USAP-DC

Overview: Antarctic biota face increasing stressors from warming oceans. A key question is: What will be the effect of warming waters on Antarctic biota? A gap in our knowledge is the identify of early harbingers of new stressors. In our recent field season, we unexpectedly discovered pink, wart-like neoplasms in Antarctic notothenioid fish, including Trematomus scotti (crowned notothen) and Nototheniops larseni (painted notothen). Neoplasms affected about 30% of T. scotti collected in Andvord Bay on the West Antarctic Peninsula and covered 10 to 30% of the bodies of affected individuals, usually in one contiguous patch. We collected samples from affected and apparently unaffected controls. We could not find evidence of any similar outbreak. Our overall goal is to learn the biological origins of this neoplasm and how it affects cellular function and organismal physiology. Intellectual Merit: Aim 1: Pathogenic agents. Aim 1a: To test the hypothesis that a virus causes the neoplasm. Methods involve isolating and sequencing viral nucleic acids from neoplasms and from unaffected skin and comparing sequences to known viruses. Aim 1b: To test the hypothesis that neoplasms are hosts to parasites not present in healthy skin. Methods include tissue sections and DNA sequencing to find evidence of parasitic organisms. Significance: achieving Aim 1 will narrow down possible etiological agents. An untested possibility is that environmental contaminants cause the condition; exploring that hypothesis would require further sampling outside the limits of an EAGER proposal. Aim 2: Cell-level pathology. Aim 2a: To test the hypothesis that the histopathology of the neoplasms is similar to other known skin neoplasias; alternatively, it might be a previously unknown type of neoplasia. Methods involve the examination of histological sections to identify pathology-specific characters. Aim 2b: To find effects of neoplasms on cell function. Methods involve performing whole-genome transcriptomics of affected and normal skin by RNA-seq and aligning reads to a T. scotti reference genome. Significance: achieving Aim 2 will define the cell biology and gene-expression phenotypes of the neoplasia, thus suggesting mechanisms that cause it. [Note: NSF deleted funds specifically to achieve the Aim 3, which nevertheless appears here to represent the original proposal.] Aim 3: Organismal pathology. Aim 3a: To test the hypothesis that the neoplasm has adverse effects on growth and physiology. Methods are to perform morphometrics in fish with neoplasms compared to age-matched controls from otolith studies. Aim 3b: To test the hypothesis that the neoplasia affects reproductive traits. Methods compare reproductive effort in affected and unaffected individuals. Significance: if the neoplasia has little consequences on growth and reproduction, our worry about its spread will be lessened, but if it is harmful, then Antarctic ecology, which largely depends on notothenioid fish, might be in danger. Achieving Aims 1-3 will advance knowledge by identifying the causes of a neoplasia outbreak in Antarctic fish. Work is potentially transformative because it might represent an early sign of Antarctic fish responses to the stress of global climate change. Proposed work would be the first to investigate a neoplasia outbreak in Antarctic fish. We will assess the project’s success by whether we identify a causative agent and its effects on physiology. Broader Impacts: Aim 4: Publicizing the neoplasia. We aim to raise awareness of the outbreak and publicize its distinct diagnostic features, including assays to detect it, by contributing to groups that track Antarctic ecosystems. Aim 5: Inclusion. We will involve underrepresented groups in scientific research with authentic research experiences. Achieving Aims 4 and 5 will benefit society because they will disseminate to scientific and lay communities a potential early-warning system for the effects of an apparently new neoplasia affecting, at least locally, a large proportion of a fish population. Dissemination will stir research to determine whether this neoplasia outbreak is an isolated event or is becoming a general phenomenon, and thus a concern for Antarctic ecosystems. Proposed research will enhance research infrastructure by providing tools to identify the neoplasia. Finally, the project will broaden access to research careers by exposing underserved high school students and undergraduates to an exciting live research project.

Person	Role
Postlethwait, John	Investigator and contact
Varsani, Arvind	Co-Investigator
Desvignes, Thomas	Co-Investigator

Antarctic Organisms and Ecosystems

Award # 1947040

USAP-1947040_1

None in the Database

Repository	Title (link)	Format(s)	Status
MorphoSource	Trematomus scotti with X-cell xenomas	Not Provided	exist
GenBank	18 SSU rDNA type sequences for Notoxcellia coronata (nov. sp.)	Not Provided	exist
GenBank	18 SSU rDNA type sequences for Notoxcellia picta (nov. sp.)	Not Provided	exists
NCBI SRA	Raw Illumina sequencing reads from skin tumors and visually healthy skins from Trematomus scotti and Nototheniops larseni	Not Provided	exists
USAP-DC	Phylogenetic Analysis of Notoxcellia species.	Not Provided	exists
USAP-DC	Temperature profiles at five fishing locations on the West Antarctic Peninsula during austral fall 2018.	Not Provided	exists
USAP-DC	Morphological and pathological data of Trematomus scotti specimens captured on May 30th, 2018 in Andvord Bay.	Not Provided	exists
USAP-DC	Fish pictures and skin pathology of X-cell infection in Trematomus scotti.	Not Provided	exists
USAP-DC	Histopathology of X-cell xenomas in Trematomus scotti and Nototheniops larseni.	Not Provided	exists
USAP-DC	Metagenomic analysis of apparently healthy and tumor samples using Kaiju software	Excel	exists
USAP-DC	microMRI analyses of Trematomus scotti Tsco_18_08 with X-cell xenomas	PDF, AVI	exists
USAP-DC	In situ hybridization of X-cell and host fish 18S SSU rRNA in alternate sections of tumor xenomas.	Not Provided	exists

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2. Ashique, A. M., Atake, O. J., Ovens, K., Guo, R., Pratt, I. V., Detrich, H. W., … Eames, B. F. (2021). Bone microstructure and bone mineral density are not systemically different in Antarctic icefishes and related Antarctic notothenioids. Journal of Anatomy. (doi:10.1111/joa.13537)
3. Hotaling, S., Borowiec, M.L., Lins, L.S.F., Desvignes, T., Kelley, J.L. (2021) The biogeographic history of eelpouts and related fishes: Linking phylogeny, environmental change, and patterns of dispersal in a globally distributed fish group. Molecular Phylogenetics and Evolution (doi:10.1016/j.ympev.2021.107211)
4. Beck, E.A., Healey, H.M., Small, C.M., Currey, M.C., Desvignes, T., Cresko, W.A., Postlethwait, J.H. (2022) Advancing human disease research with fish evolutionary mutant models. Trends in genetics (doi:10.1016/j.tig.2021.07.002)
5. Desvignes, T., Postlethwait, J.H. & Konstantinidis, P. (2020) Biogeography of the Antarctic dragonfishes Acanthodraco dewitti and Psilodraco breviceps with re-description of Acanthodraco dewitti larvae (Notothenioidei: Bathydraconidae). Polar Biol 43, 565–572. (doi:10.1007/s00300-020-02661-y)
6. Caccavo, J.A., Christiansen, H., Constable, A.J., Ghigliotti, L., Trebilco, R., Brooks, C.M., Cotte, C., Desvignes, T., Dornan, T., Jones, C.D., Koubbi, P., Saunders, R.A., Strobel, A., Vacchi, M., van de Putte, A.P., Walters, A., Waluda, C.M., Woods, B.L., Xavier, J.C. (2021) Productivity and Change in Fish and Squid in the Southern Ocean. Frontiers in Ecology and Evolution. 9:624918
7. Fischhoff, I. R., Castellanos, A. A., Rodrigues, J. P. G. L. M., Varsani, A., & Han, B. A. (2021). Predicting the zoonotic capacity of mammals to transmit SARS-CoV-2. Proceedings of the Royal Society B: Biological Sciences, 288(1963). (doi:10.1098/rspb.2021.1651)
8. Desvignes, T., Lauridsen, H., Valdivieso, A., Fontenele, R.S., Kraberger, S., Murray, K.N., Le François, N.R., Detrich, H.W., Kent, M.L., Varsani, A., Postlethwait, J.H. (2022). A parasite outbreak in notothenioid fish in an Antarctic fjord. iScience. (doi:10.1016/j.isci.2022.104588)
9. Hotaling, S., Desvignes, T., Sproul, J.S., Lins, L.S.F., Kelley, J.L. (2022) Pathways to polar adaptation in fishes revealed by long-read sequencing. Molecular Ecology. (doi:10.1111/mec.16501)
10. DaMommio, C., Postlethwait, J.H., Desvignes, T. (2022) A mysterious disease in Antarctic fish (https://blogs.uoregon.edu/antarcticxcell/). (doi:10.3389/fevo.2021.624918)