maenas (intertidal zone) and Segonzacia mesatlantica - Station ...

More documents

Recommendations

Info

The Structural Analysis of Large Noncovalent Oxygen Binding Proteins Current Protein and Peptide Science, 2008, Vol. 9, No. 2 175 (a) ESI-MS under denaturating conditions 100 15952 15974 49581 49531 49650 49708 49724 (b) ESI-MS under denaturating and reduced conditions 15975 100 15952 16662 AB % 49781.0 % 15891 16018 16034 16981 17031 0 ∫∫ 0 B 100 % 15974 49581 49620 49724 100 % 15930 15891 15975 16035 16662 17031 0 15900 16000 ∫∫ 49500 50000 0 49670 16662 16000 16500 17000 100 15950 49655 100 A % 49528 49696 % 15952 16018 16981 0 15900 16000 ∫∫ 49500 50000 50500 0 15891 16000 16500 17000 Mass (Da) Mass (Da) Fig. (10). MaxEnt-processed spectra of three AmHb structural profiles. MaxEnt-processed spectra of native (a) and reduced (b) AmHb characterizing three different structural profiles (A, B and AB). AB is the combination of A and B. The Mw of each globin subunit and chains characterizing each profile are summarized Table 4. Table 4. Tree Different Structural Profils of AmHb Obtained from ESI-MS Analysis Profils Mass (Da) of Globin Subunits A AB B Monomers (± 2Da) M1–15921 X X M2–15975 X X T1–49528 X X T2–49581 X X T3–49620 X X Trimers (± 4Da) T4–49655 X X T5–49670 X T6–49708 X T7–49724 X X Mass (Da) of globin chains Monomers (± 2Da) M1–15921 X X M2–15975 X X 96
176 Current Protein and Peptide Science, 2008, Vol. 9, No. 2 Bruneaux et al. (Table 4) contd…. Profils A AB B Mass (Da) of Globin Subunits M3–15891 T1 T1 T2 M4–15930 T3 T3 Monomers forming the disulfide bounded trimers (±2Da) M5 – 16 018 T4 T4,6 M6 – 16 035 T5,7 T7 M7 – 16 664 T1,4 T1,3,4,6,7 T2,3,7 M8 – 16 981 T1,4 T1,4,5 M9 – 17 032 T2,3,6,7 T2,3,7 reproduce it. This condition is essential to obtain biologically relevant data and to avoid any experimental degradation or aggregation due to inadequate solvent. It also permits to test the effect of changes in buffer composition on the aggregation state, for example to test the influence of divalent cations on complex stability and to follow dissociation and association mechanisms. Light scattering at one angle is very widely used to follow dissociation and reassociation of multimeric proteins; it was an important method used by Herskovits to investigate the dissociation of gastropods hemocyanins [122, 130]. MS can also be used to investigate differences between experimental conditions. Aggregation states in hydrothermal vent crabs exposed to hypoxia and hyperoxia were monitored by noncovalent ESI-MS [74]. Segonzacia mesatlantica were held at deep-sea pressure under hypoxia or hyperoxia alternatively for 6h periods. ESI-MS analysis detected hexamers, dodecamers and 18-mers in crabs from both conditions. Two overlapping distributions were detected for the dodecamer and 18-mer ion series, revealing the presence of two different forms for each aggregation state. Most interestingly, a difference in the proportion of each dodecamer species was detected between the two conditions (ratio 21:79 after hypoxia and 27:73 after hyperoxia). These experiments were made on hemolymph pooled from 4 crabs and it is still possible that random interindividual variability might exist within the pools, but these results suggest an environmental effect upon dodecamer proportions and in any case demonstrate the possibility to detect precise adjustment in proportion of very close complexes in different experimental conditions. 9.2. Investigating the Role of Phenotypic Plasticity in Response to Environmental Challenge at the Subunit Level As mentioned earlier, crustacean Hc present a very high potential phenotypic plasticity due to (a) the simultaneous existence of several aggregation states made of numerous subunits (mainly hexamer and dodecamer) and (b) the diversity of the subunits types. These two elements allow many potential combinations to be produced at the molecular level, with modulation of oxygen binding properties. Crustaceans can live in a wide variety of habitats: some are terrestrial species (e.g. land crab Birgus latro) and most are aquatic species. They are found from fresh water to sea water, from the intertidal zone to deep-sea hydrothermal vents. The comparative study of physiological mechanisms occurring in the very large range of conditions experienced by the different groups is of great interest. It is also very appealing to study some species of which individuals can support changing conditions. Contrary to the crab Cancer pagurus, which can only survive in non-diluted sea water, Carcinus maenas and Callinectes sapidus can support very diluted sea water in estuary areas and large pO2 range. Deep-sea hydrothermal vent species living in the mixing zone between sea water and hydrothermal fluid are exposed to rapid and unpredictable changes [131]. The diversity of experienced environment suggests the presence of original physiological adaptations. Many mechanisms are at work: ventilatory and circulatory rates compensation, metabolism adjustment [132]. Hemocyanin oxygen affinity can be modified by hemolymph modulators (inorganic and organic ions) [25]. Phenotypic plasticity has been observed in several situations. It is related to ontogeny when different subunits are expressed during successive developmental stages as in the Dungeness crab Cancer magister [133-135], as is observed for some vertebrates which switch from fetal hemoglobin to adult hemoglobin. Environmental changes induce phenotypic changes in the blue crab Callinectes sapidus or the spiny lobster Panulirus elephas: individuals caught from different conditions exhibit different subunits [27, 29]. Genetic differences cannot explain this observation since the subunit expression pattern changes when individuals are transferred to different conditions. It has been proved that these composition changes are related with functional property changes in the case of C. sapidus, P. elephas and P. mauritanicus [26-28]. An environmental influence has also been evidenced in the case of the Hb from the microcrustacean Daphnia magna [136]. Two approaches to comparative phenotypic plasticity are possible. Comparison between different species living in different environments should help to outline long-term adaptations. On the other hand, comparison between individuals of the same species exposed to different conditions should help to detect short-term phenotypic adaptations. Subunits are to be identified precisely to investigate phenotypic plasticity involved in short-term adaptation. As mass spectrometry is a very precise and accurate method for de- 97
Page 1 and 2:
THESE DE DOCTORAT DE L’UNIVERSITE
Page 3:
i Résumé / Abstract Réponse adap
Page 6 and 7:
iv SOMMAIRE 4.2 Objectifs de l’é
Page 8 and 9:
2 CHAPITRE 1. INTRODUCTION Les éco
Page 10 and 11:
4 CHAPITRE 1. INTRODUCTION 1.1 Mili
Page 12 and 13:
6 CHAPITRE 1. INTRODUCTION Les prin
Page 14 and 15:
8 CHAPITRE 1. INTRODUCTION TAB. 1.1
Page 16 and 17:
10 CHAPITRE 1. INTRODUCTION et cycl
Page 18 and 19:
FIG. 1.5 - Localisation des princip
Page 20 and 21:
(a) FIG. 1.6 - Fonctionnement d’u
Page 22 and 23:
16 CHAPITRE 1. INTRODUCTION TAB. 1.
Page 24 and 25:
18 CHAPITRE 1. INTRODUCTION FIG. 1.
Page 26 and 27:
20 CHAPITRE 1. INTRODUCTION Différ
Page 28 and 29:
22 CHAPITRE 1. INTRODUCTION FIG. 1.
Page 30 and 31:
24 CHAPITRE 1. INTRODUCTION le mili
Page 32 and 33:
26 CHAPITRE 1. INTRODUCTION Capacit
Page 34 and 35:
28 CHAPITRE 1. INTRODUCTION TAB. 1.
Page 36 and 37:
30 CHAPITRE 1. INTRODUCTION 700 600
Page 38 and 39:
32 CHAPITRE 1. INTRODUCTION férent
Page 40 and 41:
34 CHAPITRE 1. INTRODUCTION (a) (b)
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
40 CHAPITRE 1. INTRODUCTION 1 P 50
Page 48 and 49:
42 CHAPITRE 1. INTRODUCTION presque
Page 50 and 51:
44 CHAPITRE 1. INTRODUCTION affecte
Page 52 and 53: 46 CHAPITRE 1. INTRODUCTION FIG. 1.
Page 54 and 55: 48 CHAPITRE 1. INTRODUCTION FIG. 1.
Page 56 and 57: 50 CHAPITRE 1. INTRODUCTION fure co
Page 58 and 59: 52 CHAPITRE 1. INTRODUCTION amélio
Page 60 and 61: 54 CHAPITRE 1. INTRODUCTION 1.5 Que
Page 62 and 63: 56 CHAPITRE 2. ESI-MS ET MALLS APPL
Page 78 and 79: The Structural Analysis of Large No
Page 108 and 109: 102 CHAPITRE 2. ESI-MS ET MALLS APP
Page 110 and 111: 104 CHAPITRE 3. STRUCTURE DE L’HC
Page 140 and 141: 134 CHAPITRE 4. PLASTICITÉ PHÉNOT
Page 152 and 153:
146 CHAPITRE 4. PLASTICITÉ PHÉNOT
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Dénaturant Natif
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
172 CHAPITRE 5. ADAPTATIONS RESPIRA
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
216 CHAPITRE 6. CONCLUSION ET PERSP
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 233 and 234:
Annexe A Détermination des masses
Page 235 and 236:
229 10000 h280 .M h) h280−h337 80
Page 237 and 238:
Annexe B Détermination des distrib
Page 239 and 240:
233 Modèle 2 : 2 sous-unités lég
Page 241 and 242:
235 1 0.9 0.8 6 s-u aléatoires 2 s
Page 243 and 244:
Bibliographie Adair, G. S. The hemo
Page 245 and 246:
BIBLIOGRAPHIE 239 Catalina, M. I.,
Page 247 and 248:
BIBLIOGRAPHIE 241 Farmer, C. S., J.
Page 249 and 250:
BIBLIOGRAPHIE 243 Hourdez, S. Adapt
Page 251 and 252:
BIBLIOGRAPHIE 245 Mangum, C. P. Sub
Page 253 and 254:
BIBLIOGRAPHIE 247 Rainer, J., C. P.
Page 255 and 256:
BIBLIOGRAPHIE 249 Svedberg, T. et I
Page 257 and 258:
BIBLIOGRAPHIE 251 Vanin, S., E. Neg
Page 259 and 260:
Liste des figures 1.1 Cycle des mar
Page 261:
LISTE DES FIGURES 255 4.17 Profils
Page 265 and 266:
Table des matières Résumé Sommai
Page 267 and 268:
TABLE DES MATIÈRES 261 4.3.5 Spect
Page 269 and 270:
TABLE DES MATIÈRES 263 Table des m
show all

maenas (intertidal zone) and Segonzacia mesatlantica - Station ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?