Sensitive colorimetric assay of T4 DNA ligase by the oxidase nanozyme of LaMnO3.26 coupled with a hyperbranched amplification reaction.

The development of efficient methods for the detection of T4 DNA ligase is extremely important for public health. The present work demonstrates the integration of engineerable oxidase nanozyme of LaMnO3.26 nanomaterials for the colorimetric detection of T4 DNA ligase. Specifically, the LaMnO3.26 nanomaterials exhibited oxidase-like activity, oxidizing o-phenylenediamine (OPD), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), and 3,3',5,5'-tetramethylbenzidine (TMB) to their corresponding oxidation products, which featured maximum absorption wavelengths at 450, 417 and 650 nm, respectively, while pyrophosphate ion (PPi) caused an obvious decrease in the oxidase-like activity of LaMnO3.26 through its surface coordination with the surface-exposed Mn element and induced aggregation of the nanozyme. Attributed to the PPi regulated oxidase nanozyme activity, LaMnO3.26 served as a colorimetric probe for the quantitative detection of T4 DNA ligase assisted by a hyperbranched amplification reaction for signal amplification. The T4 DNA ligase was detected with a linear range of 4.8 × 10-3 to 6.0 U mL-1, achieving a detection limit of 1.6 × 10-3 U mL-1. The outcome indicated that the developed nanozyme might be extended to a broad range of practical applications.

Agriterribacter soli sp. nov., isolated from herbicide-contaminated soil.

A Gram-stain-negative, non-spore-forming and rod-shaped bacterium, designated strain NS-102T, was isolated from herbicide-contaminated soil sampled in Nanjing, PR China, and its taxonomic status was investigated by a polyphasic approach. Cell growth of strain NS-102T occurred at 16-42 °C (optimum, 30 °C), at pH 5.0-8.0 (optimum, pH 6.0) and in the presence of 0-3.5 % (w/v) NaCl (optimum, without addition of NaCl). The 16S rRNA gene sequence of strain NS-102T shows high similarity to that of Agriterribacter humi YJ03T (96.9 % similarity), followed by Terrimonas terrae T16R-129T (93.8 %) and Terrimonas pekingensis QHT (93.6 %). Average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between the draft genomes of strain NS-102T and A. humi YJ03T were 72.5, 69.4 and 18.6%, respectively. The only respiratory quinone was MK-7, and phosphatidylethanolamine and unidentified lipids were the major polar lipids. The major cellular fatty acids of strain NS-102T contained high amounts of iso-C15 : 0 (24.6 %), iso-C17 : 03-OH (24.1 %), iso-C15 : 0 G (16.6 %) and summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) (15.6 %). The G+C content of the total DNA was determined to be 40.0 mol%. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain NS-102T represents a novel species of the genus Agriterribacter, for which the name Agriterribacter soli sp. nov. is proposed. The type strain is NS-102T (=CCTCC AB 2017249T=KCTC 62322T).

Self-coordinated nanozyme on Cu3BiS3 nanorods for high-performance aptasensing.

A novel strategy is reported to access high-performance nanozymes via the self-coordination of ferrocyanides ([Fe(CN)6]4-) onto the surface of the Cu3BiS3 (CBS) nanorods. Notably, the in situ formed nanozymes had high catalytic activity, good stability, low cost, and easy mass production. The formed nanozyme catalyzed the oxidation of the typical chromogenic substrate of 3,3',5,5'-tetramethylbenzidine (TMB) with a distinctive absorption peak at 652 nm, accompanied by a blue color development. Moreover, the attachment of deoxyribonucleoside 5'-monophosphates (dNMP) beforehand onto the surface of CBS prevented coordination of ferrocyanides and resulted in the tunable formation of the nanozyme, thereby enabling the construction of an exquisite biosensing platform. Taking the aptasensing of chloramphenicol (CAP) as an example, the engineered nanozyme allowed the construction of a homogenous, label-free, and high-performance bioassay in terms of its convenience and high sensitivity. Under the optimal conditions, changes in the absorption intensity at 652 nm for the oxidized TMB provides a good linear correlation with the logarithm of CAP concentrations in the range 0.1 pM to 100 nM, and the limit of detection was 0.033 pM (calculated from 3σ/s). Considering a vast number of bioreactions can be connected to dNMP production, we expect the engineerable nanozyme as a universal signal transduction scaffold for versatile applications in bioassays. Through the attachment of deoxyribonucleoside 5'-monophosphate (dNMP) on the surface of CBS to regulate the generation of self-coordinated nanozyme CBS/BiHCF, a homogeneous, label-free, and high-performance universal aptasensing platform was constructed.

Invoking Cathodic Photoelectrochemistry through a Spontaneously Coordinated Electron Transporter: A Proof of Concept Toward Signal Transduction for Bioanalysis.

Most of the cathodic photoelectrochemical (PEC) bioassays rely on electron accepting molecules for signal stimuli; unfortunately, the performances of which are still undesirable. New signal transduction strategies are still highly expected for the further development of cathodic photoelectrochemistry as a potentially competitive method. This work represents a new concept of invoked cathodic photoelectrochemistry by a spontaneously formed electron transporter for innovative operation of the sensing strategy. Specifically, the hexacyanoferrate(II) in solution easily self-coordinated with CuO nanomaterials and formed electron transporting copper hexacyanoferrate (CuHCF) on the surface, which endowed improved carrier separation for presenting augmented photocurrent readout. Exemplified by the T4 polynucleotide kinase (T4 PNK) and its inhibitors as targets, a homogenous cathodic PEC biosensing platform was achieved with the distinctive merits of label-free, immobilization-free, and split-mode readout. The mechanism revealed here provided a totally different perspective for signal transduction in cathodic photoelectrochemistry. Hopefully, it may stimulate more interests in the design and construction of semiconductor/transporter counterparts for exquisite operation of photocathodic bioanalysis.

Label-free and highly sensitive detection of DNA adenine methylation methyltransferase through cathodic photoelectrochemistry.

In this work, we report the first exploration of cathodic photoelectrochemistry for the determination of the activity of DNA adenine methylation (Dam) methyltransferase (MTase). In this sensing system, potassium ferricyanide (K3[Fe(CN)6]) can greatly stimulate the photocurrent of a CdS quantum dot (QD) sensitized NiO (NiO/CdS) photocathode. After immobilization of the hairpin DNA probe on the electrode surface, its high steric hindrance and the electrostatic repulsion block the access of K3[Fe(CN)6] to the electrode surface, leading to depressed photocurrent of the photocathode. Once the hairpin DNA probe is methylated by Dam MTase, it can be recognized and cleaved by Dpn I, and then further digested by (Exo I), ultimately leading to the removal of the hairpin DNA probe from the electrode surface. This configurational change induces the decrement of steric hindrance/electrostatic repulsion effects and allows the efficient flux of K3[Fe(CN)6] to the photoelectrode for photocurrent stimulation. The cathodic PEC assay is presented in the "turn-on" mode, which can detect Dam MTase in the linear range from 0.04 to 100 U mL-1, with a detection limit as low as 0.028 U mL-1. In principle, the platform presents a promising method for probing various biomolecules that can lead to configuration or charge variations at the electrode surface, which may become a general strategy for versatile targets.

Intercalated doxorubicin acting as stimulator of PbS photocathode for probing DNA-protein interactions.

Label-free and turn-on DNA-binding protein detection based on the doxorubicin (Dox)-intercalated DNA as a signal stimulator in cathodic photoelectrochemistry is reported. The double-stranded DNA (dsDNA) acted as the matrix accommodating the intercalative Dox and allowed its effective photoelectrochemical (PEC) communication with the PbS quantum dots (QDs) for realizing cathodic photocurrent readout. In the presence of the target of the vascular endothelial growth factor (VEGF), the dsDNA was prevented from being digested by the exonuclease III (Exo III), allowing the anchor of Dox to perform as activation stimuli of the photocurrent. The VEGF can be detected in the linear range from 1.5 pM to 100 nM, with an impressively low detection limit of 0.49 pM. This study hints the prospect of DNA intercalated architectures as innovative signaling transduction elements for wide and versatile cathodic PEC bioassays. Effective signaling molecules that are conducive to probe-related cathodic PEC bioassays using DNA as the recognition or signification elements are scarce but very demanding. Herein, the doxorubicin intercalated in duplex DNA functions as an efficient signal stimulator of PbS-consisted photocathode, and thus hints the versatility of the strategy for various targets through cathodic photoelectrochemistry.

High-throughput photoelectrochemical determination of E. coli O157:H7 by modulation of the anodic photoelectrochemistry of CdS quantum dots via reversible deposition of MnO2.

A method is described for modulating the anodic photoelectrochemistry of netlike CdS quantum dots through the deposition and dissolution of the electron acceptor manganese dioxide (MnO2) on the surface of the photoelectrode. Specifically, the photocurrent of a CdS-modified indium tin oxide (ITO/CdS) electrode is inhibited by chemical deposition of MnO2. However, the photocurrent becomes recovered by oxidative removal of MnO2 with H2O2. This deposition-dissolution reaction modulates the photoelectrochemistry of CdS effectively. A bioassay for Escherichia coli (E. coli) O157:H7 is designed that uses the antimicrobial peptide magainin I as the recognition element. Glucose oxidase (GOx) acts as a catalytic label tracer to produce the signaling molecule H2O2 in the microwell plates. The enzymatically generated H2O2 etches the deposited MnO2 on the photoelectrode and thus enhances the photocurrent. This detection scheme does not cause any damage to biomolecules. It also avoids the adverse effects of immobilized biomolecules for retarding signal production and leads to improved detection when compared to conventional PEC configurations. E. coli can be detected in the 10 to 5.0 × 106 CFU·mL-1 concentration range, and the limit of detection is 3 CFU·mL-1. Graphical abstractSchematic representation of the photoelectrochemical assay of E. coli through the deposition and dissolution of electron accepting manganese dioxide (MnO2) on the surface of the photoelectrode.

Enzyme-Initiated Quinone-Chitosan Conjugation Chemistry: Toward A General in Situ Strategy for High-Throughput Photoelectrochemical Enzymatic Bioanalysis.

Herein we report a general and novel strategy for high-throughput photoelectrochemical (PEC) enzymatic bioanalysis on the basis of enzyme-initiated quinone-chitosan conjugation chemistry (QCCC). Specifically, the strategy was illustrated by using a model quinones-generating oxidase of tyrosinase (Tyr) to catalytically produce 1,2-bezoquinone or its derivative, which can easily and selectively be conjugated onto the surface of the chitosan deposited PbS/NiO/FTO photocathode via the QCCC. Upon illumination, the covalently attached quinones could act as electron acceptors of PbS quantum dots (QDs), improving the photocurrent generation and thus allowing the elegant probing of Tyr activity. Enzyme cascades, such as alkaline phosphatase (ALP)/Tyr and ß-galactosidase (Gal)/Tyr, were further introduced into the system for the successful probing of the corresponding targets. This work features not only the first use of QCCC in PEC bioanalysis but also the separation of enzymatic reaction from the photoelectrode as well as the direct signal recording in a split-type protocol, which enables quite convenient and high-throughput detection as compared to previous formats. More importantly, by using numerous other oxidoreductases that involve quinones as reactants/products, this protocol could serve as a common basis for the development of a new class of QCCC-based PEC enzymatic bioanalysis and further extended for general enzyme-labeled PEC bioanalysis of versatile targets.

In Situ Enzymatically Generated Photoswitchable Oxidase Mimetics and Their Application for Colorimetric Detection of Glucose Oxidase.

In this study, a simple and amplified colorimetric assay is developed for the detection of the enzymatic activity of glucose oxidase (GOx) based on in situ formation of a photoswitchable oxidase mimetic of PO4(3-)-capped CdS quantum dots (QDs). GOx catalyzes the oxidation of 1-thio-ß-d-glucose to give 1-thio-ß-d-gluconic acid which spontaneously hydrolyzes to ß-d-gluconic acid and H2S; the generated H2S instantly reacts with Cd(2+) in the presence of Na3PO4 to give PO4(3-)-stabilized CdS QDs in situ. Under visible-light (λ ≥ 400 nm) stimulation, the PO4(3-)-capped CdS QDs are a new style of oxidase mimic derived by producing some active species, such as h⁺, (•)OH, O2(•-) and a little H2O2, which can oxidize the typical substrate (3,3,5,5-tetramethylbenzydine (TMB)) with a color change. Based on the GOx-triggered growth of the oxidase mimetics of PO4(3-)-capped CdS QDs in situ, we developed a simple and amplified colorimetric assay to probe the enzymatic activity of GOx. The proposed method allowed the detection of the enzymatic activity of GOx over the range from 25 µg/L to 50 mg/L with a low detection limit of 6.6 µg/L. We believe the PO4(3-)-capped CdS QDs generated in situ with photo-stimulated enzyme-mimicking activity may find wide potential applications in biosensors.

The pilot study of radiology nursing intervention in abdominal 3-T Magnetic Resonance examination.

OBJECTIVE: The aim of this study was to investigate the effect of radiology nursing intervention in abdominal examination at 3-T MRI. METHOD: 60 patients with abdominal diseases were divided into two groups randomly: MR nursing intervention group and control group. All the patients underwent abdominal MR examination at 3-T. The MR nursing interventions were performed in nursing intervention group. The outcomes, including one-time success rate, the ratio of diagnosable MR images and the points of image quality, were compared between these two groups. RESULTS: The one-time success rates in control group and MR nursing intervention group were 66.67% and 96.67% with significant difference ( χ2 =9.017, P<0.05). The ratios of diagnosable images in the two groups were 76.67% and 96.67% with significant difference (χ2 =5.192, P<0.05). The points of MR image quality in the two groups were 1.87±0.86 and 2.33±0.55, respectively. There was significant difference between these two groups (t=-2.508, P<0.05). CONCLUSION: The effective nursing intervention can make the patients cooperation better in abdominal MR examination and improve the image quality significantly.

Versatile and Amplified Biosensing through Enzymatic Cascade Reaction by Coupling Alkaline Phosphatase in Situ Generation of Photoresponsive Nanozyme.

The alkaline phosphatase (ALP) biocatalysis followed by the in situ enzymatic generation of a visible light responsive nanozyme is coupled to elucidate a novel amplification strategy by enzymatic cascade reaction for versatile biosensing. The enzymatic hydrolysis of o-phosphonoxyphenol (OPP) to catechol (CA) by ALP is allowed to coordinate on the surface of TiO2 nanoparticles (NPs) due to the specificity and high affinity of enediol ligands to Ti(IV). Upon the stimuli by CA generated from ALP, the inert TiO2 NPs is activated, which demonstrates highly efficient oxidase mimicking activity for catalyzing the oxidation of the typical substrate of 3,3',5,5'-tetramethylbenzidine (TMB) under visible light (λ ≥ 400 nm) irradiation utilizing dissolved oxygen as an electron acceptor. On the basis of the cascade reaction of ALP and the nanozyme of CA coordinated TiO2 (TiO2-CA) NPs, we design exquisitely colorimetric biosensors for probing ALP activity and its inhibitor of 2, 4-dichlorophenoxyacetic acid (2,4-DA). Quantitative probing of ALP activity in a wide linear range from 0.01 to 150 U/L with the detection limit of 0.002 U/L is realized, which endows the methodology with sufficiently high sensitivity for potentially practical applications in real samples of human serum (ALP level of 40-190 U/L for adults). In addition, a novel immunoassay protocol by taking mouse IgG as an example is validated using the ALP/nanozyme cascade amplification reaction as the signal transducer. A low detection limit of 2.0 pg/mL is attained for mouse IgG, which is 4500-fold lower than that of the standard enzyme-linked immuno-sorbent assay (ELISA) kit. Although only mouse IgG is used as a proof-of-concept in our experiment, we believe that this approach is generalizable to be readily extended to other ELISA systems. This methodology opens a new horizon for amplified and versatile biosensing including probing ALP activity and following ALP-based ELISA immunoassays.

Using G-quadruplex/hemin to "switch-on" the cathodic photocurrent of p-type PbS quantum dots: toward a versatile platform for photoelectrochemical aptasensing.

We present a novel photoelectrochemical (PEC) biosensing platform by taking advantage of the phenomenon that hemin intercalated in G-quadruplex "switched-on" the cathode photocurrent of p-type PbS quantum dots (QDs). Photoinduced electron transfer between PbS QDs and G-quadruplex/hemin(III) complexes with the subsequent catalytic oxygen reduction by the reduced G-quadruplex/hemin(II) led to an obvious enhancement in the cathodic photocurrent of the PbS QDs. For the detection process, in the presence of hemin, the specific recognition of the targets with the sensing sequence would trigger the formation of a stable G-quadruplex/hemin complex, which will result in reduced charge recombination and hence amplified photocurrent intensity of the PbS QDs. By using different target sequences, the developed system made possible a novel, label-free "switch-on" PEC aptasensor toward versatile biomolecular targets such as DNA and thrombin. Especially, with ambient oxygen to regenerate G-quadruplex/hemin(II) to G-quadruplex/hemin(III), this substrate-free strategy not only promoted the photoelectric effect and thus the enhanced sensitivity of the system, but also avoided the addition of supplementary substrates of G-quadruplex/hemin such as H2O2 and organic substances.

Combination therapy with pegylated interferon alpha-2b and adefovir dipivoxil in HBeAg-positive chronic hepatitis B versus interferon alone: a prospective, randomized study.

Currently available monotherapies of oral nucleoside/nucleotide analogs or interferon are unable to achieve a sustained and effective response in most of patients with chronic hepatitis B (CHB). The objective of the present study was to compare the efficacy and safety of pegylated interferon (Peg-IFN) alpha-2b plus adefovir dipivoxil combination therapy versus Peg-IFN alpha-2b alone. Sixty-one HBeAg-positive chronic hepatitis B patients were randomized to receive Peg-IFN alpha-2b alone (1.5 µg/kg once weekly) or Peg-IFN alpha-2b plus adefovir (10 mg daily) for up to 52 weeks. Efficacy and safety analyses were performed on all participants who received at least one dose of study medication. The rate of HBeAg seroconversion and undetectable HBV-DNA were evaluated after 52 weeks of therapy. At the end of treatment, 11 of 30 (36.7%) patients receiving combination therapy achieved HBeAg seroconversion versus 8 of 31 (25.8%) in the monotherapy group (P=0.36). In contrast, the percentage of patients with undetectable serum HBV DNA was significantly higher in the combination group than in the monotherapy group (76.7% vs. 29.0%, P<0.001). Thyroid dysfunction was more frequent in the combination group than in the monotherapy group (P<0.05). In HBeAg-positive CHB, combination of Peg-IFN alpha-2b and adefovir for 52 weeks resulted, at the end of treatment, in a higher virological response but without significant impact on the rate of HBeAg seroconversion and possibly an adverse effect on thyroid function.

[Cloning and expression of transferrin protein from Culex pipiens pallens and a study of its antimicrobial activity].

OBJECTIVE: To clone and express transferrin (Tsf) from Culex pipiens pallens in Pichia pastoris, and detect its antibacterial activity. METHODS: The coding region of transferrin from Culex pipiens pallens was amplified by RT-PCR. The product of RT-PCR was inserted into the downstream of gene encoding a-factor signal sequence in a Pichia pastoris secreting expression vector pGAPZalpha-A. The recombinant pGAPZalpha-A-Tsf vector was transformed into P. pastoris GS115 by electroporation. Recombinant strains pGAPZa-A-Tsf/GS115 were screened by Zeocin resistance and PCR. Recombinant protein was detected by SDS-PAGE and Western blotting. The recombinant transferrin protein was purified by using Ni-NTA resin. The antibacterial activity of the purified transferrin against Escherichia coli was detected. RESULTS: The transferrin gene with 2,100 bp was obtained by RT-PCR. The product of recombinant plasmid pGAPZalpha-A-Tsf was approximately 2 127 bp by double digestion with restriction enzymes, consistent with the anticipated fragment length. Sequencing results showed that the inserted sequence was correct. PCR result showed that the recombinant plasmid pGAPZalpha-A-Tsf/GS115 was constructed. The results of SDS-PAGE and Western blotting showed that the relative molecular weight (Mr) of the protein was about 80,200. The recombinant transferrin protein showed antibacterial activity against Escherichia coli, and the minimum concentration was 0.25 mg/ml. CONCLUSION: The recombinant transferrin protein from Culex pipiens pallens has been expressed in P. pastoris, and shows antibacterial activity against E. coli.

Effects of microRNA-21 on the interleukin 12/signal transducer and activator of transcription 4 signaling pathway in asthmatic mice.

OBJECTIVE: To study the effect of microRNA-21 (miRNA-21) on the regulation of the interleukin 12 (IL-12)/signal transducer and activator of transcription 4 (STAT4) pathway in the lung tissue of asthmatic mice. MATERIAL AND METHODS: Forty five male C57BL/6 mice were randomly divided into three groups of 15 mice each: normal control, asthmatic model, and dexamethasone. Our mouse model of allergic asathma was established using OVA sensitization and challenge. Hematoxylin and eosin staining was performed to observe the pathological changes in lung tissue morphology. Both the total cell number and the amount of eosinophils (EOS) in the bronchoalveolar lavage fluid (BALF) were manually counted. The expression of miRNA-21 was detected by real time quantitative PCR. The expression levels of IL-12 and STAT4 in lung tissue were assayed via western blot, and immunohistochemistry was used to observe the distribution of their expression. RESULTS: The expression levels of miRNA-21 as well as the total number of BALF cells and EOS were significantly higher in the asthmatic model group than in the control or dexamethasone groups, with significantly higher amounts found in the dexamethasone group than in the control group. The expression levels of IL-12 and STAT4 proteins were lower in the asthmatic model group than in the control and dexamethasone groups, with a significantly lower expression of IL-12 and STAT4 in the dexamethasone group than in the control group. CONCLUSIONS: The expression level of miRNA-21 was significantly increased and the expression level of IL-12 and STAT4 proteins was significantly decreased in allergic asthmatic mice compared with normal control mice. These findings suggest a role for miRNA-21 and the IL-12/STAT4 pathway in the development of allergic asthma.

Target mediated bioreaction to engineer surface vacancy effect on Bi2O2S nanosheets for photoelectrochemical detection of FEN1.

Photoelectrochemistry represents a promising technique for bioanalysis, though its application for the detection of Flap endonuclease 1 (FEN1) has not been tapped. Herein, this work reports the exploration of creating oxygen vacancies (Ov) in situ onto the surface of Bi2O2S nanosheets via the attachment of dopamine (DA), which underlies a new anodic PEC sensing strategy for FEN1 detection in label-free, immobilization-free and high-throughput modes. In connection to the target-mediated rolling circle amplification (RCA) reaction for modulating the release of the DA aptamer to capture DA, the detection system showed good performance toward FEN1 analysis with a linear detection range of 0.001-10 U/mL and a detection limit of 1.4 × 10-4 U/mL (S/N = 3). This work features the bioreaction engineered surface vacancy effect of Bi2O2S nanosheets as a PEC sensing strategy, which allows a simple, easy to perform, sensitive and selective method for the detection of FEN1. This sensing strategy might have wide applications in versatile bioasssays, considering the diversity of a variety of biological reactions may produce the DA aptamer.

Thioredoxin Reductase-Mediated Reaction Evokes In Situ Surface Polarization Effect on BiOIO3: Toward a New Sensing Strategy for Cathodic Photoelectrochemistry.

We have witnessed the fast progress of cathodic photoelectrochemistry over the past decades, though its signal transduction tactic still lacks diversity. Exploring new sensing strategies for cathodic photoelectrochemistry is extremely demanding yet hugely challenging. This article puts forward a unique idea to incorporate an enzymatic reaction-invoked surface polarization effect (SPE) on the surface of BiOIO3 to implement an innovative cathodic photoelectrochemical (PEC) bioanalysis. Specifically, the thioredoxin reductase (TrxR)-mediated reaction produced the polar glutathione (GSH), which spontaneously coordinated to the surface of BiOIO3 and induced SPE by forming a polarized electric field, resulting in improved electron (e-) and hole (h+) pair separation efficiency and an enhanced photocurrent output. Correlating this phenomenon with the detection of TrxR exhibited a high performance in terms of sensitivity and selectivity, achieving a linear range of 0.007-0.5 µM and a low detection limit of 2.0 nM (S/N = 3). This study brings refreshing inspiration for the cathodic PEC signal transduction tactic through enzyme-mediated in situ reaction to introduce SPE, which enriches the diversity of available signaling molecules. Moreover, this study unveils the potential of in situ generated SPE for extended and futuristic applications.

The Relationship between Quantitative Parameters of Dual-energy CT and HIF-1α Expression in Non-Small Cell Lung Cancer.

OBJECTIVE: This study aimed to investigate whether there is a correlation between quantitative parameters of dual-energy computed tomography (DECT) and the relative expression of HIF-1α in patients with non-small cell lung cancer (NSCLC) to preliminarily explore the value of DECT in evaluating the hypoxia of tumor microenvironment and tumor biological behavior and provide more information for the treatment of NSCLC. METHODS: This retrospective research included 36 patients with pathologically confirmed NSCLC who underwent dual-energy enhanced CT scans. The quantitative parameters of DECT were analyzed, including iodine concentration, water concentration, the CT values corresponding to 40keV, 70keV, 100keV, and 130keV in arterial and venous phases, and the normalized iodine concentration and the slope of the energy spectrum curve were calculated. Postoperative specimens underwent HIF immunohistochemical staining by two pathologists. Spearman correlation analysis was adopted as the statistical methodology. The data were analyzed by SPSS26.0 statistical software. RESULTS: Water concentration (r=0.659, P<0.001 and r= 0.632, P<0.001, the CT values corresponding to 100keV (r=0.645, P<0.001 and r= 0.566, P<0.001) and 130keV (r=0.687, P<0.001 and r= 0.682, P<0.001) in arterial and venous phases, and CT value of 70keV in arterial phase (r=0.457, P=0.005) were positively correlated with HIF-1α expression level. There was no correlation among iodine concentration, standardized iodine concentration, CT value of 40keV, λHU, and HIF-1α expression in arterial and venous levels (P >0.05). CONCLUSION: The quantitative parameters of DECT have a certain correlation with HIF-1α expression in NSCLC. Moreover, it has been demonstrated that DECT can be used to predict hypoxia in tumor tissues and the prognosis of lung cancer patients.

Olivibacter jilunii sp. nov., isolated from DDT-contaminated soil.

Bacterial strain 14-2A(T), isolated from a long-term DDT-contaminated soil in China, was characterized by using a polyphasic approach to clarify its taxonomic position. Strain 14-2A(T) was found to be Gram-negative, aerobic, non-spore-forming, non-motile, non-flagellated and rod-shaped. The new isolate was able to grow at 4-42 °C, pH 6.0-9.0 and with 0-5 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the family Sphingobacteriaceae. The 16S rRNA gene sequence of strain 14-2A(T) showed the highest similarity with Olivibacter oleidegradans TBF2/20.2(T) (99.4 %), followed by Pseudosphingobacterium domesticum DC-186(T) (93.8 %), Olivibacter ginsengisoli Gsoil 060(T) (93.6 %), Olivibacter terrae Jip13(T) (93.1 %), Olivibacter soli Gsoil 034(T) (92.8 %) and Olivibacter sitiensis AW-6(T) (89.6 %). The DNA-DNA hybridization value between strains 14-2A(T) and O. oleidegradans TBF2/20.2(T) was 34.45±2.11 %. Strain 14-2A(T) contained phosphatidylethanolamine, phosphatidylmonomethylethanolamine, aminophospholipid and phosphatidylinositol mannoside as the major polar lipids. The DNA G+C content was 41.2 mol%. MK-7 is the major isoprenoid quinone. Summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 and iso-C17 : 0 3-OH are the major fatty acids. The phenotypic and chemotaxonomic data confirmed the affiliation of strain 14-2A(T) to the genus Olivibacter. On the basis of the phylogenetic and phenotypic characteristics, and chemotaxonomic data, strain 14-2A(T) is considered to represent a novel species of the genus Olivibacter, for which the name Olivibacter jilunii sp. nov. is proposed; the type strain is 14-2A(T) ( = KCTC 23098(T) = CCTCC AB 2010105(T)).

Novel switchable sensor for phosphate based on the distance-dependant fluorescence coupling of cysteine-capped cadmium sulfide quantum dots and silver nanoparticles.

A novel switchable sensor was developed for the determination of phosphate based on Ce(3+) induced aggregation and phosphate triggered disaggregation of cysteine (Cys)-capped CdS quantum dots (QDs) and silver nanoparticles (AgNPs). The rare earth metal Ce(3+) could aggregate a mixture of QDs and AgNPs, which induced electron or energy transfer between CdS QDs and AgNPs and serious fluorescence quenching. However, phosphate dissociated the formed aggregation of CdS QDs and AgNPs, restoring the enhanced fluorescence of Cys-capped CdS triggered by AgNPs. Although, CdS QDs alone could also be used to detect phosphate through the aggregation-disaggregation mechanism adjusted by Ce(3+) and phosphate. It was found that the distance-dependent interaction between AgNPs and CdS QDs driven by Ce(3+) and phosphate could lead to enhanced quenching or enhancement of the fluorescence of Cys-capped CdS to form a more sensitive detection system for phosphate. The developed method was applied in the detection of phosphate in real water samples with acceptable and satisfactory results.