Effect of temperature and food concentration on the relationship between growth and AARS activity in Paracartia grani nauplii
Abstract
The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth.
Full text
E ec o empe a u e and ood concen a ion on he
ela ionship be ween g ow h and AARS ac i i y in
Pa aca ia g ani nauplii
1Ins i u e o Oceanog aphy and Global Change
2Ins i u o Español de Oceanog a ía
Inma He e a1, Lidia Yeb a2and San iago He nández-Léon1
E ec o de la empe a u a y de la concen ación de alimen o en la elación
en e el c ecimien o somá ico y la ac i idad de la enzima aminoacil ARN
sin e asa en nauplios de Pa aca ia g ani
Pa aca ia g ani (Sa s, G.O. 1904)
Typical o coas al a ea
Condi ioned:
Physical ac o s ( empe a u e)
Biological ac o s ( ood)
Aca iidae a e common in coas al and
es ua ine habi a s wo ldwide.
An impo an componen in he die o
a many o plank on species.
OBJECTIVE
The ela ionship be ween di ec g ow h a es and speci ic
AARSsi u ac i i ies o alida e he AARS me hod as g ow h
index o his species unde di e en empe a u es (12-28ºC)
and ood quan i y (0-880 µg C·L-1).
The e ec o empe a u e and ood quan i y on he g ow h o
Pa aca ia g ani (Sa s 1904).
METHODOLOGY
Oxy his ma ina
ICM
Ins i u e o
Ma ine
Sciences
Pa aca ia g ani
12h day: 12h nigh
pho ope iod
Rhodomonas bal ica
/2 medium
24 hou s Eggs we e collec ed and p ese ed in he idge (4ºC)
METHODOLOGY
Expe imen s a di e en empe a u es
12 º C 16 º C 19.8 º C
24 º C 26 º C 28 º C
Eggs addi ion:
(22.000-64.548)
16 hou s
Oxy his ma ina
220-286 μgC·L-1
(~2 nauplii mL-1)
METHODOLOGY
Expe imen s unde di e en ood concen a ions
0µg C·L
-1 11 µg C·L-1 55 µg C·L-1 110 µg C·L-1
220 µg C·L-1 440 µg C·L-1 880 µg C·L-1
(~2 nauplii mL-1)
METHODOLOGY
100 ml nauplii cul u e
Fixed wi h Lugol’s acid (4%)
Measu ed o leng h and abundance
Mul isize Coul e Coun e
Nauplii g ow h expe imen s
Con e ed in ca bon (C) assuming a ca bon/d y
weigh a io o 0.40 (Pos el e al. 2000).
Leng h measu emen and weigh -speci ic g ow h calcula ions
D y weigh (dw) / leng h
Du bin and Du bin (1978)
A.clausi
W = 19.04 L 2.849, = 0.99
W = d y weigh (μg)
L = p osome leng h(mm)
Tempe a u e quo ien (Q10)
R1and R2= G ow h a es
T1and T2= Tempe a u es
P o ein syn hesis
Aminoacids
mRNA
Ribosome
Ribosome eading a RNA chain p io o he syn hesis o a p o ein (Whi esides, 2001).
P o ein
Fig 2. Pa aca ia g ani nauplii. E ec o empe a u e on A) g ow h (d-1), B) spAARSs(nmPPi·mg p o -1·h-1),
C) indi idual AARSs(nmPPi·ind-1·h-1).
RESULTS & DISCUSSION
Tempe a u e (ºC)
10 14 18 22 26 30
Indi idual AARSs
(nmPPi · ind-1 · h-1)
0.000
0.005
0.010
0.015
0.020
0.025
10 14 18 22 26 30
G ow h (d-1)
0.0
0.2
0.4
0.6
0.8
1.0
10 14 18 22 26 30
spAARSs
(nmPPi · mg p o -1 · h-1)
20
40
60
80
100
120
G = -0.188 + 0.038 · T
2 = 0.984, p < 0.001
spAARSs= -42.51 + 5.44 · T
2 = 0.942, p < 0.001
AARSs·ind-1 = -0.010 + 0.001 · T
2 = 0.852, p < 0.001
Q10 2.1
Q10 2.1
Q10 2.4
RESULTS & DISCUSSION
Fig 5. Pa aca ia g ani nauplii. Rela ionship
be ween g ow h a es (d-1) and A) speci ic AARSs
ac i i ies (nmPPi·mg p o -1·h-1), B) indi idual AARSs
(nmPPi·ind-1·h-1) a di e en empe a u es (ºC).
spAARSs (nmPPi·mg p o -1·h-1)
20 40 60 80 100 120
-0.1
0.1
0.3
0.5
0.7
0.9
Indi idual AARSs (nmPPi·ind-1·h-1)
0.000 0.005 0.010 0.015 0.020 0.025
-0.1
0.1
0.3
0.5
0.7
0.9
G ow h (d-1)
A
B
G = 0.25 + 31.65 · AARSs·ind-1
2 = 0.833, p < 0.001
G = 0.13 + 0.007 · spAARSs
2 = 0.945, p < 0.001
Yeb a e al., 2005
Calanus helgolandicus
R2=0.55
Yeb a e al., 2006
Calanus inma chicus
R2= 0.55
RESULTS & DISCUSSION
Days a e ha ching
ln weigh (ng C)
0
µ
g
C·L
-1
012345678
2
3
4
5
6
11
µ
g
C·L
-1
012345678
2
3
4
5
6
55
µ
g
C·L
-1
012345678
2
3
4
5
6
110
µ
g
C·L
-1
012345678
2
3
4
5
6
220
µ
g
C·L
-1
012345678
2
3
4
5
6
440
µ
g
C·L
-1
012345678
2
3
4
5
6
880
µ
g
C·L
-1
012345678
2
3
4
5
6
-0.01 - 0.68 d-1
Fig 3. Pa aca ia g ani nauplii. Ca bon con en (ng C) inc eases unde di e en ood concen a ions.
Food concen a ion (µg C·l-1)
0 200 400 600 800 1000
Indi idual AARSs
(nmPPi · ind-1 · h-1)
0.000
0.002
0.004
0.006
0.008
0 200 400 600 800 1000
G ow h (d-1)
-0.1
0.1
0.3
0.5
0.7
0.9
0 200 400 600 800 1000
spAARSs
(nmPPi · mg p o -1 · h-1)
20
30
40
50
60
70
80
RESULTS & DISCUSSION
Fig 4. Pa aca ia g ani nauplii. E ec o ood concen a ion on A) g ow h (d-1), B) spAARSs(nmPPi·mg p o -
1·h-1), C) indi idual AARSs(nmPPi·ind-1·h-1); open ci cle: alue no included in i (see ex ).
G = 0.65 · (1 – e(–0.013·C))
2 = 0.986, p < 0.001
AARSs·ind-1 = 0.0032 + 0.0004 ln(C)
2= 0.907, p < 0.05
RESULTS & DISCUSSION
Fig 6. Pa aca ia g ani nauplii. Rela ionship
be ween g ow h a es (d-1) and A) speci ic AARSs
ac i i ies (nmPPi·mg p o -1·h-1), B) indi idual
AARSs(nmPPi·ind-1·h-1) unde di e en ood
concen a ions (µg C·L-1); open ci cle: alue no
included in i (see ex ).
spAARSs (nmPPi · mg p o -1 · h-1)
20 30 40 50 60 70
-0.1
0.1
0.3
0.5
0.7
0.9
Indi idual AARSs (nmPPi · ind-1 · h-1)
0.000 0.002 0.004 0.006
-0.1
0.1
0.3
0.5
0.7
0.9
G ow h (d-1)
A
BG = -0.59 + 204.46 · AARSs·ind-1
2 = 0.951, p < 0.001
G = 1.49 - 0.025 · spAARSs
2 = 0.958, p < 0.0001
RESULTS & DISCUSSION
Fig 7. Pa aca ia g ani nauplii. A) Rela ionship be ween speci ic AARSsac i i ies (nmPPi·mg p o -1·h-1)and
indi idual biomass (µg p o eins · ind-1); B) Rela ionships be ween daily g ow h a es (d-1)andspeci ic
AARSsac i i ies (nmPPi·mg p o -1·h-1) unde di e en ood concen a ions.
20 30 40 50 60 70 80 90
spAARS
s
(nmPPi · mg p o
-1
· h
-1
)
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Daily g ow h a e
s a a ion le el
in e media e le el
sa u a ion le el
0.00 0.05 0.10 0.15 0.20 0.25 0.30
µg p o eins·ind
-1
0
10
20
30
40
50
60
70
80
90
spAARSs (nmPPi·mg p o -1·h-1)
spAARSs= 64.3 – 165.0 · ind biomass
2 = 0.490, p < 0.0001
CONCLUSIONS
G ow h and p o ein syn hesis a es o Pa aca ia g ani nauplii depended on empe a u e
and ood concen a ion.
AARS ac i i y is alid as index o soma ic g ow h o P. g ani nauplii when g ow h is no
limi ed by ood a ailabili y.
The esul s p esen ed he e add o p e ious s udies showing ha he AARSsac i i y is a
use ul ool o es ima ing soma ic g ow h in copepods.
ACKNOWLEDGMENTS
Zooplank on Ecology G oup a he Ins i u e o Ma ine
Sciences (ICM, Ba celona, Spain)
Oi hona p ojec (CTM2007-60052) and Luci e p ojec (CTM2008-03538/MAR)
Thank you o you a en ion!
[email p o ec ed]
Inma He e a