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A method was developed to remove the muscle from body wall strips of adult female Ascaris suum resulting in a hypodermis cuticle preparation. Optimum treatment for obtaining the hypodermis cuticle was a 15 min incubation with trypsin (2.0 mg/ml) at room temperature, followed by mechanical removal of the muscle. The hypodermis cuticle prepared in this manner incorporated radiolabeled amino acids into cuticular and hypodermal proteins; incorporation was inhibited by protein synthesis inhibitors. Characterization of the hypodermal proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the hypodermis apparently contains proteins that differ from those of the cuticle and that the hypodermis of adult A. suum appears to lack cuticle protein precursors. This result will now allow detailed biochemical and physiological investigations of the hypodermis, a tissue which is critical for cuticle synthesis.

Ascaris lumbricoides var. hominis and Ascaridia galli contain 5-hydroxytryptamine, histamine, dopamine, and norepinephrine. The chick parasite showed lower levels of monoamines compared to human ascaris. Amine concentrations in females were higher than in males. In all specimens, 5-hydroxytryptamine was the highest while norepinephrine was found to be uniformly low. The female reproductive organ contained the maximum amount of dopamine while intestine was rich in histamine. A progressive increase in the concentrations of biogenic amines was noticed during development.

Ascaris suum extract was found to contain a mitogenic factor which stimulates human lymphocytes. The extract (100 micrograms protein/ml) induced an increase in [3H]thymidine incorporation into human lymphocytes at a level similar to that obtained with pokeweed mitogen (11 micrograms/ml). Stimulation of mitosis appeared to be more effective with T lymphocytes than non-T lymphocytes. The mitogenic activity of the extract was reduced by only 27% when treated at 56 C for 30 min or when immersed into boiling water for 1 min. The extract was fractionated into four protein peaks by Sephacryl S-200 column chromatography. Lymphocyte mitogenic activity was observed in the first half of the first protein peak. Allergenic activity, assessed by the passive cutaneous anaphylaxis test in rats, was observed in the latter half of the same peak. These results suggest that A. suum contains both an allergen and a mitogenic substance.

Three studies were conducted to examine the function of ecdysteroids in the development of parasitic nematodes. Ecdysone and 20-hydroxyecdysone were extracted, separated chromatographically, and measured in the reproductive tracts of adult female Ascaris suum. Perienteric fluid and the body wall did not contain measurable levels of these steroids. Levels of 20-hydroxyecdysone were correlated with the third and fourth molts of larvae grown in vitro from the third stage. In a bioassay, addition of ecdysteroid extracted from the female reproductive tract or synthetic ecdysteroid increased the proportion of third-stage larvae that molted after 4 days in culture. This evidence supports the role of ecdysteroids in molting in A. suum, as well as suggesting a function in gametogenesis and embryogenesis.

The proteins of the cuticle of adult Ascaris lumbricoides suum were characterized with respect to heterogeneity, glycosylation, and susceptibility to collagenase. Pepsin digestion of intact cuticles was used to determine the extent of stable triple-helical structures of the cuticular components. With sodium dodecyl sulfate-poly-acrylamide gel electrophoresis, it was shown that treatment of purified cuticles with beta-mercaptoethanol released three components (99, 90, and 68 kDa) which comprise 95% of the total solubilized material. The remaining fraction consists of at least four components (16, 28, 154, and 173 kDa). Periodic acid-Schiff staining showed that the only glycoprotein was the 173-kDa component. All cuticular components, except the 173-kDa protein, were degraded by bacterial collagenase. Pepsin digestion of intact cuticles for 24 hr at 4 C produced, after reduction, a 95-kDa fragment; by 96 hr, four fragments (95, 90, 83, and 77 kDa) were evident. When the 96-hr pepsin digest was treated with fresh pepsin, the 77-kDa fragment became the major constituent. With agarose gel electrophoresis, analysis of non-reduced, pepsin-released material revealed intact aggregates that were greater than 2 X 10(3) kDa. The enzyme digestion studies indicate that, with the exception of the 173-kDa component, each cuticular protein contains collagenous domains and that, within the cuticle, the longest contiguous collagen chain in a triple-helical conformation has a uniform molecular size of 77 kDa.