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Results A B Fig. 22. Comparison of growth, siderophore production and fluorescence of Pss22d and Psg1a. Siderophore production and fluorescence of antagonist Pss22d and pathogen Psg1a were compared during in vitro growth in iron-depleted Pipes medium. The strains were incubated either in 250 ml culture volume in 1 L Erlenmeyer flasks (A) or in 250 ml culture volume in 2 L Erlenmeyer flasks (B). 67
Results reduced in comparison to these prior experiments. As the production of siderophores is known to be tightly regulated, we next analyzed potential regulatory parameters in order to reconstitute the original phenotype. Indeed, siderophore production of Pss22d could be increased by addition of the trace elements Zn 2+ , Cu 2+ , and Ca 2+ . This supplementation did not influence siderophore production in Psg1a, but the CAS activity in Pss22d supernatants was increased to approx. 150 µM DFOM equiv. at OD 600 =1. As the first measurements were performed in the lab of our cooperation partner Dr. Beate Völksch in Jena, chemicals from other commercial suppliers had been used to prepare the medium. Thus a slight variation in medium composition due to variable trace element content has an impact on the quantity of siderophores produced. To investigate this hypothesis, Pipes medium was prepared with chemicals and water supplied by the laboratory in Jena. Doing so, the siderophore activity produced by Pss22d could be slightly increased; under the conditions approximately 200 µM DFOM equiv. an OD 600 =1 were produced by Pss22d. Finally, the influence of culture volume on siderophore production was investigated. Again, the total siderophore activity produced by Psg1a did not change, but the response of Pss22d to different ratios of culture vessel to culture volume became obvious. 250 ml of culture volume were incubated, but this time a 2 L Erlenmeyer flask as used instead of a 1 L-flask (Fig.22B). Under these conditions, the original phenotype could be reconstituted. At the same time, growth of Pss22d was delayed, indicating a possible stress response. The two growth curves gave an interesting insight into regulation of siderophore biosynthesis in Psg1a and Pss22d. Under conditions of lower oxygen supply (250 ml culture in a 1 L-Erlenmeyer flask), Pss22d produced lower amounts of siderophores but relatively high fluorescence. Under high oxygen conditions (250 ml culture in 2 L-Erlenmeyer flask), Pss22d produced approximately the same amount of fluorescence but more than 10 times the siderophore activity. 68
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Siderophore production of Pseudomon
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Acknowledgements This project was s
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Abbreviations Ach achromobactin-lik
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Contents 4.1.2 Pseudomonas syringae
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Contents 5.3 Influence of sideropho
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Introduction 2 Introduction Like hu
Page 13 and 14:
Introduction In contrast to the rhi
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Introduction 2.1.2 Host, pathogen a
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Introduction The relationship betwe
Page 19 and 20:
Introduction developement of resist
Page 21 and 22:
Introduction Fe 2+ + H 2 O 2 → Fe
Page 23 and 24:
Introduction 1997a; May et al., 199
Page 25 and 26: Introduction Pss22d demonstrated a
Page 27 and 28: Introduction 2.4 Aim of this study
Page 29 and 30: Material and Methods Tab. 4. Antibi
Page 31 and 32: Material and Methods Iron-free 5b m
Page 33 and 34: Material and Methods Solution3, car
Page 35 and 36: Material and Methods 3.6 Plasmids T
Page 37 and 38: Material and Methods PCR-Screening
Page 39 and 40: Material and Methods on ice for 10
Page 41 and 42: Material and Methods stained in eth
Page 43 and 44: Material and Methods 4.2.5.3 Conver
Page 45 and 46: Material and Methods 4.2.5.9 Ligati
Page 47 and 48: Material and Methods strains were s
Page 49 and 50: Material and Methods 9.5). For sign
Page 51 and 52: Material and Methods gentle shaking
Page 53 and 54: Material and Methods columns were w
Page 55 and 56: Results 5 Results 5.1 Analysis of s
Page 57 and 58: Results The 13-kb open reading fram
Page 59 and 60: Results If integration is due to a
Page 61 and 62: Results Yersiniabactin is a siderop
Page 63 and 64: Results Next, a large number of tra
Page 65 and 66: Results Nevertheless the site of tr
Page 67 and 68: Results Achr2_KpnI_rev binding site
Page 69 and 70: Results Interestingly the mutant Ps
Page 71 and 72: Results XAD4-purification yielded i
Page 73 and 74: Results After changing the mobile p
Page 75: Results P P A Fig. 21. Isoelectic f
Page 79 and 80: Results A-E represents single inocu
Page 81 and 82: Results Tab. 10. Development of pop
Page 83 and 84: Results Tab. 11. Distribution of th
Page 85 and 86: Discussion bacteria with redundande
Page 87 and 88: Discussion 6.2 Possible regulation
Page 89 and 90: Discussion stationary phase transit
Page 91 and 92: Discussion and bacterium (Loper et
Page 93 and 94: Literature Bultreys, A., Gheysen, I
Page 95 and 96: Literature Galperin, M. Y. (2006).
Page 97 and 98: Literature Mazzola, M. (2002). Mech
Page 99 and 100: Literature Schubert, S., Rakin, A.,
Page 101: Literature Zou, J., Rodriguez-Zas,
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