Abstract
Isolation of the strains
Strain Q31bT was sampled on the 5th of June 2013 from jellyfish (Aurelia aurita) on the north-western shore of Heligoland island in the North Sea (54.188 N, 7.875 E). Strain Poly41T was isolated from polystyrene particles embedded in an incubator in the water of the Baltic Sea for 14 days in 2 m depth at Heiligendamm Pier, Germany (54.146 N, 11.843 E). Collection date was the 8th of October 2015, when the incubator was removed from the water. Strain Pla52oT was isolated as described for strain Poly41T, but pieces of wood were embedded in the incubator instead of polystyrene particles. The incubation took place at exactly the same location (54.146 N, 11.843 E), but 1 year earlier (sampling date: 4. September 2014). Strains were isolated from the artificial (polystyrene) or natural (wood, jellyfish) sampling material as described in detail before (Wiegand et al. 2019). Initial amplification and sequencing of the 16S rRNA gene was performed as previously described (Rast et al. 2017). For subsequent cultivations M1 medium with HEPES as buffering agent and additionally supplemented with N-acetyl glucosamine (NAG) and artificial seawater (ASW) was used (designated M1H NAG ASW). Medium preparation was described previously (Kallscheuer et al. 2019a).
Light microscopy and scanning electron microscopy
Phase contrast microscopy and field emission scanning electron microscopy were performed according to protocols published earlier (Kallscheuer et al. 2019a).
Genome analysis
Genome information of the three isolated strains is available from GenBank under accession numbers SJPV00000000 (Poly41T), SJPY00000000 (Q31bT) and SJPT00000000 (Pla52oT). The corresponding 16S rRNA gene sequences are also available from GenBank under accession numbers MK554551 (Poly41T), MK554555 (Q31bT) and MK554549 (Pla52oT). Completeness and contamination of the genomes was determined using CheckM v1.0.131 (Parks et al. 2015). The primary metabolism was analysed by examining locally computed InterProScan (Mitchell et al. 2019) results cross-referenced with information from the UniProt database and BLASTp results of ‘typical’ protein sequences. The carbohydrate active enzymes were determined by employing dbCAN2 (Zhang et al. 2018), which automatically mines the CAZy database (Lombard et al. 2014).
Physiological analysis
For determination of the pH optimum 100 mM HEPES was used for cultivations at pH 7.0, 7.5 and 8.0. For cultivations at pH 5.0 and 6.0 HEPES was replaced by 100 mM 2-(N-morpholino)ethanesulfonic acid (MES), whereas 100 mM N-cyclohexyl-2-aminoethane-sulfonic acid (CHES) served as a buffering agent at pH 9.0 and 10.0. Cultivations for determination of the pH optimum were performed at 28 °C in triplicates. For determination of the temperature optimum the strains were cultivated at temperatures ranging from 10 to 40 °C in standard M1H NAG ASW medium at pH 7.5 in triplicates.
