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Find video protocols related to scientific articles indexed in Pubmed.
Detection of molecular binding via charge-induced mechanical response of optical fibers.
Chem Sci
PUBLISHED: 11-20-2014
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We report a charge sensitive optical detection technique for label-free study of molecular interactions. Traditional label-free optical detection techniques largely rely on the detection of the mass of a molecule, which are insensitive to small molecules. In contrast, the present technique detects the charge of a molecule, where the signal does not diminish with the size of the molecule, thus capable for studying small molecules. In addition, the technique is compatible with the standard microplate platform, making it suitable for high-throughput screening of drug candidates. Using the technique, we have detected 0.2 nM anti-BSA and 15 ?M anti-cancer drug (imatinib) with an enzyme modified surface. The achieved effective charge detection limit is ~0.25 electron charge/?m(2), corresponding to ~0.3 fg/mm(2) for imatinib, which is orders of magnitude better than traditional label-free optical detection methods.
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Genetic and phenotypic characterization of Candida albicans strains isolated from infectious disease patients in Shanghai.
J. Med. Microbiol.
PUBLISHED: 10-30-2014
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Candida albicans, as an opportunistic pathogen, can cause superficial and life-threatening candidiasis in immunocompromised individuals. The formation of surface-associated biofilms and the appearance of drug resistance pose a significant challenge for clinical intervention. In this study, a total of 104 hospital-acquired C. alibcans clinical isolates collected from sterile sites and mucosal lesions of 92 infectious disease patients in Shanghai Public Health Clinical Center were analyzed. The resistance rate to fluconazole, itraconazole and voriconazole were 12.5%, 15.4% and 11.5% respectively. MLST analysis identified 63 diploid sequence types (DSTs) with a decentralized phylogeny, of which 37 DSTs (58.7%) had not been reported in the online MLST database. Loss of heterozygosity was observed in ACC1 and ADP1 sequences obtained from six sequential isolates from a patient receiving antifungal treatment, which exemplified the effect of microevolution on C. albicans genetic alterations. The biofilm formation capability, an important virulence trait of C. albicans, was variable among strains isolated from different anatomical sites (p=0.0302) and affected by genotypes (p=0.0185). The mRNA level of the azole antifungal target ERG11 gene and efflux pump genes (CDR1, CDR2, and MDR1) were detected in 9%-18.1% of azole-resistant and susceptible-dose dependent (S-DD) isolates. Twelve mutations encoding distinct amino acid substitutions in ERG11 were found in azole-resistant and S-DD isolates. Among them, A114S, Y132H and Y257H substitution in the ERG11 gene may be primarily related to azole resistance. Taken together, we observed a high level of diversity within C. albicans isolates. Multiple inter-related underlying mechanisms, including genetic and environmental factors, may account for high surface adhesion or azole resistance in clinical C. albicans infection.
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CD8 T Cells Are Involved in Skeletal Muscle Regeneration through Facilitating MCP-1 Secretion and Gr1high Macrophage Infiltration.
J. Immunol.
PUBLISHED: 10-22-2014
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Inflammatory microenvironments play a key role in skeletal muscle regeneration. The infiltration of CD8 T cells into injured muscle has been reported. However, the role of CD8 T cells during skeletal muscle regeneration remains unclear. In this study, we used cardiotoxin-induced mouse skeletal muscle injury/regeneration model to investigate the role of CD8 T cells. Muscle regeneration was impaired and matrix deposit was increased in CD8?-deficient mice compared with wild-type (WT) mice whose CD8 T cells were infiltrated into damaged muscle after cardiotoxin injection. Adoptive transfer of CD8 T cells to CD8?-deficient mice improved muscle regeneration and inhibited matrix remodeling. Compared with WT mice, CD8? deficiency limited the recruitment of Gr1(high) macrophages (MPs) into muscle, resulting in the reduction of satellite cell number. The expression of MCP-1 (MCP-1/CCL2), which regulates the migration of Gr1(high) MPs, was reduced in CD8?-deficient mice compared with WT mice. Coculture CD8 T cells with MPs promoted MCP-1 secretion. The i.m. injection of MCP-1 markedly promoted the recruitment of Gr1(high) MPs and improved muscle regeneration in CD8?-deficient mice. We conclude that CD8 T cells are involved in skeletal muscle regeneration by regulating the secretion of MCP-1 to recruit Gr1(high) MPs, which facilitate myoblast proliferation.
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[A standard protocol for detection of EGFR mutations in cytologic specimens].
Zhonghua Zhong Liu Za Zhi
PUBLISHED: 10-21-2014
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The aim of this study was to establish a standard protocol for detection of EGFR mutations in cytologic specimens.
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Nicorandil improves myocardial function by regulating plasma nitric oxide and endothelin-1 in coronary slow flow.
Coron. Artery Dis.
PUBLISHED: 10-18-2014
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Coronary slow flow (CSF) is a special coronary microvascular disorder. The pathogenesis and effective therapeutics of CSF remain unclear. This study aimed to evaluate the global and regional functions of the left ventricle (LV) and investigate the efficacy of nicorandil in patients with CSF.
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Risk of Cigarette Smoking Initiation During Adolescence Among US-Born and Non-US-Born Hispanics/Latinos: The Hispanic Community Health Study/Study of Latinos.
Am J Public Health
PUBLISHED: 10-17-2014
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Objectives. We assessed risk of cigarette smoking initiation among Hispanics/Latinos during adolescence by migration status and gender. Methods. The Hispanic Community Health Study/Study of Latinos (HCHS/SOL) surveyed persons aged 18 to 74 years in 2008 to 2011. Our cohort analysis (n?=?2801 US-born, 13?200 non-US-born) reconstructed participants' adolescence from 10 to 18 years of age. We assessed the association between migration status and length of US residence and risk of cigarette smoking initiation during adolescence, along with effects of gender and Hispanic/Latino background. Results. Among individuals who migrated by 18 years of age, median age and year of arrival were 13 years and 1980, respectively. Among women, but not men, risk of smoking initiation during adolescence was higher among the US-born (hazard ratio [HR]?=?2.10; 95% confidence interval [CI]?=?1.73, 2.57; P?
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Association of Chronic Hepatitis C Infection With T-Cell Phenotypes in HIV-Negative and HIV-Positive Women.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 10-15-2014
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Hepatitis C virus (HCV) viremia is thought to have broad systemic effects on the cellular immune system that go beyond its impact on just those T cells that are HCV specific. However, previous studies of chronic HCV and circulating T-cell subsets (activation and differentiation phenotypes) in HIV negatives used general population controls, rather than a risk-appropriate comparison group. Studies in HIV positives did not address overall immune status (total CD4 count).
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Numerical solution of the nonlinear Schrödinger equation with wave operator on unbounded domains.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 09-23-2014
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In this paper, we generalize the unified approach proposed in Zhang et al. [J. Zhang, Z. Xu, and X. Wu, Phys. Rev. E 78, 026709 (2008)] to design the nonlinear local absorbing boundary conditions (LABCs) for the nonlinear Schrödinger equation with wave operator on unbounded domains. In fact, based on the methodology underlying the unified approach, we first split the original equation into two parts-the linear equation and the nonlinear equation-then achieve a one-way operator to approximate the linear equation to make the wave outgoing, and finally combine the one-way operator with the nonlinear equation to achieve the nonlinear LABCs. The stability of the equation with the nonlinear LABCs is also analyzed by introducing some auxiliary variables, and some numerical examples are presented to verify the accuracy and effectiveness of our proposed method.
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Molecular scale origin of surface plasmon resonance biosensors.
Anal. Chem.
PUBLISHED: 09-04-2014
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Surface plasmon resonance (SPR) has become an indispensable tool for label-free detection and quantification of molecular binding. Traditionally, the principle of SPR biosensors is described with a stratified medium model, in which discrete molecules are approximated with a uniform thin film. With the recent technical advances, SPR can now detect extremely low coverage of molecules, which raises the question of the validity of the traditional model. Here, we present combined theoretical, numerical and experimental analysis of SPR detection principle by considering the discrete nature of the molecules (particles). Our results show that the stratified medium model can provide reasonable description of SPR biosensors for relatively high coverage and weakly scattering samples. However, interference between the SPR images of individual particles needs to be considered for high spatial resolution images and for strong scattering samples at certain incident angles of light.
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Plasmonic imaging of electrochemical oxidation of single nanoparticles.
J. Am. Chem. Soc.
PUBLISHED: 08-27-2014
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Measuring electrochemical activities of nanomaterials is critical for creating novel catalysts, for developing ultrasensitive sensors, and for understanding fundamental nanoelectrochemistry. However, traditional electrochemical methods measure a large number of nanoparticles, which wash out the properties of individual nanoparticles. We report here a study of transient electrochemical oxidation of single Ag nanoparticles during collision with an electrode and voltammetry of single nanoparticles immobilized on the electrode using a plasmonic-based electrochemical current microscopy. This technique images both electrochemical reaction and size of the same individual nanoparticle, enabling quantitative examination of size-dependent electrochemical activities at single nanoparticle level. The imaging capability further allows detection of the reaction kinetics of each individual nanoparticle and analysis of the average behaviors of multiple nanoparticles. The average kinetics and size dependence can be accurately described by the Tafel equation, but there is a large variability between different nanoparticles, which underscores the importance of single nanoparticle analysis.
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A new prognostic score for AIDS-related lymphomas in the Rituximab-era.
Haematologica
PUBLISHED: 08-22-2014
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While the International Prognostic Index is commonly used to predict outcomes in immunocompetent patients with aggressive B-cell Non-Hodgkin Lymphomas, HIV-infection is an important competing risk for death in patients with AIDS-related lymphomas. We investigated whether a newly created prognostic score (AIDS-related lymphoma International Prognostic Index) could better assess risk of death in patients with AIDS-related lymphomas. We randomly divided a dataset of 487 patients newly diagnosed with AIDS-related lymphomas and treated with rituximab-containing chemoimmunotherapy into a training (n=244) and validation set (n=243). We examined the association of HIV-related and other known risk factors with overall survival in both sets independently. We defined a new score (AIDS-related lymphoma International Prognostic Index) by assigning weights to each significant predictor (age-adjusted international prognostic index, extranodal sites, HIV-score [composed of CD4 count, viral load, and prior history of AIDS]) with three risk categories similar to the age-adjusted International Prognostic Index (low, intermediate and high risk). We compared the prognostic value for overall survival between AIDS-related lymphoma International Prognostic Index and age-adjusted International Prognostic Index in the validation set and found that the AIDS-related lymphoma International Prognostic Index performed significantly better in predicting risk of death than the age-adjusted International Prognostic Index (p=0.004) and better discriminated risk of death between each risk category (p=0.015 vs. p=0.13).
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Spinal cord stimulation exerts analgesia effects in chronic constriction injury rats via suppression of the TLR4/NF-?B pathway.
Neurosci. Lett.
PUBLISHED: 08-19-2014
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Spinal cord stimulation (SCS) is an established method for treating chronic neuropathic pain. However, the mechanisms underlying the pain relieving effect of SCS on neuropathic pain remain unclear. Evidence shows that the toll-like receptor 4 (TLR4)/nuclear factor (NF)-?B signal transduction pathway plays a key role in chronic neuropathic pain. We investigated changes in the TLR4/NF-?B pathway and downstream pro-inflammatory cytokine expression in L4-6 spinal cord following SCS. Neuropathic pain was induced through chronic constriction injury (CCI) of the sciatic nerve in rats. Mechanical withdrawal threshold (MWT) was assessed before surgery and on days 1, 4, 7, and 14 after CCI. During days 11-14, the nerve-injured rats were treated with SCS for 30 min per day. Compared with the control group, the CCI rats displayed a significantly decreased MWT. After SCS for 3 days, the expression of TLR4/NF-?B and the levels of interleukin(IL)-1?, IL-6, and tumor necrosis factor (TNF)-? in the spinal cord were lower in the SCS group compared to those in the CCI and sham spinal cord stimulation (S-SCS) groups. These results indicate that SCS could effectively attenuate neuropathic pain in CCI rats by inhibiting the activation of the TLR4/NF-?B signaling pathway and by inhibiting the up-regulation of pro-inflammatory cytokines in the spinal cord.
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All-IP wireless sensor networks for real-time patient monitoring.
J Biomed Inform
PUBLISHED: 08-19-2014
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This paper proposes the all-IP WSNs (wireless sensor networks) for real-time patient monitoring. In this paper, the all-IP WSN architecture based on gateway trees is proposed and the hierarchical address structure is presented. Based on this architecture, the all-IP WSN can perform routing without route discovery. Moreover, a mobile node is always identified by a home address and it does not need to be configured with a care-of address during the mobility process, so the communication disruption caused by the address change is avoided. Through the proposed scheme, a physician can monitor the vital signs of a patient at any time and at any places, and according to the IPv6 address he can also obtain the location information of the patient in order to perform effective and timely treatment. Finally, the proposed scheme is evaluated based on the simulation, and the simulation data indicate that the proposed scheme might effectively reduce the communication delay and control cost, and lower the packet loss rate.
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Therapeutic implications of CD1d expression and tumor-infiltrating macrophages in pediatric medulloblastomas.
J. Neurooncol.
PUBLISHED: 08-13-2014
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Immunobiology of medulloblastoma (MB), the most common malignant brain tumor in children, is poorly understood. Although tumor cells in some MBs were recently shown to express CD1d and be susceptible to V?24-invariant natural killer T (NKT)-cell cytotoxicity, the clinical relevance of CD1d expression in MB patients remains unknown. We investigated the expression of CD1d in pediatric MBs and correlated with molecular and clinical characteristics. Specifically, we explored if NKT cell therapy can be targeted at a subset of pediatric MBs with poorer prognosis. Particularly, infantile MBs have a worse outcome because radiotherapy is delayed to avoid neurocognitive sequelae. Immunohistochemistry for CD1d was performed on a screening set of 38 primary pediatric MBs. Gene expression of the membrane form of M2 macrophage marker, CD163, was studied in an expanded cohort of 60 tumors. Outcome data was collected prospectively. Thirteen of 38 MBs (34.2 %) expressed CD1d on immunohistochemistry. CD1d was expressed mainly on MB tumor cells, and on some tumor-associated macrophages. Majority (18/22, 82 %) of non sonic-hedgehog/Wingless-activated MBs (group 3 and 4) were CD1d-negative (p = 0.05). A subset of infantile MBs (4/9, 44.4 %) expressed CD1d. Macrophages infiltrating MB expressed CD163 apart from CD1d. Molecular subtypes demonstrated statistical differences in CD163 expression, SHH-tumors were the most enriched (p = 0.006). Molecular and clinical subtypes of pediatric MB exhibit distinct differences in CD1d expression, which have important therapeutic implications. High CD1d expression in infantile MBs offers potential new immunotherapeutic treatment with NKT cell therapy in infants, where treatment is suboptimal due delayed radiotherapy.
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Investigation of the role of organic cation transporter 2 (OCT2) in the renal transport of guanfacine, a selective ?2A-adrenoreceptor agonist.
Xenobiotica
PUBLISHED: 08-13-2014
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Abstract 1.? Guanfacine is a selective ?2A-adrenoreceptor agonist primarily excreted as its unchanged form through urine in human. This study was to investigate the involvement of organic cation transporter 2 (OCT2) in the renal tubular secretion of guanfacine. 2.? Transport of guanfacine was characterized using human embryonic kidney (HEK293) cells expressing human OCT2 (hOCT2). The inhibitory effect of cimetidine on guanfacine uptake was also examined. In addition, in vivo pharmacokinetic study was conducted in rats to assess the effects of cimetidine on the pharmacokinetics of guanfacine. 3.? The accumulation of guanfacine in hOCT2-transfected HEK293 cells was both time- and concentration-dependent, and markedly higher than that in mock cells. The apparent Km and Vmax values of guanfacine uptake by hOCT2 were 96.19?±?7.49??M and 13.03?±?0.49?nmol/mg protein/min, respectively. Guanfacine transport mediated by hOCT2 was significantly inhibited by a typical OCT2 inhibitor cimetidine with an IC50 value of 93.82?±?1.13??M. Co-administration of cimetidine significantly decreased the plasma clearance (CLp) as well as the renal clearance (CLr) of guanfacine in rats in a dose-dependent manner, resulting in a noticeable increase in the systemic exposure of guanfacine. 4.? These results indicated that OCT2 may be involved in the renal disposition of guanfacine.
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Assessment of Transfection of AdCMV-EGFP to Rat Submandibular Gland Cells.
Cell Biochem. Biophys.
PUBLISHED: 08-10-2014
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We evaluated the efficiency of transfecting adenoviral vectors encoding enhanced green fluorescent protein (AdCMV-EGFP) into rat submandibular gland cells and the effects of gene transfer on cell proliferation and secretory function. Isolated submandibular gland cells were transfected with different titers (or multiplicity of infection, MOI) of AdCMV-EGFP. The transfection efficiency was evaluated by quantifying EGFP-positive cells by inverted fluorescence microscopy, cell proliferation by MTT assay, and cell secretory activity by measuring ?-amylase in culture medium. A transfection efficiency of up to 70.8 % was achieved in submandibular gland cells. MTT assay showed that increased viral titers resulted in significant inhibition of cell proliferation, which occurs on day 5 post-transfection. Simultaneously, the amylase levels started to reduce with a significant decrease on day 7 after transfection. The results show that AdCMV-EGFP transfection of submandibular gland cells at higher MOI results in cytotoxicity, decreased cell proliferation, and secretory function. However, the lower adenoviral titers (e.g., 200 particles/cell) could be an efficient and safe labeling tool for gene transfer to submandibular gland cells.
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Postnatal overfeeding promotes early onset and exaggeration of high-fat diet-induced nonalcoholic fatty liver disease through disordered hepatic lipid metabolism in rats.
J. Nutr. Biochem.
PUBLISHED: 08-04-2014
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Exposure to overnutrition in critical or sensitive developmental periods may increase the risk of developing obesity and metabolic syndrome in adults. Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome, but the relationship among postnatal nutrition, lipid metabolism, and NAFLD progression during development remains poorly understood. Here we investigated in a rat model whether postnatal overfeeding increases susceptibility to NAFLD in response to a high-fat diet. Litters from Sprague-Dawley dams were culled to three (small litters) or ten (normal litters) pups and then weaned onto a standard or high-fat diet at postnatal day 21 to generate normal-litter, small-litter, normal-litter/high-fat, and small-litter/high-fat groups. At age 16weeks, the small-litter and both high-fat groups showed obesity, dyslipidemia, and insulin resistance. Hepatic disorders appeared earlier in the small-litter/high-fat rats with greater liver mass gain and higher hepatic triglycerides and steatosis score versus normal-litter/high-fat rats. Hepatic acetyl-CoA carboxylase activity and mRNA expression were increased in small-litter rats and aggravated in small-litter/high-fat rats but not in normal-litter/high-fat rats. The high expression in small-litter/high-fat rats coincided with high sterol regulatory element-binding protein-1c mRNA and protein expression. However, mRNA expression of enzymes involved in hepatic fatty acid oxidation (carnitine palmitoyltransferase 1) and output (microsomal triglyceride transfer protein) was decreased under a high-fat diet regardless of litter size. In conclusion, overfeeding related to small-litter rearing during lactation contributes to the NAFLD phenotype when combined with a high-fat diet, possibly through up-regulated hepatic lipogenesis.
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Detection and Quantification of Chloramphenicol in Milk and Honey Using Molecularly Imprinted Polymers: Canadian Penny-Based SERS Nano-Biosensor.
J. Food Sci.
PUBLISHED: 07-22-2014
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We integrated molecularly imprinted polymers with surface-enhanced Raman spectroscopy (MIPs-SERS) to develop an innovative nano-biosensor for the determination of chloramphenicol (CAP) in milk and honey products. Template molecule (CAP), functional monomer (acrylamide), cross-linking agent (ethylene glycol dimethacrylate), initiator (2,2'-azobis(isobutyronitrile)), and porogen (methanol) were employed to form MIPs via "dummy" precipitation polymerization. Static and kinetic studies validated the specific selectivity of MIPs toward CAP over nonimprinted polymers (imprinting factor >4). Canadian penny-based silver nano-structure was synthesized as SERS-active substrate for determination of CAP in food matrices. Collected spectra were processed by principal component analysis to differentiate various concentrations of CAP in foods. Partial least squares regression models showed good prediction values (R > 0.9) of actual spiked contents (0, 0.1, 0.5, 1, 5 ppm) of CAP in milk and honey. This developed nano-biosensor is low cost, requires little sample pretreatment, and can provide reliable detection of trace level of chemical hazards in food systems within a total of 15 min.
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Production of salidroside in metabolically engineered Escherichia coli.
Sci Rep
PUBLISHED: 07-14-2014
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Salidroside (1) is the most important bioactive component of Rhodiola (also called as "Tibetan Ginseng"), which is a valuable medicinal herb exhibiting several adaptogenic properties. Due to the inefficiency of plant extraction and chemical synthesis, the supply of salidroside (1) is currently limited. Herein, we achieved unprecedented biosynthesis of salidroside (1) from glucose in a microorganism. First, the pyruvate decarboxylase ARO10 and endogenous alcohol dehydrogenases were recruited to convert 4-hydroxyphenylpyruvate (2), an intermediate of L-tyrosine pathway, to tyrosol (3) in Escherichia coli. Subsequently, tyrosol production was improved by overexpressing the pathway genes, and by eliminating competing pathways and feedback inhibition. Finally, by introducing Rhodiola-derived glycosyltransferase UGT73B6 into the above-mentioned recombinant strain, salidroside (1) was produced with a titer of 56.9?mg/L. Interestingly, the Rhodiola-derived glycosyltransferase, UGT73B6, also catalyzed the attachment of glucose to the phenol position of tyrosol (3) to form icariside D2 (4), which was not reported in any previous literatures.
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Adiponectin reduces carotid atherosclerotic plaque formation in ApoE-/- mice: Roles of oxidative and nitrosative stress and inducible nitric oxide synthase.
Mol Med Rep
PUBLISHED: 06-26-2014
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Adiponectin (APN) is an important anti?atherogenic adipocytokine. The aim of the present study was to investigate the role of adiponectin in atherosclerotic plaque formation and clarify its mechanisms. An atherosclerosis model was induced by in vivo perivascular constrictive silica collar placement on the left common carotid arteries in male apolipoprotein E?deficient (ApoE?/?) mice. All of the mice were fed a high?fat diet, and divided into phosphate?buffered saline, adenovirus (Ad)???galactosidase and Ad?APN treatment groups. Compared with treatment of Ad???gal or PBS, Ad?APN treatment markedly reduced inducible nitric oxide synthase (iNOS) protein expression, decreased in nitric oxide/superoxide production, blocked peroxynitrite formation and reversed the progression of atherosclerotic lesions. Adiponectin may be a natural molecule that reduces atherosclerosis by inhibiting iNOS and consequently diminishing oxidative/nitrative stress.
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Detection of charges and molecules with self-assembled nano-oscillators.
Nano Lett.
PUBLISHED: 06-26-2014
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Detection of a single or small amount of charges and molecules in biologically relevant aqueous solutions is a long-standing goal in analytical science and detection technology. Here we report on self-assembled nano-oscillators for charge and molecular binding detections in aqueous solutions. Each nano-oscillator consists of a nanoparticle linked to a solid surface via a molecular tether. By applying an oscillating electric field normal to the surface, the nanoparticles oscillate, which is detected individually with ?0.1 nm accuracy by a plasmonic imaging technique. From the oscillation amplitude and phase, the charge of the nanoparticles is determined with a detection limit of ?0.18 electron charges along with the charge polarity. We further demonstrate the detection of molecular binding with the self-assembled nano-oscillators.
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The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.
Environ. Microbiol.
PUBLISHED: 06-06-2014
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Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V.?dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V.?dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V.?dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V.?dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V.?dahliae.
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?High resolution-magic-angle spinning NMR spectroscopy for metabolic phenotyping of Caenorhabditis elegans.
Anal. Chem.
PUBLISHED: 06-04-2014
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Analysis of model organisms, such as the submillimeter-size Caenorhabditis elegans, plays a central role in understanding biological functions across species and in characterizing phenotypes associated with genetic mutations. In recent years, metabolic phenotyping studies of C. elegans based on (1)H high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy have relied on the observation of large populations of nematodes, requiring labor-intensive sample preparation that considerably limits high-throughput characterization of C. elegans. In this work, we open new platforms for metabolic phenotyping of C. elegans mutants. We determine rich metabolic profiles (31 metabolites identified) from samples of 12 individuals using a (1)H NMR microprobe featuring high-resolution magic-angle coil spinning (HR-MACS), a simple conversion of a standard HR-MAS probe to ?HR-MAS. In addition, we characterize the metabolic variations between two different strains of C. elegans (wild-type vs slcf-1 mutant). We also acquire a NMR spectrum of a single C. elegans worm at 23.5 T. This study represents the first example of a metabolomic investigation carried out on a small number of submillimeter-size organisms, demonstrating the potential of NMR microtechnologies for metabolomics screening of small model organisms.
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Mohawk Promotes the Tenogenesis of Mesenchymal Stem Cells through Activation of the TGF? Signaling Pathway.
Stem Cells
PUBLISHED: 05-25-2014
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The transcription factor Mohawk (Mkx) is expressed in developing tendons and is an important regulator of tenogenic differentiation. However, the exact roles of Mkx in tendinopathy and tendon repair remain unclear. Utilizing gene expression Omnibus datasets and Immunofluorescence assays, we found that Mkx expression level was dramatically lower in human tendinopathy tissue and it is activated at specific stages of tendon development. In mesenchymal stem cells (MSCs), ectopic Mkx expression strikingly promoted tenogenesis more efficiently than Scleraxis (Scx), a well-known master transcription factor of tendon. Significantly higher levels of tenogenic gene expression and collagen fibril growth were observed with Mkx versus Scx. Interestingly, it was observed that Mkx dramatically up-regulated Scx through binding to the Tgfb2 promoter. Additionally, the transplantation of Mkx expressing-MSC sheets promoted tendon repair in a mouse model of Achilles-tendon defect. Taken together, these data shed light on previously unrecognized roles of Mkx in tendinopathy, tenogenesis, and tendon repair, as well as in regulating the TGF? pathway. Stem Cells 2014.
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Asymmetric varus and valgus stability of the anatomic cadaver knee and the load sharing between collateral ligaments and bearing surfaces.
J Biomech Eng
PUBLISHED: 05-14-2014
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Knee joint stability is important in maintaining normal joint motion during activities of daily living. Joint instability not only disrupts normal motion but also plays a crucial role in the initiation and progression of osteoarthritis. Our goal was to examine knee joint coronal plane stability under varus or valgus loading and to understand the relative contributions of the mechanisms that act to stabilize the knee in response to varus-valgus moments, namely, load distribution between the medial and lateral condyles and the ligaments. A robot testing system was used to determine joint stability in human cadaveric knees as described by the moment versus angular rotation behavior under varus and valgus loads at extension and at 30 deg and 90 deg of flexion. The anatomic knee joint was more stable in response to valgus than varus moments, and stability decreased with flexion angle. The primary mechanism for providing varus-valgus stability was the redistribution of the contact force on the articular surfaces from both condyles to a single condyle. Stretching of the collateral ligaments provided a secondary stabilizing mechanism after the lift-off of a condyle occurred. Compressive loads applied across the knee joint, such as would occur with the application of muscle forces, enhanced the ability of the articular surface to provide varus-valgus moment, and thus, helped stabilize the joint in the coronal plane. Coupled internal/external rotations and anteroposterior and medial-lateral translations were variable and in the case of the rotations were often as large as the varus-valgus rotations created by the applied moment.
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Local absorbing boundary conditions for a linearized Korteweg-de Vries equation.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 05-13-2014
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The aim of this paper is to construct highly accurate local absorbing boundary conditions for a linearized Korteweg-de Vries equation on unbounded domain. The local absorbing boundary conditions are derived by Padé approximation with high accuracy, and a sequence of auxiliary variables are utilized to avoid the high-order derivatives in the absorbing boundary conditions. Then the original problem on unbounded domain is replaced by an equivalent initial boundary value problem defined on a finite domain. The finite difference method is applied to solve the reduced problem on the finite computational domain. Finally, numerical results are presented to demonstrate the effectiveness and accuracy of the proposed method.
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Recombinant Human Erythropoietin Improves the Neurofunctional Recovery of Rats Following Traumatic Brain Injury via an Increase in Circulating Endothelial Progenitor Cells.
Transl Stroke Res
PUBLISHED: 05-04-2014
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Previous studies show that circulating endothelial progenitor cells (EPCs) promote angiogenesis, which is a process associated with improved recovery in animal models of traumatic brain injury (TBI), and that recombinant human erythropoietin (rhEPO) plays a protective role following stroke. Thus, it was hypothesized that rhEPO would enhance recovery following brain injury in a rat model of TBI via an increase in the mobilization of EPCs and, subsequently, in angiogenesis. Flow cytometry assays using CD34- and CD133-specific antibodies were utilized to identify alterations in EPC levels, CD31 and CD34 antibody-stained brain tissue sections were used to quantify angiogenesis, and the Morris water maze (MWM) test and the modified Neurological Severity Score (mNSS) test were used to evaluate behavioral recovery. Compared with saline treatment, treatment with rhEPO significantly increased the number of circulating EPCs on days 1, 4, 7, and 14 (P?
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Plasmonic imaging of protein interactions with single bacterial cells.
Biosens Bioelectron
PUBLISHED: 04-28-2014
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Quantifying the interactions of bacteria with external ligands is fundamental to the understanding of pathogenesis, antibiotic resistance, immune evasion, and mechanism of antimicrobial action. Due to inherent cell-to-cell heterogeneity in a microbial population, each bacterium interacts differently with its environment. This large variability is washed out in bulk assays, and there is a need of techniques that can quantify interactions of bacteria with ligands at the single bacterium level. In this work, we present a label-free and real-time plasmonic imaging technique to measure the binding kinetics of ligand interactions with single bacteria, and perform statistical analysis of the heterogeneity. Using the technique, we have studied interactions of antibodies with single Escherichia coli O157:H7 cells and demonstrated a capability of determining the binding kinetic constants of single live bacteria with ligands, and quantify heterogeneity in a microbial population.
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Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve.
Neural Regen Res
PUBLISHED: 04-25-2014
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Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, but cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhesion stage. Moreover, seeded cells were distributed throughout the material.
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Occurrence, removal, and fate of progestogens, androgens, estrogens, and phenols in six sewage treatment plants around Dianchi Lake in China.
Environ Sci Pollut Res Int
PUBLISHED: 04-25-2014
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The occurrence and behavior of endocrine disrupting chemicals (EDCs) in sewage treatment plants (STPs), especially estrogens and phenols, have been closely concerned in previous studies. However, the systematical researches about progestogens and androgens were scarce in STPs adopting different treatment technologies. This work investigated the occurrence, removal, and fate of one progestogen, three androgens, four estrogens, and six phenols in six STPs around Dianchi Lake in China, where the influents, effluents of primary treatment, secondary treatment, and advanced treatment, as well as excess sludge samples, were analyzed. All of the above EDCs were detected out in influents of the six STPs. Bisphenol A, nonylphenol-mono-ethoxylate, and nonylphenol-diethoxylate were the dominant EDCs detected in those influent samples with the concentrations that varied from 637.6 to 1,684.0 ng/L, 633.8 to 1,540.0 ng/L, and 648.7 to 2,246.0 ng/L, respectively; E1 and dihydrotestosterone were the major steroids with the mean concentration of 126.8 and 277.4 ng/L. For effluents and sludges, phenols showed higher concentration (366.8-1,233.0 ng/L and 1,478.1-6,948.9 ng/g dry weight (dw)) and detection rate (100 %). The total removal rates were more than 80 % for most compounds in wastewater treatment processes, and high removal efficiency (86-100 %) was found for androgens and progestogens compared with estrogens (75-92 %) and phenols (62-85 %). The secondary treatment processes play significant roles on degrading EDCs, whereas the primary sedimentation has little effects. The treatment capacity of anoxic-anaerobic-anoxic membrane bioreactor and anaerobic/anoxic/oxic technologies was superior to the conventional oxidation ditch in the degradation of EDCs. The advanced treatment process, two units of filter (D-type or V-type), and ultraviolet disinfection were adopted and presented effective to remove these compounds. According to fate analysis, it was obvious that biological degradation was the main pathway on the removal of EDCs in STPs compared with adsorption. Risk quotients were calculated to assess ecological risks of those EDCs. Risk quotients of 54 and 61 % were more than 1 in effluents and sludges, respectively, showing potential hazard of effluents and sludges to the environment.
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PCR for detection of oseltamivir resistance mutation in influenza A(H7N9) virus.
Emerging Infect. Dis.
PUBLISHED: 04-23-2014
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Sensitive molecular techniques are needed for rapid detection of the R292K oseltamivir-resistant mutant of influenza A(H7/N9) virus strain to monitor its transmission and guide antiviral treatment. We developed a real-time reverse transcription PCR and single nucleotide polymorphism probes to differentiate this mutant strain in mixed virus populations in human specimens.
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A positive feedback loop involving Erk5 and Akt turns on mesangial cell proliferation in response to PDGF.
Am. J. Physiol., Cell Physiol.
PUBLISHED: 04-16-2014
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Platelet-derived growth factor BB and its receptor (PDGFR?) play a pivotal role in the development of renal glomerular mesangial cells. Their roles in increased mesangial cell proliferation during mesangioproliferative glomerulonephritis have long been noted, but the operating logic of signaling mechanisms regulating these changes remains poorly understood. We examined the role of a recently identified MAPK, Erk5, in this process. PDGF increased the activating phosphorylation of Erk5 and tyrosine phosphorylation of proteins in a time-dependent manner. A pharmacologic inhibitor of Erk5, XMD8-92, abrogated PDGF-induced DNA synthesis and mesangial cell proliferation. Similarly, expression of dominant negative Erk5 or siRNAs against Erk5 blocked PDGF-stimulated DNA synthesis and proliferation. Inhibition of Erk5 attenuated expression of cyclin D1 mRNA and protein, resulting in suppression of CDK4-mediated phosphorylation of the tumor suppressor protein pRb. Expression of cyclin D1 or CDK4 prevented the dominant negative Erk5- or siErk5-mediated inhibition of DNA synthesis and mesangial cell proliferation induced by PDGF. We have previously shown that phosphatidylinositol 3-kinase (PI3-kinase) contributes to PDGF-induced proliferation of mesangial cells. Inhibition of PI3-kinase blocked PDGF-induced phosphorylation of Erk5. Since PI3-kinase acts through Akt, we determined the role of Erk5 on Akt phosphorylation. XMD8-92, dominant negative Erk5, and siErk5 inhibited phosphorylation of Akt by PDGF. Interestingly, we found inhibition of PDGF-induced Erk5 phosphorylation by a pharmacological inhibitor of Akt kinase and kinase dead Akt in mesangial cells. Thus our data unfold the presence of a positive feedback microcircuit between Erk5 and Akt downstream of PI3-kinase nodal point for PDGF-induced mesangial cell proliferation.
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The 19S Deubiquitinase inhibitor b-AP15 is enriched in cells and elicits rapid commitment to cell death.
Mol. Pharmacol.
PUBLISHED: 04-08-2014
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b-AP15 [(3E,5E)-3,5-bis[(4-nitrophenyl)methylidene]-1-(prop-2-enoyl)piperidin-4-one] is a small molecule inhibitor of the ubiquitin specific peptidase (USP) 14/ubiquitin carboxyl-terminal hydrolase (UCH) L5 deubiquitinases of the 19S proteasome that shows antitumor activity in a number of tumor models, including multiple myeloma. b-AP15 contains an ?,?-unsaturated carbonyl unit that is likely to react with intracellular nucleophiles such as cysteine thiolates by Michael addition. We found that binding of b-AP15 to USP14 is partially reversible, and that inhibition of proteasome function is reversible in cells. Despite reversible binding, tumor cells are rapidly committed to apoptosis/cell death after exposure to b-AP15. We show that b-AP15 is rapidly taken up from the medium and enriched in cells. Enrichment provides an explanation of the stronger potency of the compound in cellular assays compared with in vitro biochemical assays. Cellular uptake was impaired by 30-minute pretreatment of cells with low concentrations of N-ethylmaleimide (10 µM), suggesting that enrichment was thiol dependent. We report that in addition to inhibition of deubiquitinases, b-AP15 inhibits the selenoprotein thioredoxin reductase (TrxR). Whereas proteasome inhibition was closely associated with cell death induction, inhibition of TrxR was not. TrxR inhibition is, however, likely to contribute to triggering of oxidative stress observed with b-AP15. Furthermore, we present structure-activity, in vivo pharmacokinetic, and hepatocyte metabolism data for b-AP15. We conclude that the strong enrichment of b-AP15 in cells and a rapid commitment to apoptosis/cell death are factors that likely contribute to the strong antitumor activity of this compound.
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Determination of fungicides in fruit juice by ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of floating organic solvent droplets followed by high performance liquid chromatography.
J AOAC Int
PUBLISHED: 03-29-2014
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Ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) based on solidification of the floating organic solvent droplets (SFO) combined with HPLC was used for determination of five fungicides in fruit juice samples. 1-Dodecanol, which has a low density and low toxicity, was used as the extraction solvent in UA-DLLME. The solidification of floating organic droplets facilitates the transfer of analytes from the aqueous phase to the organic phase. This method was easy, quick, inexpensive, precise, and linear over a wide range. Under the optimized conditions, the enrichment factors for a 5 mL fruit juice sample were 25 to 56, and the LODs for the five fungicides ranged from 5 to 50 microg/L. The average recoveries ranged from 71.8 to 118.2% with RSDs of 0.9 to 13.9%. Application of the DLLME-SFO technique allows successful separation and preconcentration of the fungicides at a low concentration level in fruit juice samples.
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Extraction and in vitro antioxidant activity of exopolysaccharide by Pleurotus eryngii SI-02.
Braz. J. Microbiol.
PUBLISHED: 03-10-2014
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The extraction parameters for Pleurotus eryngii SI-02 exopolysaccharide (EPS) produced during submerged culture were optimized using response surface methodology (RSM). The optimum conditions for EPS extraction were predicted to be, precipitation time 20.24 h, ethanol concentration 89.62% and pH 8.17, and EPS production was estimated at 7.27 g/L. The actual yield of EPS under these conditions was 7.21 g/L. The in vitro antioxidant results of the EPS showed that the inhibition effects of EPS at a dosage of 400 mg/L on hydroxyl, superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were 59.63 ± 3.72%, 38.69 ± 2.59%, and 66.36 ± 4.42%, respectively, which were 12.74 ± 1.03%, 8.01 ± 0.56%, and 12.19 ± 1.05% higher than that of butylated hydroxytoluene (BHT), respectively. The reducing power of EPS of P. eryngii SI-02 was 0.98 ± 0.05, 60.66 ± 5.14% higher than that of BHT. The results provide a reference for large-scale production of EPS by P. eryngii SI-02 in industrial fermentation and the EPS can be used as a potential antioxidant which enhances adaptive immune responses.
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Plasmonic imaging and detection of single DNA molecules.
ACS Nano
PUBLISHED: 03-07-2014
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The capability of imaging and detecting single DNA molecules is critical in the study, analysis, and applications of DNA. Fluorescence imaging is a widely used method, but it suffers from blinking and photobleaching, and fluorescence tags may block or affect binding sites on DNA. We report on label-free imaging of single DNA molecules with a differential plasmonic imaging technique. The technique produces high contrast images due to the scattering of surface plasmonic waves by the molecules and the removal of background noises and interference patterns, allowing for quantitative analysis of individual DNA molecules. Simulation of the images based on a scattering model shows good agreement with the experiment. We further demonstrate optical mapping of single DNA molecules.
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Structural insights into Noonan/LEOPARD syndrome-related mutants of protein-tyrosine phosphatase SHP2 (PTPN11).
BMC Struct. Biol.
PUBLISHED: 03-06-2014
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The ubiquitous non-receptor protein tyrosine phosphatase SHP2 (encoded by PTPN11) plays a key role in RAS/ERK signaling downstream of most, if not all growth factors, cytokines and integrins, although its major substrates remain controversial. Mutations in PTPN11 lead to several distinct human diseases. Germ-line PTPN11 mutations cause about 50% of Noonan Syndrome (NS), which is among the most common autosomal dominant disorders. LEOPARD Syndrome (LS) is an acronym for its major syndromic manifestations: multiple Lentigines, Electrocardiographic abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormalities of genitalia, Retardation of growth, and sensorineural Deafness. Frequently, LS patients have hypertrophic cardiomyopathy, and they might also have an increased risk of neuroblastoma (NS) and acute myeloid leukemia (AML). Consistent with the distinct pathogenesis of NS and LS, different types of PTPN11 mutations cause these disorders.
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Loop-mediated isothermal amplification assays for detecting Yersinia pseudotuberculosis in milk powders.
J. Food Sci.
PUBLISHED: 02-26-2014
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Yersinia pseudotuberculosis is a Gram-negative foodborne pathogen that causes several diseases, such as enteritis, septicemia, and reactive arthritis. Loop-mediated isothermal amplification (LAMP) assay targeting the 16S-23S rDNA internal transcribed spacer (ITS) region was developed to detect Y. pseudotuberculosis in milk powder. The DNA amplification could be completed in 1 h, and detected by produced white precipitate visible to naked eyes. The detection limit of LAMP assay was 10(0) fg/reaction for genomic DNA, and 10(0) CFU/100 g milk powder coupled with 12 h enrichment. LAMP assay is 100 times more sensitive than conventional polymerase chain reaction method for detecting Y. pseudotuberculosis, and correctly identified 18 cases of Y. pseudotuberculosis contaminations from 236 commercial milk powder products. In conclusion, the developed LAMP assay may facilitate rapid detection of Y. pseudotuberculosis contaminations in agricultural and food products.
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Comparative genomics of Brassicaceae crops.
Breed. Sci.
PUBLISHED: 02-16-2014
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The family Brassicaceae is one of the major groups of the plant kingdom and comprises diverse species of great economic, agronomic and scientific importance, including the model plant Arabidopsis. The sequencing of the Arabidopsis genome has revolutionized our knowledge in the field of plant biology and provides a foundation in genomics and comparative biology. Genomic resources have been utilized in Brassica for diversity analyses, construction of genetic maps and identification of agronomic traits. In Brassicaceae, comparative sequence analysis across the species has been utilized to understand genome structure, evolution and the detection of conserved genomic segments. In this review, we focus on the progress made in genetic resource development, genome sequencing and comparative mapping in Brassica and related species. The utilization of genomic resources and next-generation sequencing approaches in improvement of Brassica crops is also discussed.
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USP21 negatively regulates antiviral response by acting as a RIG-I deubiquitinase.
J. Exp. Med.
PUBLISHED: 02-03-2014
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Lys63-linked polyubiquitination of RIG-I is essential in antiviral immune defense, yet the molecular mechanism that negatively regulates this critical step is poorly understood. Here, we report that USP21 acts as a novel negative regulator in antiviral responses through its ability to bind to and deubiquitinate RIG-I. Overexpression of USP21 inhibited RNA virus-induced RIG-I polyubiquitination and RIG-I-mediated interferon (IFN) signaling, whereas deletion of USP21 resulted in elevated RIG-I polyubiquitination, IRF3 phosphorylation, IFN-?/? production, and antiviral responses in MEFs in response to RNA virus infection. USP21 also restricted antiviral responses in peritoneal macrophages (PMs) and bone marrow-derived dendritic cells (BMDCs). USP21-deficient mice spontaneously developed splenomegaly and were more resistant to VSV infection with elevated production of IFNs. Chimeric mice with USP21-deficient hematopoietic cells developed virus-induced splenomegaly and were more resistant to VSV infection. Functional comparison of three deubiquitinases (USP21, A20, and CYLD) demonstrated that USP21 acts as a bona fide RIG-I deubiquitinase to down-regulate antiviral response independent of the A20 ubiquitin-editing complex. Our studies identify a previously unrecognized role for USP21 in the negative regulation of antiviral response through deubiquitinating RIG-I.
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Biliary Excretion of Glycyrrhetinic Acid: Glucuronide-Conjugate Determination Following a Pharmacokinetic Study of Rat Bile.
Phytother Res
PUBLISHED: 01-29-2014
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Liquorice is a commonly prescribed herb in traditional Chinese medicine with the primary constituent, glycyrrhetinic acid (GA) responsible for the toxic effects arising from its chronic consumption. Hepatic transformation and biliary excretion of GA are significant and well-documented pharmacokinetic pathways in humans, while glucuronide conjugates are the major identified metabolites. Here we report the role of bile in GA bioconversion in rats; this being achieved following intravenous administration of GA to Sprague-Dawley rats at a dose of 2?mg/kg with bile fluid analyzed for 3?h post-injection using HPLC. The maximum concentration of glucuronides was detected about 30?min post-administration, while the cumulative biliary excretion of glucuronides after 3?h was found to be 63.6?±?6.4%. Our findings indicate a relatively high rate of biliary excretion for GA via the formation of glucuronide conjugates, and as a result of these findings, glucuronidation can be firmly regarded as a primary detoxification pathway for GA in rats. Copyright © 2014 John Wiley & Sons, Ltd.
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Induction of mitochondrial dysfunction as a strategy for targeting tumour cells in metabolically compromised microenvironments.
Nat Commun
PUBLISHED: 01-21-2014
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Abnormal vascularization of solid tumours results in the development of microenvironments deprived of oxygen and nutrients that harbour slowly growing and metabolically stressed cells. Such cells display enhanced resistance to standard chemotherapeutic agents and repopulate tumours after therapy. Here we identify the small molecule VLX600 as a drug that is preferentially active against quiescent cells in colon cancer 3-D microtissues. The anticancer activity is associated with reduced mitochondrial respiration, leading to bioenergetic catastrophe and tumour cell death. VLX600 shows enhanced cytotoxic activity under conditions of nutrient starvation. Importantly, VLX600 displays tumour growth inhibition in vivo. Our findings suggest that tumour cells in metabolically compromised microenvironments have a limited ability to respond to decreased mitochondrial function, and suggest a strategy for targeting the quiescent populations of tumour cells for improved cancer treatment.
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Assessment of toxic effects of triclosan on the terrestrial snail (Achatina fulica).
Chemosphere
PUBLISHED: 01-05-2014
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Triclosan (TCS) is a broad-spectrum antimicrobial agent used in personal care products, and as a result, is widespread in the environment. Toxicity tests of TCS on aquatic organisms have been reported, but limited toxicity data on terrestrial species are available. In this study, the 28-d chronic toxicity of TCS on the biomass, shell diameter growth, and total food intake of the terrestrial snail Achatina fulica were tested. Moreover, biochemical responses, including changes in the activity of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and the content of malondialdehyde (MDA), were examined after 14-d and 28-d exposure. Results showed that TCS had toxic effects on the biomass, shell diameter growth, and total food intake of A. fulica with no observed effect concentration (NOEC) values of 24 mg kg(-1). As for the antioxidant enzymes, TCS caused significant oxidative stress even at the low concentration of 24 mg kg(-1). The CAT and POD activities at the high concentrations of 200 and 340 mg kg(-1), respectively, were significantly inhibited. The SOD and CAT activity in treatments below 118 mg kg(-1) and the MDA content in all treatments showed dose-effect relationships. This study demonstrated that TCS caused adverse effects on terrestrial invertebrates, and provided valuable information for the risk assessment imposed by TCS in the terrestrial environment.
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Analysis on tank truck accidents involved in road hazardous materials transportation in china.
Traffic Inj Prev
PUBLISHED: 01-02-2014
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Due to the sheer size and capacity of the tanker and the properties of cargo transported in the tank, hazmat tanker accidents are more disastrous than other types of vehicle accidents. The aim of this study was to provide a current survey on the situation of accidents involving tankers transporting hazardous materials in China.
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Elevation of peripheral BDNF promoter methylation links to the risk of Alzheimer's disease.
PLoS ONE
PUBLISHED: 01-01-2014
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Brain derived neurotrophic factor (BDNF) has been known to play an important role in various mental disorders or diseases such as Alzheimer's disease (AD). The aim of our study was to assess whether BDNF promoter methylation in peripheral blood was able to predict the risk of AD. A total of 44 AD patients and 62 age- and gender-matched controls were recruited in the current case-control study. Using the bisulphite pyrosequencing technology, we evaluated four CpG sites in the promoter of the BDNF. Our results showed that BDNF methylation was significantly higher in AD cases than in the controls (CpG1: p?=?10.021; CpG2: p?=?0.002; CpG3: p?=?0.007; CpG4: p?=?0.005; average methylation: p?=?0.004). In addition, BDNF promoter methylation was shown to be significantly correlated with the levels of alkaline phosphatase (ALP), glucose, Lp(a), ApoE and ApoA in males (ALP: r?=?-0.308, p?=?0.042; glucose: r?=?-0.383, p?=?0.010; Lp(a): r?=?0.333, p?=?0.027; ApoE: r?=?-0.345, p?=?0.032;), ApoA levels in females (r?=?0.362, p?=?0.033), and C Reactive Protein (CRP) levels in both genders (males: r?=?-0.373, p?=?0.016; females: r?=?-0.399, p?=?0.021). Our work suggested that peripheral BDNF promoter methylation might be a diagnostic marker of AD risk, although its underlying function remains to be elaborated in the future.
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Electrospun fibrous scaffolds combined with nanoscale hydroxyapatite induce osteogenic differentiation of human periodontal ligament cells.
Int J Nanomedicine
PUBLISHED: 01-01-2014
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Periodontal repair is a complex process in which regeneration of alveolar bone is a vital component. The aim of this study was to develop a biodegradable scaffold with good biocompatibility and osteoinductive ability. Two types of composite fibrous scaffolds were produced by electrospinning, ie, type I collagen/poly(?-caprolactone) (COL/PCL) and type I collagen/poly(?-caprolactone)/nanoscale hydroxyapatite (COL/PCL/nHA) with an average fiber diameter of about 377 nm. After a simulated body fluid (SBF) immersion test, the COL/PCL/nHA-SBF scaffold developed a rough surface because of the calcium phosphate deposited on the fibers, suggesting that the presence of nHA promoted the mineralization potential of the scaffold. Energy dispersive X-ray spectroscopy clearly showed the calcium and phosphorus content in the COL/PCL/nHA and COL/PCL/nHA-SBF scaffolds, confirming the findings of nHA and calcium phosphate precipitation on scanning electron micrographs. Water contact analysis revealed that nHA could improve the hydrophilic nature of the COL/PCL/nHA-SBF scaffold. The morphology of periodontal ligament cells cultured on COL/PCL-SBF and COL/PCL/nHA-SBF was evaluated by scanning electron microscopy. The results showed that cells adhered to either type of scaffold and were slightly spindle-shaped in the beginning, then extended gradually with stretched filopodia, indicating an ability to fill the fiber pores. A Cell Counting Kit-8 assay showed that both scaffolds supported cell proliferation. However, real-time quantitative polymerase chain reaction analysis showed that expression of the bone-related markers, alkaline phosphatase and osteocalcin, was upregulated only on the COL/PCL/nHA-SBF scaffold, indicating that this scaffold had the ability to induce osteogenic differentiation of periodontal ligament cells. In this study, COL/PCL/nHA-SBF produced by electrospinning followed by biomimetic mineralization had combined electrospun fibers with nHA in it. This scaffold has good biocompatibility and osteoinductive ability as a result of the characteristics of nHA, so could be innovatively applied to periodontal tissue engineering as a potential scaffold.
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Comparison of circulating, hepatocyte specific messenger RNA and microRNA as biomarkers for chronic hepatitis B and C.
PLoS ONE
PUBLISHED: 01-01-2014
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Circulating microRNAs have been widely recognized as a novel category of biomarker in a variety of physiological and pathological conditions. Other reports revealed that fragments of organ specific messenger RNAs are also detectable in serum/plasma and can be utilized as sensitive indicators of liver pathology and cancer. In order to assess the sensitivity and reliability of these two class of RNAs as marker of hepatitis B or C induced chronic liver disease, we collected plasma samples from 156 chronic hepatitis B or C patients (HBV active n?=?112, HBV carrier n?=?19, hepatitis C n?=?25) and 22 healthy donors and quantified their circulating mRNA for albumin, HP (haptoglobin), CYP2E1 (cytochrome P450, family 2, subfamily E) and ApoA2 (Apolipoprotein A2) in conjunction with microRNA-122, a well established marker for acute and chronic liver injury. We found that plasma microRNA-122 level is significantly elevated in patients with active HBV but not in HBV carriers. Furthermore, microRNA-122 is not elevated in HCV patients even though their median serum alanine aminotransferase (sALT) was three fold of the healthy donors. Nevertheless, circulating mRNAs, especially albumin mRNA, showed much more sensitivity in distinguishing active hepatitis B, hepatitis B carrier or HCV patients from healthy control. Correlation and multiple linear regression analysis suggested that circulating mRNAs and miRNAs are much more related to HBsAg titre than to sALT. Immunoprecipitation of HBsAg in HBV patients' plasma resulted in enrichment of albumin and HP mRNA suggesting that fragments of liver specific transcripts can be encapsidated into HBsAg particles. Taken together, our results suggest that hepatocyte specific transcripts in plasma like albumin mRNA showed greater sensitivity and specificity in differentiating HBV or HCV induced chronic liver disease than microRNA-122. Circulating mRNA fragments merit more attention in the quest of next generation biomarkers for various maladies.
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[Preparation and characterization of the recombinant hFGF21-containing lentiviral].
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi
PUBLISHED: 12-11-2013
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To package the lentiviral particles carrying human fibroblast growth factor 21 (hFGF21) and identify the morphological characteristics and transduction capability for the target gene of human embryo kidney 293T (HEK293T) cells.
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Investigating Cronobacter sakazakii responses to garlic-derived organosulfur compounds: a systematic study of pathogenic bacteria injury using high-throughput whole transcriptome sequencing and confocal micro-Raman spectroscopy.
Appl. Environ. Microbiol.
PUBLISHED: 11-22-2013
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We present the study using high-throughput whole transcriptome sequencing (RNA-seq) and vibrational spectroscopy to characterize and fingerprint pathogenic bacteria injury under unfavorable stress. Two garlic-derived organosulfur compounds were found to be highly effective antimicrobial compounds against Cronobacter sakazakii, a leading pathogen associated with invasive infection of infants causing meningitis, necrotizing entercolitis and bacteraemia. RNA-seq shows changes in gene expression patterns and transcriptomic response while confocal micro-Raman spectroscopy characterizes macromolecular changes in bacterial cell resulting from this chemical stress. RNA-seq analyses showed that the bacterial response to ajoene differed from diallyl sulfide. Specifically ajoene caused down regulation of motility related genes, while diallyl sulfide treatment caused an increased expression of cell wall synthesis genes. Confocal micro-Raman spectroscopy revealed that both compounds appear to have the same phase I antimicrobial mechanism of binding to thiol-containing proteins/enzymes in bacterial cells generating a disulfide stretching band, but a different phase II showing alterations in the secondary structures of proteins in two different ways. Diallyl sulfide primarily altered ?-helix and ?-sheet as reflected in changes in amide I while ajoene altered the structures containing phenylalanine and tyrosine. Bayesian probability validated the ability of principal component analysis to differentiate treated and control C. sakazakii cells. Scanning electron microscopy confirmed cell injury showing significant morphological variations in cells following treatments by these two compounds. Findings from this study aid in the development of effective intervention strategies to reduce the risk of C. sakazakii contamination in food production environment and food contact surfaces, reducing the risks to susceptible consumers.
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Use of the dye stain assay and ultraviolet light test for assessing vaginal insertion of placebo-filled applicators before and after sex.
Sex Transm Dis
PUBLISHED: 11-14-2013
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Applicator dye staining and ultraviolet (UV) light have been used in trials to measure adherence, but not in the setting of before and after sex gel dosing (BAT-24). This study was designed to determine if semen or presex gel dosing impacts the sensitivity and specificity of a dye stain assay (DSA) for measuring vaginal insertion of placebo-filled applicators with BAT-24 dosing.
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Role of local versus systemic vitamin d receptors in vascular calcification.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 11-07-2013
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Calcitriol and various analogs are commonly used to suppress secondary hyperparathyroidism in chronic kidney disease but may also exacerbate vascular calcification. Although this could be because of increased intestinal calcium and phosphate absorption, direct effects through vitamin D receptors (VDRs) on vascular smooth muscle have also been proposed.
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Unraveling a three-step spatiotemporal mechanism of triggering of receptor-induced nipah virus fusion and cell entry.
PLoS Pathog.
PUBLISHED: 11-01-2013
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Membrane fusion is essential for entry of the biomedically-important paramyxoviruses into their host cells (viral-cell fusion), and for syncytia formation (cell-cell fusion), often induced by paramyxoviral infections [e.g. those of the deadly Nipah virus (NiV)]. For most paramyxoviruses, membrane fusion requires two viral glycoproteins. Upon receptor binding, the attachment glycoprotein (HN/H/G) triggers the fusion glycoprotein (F) to undergo conformational changes that merge viral and/or cell membranes. However, a significant knowledge gap remains on how HN/H/G couples cell receptor binding to F-triggering. Via interdisciplinary approaches we report the first comprehensive mechanism of NiV membrane fusion triggering, involving three spatiotemporally sequential cell receptor-induced conformational steps in NiV-G: two in the head and one in the stalk. Interestingly, a headless NiV-G mutant was able to trigger NiV-F, and the two head conformational steps were required for the exposure of the stalk domain. Moreover, the headless NiV-G prematurely triggered NiV-F on virions, indicating that the NiV-G head prevents premature triggering of NiV-F on virions by concealing a F-triggering stalk domain until the correct time and place: receptor-binding. Based on these and recent paramyxovirus findings, we present a comprehensive and fundamentally conserved mechanistic model of paramyxovirus membrane fusion triggering and cell entry.
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Determination of ?-tocopherol in vegetable oils using a molecularly imprinted polymers-surface-enhanced Raman spectroscopic biosensor.
J. Agric. Food Chem.
PUBLISHED: 10-22-2013
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We report the development of a novel hybrid "capture-detection" molecularly imprinted polymers-surface-enhanced Raman spectroscopic (MIPs-SERS) biosensor for the detection and quantification of ?-tocopherol (?-Toc) in vegetable oils. ?-Toc served as the template for MIPs synthesis. Methacrylic acid formed as the functional monomer. Ethylene glycol dimethacrylate was the cross-linking agent, and 2,2-azobisisobutyronitrile was used as the initiator. The synthesized MIPs functioned to rapidly and selectively adsorb and separate ?-Toc from oil components. We validated a dendritic silver nanostructure synthesized by a displacement reaction to be a suitable SERS substrate for the enhancement of Raman signals. Second-derivative transformations and chemometric models based upon SERS spectral features confirmed the possibility of a rapid and precise detection and quantification of different spiking levels of ?-Toc in four different sources of vegetable oils (Mahalanobis distance from 15.93 to 34.01 for PCA model; R > 0.92, RMSE < 0.41 for PLSR model). The MIPs-SERS biosensor had a high sensitivity as well as a good recovery for ?-Toc analysis in vegetable oils. The entire analysis required 15 min or less to complete with limited sample preparation.
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Induction of Tumor Cell Apoptosis by a Proteasome Deubiquitinase Inhibitor Is Associated with Oxidative Stress.
Antioxid. Redox Signal.
PUBLISHED: 09-10-2013
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Abstract Aims: b-AP15 is a recently described inhibitor of the USP14/UCHL5 deubiquitinases (DUBs) of the 19S proteasome. Exposure to b-AP15 results in blocking of proteasome function and accumulation of polyubiquitinated protein substrates in cells. This novel mechanism of proteasome inhibition may potentially be exploited for cancer therapy, in particular for treatment of malignancies resistant to currently used proteasome inhibitors. The aim of the present study was to characterize the cellular response to b-AP15-mediated proteasome DUB inhibition. Results: We report that b-AP15 elicits a similar, but yet distinct, cellular response as the clinically used proteasome inhibitor bortezomib. b-AP15 induces a rapid apoptotic response, associated with enhanced induction of oxidative stress and rapid activation of Jun-N-terminal kinase 1/2 (JNK)/activating protein-1 signaling. Scavenging of reactive oxygen species and pharmacological inhibition of JNK reduced b-AP15-induced apoptosis. We further report that endoplasmic reticulum (ER) stress is induced by b-AP15 and is involved in apoptosis induction. In contrast to bortezomib, ER stress is associated with induction of ?-subunit of eukaryotic initiation factor 2 phosphorylation. Innovation: The findings establish that different modes of proteasome inhibition result in distinct cellular responses, a finding of potential therapeutic importance. Conclusion: Our data show that enhanced oxidative stress and ER stress are major determinants of the strong apoptotic response elicited by the 19S DUB inhibitor b-AP15. Antioxid. Redox Signal. 00, 000-000.
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A one-pot synthesis of reduced graphene oxide-Cu?S quantum dot hybrids for optoelectronic devices.
Nanoscale
PUBLISHED: 08-01-2013
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We demonstrate a facile one-pot approach for the synthesis of reduced graphene oxide (rGO)-cuprous sulfide quantum dot (Cu?S QD) hybrids, wherein the reduction of GO and the growth of Cu?S QDs on graphene occur simultaneously. The as-synthesized rGO-Cu?S QD hybrids exhibit an excellent photoelectric response and efficient electron transfer from the Cu?S QDs to the rGO sheets.
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Charge-based detection of small molecules by plasmonic-based electrochemical impedance microscopy.
Anal. Chem.
PUBLISHED: 07-03-2013
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Charge-based detection of small molecules is demonstrated by plasmonic-based electrochemical impedance microscopy (P-EIM). The dependence of surface plasmon resonance (SPR) on surface charge density is used to detect small molecules (60-120 Da) printed on a dextran-modified sensor surface. Local variations in charge density on an electrode surface are manifest in an optical SPR signal. The SPR response to an applied ac potential measures the sensor surface impedance which is a function of the surface charge density. This optical signal is comprised of a dc and an ac component, and is measured with high spatial resolution. The dc element of the SPR signal represents conventional SPR imaging information. The amplitude and phase of local surface impedance is provided by the ac component. The phase signal of the small molecules is a function of their charge status, which is manipulated by the pH of a solution. Small molecules with positive, neutral, and negative charge are detected by P-EIM. This technique is used to detect and distinguish small molecules based on their charge status, thereby circumventing the mass limitation (~100 Da) of conventional SPR measurement.
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Effective elimination of cancer stem cells by a novel drug combination strategy.
Stem Cells
PUBLISHED: 06-26-2013
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Development of effective therapeutic strategies to eliminate cancer stem cells, which play a major role in drug resistance and disease recurrence, is critical to improve cancer treatment outcomes. Our study showed that glioblastoma stem cells (GSCs) exhibited low mitochondrial respiration and high glycolytic activity. These GSCs were highly resistant to standard drugs such as carmustine and temozolomide (TMZ), but showed high sensitivity to a glycolytic inhibitor 3-bromo-2-oxopropionate-1-propyl ester (3-BrOP), especially under hypoxic conditions. We further showed that combination of 3-BrOP with carmustine but not with TMZ achieved a striking synergistic effect and effectively killed GSCs through a rapid depletion of cellular ATP and inhibition of carmustine-induced DNA repair. This drug combination significantly impaired the sphere-forming ability of GSCs in vitro and tumor formation in vivo, leading to increase in the overall survival of mice bearing orthotopic inoculation of GSCs. Further mechanistic study showed that 3-BrOP and carmustine inhibited glyceraldehyde-3-phosphate dehydrogenase and caused a severe energy crisis in GSCs. Our study suggests that GSCs are highly glycolytic and that certain drug combination strategies can be used to effectively overcome their drug resistance based on their metabolic properties.
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Nutritional risk screening and its clinical significance in hospitalized children.
Clin Nutr
PUBLISHED: 06-14-2013
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To analyse nutritional risk in hospitalized children and its relationship with clinical outcomes to provide evidence for improved nutritional management.
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Strength and fracture behavior of graphene grain boundaries: effects of temperature, inflection, and symmetry from molecular dynamics.
Phys Chem Chem Phys
PUBLISHED: 06-14-2013
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We present a molecular dynamic simulation on the mechanical strength and fracture behavior of graphene grain boundaries (GBs). The intrinsic strength, critical failure strain, and failure mechanism of graphene GBs mainly rely on the temperature and inflection angle, whereas the Youngs modulus does not vary significantly with either temperature or boundary configuration. The overall intrinsic strengths of inflected GBs can be correlated with infection angle by a linear term, which is irrelevant to the system temperature. The initial failure sites of GBs locate either on the boundary line or inside the domain at high temperature.
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Association between adverse clinical outcome in human disease caused by novel influenza A H7N9 virus and sustained viral shedding and emergence of antiviral resistance.
Lancet
PUBLISHED: 05-29-2013
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On March 30, a novel influenza A subtype H7N9 virus (A/H7N9) was detected in patients with severe respiratory disease in eastern China. Virological factors associated with a poor clinical outcome for this virus remain unclear. We quantified the viral load and analysed antiviral resistance mutations in specimens from patients with A/H7N9.
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Parallel pathways for cross-modal memory retrieval in Drosophila.
J. Neurosci.
PUBLISHED: 05-17-2013
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Memory-retrieval processing of cross-modal sensory preconditioning is vital for understanding the plasticity underlying the interactions between modalities. As part of the sensory preconditioning paradigm, it has been hypothesized that the conditioned response to an unreinforced cue depends on the memory of the reinforced cue via a sensory link between the two cues. To test this hypothesis, we studied cross-modal memory-retrieval processing in a genetically tractable model organism, Drosophila melanogaster. By expressing the dominant temperature-sensitive shibire(ts1) (shi(ts1)) transgene, which blocks synaptic vesicle recycling of specific neural subsets with the Gal4/UAS system at the restrictive temperature, we specifically blocked visual and olfactory memory retrieval, either alone or in combination; memory acquisition remained intact for these modalities. Blocking the memory retrieval of the reinforced olfactory cues did not impair the conditioned response to the unreinforced visual cues or vice versa, in contrast to the canonical memory-retrieval processing of sensory preconditioning. In addition, these conditioned responses can be abolished by blocking the memory retrieval of the two modalities simultaneously. In sum, our results indicated that a conditioned response to an unreinforced cue in cross-modal sensory preconditioning can be recalled through parallel pathways.
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Beclin 2 functions in autophagy, degradation of G protein-coupled receptors, and metabolism.
Cell
PUBLISHED: 05-14-2013
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The molecular mechanism of autophagy and its relationship to other lysosomal degradation pathways remain incompletely understood. Here, we identified a previously uncharacterized mammalian-specific protein, Beclin 2, which, like Beclin 1, functions in autophagy and interacts with class III PI3K complex components and Bcl-2. However, Beclin 2, but not Beclin 1, functions in an additional lysosomal degradation pathway. Beclin 2 is required for ligand-induced endolysosomal degradation of several G protein-coupled receptors (GPCRs) through its interaction with GASP1. Beclin 2 homozygous knockout mice have decreased embryonic viability, and heterozygous knockout mice have defective autophagy, increased levels of brain cannabinoid 1 receptor, elevated food intake, and obesity and insulin resistance. Our findings identify Beclin 2 as a converging regulator of autophagy and GPCR turnover and highlight the functional and mechanistic diversity of Beclin family members in autophagy, endolysosomal trafficking, and metabolism.
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The nNOS-p38MAPK pathway is mediated by NOS1AP during neuronal death.
J. Neurosci.
PUBLISHED: 05-10-2013
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Neuronal nitric oxide synthase (nNOS) and p38MAPK are strongly implicated in excitotoxicity, a mechanism common to many neurodegenerative conditions, but the intermediary mechanism is unclear. NOS1AP is encoded by a gene recently associated with sudden cardiac death, diabetes-associated complications, and schizophrenia (Arking et al., 2006; Becker et al., 2008; Brzustowicz, 2008; Lehtinen et al., 2008). Here we find it interacts with p38MAPK-activating kinase MKK3. Excitotoxic stimulus induces recruitment of NOS1AP to nNOS in rat cortical neuron culture. Excitotoxic activation of p38MAPK and subsequent neuronal death are reduced by competing with the nNOS:NOS1AP interaction and by knockdown with NOS1AP-targeting siRNAs. We designed a cell-permeable peptide that competes for the unique PDZ domain of nNOS that interacts with NOS1AP. This peptide inhibits NMDA-induced recruitment of NOS1AP to nNOS and in vivo in rat, doubles surviving tissue in a severe model of neonatal hypoxia-ischemia, a major cause of neonatal death and pediatric disability. The highly unusual sequence specificity of the nNOS:NOS1AP interaction and involvement in excitotoxic signaling may provide future opportunities for generation of neuroprotectants with high specificity.
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Comparison of species sensitivity distributions for species from China and the USA.
Environ Sci Pollut Res Int
PUBLISHED: 05-02-2013
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China has recently commenced water quality criteria (WQC) research using the species sensitivity distribution (SSD) method; however, it is difficult to obtain sufficient native species toxicity data for thousands of contaminants. In this study, the feasibility of using non-native toxicity data in deriving native WQC was analyzed. We constructed SSDs based on acute toxicity data of species from China and the USA for eight priority pollutants, and compared the sensitivities of different taxonomic groups between the two countries. The results showed that the SSD method of log-logistic distribution fit the toxicity data of different taxa well. The comparison of sensitivity distribution and hazardous concentration for 5 % of the species and 50 % of the species showed that there was no significant difference between Chinese and American taxa. It could be feasible to use toxicity data from the USA to provide a temporary way to protect organisms in China in emergency situations or for management of priority pollutants when native toxicity data are lacking.
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Hepatitis B virus polymerase impairs interferon-?-induced STA T activation through inhibition of importin-?5 and protein kinase C-?.
Hepatology
PUBLISHED: 04-05-2013
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Treatment with exogenous interferon (IFN)-? is not effective in the majority of patients with chronic hepatitis B virus (HBV) infection. Recent evidence suggests that HBV has evolved strategies to block the nuclear translocation of signal transducer and activator of transcription (STAT) 1 to limit IFN-?-induced cellular antiviral responses. However, it remains unclear whether STAT1 translocation is impaired in chronic hepatitis B patients and what mechanisms are involved. Here we report that the expression of HBV polymerase (Pol) in human hepatic cell lines inhibited induction of IFN-stimulated genes and resulted in a weakened antiviral activity of IFN-?. Ectopic expression of Pol suppressed IFN-?-induced STAT1 serine 727 phosphorylation and STAT1/2 nuclear accumulation, whereas STAT1 tyrosine 701 phosphorylation, and STAT1-STAT2 heterodimer formation were not affected. Further studies demonstrated that Pol interacted with the catalytic domain of protein kinase C-? (PKC-?) and perturbed PKC-? phosphorylation and its association with STAT1, which resulted in the suppression of STAT1 Ser727 phosphorylation. Moreover, Pol was found to interfere with nuclear transportation of STAT1/2 by competitively binding to the region of importin-?5 required for STAT1/2 recruitment. Truncation analysis suggested that the terminal protein and RNase H domains of Pol were able to bind to PKC-? and importin-?5, respectively, and were responsible for the inhibition of IFN-? signaling. More importantly, the inhibition of STAT1 and PKC-? phosphorylation were confirmed in a hydrodynamic-based HBV mouse model, and the blockage of IFN-?-induced STAT1/2 nuclear translocation was observed in HBV-infected cells from liver biopsies of chronic HBV patients.
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Assessment of the ecological security of immobilized enzyme remediation process with biological indicators of soil health.
Environ Sci Pollut Res Int
PUBLISHED: 03-07-2013
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This study used the enzymes extracted from an atrazine-degrading strain, Arthrobacter sp. DNS10, which had been immobilized by sodium alginate to rehabilitate atrazine-polluted soil. Meanwhile, a range of biological indices were selected to assess the ecological health of contaminated soils and the ecological security of this bioremediation method. The results showed that there was no atrazine detected in soil samples after 28 days in EN+AT (the soil containing atrazine and immobilized enzyme) treatment. However, the residual atrazine concentration of the sample in AT (the soil containing atrazine only) treatment was about 5.02 ± 0.93 mg kg(-1). These results suggest that the immobilized enzyme exhibits an excellent ability in atrazine degradation. Furthermore, the immobilized enzyme could relieve soil microbial biomass carbon and soil microbial respiration intensity to 772.33 ± 34.93 mg C kg(-1) and 5.01 ± 0.17 mg CO(2) g(-1) soil h(-1), respectively. The results of the polymerase chain reaction-degeneration gradient gel electrophoresis experiment indicated that the immobilized enzyme also could make the Shannon-Wiener index and evenness index of the soil sample increase from 1.02 and 0.74 to 1.51 and 0.84, respectively. These results indicated that the immobilized enzymes not only could relieve the impact from atrazine on the soil, but also revealed that the immobilized enzymes did no significant harm on the soil ecological health.
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Identical versus conceptual repetition FN400 and parietal old/new ERP components occur during encoding and predict subsequent memory.
Brain Res.
PUBLISHED: 02-25-2013
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This Event-Related Potential (ERP) study investigated whether components commonly measured at test, such as the FN400 and the parietal old/new components, could be observed during encoding and, if so, whether they would predict different levels of accuracy on a subsequent memory test. ERPs were recorded while subjects classified pictures of objects as man-made or natural. Some objects were only classified once, while others were classified twice during encoding, sometimes with an identical picture, and other times with a different exemplar from the same category. A subsequent surprise recognition test required subjects to judge whether each probe word corresponded to a picture shown earlier, and if so whether there were two identical pictures that corresponded to the word probe, two different pictures, or just one picture. When the second presentation showed a duplicate of an earlier picture, the FN400 effect (a significantly less negative deflection on the second presentation) was observed regardless of subsequent memory response; however, when the second presentation showed a different exemplar of the same concept, the FN400 effect was only marginally significant. In contrast, the parietal old/new effect was robust for the second presentation of conceptual repetitions when the test probe was subsequently recognized, but not for identical repetitions. These findings suggest that ERP components that are typically observed during an episodic memory test can be observed during an incidental encoding task, and that they are predictive of the degree of subsequent memory performance.
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Development and validation of a simple, sensitive and accurate LC-MS/MS method for the determination of guanfacine, a selective ?2A -adrenergicreceptor agonist, in plasma and its application to a pharmacokinetic study.
Biomed. Chromatogr.
PUBLISHED: 02-14-2013
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A simple, practical, accurate and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated for the quantitation of guanfacine in beagle dog plasma. After protein precipitation by acetonitrile, the analytes were separated on a C18 chromatographic column by methanol and water containing 0.1% (v/v) formic acid with a gradient elution. The subsequent detection utilized a mass spectrometry under positive ion mode with multiple reaction monitoring of guanfacine and enalaprilat (internal standard) at m/z 246.2???159.0 and m/z 349.2???205.9, respectively. Good linearity was obtained over the concentration range of 0.1-20?ng/mL for guanfacine in dog plasma and the lower limit of quantification of this method was 0.1?ng/mL. The intra- and inter-day precisions were <10.8% relative standard deviation with an accuracy of 92.9-108.4%. The matrix effects ranged from 89.4 to 100.7% and extraction recoveries were >90%. Stability studies showed that both analytes were stable during sample preparation and analysis. The established method was successfully applied to an in vivo pharmacokinetic study in beagle dogs after a single oral dose of 4?mg guanfacine extended-release tablets. Copyright © 2013 John Wiley & Sons, Ltd.
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Small Molecules Activating TrkB Receptor for Treating a Variety of CNS Disorders.
CNS Neurol Disord Drug Targets
PUBLISHED: 02-08-2013
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The brain-derived neurotrophic factor (BDNF) and its high affinity receptor tropomyosin-receptor-kinase B (TrkB) play a critical role in neuronal differentiation and survival, synapse plasticity, and memory. Indeed, both have been implicated in the pathophysiology of numerous diseases. Although the remarkable therapeutic potential of BDNF has generated much research over the past decade, the poor pharmacokinetics and adverse side effect profile have limited its clinical usefulness of BDNF. Small compounds that mimic BDNFs neurotrophic signaling and overcome the pharmacokinetic and side effect barriers may have greater therapeutic potential. The purpose of this review is to provide a survey of the various strategies taken towards the development of small molecule mimetics for BDNF and the selective TrkB agonist. A particular focus was placed on TrkB agonist 7, 8-dihydroxyflavone, which modulates multiple functions and has demonstrated remarkable therapeutic efficacy in a variety of central nervous system disease models. Two other small molecules included in this review are adenosine A2A receptor agonists that indirectly activate TrkB, and TrkB binding domains of BDNF, loop II-LM22A compounds that directly activate TrkB. These alternative molecules have shown promise in preclinical studies and may be included in prospective clinical investigations.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.