Soluble scute proteins of healthy and ill desert tortoises (Gopherus agassizii)

Bruce L. Homer Department of Pathobiology University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.

Search for other papers by Bruce L. Homer in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Chen Li Department of Pathobiology University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.
Intrabiotics Pharmaceuticals Inc, 1255 Terra Bella Ave, Mountain View, CA 94043.

Search for other papers by Chen Li in
Current site
Google Scholar
PubMed
Close
 BVM, MS
,
Kristin H. Berry University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.

Search for other papers by Kristin H. Berry in
Current site
Google Scholar
PubMed
Close
 PhD
,
Nancy D. Denslow College of Veterinary Medicine, and the Center for Biotechnology University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.

Search for other papers by Nancy D. Denslow in
Current site
Google Scholar
PubMed
Close
 PhD
,
Elliott R. Jacobson Department of Small Animal Clinical Sciences University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.

Search for other papers by Elliott R. Jacobson in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Roger H. Sawyer Department of Biological Sciences, University of South Carolina,Columbia, SC 29208.

Search for other papers by Roger H. Sawyer in
Current site
Google Scholar
PubMed
Close
 PhD
, and
J. Elliot Williams Department of Pathobiology University of Florida, Gainesville, FL 32610; the US Geological Survey, 6221 Box Springs Blvd, Riverside, CA 92507.

Search for other papers by J. Elliot Williams in
Current site
Google Scholar
PubMed
Close
 BS

Abstract

Objectives—To characterize protein composition of shell scute of desert tortoises and to determine whether detectable differences could be used to identify healthy tortoises from tortoises with certain illnesses.

Animals—20 desert tortoises.

Procedures—Complete postmortem examinations were performed on all tortoises. Plastron scute proteins were solubilized, scute proteins were separated by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and proteins were analyzed, using densitometry. Two-dimensional immobilized pH gradient-PAGE (2D IPG-PAGE) and immunoblot analysis, using polyclonal antisera to chicken-feather β keratin and to alligator-scale β keratin, were conducted on representative samples. The 14-kd proteins were analyzed for amino acid composition.

Results—The SDS-PAGE and densitometry revealed 7 distinct bands, each with a mean relative protein concentration of > 1%, ranging from 8 to 47 kd, and a major protein component of approximately 14 kd that constituted up to 75% of the scute protein. The 2D IPG-PAGE revealed additional distinct 62- and 68- kd protein bands. On immunoblot analysis, the 14-, 32-, and 45-kd proteins reacted with both antisera. The 14-kd proteins had an amino acid composition similar to that of chicken β keratins. There was a substantial difference in the percentage of the major 14- kd proteins from scute of ill tortoises with normal appearing shells, compared with 14-kd proteins of healthy tortoises.

Conclusions and Clinical Relevance—The major protein components of shell scute of desert tortoises have amino acid composition and antigenic features of β keratins. Scute protein composition may be altered in tortoises with certain systemic illnesses. ( Am J Vet Res 2001;62:104–110)

Abstract

Objectives—To characterize protein composition of shell scute of desert tortoises and to determine whether detectable differences could be used to identify healthy tortoises from tortoises with certain illnesses.

Animals—20 desert tortoises.

Procedures—Complete postmortem examinations were performed on all tortoises. Plastron scute proteins were solubilized, scute proteins were separated by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and proteins were analyzed, using densitometry. Two-dimensional immobilized pH gradient-PAGE (2D IPG-PAGE) and immunoblot analysis, using polyclonal antisera to chicken-feather β keratin and to alligator-scale β keratin, were conducted on representative samples. The 14-kd proteins were analyzed for amino acid composition.

Results—The SDS-PAGE and densitometry revealed 7 distinct bands, each with a mean relative protein concentration of > 1%, ranging from 8 to 47 kd, and a major protein component of approximately 14 kd that constituted up to 75% of the scute protein. The 2D IPG-PAGE revealed additional distinct 62- and 68- kd protein bands. On immunoblot analysis, the 14-, 32-, and 45-kd proteins reacted with both antisera. The 14-kd proteins had an amino acid composition similar to that of chicken β keratins. There was a substantial difference in the percentage of the major 14- kd proteins from scute of ill tortoises with normal appearing shells, compared with 14-kd proteins of healthy tortoises.

Conclusions and Clinical Relevance—The major protein components of shell scute of desert tortoises have amino acid composition and antigenic features of β keratins. Scute protein composition may be altered in tortoises with certain systemic illnesses. ( Am J Vet Res 2001;62:104–110)

Advertisement