980 research outputs found

    Genetic variability of Taenia saginata inferred from mitochondrial DNA sequences

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    Taenia saginata is an important tapeworm, infecting humans in many parts of the world. The present study was undertaken to identify inter- and intraspecific variation of T. saginata isolated from cattle in different parts of Iran using two mitochondrial CO1 and 12S rRNA genes. Up to 105 bovine specimens of T. saginata were collected from 20 slaughterhouses in three provinces of Iran. DNA were extracted from the metacestode Cysticercus bovis. After PCR amplification, sequencing of CO1 and 12S rRNA genes were carried out and two phylogenetic analyses of the sequence data were generated by Bayesian inference on CO1 and 12S rRNA sequences. Sequence analyses of CO1 and 12S rRNA genes showed 11 and 29 representative profiles respectively. The level of pairwise nucleotide variation between individual haplotypes of CO1 gene was 0.3–2.4 % while the overall nucleotide variation among all 11 haplotypes was 4.6 %. For 12S rRNA sequence data, level of pairwise nucleotide variation was 0.2–2.5 % and the overall nucleotide variation was determined as 5.8 % among 29 haplotypes of 12S rRNA gene. Considerable genetic diversity was found in both mitochondrial genes particularly in 12S rRNA gene. © 2015, Springer-Verlag Berlin Heidelberg

    Remodeling by fibroblasts alters the rate-dependent mechanical properties of collagen

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    The ways that fibroblasts remodel their environment are central to wound healing, development of musculoskeletal tissues, and progression of pathologies such as fibrosis. However, the changes that fibroblasts make to the material around them and the mechanical consequences of these changes have proven difficult to quantify, especially in realistic, viscoelastic three-dimensional culture environments, leaving a critical need for quantitative data. Here, we observed the mechanisms and quantified the mechanical effects of fibroblast remodeling in engineered tissue constructs (ETCs) comprised of reconstituted rat tail (type I) collagen and human fibroblast cells. To study the effects of remodeling on tissue mechanics, stress-relaxation tests were performed on ETCs cultured for 24, 48, and 72 h. ETCs were treated with deoxycholate and tested again to assess the ECM response. Viscoelastic relaxation spectra were obtained using the generalized Maxwell model. Cells exhibited viscoelastic damping at two finite time constants over which the ECM showed little damping, approximately 0.2 s and 10-30 s. Different finite time constants in the range of 1-7000 s were attributed to ECM relaxation. Cells remodeled the ECM to produce a relaxation time constant on the order of 7000 s, and to merge relaxation finite time constants in the 0.5-2 s range into a single time content in the 1 s range. Results shed light on hierarchical deformation mechanisms in tissues, and on pathologies related to collagen relaxation such as diastolic dysfunction. Statement of Significance As fibroblasts proliferate within and remodel a tissue, they change the tissue mechanically. Quantifying these changes is critical for understanding wound healing and the development of pathologies such as cardiac fibrosis. Here, we characterize for the first time the spectrum of viscoelastic (rate-dependent) changes arising from the remodeling of reconstituted collagen by fibroblasts. The method also provides estimates of the viscoelastic spectra of fibroblasts within a three-dimensional culture environment. Results are of particular interest because of the ways that fibroblasts alter the mechanical response of collagen at loading frequencies associated with cardiac contraction in humans. © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

    Bonding, bridging and linking social capital and psychological empowerment among squatter settlements in Tehran, Iran

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    This study aims to determine the effect of bonding, bridging and linking social capital in the psychological empowerment among squatter settlements in Tehran, Iran. The sample comprised 328 poor people in two communities from Iran, which were randomly selected for the study. A self-administered questionnaire was used as the data collection method and the stratified random sampling technique was employed. The results revealed the significant effect of bonding, bridging and linking social capital on psychological empowerment among squatter settlements. Bonding social capital had the largest beta coefficient than other dimensions, such as bridging and linking social capital in predicting psychological empowerment among squatter settlements

    Molecular population study on Penaeus semisulcatus from the Persian Gulf and Oman Sea using cytochrom oxidase subunit I (COI) gene by RFLP method

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    The objective of this investigation was molecular population study on Penaeus semisulcatus stocks from the Persian Gulf and Oman Sea. Samples were collected using trawling method from Hormuz (40 individuals) and Bushehr (35 individuals) regions. The DNA of samples were extracted using phenol and chloroform method and then were simplified using a pair premier of Cytochrom Oxidase Subunit I (COI) gene sequence by a thermal cycler. Nine restriction enzyme were Used to digest the larger gene region that five of them (Alu I, Hinf I, Hinc I I, Hpa I I and Rca I) appeared Polymorphic patterns. Reap software and X^2 test were used to analyses the RFLP data. The average nucleotide diversity arid haplotype diversity among the population were 0.0345720 ± 0.0011952 and 0.28590±0.08174 and nucleotide divergence among population, being studied, is supposed to be 8.5%. Considering the result dispersion of haplotypes in two region showed a significant difference and this is an evidence for proving the variety of the stocks

    Molecular and morphological characterization of the tapeworm Taenia hydatigena (Pallas, 1766) in sheep from Iran

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    Although Taenia hydatigena is one of the most prevalent taeniid species of livestock, very little molecular genetic information exists for this parasite. Up to 100 sheep isolates of T. hydatigena were collected from 19 abattoirs located in the provinces of Tehran, Alborz and Kerman. A calibrated microscope was used to measure the larval rostellar hook lengths. Following DNA extraction, fragments of cytochrome c oxidase 1 (CO1) and 12S rRNA genes were amplified by the polymerase chain reaction method and the amplicons were subjected to sequencing. The mean total length of large and small hooks was 203.4 μm and 135.9 μm, respectively. Forty CO1 and 39 12S rRNA sequence haplotypes were obtained in the study. The levels of pairwise nucleotide variation between individual haplotypes of CO1 and 12S rRNA genes were determined to be between 0.3-3.4% and 0.2-2.1%, respectively. The overall nucleotide variation among all the CO1 haplotypes was 9.7%, and for all the 12S rRNA haplotypes it was 10.1%. A significant difference was observed between rostellar hook morphometry and both CO1 and 12S rRNA sequence variability. A significantly high level of genetic variation was observed in the present study. The results showed that the 12S rRNA gene is more variable than CO1. © 2013 Cambridge University Press

    Magnetomotive drive and detection of clamped-clamped mechanical resonators in water

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    We demonstrate magnetomotive drive and detection of doubly clamped string resonators in water. A compact 1.9 T permanent magnet is used to detect the fundamental and higher flexural modes of 200μm\mathrm{200 \mu m} long resonators. Good agreement is found between the magnetomotive measurements and optical measurements performed on the same resonator. The magnetomotive detection scheme can be used to simultaneously drive and detect multiple sensors or scanning probes in viscous fluids without alignment of detector beams.Comment: 4 pages, 3 figure

    Molecular Identification and Sequencing of Mannose Binding Protein (MBP) Gene of Acanthamoeba palestinensis

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    "nBackground: Acanthamoeba keratitis develops by pathogenic Acanthamoeba such as A. pal­es­tinen­sis. Indeed this species is one of the known causative agents of amoebic keratitis in Iran. Mannose Binding Protein (MBP) is the main pathogenicity factors for developing this sight threatening disease. We aimed to characterize MBP gene in pathogenic Acanthamoeba isolates such as A. palestinensis."nMethods: This experimental research was performed in the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran during 2007-2008.  A. palestinensis was grown on 2% non-nutrient agar overlaid with Escherichia coli. DNA extraction was performed using phenol-chloroform method. PCR reaction and amplification were done using specific primer pairs of MBP. The amplified fragment were purified and sequenced. Finally, the obtained fragment was deposited in the gene data bank."nResults: A 900 bp PCR-product was recovered after PCR reaction. Sequence analysis of the purified PCR product revealed a gene with 943 nucleotides. Homology analysis of the ob­tained sequence showed 81% similarity with the available MBP gene in the gene data bank. The fragment was deposited in the gene data bank under accession number EU678895"nConclusion: MBP is known as the most important factor in Acanthamoeba pathogenesis cas­cade. Therefore, characterization of this gene can aid in developing better therapeutic agents and even immunization of high-risk people
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