- Volume 75, Issue 2, 2025

Two novel Gram-stain-negative, aerobic, heterotrophic, non-motile bacterial strains, designated as AS3R-12T and PS1R-30T, were isolated from freshwater in South Korea. To determine their taxonomic positions, the strains were thoroughly characterized. Genomic analyses, based on 16S rRNA gene and draft genome sequence data, revealed that the two novel isolates, AS3R-12T and PS1R-30T, belonged to the genus Novosphingobium. AS3R-12T showed the highest 16S rRNA gene similarity (97.7%) with Novosphingobium flavum UCT-28T. In addition, PS1R-30T showed 97.9% 16S rRNA gene similarity with Novosphingobium lentum NBRC 107847T. The draft genome of strains AS3R-12T and PS1R-30T consisted of 4 149 275 and 4 969 838 bps, with DNA G+C content of 63.1 and 66.1 mol%, respectively. The average nucleotide identity between two strains and other related species was below 76.2%, and the digital DNA–DNA hybridization values with closely related species were below 20.8%, both lower than the species delineation threshold. Strains AS3R-12T and PS1R-30T contained the ubiquinone Q-10 as the major quinone and displayed a polyamine pattern with spermidine as the predominant polyamine. Additionally, their major fatty acids were characterized by C16:1  ω7c/C16:1  ω6c (summed feature 3) and C18:1  ω7c/C18:1  ω6c (summed feature 8). The major polar lipids of AS3R-12T and PS1R-30T were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), sphingoglycolipid (SGL) and phosphatidylcholine (PC). Moreover, physiological and biochemical results allowed the phenotypic and genotypic differentiation of strains AS3R-12T and PS1R-30T from their closest and other species of the genus Novosphingobium with validly published names. Therefore, AS3R-12T and PS1R-30T represented novel species of the genus Novosphingobium, for which the names Novosphingobium aquae sp. nov. (type strain AS3R-12T=KACC 23096T=LMG 32950T) and Novosphingobium anseongense sp. nov. (type strain PS1R-30T=KACC 23097T=LMG 32951T) are proposed.

Hanseniaspora, a genus of yeasts in which many species reproduce sexually, has attracted the attention of researchers because of its prevalence in diverse ecological niches. Building on our extensive collection efforts since 2020, three previously unknown yeast strains from wild Drosophila species trapped in ripe bananas in Okinawa, Japan, were isolated. Using a multifaceted approach, including physiological assessments and sequence analysis of the D1/D2 domain of the 26S LSU rRNA gene and the internal transcribed spacer (ITS) region, it was revealed that these strains are novel members of the genus Hanseniaspora. The three strains, JCM 36741T, JCM 36742 and JCM 36748, had identical sequences in their respective D1/D2 and ITS regions, justifying their classification as a single species. Moreover, the new species exhibited a remarkable degree of sequence divergence from its closest relatives, differing by 7 nucleotide substitutions (1.28%) in the D1/D2 domain, 29 nucleotide substitutions and 4 gaps (4.08%) in the ITS regions. These substantial sequence differences highlight the distinctiveness of this novel species in the genus Hanseniaspora. Further analysis revealed physiological characteristics that distinguished the new species from its closest relative, Hanseniaspora hatyaiensis (nom. inval.). These findings culminated in the proposed name Hanseniaspora drosophilae sp. nov., which recognizes the unique ecological niche within the Drosophila microbiota. By uncovering this novel species, this study not only adds to the growing body of knowledge on yeast diversity but also sheds light on the intricate ecological relationships that shape microbial communities. The implications of this discovery extend beyond taxonomic boundaries, inviting further exploration of the evolutionary dynamics and ecological significance of yeast–fly interactions. We propose accommodating H. drosophilae sp. nov. in the genus Hanseniaspora with JCM 36741T as the holotype. The MycoBank accession number is MB 853822.

Opinion 131 addresses a Request for an Opinion asking the Judicial Commission to conserve the genus name Proteus Hauser 1885 (Approved Lists 1980) over its earlier homonym, the protozoan genus name Proteus Müller 1786. The Judicial Commission agrees that the later homonym is illegitimate and that the replacement of the prokaryotic name Proteus would be undesirable. It is also concluded that Proteus Müller 1786 is an objectively invalid name under the International Code of Zoological Nomenclature. Judicial Opinions 9, 12 and 130 serve as precedents for the conservation of Proteus Hauser 1885 (Approved Lists 1980) over Proteus Müller 1786. This action is taken here and makes the prokaryotic name Proteus legitimate.