High fidelity extrachromosomal recombination and gene targeting in plants

The precision of extrachromosomal homologous recombination and gene targeting in plant cells was investigated. Recombination was directed to introns of selectable marker genes where potential changes could persist without affecting the function and therefore the selectability of the genes. Approximately 9 kb of crossover regions was rescued and sequenced. Changes were detected at a frequency below one point mutation per 1000 bp, indicating that extrachromosomal recombination and gene targeting both appear to occur with high fidelity.     

In vitro pollen germination of species and two interspecific hybrids from the genus Brassica

In vitro pollen germination of five species and two interspecific hybrids from the genus Brassica was tested in four media. Genetically fixed differences in the demands for optimal pollen germination among species were found. The experiments were designed to define optimal content of mineral salts, sugar, and PEG for every investigated species or hybrids. The differences found among species are discussed in relation to the evolutionary trend.     

IMpRH server: an RH mapping server available on the Web

SUMMARY: The INRA-Minnesota Porcine Radiation Hybrid (IMpRH) Server provides both a mapping tool (IMpRH mapping tool) and a database (IMpRH database) of officially submitted results. The mapping tool permits the mapping of a new marker relatively to markers previously mapped on the IMpRH panel. The IMpRH database is the official database for submission of new results and queries. The database not only permits the sharing of public data but also semi-private and private data.     

Impact of Progerbalin LG® on the apple fruit physical attributes

During two consecutive years (2010 and 2011) we evaluated the impact of Progerbalin LG^® (mixture of gibberellins (GA₄₊₇) and N ⁶-benzyladenine) on fruit weight, fruit dimensions, elongation, geometric mean diameter or fruit size, aspect ratio, surface area and fruit volume of five apple cultivars belonging to ‘Red Delicious’ group (‘Hapke’ grafted on M.9 and M.26, ‘Hi Red’, ‘Starking’ and ‘Top Red’ on M.9, and ‘Red Chief Camspur’ on MM.106 rootstock). Trees were sprayed twice with 30, 50 or 100 ml L^?1 i.e. between 80 % of open flowers and the following petal fall (first treatment), and 10 days after first application (second treatment); control trees were not sprayed. Results showed that the lowest dose increased fruit weight in all cultivars, except ‘Top Red’ and ‘Red Chief Camspur’; this dose promoted fruit dimensions, fruit size and elongation in ‘Hapke’ on both rootstocks, and also fruit dimensions, surface area and fruit volume in ‘Hi Red’. Regarding ‘Starking’, different doses of Progerbalin LG^® did not affect other properties evaluated, but season played an important role in these cases. In contrast, the highest dose of this hormone improved all physical attributes in ‘Top Red’ and ‘Red Chief Camspur’, except elongation and/or aspect ratio. In some cases, good values were found in control treatment.     

Neural differentiation of mouse embryonic stem cells grown in monolayer

To drive neural differentiation of mouse embryonic stem (ES) cells, various culture protocols have been previously developed that all require the formation of embryoid bodies, usually combined with a treatment by all-trans retinoic acid (aRA). Here, we investigated whether or not neural differentiation can also occur in a simplified monolayer culture. Mouse ES cells were plated in serum-containing DMEM media with and without aRA and grown under these conditions for 2 days. Then, the cells were transferred to fresh serum-containing DMEM media and/or to serum-free DMEM/F12 media supplemented with a mixture of insulin, transferrin, selenium, and fibronectin (ITSF) for further culture. The changes in cell morphology and in the expression of selected molecular markers were monitored. Generally, in contrast to all the others, the protocol consisting of a 2-day culture in serum-containing DMEM followed by continuous exposure to the ITSF supplement in DMEM/F12 drove a vast majority of ES cells to generate phenotypic signs of neural lineage. Altogether, neural differentiation can be achieved in vitro without the step involving the formation of embryoid bodies as well as the treatment by aRA.