A new species of cryptic cyanobacteria isolated from the epidermis of a bottlenose dolphin and as a bioaerosol

ABSTRACT

Two cyanobacterial strains, one collected from an epidermal mat present on a dead bottlenose dolphin and the other as a bioaerosol 457 m (1500 ft) above the river, were recently analysed from the St. Johns River, Jacksonville, Florida, USA. Both samples had major phenotypic plasticity which confused morphological identification. Amplicon sequencing of the 16S rRNA gene from the isolates revealed that both samples were closely aligned (branch bootstrap support = 100%) with the recently erected genus Komarekiella. Whole genome sequencing and phylogenetic construction also supported the isolation of a new species of cyanobacteria branching from the Nostoc clade. A total evidence approach of molecular, genetic, and ecological examination of these strains supported the erection of a new species, Komarekiella delphini-convector. A prior study determined that the dolphin with the epidermal mat had low levels of microcystins/nodularins (MCs/NODs) in the hepatic tissue. To investigate whether these toxins originated from the epidermal mat, immunoassay (ELISA) and 2-methyl-3-methoxy-4-phenylbutyric acid (MMPB) techniques were conducted on the original mat and subsequent culture samples. The results from both analyses were not conclusive. Genome mining was conducted and revealed diverse biosynthetic capabilities of this species but could not support toxin-producing potential. Further analytical work is required to determine the pathogenic capacity of this epizoic species.

KEYWORDS:

• 16S-ITS-23S rDNA
• Genome mining
• Secondary metabolites
• Tursiops truncatus

ACKNOWLEDGEMENTS

The authors thank Mark Aubel, Sarah Fuller and Kamil Cieslik for laboratory assistance in toxin analyses and methodology. We extend thanks to the Coastal Biology Flagship Program and the Environmental Center (University of North Florida) for funding. We thank Florida Fish and Wildlife Conservation Commission North East Field lab, Nadia Gordon, Allison Perna, and volunteers for their time and effort in sample collection and providing all available information for TtNEFL0813, TtNEFL1501 and TtNEFL1511. All photo-identification data were collected under authorization of NOAA Fisheries GA LOC 14157, 20377-01 and Permit 18182, as well as UNF’s IACUC (approval #11-003 and #13-006). The authors have no conflicts of interest to declare.

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Funding

This project was funded by the Internal Grant Agency of the Palacký University - Prf-2021-001, the University of North Florida Institute of Environmental Research and Education, the University of North Florida Department of Biology and UNF Coastal Biology Flagship Program.