Algoriphagus lacus sp. nov., isolated from a freshwater lake.

A Gram-stain-negative, non-motile, rod-shaped, oxidase-positive, red-pigmented bacterium, strain N3T, was isolated from Fuxian lake, a freshwater lake in Yunnan Province, PR China. Strain N3T was facultatively anaerobic, heterotrophic and negative for catalase. Optimal growth occurred at 30 °C (range 4-45 °C), pH 7.0-8.0 (range 6.5-9.5) and in the presence of 0-3 % (w/v) NaCl (range 0-3 %). The results of phylogenetic analysis based on 16S rRNA gene sequencing revealed that strain N3T was close to the type strains of Algoriphagus aquaeductus, Algoriphagus shivajiensis and Algoriphagus alkaliphilus with sequence similarities of 97.4, 97.3 and 97.2 % respectively. The G+C content of the genomic DNA was 43.9 mol%. The quinone system contained menaquinone MK-7 as the sole component. The major fatty acids were iso-C15 : 0, summed feature 9 (10-methyl C16 : 0 and/or iso-C17 : 1 ω9c), summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω 7c) and iso-C16 : 0. Major polar lipids were phosphatidylcholine, phosphatidylethanolamine, an unidentified glycolipid, one unidentified phospholipid, two unidentified aminolipids and four unidentified lipids. On the basis of physiological, chemotaxonomic and molecular properties as well as phylogenetic distinctiveness, strain N3T should be placed into the genus Algoriphagus as a novel species, for which the name Algoriphagus lacus sp. nov. is proposed. The type strain is N3T (=KCTC 62622T=MCCC 1H00308T).

Aquiflexum aquatile sp. nov., isolated from lake water.

A Gram-stain-negative, facultative anaerobic, red-coloured, rod-shaped, non-flagellated, non-motile and non-gliding bacterium, designated strain Z0201T, was isolated from lake water in Yunnan, China (26° 16' N, 99° 94' E). Cells of strain Z0201T were 0.2-0.4 µm wide and 1.4-2.5 µm long, catalase-positive and oxidase-negative. Strain Z0201T was found to grow at 4-37 °C (optimum, 30 °C) and pH 6.5-8.5 (pH 7.5) in the presence of 0-2.0 % (w/v) NaCl (0-0.5 %). The sole respiratory quinone of strain Z0201T was MK-7 and the DNA G+C content was 41.2 mol%. The major fatty acid was iso-C15 : 0 (49.4 %). The polar lipid profile of strain Z0201T consisted of aminophospholipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, two unidentified phospholipids and five unidentified lipids. Based on the 16S rRNA gene sequence analysis, strain Z0201T was a member of the genus Aquiflexum, appearing to be closely related to Aquiflexum balticum (95.4 %). On the basis of phenotypic distinctiveness and phylogenetic divergence, strain Z0201T is considered to represent a novel species of the genus Aquiflexum, for which the name Aquiflexumaquatile sp. nov. is proposed. The type strain is Z0201T (=KCTC 62450T=MCCC 1H00328T).

Jannaschia formosa sp. nov., isolated from marine saltern sediment.

A novel blush-red-pigmented, Gram-stain-negative, gliding, aerobic and rod- or oval-shaped bacterium, designated strain 12N15T, was isolated from sediment sampled at a marine saltern located in Wendeng, China (36° 59' 56.49″ N, 122° 1' 38.84″ E). Growth was observed at 10-40 °C (optimum, 28 °C), in 1.0-12.0 % NaCl (2.0-5.0 %, w/v) and at pH 6.0-9.5 (pH 7.0). The respiratory quinones were determined to be Q-10 and major fatty acids were C18 : 1ω7c and C18 : 0. The polar lipids profile of strain 12N15T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminolipid, phosphatidylcholine, one lipid and three phospholipids. The genomic DNA G+C content was 69.6 mol%. Phylogenetic analyses based on the 16S rRNA gene showed that the strain 12N15T was affiliated within the genus Jannaschia, and was most closely related to Jannaschia seohaensis KCTC 22172T. The average amino acid identity and percentage of conserved protein values between strain 12N15T and the type strain of the type species, Jannaschia helgolandensis DSM 14858T, were 70.2 % and 64.1 %, respectively. The average nucleotide identity value between strain 12N15T and J.annaschia seohaensis KCTC 22172T was 81.9 %. The phenotypic, phylogenetic and genomic analyses supported the hypothesis that strain 12N15T represents a novel species of the genus Jannaschia, for which the name Jannaschia formosa sp. nov. is proposed. The type strain is 12N15T (=MCCC 1H00325T=KCTC 62582T).

Aliidiomarina celeris sp. nov., isolated from coastal sediment.

A Gram-stain-negative, heterotrophic, facultative anaerobic, gliding and motile bacterium, approximately 0.6-0.9 µm wide and 1.5-2.6 µm long, designated F3105T, was isolated from a marine sediment sample collected along the coast of Rongcheng, China . The growth of strain F3105T occurred on media with 1.0-8.0 % (w/v) NaCl (optimum, 2.0-3.0 %) and a pH of 6.5-9.5 (optimum, pH 7.5) at 4-45 °C (optimum, 37 °C). The phylogenetic analysis of the 16S rRNA gene and chemotaxonomic data revealed that the isolate belonged to the genus Aliidiomarina, and is closely related to Aliidiomarina shirensis (95.9 % sequence similarity). The sole isoprenoid quinone was Q-8. The major cellular fatty acids of the isolate were iso-C15 : 0, iso-C17 : 1ω9c and iso-C17 : 0, and its polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, aminolipid, two unidentified lipids and two unidentified aminophospholipids. The DNA G+C content of strain F3105T was 49.5 mol%. On the basis of phenotypic distinctiveness and phylogenetic divergence, strain F3105T is considered to represent a novel species of the genus Aliidiomarina, for which the name Aliidiomarinaceleris sp. nov. is proposed. The type strain is F3105T (=MCCC 1H00223T=KCTC 52891T).

Halioglobus lutimaris sp. nov., isolated from coastal sediment.

A novel Gram-stain-negative, strictly aerobic, non-flagellated and rod-shaped bacterium, designated HF004T, was isolated from a marine sediment sample collected from the coast of Weihai, China. The strain grew optimally at 28 °C, pH 7.5-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Based on the 16S rRNA gene sequence analysis, strain HF004T was a member of the genus Halioglobus, appearing to be closely related to Halioglobus pacificus (96.1 %) and Halioglobus japonicus (95.6 %). The major fatty acids were summed feature 3 (i.e. C16 : 1ω7c and/or iso-C15 : 0 2-OH), C17 : 1ω8c and C18 : 1ω7c. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The predominant respiratory quinone was Q-8. The DNA G+C content was 57.2 mol%. Cells of strain HF004T were rod-shaped and formed circular, mucous and beige-pigmented colonies on marine agar after incubation for 72 h at 28 °C. On the basis of phenotypic, genotypic and phylogenetic evidence, strain HF004T is presented as a novel species, for which the name Halioglobus lutimaris sp. nov. is proposed. The type strain is HF004T (=KCTC 42395T=MCCC 1H00127T).

Algoriphagus formosus sp. nov., isolated from coastal sediment.

A Gram-stain negative, facultative anaerobic, non-motile, strongly orange-pigmented and rod-shaped bacterium, designated XAY3209T, was isolated from a marine sediment sample collected from the coast of Weihai, China. Strain XAY3209T was found to grow optimally at 30 °C, at pH 7.0 and in the presence of 2.0% (w/v) NaCl. Its genomic DNA G+C content was 41.9 mol%. On the basis of 16S rRNA gene sequence similarity, the novel isolate belongs to the family Cyclobacteriaceae and is related to the genus Algoriphagus. It shares 98.1% 16S rRNA sequence identity with Algoriphagus marincola, its close phylogenetic relative, but did not show similarities more than 97% with other members of the genus Algoriphagus with validly published names. It contained menaquinone-7 (MK-7) as the sole respiratory quinone, iso-C15:0, iso-C17:1 ω9c and Summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH) as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified phospholipid and five unidentified lipids. Results of physiological experiments, biochemical tests and genome average nucleotide identity value (with A. marincola MCCC 1F01203T) indicate that strain XAY3209T is genetically and phenotypically distinct from the species of the genus Algoriphagus with validly published names. Strain XAY3209T therefore represents a novel species, for which the name Algoriphagus formosus sp. nov. is proposed. The type strain is XAY3209T (= KCTC 52842T = MCCC 1H00189T).

Spatial Chromosome Organization and Adaptation of Escherichia coli under Heat Stress.

The spatial organization of bacterial chromosomes is crucial for cellular functions. It remains unclear how bacterial chromosomes adapt to high-temperature stress. This study delves into the 3D genome architecture and transcriptomic responses of Escherichia coli under heat-stress conditions to unravel the intricate interplay between the chromosome structure and environmental cues. By examining the role of macrodomains, chromosome interaction domains (CIDs), and nucleoid-associated proteins (NAPs), this work unveils the dynamic changes in chromosome conformation and gene expression patterns induced by high-temperature stress. It was observed that, under heat stress, the short-range interaction frequency of the chromosomes decreased, while the long-range interaction frequency of the Ter macrodomain increased. Furthermore, two metrics, namely, Global Compactness (GC) and Local Compactness (LC), were devised to measure and compare the compactness of the chromosomes based on their 3D structure models. The findings in this work shed light on the molecular mechanisms underlying thermal adaptation and chromosomal organization in bacterial cells, offering valuable insights into the complex inter-relationships between environmental stimuli and genomic responses.