The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of ...The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was of ten associated with increased chromosome numbers, but some of the variant seedlings were karyotypically indistinguishable from Raki or C39. Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation (aneusomaty). In one of the SC2seedlings, the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10. The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings, with a chromosome number of about 70, were genetically unstable. Of 11 SC2 seedlings examined cytolog ically, 6 did not produce any viable seed. Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation. SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent. Some of the SC3 seedlings exhibited an even wider range of chromosome numbers (e.g.56-136), and these plants were all dwarfs.展开更多
Mathematical modelling of cellular metabolism plays an important role in understandingbiological functions and providing identification of targets for biotechnological modification.This paperproposes a nonlinear bilev...Mathematical modelling of cellular metabolism plays an important role in understandingbiological functions and providing identification of targets for biotechnological modification.This paperproposes a nonlinear bilevel programming(NBP)model to infer the objective function of anaerobicglycerol metabolism in Klebsiella Pneumoniae(K.Pneumoniae)for 1,3-propanediol(1,3-PD)production.Based on the Kuhn-Tucker optimality condition of the lower level problem,NBP is transformedinto a nonlinear programming with complementary and slackness conditions.The authors give the existencetheorem of solutions to NBP.An efficient algorithm is proposed to solve NBP and its convergenceis also simply analyzed.Numerical results reveal some interesting conclusions,e.g.,biomass productionis the main force to drive glycerol metabolism,and the objective functions,which are obtained in termof several different groups of flux distributions,are similar.展开更多
With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into ...With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.展开更多
文摘The somaclone, C39, derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki (2n=50), had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was of ten associated with increased chromosome numbers, but some of the variant seedlings were karyotypically indistinguishable from Raki or C39. Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation (aneusomaty). In one of the SC2seedlings, the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10. The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings, with a chromosome number of about 70, were genetically unstable. Of 11 SC2 seedlings examined cytolog ically, 6 did not produce any viable seed. Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation. SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent. Some of the SC3 seedlings exhibited an even wider range of chromosome numbers (e.g.56-136), and these plants were all dwarfs.
基金supported by the National Natural Science Foundation of China under Grant Nos.10871033 and 10671126
文摘Mathematical modelling of cellular metabolism plays an important role in understandingbiological functions and providing identification of targets for biotechnological modification.This paperproposes a nonlinear bilevel programming(NBP)model to infer the objective function of anaerobicglycerol metabolism in Klebsiella Pneumoniae(K.Pneumoniae)for 1,3-propanediol(1,3-PD)production.Based on the Kuhn-Tucker optimality condition of the lower level problem,NBP is transformedinto a nonlinear programming with complementary and slackness conditions.The authors give the existencetheorem of solutions to NBP.An efficient algorithm is proposed to solve NBP and its convergenceis also simply analyzed.Numerical results reveal some interesting conclusions,e.g.,biomass productionis the main force to drive glycerol metabolism,and the objective functions,which are obtained in termof several different groups of flux distributions,are similar.
基金supported by the National Basic Research Program of China(2013CB733801)the National Key Research and Development Program of China(2017YFA0104301)thankful to the supports from the Fundamental Research Funds for the Central Universities
文摘With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.
