enod40 induces dedifferentiation and division of root cortical cells in legumes

Under nitrogen-limiting conditions Rhizobium meliloti can establish symbiosis with Medicago plants to form nitrogen-fixing root nodules. Nodule organogenesis starts with the dedifferentiation and division of root cortical cells. In these cells the early nodulin gene enod40, which encodes an unusually small peptide (12 or 13 amino acids), is induced from the beginning of this process. Herein we show that enod40 expression evokes root nodule initiation. (i) Nitrogen-deprived transgenic Medicago truncatula plants overexpressing enod40 exhibit extensive cortical cell division in their roots in the absence of Rhizobium. (ii) Bombardment of Medicago roots with an enod40-expressing DNA cassette induces dedifferentiation and division of cortical cells and the expression of another early nodulin gene, Msenod12A. Moreover, transient expression of either the enod40 region spanning the oligopeptide sequence or only the downstream region without this sequence induces these responses. Our results suggest that the cell-specific growth response elicited by enod40 is involved in the initiation of root nodule organogenesis.

Expression of a Hox gene, Cnox-2, and the division of labor in a colonial hydroid

We report the isolation and expression of the Hox gene, Cnox-2, in Hydractinia symbiolongicarpus, a hydrozoan displaying division of labor. We found different patterns of aboral-to-oral Cnox-2 expression among polyp polymorphs, and we show that experimental conversion of one polyp type to another is accompanied by concordant alteration in Cnox-2 expression. Our results are consistent with the suggestion that polyp polymorphism, characteristic of hydractiniid hydroids, arose via evolutionary modification of proportioning of head to body column.

Nanoscale imaging of chemical interactions: Fluorine on graphite

Using C60-functionalized scanning tunneling microscope tips, we have investigated the adsorption of fluorine on graphite. Based on characteristics of the accompanying electron standing waves, we are able to distinguish the fluorine adatoms that have bonded ionically to the graphite surface from those that have formed covalent bonds with the surface. This result permits determination of the ratio of ionic to covalent C–F bonds on graphite obtained by gas phase fluorination, which seems to be temperatureindependent between 200 and 300°C under the reaction conditions used.

ConfChem Conference on A Virtual Colloquium to Sustain and Celebrate IYC 2011 Initiatives in Global Chemical Education—The Global Experiment of the IYC2011: Creating Online Communities for Education and Science

The Global Experiment, Water: A Chemical Solution, was one of the flagship activities of the International Year of Chemistry (IYC). During the virtual colloquium of the spring 2012 online ConfChem conference, the main results of this year-long experiment were presented and discussed online for a week. Some of the main conclusions of the virtual conversations relate to the benefits of creating online communities of people sharing similar interests, the use of online educational platforms to gather massive amounts of data, and specific questions about the development of this IYC initiative. The activities of the global water experiment (GWE) were designed by a team of experts and the protocols are available online on the GWE Web site. The results were shown in one interactive world map that allowed students to learn about data visualization, validation, and interpretation. The feedback obtained from the participants of the GWE and later by the contributors of the virtual colloquium was very positive. Many participants asked specific and technical questions about the development of this experiment, while others excitedly endorsed the convenience of these large open-access activities to promote chemistry worldwide. The estimate is that over 2 million people took part in the GWE during the IYC. This communication summarizes one of the invited papers to the ConfChem online conference: A Virtual Colloquium to Sustain and Celebrate IYC 2011 Initiatives in Global Chemical Education, held from May 18 to June 29, 2012 and hosted by the ACS DivCHED Committee on Computers in Chemical Education and the IUPAC Committee on Chemistry Education.