E ec s o ood dep i a ion on he espi a o y
me abolism o Oxy his ma ina
N. Osmaa,*, T. Packa da, M. Gómeza
aBiological Oceanog aphy Labo a o y, Facul ad de Ciencias del Ma , Uni e sidad de las Palmas de G an Cana ia,
Campus Uni e si a io de Ta i a. 35017. Las Palmas de G an Cana ia. Cana y Islands, Spain.
* E–mail: nosma@beca ios.ulpgc.es
INTRODUCTION
The mic ohe e o oph Oxy his ma ina has been used ex ensi ely as a model o ganism o examine
he esponses o he e o ophic lagella es o a a ie y o ac o s. He e, we ocused in he espi a o y
me abolism. Respi a ion is he oxygen consump ion (RO2) ca alyzed by he enzymes o he espi a o y
elec on ans e sys em (ETS). The ETS ans e s he elec ons om he educing equi alen s ha
a e p oduced du ing he oxida ion o o ganic molecules o oxygen (Fig 1). Thus, he RO2 a e o an
o ganism is ela ed o he ood a ailabili y. We ed O. ma ina wi h he c yp ophy a Rhodomonas salina
and we elucida ed he a ia ion o he espi a ion a es in s a a ion.
METHODS & RESULTS
CONCLUSIONS
I) Respi a ion dec eases du ing ood dep i a ion in O. ma ina.
II) ETS ac i i y is cons an du ing ood dep i a ion in O. ma ina.
III) Cell sizes inc eases du ing ood dep i a ion in O. ma ina (cannibalism?).
IV) The R/ETS a io dec eases bo h du ing ood dep i a ion and wi h inc easing cell size in O. ma ina.
Aknowledgemen s
This esea ch, is unded by he Fo ma ion and Pe ec ion o he Resea che Pe sonal P og am o he
Basque Coun y Go e nmen and by he EXZOME p ojec (CTM 2008 –01616/MAR) om he Spanish
Science and Educa ion Minis y.
Re e ences:
Low y, O. H., N. J. Roseb ough, e al. (1951). "P o ein measu emen wi h he olin phenol eagen ." Jou nal o Biological Chemis y 193: 265 - 275.
Packa d, T. T., E. Be dale , e al. (1996). "Oxygen consump ion in he ma ine bac e ium Pseudomonas nau ica p edic ed om ETS ac i i y and bisubs a e enzyme kine ics." Jou nal o Plank on Resea ch 18(10): 1819 –1835.
Figu e 1. S uc u e o he Elec on T ans e Sys em (ETS) coupled wi h
ene gy (ATP) o ma ion.
START SAMPLING!! END SAMPLING!!
0
20
40
60
80
100
120
140
1 2 3 4
RHODOMONAS (Cell numbe x106/l)
0
5
10
15
20
25
30
35
0
20
40
60
80
100
120
140
1 3 5 7 9 11 13 15 17
PROTEIN (mgl-1)
o
CELL NUMBER (x106/l)
RO2o ETS (nmol O2min-1l-1)
I II III IV 1 3 5 7 9 11 13 15 17 TIME(days)
PROTEIN
ETS
CELL NUMBER
RESPIRATION
Figu e 2. (A) Cell numbe decline o Rhodomonas salina in he cul u e due o
he eeding by O. ma ina. The expe imen began when he algae
concen a ion in he cul u e was negligible. (B) Time p o iles o he
measu emen s aken e e y 2 days o p o ein, ETS, espi a ion and cell
numbe o O. ma ina.The p o ein con en and he ETS ac i i y s ayed s able
du ing he en i e expe imen while he espi a ion and he cell numbe
dec eased mo e han 50 %in he i s nine days. Each measu emen
ep esen s he mean o iplica e analyses (n =27).
AB
FEEDING!!
Figu e 3. Time p o iles o : (A) speci ic espi a ion; (B) ETS ac i i y; and (C) p o ein con en pe cell o O. ma ina.
The consump ion o O2pe cell dec eased du ing he expe imen while he ETS ac i i y and p o ein con en
inc eased. Each measu emen ep esen s he mean o iplica e analyses (n=27).
y = -0,0121x + 0,257
R² = 0,7623
0,0
0,1
0,2
0,3
0,4
0246810 12 14 16 18
RO2 (pmol O2h-1cell-1)
TIME (days)
y = 0,0407x + 0,102
R² = 0,7863
0,0
0,2
0,4
0,6
0,8
1,0
0 2 4 6 8 10 12 14 16 18
ETS (pmol O2h-1cell-1)
TIME (days)
y = 0,2105x + 1,2298
R² = 0,8857
0
1
2
3
4
5
6
7
8
0 2 4 6 8 10 12 14 16 18
P o ein (ng cell-1)
TIME (days)
y = -0,589ln(x) + 1,7285
R² = 0,9214
0
0,5
1
1,5
2
0246810 12 14 16 18
R/ETS
TIME (Days)
y = -1,194ln(x) + 1,8581
R² = 0,8795
0
0,5
1
1,5
2
1 2 3 4 5
R/ETS
P o ein/cell (ng/cell)
Figu e 4. (A) Time cou se o he espi a ion / ETS ac i i y a io du ing he expe imen . (B)
Va ia ion o he R/ETS a io wi h cell speci ic p o ein (cell size). The R/ETS a io declined
exponen ially as long as O. ma ina was s a ed (le ). The same beha iou in he a io
occu ed as he cell size inc eased ( igh ). The da a show a Pea son co ela ion coe icien o
-0,902 (n=9, p<0,01).
BA
ACB
Oxy his ma ina.
Rhodomonas salina.
ALGAL
CULTURING
T iplica e cul u es o O. ma ina,a
22.5ºC and low i adiance.
Fil e ed
Samples
ETS ac i i y
Packa d e al (1996)
*adding succina e
P o ein
Low y e al. (1951)
In i o
Samples
Cell numbe
Lugol (4%), Coun ing
chambe
Respi a ion
Oxygen elec odes.
ANALYTICAL
METHODS
MITOCHONDRIA