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Maryam Gharehaghaji Emily S. Minor Mary V. Ashley Saji T. Abraham Walter D. Koenig 《Plant Ecology》2017,218(4):487-499
Landscape features affect habitat connectivity and patterns of gene flow and hence influence genetic structure among populations. We studied valley oak (Quercus lobata), a threatened species of California (USA) savannas and oak woodlands, with a distribution forming a ring around the Central Valley grasslands. Our main goal was to determine the role of topography and land cover on patterns of gene flow and to test whether elevation or land cover forms stronger barriers to gene flow among valley oak populations. We sampled valley oaks in 12 populations across the range of this species, genotyped each tree at eight nuclear microsatellite loci, and created a series of resistance surfaces by assigning different resistance values to land cover type and elevation. We also estimated recent migration rates and evaluated them with regard to landscape features. There was a significant but weak relationship between Euclidian distance and genetic distance. There was no relationship between genetic distances and land cover, but a significant relationship between genetic distances and elevation resistance. We conclude that gene flow is restricted by high elevations in the northern part of the valley oak range and by high elevations and the Central Valley further south. Migration rate analysis indicated some gene flow occurring east–west but we suggest that the high connectivity in the northern Central Valley is facilitating the formation of these links. We predict that southern populations may become more differentiated in the future through genetic isolation and local adaptation taking place in the face of climate change. 相似文献
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Azam Nikzad Gharehaghaji Kazem Arzani Hamid Abdollahi Abdolali Shojaeiyan Luca Dondini Paolo De Franceschi 《Tree Genetics & Genomes》2014,10(2):411-428
The Pyrus species exhibit the so-called S-RNase-based gametophytic self-incompatibility system, which is considered to be the most widespread self-incompatibility system among flowering plants. In this study, 57 Iranian pear (Pyrus communis L.) domestic cultivars and wild genotypes, plus 21 European pear cultivars used as references, were genotyped adopting a PCR-based genotyping assay using consensus and allele-specific primers. The results revealed traces of significant genetic contribution in the Iranian traditional varieties and genotypes from other Pyrus species; the genetic contribution of Japanese pear clearly emerged with the detection of some Pyrus pyrifolia S-RNase alleles. Moreover, our results highlighted the presence of three new S-RNase alleles (named S126, S127, and S128) that were not previously identified in P. communis, possibly introduced in the germplasm of cultivated pear through gene transfer from other cultivated or wild species. 相似文献
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Dieter Korn Abbas Ghaderi Nahideh Ghanizadeh Tabrizi Jana Gliwa 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2020,53(2):154-165
Occurrences of Late Permian coiled nautiloids are widespread but they have never been analysed in terms of spatial and temporal disparity changes. Morphometric analyses using the cardinal Raupian conch parameters: conch width index, umbilical width index and whorl expansion rate with subsequent analysis by using principal components analysis and non-metric multidimensional scaling, allow the construction of a nautiloid morphospace. The analyses show that there is a stable disparity in the coiled nautiloids from the Wuchiapingian to the Changhsingian. Differences between the three major Late Permian nautiloid occurrences (Salt Range, South China and Transcaucasus-NW Iran) are considerably small; the South Chinese occurrences, however, are characterized by many endemic genera. The most important variation in morphospace occupation is caused by environmental differences such as water depth. 相似文献
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Asghar Mesbahi Vahid Jafarzadeh Nahideh Gharehaghaji 《Reports of Practical Oncology and Radiotherapy》2012,17(3):146-150
Background
Application of less toxic normoxic polymer gel of N-isopropyl acrylamide (NIPAM) for radiation therapy has been studied in recent years.Aim
In the current study the optical and NMR properties of NIPAM were studied for radiation therapy dosimetry application.Materials and methods
NIPAM normoxic polymer gel was prepared and irradiated by 9 MV photon beam of a medical linac. The optical absorbance was measured using a conventional laboratory spectrophotometer in different wavelengths ranging from 390 to 860 nm. R2 measurements of NIPAM gels were performed using a 1.5 T scanner and R2–dose curve was obtained.Results
Our results showed R2 dose sensitivity of 0.193 ± 0.01 s−1 Gy−1 for NIPAM gel. Both R2 and optical absorbance showed a linear relationship with dose from 1.5 to 11 Gy for NIPAM gel dosimeter. Moreover, absorbance–dose response varied considerably with light wavelength and highest sensitivity was seen for the blue part of the spectrum.Conclusion
Our results showed that both optical and NMR approaches have acceptable sensitivity and accuracy for dose determination with NIPAM gel. However, for optical reading of the gel, utilization of an optimum optical wavelength is recommended. 相似文献5.
Hamideh Vaghari Hoda Jafarizadeh-Malmiri Mojgan Mohammadlou Aydin Berenjian Navideh Anarjan Nahideh Jafari Shahin Nasiri 《Biotechnology letters》2016,38(2):223-233
Immobilization of enzymes enhances their properties for efficient utilization in industrial processes. Magnetic nanoparticles, due to their high surface area, large surface-to-volume ratio and easy separation under external magnetic fields, are highly valued. Significant progress has been made to develop new catalytic systems that are immobilized onto magnetic nanocarriers. This review provides an overview of recent developments in enzyme immobilization and stabilization protocols using this technology. The current applications of immobilized enzymes based on magnetic nanoparticles are summarized and future growth prospects are discussed. Recommendations are also given for areas of future research. 相似文献
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