Project description:Although N2 fixation can occur in free-living cyanobacteria, the unicellular endosymbiotic cyanobacterium Candidatus Atelocyanobacterium thalassa (UCYN-A) is considered to be a dominant N2-fixing species in marine ecosystems. Four UCYN-A sublineages are known from partial nitrogenase (nifH) gene sequences. However, few studies have investigated their habitat preferences and regulation by their respective hosts in open-ocean versus coastal environments. Here, we compared UCYN-A transcriptomes from oligotrophic open-ocean versus nutrient-rich coastal waters. UCYN-A1 metabolism was more impacted by habitat changes than UCYN-A2. However, across habitats and sublineages genes for nitrogen fixation and energy production were highly transcribed. Curiously these genes, critical to the symbiosis for the exchange of fixed nitrogen for fixed carbon, maintained the same schedule of diel expression across habitats and UCYN-A sublineages, including UCYN-A3 in the open-ocean transcriptomes. Our results undersore the importance of nitrogen fixation in UCYN-A symbioses across habitats, with consequences for community interaction and global biogeochemical cycles.
Project description:A custom multi-species microarray was used to study gene expression in wild hornyhead turbot (Pleuronichthys verticalis), collected from polluted and clean coastal waters in Southern California and in laboratory male zebrafish (Danio rerio) following exposure to estradiol and 4-nonylphenol. A multi-gene cross species microarray was fabricated as a diagnostic tool to screen the effects of environmental chemicals in fish, for which there is minimal genomic information. The microarray measurement of gene expression in zebrafish, which are phylogenetically distant from turbot, indicates that this multi-species microarray will be useful for measuring endocrine responses in Pleuronectiformes and other fish for which there is minimal genomic sequence information.
Project description:A custom multi-species microarray was used to study gene expression in wild hornyhead turbot (Pleuronichthys verticalis), collected from polluted and clean coastal waters in Southern California and in laboratory male zebrafish (Danio rerio) following exposure to estradiol and 4-nonylphenol. A multi-gene cross species microarray was fabricated as a diagnostic tool to screen the effects of environmental chemicals in fish, for which there is minimal genomic information. The microarray measurement of gene expression in zebrafish, which are phylogenetically distant from turbot, indicates that this multi-species microarray will be useful for measuring endocrine responses in Pleuronectiformes and other fish for which there is minimal genomic sequence information.