[PPT] - Cochlodinium polykrikoides Mitsunori Iwataki Asian Natural PowerPoint Presentation

SLIDE 1

Cochlodinium polykrikoides

Mitsunori Iwataki Asian Natural Environmental Science Center, The University of Tokyo, Japan

SLIDE 2

An unarmored dinoflagellate Cochlodinium polykrikoides has formed red tides responsible for mass mortalities of caged and natural fishes in Japanese and Korean coasts.

Mass mortality of cultured red sea breams, in Imari Bay, west Kyushu in 1999.

A harmful dinoflagellate C. polykrikoides

SLIDE 3

The genus Cochlodinium has been established by Schütt (1894), circumscribing unarmored dinoflagellates possessing the cingulum encircling the cell >1.5 times (Kofoid & Swezy 1921).

C. polykrikoides was described from Puerto Rico

(Margalef 1961) In Japan, morphologically similar species, together with C. polykrikoides, were observed, including

C. convolutum, C. cf. geminatum, C. fulvescens and

Cochlodinium sp. type-Kasasa. .

C. catenatum
C. citron
C. lebourae

Kofoid & Swezy 1921

Cochlodinium polykrikoides

Cochlodinium sp. type-Kasasa

(Yamatogi et al. 2010)

C. convolutum
C. cf. geminatum
C. fulvescens
C. polykrikoides

SLIDE 4

C. achromaticum Lebour 1925
C. adriaticum Schiller 1933
C. angustatum Kofoid et Swezy 1921
C. archimedes (Pouchet) Lemmermann 1899
C. atromaculatum Kofoid et Swezy 1921
C. augustum Kofoid et Swezy 1921
C. brandtii Wulff 1916
C. catenatum Okamura 1916*
C. cavatum Kofoid et Swezy 1921
C. cereum Kofoid et Swezy 1921
C. cnidophorum Biecheler 1939
C. citron Kofoid et Swezy 1921
C. clarissimum Kofoid et Swezy 1921
C. conspiratum Kofoid et Swezy 1921
C. constriclum (Schütt) Lemmermann 1899
C. convolutum Kofoid et Swezy 1921
C. distortum Kofoid et Swezy 1921
C. elongatum Kofoid et Swezy 1921
C. faurei Kofoid et Swezy 1921
C. flavum Kofoid et Swezy 1921
C. geminatum (Schütt) Schütt 1896
C. helikoides Lebour 1925
C. helix (Pouchet) Lemmermann 1899
C. heterolobatum Silva 1967 *
C. lebourae Kofoid et Swezy 1921
C. longum Lohmann 1908
C. miniatum Kofoid et Swezy 1921
C. moniliforme Margalef 1961
C. pellucidum Lohmann 1908
C. pirum (Schütt) Lemmermann 1899
C. polykrikoides Margalef 1961*
C. pulchellum Lebour 1917
C. pupa Lebour 1925
C. radiatum Kofoid et Swezy 1921
C. rosaceum Kofoid et Swezy 1921
C. schuettii Kofoid et Swezy 1921
C. scintillans Kofoid et Swezy 1921
C. strangulatum (Schütt) Schütt 1896 (Type)
C. turbineum Kofoid et Swezy 1921
C. vinctum Kofoid et Swezy 1921
C. virescens Kofoid et Swezy 1921
C. volutum Kofoid et Swezy 1921

More than 40 Cochlodinium species have so far been described. Blue: photosynthetic species, Red: type species

Cochlodinium species

SLIDE 5

C. convolutum
C. cf.geminatum
C. polykrikoides
C. fulvescens

Length

ca. 60-70 µm
ca. 40-60 µm
ca. 30-40 µm
ca. 45-50 µm

Eye spot Absent Absent Dorsal, epicone Dorsal, epicone Cingulum

ca. 1.5 times
ca. 1.5 times
ca. twice
ca. twice

Sulcus Deeper Deeper Shallow, immediately below the cingulum Shallow, intermediate

f the cingulum

Nucleus Rectangular Spherical, median Spherical, anterior Spherical, anterior

Chloroplast

Reticulate Reticulate Rod-like, aligned longitudinally Granulate Others Forming hyaline cyst Cell-chains (2 cells) Cell-chains (16 cells) Cell-chains (4 cells)

Morphological characters of Cochlodinium spp.

SLIDE 6

Cochlodinium polykrikoides Margalef Cochlodinium fulvescens Iwataki, Kawami et Matsuoka

Description of Cochlodinium fulvescens

Iwataki et al. 2007, Phycol. Res.

SLIDE 7

U-shaped apical groove connected with sulcal extension.

Apical groove of Cochlodinium polykrikoides

Iwataki et al. 2010, J. Eukaryot. Microbiol.

SLIDE 8

C. polykrikoides

Apical groove of Cochlodinium fulvescens

C. fulvescens
C. fulvescens

(Iwataki et al. 2010) (Iwataki et al. 2015)

SLIDE 9

（Nagasaki Prefectural Institute of Fisheries

1991-2003）

Cochlodinium growth

Where and how do cells survive at low (≤ 12.5ºC) temperature?

SLIDE 10

Akashiwo sanguinea AF260396 Karenia mikimotoi AY355460 Gymnodinium catenatum AF200672 Cochlodinium polykrikoides Korea (6 isolates) Cochlodinium polykrikoides Japan (8 isolates) Cochlodinium polykrikoides Hong Kong Cochlodinium polykrikoides Manila Bay, Philippines Cochlodinium polykrikoides Omura Bay, Japan Cochlodinium polykrikoides Sabah, Malaysia (2 isolates) Cochlodinium polykrikoides New York, USA Cochlodinium polykrikoides Massachusetts, USA Cochlodinium polykrikoides Puerto Rico Cochlodinium polykrikoides Mexico Cochlodinium fulvescens Japan Cochlodinium fulvescens California, USA Cochlodinium fulvescens British Columbia, Canada

0.05 substitutions/site

Philippines East Asian American/Malaysian

NJ MP/ML 100 100/100 72 100/99 97 100/100 93 100/100 95 100/99 96 97/83 89 100/98 100 100/ 100

71/71
C. fulvescens

Gamma weighted ML tree based on partial LSU rDNA (D1-D6 region) Substitution model: TrN+G (Tamura & Nei 1993), Shape parameter: 0.5580

Phylogenetic relationship in Cochlodinium spp.

(Iwataki et al. 2008)

SLIDE 11

Ribotypes

Gamma weighted ML tree based on partial LSU rDNA (D1-D6 region) Substitution model: TrN+G (Tamura & Nei 1993), Shape parameter: 0.4298

Takahashi unpubl.

SLIDE 12

qPCR

Park et al. 2014, Harmful Algae

Philippines ribotype did not occur as large bloom, nor did in the same bloom of East Asian ribotype

LM qPCR philippines

SLIDE 13

Cochlodinium sp. type-Kasasa kills fishes

Yamatogi et al. 2010, Jpn. J. Phycol.

SLIDE 14

Similar resting cyst to what was identified formerly as C. polykrikoides Germinated motile cell was similar to

C. polykrikoides

Fukuyo 1982 Matsuoka & Fukuyo 2000

Cyst morphology of Cochlodinium cf. geminatum

SLIDE 15

Cyst morphology of Cochlodinium polykrikoides American ribotype

Tang et Gobler 2012, Harmful Algae

SLIDE 16

FISH assay of cysts in Shinnecock Bay (American ribotype)

Hattenrath-Lehmann et al. 2016, Appl. Environ. Microbiol.

SLIDE 17

Cyst morphology of Cochlodinium polykrikoides East Asian ribotype

Li et al. 2015, J. Phycol.

SLIDE 18

C. polykrikoides in Lampung Bay

infected with Parvilucifera

Takahashi unpubl. Lepelletier et al. 2014 Parvilucifera rostrata

SLIDE 19

Cochlodinium polykrikoides Cochlodinium fulvescens

Distribution of C. polykrikoides population

SLIDE 20

Cochlodinium polykrikoides Cochlodinium fulvescens

Japan, Korea Other sequences

C. polykrikoides

Manila Bay, Philippines Lampung Bay, Indonesia

North America

Japan and Korea Hong Kong

? ?

Sabah, Malaysia

Distribution of C. polykrikoides population

SLIDE 21

Cochlodinium polykrikoides Cochlodinium fulvescens not analyzed yet

Global distribution of Cochlodinium

SLIDE 22

Occurrence of C. polykrikoides in the Arabian Gulf

SLIDE 23

Cochlodinium bloom in Lampung Bay, 2012

SLIDE 24

Summary

C. polykrikoides and C. fulvescens. They could be distinguished by

cell size, position of the sulcus, and shape of chloroplast and apical groove.

In C. polykrikoides, ribotypes (East Asian, Philippines, American and

Mediterranean) can be differentiated.

Resting cysts were reported from American and East Asian ribotypes.

Their morphology differ from each other in the presence/absence of

rnamentation and accumulation body. FISH assay allowed to detect

more than 140 cysts cm-3 in the sediment sample.

Majority of C. polykrikoides red tides occurred in Japanese, Korean

and Hong Kong coasts are derived from the same population; it could be distinguished from other populations distributed in Southeast Asia.

The C. polykrikoides clade from Sabah, Malaysia and Lampung Bay,

Indonesia is related to that from North and Central America.

SLIDE 25

Future study

Morphological differences among different ribotypes
Other ribotype? Cochlodinium sp. type Kasasa, also related to fish

killing.

Morphology of resting cyst in each ribotype
It is unclear what factor corresponds to the morphological

difference observed from East Asian and American

Harmful effects of each ribotype

Fish kill was not reported by red tide of Philippines ribotype.

Environment of Cochlodinium easy to settle.