caused only a slight reduction in the activity of penthoxyresorufin-O-deethylase and glutathione peroxidase. Our results indicated that these toxins may not be metabolized readily in mammals and that they may cause adverse effects other than sodium channel blocking.

Sensitive single-color fluorescence "off-on" switch system for dsDNA detection based on quantum dots-ruthenium assembling dyads.

Due to the high importance of detecting DNA with both fast speed and high sensitivity, we proposed a new dsDNA detection method relying on a novel single-color fluorescence "off-on" switch system. Water-soluble glutathione capped CdTe QDs (emission at 605 nm) was prepared for taking advantage of the readily tunable emission property of QDs. Initially, QDs was completely quenched by the Ru(phen)2(dppz)(2+), as the spontaneous formation of QDs-Ru assembling dyads. Then, in the case of the addition of dsDNA, the Ru(phen)2(dppz)(2+) was removed away from the CdTe QDs, producing free CdTe QDs and the Ru-dsDNA complex. Both of them could be excited at the same wavelength and emit overlaid fluorescence. This single-color fluorescence "off-on" signal was sensitive to the concentration of dsDNA. Native dsDNA with the concentration of 10 pg/mL could be detected when 0.5 nM CdTe QDs was used, and ssDNA, RNA or BSA had no interference on it. With this system, the dsDNA samples of hepatitis B virus (HBV) patients were tested. The results were in good agreement with those detected by fluorescence quantitative PCR (P>0.05), and for those samples with very low DNA concentrations, this system could provide more accurate results, demonstrating the possible clinical applicability of this "off-on" switch system. For this system, chemical conjugation or labeling of probes is not required, and unmodified native DNA targets could be detected in less than half an hour. Therefore, a simple, fast, sensitive, low cost, highly selective and practically applicable detection system for dsDNA has been described.