Unresolved airway obstruction in a child secondary to multiple pathologies

Publication date: Available online 28 December 2016
Source:Egyptian Journal of Ear, Nose, Throat and Allied Sciences
Author(s): Pek Ser Heng, Suzina Sheikh Hamid, Abdul Razak Ahmad
In neonates, noisy breathing is one of the common presenting illnesses that require immediate attention and it is always referred to otorhinolaryngology (ORL) team for further assessment. Neonatal stridor can arise from congenital or acquired pathologies at different anatomical sites such as supraglottis, glottis, subglottis and laryngotracheal tree. We report a case of a 5-year-old boy with unresolved airway obstruction since the age of 2weeks old. He presented with progressively worsening of stridor and dyspnea. Emergency tracheostomy was done at neonatal period. He was diagnosed with different airway pathologies at different occasions. Tracheomalacia and laryngomalacia were initially found at neonatal and infantile periods. At later age, a subglottic band was revealed and CO2 laser therapy was employed in treatment.



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Effect of temperature-dependent cross sections on O4 slant column density estimation by a space-borne UV–visible hyperspectral sensor

Publication date: March 2017
Source:Atmospheric Environment, Volume 152
Author(s): Sang Seo Park, Toshihiko Takemura, Jhoon Kim
The sensitivities of oxygen dimer (O4) slant column densities (SCDs) were examined by applying temperature-dependent O4 cross sections using the radiative transfer model (RTM) calculation with the linearized pseudo-spherical vector discrete ordinate radiative transfer model. For the sensitivity study, we used a newly developed cross section database in place of the database used in the operational algorithm. Newly investigated O4 cross section databases for 203 K and 293 K were used for the radiance simulation by interpolating temperature for each atmospheric layer based on the vertical profile of standard atmosphere in the RTM. The effect of the temperature-dependent cross sections was a significant O4 SCD increase of 8.3% with dependence on satellite and solar viewing geometries. Furthermore, the O4 SCD generally increased by an estimated 3.9% based on the observation geometries of the Ozone Monitoring Instrument. For the long-term comparison, the O4 SCD estimated from the temperature-dependent cross sections corrects 20% of the total underestimation of O4 SCD between the observation and simulation. Although the surface pressure variation and background aerosol effect also correct the O4 SCD discrepancy, the effect of temperature-dependent cross sections was more important than the effects of surface pressure variation and background aerosols. Therefore, temperature dependence of the cross section in the RTM calculation is essential for the accurate simulation of O4 SCD.



http://ift.tt/2icts6R

New insights into the parametrization of temperature and light responses of mono - and sesquiterpene emissions from Aleppo pine and rosemary

Publication date: March 2017
Source:Atmospheric Environment, Volume 152
Author(s): M. Staudt, I. Bourgeois, R. Al Halabi, W. Song, J. Williams
Phytogenic emission of large volatile organic compounds (VOCs) such as monoterpenes (MTs) and sesquiterpenes (SQTs) are key precursors to the formation and growth of atmospheric particles. However, controlled environment studies to elucidate emission responses to temperature and light are still sparse. In this study, the volatile contents and emission responses of Aleppo pine and Rosemary have been investigated. These two common Mediterranean species store semivolatiles inside (resin ducts) and outside (trichomes) their foliage tissues respectively. Both species emitted mainly MTs with basal emission rates of around 5 (Rosemary) and 10 (pine) μg g⁻¹ h⁻¹ and SQTs about one order of magnitude lower. In Aleppo pine, two volatile sources could be clearly distinguished: 1) de-novo synthesized emission of (E)-β-ocimene and linalool, which accounted for about 70% of the total VOC release, were not found in foliar VOC extracts and expressed light dependency (LD) and temperature responses typical for enzyme driven emissions; and 2) storage-derived emissions of various MTs and SQTs whose emissions increased exponentially with temperature, showed no light dependency and were all present in leaf extracts. In Rosemary, all emitted MTs and SQTs including many oxygenated compounds, showed responses typical for stored volatiles and were all found in leaf extracts. The emissions of individual volatiles or volatile classes could be well described with the commonly applied empirical algorithms developed for LD or non LD emissions. However, the shapes of the temperature responses, and hence the deduced coefficient values, were significantly different between oxygenated and non-oxygenated compounds. They also differed between the storage-derived emissions of the two plant species, for individual VOCs or VOC classes. We address the possible reasons for this variation in temperature responses and argue that they are mostly due to molecular interactions along the species specific leaf-internal diffusion paths including the build-up of transient VOC pools and degradation.

Graphical abstract

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Impact of future climate policy scenarios on air quality and aerosol-cloud interactions using an advanced version of CESM/CAM5: Part I. model evaluation for the current decadal simulations

Publication date: March 2017
Source:Atmospheric Environment, Volume 152
Author(s): Timothy Glotfelty, Jian He, Yang Zhang
A version of the Community Earth System Model modified at the North Carolina State University (CESM-NCSU) is used to simulate the current and future atmosphere following the representative concentration partway scenarios for stabilization of radiative forcing at 4.5 W m⁻² (RCP4.5) and radiative forcing of 8.5 W m⁻² (RCP8.5). Part I describes the results from a comprehensive evaluation of current decadal simulations. Radiation and most meteorological variables are well simulated in CESM-NCSU. Cloud parameters are not as well simulated due in part to the tuning of model radiation and general biases in cloud variables common to all global chemistry-climate models. The concentrations of most inorganic aerosol species (i.e., SO4^2-, NH4⁺, and NO3⁻) are well simulated with normalized mean biases (NMBs) typically less than 20%. However, some notable exceptions are European NH4⁺, which is overpredicted by 33.0–42.2% due to high NH3 emissions and irreversible coarse mode condensation, and Cl⁻, that is negatively impacted by errors in emissions driven by wind speed and overpredicted HNO3. Carbonaceous aerosols are largely underpredicted following the RCP scenarios due to low emissions of black carbon, organic carbon, and anthropogenic volatile compounds in the RCP inventory and efficient wet removal. This results in underpredictions of PM2.5 and PM10 by 6.4–55.7%. The column mass abundances are reasonably well simulated. Larger biases occur in surface mixing ratios of trace gases in CESM-NCSU, likely due to numerical diffusion from the coarse grid spacing of the CESM-NCSU simulations or errors in the magnitudes and vertical structure of emissions. This is especially true for SO2 and NO2. The mixing ratio of O3 is overpredicted by 38.9–76.0% due to the limitations in the O3 deposition scheme used in CESM and insufficient titration resulted from large underpredictions in NO2. Despite these limitations, CESM-NCSU reproduces reasonably well the current atmosphere in terms of radiation, clouds, meteorology, trace gases, aerosols, and aerosol-cloud interactions, making it suitable for future climate simulations.



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Heparin coatings for improving blood compatibility of medical devices

Publication date: Available online 29 December 2016
Source:Advanced Drug Delivery Reviews
Author(s): Roy Biran, Daniel Pond
Blood contact with biomaterials triggers activation of multiple reactive mechanisms that can impair the performance of implantable medical devices and potentially cause serious adverse clinical events. This includes thrombosis and thromboembolic complications due to activation of platelets and the coagulation cascade, activation of the complement system, and inflammation. Numerous surface coatings have been developed to improve blood compatibility of biomaterials. For more than thirty years, the anticoagulant drug heparin has been employed as a covalently immobilized surface coating on a variety of medical devices. This review describes the fundamental principles of non-eluting heparin coatings, mechanisms of action, and clinical applications with focus on those technologies which have been commercialized. Because of its extensive publication history, there is emphasis on the Carmeda® Bioactive Surface (CBAS® Heparin Surface), a widely used commercialized technology for the covalent bonding of heparin.

Graphical abstract

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The Chlamydia trachomatis Inclusion Membrane Protein CpoS Counteracts STING-Mediated Cellular Surveillance and Suicide Programs

Publication date: Available online 29 December 2016
Source:Cell Host & Microbe
Author(s): Barbara S. Sixt, Robert J. Bastidas, Ryan Finethy, Ryan M. Baxter, Victoria K. Carpenter, Guido Kroemer, Jörn Coers, Raphael H. Valdivia
Evading cell death is critical for Chlamydia to maintain a replicative niche, but the underlying mechanisms are unknown. We screened a library of Chlamydia mutants for modulators of cell death. Inactivation of the inclusion membrane protein CpoS (Chlamydia promoter of survival) induced rapid apoptotic and necrotic death in infected cells. The protection afforded by CpoS is limited to the inclusion in which it resides, indicating that it counteracts a spatially restricted pro-death signal. CpoS-deficient Chlamydia induced an exacerbated type I interferon response that required the host cGAS/STING/TBK1/IRF3 signaling pathway. Disruption of STING, but not cGAS or IRF3, attenuated cell death, suggesting that STING mediates Chlamydia-induced cell death independent of its role in regulating interferon responses. CpoS-deficient strains are attenuated in their ability to propagate in cell culture and are cleared faster from the murine genital tract, highlighting the importance of CpoS for Chlamydia pathogenesis.

Graphical abstract

Teaser

Evading cell death is critical for Chlamydia trachomatis to maintain a replicative niche. Sixt et al. show that the Chlamydia effector protein CpoS counteracts STING-mediated pro-death signals and type I IFN responses in response to Chlamydia-containing vacuoles, which enables optimal intracellular bacterial growth and survival in the murine genital tract.


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A Single Legionella Effector Catalyzes a Multistep Ubiquitination Pathway to Rearrange Tubular Endoplasmic Reticulum for Replication

Publication date: Available online 29 December 2016
Source:Cell Host & Microbe
Author(s): Kristin M. Kotewicz, Vinay Ramabhadran, Nicole Sjoblom, Joseph P. Vogel, Eva Haenssler, Mengyun Zhang, Jessica Behringer, Rebecca A. Scheck, Ralph R. Isberg
Intracellular pathogens manipulate host organelles to support replication within cells. For Legionella pneumophila, the bacterium translocates proteins that establish an endoplasmic reticulum (ER)-associated replication compartment. We show here that the bacterial Sde proteins target host reticulon 4 (Rtn4) to control tubular ER dynamics, resulting in tubule rearrangements as well as alterations in Rtn4 associated with the replication compartment. These rearrangements are triggered via Sde-promoted ubiquitin transfer to Rtn4, occurring almost immediately after bacterial uptake. Ubiquitin transfer requires two sequential enzymatic activities from a single Sde polypeptide: an ADP-ribosyltransferase and a nucleotidase/phosphohydrolase. The ADP-ribosylated moiety of ubiquitin is a substrate for the nucleotidase/phosphohydrolase, resulting in either transfer of ubiquitin to Rtn4 or phosphoribosylation of ubiquitin in the absence of a ubiquitination target. Therefore, a single bacterial protein drives a multistep biochemical pathway to control ubiquitination and tubular ER function independently of the host ubiquitin machinery.

Graphical abstract

Teaser

Intracellular pathogens, including Legionella, target host organelles for replication. Kotewicz et al. show that Legionella generates an ER-encompassed replication compartment via Sde protein-mediated ubiquitination of host reticulon 4. Ubiquitination is mediated by sequential action of the ADP-ribosyltransferase and nucleotidase activities of Sde and independent of the host ubiquitination system.


http://ift.tt/2iJw9h1

Prior Dietary Practices and Connections to a Human Gut Microbial Metacommunity Alter Responses to Diet Interventions

Publication date: Available online 29 December 2016
Source:Cell Host & Microbe
Author(s): Nicholas W. Griffin, Philip P. Ahern, Jiye Cheng, Andrew C. Heath, Olga Ilkayeva, Christopher B. Newgard, Luigi Fontana, Jeffrey I. Gordon
Ensuring that gut microbiota respond consistently to prescribed dietary interventions, irrespective of prior dietary practices (DPs), is critical for effective nutritional therapy. To address this, we identified DP-associated gut bacterial taxa in individuals either practicing chronic calorie restriction with adequate nutrition (CRON) or without dietary restrictions (AMER). When transplanted into gnotobiotic mice, AMER and CRON microbiota responded predictably to CRON and AMER diets but with variable response strengths. An individual's microbiota is connected to other individuals' communities ("metacommunity") by microbial exchange. Sequentially cohousing AMER-colonized mice with two different groups of CRON-colonized mice simulated metacommunity effects, resulting in enhanced responses to a CRON diet intervention and changes in several metabolic features in AMER animals. This response was driven by an influx of CRON DP-associated taxa. Certain DPs may impair responses to dietary interventions, necessitating the introduction of diet-responsive bacterial lineages present in other individuals and identified using the strategies described.

Graphical abstract

Teaser

Ensuring that gut microbiota respond consistently to dietary interventions is critical for nutritional therapy. Griffin et al. find that dietary practices alter the human gut microbiota. The magnitude of microbiota responses to diet interventions varies among individuals. Dispersal of diet-responsive bacterial taxa between hosts enhances subsequent responses to diet interventions.


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Positive Gene Regulation by a Natural Protective miRNA Enables Arbuscular Mycorrhizal Symbiosis

Publication date: Available online 29 December 2016
Source:Cell Host & Microbe
Author(s): Jean-Malo Couzigou, Dominique Lauressergues, Olivier André, Caroline Gutjahr, Bruno Guillotin, Guillaume Bécard, Jean-Philippe Combier
Arbuscular mycorrhizal (AM) symbiosis associates most plants with fungi of the phylum Glomeromycota. The fungus penetrates into roots and forms within cortical cell branched structures called arbuscules for nutrient exchange. We discovered that miR171b has a mismatched cleavage site and is unable to downregulate the miR171 family target gene, LOM1 (LOST MERISTEMS 1). This mismatched cleavage site is conserved among plants that establish AM symbiosis, but not in non-mycotrophic plants. Unlike other members of the miR171 family, miR171b stimulates AM symbiosis and is expressed specifically in root cells that contain arbuscules. MiR171b protects LOM1 from negative regulation by other miR171 family members. These findings uncover a unique mechanism of positive post-transcriptional regulation of gene expression by miRNAs and demonstrate its relevance for the establishment of AM symbiosis.

Graphical abstract

Teaser

Arbuscular mycorrhizal symbiosis, a plant-fungal mutualistic relationship, is regulated by the miR171 family. Couzigou et al. discover that miR171b has evolved a target site mismatch such that instead of silencing, miR171b protects its target gene LOM1 from cleavage by other miR171 family members and thereby enables AM symbiosis.


http://ift.tt/2htnkDe

Data on the optimizations of expression and purification of human BiP/GRP78 protein in Escherichia coli

Publication date: February 2017
Source:Data in Brief, Volume 10
Author(s): Jiao Yang, Lei Zhou, Qinglian Liu
Human BiP/GRP78 is involved in the folding and assembly of proteins in the endoplasmic reticulum. The proteins for crystallization in good amount and quality are prerequisites for obtaining ideal crystals. To meet these requirements, different BiP/GRP78 constructs, competent cells, vectors, and concentrations of inducer were tested in order to obtain soluble BiP/GRP78 protein with the highest amount and best purity. The BiP–T229A–L3,4′–Smt3 fusion protein was expressed in a soluble manner and finally purified with the highest purity using size exclusion chromatography, which was suitable for further protein crystallization.



http://ift.tt/2htcJIl

Myosin phosphorylation on stress fibers predicts contact guidance behavior across diverse breast cancer cells

Publication date: March 2017
Source:Biomaterials, Volume 120
Author(s): Juan Wang, Ian C. Schneider
During cancer progression the extracellular matrix is remodeled, forming aligned collagen fibers that proceed radially from the tumor, resulting in invasion. We have recently shown that different invasive breast cancer cells respond to epitaxially grown, aligned collagen fibrils differently. This article develops insight into why these cells differ in their contact guidance fidelity. Small changes in contractility or adhesion dramatically alter directional persistence on aligned collagen fibrils, while migration speed remains constant. The directionality of highly contractile and adhesive MDA-MB-231 cells can be diminished by inhibiting Rho kinase or β1 integrin binding. Inversely, the directionality of less contractile and adhesive MTLn3 cells can be enhanced by activating contractility or integrins. Subtle, but quantifiable alterations in myosin II regulatory light chain phosphorylation on stress fibers explain the tuning of contact guidance fidelity, separate from migration per se indicating that the contractile and adhesive state of the cell in combination with collagen organization in the tumor microenvironment determine the efficiency of migration. Understanding how distinct cells respond to contact guidance cues will not only illuminate mechanisms for cancer invasion, but will also allow for the design of environments to separate specific subpopulations of cells from patient-derived tissues by leveraging differences in responses to directional migration cues.



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Factors Determining Scientific Paper Productivity by Neuroradiology Fellows

Publication date: Available online 29 December 2016
Source:Academic Radiology
Author(s): Ivana Zupetic, Ilyssa J. Yousem, Li Liu, Nafi Aygun, David M. Yousem
Rationale and ObjectivesWe sought to determine (1) whether United States Medical Licensing Examination (USMLE) scores predict academic productivity in neuroradiology fellows as measured by publications and citations, and (2) what factors predict such productivity.Materials and MethodsWe reviewed the USMLE scores, gender, medical school location attended, publication record before and during fellowship, fellowship evaluation ratings and subsequent practice site (private vs academic) of neuroradiology fellows from 2004 to 2014 to determine relationships with publications and citations after fellowship. Spearman's correlation and Poisson regression analyses were performed to assess the association between these factors and quantity of publications and citations per year after fellowship.ResultsUSMLE scores and fellowship evaluation scores correlated inversely with radiology publications and citations. There were strong correlations between publication records before or during fellowship and after fellowship. Fellows from international medical schools, with PhD degrees, and those fellows proceeding to academic practice had more publications before or during and after neuroradiology fellowship.ConclusionsThe best predictors of whether a graduating neuroradiology fellow will publish and have high citation rates is prior publication record, a PhD degree, and staying in academics. USMLE scores and evaluations during the fellowship were inversely correlated with publication measures of academic productivity.



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Radiology Research Alliance Task Forces: An Opportunity to Shape the Future

Publication date: Available online 29 December 2016
Source:Academic Radiology
Author(s): Leon Lenchik




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The prevention of benign prostatic hyperplasia (bph)

Publication date: Available online 29 December 2016
Source:Medical Hypotheses
Author(s): W.G. Roper
Barry Marshall and Robin Warren were the first to show that the chronic diseases (gastric ulcer and chronic gastritis) were caused by an infection (Helicobacter Pylori)The chronic disease Benign Prostatic Hyperplasia belongs to the same ilk, except that the infection process is much more subtle and complex.



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Marine actinobacteria as a drug treasure house

Publication date: March 2017
Source:Biomedicine & Pharmacotherapy, Volume 87
Author(s): Syed Shams ul Hassan, Abdul Lateef Shaikh
Marine actinobacteria have been considered as a gold mine with respect to great potential regarding their secondary metabolites. Most of the researches have been conducted on actinobacteria's derived secondary metabolites to examine its pharmacological properties. Actinobacteria have a potential to provide future drugs against crucial diseases, such as drug-resistance bacteria, cancer, a range of viral illnesses, malaria, several infections and inflammations. Although, the mode of action of many bio molecules are still untapped, for a tangible number of compounds by which they interfere with human pathogenesis are reported here with detailed diagrammed illustrations. This knowledge is one of the basic vehicles to be known especially for transforming bio medicinal molecules to medicines. Actinobacteria produce a different kind of biochemical substances with numerous carbon skeletons, which have been found to be the main component interfering with human pathogenesis at different sites. Different diseases have the capability to fight at different sites inside the body can lead to a new wave of increasing the chances to produce targeted medicines.



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Transcriptome analysis of EGFR tyrosine kinase inhibitors resistance associated long noncoding RNA in non-small cell lung cancer

Publication date: March 2017
Source:Biomedicine & Pharmacotherapy, Volume 87
Author(s): Pei Ma, Meiling Zhang, Fengqi Nie, Zebo Huang, Jing He, Wei Li, Liang Han
The non–small cell lung cancer (NSCLC) patients harbor mutations in the epidermal growth factor receptor (EGFR) can be therapeutically targeted by EGFR tyrosine kinase inhibitors (EGFR-TKI), such as gefitinib, and show improved progression-free survival. However, most of the patients who are initially responsive to EGFR TKIs with activating EGFR mutations eventually develop acquired resistance after long-term therapy, and are followed by disease progression. Recently, diverse mechanisms of acquired EGFR TKI resistance have been reported, but little is known about the role of long noncoding RNAs in EGFR TKIs resistance. To gain insight into the expression pattern and potential function of lncRNAs in NSCLC cells EGFR-TKI resistance, we analyzed expression patterns in EGFR-TKIs-resistant cell lines and compared it with their parental sensitive cell line by using gene profiling datasets from Gene Expression Omnibus (GEO). Then, the expression levels of five chose lncRNAs were validated in PC9-gefitinib resistant cells (PC9G) and sensitive cells by using real-time quantitative PCR (qPCR). Among of these five lncRNAs, CASC9 expression was upregulated in PC9G and knockdown of its expression could increase the sensitivity of PC9G cells to gefitinib, while EWAST1 (LINC00227) is downregulated in PC9G cells and overexpressed EWAST1 also lead to increased sensitivity of PC9G cells to gefitinib. As indicated by GO analysis, the CASC9 and EWAST1 co-expressed genes are involved in several important pathways including regulation of cell growth, regulation of cell apoptosis and Chromatin assembly. Taken together, dysregulated lncRNAs play critical roles in EGFR-TKIs resistant NSCLC cells and might be used as novel potential targets to reverse EGFR-TKI resistance for NSCLC patients.



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Effects of anesthetic and analgesic techniques on cancer metastasis

Publication date: March 2017
Source:Biomedicine & Pharmacotherapy, Volume 87
Author(s): Sepideh Vahabi, Ali Eatemadi
The rate of mortality and morbidity among cancer patients is at an alarming rate and its ratio of incidence is increasing as a result of its effects of metastasis and recurrence in its patients. Several factors including anesthetic agents and analgesia techniques have been identified as causative agents for cancer metastasis. In this mini-review, we will summarize some of the available effects of anesthetic and analgesic techniques on cancer metastasis as derived from experimental cell culture and live animal data and also form clinical studies.



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Specific executive control impairments in Tourette syndrome: The role of response inhibition

Publication date: February 2017
Source:Research in Developmental Disabilities, Volume 61
Author(s): Asaf Yaniv, Noa Benaroya-Milshtein, Tamar Steinberg, Dafna Ruhrrman, Alan Apter, Michal Lavidor
BackgroundTourette syndrome (TS) is a childhood-onset disorder characterized by motor and vocal tics. While cognitive features of common comorbid conditions such as attention deficit hyperactive disorder and obsessive compulsive disorder have been widely investigated, the cognitive profile of TS patients remains to be precisely defined. In this regard, the executive functions system (EF) is of especial interest.AimsThe aim of the study was to delineate the various components of executive processes in adult TS patients.MethodsA sample of 19 adults diagnosed with TS and 19 age-matched control subjects underwent computerized battery of executive tasks, as well as block design and memory tests. All patients received a thorough clinical assessment with an emphasis on illness severity.ResultsThere was a marked impairment in response inhibition ability regardless of comorbid conditions, In addition, there was decreased accuracy in set shifting, but not in response time. These results imply that impaired response inhibition in the EF system is the primary cognitive impairment in TS and that many of the previously reported impaired executive functions in TS are secondary to this impairment.ConclusionsThis finding of impaired response inhibition in TS may imply that rehabilitation of this inhibition component could prove to be an important therapeutic strategy in adults with TS.



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The earliest long-distance obsidian transport: Evidence from the ∼200 ka Middle Stone Age Sibilo School Road Site, Baringo, Kenya

Publication date: February 2017
Source:Journal of Human Evolution, Volume 103
Author(s): Nick Blegen
This study presents the earliest evidence of long-distance obsidian transport at the ∼200 ka Sibilo School Road Site (SSRS), an early Middle Stone Age site in the Kapthurin Formation, Kenya. The later Middle Pleistocene of East Africa (130–400 ka) spans significant and interrelated behavioral and biological changes in human evolution including the first appearance of Homo sapiens. Despite the importance of the later Middle Pleistocene, there are relatively few archaeological sites in well-dated contexts (n < 10) that document hominin behavior from this time period. In particular, geochemically informed evidence of long-distance obsidian transport, important for investigating expansion of intergroup interactions in hominin evolution, is rare from the Middle Pleistocene record of Africa. The SSRS offers a unique contribution to this small but growing dataset. Tephrostratigraphic analysis of tuffs encasing the SSRS provides a minimum age of ∼200 ka for the site. Levallois points and methods of core preparation demonstrate characteristic Middle Stone Age lithic technologies present at the SSRS. A significant portion (43%) of the lithic assemblage is obsidian. The SSRS obsidian comes from three different sources located at distances of 25 km, 140 km and 166 km from the site. The majority of obsidian derives from the farthest source, 166 km to the south of the site. The SSRS thus provides important new evidence that long-distance raw material transport, and the expansion of hominin intergroup interactions that this entails, was a significant feature of hominin behavior ∼200 ka, the time of the first appearance of H. sapiens, and ∼150,000 years before similar behaviors were previously documented in the region.



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Spectroscopic quantification of 5-hydroxymethylcytosine in genomic DNA using boric acid-functionalized nano-microsphere fluorescent probes

Publication date: 15 May 2017
Source:Biosensors and Bioelectronics, Volume 91
Author(s): Hua-yan Chen, Jing-Ru Wei, Jiong-Xiu Pan, Wei Zhang, Fu-quan Dang, Zhi-Qi Zhang, Jing Zhang
5-hydroxymethylcytosine (5hmC) is the sixth base of DNA. It is involved in active DNA demethylation and can be a marker of diseases such as cancer. In this study, we developed a simple and sensitive 2-(4-boronophenyl)quinoline-4-carboxylic acid modified poly (glycidyl methacrylate (PBAQA-PGMA) fluorescent probe to detect the 5hmC content of genomic DNA based on T4 β-glucosyltransferase-catalyzed glucosylation of 5hmC. The fluorescence-enhanced intensity recorded from the DNA sample was proportional to its 5-hydroxymethylcytosine content and could be quantified by fluorescence spectrophotometry. The developed probe showed good detection sensitivity and selectivity and a good linear relationship between the fluorescence intensity and the concentration of 5 hmC within a 0–100nM range. Compared with other fluorescence detection methods, this method not only could determine trace amounts of 5 hmC from genomic DNA but also could eliminate the interference of fluorescent dyes and the need for purification. It also could avoid multiple labeling. Because the PBAQA-PGMA probe could enrich the content of glycosyl-5-hydroxymethyl-2-deoxycytidine from a complex ground substance, it will broaden the linear detection range and improve sensitivity. The limit of detection was calculated to be 0.167nM after enrichment. Furthermore, the method was successfully used to detect 5-hydroxymethylcytosine from mouse tissues.



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