Effects of dietary protein concentration on L-proline transport by Manduca sexta midgut

Arthur Woods; M. E. Chamberlin

doi:10.1016/S0022-1910(99)00050-5

Effects of dietary protein concentration on L-proline transport by Manduca sexta midgut

Arthur Woods
, M. E. Chamberlin

Division of Biological and Biomedical Sciences

Ohio University

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

Foliar protein concentrations vary widely. Phytophagous insects may respond to this variation by regulating the rate of absorption of protein breakdown products. Using fifth-instar Manduca sexta reared on artificial diets, we examined whether the rate of L-proline transport across the posterior midgut was affected by dietary protein concentration Caterpillars were reared to the fifth instar on a low- or high-protein diet and then transferred to the same or opposite diet for 24 h prior to the flux measurements. Posterior midguts were mounted in Ussing chambers, and both potential difference and ¹⁴C-proline flux across the tissue were measured during two-hour experiments. Midguts tranSpOrted proline from lumen to hemolymph at about 6.5 μmol/cm²/h and from hemolymph to lumen at less than 0.43 μmol/cm²/h. Only a small fraction was oxidized (0.58 μmol/cm²/h), and proline was not converted to another compound while crossing the midgut epithelium. Neither proline transport rates nor potential differences across the epithelium differed significantly among treatment groups, suggesting that larval M. sexta do not regulate proline transport in response to dietary protein variation.

Original language	English
Pages (from-to)	735-741
Number of pages	7
Journal	Journal of Insect Physiology
Volume	45
Issue number	8
DOIs	https://doi.org/10.1016/S0022-1910(99)00050-5
State	Published - Aug 1999

Funding

We thank C. Breuner, K. Hiruma, R. Huey, P. Jumars, J. Kingsolver, J. Martin, Q. Lan, L. Riddiford, and L. Self for advice and encouragement and L. Riddiford for providing laboratory space. B. Nguyen helped with rearing of the larvae. This work was supported by an NSF predoctoral fellowship to HAW, NSF grant IBN-9407313 to MEC, NSF grant IBN-9419850 and a University of Washington Royalty Research Fund grant to J.G. Kingsolver, and the Department of Zoology at the University of Washington.

Funder number
IBN-9407313, IBN-9419850

Keywords

Dietary regulation
L-proline
Midgut
Protein
Transport

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10.1016/S0022-1910(99)00050-5

Cite this

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title = "Effects of dietary protein concentration on L-proline transport by Manduca sexta midgut",

abstract = "Foliar protein concentrations vary widely. Phytophagous insects may respond to this variation by regulating the rate of absorption of protein breakdown products. Using fifth-instar Manduca sexta reared on artificial diets, we examined whether the rate of L-proline transport across the posterior midgut was affected by dietary protein concentration Caterpillars were reared to the fifth instar on a low- or high-protein diet and then transferred to the same or opposite diet for 24 h prior to the flux measurements. Posterior midguts were mounted in Ussing chambers, and both potential difference and 14C-proline flux across the tissue were measured during two-hour experiments. Midguts tranSpOrted proline from lumen to hemolymph at about 6.5 μmol/cm2/h and from hemolymph to lumen at less than 0.43 μmol/cm2/h. Only a small fraction was oxidized (0.58 μmol/cm2/h), and proline was not converted to another compound while crossing the midgut epithelium. Neither proline transport rates nor potential differences across the epithelium differed significantly among treatment groups, suggesting that larval M. sexta do not regulate proline transport in response to dietary protein variation.",

keywords = "Dietary regulation, L-proline, Midgut, Protein, Transport",

author = "Arthur Woods and Chamberlin, \{M. E.\}",

note = "Funding Information: We thank C. Breuner, K. Hiruma, R. Huey, P. Jumars, J. Kingsolver, J. Martin, Q. Lan, L. Riddiford, and L. Self for advice and encouragement and L. Riddiford for providing laboratory space. B. Nguyen helped with rearing of the larvae. This work was supported by an NSF predoctoral fellowship to HAW, NSF grant IBN-9407313 to MEC, NSF grant IBN-9419850 and a University of Washington Royalty Research Fund grant to J.G. Kingsolver, and the Department of Zoology at the University of Washington.",

year = "1999",

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doi = "10.1016/S0022-1910(99)00050-5",

language = "English",

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AU - Chamberlin, M. E.

N1 - Funding Information: We thank C. Breuner, K. Hiruma, R. Huey, P. Jumars, J. Kingsolver, J. Martin, Q. Lan, L. Riddiford, and L. Self for advice and encouragement and L. Riddiford for providing laboratory space. B. Nguyen helped with rearing of the larvae. This work was supported by an NSF predoctoral fellowship to HAW, NSF grant IBN-9407313 to MEC, NSF grant IBN-9419850 and a University of Washington Royalty Research Fund grant to J.G. Kingsolver, and the Department of Zoology at the University of Washington.

PY - 1999/8

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N2 - Foliar protein concentrations vary widely. Phytophagous insects may respond to this variation by regulating the rate of absorption of protein breakdown products. Using fifth-instar Manduca sexta reared on artificial diets, we examined whether the rate of L-proline transport across the posterior midgut was affected by dietary protein concentration Caterpillars were reared to the fifth instar on a low- or high-protein diet and then transferred to the same or opposite diet for 24 h prior to the flux measurements. Posterior midguts were mounted in Ussing chambers, and both potential difference and 14C-proline flux across the tissue were measured during two-hour experiments. Midguts tranSpOrted proline from lumen to hemolymph at about 6.5 μmol/cm2/h and from hemolymph to lumen at less than 0.43 μmol/cm2/h. Only a small fraction was oxidized (0.58 μmol/cm2/h), and proline was not converted to another compound while crossing the midgut epithelium. Neither proline transport rates nor potential differences across the epithelium differed significantly among treatment groups, suggesting that larval M. sexta do not regulate proline transport in response to dietary protein variation.

AB - Foliar protein concentrations vary widely. Phytophagous insects may respond to this variation by regulating the rate of absorption of protein breakdown products. Using fifth-instar Manduca sexta reared on artificial diets, we examined whether the rate of L-proline transport across the posterior midgut was affected by dietary protein concentration Caterpillars were reared to the fifth instar on a low- or high-protein diet and then transferred to the same or opposite diet for 24 h prior to the flux measurements. Posterior midguts were mounted in Ussing chambers, and both potential difference and 14C-proline flux across the tissue were measured during two-hour experiments. Midguts tranSpOrted proline from lumen to hemolymph at about 6.5 μmol/cm2/h and from hemolymph to lumen at less than 0.43 μmol/cm2/h. Only a small fraction was oxidized (0.58 μmol/cm2/h), and proline was not converted to another compound while crossing the midgut epithelium. Neither proline transport rates nor potential differences across the epithelium differed significantly among treatment groups, suggesting that larval M. sexta do not regulate proline transport in response to dietary protein variation.

KW - Dietary regulation

KW - L-proline

KW - Midgut

KW - Protein

KW - Transport

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SN - 0022-1910

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JO - Journal of Insect Physiology

JF - Journal of Insect Physiology

IS - 8

ER -

Effects of dietary protein concentration on L-proline transport by Manduca sexta midgut

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Keywords

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