ABSTRACT
Norepinephrine, 5-hydroxytryptophan, octopamine, dihydroxyphenylacetic acid, N-acetyldopamine, dopamine, 5-hydroxyindoleacetic acid, N-acetylserotonin, tyramine, tryptophan and serotonin in larvae (third free stage and parasitic stages) and adult males and females (at defined ages during the intestinal phase) of the parasitic nematode Nippostrongylus brasiliensis were quantified simultaneously by high-performance liquid chromatography with electrochemical detection. Biogenic amine levels depended on the stage, the age and the sex of parasites and on environmental conditions. Their physiological roles in reproductively competent adults of this nematode are discussed in relation to exuviation and egg laying. Parallel fluctuations in free ecdysteroids and norepinephrine were observed in females from the same worm populations.
Subject(s)
Biogenic Monoamines/metabolism , Nippostrongylus/metabolism , 3,4-Dihydroxyphenylacetic Acid/metabolism , 5-Hydroxytryptophan/metabolism , Animals , Dopamine/analogs & derivatives , Dopamine/metabolism , Ecdysteroids , Female , Hydroxyindoleacetic Acid/metabolism , Insect Hormones/metabolism , Larva/metabolism , Male , Nippostrongylus/growth & development , Nippostrongylus/pathogenicity , Norepinephrine/metabolism , Octopamine/metabolism , Rats , Rats, Wistar , Serotonin/analogs & derivatives , Serotonin/metabolism , Sex Characteristics , Steroids/metabolism , Tryptophan/metabolism , Tyramine/metabolismABSTRACT
Total ecdysteroid-like immunoreactive material was assayed and quantified in adults of the parasitic nematode N. brasiliensis during the intestinal phase in the rat in order to detect possible physiological fluctuations in titre. Worms of the same sex isolated from one rat were pooled in order to quantify ecdysteroids using enzyme immunoassay (EIA). The concentration of ecdysteroids fluctuated during adult life according to the sex and the age of the parasite. Important differences of levels of ecdysteroid-like compounds between the two sexes of parasites were noted particularly at 128 and 168 h post-infection. The peak at 128 h, present in female, but not in male worms, corresponds to the time of egg-laying. Following HPLC-EIA analysis, the presence of ecdysone, 20-hydroxyecdysone and apolar ecdysteroid-like material was ascertained during this peak. The physiological role and the possible origin of ecdysteroids in this nematode are discussed.
Subject(s)
Intestinal Diseases, Parasitic/parasitology , Intestine, Small/parasitology , Invertebrate Hormones/analysis , Nippostrongylus/chemistry , Steroids/analysis , Strongylida Infections/parasitology , Animals , Body Weight , Chromatography, High Pressure Liquid , Ecdysteroids , Feces/parasitology , Female , Immunoenzyme Techniques , Invertebrate Hormones/physiology , Male , Nippostrongylus/anatomy & histology , Nippostrongylus/physiology , Oviposition , Parasite Egg Count , Rats , Rats, Wistar , Steroids/physiologyABSTRACT
Microtopographic features of the various growth stages of the three free-living larval stages of the rat hookworm Nippostrongylus brasiliensis (Nematoda) were surveyed by scanning electron microscopy. These worms have a rounded anterior end and an elongated tail. Cuticular annulations were observed along the body, which also bore two ribbon-like lateral alae. Two rings of six lip-like lappets were observed around the triradiate oral opening in all larval stages. The cephalic space contained two lateral amphidial pits. The excretory pore in the third anterior part was observed in a ventral view of the larvae. No deirids were observed. The anus with a crescent-shape opening was located posteriorly. Phasmidial apertures, only observed in the third-stage larvae, opened on the lateral alae in the tail region.
Subject(s)
Nippostrongylus/growth & development , Animals , Larva/growth & development , Larva/ultrastructure , Microscopy, Electron, Scanning , Nippostrongylus/ultrastructureABSTRACT
Specimens of the rat hookworm, Nippostrongylus brasiliensis (Nematoda) were recovered from lungs (third- and fourth-stage larvae) and intestine (fourth-stage larvae and adults). The following features were studied in the different stages by scanning electron microscopy: cephalic structures, especially sense organs, synlophe, cervical region, and caudal part. The main differences between the third and fourth stages concerned the lip-like structures around the oral aperture, the appearance of the cephalic space with the presence of a cephalic cap in fourth-stage larvae, the pattern of longitudinal ridges, and sexual differentiation. Pore-like papillae, not seen in third-stage larvae, developed in later stages. Deirids were observed only in adults, and phasmids were poorly discerned. Some of these morphological features, such as the cephalic sense organ apertures and cuticle pores and micropores, can be observed only by scanning electron microscopy. The possible functions of these different structures and their relationship with the behavior of the worms during their life cycle are discussed.
