TY - JOUR

T1 - Insights into the Morphology of Haplozoan Parasites (Dinoflagellata) using Confocal Laser Scanning Microscopy

AU - Angel, Phil

AU - Herranz, Maria

AU - Leander, Brian S.

N1 - Funding Information: We would like to thank N. Okamoto and G. Gavelis for discussions about the CLSM data. This research was performed in partial fulfilment of an MSc degree at UBC by PA. This work was supported by grants to BSL from the National Science and Engineering Research Council of Canada (NSERC 2019‐03986) and the Tula Foundation’s Hakai Institute. Publisher Copyright: © 2021 International Society of Protistologists

PY - 2021

Y1 - 2021

N2 - We describe new insights into the morphology and life history of the bizarre parasite Haplozoon axiothellae (Dinoflagellata) using light microscopy (LM), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Trophonts were isolated from the intestines of host maldanid polychaetes, Axiothella rubrocincta, collected from San Juan Island, Washington, USA. LM and SEM confirmed features previously observed, such as amphiesmal projections, mature and immature junctions between the nucleated compartments of the vermiform syncytium and visible polygonal alveoli. CLSM of adult trophonts fluorescently stained for DNA, tubulin, centrin, and plasma membrane demonstrated several new ultrastructural traits: (1) an extensive basket of parallel microtubules within the trophomere used for host attachment, (2) two physically separated MTOCs (i.e. putative pairs of basal bodies) beneath pores on the ventral side of each compartment, (3) robust mitotic and/or meiotic spindles associated with one to four nuclei in each compartment, (4) spindles with polar bodies that are disconnected from the MTOCs, (5) a centrin-stained fibril within the trophomeres that potentially functions to retract the motile stylet, and (6) cytokinesis in the posterior-most compartments. This study renames haplozoan compartments using the suffix “-mere” rather than “-cyte” (i.e. trophomere, gonomere, sporomere) to reflect their status within a single syncytium.

AB - We describe new insights into the morphology and life history of the bizarre parasite Haplozoon axiothellae (Dinoflagellata) using light microscopy (LM), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Trophonts were isolated from the intestines of host maldanid polychaetes, Axiothella rubrocincta, collected from San Juan Island, Washington, USA. LM and SEM confirmed features previously observed, such as amphiesmal projections, mature and immature junctions between the nucleated compartments of the vermiform syncytium and visible polygonal alveoli. CLSM of adult trophonts fluorescently stained for DNA, tubulin, centrin, and plasma membrane demonstrated several new ultrastructural traits: (1) an extensive basket of parallel microtubules within the trophomere used for host attachment, (2) two physically separated MTOCs (i.e. putative pairs of basal bodies) beneath pores on the ventral side of each compartment, (3) robust mitotic and/or meiotic spindles associated with one to four nuclei in each compartment, (4) spindles with polar bodies that are disconnected from the MTOCs, (5) a centrin-stained fibril within the trophomeres that potentially functions to retract the motile stylet, and (6) cytokinesis in the posterior-most compartments. This study renames haplozoan compartments using the suffix “-mere” rather than “-cyte” (i.e. trophomere, gonomere, sporomere) to reflect their status within a single syncytium.

KW - Axiothella

KW - Blastodiniales

KW - centrin

KW - dinoflagellate

KW - Haplozoon

KW - Maldanidiae

KW - spindle

KW - syncytium

KW - tubulin

U2 - 10.1111/jeu.12855

DO - 10.1111/jeu.12855

M3 - Journal article

C2 - 33894083

AN - SCOPUS:85105676673

VL - 68

JO - Journal of Eukaryotic Microbiology

JF - Journal of Eukaryotic Microbiology

SN - 1066-5234

IS - 4

M1 - e12855

ER -