Ratiometric fluorescence and smartphone-assisted sensing platform based on dual-emission carbon dots for brilliant blue detection.

In this study, an innovative ratiometric fluorescence and smartphone-assisted visual sensing platform based on blue-yellow dual-emission carbon dots (BY-CDs) was constructed for the first time to determine brilliant blue. The BY-CDs was synthesized via a facile one-step hydrothermal process involving propyl gallate and o-phenylenediamine. The synthesized BY-CDs exhibit favorable water solubility and exceptional fluorescence stability. Under excitation at 370 nm, BY-CDs show two distinguishable fluorescence emission bands (458 and 558 nm). Upon addition of brilliant blue, the fluorescence intensity at 558 nm exhibited a significant quenching effect attributed to fluorescence resonance energy transfer (FRET), while the fluorescence intensity at 458 nm was basically unchanged. The prepared BY-CDs can effectively serve as a ratiometric nanosensor for determining brilliant blue with the ratio of fluorescence intensities at 458 and 558 nm (F458/F558) as response signal. In addition, the developed ratiometric fluorescence sensor exhibits a noticeable alteration in color from yellow to green under UV light with a wavelength of 365 nm upon addition of varying concentrations of brilliant blue, which provides the possibility of visual detection of brilliant blue by a smartphone application. Finally, the BY-CDs based dual-mode sensing platform successfully detected brilliant blue in actual food samples and achieved a desirable recovery rate. This study highlights the merits of fast, convenient, economical, real-time, visual, high accuracy, excellent precision, good selectivity and high sensitivity for brilliant blue detection, and paves new paths for the monitoring of brilliant blue in real samples.

Identification of potential diagnostic and prognostic biomarkers for breast cancer based on gene expression omnibus.

BACKGROUND: Breast cancer is regarded as a highly malignant neoplasm in the female population, posing a significant risk to women's overall well-being. The prevalence of breast cancer has been observed to rise in China, accompanied by an earlier age of onset when compared to Western countries. Breast cancer continues to be a prominent contributor to cancer-related mortality and morbidity among women, primarily due to its limited responsiveness to conventional treatment modalities. The diagnostic process is challenging due to the presence of non-specific clinical manifestations and the suboptimal precision of conventional diagnostic tests. There is a prevailing uncertainty regarding the most effective screening method and target populations, as well as the specificities and execution of screening programs. AIM: To identify diagnostic and prognostic biomarkers for breast cancer. METHODS: Overlapping differentially expressed genes were screened based on Gene Expression Omnibus (GSE36765, GSE10810, and GSE20086) and The Cancer Genome Atlas datasets. A protein-protein interaction network was applied to excavate the hub genes among these differentially expressed genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, as well as gene set enrichment analyses, were conducted to examine the functions of these genes and their potential mechanisms in the development of breast cancer. For clarification of the diagnostic and prognostic roles of these genes, Kaplan-Meier and Cox proportional hazards analyses were conducted. RESULTS: This study demonstrated that calreticulin, heat shock protein family B member 1, insulin-like growth Factor 1, interleukin-1 receptor 1, Krüppel-like factor 4, suppressor of cytokine signaling 3, and triosephosphate isomerase 1 are potential diagnostic biomarkers of breast cancer as well as potential treatment targets with clinical implications. CONCLUSION: The screening of biomarkers is of guiding significance for the diagnosis and prognosis of the diseases.

A novel ratiometric fluorescent probe based on dual-emission carbon dots for highly sensitive detection of salicylic acid.

In this study, a novel ratiometric fluorescence probe based on dual-emission carbon dots (CDs) for the sensitive detection of salicylic acid (SA) was constructed for the first time. The dual-emission CDs were synthesized by simple hydrothermal method using tartaric acid (TA) and m-phenylenediamine (mPD) as raw materials. In the presence of SA, the fluorescence intensity of CDs was enhanced at 499 nm, but remained basically unchanged at 439 nm. This phenomenon is caused by the intermolecular hydrogen bond interactions. The concentrations of SA had an excellent linear relationship with CDs' fluorescence intensity ratio (F499/F439) in a range of 1 âˆ¼ 120 and 120 âˆ¼ 240 µM with low detection limits of 0.68 and 1.05 µM. The established ratiometric fluorescent probe is economical, simple and green, and can be used for the effective detection of SA. In addition, the proposed ratiometric fluorescent probe was successfully used to monitor SA in facial mask and toning lotion samples with a satisfactory recovery of 99.7-106.7 %. The results show that the constructed fluorescent probe based on dual-emission CDs has a great potential for the rapid and sensitive analysis of SA in actual samples.

A ratiometric sensor based on dual-emission carbon dots sensitive detection of amaranth.

Amaranth (AMA), a common food additive, is important to strictly control the content of food for the human body. In this paper, an innovative method based on intrinsic dual-emissive carbon dots (Y/B-CDs) was used to detect AMA. Y/B-CDs have two emission wavelengths at 416 and 544 nm with the excitation wavelength at 362 nm. The addition of AMA can rapidly quench the fluorescence of the two peaks with different degrees, and ratiometric detection can be achieved. Quantitative analysis showed two linear ranges of 0.1-20 µM and 20-80 µM, and detection limits are 42 and 33 nM, respectively. Moreover, good results were obtained for the detection of AMA in beverages and candy using Y/B-CDs. This suggests that the constructed sensor has the potential to detect AMA in real samples.

[Hydroxysafflor yellow A inhibits proliferation, migration, and chemoresistance of colorectal cancer cells through Akt/mTOR-autophagy pathway].

In recent years, the clinical treatment of colorectal cancer(CRC) has made great progress, but chemoresistance is still one of the main reasons for reducing the survival rate of patients with colorectal cancer. Therefore, ameliorating chemotherapy resis-tance is an urgent problem to be solved. The purpose of this study was to investigate the regulatory role and related molecular mechanisms of hydroxysafflor yellow A(HSYA) in colorectal cancer cell proliferation, migration, and 5-fluorouracil(5-FU) chemoresistance. In this study, HCT116 and HT-29 cells were used as research subjects. Firstly, methyl thiazolyl tetrazolium(MTT) assay and colony formation assay were used to detect and analyze the effect of HSYA on the proliferation of CRC cells. Secondly, the effect of HSYA on the cell cycle in CRC cells was analyzed by cell cycle assay. Furthermore, the effect of HSYA on the migration of CRC cells was analyzed by wound-healing assay and Transwell assay. Based on the above, the influences of HSYA on 5-FU chemoresistance of CRC cells and related molecular mechanisms were explored and analyzed. The results showed that HSYA significantly inhibited the proliferation and migration of CRC cells, and arrested the cell cycle in G_0/G_1 phase. In addition, HSYA significantly ameliorated the chemoresistance of CRC cells to 5-FU. The results of acridine orange staining and Western blot showed that the autophagy activity of CRC cells in the HSYA and 5-FU combined treatment group was significantly higher than that in the 5-FU single drug treatment group. As compared with the 5-FU single drug treatment group, the phosphorylation levels of protein kinase B(Akt) and mammalian target of rapamycin(mTOR) in the HSYA and 5-FU combined treatment group were significantly reduced, indicating that the Akt/mTOR signaling pathway in the combined treatment group was down-regulated in CRC cells. In conclusion, HSYA may upregulate autophagy activity through the Akt/mTOR signaling pathway, thereby inhibiting the proliferation and migration of CRC cells and ameliorating the chemoresistance to 5-FU.

A label-free fluorescence nanosensor based on nitrogen and phosphorus co-doped carbon quantum dots for ultra-sensitive detection of new coccine in food samples.

In this paper, an innovative method for the sensitive detection of new coccine using N, P-doped carbon quantum dots (N,P-CQDs) as fluorescent nanosensor is reported for the first time. The sensing mechanism is based on the fluorescence quenching of N,P-CQDs by new coccine through inner filter effect (IFE). N,P-CQDs were prepared by simple hydrothermal treatment of citric acid, phosphoric acid and ethylenediamine. Under the optimal conditions, the new coccine has two good linear responses in the concentration range of 0.2-100 and 100-200 µM, and the detection limits are as low as 24.8 and 9.4 nM, respectively. Our developed nanosensor has been successfully used for the determination of new coccine in food samples with good precision and high accuracy. This work highlights the economic, rapid, simple, selective and ultra-sensitive for new coccine detection, and opens up a new way for the monitoring of new coccine in actual food samples.

Selective colorimetric and fluorescence detection of nitroreductase enzymes in living cells.

Rhodamine dyes bearing aromatic nitro group has been synthesized for nitroreductase enzyme chemosensing applications. The probe is showing very selective turn-on fluorescent response towards nitroreductase enzymes and in hypoxic conditions. The sensor displays a remarkable fluorescent enhancement at 557 nm (λex = 500 nm) without the interference of other biologically relevant species under hypoxic conditions in a physiological medium. The nitro group in the sensor is reduced by the nitroreductase enzyme to the amino group, resulting in the hydrolysis of the probe and subsequent release of highly fluorescent rhodamine 6G dye is observed. This rhodamine based fluorescent probe has been utilized for the imaging of nitroreductase enzymes as well as hypoxia in live cells.

Highly selective and sensitive detection of amaranth by using carbon dots-based nanosensor.

In this work, a novel fluorescence nanosensor for selective and sensitive determination of amaranth was constructed using carbon dots (C-dots). Water soluble C-dots with strong fluorescence were obtained by a simple microwave-assisted method using urea and glycine as raw materials. It was found that amaranth can efficiently and sensitively quench the C-dots fluorescence by the inner filter effect (IFE) and non-radiative energy transfer (NRET) mechanisms. The fluorescence quenching efficiency (F 0/F) was strongly correlated with the concentration of amaranth in the 0.2-30 µM range. The detection limit (LOD) is 0.021 µM. There was no significant change in the fluorescence intensity of C-dots when other potentially interfering substances were present in the system. Our C-dots-based nanosensor was successfully utilized for the analysis of amaranth in drinks and showed rapid, sensitive and accurate responses. It indicates that the novel C-dots-based nanosensor has great potential in amaranth detection for real-life applications.

One-step synthesis of fluorescent carbon dots for sensitive and selective detection of hyperin.

In this article, we presented a new rapid, sensitive and selective method for the determination of hyperin (Hyp) based on the fluorescence quenching of fluorescent carbon dots (CDs). The CDs were prepared by simply mixing an aqueous solution of citric acid with diphosphorus pentoxide. This one-step synthetic route is fast and simple with neither high temperature nor complicated synthesis steps is involved. When Hyp was added to CDs solution, the fluorescence intensity of the CDs significantly decreased. The CDs display high selectivity for Hyp over many potentially interfering substances. Under the optimized conditions, a good linear relationship between the fluorescence intensity ratio Fo/F and the concentration of Hyp is obtained in a range of 0.22-55 µM with a detection limit (S/N = 3) of 78.3 nM. The method was successfully applied for the determination of Hyp in fufangmuji granules and human serum samples with recoveries in a range of 93.3-107.0%. This paper highlights the usefulness of CDs as an effective fluorescence probe for the Hyp detection due to its easy preparation, low-cost, excellent photostability, favorable biocompatibility and low cytotoxicity.

Fatal swine acute diarrhoea syndrome caused by an HKU2-related coronavirus of bat origin.

Cross-species transmission of viruses from wildlife animal reservoirs poses a marked threat to human and animal health 1 . Bats have been recognized as one of the most important reservoirs for emerging viruses and the transmission of a coronavirus that originated in bats to humans via intermediate hosts was responsible for the high-impact emerging zoonosis, severe acute respiratory syndrome (SARS) 2-10 . Here we provide virological, epidemiological, evolutionary and experimental evidence that a novel HKU2-related bat coronavirus, swine acute diarrhoea syndrome coronavirus (SADS-CoV), is the aetiological agent that was responsible for a large-scale outbreak of fatal disease in pigs in China that has caused the death of 24,693 piglets across four farms. Notably, the outbreak began in Guangdong province in the vicinity of the origin of the SARS pandemic. Furthermore, we identified SADS-related CoVs with 96-98% sequence identity in 9.8% (58 out of 591) of anal swabs collected from bats in Guangdong province during 2013-2016, predominantly in horseshoe bats (Rhinolophus spp.) that are known reservoirs of SARS-related CoVs. We found that there were striking similarities between the SADS and SARS outbreaks in geographical, temporal, ecological and aetiological settings. This study highlights the importance of identifying coronavirus diversity and distribution in bats to mitigate future outbreaks that could threaten livestock, public health and economic growth.

Comparison of single- and triple-injection methods for ultrasound-guided interscalene brachial plexus blockade.

Ultrasound-guided interscalene brachial plexus blockade (IBPB) has a relatively high success rate in shoulder surgery; however, whether multiple injections are superior to a single injection (SI) is currently unknown. In the present study, ultrasound-guided SI and triple-injection (TI) IBPBs were compared in a prospective randomized trial. A total of 111 patients undergoing arthroscopic shoulder surgery and presenting with an American Society of Anesthesiologists physical status grading of I-II were randomly allocated to receive IBPB with 15 ml of 1% ropivacaine as a SI or TI. Performance time, procedure-related pain scores, success rate and prevalence of complications were recorded. The distribution of sensory and motor block onset in the radial, median, ulnar and axillary nerves were assessed every 5 min until 30 min post-local anesthetic injection. The duration of sensory and motor blocks were also assessed. A significantly longer performance time was recorded in the TI group (P<0.001). No significant difference was observed in success rate (91% in TI vs. 88% in SI) 30 min post-injection, and the prevalence of complications and procedure-related pain were similar between the two groups. Sensory and motor blocks of the ulnar nerve in the TI group were significantly faster and more successful compared with the SI group at all time points (P<0.041). It was also observed that sensory and motor blocks in the TI group were prolonged compared with the SI group (P<0.041). In conclusion, the TI method exhibited a faster time of onset and resulted in a more successful blockade of the ulnar nerve. TI method may be a more effective approach for IBPB in a clinical setting.

Features of Ebola Virus Disease at the Late Outbreak Stage in Sierra Leone: Clinical, Virological, Immunological, and Evolutionary Analyses.

We performed Ebola virus disease diagnosis and viral load estimation for Ebola cases in Sierra Leone during the late stage of the 2014-2015 outbreak (January-March 2015) and analyzed antibody and cytokine levels and the viral genome sequences. Ebola virus disease was confirmed in 86 of 1001 (9.7%) patients, with an overall case fatality rate of 46.8%. Fatal cases exhibited significantly higher levels of viral loads, cytokines, and chemokines at late stages of infection versus early stage compared with survivors. The viruses converged in a new clade within sublineage 3.2.4, which had a significantly lower case fatality rate.

Genetic diversity and evolutionary dynamics of Ebola virus in Sierra Leone.

A novel Ebola virus (EBOV) first identified in March 2014 has infected more than 25,000 people in West Africa, resulting in more than 10,000 deaths. Preliminary analyses of genome sequences of 81 EBOV collected from March to June 2014 from Guinea and Sierra Leone suggest that the 2014 EBOV originated from an independent transmission event from its natural reservoir followed by sustained human-to-human infections. It has been reported that the EBOV genome variation might have an effect on the efficacy of sequence-based virus detection and candidate therapeutics. However, only limited viral information has been available since July 2014, when the outbreak entered a rapid growth phase. Here we describe 175 full-length EBOV genome sequences from five severely stricken districts in Sierra Leone from 28 September to 11 November 2014. We found that the 2014 EBOV has become more phylogenetically and genetically diverse from July to November 2014, characterized by the emergence of multiple novel lineages. The substitution rate for the 2014 EBOV was estimated to be 1.23 × 10(-3) substitutions per site per year (95% highest posterior density interval, 1.04 × 10(-3) to 1.41 × 10(-3) substitutions per site per year), approximating to that observed between previous EBOV outbreaks. The sharp increase in genetic diversity of the 2014 EBOV warrants extensive EBOV surveillance in Sierra Leone, Guinea and Liberia to better understand the viral evolution and transmission dynamics of the ongoing outbreak. These data will facilitate the international efforts to develop vaccines and therapeutics.

[Utility of high throughput sequencing technology in analyzing the terminal sequence of caudovirales bacteriophage genome].

To confirm the hypothesis that the high frequency sequences of high throughput sequencing are the terminal sequences of the bacteriophage genome. An adaptor of specific sequence was linked to the end of the bacteriophage T3 genomic DNA, which was then subject to high throughput sequencing; as a control, the same T3 genomic DNA without adaptor was also analyzed by high throughput sequencing. The sequencing results were examined with bioinformatics software. Similar high throughput sequencing technique was applied to analyze the genomic sequence of N4-like bacteriophage IME11. Bioinformatics study showed that the sequences tagged with adaptors were consistent with the high frequency sequences without adaptor labeling. Our analysis also indicated that the end of the T4-like phage genome had specific sequences instead of random sequences, disagreeing with the previous assertion. Evidences were provided that N4-like bacteriophage had a particular terminal sequence: the left end of the genome was unique while the right end was permuted. The high throughput sequencing technique was convenient and practical to be used to simultaneously detect the terminal sequence and the complete sequence of bacteriophage genome.

Altitudinal variation in age and body size in Yunnan pond frog (Pelophylax pleuraden).

Large-scale systematic patterns of body size are a basic concern of evolutionary biology. Identifying body size variation along altitudinal gradients may help us to understand the evolution of life history of animals. In this study, we investigated altitudinal variation in body size, age and growth rate in Chinese endemic frog, Pelophylax pleuraden. Data sampled from five populations covering an altitudinal span of 1413 to 1935 m in Sichuan province revealed that body size from five populations did not co-vary with altitudes, not following Bergmann's rule. Average adult SVL differed significantly among populations in males, but not in females. For both sexes, average adult age differed significantly among populations. Post-metamorphic growth rate did not co-vary with altitude, and females grew faster than males in all populations. When controlling the effect of age, body size did not differ among populations in both sexes, suggesting that age did not affect variation in body size among populations. For females, there may be other factors, such as the allocation of energy between growth and reproduction, that eliminated the effect of age on body size. To our minds, the major reason of body size variation among populations in male frogs may be related to individual longevity. Our findings also suggest that factors other than age and growth rate may contribute to size differences among populations.

Testis asymmetry and sperm length in Rhacophorus omeimontis.

Theory predicts that the degree of testes asymmetry should be positively correlated with male body condition in species with directional testis asymmetry. We tested this prediction in Rhacophorus omeimontis, a species in which females mate with more than one male. Our results showed that the treefrogs did not exhibit the absence of directional asymmetry in testis size, but rather the occurrence of fluctuating asymmetry. Moreover, we also tested differences in body size, body mass, testis mass, testis asymmetry, and sperm size among initially paired, jointly paired, and unpaired males. We found that body size and mass, testis mass, testis asymmetry and sperm length did not differ among the three male types. Testis mass showed a positive relationship with soma mass, but the correlations between the extent of fluctuating testis asymmetry and sperm length, and between testis mass and sperm length were not significant. Our data suggest that testes size and sperm length do not play an important role in determining male mating success in the presence of sperm competition.

Close relationship between the 2009 H1N1 virus and South Dakota AIV strains.

Although previous publications suggest the 2009 pandemic influenza A (H1N1) virus was reassorted from swine viruses of North America and Eurasia, the immediate ancestry still remains elusive due to the big evolutionary distance between the 2009 H1N1 virus and the previously isolated strains. Since the unveiling of the 2009 H1N1 influenza, great deal of interest has been drawn to influenza, consequently a large number of influenza virus sequences have been deposited into the public sequence databases. Blast analysis demonstrated that the recently submitted 2007 South Dakota avian influenza virus strains and other North American avian strains contained genetic segments very closely related to the 2009 H1N1 virus, which suggests these avian influenza viruses are very close relatives of the 2009 H1N1 virus. Phylogenetic analyses also indicate that the 2009 H1N1 viruses are associated with both avian and swine influenza viruses circulating in North America. Since the migrating wild birds are preferable to pigs as the carrier to spread the influenza viruses across vast distances, it is very likely that birds played an important role in the inter-continental evolution of the 2009 H1N1 virus. It is essential to understand the evolutionary route of the emerging influenza virus in order to find a way to prevent further emerging cases. This study suggests the close relationship between 2009 pandemic virus and the North America avian viruses and underscores enhanced surveillance of influenza in birds for understanding the evolution of the 2009 pandemic influenza.

[Construction of HCV-producing cell model based on self-cleaving ribozyme].

OBJECTIVES: To construct a stable HCV-producing cell model for anti-HCV drug research. METHODS: The HCV-ribozyme recombinant plasmid pJFH1-Rbz was constructed to generate the exact 5' and 3' ends of HCV genomic RNA by placing two self-cleaving ribozymes at both ends of the HCV JFH-1 cDNA. The plasmid was then transfected into HepG2 cells and the resultant clones were screened with G418. Subsequently, immunofluorescence and Western blot were performed to detect the expression of HCV core protein, HCV RNA level was quantitated by TaqMan real-time PCR method and HCV particles was detected by electron microscopy. RESULTS: HCV core protein was detected in the screened cell clone, and the level of HCV RNA was up to 1000,0000 copies/ml in the culture medium. Electron microscopy showed the viral particles in the culture suspension were approximately 55 nm in diameter. IFN-treating experiment demonstrated that the HCV RNA level decreased with the increasing concentration of IFN alpha. CONCLUSION: We constructed a stable HCV-producing cell model which can be used for anti-HCV drug research.