Project description:Laminarin is a cytosolic storage polysaccharide of phytoplankton and macroalgae and accounts for over 10% of the world´s annually fixed carbon dioxide. Algal disruption, e.g., by viral lysis releases laminarin. The soluble sugar is rapidly utilized by free-living planktonic bacteria, in which sugar transporters and the degrading enzymes are frequently encoded in polysaccharide utilization loci. The annotation of flavobacterial genomes failed to identify canonical laminarin utilization loci in several particle-associated bacteria, in particular in strains of Maribacter. In this study, we report in vivo utilization of laminarin by Maribacter forsetii accompanied by additional cell growth and proliferation. Laminarin utilization coincided with the induction of an extracellular endo-laminarinase, SusCD outer membrane oligosaccharide transporters and a periplasmic glycosyl hydrolase family 3 protein. ABC transporter and sugar kinases were expressed. Endo-laminarinase activity was also observed in Maribacter sp. MAR_2009_72, Maribacter sp. Hel_I_7 and Maribacter dokdonensis MAR_2009_60. Maribacter dokdonensis MAR_2009_71 lacked the large endo-laminarinase gene in the genome and had no endo-laminarinase activity. In all genomes, genes of induced proteins were scattered across the genome rather than clustered in a laminarin utilization locus. These observations revealed that the Maribacter strains investigated in this study participate in laminarin utilization, but in contrast to many free-living bacteria, there is no co localisation of genes encoding the enzymatic machinery for laminarin utilization.
Project description:Laminarin is a cytosolic storage polysaccharide of phytoplankton and macroalgae and accounts for over 10% of the world´s annually fixed carbon dioxide. Algal disruption, e.g., by viral lysis releases laminarin. The soluble sugar is rapidly utilized by free-living planktonic bacteria, in which sugar transporters and the degrading enzymes are frequently encoded in polysaccharide utilization loci. The annotation of flavobacterial genomes failed to identify canonical laminarin utilization loci in several particle-associated bacteria, in particular in strains of Maribacter. In this study, we report in vivo utilization of laminarin by Maribacter forsetii accompanied by additional cell growth and proliferation. Laminarin utilization coincided with the induction of an extracellular endo-laminarinase, SusCD outer membrane oligosaccharide transporters and a periplasmic glycosyl hydrolase family 3 protein. ABC transporter and sugar kinases were expressed. Endo-laminarinase activity was also observed in Maribacter sp. MAR_2009_72, Maribacter sp. Hel_I_7 and Maribacter dokdonensis MAR_2009_60. Maribacter dokdonensis MAR_2009_71 lacked the large endo-laminarinase gene in the genome and had no endo-laminarinase activity. In all genomes, genes of induced proteins were scattered across the genome rather than clustered in a laminarin utilization locus. These observations revealed that the Maribacter strains investigated in this study participate in laminarin utilization, but in contrast to many free-living bacteria, there is no co localisation of genes encoding the enzymatic machinery for laminarin utilization.
Project description:Laminarin is a cytosolic storage polysaccharide of phytoplankton and macroalgae and accounts for over 10% of the world´s annually fixed carbon dioxide. Algal disruption, e.g., by viral lysis releases laminarin. The soluble sugar is rapidly utilized by free-living planktonic bacteria, in which sugar transporters and the degrading enzymes are frequently encoded in polysaccharide utilization loci. The annotation of flavobacterial genomes failed to identify canonical laminarin utilization loci in several particle-associated bacteria, in particular in strains of Maribacter. In this study, we report in vivo utilization of laminarin by Maribacter forsetii accompanied by additional cell growth and proliferation. Laminarin utilization coincided with the induction of an extracellular endo-laminarinase, SusCD outer membrane oligosaccharide transporters and a periplasmic glycosyl hydrolase family 3 protein. ABC transporter and sugar kinases were expressed. Endo-laminarinase activity was also observed in Maribacter sp. MAR_2009_72, Maribacter sp. Hel_I_7 and Maribacter dokdonensis MAR_2009_60. Maribacter dokdonensis MAR_2009_71 lacked the large endo-laminarinase gene in the genome and had no endo-laminarinase activity. In all genomes, genes of induced proteins were scattered across the genome rather than clustered in a laminarin utilization locus. These observations revealed that the Maribacter strains investigated in this study participate in laminarin utilization, but in contrast to many free-living bacteria, there is no co localisation of genes encoding the enzymatic machinery for laminarin utilization.
Project description:Arabinose and galactose are major components of both particulate and dissolved organic matter. They often constitute polysaccharides such as arabinogalactan. Field studies have demonstrated a turnover of arabinogalactan, but enzymes and organisms involved have not been explored. In this study, the degradation of arabinogalactan by the marine flavobacterium Maribacter sp. MAR_2009_72 was investigated with growth experiments and proteomic analyses. Growth of Maribacter sp. MAR_2009_72 on arabinogalactan displayed its ability to utilize arabinogalactan. Proteomic analysis of cells grown on arabinogalactan, arabinose, galactose or glucose revealed expression of specific proteins in presence of arabinogalactan, mainly glycoside hydrolases. Candidates for extracellular glycan hydrolysis are five alpha-L-arabinofuranosidases affiliating with glycosyl hydrolase (GH) families 43 and 51, four unsaturated rhamnogalacturonyl hydrolases (GH105) and a protein with a glycosyl hydrolase family like domain. We detected expression of three induced TonB-dependent SusCD transporter systems, one SusC and nine glycosyl hydrolases with a predicted periplasmatic location. These are affiliated with the families GH3, GH10, GH29, GH31, GH67, GH78 and GH115. The genes are located within three canonical polysaccharide utilization loci (PUL), but also outside of the defined loci. PULs can be classified as specific for arabinogalactan, galactose-containing glycans and for arabinose-containing glycans. The breadth of enzymatic functions expressed in Maribacter sp. MAR_2009_72 as response to arabinogalactan from terrestrial plant larch suggests that Flavobacteriia are main catalysts of the rapid turnover of arabinogalactans in the marine environment.
Project description:Laminarin is a cytosolic storage polysaccharide of phytoplankton and macroalgae and accounts for over 10% of the world´s annually fixed carbon dioxide. Algal disruption, e.g., by viral lysis releases laminarin. The soluble sugar is rapidly utilized by free-living planktonic bacteria, in which sugar transporters and the degrading enzymes are frequently encoded in polysaccharide utilization loci. The annotation of flavobacterial genomes failed to identify canonical laminarin utilization loci in several particle-associated bacteria, in particular in strains of Maribacter. In this study, we report in vivo utilization of laminarin by Maribacter forsetii accompanied by additional cell growth and proliferation. Laminarin utilization coincided with the induction of an extracellular endo-laminarinase, SusCD outer membrane oligosaccharide transporters and a periplasmic glycosyl hydrolase family 3 protein. ABC transporter and sugar kinases were expressed. Endo-laminarinase activity was also observed in Maribacter sp. MAR_2009_72, Maribacter sp. Hel_I_7 and Maribacter dokdonensis MAR_2009_60. Maribacter dokdonensis MAR_2009_71 lacked the large endo-laminarinase gene in the genome and had no endo-laminarinase activity. In all genomes, genes of induced proteins were scattered across the genome rather than clustered in a laminarin utilization locus. These observations revealed that the Maribacter strains investigated in this study participate in laminarin utilization, but in contrast to many free-living bacteria, there is no co localisation of genes encoding the enzymatic machinery for laminarin utilization.