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Ace Lake, I Om, September replicates showed 0.88 similarity, and the Pendant Lake 4m September replicates showed 0.87 similarity. Therefore any similarity value equal or higher than this would have been considered to be an identical community. For example, during September, Pendant Lake Om, 2m and 4m showed between 0.8 and 0.87 similarities suggesting that these communities were extremely similar to identical, which in turn indicated that there was significant mixing in this part of the water column, possible caused by saline convection current induced by ice cover melt. Pendant Lake showed a similar pattern to Ace Lake, in that spatial similarity was higher between the depths during September than November. The exception to this was between 8m and 10m which during September showed a similarity of 0.46 indicating a significantly different community. In November the similarity between these two depths was 0.73, indicating a possible converging of the different communities at this depth. Temporal variation was significant at Om and 8m, but considerably less variable at 4m and 10m. This suggests that the community at Om and 8m changed considerably compared to 4m and l Om possibly caused by changing salinity due to ice melt and an increase in light levels at the surface. The dendrogram of relatedness for all the community profiles (Fig. 6.5b) indicates two distinct taxonomic groupings separated by a similarity level of 0.31. The first grouping (encircled in red) relates to the community profiles of the hypersaline lakes, Triple Lake, Deep Lake and Club Lake. The second grouping (encircled in green) relates to the community profiles of the brackish lakes, Ace Lake and Pendant Lake. This demonstrates a clear differentiation between the communities adapted to the extremely hypersaline environment and those which have moderate saline tolerance. Salinity is not the only variable between these two lake types, the general physicochemical properties vary significantly between the brackish and hypersaline lakes (refer to Chapter 3). The similarity values for Om and 2m in Triple Lake (Fig 6.5b) were calculated based on the community fingerprints being identical between September and November (data not shown). Therefore, only one of each was used for the community DGGE assessment because it was considered important to perform the DGGE analysis for all lake samples at the same time and there were only 15 viable wells on the DGGE gels. The spatial variation for each date showed a similar profile with depth. The similarity 172
etween Om and 2m was obviously the same during September and November at 0.7. which was probably caused by mixing due to saline convection cells caused by the melting of the ice cover. Between 2m and 4m the similarity varied from 0.5 in September to 0.8 in November, which suggested that the bacterial community in the top four meters was showing greater mixing during November, possible due to more ice-melt. The similarity between 4m and 8m was low in both September and November, indicating a substantially different bacterial population at the bottom of the lake compared with the water column, possibly caused by the interaction with the bacterial population in the sediment. There was high temporal variation for 4m and 8m suggesting that at these depths the population was undergoing significant change between September and November, possibly caused by increases in temperature and light levels. The spatial fluctuation in the community composition of Deep Lake and Club Lake could not be recorded because there was no ice cover on these lakes throughout the year and therefore depth sampling could not be performed. However the temporal fluctuation at Om in Deep Lake between September and November was 0.46 indicating that there was significant change in community between these two dates, possibly caused by influx of bacterial species via melt streams during November, 2000. This is substantiated by an increase in the number of bands detected in the Deep Lake community in November compared with September (Fig. 6.4d). There was no temporal fluctuation in the community in Club Lake. 6.3 - Discussion 6.3.1 - Detection of AFP active isolates in community profiles. Only five out of fourteen AFP active isolates analysed using DGGE were shown to be present in the DGGE community profiles of the lakes of the Vestfold Hills (Figs 6.3a & b). Only one of the five (isolate 213) was represented by particularly intense bands within the profile, which is commonly associated with abundance of template. Template abundance is believed to be proportional to the abundance of a particular species within the original community (Muyzer et al., 1993). Based on this assumption. that band intensity equates with abundance, the majority the AFP active strains 'V ere not abundant within the communities in which they were identified. Isolate 213 was the only 173
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COLD ADAPTATION STRATEGIES AND DIVE
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, 71 "If you march your Winter Jour
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1.6.3. Molecular typing techniques
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3.2.1.2.3. DOC and chlorophyll a ..
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5.3.2.5. The Sphingomonas group, is
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LIST OF FIGURES Figure I. I. Diagra
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Figure 3.17a Mean bacterial abundan
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LIST OF TABLES Table 1.1. Types of
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List of Abbreviations AFP AFGP AFLP
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ACKNOWLEDGEMENTS This study was fun
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Chapter 1: INTRODUCTION 1.1 - Tempe
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1999 ; Hand & Burton, 1981) or iden
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Cold adaptation is dependant on the
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not at 25°C is a function of the a
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The most prolific literature on col
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process known as thermal hysteresis
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dominant, role in the ice-growth in
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explanation for this diversity is t
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1.5.3.5 - Membrane bound solute tra
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een well established (Russell & Nic
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& Bowman, 2001; Labrenz & Hirsch, 2
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The reaction mix contains both deox
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gene mixtures and hence can be used
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displaying a high number of common
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AACGTCGAAA AACCTCGAAA (Organism A)
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particular set of environmental par
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Lake Maximum Depth (m) Approximate
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Larsemann Hills __ rp3rtrnent of th
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Sampling trips took two days during
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Sigma, Sigma-Aldrich Company Ltd.,
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oxidized and the sample then conver
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sample. An appropriate volume was l
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min to ensure complete extension of
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Figure 2.3 - Lane delineation image
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Figure 2.6b - Molecular weights are
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RNA 41F (5'-GCT CAG ATT GAA CGC TGG
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I min. The spin column was removed
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compiled using Seqman and any erron
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ecorded and related to the level of
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information regarding the cold adap
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50ppt to 186ppt. Thirteen were sali
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M N N 't M M \p \p 00 kf) M kf) bA
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as would normally be expected, as b
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1444 6ý L CC vý O Q O O NO u 'c z
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5 - 250 3 245 240 G (, -3 235 a 0-
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3.2.2.2.5 - Dissolved organic carbo
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d 14 12 10 14 12 7 10 8 6 4 2 0 00/
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SRP ('g L- 05 10 15 20 2 3 Depth4 5
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3.2.2.3 - Biological characteristic
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a 0 Bacterial Abundance (x 106 ml-1
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3.3 - Discussion 3.3.1 - Summer sam
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to high surface water temperatures
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chemocline (Rankin et al., 1999). M
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a 250 200 150 100 50 70 60 50 40 ý
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The temperature (Fig 3.2a) through
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et al., 1999). No melt out was obse
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increase in ammonium is probably du
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10 7 9 6 8 E ö 7 5 Co u c m c 40 w
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main pigments were chlorophylls a a
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Inorganic nitrogen (NO2, NO3 and NH
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744 -- 7 644 6 19 ü SE 400-- 4 2s
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salinity decreased from July to Sep
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a Bacterial abundance (x 106 1.1) 0
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8 ö a N Ö oý L _> Q O O 4 0 rn O
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undoubtedly true of Club Lake. The
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suggested that input of bacteria an
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Pendant Lake is an unstratified, sa
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non-AFP active peptides from inhibi
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. ter rý :. 'ý Figure 4.2 -Fryka
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-ý- ---- ,. r. __-_-. ___. r. ýý
Page 141 and 142: 4.2 - Results 4.2.1 - Sampling and
Page 143 and 144: SPLAT score. It has been shown that
Page 145 and 146: 3'E t ý _d M! .PJ r rn 15 3.5 4 3
Page 147 and 148: 4.3 - Discussion Of the 866 bacteri
Page 149 and 150: arisen in very few species due to c
Page 151 and 152: Chapter 5: BACTERIAL MOLECULAR TYPI
Page 153 and 154: Fig 5.1 - Photographs of ARDRA gel
Page 155 and 156: Coefficient: Dice Algorithm: lPGMAA
Page 157 and 158: The closest published relative for
Page 159 and 160: identification was made based on 15
Page 161 and 162: Isolate number Closest phylogenetic
Page 163 and 164: e included due to its small sequenc
Page 165 and 166: 5.3.2 - Identification of the AFP a
Page 167 and 168: explains the fluctuation in related
Page 169 and 170: contamination was lower as the PCR
Page 171 and 172: seen to a certain extent in the ARD
Page 173 and 174: American Type Culture Collection (A
Page 175 and 176: Phylogenetic cluster alignment of t
Page 177 and 178: et al., 1994) and the Antarctic SIM
Page 179 and 180: Chapter 6: BACTERIAL COMMUNITY ANAL
Page 181 and 182: 6.2.1 - Detection of AFP active iso
Page 183 and 184: using the same PCR protocol as orig
Page 185 and 186: Figure 6.1 - Denaturing gradient ge
Page 187 and 188: 6.2.2 - Temporal and spatial variat
Page 189 and 190: Figure 6.4c - Gel I image showing b
Page 191: Coefficient: Dice Algorithm: UPGMA
Page 195 and 196: All PCR-based rRNA molecular techni
Page 197 and 198: 6.3.2.3 - Cellular lysis and DNA pu
Page 199 and 200: hybrids should be equal. However, S
Page 201 and 202: contain contaminants. If the profil
Page 203 and 204: (Section 6.3.2.4.3 ) could not be r
Page 205 and 206: most dominant species in the commun
Page 207 and 208: study was characterised as M protea
Page 209 and 210: 11 species) showed AFP activity. Th
Page 211 and 212: that AFP activity could have evolve
Page 213 and 214: 7.2 - Future Work The 19 AFP active
Page 215 and 216: REFERENCES ABYZOV, S. S. (1993). Mi
Page 217 and 218: BELL, E. M. and LAYBOURN-PARRY, J.
Page 219 and 220: Symposium on Environmental Biogeoch
Page 221 and 222: Research. 5,477-493. CLESCERI, L. S
Page 223 and 224: DRICKAMER, K. (1999). C-type lectin
Page 225 and 226: antifreeze proteins from Atlantic s
Page 227 and 228: FRANZMANN, P. D. and DOBSON, S. J.
Page 229 and 230: GRIFFITH, M., ALA, P., YANG. D. S.
Page 231 and 232: IVANOVA, E. P., KIPRIANOVA, E. A.,
Page 233 and 234: Antarctic Ecosystems. G. A. Llano (
Page 235 and 236: Howard-Williams and I. Hawes). Balk
Page 237 and 238: W. (1998). Rep-PCR-mediated genomic
Page 239 and 240: putida strains from Antarctica. Mic
Page 241 and 242: NICHOLS, D., BOWMAN, J., SANDERSON,
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PEARCE, D. A. and BUTLER, H. G. (20
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(1999). Palaeohydrological modellin
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tracers of biogeochemical processes
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R. G. Landes Company, Austin, Texas
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partial 16S rDNA sequencing. Applie
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YABUUCHI, E., WANG, L., ARAKAWA, M.
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APPENDICES Al. Media Tryptic Soya A
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"D C 'O I. .. r .. r 6 rr E , 4mo .
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. + + + I I I I I I + I + + I I I I
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Ö ON N M 1 O - N 'zt "o l'" 00 C N
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1 T 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
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1 1 1 1 I 1 + I I 1 I 1 1 I 1 1 1 I
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1 1 1 1 1 1 1 I I 1 I 1 I 1 1 I T I
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Cl M 'tt tn '. p t- 00 O\ N M O - (
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d' O - (N M 'nt V) \O N. 00 O> N M
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1 1 T 1 1 1 T 1 1 1 1 1 1 1 1 1 1 1
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+ + i i i i i i " i " . + + + + " +
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e O --ý N M t Vn 1,0 [-- 00 O> N M
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FT ce + I I r. to \, O t- 00 O\ N M
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kn 110 r- 00 Oý N M O - N M Itt vn
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, It N M "t N M Iýt N M M M M Oý
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gj a - - - - - - - - - - - - - - -
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