2,677 research outputs found

    Biochemical characterization and DNA repair pathway interactions of Mag1-mediated base excision repair in Schizosaccharomyces pombe

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    The Schizosaccharomyces pombe mag1 gene encodes a DNA repair enzyme with sequence similarity to the AlkA family of DNA glycosylases, which are essential for the removal of cytotoxic alkylation products, the premutagenic deamination product hypoxanthine and certain cyclic ethenoadducts such as ethenoadenine. In this paper, we have purified the Mag1 protein and characterized its substrate specificity. It appears that the substrate range of Mag1 is limited to the major alkylation products, such as 3-mA, 3-mG and 7-mG, whereas no significant activity was found towards deamination products, ethenoadducts or oxidation products. The efficiency of 3-mA and 3-mG removal was 5–10 times slower for Mag1 than for Escherichia coli AlkA whereas the rate of 7-mG removal was similar to the two enzymes. The relatively low efficiency for the removal of cytotoxic 3-methylpurines is consistent with the moderate sensitivity of the mag1 mutant to methylating agents. Furthermore, we studied the initial steps of Mag1-dependent base excision repair (BER) and genetic interactions with other repair pathways by mutant analysis. The double mutants mag1 nth1, mag1 apn2 and mag1 rad2 displayed increased resistance to methyl methanesulfonate (MMS) compared with the single mutants nth1, apn2 and rad2, respectively, indicating that Mag1 initiates both short-patch (Nth1-dependent) and long-patch (Rad2-dependent) BER of MMS-induced damage. Spontaneous intrachromosomal recombination frequencies increased 3-fold in the mag1 mutant suggesting that Mag1 and recombinational repair (RR) are both involved in repair of alkylated bases. Finally, we show that the deletion of mag1 in the background of rad16, nth1 and rad2 single mutants reduced the total recombination frequencies of all three double mutants, indicating that abasic sites formed as a result of Mag1 removal of spontaneous base lesions are substrates for nucleotide excision repair, long- and short-patch BER and RR

    Evaluation of Biological Activities of Extracts and Chemical Constituents of Mimusops elengi

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    Purpose: To isolate some compounds from the leaves and bark of Mimusops elengi, and examine them for their antibacterial and anti-inflammatory properties.Experimental: The compounds were isolated from the leaf and bark chloroform extracts using column chromatography, and characterized using physical and spectroscopic methods. The isolated compounds and their respective extracts were tested for antibacterial activity by micro-dilution antibacterial assay, and for anti-inflammatory activity by cyclooxygenase inhibitory assay.Results: of the compounds isolated include spinasterol (1), ursolic acid (2) and 3β, 6β, 19α, 23- tetrahydroxyurs-12-en-28-oic acid (3) from the leaves; and taraxerol (4) and spinasterol β-Dglucopyranoside (5) from the bark. A majority of the samples showed good activity against Staphylococcus aureus (9.7 ─ 78.0 μg/mL), while moderate activity was observed against Gramnegative bacteria (78.0 ─ 156 μg/mL). Strong COX inhibition was observed for the leaf extract, and (1); selective COX-2 inhibition for (2) and (3); and selective COX-1 inhibition for bark extract, (4) and (5).Conclusion: This is the first report describing the anti-inflammatory potential of M. elengi on the basis of its isolated constituents. The results of this study support the traditional use of the plant as antibacterial and anti-inflammatory remedy.Keywords: Mimusops elengi, Sapotaceae, Steroids; Triterpenoids, Antibacterial, Antiinflammatory

    Geometric Quantization on the Super-Disc

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    In this article we discuss the geometric quantization on a certain type of infinite dimensional super-disc. Such systems are quite natural when we analyze coupled bosons and fermions. The large-N limit of a system like that corresponds to a certain super-homogeneous space. First, we define an example of a super-homogeneous manifold: a super-disc. We show that it has a natural symplectic form, it can be used to introduce classical dynamics once a Hamiltonian is chosen. Existence of moment maps provide a Poisson realization of the underlying symmetry super-group. These are the natural operators to quantize via methods of geometric quantization, and we show that this can be done.Comment: 17 pages, Latex file. Subject: Mathematical physics, geometric quantizatio

    Taste function in early stage treated and untreated Parkinson’s disease

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    Since brain stem regions associated with early Parkinson’s disease (PD) pathology encroach upon those involved in taste function, the ability to taste may be compromised in PD. However, studies on this point have been contradictory. We administered well-validated wholemouth and regional taste tests that incorporated multiple concentrations of sucrose, citric acid, caffeine, and sodium chloride to 29 early stage PD patients and 29 age-, sex-, and race-matched controls. Electrogustometry was also performed on the anterior tongue. The PD cohort was tested both on and off dopamine-related medications in counterbalanced test sessions. While whole-mouth taste identification test scores for all stimuli were, on average, nominally lower for the PD patients than for the controls, a trend in the opposite direction was noted for the intensity ratings at the lower stimulus concentrations for all stimuli except caffeine. Moreover, regional testing found that PD subjects tended to rate the stimuli, relative to the controls, as more intense on the anterior tongue and less intense on the posterior tongue. No significant associations were evident between taste test scores and UPDRS scores, L-DOPA medication equivalency values, or [99mTc]TRODAT-1 SPECT imaging of dopamine transporter uptake within the striatum and associated regions. Our findings suggest that suprathreshold measures of taste function are influenced by PD and that this disease differentially influences taste function on anterior (CN VII) and posterior (CN IX) tongue regions. Conceivably PD-related damage to CN IX releases central inhibition on CN VII at the level of the brainstem, resulting in enhanced taste intensity on the anterior tongue

    An Optical Flow Measurement Technique based on Continuous Wavelet Transform

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    Flow measurement underwater oil leak is a challenging problem, due to the complex nature of flow dynamics. Oil jet flow associated with a multi-scale coherent structure in both space and time direction. Optical plume velocimetry (OPV) was developed by (Crone, McDuff, and Wilcock, 2008), and it was the most accurate technique that used for oil leak flow measurement. Despite its better estimation, the OPV measured the oil flow rate with high uncertainty of 21%. This is due to the multi-scale phenomena of oil flow, as well as the limited accuracy of direct cross correlation (DCC) typically used by OPV. This paper proposed a novel technique that considers the multi-scale property of turbulence in flow measurement. The proposed technique is based on continuous wavelet transform and estimates the flow using the following steps: Decomposition of turbulent flow signal by using continuous wavelet transform (CWT), correlation coefficient estimation in which Fast Fourier Transform (FFT) algorithm was used, interpolation and peak detection for the estimated correlation coefficients, and finally, the velocity field estimation. In order to validate the CWT-based technique, a turbulent buoyant jet, which has a similar flow-type of oil jet was experimentally simulated. Then, the CWT-based technique was applied to measure the jet flow, and the outcomes of the technique was compared to the experimental results. As a result, utilizing a smaller number of wavelet scales lead in better flow measurement as compared to the use of larger scales. CWT-based technique was accurately estimated the jet flow rate with standard error of 0.15 m/s, and outperformed the classical algorithms, including FFT, and DCC algorithms, which were measured with error of 3.65 m/s and 4.53 m/s respectively

    Hyperthyroidism as a reversible cause of right ventricular overload and congestive heart failure

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    We describe a case of severe congestive heart failure and right ventricular overload associated with overt hyperthyroidism, completely reversed with antithyroid therapy in a few week. It represents a very unusual presentation of overt hyperthyroidism because of the severity of right heart failure. The impressive right ventricular volume overload made mandatory to perform transesophageal echo and angio-TC examination to exclude the coexistence of ASD or anomalous pulmonary venous return. Only a few cases of reversible right heart failure, with or without pulmonary hypertension, have been reported worldwide. In our case the most striking feature has been the normalization of the cardiovascular findings after six weeks of tiamazole therapy

    Unraveling the chemical profile, antioxidant, enzyme inhibitory, cytotoxic potential of different extracts from Astragalus caraganae

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    Six extracts (water, ethanol, ethanol‐water, ethyl acetate, dichloromethane, and n‐hexane) of Astragalus caraganae were studied for their biological activities and bioactive contents. Based on high‐performance liquid chromatography‐mass spectrometry (HPLC‐MS), the ethanol‐water extract yielded the highest total bioactive content (4242.90 μg g−1), followed by the ethanol and water extracts (3721.24 and 3661.37 μg g−1, respectively), while the least total bioactive content was yielded by the hexane extract, followed by the dichloromethane and ethyl acetate extracts (47.44, 274.68, and 688.89 μg g−1, respectively). Rutin, p‐coumaric, chlorogenic, isoquercitrin, and delphindin‐3,5‐diglucoside were among the major components. Unlike the dichloromethane extracts, all the other extracts showed radical scavenging ability in the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay (8.73–52.11 mg Trolox equivalent [TE]/g), while all extracts displayed scavenging property in the 2,2‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) radical scavenging assay (16.18–282.74 mg TE/g). The extracts showed antiacetylcholinesterase (1.27–2.73 mg galantamine equivalent [GALAE]/g), antibutyrylcholinesterase (0.20–5.57 mg GALAE/g) and antityrosinase (9.37–63.56 mg kojic acid equivalent [KAE]/g) effects. The molecular mechanism of the H2O2‐induced oxidative stress pathway was aimed to be elucidated by applying ethanol, ethanol/water and water extracts at 200 μg/mL concentration to human dermal cells (HDFs). A. caraganae in HDF cells had neither a cytotoxic nor genotoxic effect but could have a cytostatic effect in increasing concentrations. The findings have allowed a better insight into the pharmacological potential of the plant, with respect to their chemical entities and bioactive contents, as well as extraction solvents and their polarity

    Insecticidal Activity of the Essential Oils from Different Plants Against Three Stored-Product Insects

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    This study was conducted to determine the insecticidal activity of essential oils from oregano, Origanum onites L. (Lamiales: Lamiaceae), savory, Satureja thymbra L. (Lamiales: Lamiaceae), and myrtle, Myrtus communis L. (Rosales: Myrtaceae) against three stored-product insects. Essential oils from three species of plants were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified using gas chromatography-mass spectrometry and their insecticidal activity was tested against adults of the Mediterranean flour moth Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), the Indian meal moth Plodia interpunctella HĂźbner (Lepidoptera: Pyralidae) and the bean weevil Acanthoscelides obtectus Say (Coleoptera: Bruchidae). While the major compound found in oregano and savory was carvacrol, the main constituent of the myrtle was linalool. Among the tested insects, A. obtectus was the most tolerant species against the essential oils. However, the insecticidal activity of the myrtle oil was more pronounced than other oils tested against A. obtectus adults. The essential oils of oregano and savory were highly effective against P. interpunctella and E. kuehniella, with 100% mortality obtained after 24 h at 9 and 25 Âľl/l air for P. interpunctella and E. kuehniella, respectively. LC50 and LC99 values of each essential oil were estimated for each insect species

    Intelligent decision support system based geo-information technology and spatial planning for sustainable water management in Flanders, Belgium

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    The paper outlines the main features of an intelligent decision support system based on existing and planned tools for optimising water management and flood risk reduction. Up to now, flood risk is increasing and environmental degradation is continuing; this requires developing robotic algorithms that can provide a degree of functionality for spatial representation and flexibility suitable for creating real-time solutions that maximize the urban flood protection measures. Moreover, the volume of data collected is growing rapidly and sophisticated means to efficiently optimise the data are essential. There is a need to develop a shared information system for flood management which will promote model and systems integration, monitoring, and decision making in strategic planning and emergency situations. This advanced area of research is a promising direction for producing an effective time-efficient solution to flood risk reduction where other methods failed. Therefore, the objective of this paper is to bring together innovative methods in the field of artificial intelligence, geo-information technology and spatial and environmental planning to achieve more effective water management and flood risk reduction in Flanders
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