Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world’s oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.

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The Bacillus subtilis araR locus (mapped at about 294°on the genetic map) comprises two open reading frames with divergently arranged promoters, the regulatory gene, araR, encoding a repressor, and a partially cloned gene, termed araE by analogy to the Escherichia coli L-arabinose permease gene. Here, we report the cloning and sequencing of the entire araE gene encoding a 50.4-kDa polypeptide. The araE gene is monocistronic (as determined by Northern blot analysis), and its putative product is very similar to a number of prokaryotic proton-linked monosaccharide transporters (the group I family of membrane transport proteins). Insertional inactivation of the araE gene leads to a conditional Ara؊ phenotype dependent on the concentration of L-arabinose in the medium. Therefore, we assume that araE encodes a permease involved in L-arabinose transport into the cell. The araE promoter region contains ؊10 and ؊35 regions (as determined by primer extension analysis) very similar to those recognized by RNA polymerase containing the major vegetative-cell sigma factor A , and the ؊35 region of the transcription start point for araE is located 2 bp from the ؊35 region of the araR gene. Transcriptional studies demonstrated that the expression from the araE promoter is induced by L-arabinose, repressed by glucose, and negatively regulated by AraR. These observations are consistent with a model according to which in the absence of L-arabinose, AraR binds to a site(s) within the araE/araR promoter, preventing transcription from the araE promoter and simultaneously limiting the frequency of initiation from its own promoter; the addition of L-arabinose will allow transcription from the araE promoter and increase the frequency of initiation from the araR promoter.Bacillus subtilis can use L-arabinose as its sole carbon and energy source. The ability to utilize L-arabinose is dependent on three intracellular enzymes, L-arabinose isomerase, L-ribulokinase, and L-ribulose-5-phosphate-4-epimerase, which sequentially convert L-arabinose to L-ribulose, L-ribulose-5-phosphate, and D-xylulose-5-phosphate, respectively (8). D-Xylulose-5-phosphate is further catabolized through the pentose-phosphate pathway. This metabolic pathway is identical to the one found in Escherichia coli, and its enzymes were previously described as inducible by L-arabinose (8).The three metabolic genes, araA, araB, and araD, coding for L-arabinose isomerase, L-ribulokinase, and L-ribulose-5-phosphate-4-epimerase, respectively, are adjacent and constitute the first three open reading frames of a nine-cistron transcriptional unit with a total length of 11 kb (22,24). This operon, called araABDLMNPQ-abfA, is located at about 256°on the B. subtilis genetic map (18) and includes six other genes named araL, araM, araN, araP, araQ, and abfA. Analysis of the sequence of the ara operon showed that the putative products of araN, araP, and araQ are homologous to bacterial components of binding-protein-dependent transport systems and that the abfA gene most probably codes for...

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