Characterization and lytic activity of allelochemicals produced by the toxigenic marine dinoflagellate Alexandrium tamarense [Elektronische Ressource] / submitted by Haiyan Ma

Acampo Gmbh

Sujets

• Biologie

Informations

• Publié par: universitat_bremen
• Publié le: 01 janvier 2010
• Nombre de lectures: 19
• Langue: English
• Poids de l'ouvrage: 6 Mo

Extrait

Char act er i zat i on and lyti c act i vi t y of
allelochemi cals pr oduced by the
t oxi geni c mar i ne di noflagellat e
Al exandr i um tamar ense



Dissertation submitted by

H ai yan M a

In partial fulfillment of the requirements for



Doktors der Naturwissenschaften ( Dr. rer. Nat.)


In the Faculty of Biology and Chemistry (Fachbereich 2)
University Bremen
Germany




Bremen, Oct 2010





















TABL E OF CONTENTS

I. AKNOWLEDGEMENTS........................................................................................................ v
II. SUMMARY..............................…………………………..…………………….……......… vii
III. ZUSAMMENFASSUNG.......................................................................................................ix
IV. ABBREVIATIONS…………………….………………………….....................……….... xii

1. GENERAL INTRODUCTION.................................................... ........... .............................. 1
1.1 Harmful Algal Blooms………………...…................……….…………....…..................1
1.2 Alexandrium.......................................................................................................................3
1.2.1 General introduction...................................................................................................3
1.2.2 Ecological impact of Alexandrium blooms............................................... ................6
1.3 Allelopathy…………………………………………………............................................ 6
1.4 Allelopathy among phytoplankton………………………............................................. 7
1.4.1 Phytoplankton groups involved…………………..................................................... 7
1.4.2 Allelochemicals involved in phytoplankton interactions ......................................... 7
1.4.3 Mode of action……………….................................................................................. 9
1.4.4 Factors affecting allelopathy in phytoplankton: Abiotic and biotic factors.............11
1.5 The role of allelopathy in HAB formation and maintenance .................................... 14
1.6 Allelopathy in the genus Alexandrium.......................................................................... 15
1.7 Motivation of the thesis.................................................................................................. 16
1.8 Thesis outline.................................................................................................................. 17

2. PUBLICATIONS................................................................................................................... 19
2.1 Towards characterization of lytic compound(s) produced by
Alexandrium tamarense........................................................................................................ 21
2.1.1 Abstract………………………………………………...………….…................... 21
2.1.2 Introduction…………………………………………………………..................... 21
2.1.3 Materials and Methods...……………………………………………..................... 22
2.1.4 Results and Discussion……………………………………………..….................. 24
2.2 Preliminary characterization of extracellular allelochemicals of the toxic marine
dinoflagellate Alexandrium tamarense using a Rhodomonas salina
bioassay…………………………………..………………………………..…..................... 31
2.2.1 Abstract…………………………...…………………………................................ 31
2.2.2 Introduction…………………………………………...………….……................. 31
2.2.3 Experimental Section……………………………………………….…................. 33
2.2.4 Results………………………………………………………...……...................... 44
2.2.5 Discussion……………………………..……………………………..................... 61
2.2.6 Conclusions ……………………………………………....………........................ 67 2.3 Large non-proteinaceous allelochemicals produced by Alexandrium tamarense –
complementary results for characterization of lytic compounds
from A. tamarense..................................................................................................................69
2.3.1 Abstract……………………...…………………………………….…................... 69
2.3.2 Introduction…………………...………………………………….....…................. 70
2.3.3 Materials and methods ………….....……………………………….…................. 71
2.3.4 Results and discussion…………………...……………………….……..................76
2.3.5 Conclusions ……….. ……………………………...………….………................. 88
2.4 Publication IV: Mode of action of membrane - disruptive lytic
compounds from the marine dinoflagellate Alexandrium
tamarense…………………………………………………………………….….................. 93
2.4.1 Abstract………………………………………………......................…................. 93
2.4.2 Introduction………………………………………………………....…................. 94
2.4.3 Materials and methods ...…………………………………………...…................. 96
2.4.4 Results………..………..………………………………...………….....................103
2.4.5 Discussion……...…………………………………………………….................. 111
2.4.6 Conclusions …...……………………………………………….…….................. 116

3. SYNTHESIS......................................................................................................................... 119
3.1 Allelopathic interactions related to different growth phases and
binding affinity ……………………………………………………………...................... 119
3.2 Allelochemicals of A. tamarense: largest known non-biopolymers produced by
marine phytoplankton……………………....................................................................... 122
3.3 Adaptive advantage of chemical characters of lytic compounds for bio-membrane
interactions and dispersion in aqueous medium ……….................................................126
3.4 Mode of action: Target specificity and protective strategies…………................... 129
3.5 Conclusions………………………….…………………………………….................. 132
3.6 Perspectives for future study…………………………….………......….....................133

4. REFERENCES..................................................................................................................... 137 I. ACKNOWLEDGEMENT

Three years ago, I came to Bremerhaven with complicated moods, including anxiety,
excitement, and curiosity. On one hand, Germany was a totally strange place to me, and I was
not familiar with the research topic I was going to do. On the other hand, a new adventure of
both personal and scientific exploration was in front of me. Now, I dare to say that the past three
years has been fulfilled with help of many people, who I came to know after I stepped onto the
land of Germany.
First of all, I would like to thank my beloved and respected supervisor, Prof. Allan
Cembella. Without your permission to accept me as a PhD student in AWI in the first place, I
would not have the chance to have such a precious living and studying experience. Your
kindness, erudition and amiable personality made my life much easier. You always tried to
understand my poor English when we had discussions or when revising my scientific writings.
You sent me to international conferences to broaden my horizons. You just meet the figure I
draw for a professor in my mind.
Bernd, my beloved direct supervisor, you are the one who trained me from a beginner
who never extracted chemicals with organic solvents to an experienced biochemical scientist
who can set up a new chromatographic methods and analyze data alone. Our personalities are
quite matched in that we both finish things fast. I have to say that without your quick response
on experimental results analysis, manuscript revision, etc., I could not be able to finish my PhD
study in time. In personal life, you know my personality as a friend. You always encourage me
to overcome my weaknesses and to perfect myself. You are not only my good scientific guider
but also a good friend!
Urban, you are the one who guided my first experiment in AWI. Your kindness and
patience made my nervous mood easy when I first started to work here. You are a careful and
precise scientist, and often come up with ideas from different angles. My understanding of
science is much more comprehensive with your help.
Annegret and Wolfgang, I would like to thank both of you for your laboratory and
V personal help during my study in AWI.
I want to thank all members of AG Cembella (Karina, Ines, Michael, Nina, Sylke,
Philip, Aboli, Tilman, Sára, Yameng, Uwe and Andrea), who are or were in the same research
group with me. My working life and spare time is much more fruitful with you guys.
I would like to thank all the co-authors of the publications in this thesis, Dr. Ulf
Bickmeyer and Dr. Martin Graeve from AWI; Dr. Alexander Muck, Dr. Natalie Wielsch, and Dr.
Aleš Svatoš from MPI (ICE) Jena. My thesis could not be accomplished without your work.
Thanks to Dieter Janssen and Tim for running GC/MS and analyzing sterol compositions. And I
would also like to thank Ute Marx for teaching me to operate the ultra-centrifuge and Jutta
Juergens for teaching me to operate the French-Press, without which I could not finish the
necessary experiments.
Thanks to DAAD for funding my three year PhD study. And I would like to say special
thanks to the contact person Mrs. Irmg