Determination and characterization of genes involved in toxic mechanisms of the prymnesiophyte Prymnesium parvum [Elektronische Ressource] / vorgelegt von Michael Frederick Freitag

Mfreitag

Description

Determination and characterization of genes involved in toxic mechanisms of the prymnesiophyte Prymnesium parvum Michael Frederick Freitag Dissertation zur Erlangung des Akademischen Grades eines Doktors der Naturwissenschaften - Dr. rer. Nat.- im Fachbereich 2 (Biologie & Chemie) der Universität Bremen vorgelegt von Michael Frederick Freitag 2011 1. Gutachter: Prof. Dr. Allan Cembella Alfred-Wegener-Institut für Polar- und Meeresforschung Bremerhaven u. Universität Bremen 2. Gutachter: Prof. Dr. Kai Bischof Leibniz-Zentrum für Marine Tropenökologie Universität Bremen III Contents Table of Contents I Acknowledgements ................................................................................................................................................. VI II Summary ................................................................................................................................................................... VII III Zusammenfassung ................................................................................................................................................ IX IV Abbreviations ................................................................................................................................

Sujets

• Biologie

Informations

• Publié par: universitat_bremen
• Publié le: 01 janvier 2011
• Nombre de lectures: 28
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Determination and characterization of genes
involved in toxic mechanisms of the
prymnesiophyte Prymnesium parvum
Michael Frederick Freitag
n atiortDisse

zur Erlangung des Akademischen Grades eines

Doktors der Naturwissenschaften

t.-r. Na Dr. re-

im Fachbereich 2 (Biologie & Chemie) der Universität Bremen

vorgelegt von

Michael Frederick Freitag

1201

1.

Guchtar: Ptero. Dr. Alfln Ceamebll aAlfred-Wegener-Institut für Polar- und Meeresforschung

Bremerhaven u. Universität Bremen

2.

Guchtar: Ptero. Dr. Kfi Basihco fLeibniz-Zentrum für Marine Tropenökologie

Universität Bremen

III

Contents

ntentsle of CoTab I Acknowledgements ................................................................................................................................................. VI
II Summary ................................................................................................................................................................... VII
III Zusammenfassung ................................................................................................................................................ IX
IV Abbreviations .......................................................................................................................................................... XI
1. General introduction .............................................................................................................................................. 1
1.1 Harmful algal blooms ...................................................................................................................................... 1

1.2 Prymnesium parvum ........................................................................................................................................ 3

1.2.1 Phylogeny .................................................................................................................................................... 5

1.2.2 Morphology ................................................................................................................................................. 7

1.2.3 Life cycle (proposed) .............................................................................................................................. 8

1.2.4 Toxicity.......................................................................................................................................................... 9

1.3 Allelopathic role of compounds produced ........................................................................................ 15

1.4 Prymnesiophytes: nutrient physiology ............................................................................................... 17

1.5 Functional genomics: upcoming field in harmful algal research ............................................ 18

1.6 Aim of thesis ..................................................................................................................................................... 19

1.7 Outline of thesis .............................................................................................................................................. 19

2. Publications ............................................................................................................................................................. 23
2.1 Publication 1: Induced toxicity and polyketide synthase gene expression following
physiological shock in the toxigenic Prymnesium parvum ......................................................... 25

2.1.1 Abstract ...................................................................................................................................................... 25

2.1.2 Introduction ............................................................................................................................................. 26

2.1.3 Materials and methods ....................................................................................................................... 29

IV

Contents

2.1.4 Results ........................................................................................................................................................ 42

2.1.5 Discussion ................................................................................................................................................. 42

2.1.6 Conclusions .............................................................................................................................................. 52

2.2 Publication 2: Differential responses of the prymnesiophyte Prymnesium parvum
following interactions with planktonic species ............................................................................... 54

2.2.1 Abstract ...................................................................................................................................................... 54

2.2.2 Introduction ............................................................................................................................................. 56

2.2.3 Materials and methods ....................................................................................................................... 59

2.2.4 Results ........................................................................................................................................................ 67

2.2.5 Discussion ................................................................................................................................................. 76

2.2.6 Conclusions .............................................................................................................................................. 83

2.3 Publication 3: influence of phosphorous limitation and salinity on toxicity and gene
expression in the icthyotoxic Prymnesium parvum (Haptophyceae) .................................... 85

2.3.1 Abstract ...................................................................................................................................................... 85

2.3.2 Introduction ............................................................................................................................................. 86

2.3.3 Materials and methods ....................................................................................................................... 90

2.3.4 Results ..................................................................................................................................................... 100

2.3.5 Discussion .............................................................................................................................................. 106

3. Synthesis ................................................................................................................................................................ 112
3.1 Molecular advances in harmful algal research ............................................................................. 113

3.2 Evolutionary significance of interspecific interactions between P. parvum and
coexisting phytoplankton species ....................................................................................................... 114

3.3 Possible role of polyketide synthases (PKS) in toxic processes originating from P.
parvum .............................................................................................................................................................. 116

3.4 Phosphorous limitation and low salinity as triggers of a toxigenic response ............... 118

4. References ............................................................................................................................................................. 122

V

I. Acknowledgements

Acknowledgements

Albert Einstein once remarked: ‘If we knew what we were doing, it wouldn’t be

research, would it?’ As an awkward Master student beginning my thesis in 2007, this was

much the feeling at that point in time. Fortunately, since then I have grown intellectually,

despite the nature of scientific research not having changed! I would like to thank first and

foremost my supervisors Professor Dr. Allan Cembella and Dr. Uwe John for their support

and helpful discussions, not limited to science but sometimes related to general hurdles in

life in general. Thanks as well to the entire AG Cembella research group: Annegret,

Wolfgang, Bernd, Urban, Sylke, Jan, Philip, Nina, Ines, Haiyan, Karina, Karsten and Aboli for

always keeping me in line.

To my family, Mom, Dad, Matt, Marcus, Chris and Max, thank you for your patience and

understanding, as well as support, without which I would never have had the motivation to

continue my career in natural scientific research. Especially thank you Rack for your

incredible support without which I wo