Nterest for brown algae, and in specific E. siliculosus, the ability in the latter alga to produce these vitamins was investigated. Corresponding genes were searched for in the algal genome (Cock et al., 2010) too as in a recent metabolic network reconstruction (http:ectogem.irisa.fr, Prigent et al., pers. com.) and in comparison to our results for “Ca. P. ectocarpi.” This analysis indicated that all of these vitamins might be produced by E. siliculosus independently with the bacterium. Thiamine is definitely an crucial co-factor for catabolism of amino acids and sugars, and several proteins within the Ectocarpus genome had been found to contain a domain on the superfamily thiamin diphosphatebinding fold (THDP-binding), indicating that these enzymes depend on thiamin as a cofactor. Nevertheless, E. siliculosus also features a bacteria-like thiamine pyrophosphatase synthesis pathway (PWY-6894), and no genes involved in thiamine transport have been identified within the algal genome. Flavin is often a precursor for the synthesis of flavine adenine dinucleotide (FAD) and flavine mononucleotide (FMN), and the algal genome consists of various flavoproteins and proteins with FAD binding domains. Even so, quite a few enzymes comparable to these involved in bacterialplant, fungal, and mammalian pathways for flavin synthesis had been identified in E. siliculosus (RIBOSYN2-PWY). Pyridoxine is degraded by the pyridoxal salvage pathway to create pyridoxal phosphate, a co-factor essential for a lot of reactions associated to amino acid metabolism (transamination, deamination, and decarboxylation). In E. siliculosus the salvage pathway for the synthesis of this compound has been identified (PLPSAL-PWY). Biotin is usually a vitamin involved in sugar and fatty acid metabolism, and many biotin-dependent carboxylases, i.e., enzymes featuring a biotin-binding web-site (IPR001882), have already been annotated inside the E. siliculosus genome. Again the algal genome encodes two enzymes most likely to catalyze the three enzymatic reactions essential to synthesize biotin from A3334 In Vivo 8-amino-7-oxononanoate (Esi0392_0016, a bifunctional dethiobiotin synthetase7,8-diamino-pelargonic acid aminotransferase; Esi0019_0088, a biotin synthase) (PWY0-1507). Ascorbate is definitely an essential vitamin in plants where it serves as antioxidant in chloroplasts and as a cofactor for some hydroxylase enzymes (Smirnoff, 1996), and we found an L-galactose (plant-type) pathway for ascorbate synthesis in E. siliculosus (PWY-882). Lastly, the E. siliculosus genome encodes various methyltransferases potentially involved inside the final step of vitamin K2 synthesis, in distinct for menaquinol-6, -7 and -8 (Esi0009_0155, Esi0182_0017, and Esi0626_0001).In contrast to the aforementioned vitamins, vitamin B12 cannot be produced by either “Ca. P. ectocarpi” or E. siliculosus. The “Ca. P. ectocarpi” genome encodes only some genes equivalent to these involved in aerobic or anaerobic cobalamin synthesis, as well as the aforementioned presence of a vitamin-B12 importer indicates that “Ca. P. ectocarpi” may possibly itself be vitamin-B12 auxotroph. Within the exact same vein, it has been lately described that E. siliculosus will not be in a position to produce vitamin B12, but that it could develop with no external source of this compound. Having said that, the E. siliculosus genome consists of numerous vitamin MK-7655 Bacterial B12-dependent enzymes (Helliwell et al., 2011), suggesting that vitamin B12 may well nonetheless be helpful for the alga. Ultimately, the absence of a gene coding for any 2-dehydropantoate 2-reductase (EC 1.1.1.169) in each “Ca. P. ectocarpi”.