Suchergebnisse

An extensive collection of Spanish maize was subjectively classified into 20 races and 32 intermediate varieties using morphological and agronomic data. Five of those 32 varieties were lost, and the remaining 47 populations are maintained at the Misión Biológica de Galicia. The objectives of the present study were to investigate the isozyme variation and the historical relationships of the Spanish maize races and intermediate varieties. Eleven isozyme systems encoded by 20 loci (15 polymorphic) were used to classify 20 races and 27 intermediate varieties. The isozyme classification showed that the intermediate varieties did not cluster together with their corresponding main races. Twenty-seven of the 47 populations originated from a single geographic area. Thus, a second isozyme classification was made for these 27 populations to investigate the relationships between the isozyme classification and the variability expected from historical records. The isozyme classification presented five to ten clusters. The first introductions of maize from the West Indies came to southern Spain and had little success. Guatemalan maize was more successful in the South of Spain and appears to have expanded to the East. South American maize had less influence in Spain than North American maize. North American maize was well established in the North and Northwest of Spain around the 17th Century, and it kept coming during the succeeding Centuries, including hybrids of the modern race Corn Belt Dent. The conclusions are (1) the classification of Spanish maize into 20 races and 27 intermediate varieties does not appear to reflect the structure of the variability of Spanish maize, and (2) maize came to Spain from all over the Americas, mainly from Central America at the beginning and from North America during the last four centuries. Although most of the primitive introductions may have been lost, some remain in our collection of local maize varieties; these represent a unique set of tropical to temperate populations adapted to temperate European conditions. ; Research supported by the European Union (Project RESGEN-CT96-88). ; Peer reviewed

Several theories have been advanced to explain the origin of European maize (Zen mays L.) based on history, yet neither the introduction of this crop, nor the variability among European populations, have been extensively studied until recently. The aim of the present investigation was to relate isozyme variation in European maize populations to the introduction of the species on this continent. Ten isozyme systems encoded by 19 loci were used to classify 404 maize open-pollinated populations from six European countries. The average number of alleles per locus in the collection was 3.1. Allele richness was quite homogeneous across countries. The distribution of rare alleles supports the historical conclusion that Spain was the main entrance of maize to Europe. Alleles shared by maize from Mediterranean countries and Mexico or Guatemala sugggest that the source of Mediterranean maize could have been these areas of Central America. Some rare alleles absent in Spain suggest that maize was also introduced through other countries. The collection of European populations was classified into two main groups, the smaller containing those of Northern Europe and the larger divided into Mediterranean and miscellaneous subgroups. Several singularities were seen that might be explained by drift or particular introductions. The results suggest that maize from North America came to Europe via the European Atlantic coast, and from Central America to the Mediterranean region, though introduction through other ways cannot be discarded on the basis of the present isozyme data. ; Research supported by the European Union (Project RESGEN-CT96-88) ; Peer reviewed

Can Chen,1,2,* Ting Wang,1,3,* Fengbo Wu,1,* Wei Huang,4 Gu He,1 Liang Ouyang,1 Mingli Xiang,1 Cheng Peng,4 Qinglin Jiang1,2 1State Key Laboratory of Biotherapy and Department of Pharmacy, West China Hospital, Sichuan University, Chengdu, 2College of Pharmacy and the First Affiliated Hospital, Chengdu Medical College, Chengdu, 3Department of Cardiology, Genenal Hospital of Chengdu Military Command, Chengdu, 4State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine, Chengdu University of Traditional Chinese Medicine, Chengdu, People's Republic of China*These authors contributed equally to this workAbstract: Compared with normal differentiated cells, cancer cells upregulate the expression of pyruvate kinase isozyme M2 (PKM2) to support glycolytic intermediates for anabolic processes, including the synthesis of nucleic acids, amino acids, and lipids. In this study, a combination of the structure-based pharmacophore modeling and a hybrid protocol of virtual screening methods comprised of pharmacophore model-based virtual screening, docking-based virtual screening, and in silico ADMET (absorption, distribution, metabolism, excretion and toxicity) analysis were used to retrieve novel PKM2 activators from commercially available chemical databases. Tetrahydroquinoline derivatives were identified as potential scaffolds of PKM2 activators. Thus, the hybrid virtual screening approach was applied to screen the focused tetrahydroquinoline derivatives embedded in the ZINC database. Six hit compounds were selected from the final hits and experimental studies were then performed. Compound 8 displayed a potent inhibitory effect on human lung cancer cells. Following treatment with Compound 8, cell viability, apoptosis, and reactive oxygen species (ROS) production were examined in A549 cells. Finally, we evaluated the effects of Compound 8 on mice xenograft tumor models in vivo. These results may provide important information for further research on novel PKM2 activators as antitumor agents.Keywords: pharmacophore, molecular docking, pyruvate kinase, virtual screening