Diastereo-divergent synthesis of chiral hindered ethers via a synergistic calcium(II)/gold(I) catalyzed cascade hydration/1,4-addition reaction

Hindered ethers are ubiquitous in natural products and bioactive molecules. However, developing an efficient method for the stereocontrolled synthesis of all stereoisomers of chiral hindered ethers is highly desirable but challenging. Here we show a strategy that utilizes in situ-generated water as a nucleophile in an asymmetric cascade reaction involving two highly reactive intermediates, 3-furyl methyl cations and ortho-quinone methides (o-QMs), to synthesize chiral hindered ethers. The Ca(II)/Au(I) synergistic catalytic system enables the control of diastereoselectivity and enantioselectivity by selecting suitable chiral phosphine ligands in this cascade hydration/1,4-addition reaction, affording all four stereoisomers of a diverse range of chiral tetra-aryl substituted ethers with high diastereoselectivities (up to >20/1) and enantioselectivities (up to 95% ee). This work provides an example of chiral Ca(II)/Au(I) bimetallic catalytic system controlling two stereogenic centers via a cascade reaction in a single operation.

[Clinical characteristics of 11 patients with Vibrio vulnificus infection and the establishment of a rapid diagnosis procedure for this disease]

Objective: To analyze the clinical characteristics of patients with Vibrio vulnificus infection, share diagnosis and treatment experience, and establish a rapid diagnosis procedure for this disease. Methods: This study was a retrospective case series study. From January 2009 to November 2022, 11 patients with Vibrio vulnificus infection who met the inclusion criteria were admitted to the Department of Burns and Wound Repair of Guangdong Provincial People's Hospital Affiliated to Southern Medical University. The gender, age, time of onset of illness, time of admission, time of diagnosis, route of infection, underlying diseases, affected limbs, clinical manifestations and signs on admission, white blood cell count, hemoglobin, platelet count, C-reactive protein (CRP), alanine transaminase (ALT), aspartate transaminase (AST), creatinine, procalcitonin, albumin, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and blood sodium levels on admission, culture results and metagenomic next-generation sequencing (mNGS) results of pathogenic bacteria and the Vibrio vulnificus drug susceptibility test results during hospitalization, treatment methods, length of hospital stay, and outcomes of all patients were recorded. Comparative analysis was conducted on the admission time and diagnosis time of patients with and without a history of exposure to seawater/marine products, as well as the fatality ratio and amputation of limbs/digits ratio of patients with and without early adequate antibiotic treatment. For the survived patients with hand involvement, the hand function was assessed using Brunnstrom staging at the last follow-up. Based on patients' clinical characteristics and treatment conditions, a rapid diagnosis procedure for Vibrio vulnificus infection was established. Results: There were 7 males and 4 females among the patients, aged (56±17) years. Most of the patients developed symptoms in summer and autumn. The admission time was 3.00 (1.00, 4.00) d after the onset of illness, and the diagnosis time was 4.00 (2.00, 8.00) d after the onset of illness. There were 7 and 4 patients with and without a history of contact with seawater/marine products, respectively, and the admission time of these two types of patients was similar (P>0.05). The diagnosis time of patients with a history of contact with seawater/marine products was 2.00 (2.00, 5.00) d after the onset of illness, which was significantly shorter than 9.00 (4.25, 13.00) d after the onset of illness for patients without a history of contact with seawater/marine products (Z=-2.01, P<0.05). Totally 10 patients had underlying diseases. The affected limbs were right-hand in 8 cases, left-hand in 1 case, and lower limb in 2 cases. On admission, a total of 9 patients had fever; 11 patients had pain at the infected site, and redness and swelling of the affected limb, and 9 patients each had ecchymosis/necrosis and blisters/blood blisters; 6 patients suffered from shock, and 2 patients developed multiple organ dysfunction syndrome. On admission, there were 8 patients with abnormal white blood cell count, hemoglobin, and albumin levels, 10 patients with abnormal CRP, procalcitonin, and NT-proBNP levels, 5 patients with abnormal creatinine and blood sodium levels, and fewer patients with abnormal platelet count, ALT, and AST levels. During hospitalization, 4 of the 11 wound tissue/exudation samples had positive pathogenic bacterial culture results, and the result reporting time was 5.00 (5.00, 5.00) d; 4 of the 9 blood specimens had positive pathogenic bacterial culture results, and the result reporting time was 3.50 (1.25, 5.00) d; the mNGS results of 7 wound tissue/exudation or blood samples were all positive, and the result reporting time was 1.00 (1.00, 2.00) d. The three strains of Vibrio vulnificus detected were sensitive to 10 commonly used clinical antibiotics, including ciprofloxacin, levofloxacin, and amikacin, etc. A total of 10 patients received surgical treatment, 4 of whom had amputation of limbs/digits; all patients received anti-infection treatment. The length of hospital stay of 11 patients was (26±11) d, of whom 9 patients were cured and 2 patients died. Compared with that of the 6 patients who did not receive early adequate antibiotic treatment, the 5 patients who received early adequate antibiotic treatment had no significant changes in the fatality ratio or amputation of limbs/digits ratio (P>0.05). In 3 months to 2 years after surgery, the hand function of 8 patients was assessed, with results showing 4 cases of disabled hands, 2 cases of incompletely disabled hands, and 2 cases of recovered hands. When a patient had clinical symptoms of limb redness and swelling and a history of contact with seawater/marine products or a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection. Conclusions: Vibrio vulnificus infection occurs most frequently in summer and autumn, with clinical manifestations and laboratory test results showing obvious infection characteristics, and may be accompanied by damage to multiple organ functions. Both the fatality and disability ratios are high and have a great impact on the function of the affected limbs. Early diagnosis is difficult and treatment is easily delayed, but mNGS could facilitate rapid detection. For patients with red and swollen limbs accompanied by a history of contact with seawater/marine products or with a pre-examination triage RiCH score of Vibrio vulnificus sepsis ≥1, the etiological testing should be initiated immediately to quickly diagnose Vibrio vulnificus infection.

Quantum Mechanical/Molecular Mechanical Elucidation of the Catalytic Mechanism of Leukotriene A4 Hydrolase as an Epoxidase

Leukotriene A4 hydrolase (LTA4H) functions as a mono-zinc bifunctional enzyme with aminopeptidase and epoxidase activities. While the aminopeptidase mechanism is well understood, the epoxidase mechanism remains less clear. In continuation of our prior research, we undertook an in-depth exploration of the LTA4H catalytic role as an epoxidase, employing a combined SCC-DFTB/CHARMM method. In the current work, we found that the conversion of LTA4 to leukotriene B4 (LTB4) involves three successive steps: epoxy ring opening (RO), nucleophilic attack (NA), and proton transfer (PT) reactions at the epoxy oxygen atom. Among these steps, the RO and NA stages constitute the potential rate-limiting step within the entire epoxidase mechanism. Notably, the NA step implicates D375 as the general base catalyst, while the PT step engages protonated E271 as the general acid catalyst. Additionally, we delved into the mechanism behind the formation of the isomer product, Δ6-trans-Δ8-cis-LTB4. Our findings debunked the feasibility of a direct LTB4 to iso-LTB4 conversion. Instead, we highlight the possibility of isomerization from LTA4 to its isomeric conjugate (iso-LTA4), showing comparable energy barriers of 5.1 and 5.5 kcal/mol in aqueous and enzymatic environments, respectively. The ensuing dynamics of iso-LTA4 hydrolysis subsequently yield iso-LTB4 via a mechanism akin to LTA4 hydrolysis, albeit with a heightened barrier. Our computations firmly support the notion that substrate isomerization exclusively takes place prior to or during the initial substrate-binding phase, while LTA4 remains the dominant conformer. Notably, our simulations suggest that irrespective of the active site's constrained L-shape, isomerization from LTA4 to its isomeric conjugate remains plausible. The mechanistic insights garnered from our simulations furnish a valuable understanding of LTA4H's role as an epoxidase, thereby facilitating potential advancements in inhibitor design.

Selective modulation of alkali metal ions on acetylcholinesterase

Acetylcholinesterase (AChE) is an important hydrolase in cholinergic synapses and a candidate target in the treatment of Alzheimer's disease. The lithium treatment widely used in neurological disorders can alter the AChE activity, yet the underlying mechanism of how the ion species regulate the enzymatic activity remains unclear. In this work, we performed combined quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) simulations and well-tempered metadynamics to understand the modulation of human AChE (hAChE) activity using three alkali metal ions (Li+, Na+, and K+) in different concentrations. Our simulations show that the binding affinity and catalytic activity are affected by different ion species through allosteric ion coordination geometries on the hAChE complex and distant electrostatic screening effect. A Li+ cluster involving D330, E393, and D397 residues and three Li+ ions was found to be highly conserved and can be critical to the enzyme activity. Binding energy calculations indicate that the electrostatic screening from allosterically bound cations can affect the key residues at the catalytic site and active-site gorge, including E199. Furthermore, an increase in ion concentration can lead to lower reactivity, especially for Li+ ions, which exhibit more cation-hAChE contacts than Na+ and K+. The selective ion binding and their preferred modulation on hAChE are highly related to ion species. This work provides a molecular perspective on selective modulation by different ion species of the enzyme catalytic processes.

Development and Validation of a Nomogram for Patients with Lung Large Cell Neuroendocrine Carcinoma

PURPOSE/OBJECTIVE(S)

Pulmonary large cell neuroendocrine carcinoma (LCNEC) is a rarely high-grade neuroendocrine carcinoma of the lung with features of both small cell and non-small cell lung cancer. We aim to construct a prognostic nomogram combined with the clinical features and treatment options to predict disease-specific survival (DSS), meanwhile, evaluating the role of prophylactic cranial irradiation (PCI) in LCNEC by subgroup analysis.

MATERIALS/METHODS

A total of 713 patients diagnosed with LCNEC from the US National Cancer Institute's Surveillance Epidemiology and End Results (SEER) registry between 2010 and 2016. Cox proportional hazards analysis was conducted to choose the significant predictors of DSS. External validation was performed using 77 patients with LCNEC in the West China Hospital Sichuan University between 2010 and 2018, subgroup analysis was carried out for the whole brain radiotherapy (WBRT) and PCI population. The predictive accuracy and discriminative capability were estimated by the concordance index (C-index), calibration curve and receiver operating characteristic (ROC) curve. The clinical applicability of the nomogram was verified through the decision curve analysis (DCA).

RESULTS

Six independent risk factors for DSS were identified and integrated into the nomogram. The nomogram achieved good C- indexes of 0.803 and 0.767 in the training and validation group respectively. Moreover, the calibration curves of both cohorts for the probability of survival showed good agreement between prediction by nomogram and actual observation in 1-, 3- and 5-year DSS. The ROC curves demonstrated the prediction accuracy of the established nomogram (all AUC>0.8). DCA confirmed the better potential clinical practicality of the nomogram in the prediction of LCNEC survival than AJCC staging. A risk classification system was built which could perfectly classify LCNEC patients into high- and low-risk groups(p<0.001). Subgroup analysis showed that WBRT did not bring survival benefits, PCI appeared to have survival benefits in LCNEC patients without brain metastases (p>0.05).

CONCLUSION

The prognostic nomogram developed in this study has certain prognostic value and clinical practicality for LCNEC patients. PCI might be investigated as a means of improving prognosis.

The Positive Effect of Perceived Exercise Benefit and the Negative Effect of Perceived Severity of Disease and Weakness on College Students' Amount of Exercise: The Mediate and Suppressor Role of Physical Fitness Evaluation Self-Efficacy

Background: The decline in the physical fitness of college students has become a serious social problem worldwide. Therefore, exploring the factors affecting the amount of exercise of college students is of great significance in improving college students' physique. According to the expectation value theory and previous studies, perceived exercise benefit and perceived severity of disease and weakness may have positive or negative impact on exercise behavior, and according to the self-efficacy theory, physical evaluation self-efficacy may be the most powerful motivational factors and it play a mediating role between other factors and exercise behavior. Therefore, this study was designed to determine the critical role of physical evaluation self-efficacy in the path of perceived exercise benefit and perceived severity of disease and weakness affecting the amount of exercise of college students.

Methods: By means of Physical Fitness Health Belief of College Students Scale and Physical Activity Rating Scale (PARS-3), 801 undergraduate students were investigated in this study.

Results: (1) When perceived exercise benefit, exercise self-efficacy, and severity of perceived disease and weakness predicted the amount of exercise separately, the first two have a positive effect on the amount of exercise, but the latter has no effect. However, when these three factors entered the regression equation at the same time, the perceived severity of disease and weakness had a negative effect on the amount of exercise. (2) The influence of physical evaluation self-efficacy on the college students' the amount of exercise was bigger than benefit of perceived exercise and the perceived severity of disease and weakness in both separated and simultaneous comparison conditions. (3) Physical evaluation self-efficacy completely mediated the positive effect of perceived exercise benefits on the amount of exercise and inhibited the negative effect of perceived severity of disease and weakness on the amount of exercise.

Conclusion: Physical evaluation self-efficacy has a strong predictive power on the amount of exercise of college students. This was reflected in its ability to mediate the impact of expectation of exercise results and in its ability to suppress the adverse effects of concern about illness on exercise.

Familial left cervical neurofibromatosis 1 with scoliosis: A case report

BACKGROUND

Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder affecting many parts of the body with café au lait spots, skeletal deformity, and scoliosis. A familial case of NF1 with scoliosis and a painless mass had not yet been reported.

CASE SUMMARY

We describe the case of a 15-year-old male patient with a painless lump on the left side of his neck for 10 years and scoliosis. His right shoulder was about 5 cm lower than the left, the left side of his face was deformed, and the left submandibular skin was relaxed. The folding and drooping were obvious and movement was poor. Computed tomography revealed the involvement of the neck, upper chest wall, and surrounding left shoulder, accompanied by bone changes and scoliosis. Histological evaluation showed subepidermal pale blue mucoid degeneration, fibrous fusiform cells in the dermis in a fascicular, woven arrangement. His mother had the same medical history. The diagnosis was neurofibromatosis of the left neck. Various parts of the tumor tissue were serially resected during several visits. Eight months after surgery, there was a slight tendency to regrow.

CONCLUSION

This case of slow-progressing NF1 highlights the importance of early diagnosis and treatment to reduce its impact on the patient’s growth and development.

High-Efficiency Arbitrary Quantum Operation on a High-Dimensional Quantum System

The ability to manipulate quantum systems lies at the heart of the development of quantum technology. The ultimate goal of quantum control is to realize arbitrary quantum operations (AQUOs) for all possible open quantum system dynamics. However, the demanding extra physical resources impose great obstacles. Here, we experimentally demonstrate a universal approach of AQUO on a photonic qudit with the minimum physical resource of a two-level ancilla and a log_{2}d-scale circuit depth for a d-dimensional system. The AQUO is then applied in a quantum trajectory simulation for quantum subspace stabilization and quantum Zeno dynamics, as well as incoherent manipulation and generalized measurements of the qudit. Therefore, the demonstrated AQUO for complete quantum control would play an indispensable role in quantum information science.

Induction and Monitoring of DNA Phase Separation in Living Cells by a Light-Switching Ruthenium Complex

Phase separation of DNA is involved in chromatin packing for the regulation of gene transcription. Visualization and manipulation of DNA phase separation in living cells present great challenges. Herein, we present a Ru(II) complex (Ru1) with high DNA binding affinity and DNA "light-switch" behavior that can induce and monitor DNA phase separation both in vitro and in living cells. Molecular dynamics simulations indicate that the two phen-PPh₃ ligands with positively charged lipophilic triphenylphosphine substituents and flexible long alkyl chains in Ru1 play essential roles in the formation of multivalent binding forces between DNA molecules to induce DNA phase separation. Importantly, the unique environmental sensitive emission property of Ru1 enables direct visualization of the dynamic process of DNA phase separation in living cells by two-photon phosphorescent lifetime imaging. Moreover, Ru1 can change the gene expression pattern by modulating chromatin accessibility as demonstrated by integrating RNA-sequencing and transposase-accessible chromatin with high-throughput sequencing. In all, we present here the first small-molecule-based tracer and modulator of DNA phase separation in living cells and elucidate its impact on the chromatin state and transcriptome.

Experimental Simulation of Open Quantum System Dynamics via Trotterization

Digital quantum simulators provide a diversified tool for solving the evolution of quantum systems with complicated Hamiltonians and hold great potential for a wide range of applications. Although much attention is paid to the unitary evolution of closed quantum systems, dissipation and noise are vital in understanding the dynamics of practical quantum systems. In this work, we experimentally demonstrate a digital simulation of an open quantum system in a controllable Markovian environment with the assistance of a single ancillary qubit. By Trotterizing the quantum Liouvillians, the continuous evolution of an open quantum system is effectively realized, and its application in error mitigation is demonstrated by adjusting the simulated noise intensities. High-order Trotter for open quantum dynamics is also experimentally investigated and shows higher accuracy. Our results represent a significant step toward hardware-efficient simulation of open quantum systems and error mitigation in quantum algorithms in noisy intermediate-scale quantum systems.

Manipulating Complex Hybrid Entanglement and Testing Multipartite Bell Inequalities in a Superconducting Circuit

Quantum correlations in observables of multiple systems not only are of fundamental interest, but also play a key role in quantum information processing. As a signature of these correlations, the violation of Bell inequalities has not been demonstrated with multipartite hybrid entanglement involving both continuous and discrete variables. Here we create a five-partite entangled state with three superconducting transmon qubits and two photonic qubits, each encoded in the mesoscopic field of a microwave cavity. We reveal the quantum correlations among these distinct elements by joint Wigner tomography of the two cavity fields conditional on the detection of the qubits and by test of a five-partite Bell inequality. The measured Bell signal is 8.381±0.038, surpassing the bound of 8 for a four-partite entanglement imposed by quantum correlations by 10 standard deviations, demonstrating the genuine five-partite entanglement in a hybrid quantum system.

High glucose promotes prostate cancer cells apoptosis via Nrf2/ARE signaling pathway

OBJECTIVE

To explore the influences of high glucose on the proliferation and apoptosis of prostate cancer cells and analyze its possible mechanism of action.

MATERIALS AND METHODS

Human prostate cancer cell line LNCaP was divided into control group, mannitol group, and high glucose group. Then, the proliferation in each group was detected via methyl-thiazolyl-tetrazolium (MTT) assay. Hoechst staining assay was performed to determine the apoptosis level in each group. Western blotting was employed to measure the expression levels of apoptosis-related proteins and nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and γ-glutamylcysteine synthetase (γ-GCS) proteins. The cellular reactive oxygen species (ROS) level was measured through 2,7-dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. Enzyme-linked immunosorbent assay (ELISA) was carried out to detect the content of lactate dehydrogenase (LDH) and inflammatory factors.

RESULTS

High glucose significantly promoted the proliferation of prostate cancer cells LNCaP (p<0.01) and increased the apoptosis level of cells (p<0.01). In high glucose group, the expression level of Caspase-3 protein was overtly increased (p<0.01), while that of B-cell lymphoma-2 (Bcl-2)/Bcl-2 associated X protein (Bax) was significantly decreased (p<0.01). High glucose group had clearly increased the content of ROS (p<0.01), LDH (p<0.01), and interleukin-6 (IL-6) (p<0.01), but decreased the content of IL-10 (p<0.01). High glucose notably lowered the protein expression levels of Nrf2, HO-1, and γ-GCS in the cells (p<0.01).

CONCLUSIONS

High glucose represses the activation of the Nrf2/anti-oxidation response element (ARE) signaling pathway in prostate cancer cells and increases the content of ROS, IL-6, and the expression of apoptotic proteins in the cells, thus promoting the apoptosis of prostate cancer cells.

Targeted regulation of miR-195 on MAP2K1 for suppressing ADM drug resistance in prostate cancer cells

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "Targeted regulation of miR-195 on MAP2K1 for suppressing ADM drug resistance in prostate cancer cells, by J.-Y. Zhang, Y.-N. Li, X. Mu, Z.-L. Pan, W.-B. Liu, published in Eur Rev Med Pharmacol Sci 2018; 22 (24): 8599-8608-DOI: 10.26355/eurrev_201812_16623-PMID: 30575899" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/16623.

Demonstration of Controlled-Phase Gates between Two Error-Correctable Photonic Qubits

To realize fault-tolerant quantum computing, it is necessary to store quantum information in logical qubits with error correction functions, realized by distributing a logical state among multiple physical qubits or by encoding it in the Hilbert space of a high-dimensional system. Quantum gate operations between these error-correctable logical qubits, which are essential for implementation of any practical quantum computational task, have not been experimentally demonstrated yet. Here we demonstrate a geometric method for realizing controlled-phase gates between two logical qubits encoded in photonic fields stored in cavities. The gates are realized by dispersively coupling an ancillary superconducting qubit to these cavities and driving it to make a cyclic evolution depending on the joint photonic state of the cavities, which produces a conditional geometric phase. We first realize phase gates for photonic qubits with the logical basis states encoded in two quasiorthogonal coherent states, which have important implications for continuous-variable-based quantum computation. Then we use this geometric method to implement a controlled-phase gate between two binomially encoded logical qubits, which have an error-correctable function.

QM/MM investigation of substrate binding of subclass B3 metallo-β-lactamase SMB-1 from Serratia marcescents: insights into catalytic mechanism

Metallo-β-lactamases (MβLs) can hydrolyze and deactivate lactam-containing antibiotics, which are the major mechanism to cause drug resistance in the treatment of bacterial infections. This has become a global concern due to the lack of clinically approved inhibitors so far. SMB-1 from Serratia marcescents is a novel B3 subclass MβL, which could inactivate nearly all β-lactam-containing antibiotics, e.g., cephalosporins and carbapenems. It represents a new round of worrisome bacterial resistance. In this work, the Michaelis model of SMB-1 in complex with ampicillin was simulated using combined quantum mechanical and molecular mechanical method. Similar with other dizinc MβLs, a Zn-bridged hydroxide ion was simulated as the nucleophile for the hydrolysis reaction assisted by D120. The protonation of D120 could lead to the loss of O_δ2-Zn2 coordination bond, whereas the C3 carboxylate group moves down to become a new ligand to Zn2. The initial β-lactam ring-opening reaction leads to a conserved nitrogen anionic intermediate, which forms a new ligation between the resulted nitrogen anion and Zn2. The corresponding reaction free energy barrier for the first step of lactam ring-opening reaction was calculated to be 19.2 kcal/mol. During the reaction, Q157 serves as the putative "oxyanion hole" rather than Zn1 in L1 enzyme, which was confirmed via the site-directed mutagenesis simulation of Q157A. Our theoretical studies showed some insights into the substrate binding and catalytic mechanism of the SMB-1 metallo-β-lactamase.

Targeted regulation of miR-195 on MAP2K1 for suppressing ADM drug resistance in prostate cancer cells

OBJECTIVE

Extra-cellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway participates in cell proliferation, cycle and apoptosis. MAPK kinase 1 (MAP2K1) activates the ERK/MAPK pathway. The down-regulation of miR-195 is correlated with the onset and drug resistance of prostate cancer. Bioinformatics analysis identified complementary binding sites between miR-195 and MAP2K1. This study aimed to investigate the effect of miR-195 on the proliferation, apoptosis and adriamycin (ADM) resistance of prostate cancer cells.

MATERIALS AND METHODS

Dual-Luciferase reporter gene assay confirmed targeted regulation between miR-195 and MAP2K1. ADM resistant cell line DU145/ADM and PC-3/ADM were generated for comparing the miR-195 and MAP2K1 expression. Apoptosis was measured by flow cytometry and caspase-3 activity was quantified. Cultured cells were treated with miR-195 mimic, followed by quantitative real-time PCR (qRT-PCR) was used for MAP2K1 expression. Western blot measured MAP2K1, ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) expression, and flow cytometry quantified cell apoptosis, followed by EdU staining for cell proliferation.

RESULTS

Targeted regulation existed between miR-195 and MAP2K1 mRNA. Drug-resistant cells had lower miR-195 than parental cells, whilst MAP2K1 expression was higher. Under ADM treatment with IC50 concentration, drug resistant cells showed lower apoptosis. The transfection of miR-195 decreased MAP2K1 expression and p-ERK1/2, elevated cell apoptosis and suppressed EdU positive rate or cell proliferation.

CONCLUSIONS

The down-regulation of miR-195 is correlated with ADM resistance of prostate cancer cells. The over-expression of miR-195 weakens cancer cell proliferation, facilitates cell apoptosis and decreases ADM resistance via targeted inhibition on MAP2K1 expression and ERK/MAPK signal pathway.

P924Prognostic significance of moderate primary mitral regurgitation and atrial fibrillation

Background

Severe primary mitral regurgitation [degenerativeMR (DMR)] is associated with poor outcome, including cardiac death and admission due to worsening heart failure. Whereas little information is available regarding the characteristics of moderate DMR and their impact on prognostic outcome.

The aim of the present study was to investigate the prognosis and its determinant in patients with moderate DMR.

Methods

From 13,700 consecutive patients who underwent transthoracic echocardiography. We selected moderate DMR but without other underlying cardiac diseases. Characteristics and event free rate as compared with age- and gender-matched patients with none to mild MR.

Results

Of a total of our cohort, 185 (1%) patients had moderate DMR, and we compared with 185 age- and gender-matched patients with none to mild MR. During the follow-up period of 1372±655 days, 30 patients (8%) met the composite endpoint defined as cardiac death and admission due to worsening heart failure. Kaplan-Meier analysis showed patients with moderate DMR was significantly associated with a poor outcome compared to patients with none to mild MR (log-ranktest P<0.0001). Cox proportional hazard ratio revealed thatmoderate MR and atrial fibrillation (AF) were the independent predictors of the composite endpoint.

Prgnostic outcome: AF and moderate DMR

Conclusions

Patients withmoderate DMR and concomitant AF had a significant poor outcome. An activesurveillance and some intervention for AF and moderate MR may be required.

Utility of arterial spin labelling MRI for discriminating atypical high-grade glioma from primary central nervous system lymphoma

AIM

To evaluate the ability of arterial spin labelling (ASL) magnetic resonance imaging (MRI) in differentiating primary central nervous system lymphoma (PCNSL) from atypical high-grade glioma (HGG), as well as exploring the underlying pathological mechanisms.

METHODS AND MATERIALS

Twenty-three patients with PCNSL and 17 patients with atypical HGG who underwent ASL-MRI were identified retrospectively. Absolute cerebral blood flow (aCBF) and normalised cerebral blood flow (nCBF) values were obtained, and were compared between PCNSL and atypical HGG using the Mann-Whitney U-test. The performance in discriminating between PCNSL and atypical HGG was evaluated using receiver-operating characteristics analysis and area-under-the-curve (AUC) values for aCBF and nCBF. The correlation between microvessel density (MVD) and aCBF was determined by Spearman's correlation analysis.

RESULTS

Atypical HGG demonstrated significantly higher aCBF, nCBF, and MVD values than PCNSL (p<0.05). The diagnostic accuracy of discriminating PCNSL from atypical HGG showed AUC=0.877 (95% confidence interval [CI] 0.735-0.959) for aCBF, and AUC=0.836 (95% confidence interval [CI] 0.685-0.934) for nCBF. There was a moderate positive correlation between aCBF values of region of interest (ROI >30 mm²) in the enhanced area and MVD values (rho=0.579, p=0.0001), and a strong positive correlation between aCBF values MVD based on "point-to-point biopsy" (rho=0.83, p=0.0029). Interobserver agreements for aCBF and nCBF were excellent (ICC >0.75).

CONCLUSIONS

ASL perfusion MRI is a useful imaging technique for the discrimination between atypical HGG and PCNSL, which may be determined by the difference of MVD between them.

Single-Loop Realization of Arbitrary Nonadiabatic Holonomic Single-Qubit Quantum Gates in a Superconducting Circuit

Geometric phases are noise resilient, and thus provide a robust way towards high-fidelity quantum manipulation. Here we experimentally demonstrate arbitrary nonadiabatic holonomic single-qubit quantum gates for both a superconducting transmon qubit and a microwave cavity in a single-loop way. In both cases, an auxiliary state is utilized, and two resonant microwave drives are simultaneously applied with well-controlled but varying amplitudes and phases for the arbitrariness of the gate. The resulting gates on the transmon qubit achieve a fidelity of 0.996 characterized by randomized benchmarking and the ones on the cavity show an averaged fidelity of 0.978 based on a full quantum process tomography. In principle, a nontrivial two-qubit holonomic gate between the qubit and the cavity can also be realized based on our presented experimental scheme. Our experiment thus paves the way towards practical nonadiabatic holonomic quantum manipulation with both qubits and cavities in a superconducting circuit.

QM/MM Molecular Dynamics Investigations of the Substrate Binding of Leucotriene A4 Hydrolase: Implication for the Catalytic Mechanism

LTA4H is a monozinc bifunctional enzyme which exhibits both aminopeptidase and epoxide hydrolase activities. Its dual functions in anti- and pro-inflammatory roles have attracted wide attention to the inhibitor design. In this work, we tried to construct Michaelis complexes of LTA4H with both a native peptide substrate and LTA4 molecule using combined quantum mechanics and molecular mechanics molecular dynamics simulations. First of all, the zinc ion is coordinated by H295, H299, and E318. For its aminopeptidase activity, similar to conventional peptidases, the fourth ligand to the zinc ion is suggested to be an active site water, which is further hydrogen bonded with a downstream glutamic acid, E296. For the epoxide hydrolase activity, the fourth ligand to the zinc ion is found to be an epoxy oxygen atom. The potential of mean force calculation indicates about an 8.5 kcal/mol activation barrier height for the ring-opening reaction, which will generate a metastable carbenium intermediate. Subsequent frontier molecular orbital analyses suggest that the next step would be the nucleophilic attacking reaction at the C12 atom by a water molecule activated by D375. Our simulations also analyzed functions of several important residues like R563, K565, E271, Y383, and Y378 in the binding of peptide and LTA4.

High Expression of Nuclear Factor of Activated T Cells in Chinese Primary Non-Small Cell Lung Cancer Tissues

Purpose

Nuclear factor of activated T cells (NFAT) has been reported to be involved in the development of various types of cancer including adenocarcinoma of the breast. This research was the first to investigate NFAT protein expression in primary non-small cell lung cancer (NSCLC) tissues from Chinese patients.

Methods

NFAT protein expression was determined in 130 surgically resected primary NSCLC and matched normal tissues by immunohistochemical analysis. The association between NFAT expression and clinical categorical variables was further analyzed with the SPSS software.

Results

We found that NFAT expression was much higher in 85 tumor tissues (65.4%) and lower in 45 tumor tissues (34.6%) compared with the matched normal tissues. Further statistical analysis by the chi-square test showed that high expression of NFAT proteins was significantly associated with tumor differentiation (p=0.045), invasion (p=0.031), histology (p<0.0001), tumor size (p=0.038) and cigarette smoking history (p=0.024). However, there was no correlation between the expression of NFAT proteins and pTNM classification, and no difference in 5-year survival rate between patients with high or low expression of NFAT proteins. Multivariate logistic regression analysis for the correlation between NFAT protein expression levels and various characteristics showed a significant association with histology (p=0.008, OR=0.273).

Conclusion

Our results revealed that high NFAT expression was present in Chinese NSCLCs and that NFAT expression might be involved in the process of human lung cancer development.

An Outbreak of Surgical Site Infections in A Neurosurgical Ward

Objective To survey an outbreak of surgical site infections in a neurosurgery ward of a tertiary hospital. Methods The patients of surgical site infection were investigated individually based on a uniformly designed epidemiological survey form. The distribution of cases was analyzed by characteristic epidemiology,and a case-control study was carried to explore the risk factors. Results A total of 9 patients with surgical site infections from February 5 to March 7,2014 were identified in 68 patients who had received surgery in a neurosurgery ward,yielding a prevalence of 13.24%. The infections occurred in 7 of 14 patients who had used surgicel,a hemostatic agent,and in 2 of 54 patients who had not used surgicel. (χ²=16.637,P<0.001). Conclusion The use of surgicel may be the cause of this surgical site infection outbreak.

Evaluation of ompA and pgtE genes in determining pathogenicity in Salmonella enterica serovar Enteritidis

Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis) is a major causative agent of gastroenteritis in humans. This important food-borne pathogen also colonises the intestinal tracts of poultry and can spread systemically, especially in chickens. To identify the S. Enteritidis virulence genes involved in infection and colonisation of chickens, chromosomal deletion mutants of the ompA and pgtE genes, which encode essential components of omptins, were constructed. There were no significant differences between the wild-type and ompA and pgtE mutants in a series of in vitro assays, including an intracellular survival assay, survival in specific-pathogen-free (SPF) chicken serum, and in vitro competition assays. In contrast, in vivo competition assays revealed that ompA and pgtE mutants underwent attenuated growth in liver, cardiac blood, spleen, lung, and kidney compared to a wild-type strain (CVCC3378). When tested in SPF chickens, ompA or pgtE gene inactivation substantially reduced organ colonisation and delayed systemic infection compared with the wild-type strain. Colonisation was restored in S. Enteritidis mutants by reintroduction of the whole ompA or pgtE gene with the native promoters. The results of this study demonstrate that ompA and pgtE play an important role in the pathogenesis of S. Enteritidis and its ability to infect chickens.

Endogenous Retroelements and the Host Innate Immune Sensors

The ability to distinguish between self and nonself is the fundamental basis of the immune system in all organisms. The conceptual distinction between self and nonself, however, breaks down when it comes to endogenous retroviruses and other retroelements. While some retroelements retain the virus-like features including the capacity to replicate and reinvade the host genome, most have become inactive through mutations or host epigenetic silencing. And yet, accumulating evidence suggests that endogenous retroelements, both active and inactive, play important roles not only in pathogenesis of immune disorders, but also in proper functioning of the immune system. This review discusses the recent development in our understanding of the interaction between retroelements and the host innate immune system. In particular, it focuses on the impact of retroelement transcripts on the viral RNA sensors such as Toll-like receptors, RIG-I-like receptors, protein kinase R, and the inflammasomes.

Comprehensive analysis of TEM methods for LiFePO4/FePO4 phase mapping: spectroscopic techniques (EFTEM, STEM-EELS) and STEM diffraction techniques (ACOM-TEM)

Transmission electron microscopy (TEM) has been used intensively in investigating battery materials, e.g. to obtain phase maps of partially (dis)charged (lithium) iron phosphate (LFP/FP), which is one of the most promising cathode material for next generation lithium ion (Li-ion) batteries. Due to the weak interaction between Li atoms and fast electrons, mapping of the Li distribution is not straightforward. In this work, we revisited the issue of TEM measurements of Li distribution maps for LFP/FP. Different TEM techniques, including spectroscopic techniques (energy filtered (EF)TEM in the energy range from low-loss to core-loss) and a STEM diffraction technique (automated crystal orientation mapping (ACOM)), were applied to map the lithiation of the same location in the same sample. This enabled a direct comparison of the results. The maps obtained by all methods showed excellent agreement with each other. Because of the strong difference in the imaging mechanisms, it proves the reliability of both the spectroscopic and STEM diffraction phase mapping. A comprehensive comparison of all methods is given in terms of information content, dose level, acquisition time and signal quality. The latter three are crucial for the design of in-situ experiments with beam sensitive Li-ion battery materials. Furthermore, we demonstrated the power of STEM diffraction (ACOM-STEM) providing additional crystallographic information, which can be analyzed to gain a deeper understanding of the LFP/FP interface properties such as statistical information on phase boundary orientation and misorientation between domains.

QM/MM investigation of the catalytic mechanism of angiotensin-converting enzyme

Angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II and degrades bradykinin and other vasoactive peptides. ACE inhibitors are used to treat diseases such as hypertension and heart failure. It is thus highly desirable to understand the catalytic mechanism of ACE, as this should facilitate the design of more powerful and selective ACE inhibitors. ACE exhibits two different active domains, the C-domain and the N-domain. In this work, we systematically investigated the inhibitor- and substrate-binding patterns in the N-domain of human ACE using a combined quantum mechanical and molecular mechanical approach. The hydrolysis of hippuryl-histidyl-leucine (HHL) as catalyzed by the N-domain of human somatic ACE was explored, and the effects of chloride ion on the overall reaction were also investigated. Two models, one with and one without a chloride ion at the first binding position, were then designed to examine the chloride dependence of inhibitor-substrate binding and the catalytic mechanism. Our calculations indicate that the hydrolysis reaction follows a stepwise general base/general acid catalysis path. The estimated mean free energy barrier height in the two models is about 15.6 kcal/mol, which agrees very well with the experimentally estimated value of 15.8 kcal/mol. Our simulations thus suggest that the N-domain is in a mixed form during ACE-catalyzed hydrolysis, with the single-chloride-ion and the double-chloride-ion forms existing simultaneously. Graphical Abstract Superposition of ACE C- and N- domains.

Association of fat-mass and obesity-associated gene FTO rs9939609 polymorphism with the risk of obesity among children and adolescents: a meta-analysis

OBJECTIVE

To elucidate the association of fat-mass and obesity-associated gene (FTO) rs9939609 polymorphism with obesity among children and adolescents.

METHODS

A literature search was conducted in PubMed, MEDLINE, Springer, and Google scholar to identify eligible studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used for four models: co-dominant model (AA vs. TT, AT vs. TT), dominant model (AA + AT vs. TT), recessive model (AA vs. AT + TT), and allelic model (A vs. T). Subgroup analyses stratified by ethnicity (Caucasian, others) and participants (children, children and adolescents) were assessed under allelic model. The heterogeneity and publication bias were examined.

RESULTS

This meta-analysis included 12 eligible studies consisting 5,000 cases and 9,853 controls. The results revealed that FTO rs9939609 polymorphism was significantly associated with the increased risk of obesity in co-dominant model (AA vs. TT: OR = 1.91, 95% CI: 1.47-2.48, p < 0.01; AT vs. TT: OR = 1.18, 95% CI: 1.02-1.38, p = 0.03), dominant model (AA + AT vs. TT: OR = 1.47, 95% CI: 1.35-1.59, p < 0.01), recessive model (AA vs. AT + TT: OR = 1.79, 95% CI: 1.47-2.17, p < 0.01), and allelic model (A vs. T: OR = 1.39, 95% CI: 1.22-1.58, p < 0.01). Similar results were obtained for the subgroup analyses stratified by ethnicity and participants under allelic model.

CONCLUSIONS

FTO rs9939609 polymorphism is associated with the increased risk of obesity among children and adolescents, especially the homozygous carriers.

A novel microbead-based microfluidic device for rapid bacterial identification and antibiotic susceptibility testing

Effective treatment of infectious diseases depends on the ability to rapidly identify the infecting bacteria and the use of sensitive antibiotics. The currently used identification assays usually take more than 72 h to perform and have a low sensitivity. Herein, we present a microbead-based microfluidic platform that is highly sensitive and rapid for bacterial detection and antibiotic sensitivity testing. The platform includes four units, one of which is used for bacterial identification and the other three are used for susceptibility testing. Our results showed that Escherichia coli O157 at a cell density range of 10(1)-10(5) CFU/μL could be detected within 30 min. Additionally, the effects of three antibiotics on E. coli O157 were evaluated within 4-8 h. Overall, this integrated microbead-based microdevice provides a sensitive, rapid, reliable, and highly effective platform for the identification of bacteria, as well as antibiotic sensitivity testing.

Resonantly pumped single-mode channel waveguide Er:YAG laser with nearly quantum defect limited efficiency

We demonstrated the continuous-wave operation of a resonantly pumped Er:YAG single-mode channel waveguide laser with diffraction-limited output and nearly quantum defect limited efficiency. Using a longitudinally core-pumped, nearly square (61.2 μm×61.6 μm) Er3+:YAG waveguide embedded in an undoped YAG cladding, an output power of 9.1 W with a slope efficiency of 92.8% (versus absorbed pump power) has been obtained. To the best of our knowledge, this optical-to-optical efficiency is the highest ever demonstrated for a channel waveguide laser.

Influence of the XbaI polymorphism in the estrogen receptor-α gene on human spermatogenic defects

Polymorphisms of estrogen receptor (ER) genes have been implicated in male infertility, but studies of this association have produced conflicting results. The present study was conducted to examine whether polymorphisms within the ERα and ERβ genes are susceptibility factors for human male idiopathic infertility in Chinese men. We investigated the association between the ERα gene gene and PvuII and XbaI polymorphisms and the ERβ gene and RsaI and AluI polymorphisms and idiopathic male infertility in Han Chinese men. A total of 204 men with oligozoospermia (sperm count <20 x 10(6)/mL) or azoospermia and 252 fertile control men were included in this study. The analysis revealed a strong association between the XbaI genotype distribution and impaired spermatogenesis (P = 0.0018). The frequency of the G allele was significantly lower in patients than in controls (P = 0.003). Furthermore, serum levels of follicle-stimulating hormone and luteinizing hormone in XbaI AA carriers were significantly higher than those in AG or GG carriers. Our findings further support a possible role of ERα in male infertility. Further studies are needed to replicate our findings, as well as to elucidate more fully the biological mechanisms of the modulation of ERα on human spermatogenesis.

[The effect of nicotinamide N-methytransferase overexpression on biological behaviors of SMMC7721 hepatocellar carcinoma cell line]

OBJECTIVE

To study the effect of over expressed nicotinamide N-methytransferase (NNMT) on the malignant biological behaviors of hepatocellular carcinoma cell line SMMC7721.

METHODS

The cells transfected with SMMC/NNMT abbreviated as S/NNMT, parental cells including the negative control which transfected with SMMC/pcDNA3. 1 abbreviated as S/P and parental group which abbreviated S. MTT assay and Plate Clone Formation Assay, cell adhension assay and invasion assay were applied to evaluate the effect of NNMT overexpression on the malignant biological behaviors of hepatocellular carcinoma cell line SMMC7721.

RESULTS

Compared with the negative control and parental group, MTT assay and Plate Clone Formation Assay demonstrated that over expression of NNMT in SMMC7721 cells could not influence the proliferation clone formation of SMMC7721 cells (P > 0.05). Over expression of NNMT in SMMC7721 cells significantly enhanced the ability of invasion and adhension (P < 0.001).

CONCLUSION

NNMT gene can partially influence the malignant behaviors of hepatocellular carcinoma cellline SMMC7721 and increased the ability of invasion and adhension.

WAP four-disulfide core domain protein 2 mediates the proliferation of human ovarian cancer cells through the regulation of growth- and apoptosis-associated genes

The WAP four-disulfide core domain protein 2 (WFDC2) is frequently overexpressed in epithelial ovarian cancer cells and has been proposed as a potential biomarker. The biological function of WFDC2 in tumor progression remains unclear. In this study, the stable expression of short hairpin RNA (shRNA) against WFDC2 in the human ovarian SKOV3 cell line was established. Cell proliferation in vitro was determined by MTT assay. Cell cycle and apoptosis were analyzed by FACS. The expression of genes related to cell proliferation and survival was detected by real-time RT-PCR and western blotting. In vivo tumor growth assay was performed by establishing WFDC2-knockdown xenografts in nude mice and monitoring tumor growth. The expression of WFDC2, Ki67 and activated caspase-3 was analyzed by immunohistochemistry in order to determine the role of WFDC2 in proliferation and apoptosis. Our results revealed that the silencing of WFDC2 abolished ovarian cancer cell proliferation, suppressing tumor formation and growth in ovarian cancer cells both in vitro and in vivo. The knockdown of WFDC2 induced upregulation of Fasl and the downregulation of cyclin D1 activated caspase-3 and Ki67. These results indicate that WFDC2 plays a crucial role in tumor formation and growth in ovarian cancer cells. WFDC2 may be a potential therapeutic target for epithelial ovarian cancer.

Effect of triptolide on progesterone production from cultured rat granulosa cells

Triptolide(CAS 38748-32-2), a major active component of Tripterygium wilfordii Hook F (TWHF), is known to have multiple pharmacological activities. However, studies have also shown that triptolide is highly disrupt to the reproductive system by disrupting normal steroid hormone signaling. In the present study, we investigated the effect of triptolide (5, 10, or 20 nM for 24 h) on progesterone production by rat granulosa cells. Triptolide inhibited both basal and human chorionic gonadotropin (HCG)- and 8-bromo-cAMP-stimulated progesterone production as revealed by RIA assay. Furthermore, the HCG-evoked increase in cellular cAMP content was also inhibited by triptolide, indicating that disruption of the cAMP/PKA signaling pathway may mediate the deleterious effects of triptolide on progesterone regulation. In addition, triptolide inhibited 25-OH-cholesterol-stimulated progesterone production, suggesting that activity of the P450 side chain cleavage (P450scc) enzyme was also be inhibited by triptolide. Western blot and quantitative real-time PCR (qRT-PCR) assays further revealed that triptolide decreased mRNA and protein expression of P450scc and the steroidogenic regulatory (StAR) protein in granulosa cells. In contrast, cell viability tests using 3-(4,5-dimethyl-thiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) indicated that triptolide did not cause measurable cell death at doses that suppressed steroidogenesis. The reproductive toxicity of triptolide may be caused by disruption of cAMP/PKA-mediated expression of a number of progesterone synthesis enzymes or regulatory proteins, leading to reduced progesterone synthesis and reproductive dysfunction.

Expression profiles of seven channel catfish antimicrobial peptides in response to Edwardsiella ictaluri infection

Using quantitative polymerase chain reaction (QPCR), the relative transcriptional levels of seven channel catfish antimicrobial peptide (AMP) genes (NK-lysin type 1, NK-lysin type 2, NK-lysin type 3, bactericidal permeability-increasing protein, cathepsin D, hepcidin and liver-expressed AMP 2) in response to Edwardsiella ictaluri infection were determined. None of the AMP genes tested was significantly upregulated at 2 h post-infection. Hepcidin was the only one that was significantly (P<0.05) upregulated at 4, 6 and 12 h post-infection. At 24 and 48 h post-infection, four AMPs (hepcidin, NK-lysin type 1, NK-lysin type 3 and cathepsin D) were significantly (P<0.05) upregulated. Among all the AMPs that were significantly upregulated at different time points, hepcidin at 4, 6 and 12 h post-infection was upregulated the most. When catfish were injected with different doses of E. ictaluri, all lethal doses were able to induce significant (P <0.05) upregulation of hepcidin in the posterior kidney, whereas sublethal doses failed to induce any significant upregulation of hepcidin. In vitro growth studies revealed that the presence of synthetic hepcidin peptide at a concentration of 16 μm or higher significantly inhibited the cell proliferation of E. ictaluri. Taken together, our results suggest that hepcidin might play an important role in the channel catfish defence against E. ictaluri infection.

Microbialites and global environmental change across the Permian-Triassic boundary: a synthesis

Permian-Triassic boundary microbialites (PTBMs) are thin (0.05-15 m) carbonates formed after the end-Permian mass extinction. They comprise Renalcis-group calcimicrobes, microbially mediated micrite, presumed inorganic micrite, calcite cement (some may be microbially influenced) and shelly faunas. PTBMs are abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents but are rare in higher latitudes, likely inhibited by clastic supply on Pangaea margins. PTBMs occupied broadly similar environments to Late Permian reefs in Tethys, but extended into deeper waters. Late Permian reefs are also rich in microbes (and cements), so post-extinction seawater carbonate saturation was likely similar to the Late Permian. However, PTBMs lack widespread abundant inorganic carbonate cement fans, so a previous interpretation that anoxic bicarbonate-rich water upwelled to rapidly increase carbonate saturation of shallow seawater, post-extinction, is problematic. Preliminary pyrite framboid evidence shows anoxia in PTBM facies, but interbedded shelly faunas indicate oxygenated water, perhaps there was short-term pulsing of normally saturated anoxic water from the oxygen-minimum zone to surface waters. In Tethys, PTBMs show geographic variations: (i) in south China, PTBMs are mostly thrombolites in open shelf settings, largely recrystallised, with remnant structure of Renalcis-group calcimicrobes; (ii) in south Turkey, in shallow waters, stromatolites and thrombolites, lacking calcimicrobes, are interbedded, likely depth-controlled; and (iii) in the Middle East, especially Iran, stromatolites and thrombolites (calcimicrobes uncommon) occur in different sites on open shelves, where controls are unclear. Thus, PTBMs were under more complex control than previously portrayed, with local facies control playing a significant role in their structure and composition.

Evaluation of an in vitro cell assay to select attenuated bacterial mutants of Aeromonas hydrophila and Edwardsiella tarda to channel catfish

AIMS

To evaluate the feasibility of using an in vitro cell assay to select attenuated bacterial mutants.

METHODS AND RESULTS

Using catfish gill cells G1B, the feasibility of using an in vitro assay instead of in vivo virulence assay using live fish to select attenuated bacterial mutants was evaluated in this study. Pearson correlation analysis between in vitro virulence to G1B cells and in vivo virulence of Aeromonas hydrophila and Edwardsiella tarda revealed that there was a significant correlation between the two (r = -0.768, P value = 3.7 × 10(-16)).

CONCLUSIONS

The in vitro cell assay might be initially used to screen large quantities of bacteria to select attenuated mutants of catfish pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

The in vitro cell assay using catfish gill cells to identify attenuated mutants of catfish pathogens will reduce cost involved in the in vivo virulence assay that requires many fish and aquariums.

An in vitro screening method to evaluate chemicals as potential chemotherapeutants to control Aeromonas hydrophila infection in channel catfish

AIMS

To develop an in vitro screening method to be used for identifying potential effective chemotherapeutants to control Aeromonas hydrophila infections.

METHODS AND RESULTS

Using catfish gill cells G1B and four chemicals (hydrogen peroxide, sodium chloride, potassium permanganate and D-mannose), the feasibility of using an in vitro screening method to identify potential effective chemotherapeutants was evaluated in this study. In vitro screening results revealed that, at concentration of 100 mg l⁻¹, H₂O₂ was the only chemical tested that was able to completely abolish the attachment and invasion of Aer. hydrophila to catfish gill cells. In vivo virulence studies using live channel catfish through bath immersion confirmed that H₂O₂ was the only chemical tested that was able to significantly (P < 0·001) reduce the mortality (from 90 or 100% to 0 or 20%) caused by Aer. hydrophila infections.

CONCLUSIONS

The in vitro screening method using catfish gill cells G1B could be used to initially identify potential effective chemotherapeutants to control Aer. hydrophila.

SIGNIFICANCE AND IMPACT OF THE STUDY

An in vitro screening method using catfish gill cells to identify potential effective chemotherapeutants described here will cut cost in research compared with the method of using live fish to screen lead compounds for fish disease control.

First-principles study of NO adsorbed Ni(100) surface

The geometric, electronic and magnetic properties of NO molecules adsorbed on the Ni(100) surface are investigated by the first-principles calculation on the basis of the density functional theory (DFT). The NO molecules are predicted to be chemisorbed at hollow site with an upright configuration at 0.125 ML and 0.5 ML coverages. After adsorption, the magnetic moment is significantly suppressed for surface Ni atom and almost quenched for NO molecule. This behavior can be reasonably explained by the difference of the backdonation process between the spin-up and spin-down electronic states, which is demonstrated by the spin-resolved differential charge density map.