Molecular dissection of the pea shoot apical meristem*

The shoot apical meristem (SAM) is responsible for the development of all the above-ground parts of a plant. Our understanding of the SAM at the molecular level is incomplete. This study investigates the gene expression repertoire of SAMs in the garden pea (Pisum sativum). To this end, 10 346 EST sequences representing 7610 unique genes were generated from SAM cDNA libraries. These sequences, together with previously reported pea ESTs, were used to construct a 12K oligonucleotide array to identify genes with differential SAM expression, as compared to axillary meristems, root apical meristems, or non-meristematic tissues. A number of genes were identified, predominantly expressed in specific cell layers or domains of the SAM and thus are likely components of the gene networks involved in stem cell maintenance or the initiation of lateral organs. Further in situ hybridization analysis confirmed the spatial localization of some of these genes within the SAM. Our data also indicate the diversification of some gene expression patterns and hence functions in legume crop plants. A number of transcripts highly expressed in all three meristems have also been uncovered and these candidates may provide valuable insight into molecular networks that underpin the maintenance of meristematic functionality

Electrochemical analysis of microdroplet formation

This paper reports an electrochemical measurement system with a high-speed camera for observation of molecular transport phenomena at a water-oil (W/O) interface during microfluidic droplet formation. For demonstration of the system, currents corresponding to the transport of electrolyte ions to form the electrical double layer at the liquid interface were measured. Additionally, the high-speed camera observation revealed charge-effect on droplet stability during and/or just after the formation. This measurement system is expected to facilitate a full understanding of the droplet formation process

Dual-view flow channel visualization

The concept of dual-view flow-channel visualization is proposed, where ordinary (top) and lateral images are available in a single view field. In order to obtain the top and lateral fluidic-channel images in a single view of the microscope observation, optical path lengths of these images were compensated by additional adjusting PDMS layer. In the transillumination observation, the lateral dark-field image and the top bright-field images were obtained simultaneously. The dual-view fluorescent observation of cultured HUVEC was also demonstrated