Uptake of galactose by the epithelial syncytium of Schistosoma mansoni

Podesta, Ron B.; Dean, Lyn L.

doi:10.1016/0166-6851(82)90008-1

Cited by 14 publications

(2 citation statements)

References 8 publications

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“…Indeed, some earlier studies suggest that glucose and glycogen are the sole energy sources for adult F. hepatica (Lloyd, 1986). However, there is evidence for galactose uptake and its incorporation into glycoproteins and glycolipids (Dalton and Joyce, 1987, Hanna, 1976, Podesta and Dean, 1982, Wuhrer, et al, 2004, Wuhrer, et al, 2003.…”

Section: Discussionmentioning

confidence: 99%

A galactokinase-like protein from the liver fluke Fasciola hepatica

Zinsser

Cox

McAuley

et al. 2018

Experimental Parasitology

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Galactokinase catalyses the ATP-dependent phosphorylation of galactose. A galactokinase-like sequence was identified in a Fasciola hepatica EST library. Recombinant expression of the corresponding protein in Escherichia coli resulted in a protein of approximately 50 kDa. The protein is monomeric, like galactokinases from higher animals, yeasts and some bacteria. The protein has no detectable enzymatic activity with galactose or N-acetylgalactosamine as a substrate. However, it does bind to ATP. Molecular modelling predicted that the protein adopts a similar fold to galactokinase and other GHMP kinases. However, a key loop in the active site was identified which may influence the lack of activity. Sequence analysis strongly suggested that this protein (and other proteins annotated as "galactokinase" in the trematodes Schistosoma mansoni and Clonorchis sinensis) are closer to N-acetylgalactosamine kinases. No other galactokinase-like sequences appear to be present in the genomes of these three species. This raises the intriguing possibility that these (and possibly other) trematodes are unable to catabolise galactose through the Leloir pathway due to the lack of a functional galactokinase.

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Section: Discussionmentioning

confidence: 99%

A galactokinase-like protein from the liver fluke Fasciola hepatica

Zinsser

Cox

McAuley

et al. 2018

Experimental Parasitology

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“…The tegument of the adult male Schistosoma mansoni has been studied extensively, especially in regards to the transport of low molecular weight compounds (Pappas & Read, 1975). Trans-tegumental uptake of metabolic substrates (Cornford & Oldendorf, 1979;Podesta & Dean, 1982), purine and pyrimidine transport (Senft, 1972;Levy & Read, 1975), and the permeability and uptake of amino acids (Bruce, Russ, Belusko & Werner, 1972;Asch & Read, 1975;Isseroff, Ertel & Levy, 1976;Chappel & Walker, 1982) have been described biochemically. However, little research has been done on the transport of organic compounds across the tegument in relation to the electrophysiological properties of this structure, even though the biophysical properties of the schistosome tegument have been shown to be similar to those of other multi-dimensional syncytia (Pax, Bricker, Thomspon, Semeyn & Bennett, 1983).…”

Section: Introductionmentioning

confidence: 99%

L-Glutamine: an amino acid required for maintenance of the tegumental membrane potential of Schistosoma mansoni

1987

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SUMMARYThe tegumental membrane potential (–63±2·9 mV) of adult male Schistosoma mansoni in RPMI-1640 is significantly depolarized (–26±7·3 mV) when the parasite is incubated in inorganic media (Hank's Balanced Saline or RPMI-1640 without organic constituents). Of 9 amino acids (L-glutamine, D-glutamine, L-arginine, L-proline, L-aspartate, L-glutamate, L-asparagine, L-isoleucine and L-methionine) L-glutamine alone is sufficient to repolarize the membrane potential to a value (–56±4·5 mV) not significantly different from that found in RPMI-1640. Repolarization by glutamine is dose-dependent, with significant effects obtained as low as 0·10 mM. The concentration of phosphate in the medium also significantly alters the membrane potential. Physiological levels of phosphate (5·6 mM) are necessary in conjunction with L-glutamine to obtain the full repolarization of the membrane potential. In the absence of organic constituents, the membrane potential is strongly dependent on the external medium pH. When L-glutamine is present in the medium, the membrane potential becomes virtually independent of the external pH.

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The Transport of Exogenous Organic Substances by Invertebrate Integuments: Substrate Compartmentalization, Recycling, Epidermal Metabolism, and Transepidermal Transport

Gomme

1985

Proceedings in Life Sciences

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Uptake of galactose by the epithelial syncytium of Schistosoma mansoni

Cited by 14 publications

References 8 publications

A galactokinase-like protein from the liver fluke Fasciola hepatica

A galactokinase-like protein from the liver fluke Fasciola hepatica

L-Glutamine: an amino acid required for maintenance of the tegumental membrane potential of Schistosoma mansoni

The Transport of Exogenous Organic Substances by Invertebrate Integuments: Substrate Compartmentalization, Recycling, Epidermal Metabolism, and Transepidermal Transport

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