Single-walled carbon nanotubes binding to human telomeric i-motif DNA under molecular-crowding conditions: More water molecules released

The natural occurrence of the human telomeric G-quadruplex or i-motif in vivo has not been demonstrated and the biological effects of the induction of these structures need to be clarified. Intracellular environments are highly crowded with various biomolecules and in vitro studies under molecular-crowding conditions will provide important information on how biomolecules behave in cells. Here we report that cell-mimic crowding can increase i-motif stability at acid pH and cause dehydration.

米托蒽醌与双链及三链核酸相互作用的电喷雾质谱研究

The interaction of mitoxantrone (MXT) with duplex and triplex DNA, contain repeating sequence CTCT, CCTT and CTT were studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). The 1:3 specific complexes of mitoxantrone and duplex DNA and 1:2 specific complexes of mitoxantrone and triplex DNA were observed. The results show that mitoxantrone has no remarkable sequence selectivity, however it has distinct structure selectivity, and destabilization the triplex.

Evaluation of Effects of Bivalent Cations on the Formation of Purine-rich Triple-Helix DNA by ESI-FT-MS

The GGA triplet repeats are widely dispersed throughout eukaryotic genomes. (GGA)n or (GGT)n oligonucleotides can interact with double-stranded DNA containing (GGA:CCT)n to form triple-stranded DNA. The effects of 8 divalent metal ions (3 alkaline-earth metals and 5 transition metals) on formation of these purine-rich triple-helix DNA were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-MS). In the absence of metal ions, no triplex but single-strand, duplex, and purine homodimer ions were observed in mass spectra. The triple-helix DNA complexes were observed only in the presence of certain divalent ions. The effects of different divalent cations on the formation of purine-rich triplexes were compared. Transition-metal ions, especially Co2+ and Ni2+, significantly boost the formation of triple-helix DNA, whereas alkaline-earth metal ions have no positive effects on triplex formation. In addition, Ba2+ is notably beneficial to the formation of homodimer instead of triplex.

A study of the non-covalent interaction between flavonoids and DNA triplexes by electrospray ionization mass spectrometry

The binding interactions of 22 flavonoids (9 aglycones and 13 glycosides) with DNA triplexes were investigated using electrospray ionization mass spectrometry (ESI-MS). The results revealed that the hydroxyl positions of aglycones. the locations and numbers of saccharide, as well as the aglycone skeletons play roles in the triplex-binding properties of flavonoids. The presence of 3-OH, or 3'-OH, or replacement of 4'-OH with methoxy group in aglycones decreased the fraction of bound DNA sharply. Flavonoid glycosides exhibit higher binding affinities towards the DNA triplexes than their aglycone counterparts. Glycosylations of flavones at the 8-C position and isoflavones at the 7-O position show higher binding affinities than those on the other positions of ring A of aglycones. Glycosylation with a disaccharide on 0 position of flavonol results in higher binding affinity than that with monosaccharide. Flexibility of the ring B is favorable for its interaction with DNA triplex. According to sustained off-resonance irradiation collision-induced dissociation (SORI-CID) experiments, glycosylation and non-planarity of flavonoid aglycones lead to different dissociation pathways of the flavonoid/triplex complexes.

Structural selectivity of aromatic diamidines

Competition dialysis was used to study the interactions of 13 substituted aromatic diamidine compounds with 13 nucleic acid structures and sequences. The results show a striking selectivity of these compounds for the triplex structure poly dA:(poly dT)(2), a novel aspect of their interaction with nucleic acids not previously described. The triplex selectivity of selected compounds was confirmed by thermal denaturation studies. Triplex selectivity was found to be modulated by the location of amidine substiuents on the core phenyl-furan-phenyl ring scaffold. Molecular models were constructed to rationalize the triplex selectivity of DB359, the most selective compound in the series. Its triplex selectivity was found to arise from optimal ring stacking on base triplets, along with proper positioning of its amidine substituents to occupy the minor and the major-minor grooves of the triplex. New insights into the molecular recognition of nucleic acid structures emerged from these studies, adding to the list of available design principles for selectively targeting DNA and RNA.

基于流域—库区—坝区模型“三重边界嵌套”方法的河南济源蟒河口水库渗漏数值模拟研究

Constructing reservoir in mountain area, in order to avoid dangerous reservoir and ensure long-term stable reservoir storage, study on reservoir leakage has been one of research hotspots. How to accurately predict the capacity of leakage and the effect of anti-seepage after reservoir impoundment under different anti-seepage measures is one of the most difficult problems of study on reservoir leakage. The paper took Manghekou Reservoir as a case study, which is located in Jiyuan City, Henan Province, China. Based on the system analysis of the geological and hydrogeological characters in the research area, the hydrogeological conceptual model was established. Then, according to the triplex boundary nested grid model method, using three-dimensional numerical simulation technique, the 3-D groundwater seepage flow numerical model was established in the study area. Based on the model, the change of seepage flow field, the capacity of leakage and the effect of anti-seepage are predicted after Manghekou reservoir impoundment under different condition. The reasonable and reliable anti-seepage measure is selected according to the model. All these provides scientific basis for the design and assessment of anti-seepage measure for the reservoir in mountain area.

Mélanges concernant le portrait idéal d'un roi, l'alchimie, l'histoire de France, jusqu'à Charles VII, ledit roi Charles VII et son fils le dauphin Louis; opuscule de Guillaume Postel.

Contient : 1 Traité de morale intitulé : « Triplex vita regis ». Le commencement de ce traité manque (une ancienne foliotation semble indiquer qu'il ne manque que le premier feuillet) ; les premiers mots du manuscrit sont : « Si doit et scet mieulx dire Rex in eternum vive... ». A la fin, on lit : « Explicit de Triplici vita regis ». — « Iste liber est monasterii Celestinorum Sancte Trinitatis prope Meduntam » ; 2 Remontrances par « JEHAN DU BOIS » au roi [Charles VII], sous forme de traité didactique en cinq parties, sur les causes des malheurs de la France et leurs remèdes ; A Préface « O vos omnes qui transitis... » ; B table des cinq parties ; C traité dont les premiers mots sont : « Très doulz, très begnin et très humble roy et empereur des François... » et les derniers : «... et pour tout l'umain lignage que à ce faire vous vueille inspirer le Saint Esperit. Amen » ; 3 Traité d'alchimie ; 4 « Parolles que dirent les gens du roy Charles VII à Louis son filz, depuis Louis XI, lorsqu'il se retira vers le duc de Bourgogne. 1456 » ; 5 Chronique des rois de France, depuis les origines jusqu'à la mort de Charles VII inclusivement ; 6 « Les retractations de Guillaume Postel touchant les propos de la mère Joanne, aultrement dicte la vierge vénetiane », adressées à Catherine de Médicis en 1564

La Demande Residentielle D'eau, Ville de Saint-Laurent, 1978

Dans Ce Texte Nous Examinons a L'aide D'un Echantillon de 560 Menages et des Moindres Carrees Ordinaires les Determinants de la Consommation Residentielle D'eau a Ville Saint-Laurent (Quebec) En 1978. Nos Resultats Nous Indiquent Que L'evaluation Fonciere des Proprietes, le Nombre de Pieces Par Logement et la Taille du Menage Sont Trois Variables Qui Expliquent la Consommation D'eau de Menages Habitant des Residences Unifamiliales Ou des Logements Dans des Duplex, Triplex Ou Quadruplex. Nos Resultats Sont Similaires a Ceux D'etudes Americaines et a Ceux Obtenus Pour Ville Saint-Leonard (Quebec) En 1977.

Multiplexed femtomolar quantitation of human cytokines in a fluoropolymer microcapillary film

Sensitive quantitation of multiple cytokines can provide important diagnostic information during infection, inflammation and immunopathology. In this study sensitive immunoassay detection of human cytokines IL-1β, IL-6, IL-12p70 and TNFα is shown for singleplex and multiplex formats using a novel miniaturized ELISA platform. The platform uses a disposable plastic multi-syringe aspirator (MSA) integrating 8 disposable fluoropolymer microfluidic test strips, each containing an array of ten 200 mean i.d. microcapillaries coated with a set of monoclonal antibodies. Each MSA device thus performs 10 tests on 8 samples, delivering 80 measurements. Unprecedented levels of sensitivity were obtained with the novel fluoropolymer microfluidic material and simple colorimetric detection in a flatbed scanner. The limit of detection for singleplex detection ranged from 2.0 to 15.0 pg/ml, i.e. 35 and 713 femtomolar for singleplex cytokine detection, and the intra- and inter-assay coefficient of variation (CV) remained within 10%. In addition, a triplex immunoassay was developed for measuring IL-1β, IL-12p70 and TNFα simultaneously from a given sample in the pg/ml range. These assays permit high sensitivity measurement with rapid <15 min assay or detection from undiluted blood serum. The portability, speed and low-cost of this system are highly suited to point-of-care testing and field diagnostics applications.

Potential sites of triple-helical nucleic acid formation in chromosomes of Rhynchosciara (Diptera: Sciaridae) and Drosophila melanogaster

Antibodies to specific nucleic acid conformations are amongst the methods that have allowed the study of non-canonical (Watson-Crick) DNA structures in higher organisms. In this work, the structural limitations for the immunological detection of DNA.RNA hybrid duplexes were examined using specific RNA homopolymers as probes for homopolymer polydeoxyadenylic acid (poly(dA)).polydeoxythymidylic acid (poly(dT))-rich regions of Rhynchosciara americana (Diptera: Sciaridae) chromosomes. Anti-DNA.RNA duplexes did not react with the complex formed between chromosomal poly(dA) and exogenous polyuridylic acid (poly(rU)). Additionally, poly(rU) prevented the detection of polyadenylic acid.poly(dT) hybrid duplexes preformed in situ. These results raised the possibility that three-stranded structures rather than duplexes were formed in chromosomal sites. To test this hypothesis, the specificity of antibodies to triple-helical nucleic acids was reassessed employing distinct nucleic acid configurations. These antibodies were raised to the poly(dA).poly(rU).poly(rU) complex and have been used here for the first time in immunocytochemistry. Anti-triplex antibodies recognised the complex poly(dA).poly(rU).poly(rU) assembled with poly(rU) in poly(dA).poly(dT)-rich homopolymer regions of R. americana chromosomes. The antibodies could not detect short triplex stretches, suggesting the existence of constraints for triple-helix detection, probably related to triplex tract length. In addition, anti-poly(dA).poly(rU).poly(rU) antibodies reacted with the pericentric heterochromatin of RNase-treated polytene chromosomes of R. americana and Drosophila melanogaster. In apparent agreement with data obtained in cell types from other organisms, the results of this work suggest that significant triple-helix DNA extensions can be formed in pericentric regions of these species.

O gênero geastrum pers. (phallomycetidae, basidiomycota) em algumas áreas de Mata Atlântica e Caatinga no Rio Grande do Norte, Brasil

A taxonomic survey of representatives of the genus Geastrum took place during the rainy season from 2006 to 2009 in four districts in the state of Rio Grande do Norte: Parque Estadual Dunas do Natal (Atlantic Forest), Mata do Jiqui EMPARN (Atlantic Forest) and Estação Ecológica do Seridó (Caatinga). Fourteen species were recorded: G. entomophilum, G. fimbriatum, G. hirsutum, G. javanicum, G. lageniforme, G. lloydianum, G. minimum, G. morganii, G. ovalisporum, G. pectinatum, G. saccatum, G. schweinitzii, G. setiferum and G. triplex. Of these species, eleven occurred in the Atlantic Forest and six in the Caatinga. A new species has been recorded to science, G. entomophilum, other as a first record for Brazil, G. morganii, six new records for the Northeast, and ten new records for Rio Grande do Norte. The material was tumbled in the Herbarium UFRN. Additionally, a survey of the species of the genus deposited in the Herbarium UFRN was accomplished, resulting in 244 herbarium specimens belonging to thirty-three species. Of these ones, twenty-three were collected in Brazil and ten are from Czech Republic, Europe, as donation from the VZ Herbarium

Conventional and Doppler ultrasound for the differentiation of benign and malignant canine mammary tumours

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of accelerated aging on the microhardness and color stability of flexible resins for dentures

Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins present advantages in terms of esthetics and comfort, studies assessing chromatic and microhardness alterations of these materials are still scarce in the related literature. The aim of this study was to evaluate the chromatic and microhardness alterations of two commercial brands of flexible resins in comparison to the conventional resin Triplex when submitted to accelerated aging. The resins were manipulated according to manufacturers' instructions and inserted into a silicone matrix to obtain 21 specimens divided into 3 groups: Triplex, Ppflex and Valplast. Triplex presented the highest microhardness value (p < 0.05) for all the aging periods, which was significantly different from that of the other resins, followed by the values of Valplast and Ppflex. Comparison between the flexible resins (Ppflex and Valplast) revealed a statistically significant difference (p < 0.05) as regards color. The flexible resin Ppflex and the conventional resin Triplex presented no statistically significant difference (p < 0.05) as regards aging. The accelerated aging significantly increased the microhardness values of the resins, with the highest values being observed for Triplex. Valplast presented the greatest chromatic alteration after accelerated aging.

Presence of a human diarrheagenic escherichia coli clone in captivity kept psittacidaes

Bacterial cultures of cloaca swabs from 86 captivity kept psittacidaes revealed 17 Escherichia coli bearing birds sharing strains which, on the basis of enterobacterial repetitive intergenic consensus (ERIC) PCR analysis, proved to be genetically similar. Further, triplex PCR specific for the genetic markers chuA, yjaA, and TSPE4.C2 was used to assign the strains to the E. coli reference collection (EcoR) B2 group. One strain of each, from the enteropathogenic (EPEC), enteroaggregative (EAEC) and Shiga toxin (STEC) E. coli pathovars were found among these isolates. © Marietto-Gonçalves et al.; Licensee Bentham Open.

Doppler ultrasonography principles and methods of evaluation of the reproductive tract in mares

Background: Doppler ultrasonography is a non-invasive real time pulse-wave technique recently used for the transrectal study of the reproductive system hemodynamics in large animals. This technic is based in the Doppler Effect Principle that proposes the change in frequency of a wave for an observer (red blood cells) moving relative to the source of the respective wave (ultrasonic transducer). This method had showed to be effective and useful for the evaluation of the in vivo equine reproductive tract increasing the diagnostic, monitoring, and predictive capabilities of theriogenology in mares. However, an accurate and truthful ultrasonic exam requires the previous knowledge of the Doppler ultrasonography principles. Review: In recent years, the capabilities of ultrasound flow imaging have increased enormously. The current Doppler ultrasound machines offer three methods of evaluation that may be used simultaneously (triplex mode). In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the tissue that can be viewed as a two-dimensional gray-scale image on screen. This mode is primarily used to identify anatomically a structure for its posterior evaluation using colored ultrasound modes (Color or Spectral modes). Colored ultrasound images of flow, whether Color or Spectral modes, are essentially obtained from measurements of moving red cells. In Color mode, velocity information is presented as a color coded overlay on top of a B-mode image, while Pulsed Wave Doppler provides a measure of the changing velocity throughout the cardiac cycle and the distribution of velocities in the sample volume represented by a spectral graphic. Color images conception varies according to the Doppler Frequency that is the difference between the frequency of received echoes by moving blood red cells and wave frequency transmitted by the transducer. To produce an adequate spectral graphic it is important determine the position and size of the simple gate. Furthermore, blood flow velocity measurement is influence by the intersection angle between ultrasonic pulses and the direction of moving blood-red cells (Doppler angle). Objectively colored ultrasound exam may be done on large arteries of the reproductive tract, as uterine and ovary arteries, or directly on the target tissue (follicle, for example). Mesovarium and mesometrium attachment arteries also can be used for spectral evaluation of the equine reproductive system. Subjectively analysis of the ovarian and uterine vascular perfusion must be done directly on the corpus luteum, follicular wall and uterus (endometrium and myometrium associated), respectively. Power-flow imaging has greater sensitivity to weak blood flow and independent of the Doppler angle, improving the evaluation of vessels with small diameters and slow blood flow. Conclusion: Doppler ultrasonography principles, methods of evaluation and reproductive system anatomy have been described. This knowledge is essential for the competent equipment acquisition and precise collection and analysis of colored ultrasound images. Otherwise, the reporting of inconsistent and not reproducible findings may result in the discredit of Doppler technology ahead of the scientific veterinary community.