Sequence comparison between the flavoprotein subunit of the fumarate reductase (Complex II) of the anaerobic parasitic nematode, Ascaris suum and the succinate dehydrogenase of the aerobic, free-living nematode, Caenorhabditis elegans

SUMMARYThe action of two peptides isolated from the nematode Panagrellus redivivus, PF1 (SDPNFLRFamide) and PF2 (SADPNFLRFamide) have been studied on synaptic transmission in the motornervous system of the parasitic nematode Ascaris suum. Intracellular recordings were made from Ascaris somatic muscle cells and excitatory junction potentials (EJPs) elicited by stimulation of the ventral nerve cord. The EJPs were cholinergic as they were blocked by the Ascaris nicotinic receptor antagonist, benzoquinonium. PF1 caused a slow hyperpolarization, similar to the action of this peptide first reported by Bowman, Geary & Thompson (1990) and further characterized by Franks et al. (1994). The hyper-polarization was accompanied by a marked decrease in the amplitude of the EJPs with an EC50 of 311 ± 30 nM (n = 5). This inhibition is unlikely to be due to a post-synaptic site of action of the peptide as the muscle cell input conductance was not significantly altered by PF1 and furthermore the response to bath-applied acetylcholine was not inhibited by PF1 at concentrations up to 10μM (n = 6). PF2 also inhibited the EJPs in a similar manner to PF1. These studies indicate that both of the peptides isolated from the free-living nematode Panagrellus redivivus have biological activity in the parasitic nematode Ascaris suum. PF1 and PF2 have inhibitory actions in contrast to the predominantly excitatory actions of the Ascaris endogenous peptides AF1 (KNEFIRFamide) and AF2 (KHEYLRFamide). The potent actions of the Panagrellus neuropeptides PF1 and PF2 in Ascaris suggest that peptides with a similar or identical sequence may also occur in Ascarisand have an inhibitory role in the motornervous system.

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Nutritional requirements for pantothenate, pantethine or coenzyme A in the free-living nematode Caenorhabditis elegans

Nematology ◽

10.1163/156854105775142900 ◽

2005 ◽

Vol 7 (5) ◽

pp. 761-766 ◽

Cited By ~ 2

Author(s):

Nancy Lu ◽

Rekha Balachandar

Keyword(s):

Caenorhabditis Elegans ◽

Coenzyme A ◽

Active Form ◽

Calcium Pantothenate ◽

Axenic Medium ◽

Nematode Caenorhabditis Elegans ◽

Free Living ◽

C Elegans ◽

Free Living Nematode ◽

Mild Toxicity

AbstractCaenorhabditis elegans is a free-living nematode cultured in an axenic medium, the Caenorhabditis elegans Maintenance Medium (CeMM), which contains B-vitamins, salts, amino acids, nucleic acid substituents, growth factors and glucose as an energy source. After initial experiments established that either pantothenate or pantethine would satisfy the vitamin B5 requirement in C. elegans, reproduction in the nematodes was measured in eight equimolar concentrations of calcium pantothenate, pantethine or coenzyme A. The optimal levels for pantothenate were found to be 7.5, 30 and 120 μg ml−1. The optimal levels for pantethine and coenzyme A were found to be 35 μg ml−1 and 100 μg ml−1, respectively. Among the three compounds, coenzyme A (at 100 μg/ml) supported a significantly greater population growth and, perhaps, is a more metabolically active form. Mild toxicity was demonstrated for pantothenate at 480μg ml−1, pantethine at 560 and 140 μg ml−1, and coenzyme A was found to exhibit toxicity at 410 and 1700 μg ml−1. Based on our results, we recommend that in the future the CeMM could be supplemented with pantothenate (7.5 μg ml−1) alone.

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The use of Caenorhabditis elegans in parasitic nematode research

Parasitology ◽

10.1017/s003118200400647x ◽

2004 ◽

Vol 128 (S1) ◽

pp. S49-S70 ◽

Cited By ~ 39

Author(s):

J. S. GILLEARD

Keyword(s):

Caenorhabditis Elegans ◽

Parasitic Nematode ◽

Expression System ◽

Nematode Species ◽

Current Status ◽

Evolutionary Development ◽

Parasitic Nematodes ◽

Free Living ◽

C Elegans ◽

Free Living Nematode

There is increasing interest in the use of the free-living nematode Caenorhabditis elegans as a tool for parasitic nematode research and there are now a number of compelling examples of its successful application. C. elegans has the potential to become a standard tool for molecular helminthology researchers, just as yeast is routinely used by molecular biologists to study vertebrate biology. However, in order to exploit C. elegans in a meaningful manner, we need a detailed understanding of the extent to which different aspects of C. elegans biology have been conserved with particular groups of parasitic nematodes. This review first considers the current state of knowledge regarding the conservation of genome organisation across the nematode phylum and then discusses some recent evolutionary development studies in free-living nematodes. The aim is to provide some important concepts that are relevant to the extrapolation of information from C. elegans to parasitic nematodes and also to the interpretation of experiments that use C. elegans as a surrogate expression system. In general, examples have been specifically chosen because they highlight the importance of careful experimentation and interpretation of data. Consequently, the focus is on the differences that have been found between nematode species rather than the similarities. Finally, there is a detailed discussion of the current status of C. elegans as a heterologous expression system to study parasite gene function and regulation using successful examples from the literature.

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Developmental strategies during early embryogenesis of Caenorhabditis elegans

Development ◽

10.1242/dev.97.supplement.31 ◽

1986 ◽

Vol 97 (Supplement) ◽

pp. 31-44

Author(s):

Einhard Schierenberg

Keyword(s):

Caenorhabditis Elegans ◽

Parasitic Nematode ◽

Soil Nematode ◽

Developmental Studies ◽

Central Question ◽

Unique Combination ◽

Nematode Caenorhabditis Elegans ◽

Free Living ◽

C Elegans ◽

Multicellular Structure

How the complex, multicellular structure of an organism is generated from the information contained in the uncleaved egg is a central question in developmental studies. Nematodes are particularly suitable for studying this question. A unique combination of favourable properties, including transparent eggshell, normal embryogenesis under the microscope outside the mother, small number of cells and rapid, reproducible development made nematodes classic models for developmental biologists (for reviews see Chitwood & Chitwood, 1974; von Ehrenstein & Schierenberg, 1980). In addition to the attractive features mentioned above, the free-living soil nematode Caenorhabditis elegans (Fig. 1) is also well suited for analysis of the genetic control of development (Brenner, 1974) unlike the classically studied parasitic nematode Parascaris equorum (Ascaris megalocephala). Recently cellular (e.g. Sulston, Schierenberg, White & Thomson, 1983) and genetic (e.g. Sternberg & Horvitz, 1984) aspects of development have been studied extensively in C. elegans.

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