MARI NE DI NOF L AGE L L AT E S www.harmfulalgae.info - - PowerPoint PPT Presentation

▶
mari ne di nof l age l l at e s
SMART_READER_LITE
LIVE PREVIEW

MARI NE DI NOF L AGE L L AT E S www.harmfulalgae.info - - PowerPoint PPT Presentation

Apr 12, 2023 216 likes •587 views

www.harmfulalgae.info Pa ra lytic she llfish to xin-p ro d uc ing MARI NE DI NOF L AGE L L AT E S www.harmfulalgae.info OUTLINES The organisms (distribution, taxonomy) The biology and ecology (lifehistories, growth

slide-1
SLIDE 1

www.harmfulalgae.info

Pa ra lytic she llfish to xin-p ro d uc ing

MARI NE DI NOF L AGE L L AT E S

slide-2
SLIDE 2

www.harmfulalgae.info

OUTLINES

  • The organisms (distribution, taxonomy)
  • The biology and ecology (life‐histories, growth

physiology, bloom dynamics, inter‐ relationships to other organisms – bacteria, zooplankton, parasites)

slide-3
SLIDE 3

www.harmfulalgae.info

The causative organisms of paralytic shellfish poisoning

What we kno w abo ut

slide-4
SLIDE 4

www.harmfulalgae.info

Zonneveld et al. (2013) Review of Palaeobotany and Palynology Usup et al. (2012) Harmful Algae

Pyrodinium bahamense

Glo bal distributio n…

slide-5
SLIDE 5

www.harmfulalgae.info

Sources: Alexandrium Matsuoka et al., 1997 Yoshida et al., 2000 Usup et al., 2002 Bajarias et al., 2003 Nguyen et al., 2004 Lim et al., 2004 Lim et al., 2005 Pyrodinium Ting and Wong, 1989 Usup et al., 1989 Furio and Gonzales, 2002 Gymnodinium Fukuyo et al., 1993 Holmes et al., 2002 Mohammand-Nor et al., 2002

Re g io nal distributio n…

Fukuyo et al. (2011)

slide-6
SLIDE 6

www.harmfulalgae.info

T he T axo no my…

Pyrodinium bahamense Gymnodinium catenatum

slide-7
SLIDE 7

www.harmfulalgae.info

T he T axo no my…

Alexandrium tamiyavanichii

  • A. tamiyavanichii

– sym A. cohorticula?

  • A. minutum
  • A. catenella (A. pacificum?)

– Reexamination of specimens from type locality – Thorough molecular evidence

slide-8
SLIDE 8

www.harmfulalgae.info

T he mo le c ular syste matic s

  • Morphological plasticity (genetics,

environment adaptation)

  • Molecular evidence

– Which gene marker is suitable? – How many gene marker is sufficient?

slide-9
SLIDE 9

www.harmfulalgae.info

  • Techniques:

– Specific probes with whole‐cell FISH, – qPCR, – flow cytometry

Kon et al. (2015)

Spe c ie s de te c tio n to o ls

slide-10
SLIDE 10

www.harmfulalgae.info

The Life histories in relation to the bloom dynamics

What we kno w abo ut

slide-11
SLIDE 11

www.harmfulalgae.info

Life‐history stages

Technical Guide to Modern Dinoflagellate Cyst Study (Matsuoka & Fukuyo 2000)

Redrawn from Matsuoka & Fukuyo 2000

slide-12
SLIDE 12

www.harmfulalgae.info

  • Studies on Pyrodinium cyst beds in the Philippines (Azanza

1997; Azanza et al. 1999, 2004), Ambon Bay, Indonesia (Mizushima et al. 2007), Sabah, Malaysia (Furio et al. 2012)

  • Alexandrium cyst studies in Japan (e.g. Natsuike et al. 2013;

Kamiyama et al. 2014)

  • Limited data on the relationship of life‐history stages and the

bloom dynamics in the SEA.

slide-13
SLIDE 13

www.harmfulalgae.info

slide-14
SLIDE 14

www.harmfulalgae.info

Alexandrium (cells L‐1)

3 × 107 4 × 106 1 × 106 1 × 105 1 × 107

Law et al. (in prep)

Surve y re sults fro m the 2015 blo o m e ve nt

slide-15
SLIDE 15

www.harmfulalgae.info

Nutrie nt influe nc e

T e trase lmis Diato m

blo o m was asso c iate d with so me what lo we r N/ P

slide-16
SLIDE 16

www.harmfulalgae.info

Charac te rizing the phe no me no lo g y o f blo o m e ve nt

  • A flow cytometry approach
  • To track the different life history stages and

processes affecting bloom initiation and termination.

slide-17
SLIDE 17

www.harmfulalgae.info

Diagram adapted from Brosnahan et al. (2013)

Flow cytometry: measuring the DNA content of bloom populations

‐ To discern the life cycle stages of the algae at cellular level Quantized pattern

slide-18
SLIDE 18

www.harmfulalgae.info

1C 2C 4C 1C 2C 4C 1C 2C 4C

Nuclei‐ Particles having SG‐associated fluorescence

slide-19
SLIDE 19

www.harmfulalgae.info

1C 2C 4C

Relative frequency distribution plots of the field samples recorded in the first bloom

slide-20
SLIDE 20

www.harmfulalgae.info

What c ause game te e xpre ssio n and plano zygo te fo rmatio n?

Salinity dro ppe d T e mpe rature de c re ase d

slide-21
SLIDE 21

www.harmfulalgae.info

Samples containing 4C cells were likely to reach high abundances at elevated temperatures and low PO4 concentrations.

Canonical Correspondence Analysis

slide-22
SLIDE 22

www.harmfulalgae.info

S1 S2 S4 S6 1C 4C On Aug 31 2015 (whe n blo o m starte d)

slide-23
SLIDE 23

www.harmfulalgae.info

S1 S2 S4 S6

  • n Se pt 27 2015

T he blo o m was sustaine d by T he flux o f ne wly-fo rme d ve g e tative c e lls.

slide-24
SLIDE 24

www.harmfulalgae.info

Lau et al. (in prep)

slide-25
SLIDE 25

www.harmfulalgae.info

Liow et al. (in prep)

Se xual pro c e sse s and L ife -histo ry stag e s

L abo rato ry se tup

slide-26
SLIDE 26

www.harmfulalgae.info

Game te e xpre ssio n and plano zygo te fo rmatio n

slide-27
SLIDE 27

www.harmfulalgae.info

GROWTH PHYSIOLOGY

slide-28
SLIDE 28

www.harmfulalgae.info

Growth physiology

  • Pyrodinium bahamense (Usup et al. 1994;

Gedaria et al. 2007; reviewed in Usup et al. 2012)

  • Alexandrium spp. (e.g. Ogata et al. 1999, 2001;

Wang et al. 2008 etc.)

slide-29
SLIDE 29

www.harmfulalgae.info

20 40 60 80 100 120 140 0.0 0.1 0.2 0.3 0.4 0.5 a

r2 = 1.00 r2 = 0.99

20 40 60 80 100 120 140 0.0 0.1 0.2 0.3 0.4 0.5 20o C 25o C

b

r2 = 0.98 r2 = 0.90

Growth rate,  (day-1) Irradiance (mol photonsm-2s-1)

  • A. tamiyavanichii
  • A. minutum

Light-adapted Shade-adapted

Radiating type Peripheral type

Growth physiology Alexandrium spp.

slide-30
SLIDE 30

www.harmfulalgae.info

“Omic” Approaches

Achieving the capabilities by Genetic and Metabolic Engineering

  • Characterize the physiological responses via “omic”

technologies (Transcriptomic, Genomic, metabolomic, etc.)

slide-31
SLIDE 31

www.harmfulalgae.info By investigating the transcriptional responses of the core sxt genes in the saxitoxin biosynthesis…

Clonal batch cultures RNA extraction, cDNA with Superscripts III Amplification and sequencing In silico primer design Relative qPCR: 2‐∆∆C

T method

Toxin analysis

  • Highest toxin cell quota, Qt

was observed in low P cultures.

  • Highest Qtin ammonia‐

growth cultures compared to nitrate.

Cell density increased in highest P: NIP>NAP>NLP (Nitrate), AP1> AP2 (Ammonia)

  • No significant differences were
  • bserved in the mean exponential‐

growth rates among treatments.

  • Cells adjusted their cellular

activities and mechanisms, such that their growth was maintained under various nutrient levels and ratios.

slide-32
SLIDE 32

www.harmfulalgae.info

Regulation of the sxt genes in a tropical Alexandrium minutum strain is responsive to distinct physiological stresses. This cellular response might be advantageous in unfavorable environmental conditions, thus leading to successful bloom formation.

slide-33
SLIDE 33

www.harmfulalgae.info

AmGSIII plays an important role to remove the excess ammonium stress and simultaneously enhance STX production.

Transcriptional and Physiological Responses to Inorganic Nutrition in Alexandrium minutum: Implications for Nutrient Uptakes and Assimilation

AmNrt2, AmAmt1 and AmPiPT1 are high affinity transporters; AmGSIII is a mitochondria enzyme; AmNas is a cytosol enzymes; and AmCPSII is a pyrimidines synthesis related enzyme. Uptake of nitrate is favourable than ammonium in A. minutum; AmAmt1 is supressed at excess NH4

+ , but AmNrt2 and AmNas were highly expressed.

AmCPSII is related to arginine metabolism and increase the toxin production of the cells. Survival strategy for A. minutum under unfavorable environment (P‐stressed) is likely inducing the expression of AmNrt2, AmAmt1, AmNas, AmPiPT1 and AmGSIII.

slide-34
SLIDE 34

www.harmfulalgae.info

C ha lle ng e s G a p s

slide-35
SLIDE 35

www.harmfulalgae.info

THANK YOU

Acknowledgements

Travel awards by JFIT, WESTPAC Grants by MoHE, MOSTI, UM JSPS COMSEA Oversea Research Associates Graduate students