Researcher Database

Kevin Wakeman
Institute for the Advancement of Higher Education
Assistant Professor

Researcher Profile and Settings

Affiliation

  • Institute for the Advancement of Higher Education

Job Title

  • Assistant Professor

Degree

  • PHD(University of British Columbia)

J-Global ID

Profile

  • My research interests broadly revolve around exploring the biodiversity and evolution single-celled marine microeukaryotes (protists). Currently, I am working on alveolates, a collective of organisms that include notorious apicompelxan pathogens such as causative agent of malaria, as well as dinoflagellate microalgae that produce harmful algal blooms (red tides) and shellfish poisoning. My goal is to apply this work to ecological and economical significant systems such as coral reef biology and shellfish fisheries in the oceans around Japan and globally.

Research Interests

  • Phylogenomics   Evolution   Systematics   Phylogenetics   Marine Biology   Biodiversity   

Research Areas

  • Life sciences / Biodiversity and systematics
  • Life sciences / Evolutionary biology
  • Life sciences / Morphology, anatomy
  • Life sciences / Cell biology
  • Life sciences / Molecular biology

Academic & Professional Experience

  • 2016/03 - Today Institute for the Advancement of Higher Education (ISP)/Graduate School of Science, Hokkaido University Biology Assistant Professor
  • 2015/04 - 2016/02 University of Tokyo Center for Global Communication Strategies Assistant Professor
  • 2013/01 - 2015/03 Okinawa Institute of Science and Technology Researcher/Research Specialist
  • 2010/06 - 2013/12 University of British Coloumbia Zoology Department Teaching Assistant

Education

  • 2010/06 - 2013/12  University of British Columbia  Zoology Department  PhD
  • 2005/09 - 2009/12  Humboldt State University  German  BA
  • 2005/09 - 2009/12  Humboldt State University  Biology  BSc

Association Memberships

  • International Society of Protistologists   

Research Activities

Published Papers

  • Kevin C Wakeman
    Protist 171 (1) 125710 - 125710 2020/02 [Refereed][Not invited]
     
    This study set out to bolster morphological and molecular datasets of marine gregarine apicomplexans. Gregarines were sampled from the Sea of Japan and Northwest Pacific from cirratuliform polychaetes (Acrocirridae, Cirratulidae, and Flabelligeridae), as well as sipunculids. Trophozoites (feeding stages) were gathered for identification using light microscopy, scanning electron microscopy, and transmission electron microscopy. Cells were also collected for molecular phylogenetic analysis using 18S rDNA and 28S rDNA. As a result, three new species of Selenidium, S. planusae n. sp., S. validusae n. sp., and S. pyroidea n. sp. were described, and additional morphological and genetic data were gathered for an existing species, S. orientale; and Trollidium was established as a new genus. Trollidium akkeshiense n. gen. n. sp. possessed a unique, unsymmetrical organization of microtubules running the longitudinal length of one side of the trophozoite, corresponding to a zig-zag pattern of epicytic (surface) folds, and a flicking pattern of movement. Phylogenetic analyses of 18S rDNA and 28S rDNA showed that these portions of the ribosomal operon are able to resolve some relationships among Selenidium, while other lineages including Trollidium akkeshiense n. gen. n. sp. appeared to be highly influenced by long branch attraction. High evolutionary rates along the ribosomal operon of gregarines may hinder this marker from resolving deeper nodes among early apicomplexans.
  • Del Campo J, Pons MJ, Herranz M, Wakeman KC, Del Valle J, Vermeij MJA, Leander BS, Keeling PJ
    Environmental microbiology 21 (10) 3855 - 3861 1462-2912 2019/10 [Refereed][Not invited]
  • Siaden Luis E. Chira, Wakeman Kevin C, Webb Stephen C, Hasegawa Kazunori, Kajihara Hiroshi
    ZOOTAXA 4551 (4) 415 - 431 1175-5326 2019/02/04 [Refereed][Not invited]
  • Gregory S Gavelis, Maria Herranz, Kevin C Wakeman, Christina Ripken, Satoshi Mitarai, Gillian H Gile, Patrick J Keeling, Brian S Leander
    Scientific reports 9 (1) 839 - 839 2019/01/29 [Refereed][Not invited]
     
    Dinoflagellates are some of the most common eukaryotic cells in the ocean, but have very unusual nuclei. Many exhibit a form of closed mitosis (dinomitosis) wherein the nuclear envelope (NE) invaginates to form one or more trans-nuclear tunnels. Rather than contact spindles directly, the chromatids then bind to membrane-based kinetochores on the NE. To better understand these unique mitotic features, we reconstructed the nuclear architecture of Polykrikos kofoidii in 3D using focused ion beam scanning electron microscopy (FIB-SEM) in conjunction with high-pressure freezing, freeze-substitution, TEM, and confocal microscopy. We found that P. kofoidii possessed six nuclear tunnels, which were continuous with a reticulating network of membranes that has thus far gone unnoticed. These membranous extensions interconnect the six tunnels while ramifying throughout the nucleus to form a "nuclear net." To our knowledge, the nuclear net is the most elaborate endomembrane structure described within a nucleus. Our findings demonstrate the utility of tomographic approaches for detecting 3D membrane networks and show that nuclear complexity has been underestimated in Polykrikos kofoidii and, potentially, in other dinoflagellates.
  • Suong NT, Banks JC, Fidler A, Jeffs A, Wakeman KC, Webb S
    Diseases of aquatic organisms 132 (3) 181 - 189 0177-5103 2019/01 [Refereed][Not invited]
  • Aika Yamaguchi, Kevin C. Wakeman, Mona Hoppenrath, Takeo Horiguchi, Hiroshi Kawai
    Phycologia 57 (6) 630 - 640 0031-8884 2018/09 [Refereed][Not invited]
  • Suong NT, Banks JC, Webb SC, Jeffs A, Wakeman KC, Fidler A
    Diseases of aquatic organisms 129 (3) 199 - 205 0177-5103 2018/08 [Refereed][Not invited]
  • Iritani D, Horiguchi T, Wakeman KC
    The Journal of eukaryotic microbiology 65 (5) 637 - 647 1066-5234 2018/07 [Refereed][Not invited]
  • Kevin C. Wakeman, Aika Yamaguchi, Takeo Horiguchi
    Protist 169 (3) 333 - 350 1618-0941 2018/07/01 [Refereed][Not invited]
     
    This study describes a novel species of Haplozoon, H. ezoense n. sp., a dinoflagellate parasite isolated from the intestines of Praxillella pacifica (Polychaeta). Trophonts (feeding stages) of H. ezoense n. sp. were isolated and studied with scanning and transmission electron microscopy, and molecular phylogenetic analyses was performed using 18S rDNA and 28S rDNA. Trophonts had an average length of 120 μm, and were linear, forming a single longitudinal row comprising a trophocyte with a stylet, an average of 14 gonocytes (width = 10 μm), and bulbous cells that we concluded were likely sporocytes. The surface of H. ezoense n. sp. was covered with projections of the amphiesma. Sections viewed under TEM revealed multiple triple membrane-bound organelles reminiscent of relic non-photosynthetic plastids within the gonocytes. Haplozoon ezoense n. sp., H. praxillellae, and H. axiothellae formed a well-supported clade in the 18S rDNA datasets. The sequences of H. ezoense n. sp. differed from H. praxillellae, a species of Haplozoon isolated from the same host species in the Northeast Pacific, at 88/1,748 bases and 155/1,752 bases from H. axiothellae. Concatenated 18S rDNA and 28S rDNA datasets were unable to resolve the deeper relationships of Haplozoon in the context of dinoflagellates.
  • Kevin C. Wakeman, Akinori Yabuki, Katsunori Fujikura, Ko Tomikawa, Takeo Horiguchi
    Journal of Eukaryotic Microbiology 65 (3) 372 - 381 1550-7408 2018/05/01 [Refereed][Not invited]
     
    In an effort to broaden our understanding of the biodiversity and distribution of gregarines infecting crustaceans, this study describes two new species of gregarines, Thiriotia hyperdolphinae n. sp. and Cephaloidophora oradareae n. sp., parasitizing a deep sea amphipod (Oradarea sp.). Amphipods were collected using the ROV Hyper-Dolphin at a depth of 855 m while on a cruise in Sagami Bay, Japan. Gregarine trophozoites and gamonts were isolated from the gut of the amphipod and studied with light and scanning electron microscopy, and phylogenetic analysis of 18S rDNA. Thiriotia hyperdolphinae n. sp. was distinguished from existing species based on morphology, phylogenetic position, as well as host niche and geographic locality. Cephaloidophora oradareae n. sp. distinguished itself from existing Cephaloidophora, based on a difference in host (Oradarea sp.), geographic location, and to a certain extent morphology. We established this latter new species with the understanding that a more comprehensive examination of diversity at the molecular level is necessary within Cephaloidophora. Results from the 18S rDNA molecular phylogeny showed that T. hyperdolphinae n. sp. was positioned within a clade consisting of Thiriotia spp., while C. oradareae n. sp. grouped within the Cephaloidophoridae. Still, supplemental genetic information from gregarines infecting crustaceans will be needed to better understand relationships within this group of apicomplexans.
  • Davis Iritani, Kevin C. Wakeman, Brian S. Leander
    Journal of Eukaryotic Microbiology 65 (2) 211 - 219 1550-7408 2018/03/01 [Refereed][Not invited]
     
    Gregarine apicomplexans are unicellular parasites commonly found in the intestines and coeloms of invertebrate hosts. Traits associated with the conspicuous feeding stage of gregarines, known as the trophozoite, have been used in combination with molecular phylogenetic data for species delimitation and the reconstruction of evolutionary history. Trophozoite morphology alone is often inadequate for inferring phylogenetic relationships and delimiting species due to frequent cases of high intraspecific variation combined with relatively low interspecific variation. The current study combined morphological data with small subunit (SSU) rDNA sequences to describe and establish two novel marine gregarine species isolated from the intestine of a polychaete host Lumbrineris inflata collected in British Columbia (Canada): Paralecudina anankea n. sp. and Lecudina caspera n. sp. The sister species to the host is Lumbrineris japonica, which can be found on the opposite side of the Pacific Ocean (Japan) and contains two different species of gregarine parasites: Paralecudina polymorpha and Lecudina longissima. Molecular phylogenetic analyses placed P. anankea n. sp. as the sister species to P. polymorpha and L. caspera n. sp. as the sister species to L. longissima. This phylogenetic pattern demonstrates a co-evolutionary history whereby speciation of the host (Lumbrineris) corresponds with simultaneous speciation of the two different lineages of intestinal gregarines (Paralecudina and Lecudina).
  • Kevin C. Wakeman, Mona Hoppenrath, Aika Yamaguchi, Greg S. Gavelis, Brian S. Leander, Hisayoshi Nozaki
    Phycologia 57 (2) 209 - 222 2330-2968 2018/01/11 [Refereed][Not invited]
     
    We isolated Plagiodinium belizeanum into clonal culture from the Pacific island of Okinawa (Japan) and characterized it using a combination of light microscopy, scanning electron microscopy, transmission electron microscopy and 18S/28S ribosomal (r) gene sequences. Although molecular phylogenetic analyses of 18S rDNA and 28S rDNA sequences were unable to resolve the phylogenetic position of P. belizeanum within dinoflagellates, the ultrastructural data provided some new traits for the species. For instance, double-membrane-bound vesicles, distinct from the mitochondria, were interpreted as autolysosomes containing electron-dense virus particles. The thecal plate pattern was Po 10 0a 50 0 5(6)C 4S 50 0 0 0p 10 0 0 0, which is slightly different from the original description in having an additional epithecal plate and four sulcal plates. The laterally flattened cells were 22-34 lm long, 11-13 lm deep, and 15-18 lm wide and contained a peridinin-type plastid with lobes radiating from a central pyrenoid that lacked starch sheaths and was traversed by stacks of thylakoids. This isolate represents the first record of the species in Japan, and the new ultrastructural and DNA sequence data were used to emend the species description.
  • Nguyen Thao Suong, Stephen Webb, Jonathan Banks, Kevin C. Wakeman, Henry Lane, Andrew Jeffs, Cara Brosnahan, Brian Jones, Andrew Fidler
    DISEASES OF AQUATIC ORGANISMS 127 (1) 1 - 9 0177-5103 2017/12 [Refereed][Not invited]
     
    Apicomplexa is a large phylum of parasitic protists renowned for significant negative health impacts on humans and livestock worldwide. Despite the prevalence and negative impacts of apicomplexans across many animal groups, relatively little attention has been given to apicomplexan parasites of invertebrates, especially marine invertebrates. Previous work has reported an apicomplexan parasite 'X' (APX), a parasite that has been histologically and ultrastructurally identified from the commercially important flat oyster Ostrea chilensis in New Zealand. This apicomplexan may exacerbate host vulnerability to the infectious disease bonamiosis. In this study, we report 18S rRNA sequences amplified from APX-infected O. chilensis tissues. Phylogenetic analyses clearly established that the 18S sequences were of apicomplexan origin; however, their detailed relationship to known apicomplexan groups is less resolved. Two specific probes, designed from the putative APX 18S rRNA sequence, co-localised with APX cells in in situ hybridisations, further supporting our hypothesis that the 18S sequences were from APX. These sequences will facilitate the future development of inexpensive and sensitive molecular diagnostic tests for APX, thereby assisting research focussed on the biology and ecology of this organism and its role in morbidity and mortality of O. chilensis.
  • Gregory S. Gavelis, Kevin C. Wakeman, Urban Tillmann, Christina Ripken, Satoshi Mitarai, Maria Herranz, Suat Oezbek, Thomas Holstein, Patrick J. Keeling, Brian S. Leander
    SCIENCE ADVANCES 3 (3) e1602552  2375-2548 2017/03 [Refereed][Not invited]
     
    We examine the origin of harpoon-like secretory organelles (nematocysts) in dinoflagellate protists. These ballistic organelles have been hypothesized to be homologous to similarly complex structures in animals (cnidarians); but we show, using structural, functional, and phylogenomic data, that nematocysts evolved independently in both lineages. We also recorded the first high-resolution videos of nematocyst discharge in dinoflagellates. Unexpectedly, our data suggest that different types of dinoflagellate nematocysts use two fundamentally different types of ballistic mechanisms: one type relies on a single pressurized capsule for propulsion, whereas the other type launches 11 to 15 projectiles from an arrangement similar to a Gatling gun. Despite their radical structural differences, these nematocysts share a single origin within dinoflagellates and both potentially use a contraction-based mechanism to generate ballistic force. The diversity of traits in dinoflagellate nematocysts demonstrates a stepwise route by which simple secretory structures diversified to yield elaborate subcellular weaponry.
  • Andrei Diakin, Kevin C. Wakeman, Andrea Valigurova
    JOURNAL OF EUKARYOTIC MICROBIOLOGY 64 (1) 56 - 66 1066-5234 2017/01 [Refereed][Not invited]
     
    A novel species of aseptate eugregarine, Ganymedes yurii sp. n., is described using microscopic and molecular approaches. It inhabits the intestine of Gondogeneia sp., a benthic amphipod found along the shore of James Ross Island, Weddell Sea, Antarctica. The prevalence of the infection was very low and only a few caudo-frontal syzygies were found. Morphologically, the new species is close to a previously described amphipod gregarine, Ganymedes themistos, albeit with several dissimilarities in the structure of the contact zone between syzygy partners, as well as other characteristics. Phylogenetic analysis of the 18S rDNA from G. yurii supported a close relationship between these species. These two species were grouped with other gregarines isolated from crustaceans hosts (Cephaloidophoroidea); however, statistical support throughout the clade of Cephaloidophoroidea gregarines was minimal using the available dataset.
  • Aika Yamaguchi, Sadaaki Yoshimatsu, Mona Hoppenrath, Kevin C. Wakeman, Hiroshi Kawai
    PROTIST 167 (6) 568 - 583 1434-4610 2016/12 [Refereed][Not invited]
     
    The genus Amphidiniopsis is a benthic (sand-dwelling) lineage of thecate dinoflagellates, containing 19 morphologically diverse species. Past work has shown that some Amphidiniopsis species form a Glade with the sand-dwelling Herdmania litoralis as well as some planktonic species in the family Protoperidiniaceae (i.e. the Monovela group). Still, our contemporary knowledge regarding Amphidiniopsis is limited, compared to the Protoperidiniaceae. To this end, we obtained 18S rDNA data from seven Amphidiniopsis species and a part of the 28S rDNA from four Amphidiniopsis species, with the goal of improving our understanding of phylogenetic relationships among Amphidiniopsis and the Monovela group. Results from the molecular phylogenetic analyses showed that Amphidiniopsis spp., with the exception of A. cf. arenaria, H. litoralis, and members within the Monovela group formed a single Glade. Within the Glade, relationships among Amphidiniopsis spp. and the Monovela group were more complicated - some subclades contained both representatives of Amphidiniopsis and the Monovela group. Our study suggests that habitat (benthic or planktonic), as well as traditionally used, general morphological characteristics, do not reflect molecular phylogenetic relationships, and that the taxonomy of the sand-dwelling genus Amphidiniopsis, and the planktonic family Protoperidiniaceae, should be reconsidered simultaneously. (C) 2016 Elsevier GmbH. All rights reserved.
  • Fernando Gomez, Kevin C. Wakeman, Aika Yamaguchi, Hisayoshi Nozaki
    ACTA PROTOZOOLOGICA 55 (4) 239 - 248 0065-1583 2016 [Refereed][Not invited]
     
    The dinoflagellate genera Oxytoxum and Corythodinium that account for more than fifty species are widespread in warm oceans. These genera have been considered synonyms and thecal plate designations varied among authors. Several planktonic and sand-dwelling genera have been placed within the Oxytoxaceae. We obtained the first molecular data based on small subunit (SSU) rRNA gene sequences of Oxytoxum and Corythodinium, including the type species (O. scolopax and C. tessellatum) and C. frenguellii and C. cristatum. The three species of Corythodinium branched together a strong support [bootstrap (BP) of 98%]. This formed a sister clade with moderate support (BP 75%) with O. scolopax that supported the generic split. Oxytoxaceae should exclusively remain for Oxytoxum and Corythodinium, as an independent group, unrelated to any other known dinoflagellate. Oxytoxum was characterized by spindle-shaped cells with an anterior narrow epitheca, an apical spine and little cingular displacement. Corythodinium exhibits relatively broad cell shapes, with wider epitheca and greater cingular displacement, and an obovate or pentangular anterior sulcal plate that noticeably indented the epitheca. This suggested the need of new combinations for species that were described as Oxytoxum and possessed the characteristics of Corythodinium.
  • Sonja Rueckert, Kevin C. Wakeman, Holger Jenke-Kodama, Brian S. Leander
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 65 (8) 2598 - 2614 1466-5026 2015/08 [Refereed][Not invited]
     
    The eugregarines are a group of apicomplexan parasites that mostly infect the intestines of invertebrates. The high level of morphological variation found within and among species of eugregarines makes it difficult to find consistent and reliable traits that unite even closely related lineages. Based mostly on traits observed with light microscopy, the majority of described eugregarines from marine invertebrates has been classified into a single group, the Lecudinidae. Our understanding of the overall diversity and phylogenetic relationships of lecudinids is very poor, mainly because only a modest amount of exploratory research has been done on the group and very few species of lecudinids have been characterized at the molecular phylogenetic level. In an attempt to understand the diversity of marine gregarines better, we surveyed lecudinids that infect the intestines of Pacific ascidians (i.e. sea squirts) using ultrastructural and molecular phylogenetic approaches; currently, these species fall within one genus, Lankesteria. We collected lecudinid gregarines from six ascidian host species, and our data demonstrated that each host was infected by a different species of Lankesteria: (i) Lankesteria hesperidiiformis sp. nov., isolated from Distaplia occidentalis, Lankesteria metandrocarpae sp. nov., isolated from Metandrocarpa taylori, (iii) Lankesteria halocynthiae sp. nov., isolated from Halocynthia aurantium, (iv) Lankesteria herdmaniae sp. nov., isolated from Herdmania momus, (v) Lankesteria cf. ritterellae, isolated from Ritterella rubra, and (vi) Lankesteria didemni sp. nov., isolated from Didemnum vexillum. Visualization of the trophozoites with scanning electron microscopy showed that four of these species were covered with epicytic folds, whereas two of the species were covered with a dense pattern of epicytic knobs. The molecular phylogenetic data suggested that species of Lankesteria with surface knobs form a clade that is nested within a paraphyletic assemblage species of Lankesteria with epicytic folds.
  • Kevin C. Wakeman, Aika Yamaguchi, Michael C. Roy, Holger Jenke-Kodama
    HARMFUL ALGAE 44 8 - 19 1568-9883 2015/04 [Refereed][Not invited]
     
    Marine benthic dinoflagellates within the genus Coolia have been reported to produce natural products, some of which are known to be toxic (i.e., cooliatoxin). To date, five species of Coolia have been reported in tropical and temperate waters around the world; however, very few studies have combined detailed morphological and molecular data with chemical analyses. In this study, a clonal culture of Coolia malayensis was isolated and mass cultivated from a coral reef on the island of Okinawa, Japan. Analysis of the thecal plate morphology and molecular phylogeny from 28S rDNA strongly supported the close relationship between this new isolate of C. malayensis from Okinawa and other isolates of C malayensis from around the world. Following methanol extraction of 250 L of Mass culture, chemical analyses using NanoLiquid chromatography mass spectrometry revealed the mass profiles of water-soluble and ethyl acetate-soluble parts. High-resolution mass spectrometry derived the molecular formulas of three novel disulphated polyether analogs of yessotoxin (C56H78O18S2 1102.4 (Compound 1), C57H80O18S2 1116.4 (Compound 2), and C57H78O19S2 1130.4 (Compound 3)); two potential homologous compounds (Compounds 4 and 5) were also observed on the high-resolution mass, albeit with low signal intensity. The five compounds in the C malayensis from Okinawa are composed of less oxygen, compared to cooliatoxin and other analogs of yessotoxin, suggesting the metabolites produced by C malayensis are unique to those previously reported from other strains of Coolia. (C) 2015 Elsevier B.V. All rights reserved.
  • Kevin C. Wakeman, Matthew B. Heintzelman, Brian S. Leander
    PROTIST 165 (4) 493 - 511 1434-4610 2014/08 [Refereed][Not invited]
     
    Gregarine apicomplexans are a diverse group of single-celled parasites that have feeding stages (trophozoites) and gamonts that generally inhabit the extracellular spaces of invertebrate hosts living in marine, freshwater, and terrestrial environments. Inferences about the evolutionary morphology of gregarine apicomplexans are being incrementally refined by molecular phylogenetic data, which suggest that several traits associated with the feeding cells of gregarines arose by convergent evolution. The study reported here supports these inferences by showing how molecular data reveals traits that are phylogenetically misleading within the context of comparative morphology alone. We examined the ultrastructure and molecular phylogenetic positions of two gregarine species isolated from the spaghetti worm Thelepus japonicus: Selenidium terebellae Ray 1930 and S. melongena n. sp. The ultrastructural traits of S. terebellae were very similar to other species of Selenidium sensu stricto, such as having vermiform trophozoites with an apical complex, few epicytic folds, and a dense array of microtubules underlying the trilayered pellicle. By contrast, S. melongena n. sp. lacked a comparably discrete assembly of subpellicular microtubules, instead employing a system of fibrils beneath the cell surface that supported a relatively dense array of helically arranged epicytic folds. Molecular phylogenetic analyses of small subunit rDNA sequences derived from single-cell PCR unexpectedly demonstrated that these two gregarines are close sister species. The ultrastructural differences between these two species were consistent with the fact that S. terebellae infects the inner lining of the host intestines, and S. melongena n. sp. primarily inhabits the coelom, infecting the outside wall of the host intestine. Altogether, these data demonstrate a compelling case of niche partitioning and associated morphological divergence in marine gregarine apicomplexans. (C) 2014 Elsevier GmbH. All rights reserved.
  • Kevin C. Wakeman, James D. Reimer, Holger Jenke-Kodama, Brian S. Leander
    JOURNAL OF EUKARYOTIC MICROBIOLOGY 61 (4) 343 - 353 1066-5234 2014/07 [Refereed][Not invited]
     
    Gregarines are a diverse group of apicomplexan parasites with a conspicuous extracellular feeding stage, called a "trophozoite", that infects the intestines and other body cavities of invertebrate hosts. Although the morphology of trophozoites is very diverse in gregarines as a whole, high degrees of intraspecific variation combined with relatively low degrees of interspecific variation make the delimitation of different species based on trophozoite morphology observed with light microscopy difficult. The coupling of molecular phylogenetic data with comparative morphology has shed considerable light onto the boundaries and interrelationships of different gregarine species. In this study, we isolated a novel marine gregarine from the hepatic region of a Pacific representative of the hemichordate Glossobalanus minutus, and report the first ultrastructural and molecular data from any gregarine infecting this distinctive group of hosts. Molecular phylogenetic analyses of an SSU rDNA sequence derived from two single-cell isolates of this marine gregarine demonstrated a strong and unexpected affiliation with a clade of terrestrial gregarines (e. g. Gregarina). This molecular phylogenetic data combined with a comparison of the morphological features in previous reports of gregarines collected from Atlantic representatives of G. minutus justified the establishment of a new binomial for the new isolate, namely Caliculium glossobalani n. gen. et sp. The molecular phylogenetic analyses demonstrated a clade of terrestrial gregarines associated with a sequence acquired from a marine species, which suggest that different groups of terrestrial/freshwater gregarines evolved independently from marine ancestors.
  • Kevin C. Wakeman, Brian S. Leander
    JOURNAL OF EUKARYOTIC MICROBIOLOGY 60 (5) 514 - 525 1066-5234 2013/09 [Refereed][Not invited]
     
    Selenidium is a genus of gregarine parasites that infect the intestines of marine invertebrates and have morphological, ecological, and motility traits inferred to reflect the early evolutionary history of apicomplexans. Because the overall diversity and phylogenetic position(s) of these species remain poorly understood, we performed a species discovery survey of Selenidium from tube-forming polychaetes. This survey uncovered five different morphotypes of trophozoites (feeding stages) living within the intestines of three different polychaete hosts. We acquired small subunit (SSU) rDNA sequences from single-cell (trophozoite) isolates, representing all five morphotypes that were also imaged with light and scanning electron microscopy. The combination of molecular, ecological, and morphological data provided evidence for four novel species of Selenidium, two of which were established in this study: Selenidium neosabellariae n. sp. and Selenidium sensimae n. sp. The trophozoites of these species differed from one another in the overall shape of the cell, the specific shape of the posterior end, the number and form of longitudinal striations, the presence/absence of transverse striations, and the position and shape of the nucleus. A fifth morphotype of Selenidium, isolated from the tube worm Dodecaceria concharum, was inferred to have been previously described as Selenidium cf. echinatum, based on general trophozoite morphology and host association. Phylogenetic analyses of the SSU rDNA sequences resulted in a robust clade of Selenidium species collected from tube-forming polychaetes, consisting of the two new species, the two additional morphotypes, S. cf. echinatum, and four previously described species (Selenidium serpulae, Selenidium boccardiellae, Selenidium idanthyrsae, and Selenidium cf. mesnili). Genetic distances between the SSU rDNAsequences in this clade distinguished closely related and potential cryptic species of Selenidium that were otherwise very similar in trophozoite morphology.
  • Kevin C. Wakeman, Brian S. Leander
    MARINE BIODIVERSITY 43 (2) 133 - 147 1867-1616 2013/06 [Refereed][Not invited]
     
    Environmental PCR surveys of small-subunit (SSU) rDNA sequences are powerful approximations for the overall diversity of microbial eukaryotes (protists) living in specific marine habitats. However, many environmental DNA sequences generated from these approaches have unknown cellular origins because they are not closely related to other sequences that were generated directly from fully characterized, identified organisms. The unidentified sequences from marine environments tend to belong to poorly understood groups of apicomplexan parasites, especially gregarines. Single-cell PCR (SC-PCR) approaches on newly discovered gregarines provide the evidence necessary for determining the cellular identities of SSU rDNA sequence clades. In this study, the trophozoites of four novel gregarine morphotypes were isolated from the intestines of two different species of capitellid polychaetes collected from the eastern Pacific Ocean (British Columbia, Canada). The trophozoites of each morphotype were characterized using light microscopy, scanning electron microscopy, and SSU rDNA sequences amplified from four, single-cell isolates from each of the four novel morphotypes described in this study (16 new SSU rDNA sequences in total). Molecular phylogenetic analyses demonstrated five robust subclades within a more inclusive clade that contained all 16 new sequences and 5 environmental SSU rDNA sequences. The combination of SC-PCR approaches, molecular phylogenetic analyses, and comparative morphology (1) illustrate the utility of SC-PCR approaches for distinguishing between different gregarine species, (2) demonstrate the cellular identity of a previously unidentified environmental SSU rDNA sequence clade, and (3) enable us to establish four new species within one novel genus: Polyplicarium lacrimae n. gen. et sp. (type species), P. curvarae n. gen. et sp., P. translucidae n. gen. et sp., and P. citrusae n. gen. et sp.
  • Sonja Rueckert, Kevin C. Wakeman, Brian S. Leander
    JOURNAL OF EUKARYOTIC MICROBIOLOGY 60 (2) 121 - 136 1066-5234 2013/03 [Refereed][Not invited]
     
    Marine gregarines are poorly understood apicomplexan parasites with large trophozoites that inhabit the body cavities of marine invertebrates. Two novel species of gregarines were discovered in polychaete hosts collected in Canada and Japan. The trophozoites of Trichotokara japonica n. sp. were oval to rhomboidal shaped, and covered with longitudinal epicytic folds with a density of six to eight folds/micron. The nucleus was situated in the middle of the cell, and the mucron was elongated and covered with hair-like projections; antler-like projections also extended from the anterior tip of the mucron. The distinctively large trophozoites of Trichotokara eunicae n. sp. lacked an elongated mucron and had a tadpole-like cell shape consisting of a bulbous anterior region and a tapered tail-like posterior region. The cell surface was covered with longitudinal epicytic folds with a density of three to five folds/micron. Small subunit (SSU) rDNA sequences of both species were very divergent and formed a strongly supported clade with the recently described species Trichotokara nothriae and an environmental sequence (AB275074). This phylogenetic context combined with the morphological features of T. eunicae n. sp. required us to amend the description for Trichotokara. The sister clade to the Trichotokara clade consisted of environmental sequences and Lecudina polymorpha, which also possesses densely packed epicyctic folds (35 folds/micron) and a prominently elongated mucron. This improved morphological and molecular phylogenetic context justified the establishment of Paralecudina (ex. Lecudina) polymorpha n. gen. et comb.
  • Kevin C. Wakeman, Brian S. Leander
    JOURNAL OF EUKARYOTIC MICROBIOLOGY 59 (3) 232 - 245 1066-5234 2012/05 [Refereed][Not invited]
     
    Although archigregarines are poorly understood intestinal parasites of marine invertebrates, they are critical for understanding the earliest stages in the evolution of the Apicomplexa. Previous studies suggest that archigregarines are a paraphyletic stem group from which other lineages of gregarines, and possibly all other groups of apicomplexans, evolved. However, substantiating this inference is difficult because molecular phylogenetic data from archigregarines, in particular, and other gregarines, in general, are severely limited. In an attempt to help fill gaps in our knowledge of archigregarine diversity and phylogeny, we set out to discover and characterize novel lineages of archigregarines with high-resolution light and scanning electron microscopy and analyses of small subunit (SSU) rDNA sequences derived from single-cell (SC) PCR techniques. Here, we describe two novel species of Selenidium, namely Selenidium idanthyrsae n. sp. and S. boccardiellae n. sp., and demonstrate the surface morphology and molecular phylogenetic position of the previously reported species S. cf. mesnili. We also describe a novel genus of archigregarine, Veloxidium leptosynaptae n. gen., n. sp., which branches with an environmental sequence and, together, forms the nearest sister lineage to a diverse clade of marine eugregarines (i.e. lecudinids and urosporids). This molecular phylogenetic result is consistent with the hypothesis that archigregarines are deeply paraphyletic within apicomplexans, and suggests that convergent evolution played an important role in shaping the diversity of eugregarine trophozoites.

Conference Activities & Talks

  • A taxonomic study of a novel Haplozoon parasite from Akkeshi, Japan  [Not invited]
    Mana Yamamoto, Kevin Wakeman, 冨岡森理, 堀口健雄
    Japanese Society of Phycology  2018/03
  • Taxonomic study of two new Amphidinium species (Dynophyceae) with predominant non-motile stage  [Not invited]
    Joao Henriques, Kiefer e Silva, Kevin Wakeman, Ryuta Terada, Takeo Horiguchi
    Japanese Society of Phycology  2018/03
  • Diversity of Marine Gregarine Apicomplexans  [Not invited]
    Davis Iritani, Takeo Horiguchi, Kevin Wakeman
    Japanese Society of Phycology  2018/03
  • The Evolutionary (photosynthetic) history of marine apicomplexans and their bizarre relatives  [Invited]
    Kevin Wakeman
    Botanical Society of Japan  2017/11
  • Algal toxins from novel strains of benthic dinoflagellates from Okinawa, Japan  [Invited]
    Kevin Wakeman
    2015/08
  • A brief look at remnant plastids in gregarine apicomplexans  [Invited]
    Kevin Wakeman
    2015/08
  • Transciptomics reveal relic plastids and diverse evolutionary histories among marine gregarine apicomplexans  [Not invited]
    Kevin Wakeman
    2015/05
  • Apicomplexans in our oceans  [Invited]
    Kevin Wakeman
    2014
  • Evolutionary history of two sister species exemplify niche partitioning among gregarine apicomplexans  [Not invited]
    Kevin Wakeman
    International Congress of Protistology  2013/08
  • Marine Apicomplexan Associates of Coral Reefs  [Invited]
    Kevin Wakeman
    2013/01
  • Marine Apicomplexans  [Invited]
    Kevin Wakeman
    2012/10
  • Evolutionary History of Marine Gregarine Apicomplexans  [Not invited]
    Kevin Wakeman
    International Society of Protistology  2012/08
  • Eugregarine and the Archigregarine Concepts  [Not invited]
    Kevin Wakeman
    Joint meeting of the International Society of Evolutionary Protistologsts and the Phycological Society of America  2011

Awards & Honors

  • 2019/04 Hokkaido University Young Researcher Award
     
    受賞者: Kevin Wakeman
  • 2013 University of British Columbia, Zoology Department Zoology Graduate Student Award
     
    受賞者: Kevin Wakeman

Research Grants & Projects

  • Apicomplexans associated with coral reefs in Japan
    Japanese Society for the Promotion of Science (JSPS):Grant in-aid for Young Scientists B
    Date (from‐to) : 2018/04 -2020/03 
    Author : Kevin Wakeman
  • Novel haplosporidian and apicomplexan parasites infecting shellfish fisheries between Japan and New Zealand
    Japanese Society for the Promotion of Science (JSPS):Bilaterial Joint Research
    Date (from‐to) : 2017/04 -2019/03 
    Author : Kevin Wakeman, Jonathan Banks, Stephen Webb

Educational Activities

Teaching Experience

  • Invertebrate ZoologyInvertebrate Zoology Hokkaido Summer Institute (2020)
  • Marine PathologyMarine Pathology Hokkaido Summer Institute (2020)
  • Current Perspectives in ScienceCurrent Perspectives in Science Hokkaido University
  • Biodiversity III: Fundamentals of EcologyBiodiversity III: Fundamentals of Ecology Hokkaido University
  • Biodiversity II: Phycology, Invertebrate Zoology, Botany, and Vertebrate ZoologyBiodiversity II: Phycology, Invertebrate Zoology, Botany, and Vertebrate Zoology Hokkaido University
  • Biodiversity I: Phylogeny and Evolutionary BiologyBiodiversity I: Phylogeny and Evolutionary Biology Hokkaido University
  • Biodiversity Studies I
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : Biodiversity, Speciation, Phylogenetics, Domains of Life, Classification
  • Biodiversity Studies I
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 総合教育部
    キーワード : Biodiversity, Speciation, Phylogenetics, Domains of Life, Classification
  • Biodiversity Studies II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部
  • Biodiversity Studies III
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 理学部


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