1. No category

Lipids of Arthronema africanum strains
from extreme habitats
I. Iliev1, G. Petkov1, S. Furnadzhieva1, R. Andreeva1, J. Lukavský2
2.
1. IPPh “Akad. M. Popov”, BAS, Department “Experimental algology”
Institute of Botany, Academy of Sciences of the Czech Republic, Centre of Phycology.
Blue-green alga Arthronema africanum was found in desert soil near to the sea in Kuwait,
and in high plateaus in Nepal [1]. It was also recently found in desert regions of Spain [2].
Cultivation of Arthronema in diluted pig manure have been object of experiments [3]. The
composition of Arthronema and its physiology have not yet been studied. Only a cytokinin-like
activity of the alga was described and isopentenyladenine was isolated [4].
The aim of this work is to study the growth of Arthronema africanum, its lipid composition
and fatty acid profile, as well as the influence of temperature and light intensity.
Microscopic photos of
Arthronema africanum
2,5
Two strains of scarcely studied Arthronema africanum (Cyanoprokaryota), originating from
two desert habitats, in Kuwait and Kathmandu (Nepal), were investigated. Both possess a good
adaptability and growth in wide ranges of temperature and light intensity. Lethal temperature of the
strain from Kuwait is 50 ± 1 0С and that from Nepal dies at 47 ± 1 0С (Fig.2). At low light intensity,
the content of phycobiliproteins enhance in accordance with their function as additional lightharvesting antenna complex (Fig.5). Higher light intensity leads to higher content of chlorophyll and
carotenoids (Fig. 3,4)
5
4
3
2
1
0
10
15
20
25
30
35
40
45
2
1,5
1
0,5
50
8 000 lx
2 x 8 000 lx
0
0
24
48
72
96
120
10
15
20
25
30
35
40
45
50
168
30
0,8
0,6
0,4
0,2
8 000 lx
2 x 8 000 lx
25
20
15
10
8 000 lx
5
10
15
20
25
30
35
40
45
50
10
15
20
0
Temperature, C
Main lipid constituents were monogalactosyldiacylglycerol (MGDG),
sulphoquinovosyldiacylglycerol (SQDG), phosphatidylglycerol (PG), and they
were studied in detail (Table 1, Fig.6). Fatty acids of MGDG, SQDG, PG and
total lipids were analyzed (Table 2, Fig.7). The change of fatty acid ratio in the
temperature range 16-46 0С was traced: percentage of linolenic acid decreases
from 33 % at 16 0C, to 0.5 % at 46 0C (Table 3, Fig.8). In comparison to other
algae and higher plants, behaviour of A. africanum presents most clearly
expressed physiological response to the change of temperature. Constantly
high percentage of palmitoleic acid contributes to the endurance of the alga at
stress temperature variations.
Table 2. Fatty acids percentages of individual lipids
Of A. africanum at 27 ±1 0C
25
30
35
40
Temperature, C
Fig. 4 Temperature dependence of
carotenoids at two light intensities
Fig. 5 Temperature dependence
of phycobiliproteins at two light
intensities
MGDG
Table 1. Percentage (m.m-1)
of substances in A. africanum
1
2
3
Substances
%
Lipids in dry biomass
8.8 ± 0.9*
Substances in the lipids
Fig.6 TLC of lipids
1. A. africanum
2. Reference substance PG
3. Reference substance SQDG
MGDG
22**
SQDG
16**
PG
7**
18
Total*
MGDG
SQDG
PG
Chlorophyll a
Myristic acid (14:0)
0.2±0.1
0.2
1.5
0.2
Carotenoids
6
Palmitic acid (16:0)
26±4
24.5
24.5
48.8
Total fatty acids
24
Palmitoleic acid (16:1)
27±3
34.1
37.7
9.5
Unsaponifiable
9.6
Fatty acids
0.3±0.1
tr.
tr.
0.8
Oleic acid (18:1)
Stearic acid (18:0)
4±1
2.0
tr.
2.7
Linoleic acid (18:2)
27±3
19.2
9.8
22.0
α-Linolenic acid (18:3)
16±5
19.9
26.5
16.0
* Results are mean value and standard deviation of 3 repetitions.
* Results
are mean value and standard
deviation of 5 repetitions.
** Tentative values
Fig.7 GC of total fatty acids
of A. africanum
Table 3. Influence of temperature on fatty acid profile of A. africanum
16 0C
14:0
16:0
16:1
18:0
18:1
18:2
α-18:3
0.5 ± 0.4
32 ± 3
26 ± 2
0.5 ± 0.2
4±1
4±1
33 ± 3
* Results
20 0C
28 0C
0.5 ± 0.4 0.5 ± 0.4
32 ± 3
35 ± 4
23 ± 3
27 ± 3
0.5 ± 0.2 0.4 ± 0.2
3±1
3±1
9±2
17 ± 3
30 ± 3
17 ± 5
32 0C
35 0C
40 0C
46 0C
0.5 ± 0.4
35 ± 4
36 ± 3
0.7 ± 0.3
5±1
24 ± 3
5±1
0.5 ± 0.4
35 ± 4
22 ± 3
1 ± 0.5
7±2
27 ± 5
3±2
0.5 ± 0.4
40 ± 10
18 ± 2
2±1
9±4
20 ± 5
0.5 ± 0.4
0.5 ± 0.4
40 ± 10
23 ± 2
3±2
20 ± 6
16 ± 10
0.5 ± 0.4
are mean value and standard deviation of 3 repetitions.
Conclusion. Having expressed qualities to withstand to extreme
conditions of deserts and high altitude, Arthronema africanum could be
adopted as prospective photoautotrophic object of biotechnological
studies.
Acknowledgement. Partial support of this work by the project
”Progress in plant investigations for the improvement of sustainability of agriculture
(PISA-INI-14/01.09.2005)” is gratefully acknowledged.
35
30
% of linolenic acid
Fatty acid
45
0
Temperature, C
Fig. 3 Temperature dependence of
chlorophyll a at two light intensities
2 x 8 000 lx
0
0
o
144
35
1
0
Temperature, C
Fig. 2 Influence of temperature at
two light intensities
Time, h
0
Phycobiliproteins,
% of dry w eight
2 x 8 000 lx
C arotenoids, % of dry w eight
Chlorophyll
a,%
total
lipids
Chlorophyll
a, %
of of
dry
weight
Algal density, g.dm-3
8 000 lx
1
0,5
1,2
2,5
6
2
1,5
Dry weight, g.dm-3
Fig. 1 Growth of
Arthronema africanum
25
20
15
10
5
0
10
15
20
25
30
35
40
45
50
Temperatute, 0C
Fig. 8 Influence of temperature on percentage of linolenic acid
References:
1. Komarek J, Lukavsky J. 1988.Arthronema, a new cyanophyte genus
from Afro-Asian deserts. Arch. Hydrobiol. Suppl 80 (Algological
Studies 50-53), 249-267.
2. Asencio A.D., Aboal M. 2003. The presence of Arthronema africanum
(Cyanophyceae / Cyanobacteria, Oscillatoriales) in Almería desert,
SE Spain with implications on its biogeographical distribution. Arch.
Hydrobiol. 108, 7-14.
3. Lepossa A., Ördög V. 2000. Operation of semi-continuous culture of
Arthronema africanum (Cyanobacteria) grown in pig manure. Acta
Agronomica Óváriensis 42(1), 3-11.
4. Stirk W.A., Ördög V., Van Staden J. 1999. Identification of the cytokinin
isopentenyladenine in a strain of Arthronema africanum
(Cyanobacteria). Journal of Phycology 35, 89-92.
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