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Pseudomonas species are known for their diverse metabolic abilities and broad ecological distribution. They are fundamental components of bacterial communities and perform essential ecological functions in the environment. A psychrotrophic Pseudomonas sp. IT1137 was isolated from intertidal sediment in the coastal region of the Fildes Peninsula, King George Island, Antarctica. The strain contained a circular chromosome of 5,346,697 bp with a G + C content of 61.66 mol% and one plasmid of 4481 bp with a G + C content of 64.61 mol%. A total of 4848 protein-coding genes, 65 tRNA genes and 15 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1137 not only is a potentially novel species of the genus Pseudomonas but also harbors functional genes related to nitrogen, sulfur and phosphorus cycling. In addition, genes involved in alkane degradation, ectoine synthesis and cyclic lipopeptide (CLP) production were detected in the bacterial genome. The results indicate the potential of the strain Pseudomonas sp. IT1137 for biotechnological applications such as bioremediation and secondary metabolite production and are helpful for understanding bacterial adaptability and ecological function in cold coastal environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Two Gram-stain-negative, aerobic, rod-shaped, non-endospore-forming and motile bacterial strains, designated IT1137 T and S025 T , were isolated from an intertidal sediment sample collected from the Fildes Peninsula (King George Island, Maritime Antarctica) and a soil sample under red snow in the Ny-Ålesund region (Svalbard, High Arctic), respectively. The 16S rRNA gene sequence similarity values grouped them in the genus Pseudomonas . The two strains were characterized phenotypically using API 20E, API 20NE, API ZYM and Biolog GENIII tests and chemotaxonomically by their fatty acid contents, polar lipids and respiratory quinones. Multilocus sequence analysis (concatenated 16S rRNA, gyrB , rpoB and rpoD sequences), together with genome comparisons by average nucleotide identity and digital DNA-DNA hybridization, were performed. The results showed that the similarity values of the two isolates with the type strains of related Pseudomonas species were below the recognized thresholds for species definition. Based on polyphasic taxonomy analysis, it can be concluded that strains IT1137 T and S025 T represent two novel species of the genus Pseudomonas , for which the names Pseudomonas paeninsulae sp. nov. (type strain IT1137 T =PMCC 100533 T =CCTCC AB 2023226 T =JCM 36637 T ) and Pseudomonas svalbardensis sp. nov. (type strain S025 T =PMCC 200367 T = CCTCC AB 2023225 T =JCM 36638 T ) are proposed.

Bacteria of the genus Oceanisphaera in the class Gammaproteobacteria are widely distributed in marine environments. Oceanisphaera sp. IT1-181 was isolated from intertidal sediment in the coastal region of the Chinese Great Wall Station on the Fildes Peninsula, King George Island, Antarctica. Here, we sequenced the complete genome of strain IT1-181, which contained a single chromosome of 3,572,184 bp (G + C content of 49.89 mol%) with five plasmids. A total of 3229 protein-coding genes, 88 tRNA genes, and 25 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1-181 was not only a potentially novel species of the genus Oceanisphaera, but also harbored genes involved in biosynthesizing ectoine as well as poly-β-hydroxybutyric acid (PHB). In addition, genes of a complete type I-E CRISPR-Cas system were found in the bacterium. The results indicate the potential of strain Oceanisphaera sp. IT1-181 in biotechnology and are helpful for us understanding its ecological roles in the changing Antarctic intertidal zone environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Dimethylsulfoniopropionate (DMSP) is an organic sulfur compound that occurs in large amounts in oceans around the world, and it plays an important role in the global sulfur cycle. DMSP released into seawater can be rapidly catabolized by bacteria via two pathways, namely, demethylation or cleavage pathway. Members of the Roseobacter clade frequently possess enzymes involved in the DMSP demethylation or cleavage pathway. We tried to measure the diversity of genes encoding DMSP demethylase (dmdA) and DMSP lyases (dddD, dddL, and dddP) in bacteria in the surface seawater of Ardley Cove and Great Wall Cove in Antarctic Maxwell Bay using DMSP degradation gene clone library analysis. Although we did not detect sequences related to the dddD or dddL gene, both bacterial dmdA and dddP genes found in the two coves were completely confined to the Roseobacter clade, which indicated that this clade plays a significant role in DMSP catabolism in the coastal seawaters of Maxwell Bay. In addition, compared with bacterial DMSP degradation genes in Arctic coastal seawater, our results suggest that both bipolar and endemic bacterial DMSP degradation genes exist in polar marine environments. The findings of this study improve our knowledge of the distribution of DMSP degradation genes in polar marine ecosystems.

A yellow-coloured, rod-shaped, Gram-reaction- and Gram-staining-negative, non-motile and aerobic bacterium, designated strain ZS1-8(T), was isolated from a sample of sandy intertidal sediment collected from the Antarctic coast. Flexirubin-type pigments were absent. In phylogenetic analyses based on 16S rRNA gene sequences, strain ZS1-8(T) formed a distinct phyletic line and the results indicated that the novel strain should be placed in a new genus within the family Flavobacteriaceae. In pairwise comparisons between strain ZS1-8(T) and recognized species, the levels of 16S rRNA gene sequence similarity were all <93.3 %. The strain required Ca(2+) and K(+) ions as well as NaCl for growth. Optimal growth was observed at pH 7.5-8.0, 17-19 °C and with 2-3 % (w/v) NaCl. The major fatty acids were iso-C(15 : 1) G, iso-C(15 : 0), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c), an unknown acid with an equivalent chain-length of 13.565 and iso-C(17 : 0) 3-OH. The major respiratory quinone was MK-6. The predominant polar lipid was phosphatidylethanolamine. The genomic DNA G+C content was 43.9 mol%. Based on the phylogenetic, phenotypic and chemotaxonomic data, strain ZS1-8(T) represents a novel species in a new genus in the family Flavobacteriaceae for which the name Pricia antarctica gen. nov., sp. nov. is proposed. The type strain of the type species is ZS1-8(T) (= JCM 17291(T) = DSM 23421(T)).

Strain ZS314(T) was isolated from a sandy intertidal sediment sample collected from the coastal area off the Chinese Antarctic Zhongshan Station, east Antarctica (6 9° 22' 13″ S 76 ° 21' 41″ E). The cells were Gram-positive, motile, short rods. The temperature range for growth was 0-26 °C and the pH for growth ranged from 5 to 10, with optimum growth occurring within the temperature range 18-23 °C and pH range 6.0-8.0. Growth occurred in the presence of 0-6 % (w/v) NaCl, with optimum growth occurring in the presence of 2-4 % (w/v) NaCl. Strain ZS314(T) had MK-10 as the major menaquinone and anteiso-C(15 : 0), iso-C(16 : 0) and anteiso-C(17 : 0) as major fatty acids. The cell-wall peptidoglycan type was B2β with ornithine as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The genomic DNA G+C content was approximately 67 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain ZS314(T) represents a new lineage in the family Microbacteriaceae. On the basis of the phylogenetic analyses and phenotypic characteristics, a new genus, namely Marisediminicola gen. nov., is proposed, harbouring the novel species Marisediminicola antarctica sp. nov. with the type strain ZS314(T) (=DSM 22350(T) =CCTCC AB 209077(T)).