A single polyploidization event at the origin of the tetraploid genome of Coffea arabica is responsible for the extremely low genetic variation in wild and cultivated germplasm

The genome of the allotetraploid species Coffea arabica L. was sequenced to assemble independently the two component subgenomes (putatively deriving from C. canephora and C. eugenioides) and to perform a genome-wide analysis of the genetic diversity in cultivated coffee germplasm and in wild populations growing in the center of origin of the species. We assembled a total length of 1.536 Gbp, 444 Mb and 527 Mb of which were assigned to the canephora and eugenioides subgenomes, respectively, and predicted 46,562 gene models, 21,254 and 22,888 of which were assigned to the canephora and to the eugeniodes subgenome, respectively. Through a genome-wide SNP genotyping of 736 C. arabica accessions, we analyzed the genetic diversity in the species and its relationship with geographic distribution and historical records. We observed a weak population structure due to low-frequency derived alleles and highly negative values of Taijma's D, suggesting a recent and severe bottleneck, most likely resulting from a single event of polyploidization, not only for the cultivated germplasm but also for the entire species. This conclusion is strongly supported by forward simulations of mutation accumulation. However, PCA revealed a cline of genetic diversity reflecting a west-to-east geographical distribution from the center of origin in East Africa to the Arabian Peninsula. The extremely low levels of variation observed in the species, as a consequence of the polyploidization event, make the exploitation of diversity within the species for breeding purposes less interesting than in most crop species and stress the need for introgression of new variability from the diploid progenitors

Assembly of small molecule surfactants at highly dynamic air-water interfaces

Small-angle neutron scattering has been used to probe the interfacial structure of foams stabilised by small molecule surfactants at concentrations well below their critical micelle concentration. The data for wet foams showed a pronounced Q−4 dependence at low Q and noticeable inflexions over the mid Q range. These features were found to be dependent on the surfactant structure (mainly the alkyl chain length) with various inflexions across the measured Q range as a function of the chain length but independent of factors such as concentration and foam age/height. By contrast, foam stability (for C < CMC) was significantly different at this experimental range. Drained foams showed different yet equally characteristic features, including additional peaks attributed to the formation of classical micellar structures. Together, these features suggest the dynamic air–water interface is not as simple as often depicted, indeed the data have been successfully described by a model consisting paracrystalline stacks (multilayer) of adsorbed surfactant layers; a structure that we believe is induced by the dynamic nature of the air–water interface in a foam

Transformation and tumorigenicity testing of simian cell lines and evaluation of poliovirus replication

The key role of cell cultures in different scientific fields is worldwide recognized, both as in vitro research models alternative to laboratory animals and substrates for biological production. However, many safety concerns rise from the use of animal/human cell lines that may be tumorigenic, leading to potential adverse contaminations in cell-derived biologicals. In order to evaluate the suitability of 13 different cell lines for Poliovirus vaccine production, safety and quality, in vitro/in vivo tumorigenicity and Poliovirus propagation properties were evaluated. Our results revealed that non-human primate cell lines CYNOM-K1, FRhK-4, 4MBr-5 and 4647 are free of tumorigenic features and represent highly susceptible substrates for attenuated Sabin Poliovirus strains. In particular, FRhK-4 and 4647 cell lines are characterized by a higher in vitro replication, resulting indicated for the use in large-scale production field

Investigation of Chernobyl 4-th unit materials by gamma activation method

Isotope and element content the samples of Chornobyl 4-th wrecking unit materials (concrete fragments and lava-like materials) were investigated by γ-activation method using bremsstrahlung of the electron accelerator. The concentration of a number of nuclides (U-238, Cs-137, Sr-90, Ni-58, Zr-90 etc.) and their depth distribution into concrete were determined as well as the corresponding correlation ratio. The comparison of the obtained data with the structure-phase analysis results was carried out

Performance of Coffea arabica F1 hybrids in agroforestry and full-sun cropping systems in comparison with American pure line cultivars

Coffea arabica F1 hybrids derived from crosses between wild Sudan-Ethiopian and American cultivars and propagated by somatic embryogenesis have been obtained in Central America. These new hybrids considerably enhanced the genetic diversity of coffee in the region. We conducted 15 trials to assess whether using hybrids represents substantial genetic progress in terms of productivity in agroforestry and full-sun cropping systems. The new germplasm was grown in the same conditions as the best American cultivar (homozygous pure lines). The results showed that yields of hybrids were earlier and superior to those of American cultivars. The hybrids were also more stable than the American cultivars in all environments. In the agroforestry system, the mean yield of hybrids was 58% higher than that of the American cultivars, while the mean yield of hybrids in the full-sun system was 34% higher. Coffee-based agroforestry systems (AS) are considered effective in protecting the environment in the volcanic cordilleras of Central America. We found that introducing hybrids in coffee-based AS can considerably increase productivity. This finding could be a convincing argument to encourage coffee growers who have adopted the full-sun cropping system to return to agroforestry cropping systems. Finally, the conditions for large-scale dissemination of those new hybrids—which represent a major innovation for C. arabica cropping—was analysed