PUL ID

PUL0400

PubMed

25847866, Environ Microbiol. 2015 Oct;17(10):3857-68. doi: 10.1111/1462-2920.12862. Epub 2015 May 8.
30116038, ISME J. 2019 Jan;13(1):92-103. doi: 10.1038/s41396-018-0252-4. Epub 2018 Aug 16.

Characterization method

RT-qPCR,RNA-Seq

Genomic accession number

CABDWQ010000001.1

Nucelotide position range

1088947-1111260

Substrate

alginate

Loci

ALT831_00941-ALT831_00954

Species

Alteromonas macleodii/28108

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 2955 (+) CDS No
- 2965 - 3213 (+) CDS No
- 3346 - 4224 (+) CDS No
- 4277 - 6565 (+) CAZyme: PL6_1|PL6 Yes
- 6572 - 8776 (+) CAZyme: PL17|PL17_2 Yes
- 8795 - 9139 (+) STP: STP|AraC_binding Yes
- 9142 - 10437 (+) TC: gnl|TC-DB|Q07YH1|2.A.1.14.25 Yes
- 10505 - 11440 (+) STP: STP|PfkB Yes
- 11566 - 12183 (+) other Yes
- 12546 - 13286 (+) TF: DBD-Pfam|GntR,DBD-SUPERFAMILY|0039384 Yes
- 13413 - 14846 (-) CAZyme: CBM32|PL7_5 Yes
- 14920 - 18024 (-) TC: gnl|TC-DB|Q9A608|1.B.14.12.1 Yes
- 18501 - 21020 (+) CAZyme: PL6_3 Yes
- 21223 - 22314 (-) CAZyme: PL7_5 Yes

PUL ID

PUL0400

PubMed

25847866, Environ Microbiol. 2015 Oct;17(10):3857-68. doi: 10.1111/1462-2920.12862. Epub 2015 May 8.

Title

Different utilization of alginate and other algal polysaccharides by marine Alteromonas macleodii ecotypes.

Author

Neumann AM, Balmonte JP, Berger M, Giebel HA, Arnosti C, Voget S, Simon M, Brinkhoff T, Wietz M

Abstract

The marine bacterium Alteromonas macleodii is a copiotrophic r-strategist, but little is known about its potential to degrade polysaccharides. Here, we studied the degradation of alginate and other algal polysaccharides by A. macleodii strain 83-1 in comparison to other A. macleodii strains. Cell densities of strain 83-1 with alginate as sole carbon source were comparable to those with glucose, but the exponential phase was delayed. The genome of 83-1 was found to harbour an alginolytic system comprising five alginate lyases, whose expression was induced by alginate. The alginolytic system contains additional CAZymes, including two TonB-dependent receptors, and is part of a 24 kb genomic island unique to the A. macleodii 'surface clade' ecotype. In contrast, strains of the 'deep clade' ecotype contain only a single alginate lyase in a separate 7 kb island. This difference was reflected in an eightfold greater efficiency of surface clade strains to grow on alginate. Strain 83-1 furthermore hydrolysed laminarin, pullulan and xylan, and corresponding polysaccharide utilization loci were detected in the genome. Alteromonas macleodii alginate lyases were predominantly detected in Atlantic Ocean metagenomes. The demonstrated hydrolytic capacities are likely of ecological relevance and represent another level of adaptation among A. macleodii ecotypes.

PubMed

30116038, ISME J. 2019 Jan;13(1):92-103. doi: 10.1038/s41396-018-0252-4. Epub 2018 Aug 16.

Title

Biphasic cellular adaptations and ecological implications of Alteromonas macleodii degrading a mixture of algal polysaccharides.

Author

Koch H, Durwald A, Schweder T, Noriega-Ortega B, Vidal-Melgosa S, Hehemann JH, Dittmar T, Freese HM, Becher D, Simon M, Wietz M

Abstract

Algal polysaccharides are an important bacterial nutrient source and central component of marine food webs. However, cellular and ecological aspects concerning the bacterial degradation of polysaccharide mixtures, as presumably abundant in natural habitats, are poorly understood. Here, we contextualize marine polysaccharide mixtures and their bacterial utilization in several ways using the model bacterium Alteromonas macleodii 83-1, which can degrade multiple algal polysaccharides and contributes to polysaccharide degradation in the oceans. Transcriptomic, proteomic and exometabolomic profiling revealed cellular adaptations of A. macleodii 83-1 when degrading a mix of laminarin, alginate and pectin. Strain 83-1 exhibited substrate prioritization driven by catabolite repression, with initial laminarin utilization followed by simultaneous alginate/pectin utilization. This biphasic phenotype coincided with pronounced shifts in gene expression, protein abundance and metabolite secretion, mainly involving CAZymes/polysaccharide utilization loci but also other functional traits. Distinct temporal changes in exometabolome composition, including the alginate/pectin-specific secretion of pyrroloquinoline quinone, suggest that substrate-dependent adaptations influence chemical interactions within the community. The ecological relevance of cellular adaptations was underlined by molecular evidence that common marine macroalgae, in particular Saccharina and Fucus, release mixtures of alginate and pectin-like rhamnogalacturonan. Moreover, CAZyme microdiversity and the genomic predisposition towards polysaccharide mixtures among Alteromonas spp. suggest polysaccharide-related traits as an ecophysiological factor, potentially relating to distinct 'carbohydrate utilization types' with different ecological strategies. Considering the substantial primary productivity of algae on global scales, these insights contribute to the understanding of bacteria-algae interactions and the remineralization of chemically diverse polysaccharide pools, a key step in marine carbon cycling.