1.
Lethin, Johanna, et al.
(författare)
Development and characterization of an EMS-mutagenized wheat population and identification of salt-tolerant wheat lines
2020
Ingår i: Bmc Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 20:1
Tidskriftsartikel (refereegranskat) abstract
Background Triticum aestivum (wheat) is one of the world's oldest crops and has been used for >8000 years as a food crop in North Africa, West Asia and Europe. Today, wheat is one of the most important sources of grain for humans, and is cultivated on greater areas of land than any other crop. As the human population increases and soil salinity becomes more prevalent, there is increased pressure on wheat breeders to develop salt-tolerant varieties in order to meet growing demands for yield and grain quality. Here we developed a mutant wheat population using the moderately salt-tolerant Bangladeshi variety BARI Gom-25, with the primary goal of further increasing salt tolerance. Results After titrating the optimal ethyl methanesulfonate (EMS) concentration, ca 30,000 seeds were treated with 1% EMS, and 1676 lines, all originating from single seeds, survived through the first four generations. Most mutagenized lines showed a similar phenotype to BARI Gom-25, although visual differences such as dwarfing, giant plants, early and late flowering and altered leaf morphology were seen in some lines. By developing an assay for salt tolerance, and by screening the mutagenized population, we identified 70 lines exhibiting increased salt tolerance. The selected lines typically showed a 70% germination rate on filter paper soaked in 200 mM NaCl, compared to 0-30% for BARI Gom-25. From two of the salt-tolerant OlsAro lines (OA42 and OA70), genomic DNA was sequenced to 15x times coverage. A comparative analysis against the BARI Gom-25 genomic sequence identified a total of 683,201 (OA42), and 768,954 (OA70) SNPs distributed throughout the three sub-genomes (A, B and D). The mutation frequency was determined to be approximately one per 20,000 bp. All the 70 selected salt-tolerant lines were tested for root growth in the laboratory, and under saline field conditions in Bangladesh. The results showed that all the lines selected for tolerance showed a better salt tolerance phenotype than both BARI Gom-25 and other local wheat varieties tested. Conclusion The mutant wheat population developed here will be a valuable resource in the development of novel salt-tolerant varieties for the benefit of saline farming.
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Abbas, Syed Adeel, et al.
(författare)
Spinel-type Na2MoO4 and Na2WO4 as promising optoelectronic materials : First-principle DFT calculations
2020
Ingår i: Chemical Physics. - : Elsevier. - 0301-0104 .- 1873-4421. ; 538
Tidskriftsartikel (refereegranskat) abstract
The mechanical, thermodynamic, electronic, and optical properties of Na2MoO4 (NMO) and Na2WO4 (NWO) spinels are elaborated by density functional theory (DFT) based full potential augmented plane wave method (FP-LAPW + lo). Our optimized lattice constants for the studied spinels are in good agreement with that obtained experimentally. The enthalpy of formation ensures the thermodynamic stability of NMO and NWO in the cubic phase. The Born mechanical stability criteria guarantees their mechanical stability, while Poisson ratio (ν) and Pugh's ratio (B/G) infer their brittle behavior. The Debye temperature (θD) is significant for NMO than NWO. The wide bandgap of 3.5 eV for NMO and 4.4 eV for NWO show the maximum absorption in the ultraviolet region that increases their importance for optoelectronic applications. The optical properties are explained in term of dielectric constant, refractive index, absorption of light, reflection, and optical loss factor.
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Hudson, Alan G., et al.
(författare)
Genomic signatures of relaxed disruptive selection associated with speciation reversal in whitefish
2013
Ingår i: BMC Evolutionary Biology. - : BioMed Central. - 1471-2148. ; 13, s. 108-
Tidskriftsartikel (refereegranskat) abstract
Background: Speciation reversal: the erosion of species differentiation via an increase in introgressive hybridization due to the weakening of previously divergent selection regimes, is thought to be an important, yet poorly understood, driver of biodiversity loss. Our study system, the Alpine whitefish (Coregonus spp.) species complex is a classic example of a recent postglacial adaptive radiation: forming an array of endemic lake flocks, with the independent origination of similar ecotypes among flocks. However, many of the lakes of the Alpine radiation have been seriously impacted by anthropogenic nutrient enrichment, resulting in a collapse in neutral genetic and phenotypic differentiation within the most polluted lakes. Here we investigate the effects of eutrophication on the selective forces that have shaped this radiation, using population genomics. We studied eight sympatric species assemblages belonging to five independent parallel adaptive radiations, and one species pair in secondary contact. We used AFLP markers, and applied F-ST outlier (BAYESCAN, DFDIST) and logistic regression analyses (MATSAM), to identify candidate regions for disruptive selection in the genome and their associations with adaptive traits within each lake flock. The number of outlier and adaptive trait associated loci identified per lake were then regressed against two variables (historical phosphorus concentration and contemporary oxygen concentration) representing the strength of eutrophication. Results: Whilst we identify disruptive selection candidate regions in all lake flocks, we find similar trends, across analysis methods, towards fewer disruptive selection candidate regions and fewer adaptive trait/candidate loci associations in the more polluted lakes. Conclusions: Weakened disruptive selection and a concomitant breakdown in reproductive isolating mechanisms in more polluted lakes has lead to increased gene flow between coexisting Alpine whitefish species. We hypothesize that the resulting higher rates of interspecific recombination reduce either the number or extent of genomic islands of divergence surrounding loci evolving under disruptive natural selection. This produces the negative trend seen in the number of selection candidate loci recovered during genome scans of whitefish species flocks, with increasing levels of anthropogenic eutrophication: as the likelihood decreases that AFLP restriction sites will fall within regions of heightened genomic divergence and therefore be classified as F-ST outlier loci. This study explores for the first time the potential effects of human-mediated relaxation of disruptive selection on heterogeneous genomic divergence between coexisting species.
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Michailakis, Dimitris, et al.
(författare)
Dilemmas of Inclusive Education
2009
Ingår i: ALTER, European Journal of Disability Research. ; 3, s. 24-44
Tidskriftsartikel (refereegranskat)
10.
Roh, Chang-gyun, et al.
(författare)
A study on design criteria for slope walking facilities to reduce the aged's falling
2018
Konferensbidrag (refereegranskat) abstract
Ageing makes faster progress in Korean than any other countries, which has resulted in social problems including decrease in economic population and such phenomenon is not what happened in Korea alone. Japan where the ageing reaches a certain level has suffered social conflict and problem such as a generational conflict and the measure to deal with such problems has been sought.Such a social problem in ageing society is not limited to humanities and social sector. Generally the facilities and the standard in our society have been designed and built for the ordinary person (young adults) and thus the aged complains of the inconvenience when using the facilities which however are convenient and safe for the ordinary person. According to KICT (2017), most of the aged feels the physical inconvenience when using the stair, pedestrian overpass and ramp, pointing out particularly too many steps and a high kick plate (step height)According to the study on walking pattern of the aged on flat surface by Roh (2015), those who have a good physical condition or walking ability among the aged who can walk alone (without walking assistance device) accounts for 82% when comparing to the ordinary person. Among the aged who do not use the stick or walking assistance device, those who feel the inconvenience with walking is only 54% of the walking ability of the ordinary person. Falling accident is attributable to such poor walking ability (particularly dynamic balance ability and physical strength. The aged would surely feel more physical inconvenience when walking the stair or ramp than walking the flat surface and this study thus is intended to measure the walking pattern and physical conditions while the aged is walking the ramp and then develop the design factors and criteria for walking facilities based on data from the measurement, which would help prevent the falling or slipping by the aged while walking, thereby making commitment to reducing the resultant social and economic cost.
