Phreatobacter sp. strain NMCR1094 was isolated from a freshwater stream. In this study, we report the complete genome sequence of strain NMCR1094, which contains 4,974,952 bp with 65.8% G+C content and 4,701 predicted coding sequences. In particular, the Phreatobacter sp. NMCR1094 genome contains a formate dehydrogenase region.

Rapid and cost-effective eDNA-based approaches are valuable for understanding biological communities and monitoring the biodiversity of inaccessible areas, such as large rivers and lakes. To determine temporal dynamics and precipitation effects on micro-eukaryotic assemblages, we monitored upstream (SJ) and downstream (MG) sites of the Nakdonggang River, monthly or bimonthly, from March 2019 to April 2021 using an eDNA metabarcoding technique. We observed 775 unique operational taxonomic units during the entire sampling period using the V4 region of the 18S rRNA gene as a marker. In the cluster analysis and non-metric multidimensional scaling analysis based on the relative abundance ratio of the micro-eukaryotic assemblages at the SJ and MG sites, respectively, both regions were classified by four seasons, with dominant taxa for each season being different. Whereas Chlorophyta was relatively abundant in the MG site during summer, diatoms were most abundant at the SJ site during winter. Further, metazoan taxa were relatively abundant at the MG site. Total detection of metazoa, protozoa, and microalgae taxa significantly increased with heavy rainfall. In addition, the indicator taxa representative for heavy rainfall and tolerance ranges of the amount of precipitation were predicted at both sites. As the frequency of drought and heavy rain is expected to increase owing to climate change, efforts to standardize the relation between precipitation and eDNA analysis are required.

A gamma radiation-resistant, Gram-stain-negative, rod-shaped bacterial strain, designated SJW1-2T, was isolated from freshwater samples collected from the Seomjin River, Republic of Korea. The 16S rRNA gene sequence analyses showed that strain SJW1-2T was most closely related to Deinococcus metalli 1PNM-19T (94.3 % sequence similarity) and formed a robust phylogenetic clade with other species of the genus Deinococcus . The optimum growth pH and temperature for the isolate were pH 7.0–7.5 and 25 °C, respectively. Strain SJW1-2T exhibited high resistance to gamma radiation. The predominant respiratory quinone was MK-8. The polar lipid profile consisted of different unidentified glycolipids, two unidentified lipids, two unidentified phospholipids and an unidentified phosphoglycolipid. The major peptidoglycan amino acids were alanine, d-glutamic acid, glycine and l-ornithine. The predominant fatty acids (>10 %) were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) (25.2 %) and C16 : 0 (21.2 %), and the DNA G+C content was 69.5 mol%. On the basis of phenotypic, genotypic and phylogenetic analyses, strain SJW1-2T (=KACC 19332T=NBRC 112908T) represents a novel species of the genus Deinococcus , for which the name Deinococcus koreensis sp. nov. is proposed.

A Gram-stain-negative, non-motile, non-pigmented, rod-shaped bacterium was isolated from a freshwater sample of Nakdong River in South Korea and designated as strain BK-30^T. An analysis of the 16S rRNA gene sequence of strain BK-30^T revealed its closest phylogenetic neighbors were members of the genus Macromonas. Specifically, the strain formed a robust clade with Macromonas bipunctata DSM 12705^T, sharing 98.4% similarity in their 16S rRNA gene sequences. The average nucleotide identity value between strain BK-30^T and M. bipunctata DSM 12705^T was 79.8%, and the genome-to-genome distance averaged 21.3%, indicating the representation of a novel genomic species. Strain BK-30^T exhibited optimum growth at 30 °C and pH 7.0, in the absence of NaCl. The major respiratory isoprenoid quinone identified was ubiquinone-8 (Q-8). The principal fatty acids detected were C_16:1 ω7c and/or C_16:1 ω6c (49.6%), C_16:0 (27.5%), and C_18:1 ω7c and/or C_18:1 ω6c (9.2%). The DNA G+C content of the strain was determined to be 67.3 mol%. Based on these data, we propose a novel species within the genus Macromonas, named Macromonas nakdongensis sp. nov., to accommodate the bacterial isolate. Strain BK-30^T is designated as the type strain (=KCTC 52161^T = JCM 31376^T = FBCC-B1). Additionally, we present the isolation and complete genome sequence of a lytic phage infecting strain BK-30^T, named BK-30P. This bacteriophage is the first reported to infect Macromonas, leading us to propose the name “Macromonasphage”.

Deinococcus koreensis SJW1-2 ^T was isolated from river water and was observed to be highly resistant to gamma radiation. In this study, we report a draft genome sequence which revealed that SJW1-2 ^T possesses genes involved in nucleotide excision repair.

This report details a draft genome sequence of Paucibacter aquatile CR182 ^T , isolated from river water, which contains 5,523,543 bp, has a G+C content of 66.3%, and harbors 4,544 protein-coding genes in 4 contigs. These genome data provide insights into the genetic basis of this strain’s antibacterial activity and adaptive mechanisms.