The organs of multicellular species consist of cell types that must function together to perform specific tasks. One critical organ function is responding to internal or external change. Some cellspecific responses to changes in environmental conditions are known, but the scale of cell-specific responses within an entire organ as it perceives an environmental flux has not been well characterized in plants or any other multicellular organism. Here, we use cellular profiling of five Arabidopsis root cell types in response to an influx of a critical resource, nitrogen, to uncover a vast and predominantly cell-specific response. We show that cellspecific profiling increases sensitivity several-fold, revealing highly localized regulation of transcripts that were largely hidden from previous global analyses. The cell-specific data revealed responses that suggested a coordinated developmental response in distinct cell types or tissues. One example is the cell-specific regulation of a transcriptional circuit that we showed mediates lateral root outgrowth in response to nitrogen via microRNA167, linking small RNAs to nitrogen responses. Together, these results reveal a previously cryptic component of cell-specific responses to nitrogen. Thus, the results make an important advance in our understanding of how multicellular organisms cope with environmental change at the cell level.cell sorting ͉ microRNA ͉ lateral roots ͉ auxin response ͉ transcriptional analysis

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Carbon and nitrogen signaling in Arabidopsis

Qualitative network models and genome-wide expression data define carbon/nitrogen-responsive molecular machines in Arabi-dopsis and indicate that regulation by carbon/nitrogen metabolites occurs at multiple levels.

Prokaryotic species classification has lagged dramatically behind eukaryotic species due to the dependence on the difficult DNA-DNA hybridization technique required for species designation. This is disadvantageous for the general understanding of the diversity of microbial life and unique microorganisms, along with their metabolic abilities, like bioremediation of hazardous waste. This applies to the secondary metabolites microorganisms produce that can be beneficial for humans and other living organisms, such as antibiotics or other industrially important compounds. In an effort to isolate and identify new microbial species, environmental samples were collected from marine sediment environments as marine habitats are under-sampled compared to non-marine habitats. Two marine isolates designated MI-1 and MI-2 were isolated from marine sediment environments off the Gulf Coast of Florida and chosen for further study because of their antibacterial production and unique colony pigmentation. They were genetically analyzed through sequencing of the 16s rRNA gene, shotgun cloning, and an eight-gene multi-locus sequence analysis comparison to 66 other species of the same genus. From these, MI-1 and MI-2 can be classified as members of the Vibrio genus most closely related to Vibrio ruber and a distinct strain from V. ruber type strain VR-1.