Erratum
for
Pace and Manahan, J Exp Biol 209 (1) 158-170.
First published online January 3, 2006
Journal of Experimental Biology 209, 391-392 (2006)
Published by The Company of Biologists 2006
Pace, D. A. and Manahan, D. T. (2006) Fixed metabolic costs for
highly variable rates of protein synthesis in sea urchin embryos and larvae.
J. Exp. Biol. 209,
158-170.
Figs 1 and
7 in both the on-line and print
versions of this paper were published incorrectly.
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Fig. 1. Photomicrographs and primary data sets for protein synthesis and
respiration rate measurements of 13-day-old fed larvae of Lytechinus
pictus. (A) Photomicrograph of 13-day-old unfed and (B) fed larvae. Scale
bars, 200 µm. (C) Linear increase of [14C]alanine incorporation
into the protein pool (TCA-insoluble fraction) of 13-day-old fed larvae of
L. pictus: y=41.4(±2.71)x–68.4
(r2=0.98; P<0.001). Rates of
[14C]alanineincorporation were converted to absolute rates of
protein synthesis (ng protein individual-1 h-1) using
the change in the specific activity of [14C]alanine in the
precursor free amino acid pool (Fig. 1E), the mole-percent of alanine in
protein (7.8%; Table 1) and the mole-percent corrected molecular mass for
amino acids in protein (129.4 g mole-1; Table 1). (D) Chromatogram
of extracted free amino acid pool from 13-day-old larvae of L. pictus
separated using high performance liquid chromotagraphy (HPLC). D, aspartate;
E, glutamate; N, asparagine; S, serine; H, histidine; G, glycine; R, arginine.
Alanine was the [14C]amino acid tracer used to determine rates of
protein synthesis. (E) Specific activity of [14C]alanine in the
free amino acid pool during protein synthesis experiments with 13-day-old
larvae of L. pictus. Specific activity was measured at the specified
sampling intervals by quantifying the moles of total alanine with HPLC (as in
Fig. 1D). [14C]alanine was measured by liquid scintillation
counting of the radioactivity associated with the alanine peak fraction.
Increase of specific activity was described by the linear equation:
y=39.2(±3.85)x+279.9 (r2=0.96;
P<0.001 for ANOVA of regression slope). (F) Respiration rate of
13-day-old fed larvae of L. pictus. Each data point represents a
different respiration chamber. Respiration rate was calculated by determining
the slope of total oxygen consumption in each respiration chamber for the
known number of larvae in that chamber:
y=109.5(±8.4)x+1254 (r2=0.97;
P<0.0001), where the slope of 109.5 has units of pmol
O2 larva-1 h-1.
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Fig. 7. (A) Setting metabolic rate. Percent of total metabolic rate (MR; given as
µJ individual-1 h-1) for different developmental
stages of L. pictus accounted for by protein synthesis and sodium
pump activity (data on Na+/K+-ATPase taken from Leong
and Manahan, 1997). (B) Protein depositional efficiency. Rate of protein
deposition (solid line) calculated from data on total protein content (see
equation in legend of Fig. 2A). Rate of protein synthesis (broken line)
calculated from protein synthesis rate (see equation in legend of Fig. 4).
Rate of protein degradation during development (dotted line) calculated as
difference between rates of synthesis and deposition. All rates were
calculated on a per-larva basis. For 15-day-old larvae, the depositional
efficiency was 21%.
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Panels A and B in Fig. 1
were not labelled. The correct figure is reprinted below.
In Fig. 7B, the broken line
was labelled incorrectly as `Correct measured synthesis=183 ng
day-1' instead of `Measured synthesis=183 ng day-1'. The
correct figure is reprinted below.
In addition, on p. 166,
right column, line 8, `protein dispositional efficiency' should read `protein
depositional efficiency'.
We apologise for these errors and any inconvenience caused.
