Teulier 2016 Proc Biol Sci
|Teulier L, Weber JM, Crevier J, Darveau CA (2016) Proline as a fuel for insect flight: enhancing carbohydrate oxidation in hymenopterans. Proc Biol Sci 283: 20160333.|
Abstract: Bees are thought to be strict users of carbohydrates as metabolic fuel for flight. Many insects, however, have the ability to oxidize the amino acid proline at a high rate, which is a unique feature of this group of animals. The presence of proline in the haemolymph of bees and in the nectar of plants led to the hypothesis that plants may produce proline as a metabolic reward for pollinators. We investigated flight muscle metabolism of hymenopteran species using high-resolution respirometry performed on permeabilized muscle fibres. The muscle fibres of the honeybee, Apis mellifera, do not have a detectable capacity to oxidize proline, as those from the migratory locust, Locusta migratoria, used here as an outgroup representative. The closely related bumblebee, Bombus impatiens, can oxidize proline alone and more than doubles its respiratory capacity when proline is combined with carbohydrate-derived substrates. A distant wasp species, Vespula vulgaris, exhibits the same metabolic phenotype as the bumblebee, suggesting that proline oxidation is common in hymenopterans. Using a combination of mitochondrial substrates and inhibitors, we further show that in B. impatiens, proline oxidation provides reducing equivalents and electrons directly to the electron transport system. Together, these findings demonstrate that some bee and wasp species can greatly enhance the oxidation of carbohydrates using proline as fuel for flight.
© 2016 The Author(s).
• Keywords: Bees, Evolution, Metabolism, Mitochondria, Pollinators, Proline
• O2k-Network Lab: CA Ottawa Darveau CA
- Mitochondrial respiration when pyruvate (+malate) and proline are combined is more than the sum of respiration rates obtained with substrates used individually. Together, these findings indicate that proline enhances pyruvate oxidation and provides reducing equivalents to the ETS of B. impatiens mitochondria.
Labels: MiParea: Respiration, Comparative MiP;environmental MiP
Organism: Hexapods Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Coupling state: OXPHOS Pathway: F, N, S, Gp, NS, Other combinations, ROX HRR: Oxygraph-2k