First published online February 20, 2004
Journal of Experimental Biology 207, 1127-1135 (2004)
Published by The Company of Biologists 2004
doi: 10.1242/jeb.00859
The effect of molluscan glue proteins on gel mechanics
J. M. Pawlicki1,
L. B. Pease1,
C. M. Pierce1,
T. P. Startz1,
Y. Zhang2 and
A. M. Smith1,*
1 Department of Biology, Ithaca College, Ithaca, New York 14850,
USA
2 Department of Materials Science and Engineering, Cornell University,
Ithaca, New York 14850, USA

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Fig. 1. Elution profile of L. irrorata adhesive mucus on a sephacryl S-400
column. The protein peak corresponds to a molecular mass of roughly
10100 kDa and the carbohydrate peak corresponds to roughly 1000 kDa,
based on calibration of the column with BSA (66 kDa), ferritin (440 kDa) and
blue dextran (2000 kDa).
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Fig. 2. Examples of the qualitative effect of glue proteins from L.
irrorata on gel mechanics. Samples were mixed in a microcentrifuge tube
and poured or scooped out. Samples with glue proteins (0.51 mg
ml1) are on the right (Adhesive). Samples with the same
concentration of BSA are on the left (Control). (A) 0.6% agar, (B) 2%
polygalacturonic acid.
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Fig. 3. Identification of glue proteins from slug and land snail glue. (A) SDS-PAGE
comparison between equal amounts of trail and adhesive mucus (glue) from the
slug A. subfuscus. Arrowheads mark the 15 and 61 kDa proteins that
are significantly more common in the adhesive mucus. (B) SDS-PAGE comparison
between roughly equal amounts of trail and adhesive mucus from the land snail
H. aspersa. Molecular mass markers are in the right lane, from top to
bottom: 205, 116, 97, 84, 66, 55, 45 and 36 kDa.
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Fig. 4. The effect of different concentrations of H. aspersa glue proteins
on citrus pectin mechanics. The storage modulus of 2% citrus pectin was
measured with a dynamic rheometer. Gels contained different concentrations of
glue proteins or BSA as a control. Three comparisons were performed at each
concentration between 0.1 and 1 mg ml1, and two comparisons
were performed at each concentration above 1 mg ml1 (except
at 1.3 mg ml1, which had only one trial). Values are means
± S.E.M. Note that the error bars do
not show up on most of the controls because the variability is so small.
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Fig. 5. The effect of H. aspersa glue proteins on polymers with different
degrees of charge. The storage moduli were measured with a dynamic rheometer.
Gels contained 1 mg ml1 glue proteins (dark bars) or 1 mg
ml1 BSA as a control (light bars). Agarose (0.2%,
N=5), apple pectin (2%, N=7) and methylcellulose (2%,
N=6) are neutral or less charged than agar (0.6%, N=7),
citrus pectin (2%, N=7) and carboxymethylcellulose (2%,
N=7). Values are means ±
S.E.M. Asterisks indicate a significant
difference (t-test or Wilcoxon two-sample test,
P<0.05).
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© The Company of Biologists Ltd 2004