First published online March 14, 2008
Journal of Experimental Biology 211, 1131-1140 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.015313
Matched regulation of gastrointestinal performance in the Burmese python, Python molurus
Christian L. Cox* and
Stephen M. Secor
Department of Biological Sciences, The University of Alabama, Tuscaloosa,
AL 35487-0344, USA
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Fig. 1. Total, mucosal and serosal wet mass of the stomach and small intestine, and
pancreas wet mass of Python molurus as a function of days
postfeeding. Note the postprandial increase in the mass of the pancreas and
small intestine, and the lack of change in stomach and intestinal serosal
mass. In this and similar figures, error bars indicate ± 1 s.e.m. and
are omitted if the s.e.m. is smaller than the width of the symbol used for the
mean value.
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Fig. 2. Mucosal, serosal and total wet mass averaged over all time points for five
intestinal segments of Python molurus, with segment A the most
proximal and E the most distal. Note the gradual decline in tissue mass from
the proximal to distal ends of the small intestine.
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Fig. 3. Stomach contents (% of meal mass), gastric evacuation rate and small
intestine (SI) contents (in g) as a function of days postfeeding of Python
molurus. Gastric evacuation rate is defined as the difference between
individual stomach contents and the mean stomach contents of the immediately
previous sampling period divided by the time elapsed between those sampling
times. Note between 12 h and 3 days postfeeding that much of the ingested meal
passes from the stomach into the small intestine.
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Fig. 4. Gastric mucosal pepsin activity and capacity as a function of days
postfeeding for Python molurus. Note the rapid postprandial decline
in mucosal pepsin, indicating the release of the precursor pepsinogen which is
converted to the proteolytic pepsin.
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Fig. 5. Pancreatic trypsin and amylase activity (top panel) and capacity (bottom
panel) as a function of days postfeeding for Python molurus. Trypsin
activity of the intestinal luminal fluid (0.5–6 days after feeding) is
also presented in the top left panel. Both pancreatic enzymes experience a
rapid upregulation in capacity after feeding.
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Fig. 6. Intestinal aminopeptidase-N and maltase activity of each intestinal segment
(A, B, C, D and E) of Python molurus. Note the postprandial increase
in hydrolase activity for much of the python's small intestine.
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Fig. 7. Aminopeptidase-N (APN) and maltase activity averaged over all sampling
periods for each intestinal segment (A, B, C, D and E) of Python
molurus. Note the decline distally in activity for both hydrolases. In
this and the following bar graphs, error bars indicate ± 1 s.e.m. and
different letters above the bars denote significant (P<0.05)
differences between means as determined from post-hoc pairwise
comparisons.
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Fig. 8. Intestinal aminopeptidase-N (APN) and maltase capacity as a function of
days postfeeding for Python molurus. Both intestinal APN and maltase
capacity increase rapidly after feeding before returning to prefeeding values
by day 10.
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Fig. 9. Intestinal L-leucine, L-proline and
D-glucose uptake capacities as a function of days postfeeding for
Python molurus. Note that the y-axis scales are different
for the three different nutrient transporters. Pythons experience significant
postprandial increases in uptake capacities for the three nutrients.
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Fig. 10. Capacities of enzyme activities and nutrient transport in Python
molurus. Each graph (previously presented in Figs
4,
5,
8 and
9) represents the capacity of
enzyme activity or nutrient activity (µmol min–1) as a
function of days postfeeding. Graphs are located above and below the organ
from which the respective enzymes originate. Note the synchronous regulatory
response of components of both protein and carbohydrate digestion and
absorption for these pythons.
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Fig. 11. Transmission electron micrographs of gastric oxyntopeptic and pancreatic
acinar cells of fasted (left) and fed (right) Python molurus. Note
the numerous zymogen granules containing inactive enzymes within the
oxyntopeptic cells of fasted pythons and within the acinar cells of fed
pythons. By contrast, oxyntopeptic cells of fed snakes and acinar cells of
fasted snakes possessed few zymogen granules. Scale bars, 1 µm.
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© The Company of Biologists Ltd 2008
