Nylund, Are


Publications (7)

Phylogenetic analyses of Candidatus Branchiomonas cysticola refine the taxonomic classification of Betaproteobacteria associated with epitheliocystis in fish

Citation
Bysveen Mjølnerød et al. (2023). Archives of Microbiology 205 (6)
Names (3)
“Branchiomonaceae” Ca. Branchiomonas Ca. Branchiomonas cystocola
Subjects
Biochemistry General Medicine Genetics Microbiology Molecular Biology
Abstract
AbstractCandidatus Branchiomonas cysticola is recognized as the most prevalent bacterial agent causing epitheliocystis in Atlantic salmon (Salmo salar). Based on its partial 16S rRNA sequence, the bacterium has previously been found to be a member of Burkholderiales in the class Betaproteobacteria. Multilocus Sequence Analysis (MLSA) of the bacterium and 60 type strains of Betaproteobacteria using newly identified housekeeping genes (dnaK, rpoC, and fusA) and ribosomal subunit sequences (16S and 23S), instead supported the bacterium’s affiliation to Nitrosomodales. Taxonomic rank normalization by Relative Evolutionary Divergence (RED) showed the phylogenetic distinction between Cand. B. cysticola and its closest related type strain to be at the family level. A novel bacterial family named Branchiomonaceae has thus been proposed to include a monophyletic clade of Betaproteobacteria exclusively associated with epitheliocystis in fish.

Identification of housekeeping genes of Candidatus Branchiomonas cysticola associated with epitheliocystis in Atlantic salmon (Salmo salar L.)

Citation
Mjølnerød et al. (2022). Archives of Microbiology 204 (7)
Names (1)
Ca. Branchiomonas cystocola
Subjects
Biochemistry General Medicine Genetics Microbiology Molecular Biology
Abstract
AbstractCandidatus Branchiomonas cysticola is an intracellular, gram-negative Betaproteobacteria causing epitheliocystis in Atlantic Salmon (Salmo salar L.). The bacterium has not been genetically characterized at the intraspecific level despite its high prevalence among salmon suffering from gill disease in Norwegian aquaculture. DNA from gill samples of Atlantic salmon PCR positive for Cand. B. cysticola and displaying pathological signs of gill disease, was, therefore, extracted and subject to next-generation sequencing (mNGS). Partial sequences of four housekeeping (HK) genes (aceE, lepA, rplB, rpoC) were ultimately identified from the sequenced material. Assays for real-time RT-PCR and fluorescence in-situ hybridization, targeting the newly acquired genes, were simultaneously applied with existing assays targeting the previously characterized 16S rRNA gene. Agreement in both expression and specificity between these putative HK genes and the 16S gene was observed in all instances, indicating that the partial sequences of these HK genes originate from Cand. B. cysticola. The knowledge generated from the present study constitutes a major prerequisite for the future design of novel genotyping schemes for this bacterium.