Project description:Sulfate-reducing bacteria (SRB) play a pivotal role in the global carbon- and sulfur cycles, especially in the marine environment. Here, continental margins, coastal ranges, and shelf sediments stand out by their high input of organic matter, and more than 50% of their mineralization is achieved in the upper sediment layers, coupled to sulfate reduction. This turnover is mainly achieved by members of the family of Desulfobacteraceae of completely oxidizing SRB. Desulfosarcina variabilis 3be13 is a member of this family.
Project description:For the filamentous cyanobacterium Anabaena variabilis to grow without combined nitrogen, certain cells differentiate into heterocysts that fix N2, while vegetative cells perform photosynthesis. Much remains unknown on how heterocysts differ from vegetative cells in terms of carbon and energy metabolisms. Microarrays were used to investigate gene transcription patterns in vegetative cells, heterocysts, and filaments of N2-fixing phototrophic, mixotrophic, and heterotrophic cultures. Hybridizations used NimbleGen expression array chips (Product no. A4385-00-01, platform accession no GPL15883) designed against the 5,657 ORFs encoded in the A. variabilis genome (GenBank accession no. CP000117). Each ORF was represented by seventeen 60-mer oligonucleotides. Each oligonucleotide was present in four internal replicates. The twenty-seven microarray data files were normalized against each other. Expression array data were analyzed using ArrayStar 3.0 (DNASTAR, Madison, WI).