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PubMed1986

Fecundity of Litomosoides carinii (Nematoda, Filarioidea) in vivo and in vitro.

Several parameters concerning the reproduction of Litomosoides carinii were assessed using quantitatively infected cotton rats (Sigmodon hispidus). The course of embryogenesis from the fertilization of eggs to the delivery of the first microfilariae was observed by daily autopsies during prepatency. The duration of embryogenesis in vivo could thus be determined as 18 +/- 2 days. The contents of embryos in the uteri of female worms had been examined at various intervals. At the onset of patency 7-8 weeks p.i. the females were 71 +/- 6 mm long and on average contained 308 X 10(3) embryos/female, of which 19% were pathologically altered. In the middle of patency 16-20 weeks p.i. the females had grown up to 100 +/- 11 mm in length and now contained 509 X 10(3) embryos/female, 25% of them were pathologically altered, the others were normally developed. A positive correlation between the body length of a female worm and its number of embryos in utero was evident. Additionally the percentage of pathologically altered embryos was increased with respect to the age of the worms. The calculated fecundity of a female L. carinii in vivo of around 20 X 10(3) microfilariae/female per day had been confirmed with worms maintained in vitro. Three combinations of media and serum supplements were used and their influence on embryogenesis evaluated.

Animals↗
PubMed1986

Fine structure of adult Litomosoides carinii (Nematoda: Filarioidea).

The fine structure of the body wall and the intestine of male and female Litomosoides carinii was studied in sections through the middle and posterior regions of the worms. In the sublateral cells of the female hypodermis the organelles are arranged in regular layers. The zone with the basal labyrinth is the most prominent layer. The intestinal epithelium of the female worm varies considerably in thickness. The cytoplasm of these cells contains many large droplets. The lateral hypodermal chords of the male worm are very narrow bands. The muscle cells of the male worm are of the circomyarian type, without an afibrillar portion. The intestinal lumen of the male worm is very narrow, and the epithelial cells contain very large droplets. In both sexes the hypodermis contains bacteria. Larger glycogen deposits were absent in the hypodermal chords and in the muscle cells of the midbody regions.

Animals↗
PubMed1982

[Experiments in vitro with Litomosoides carinii (Nematoda: Filarioidea) II. Influence of different sera on the release of microfilariae and experiments on the readiness for copulation of the worms (author's transl)].

When fetal calf serum or human serum is added to the culture medium Tc 199, adult females of Litomosoides carinii release the same amount of microfilariae in vitro as after addition of cotton rat serum. In contrast, in media with serum of Meriones unguiculatus or Mastomys natalensis only a few microfilariae are released; moreover, addition of Mastomys serum immobilizes them. When males and females are kept together, the same amount of microfilariae is released as compared with single females. Worms 4 weeks of age (i.e., about 2 weeks before copulation) maintained in medium Tc 199 with 33% cotton rat serum do not mate (no insemination of the females). However, the females live 18 days (harmonic mean) in vitro and grow on average 5 mm in length (28%) and the males roll up their tails in characteristic manner. Worms 5 or 6 weeks of age kept in pairs for 45 to 6 days in vitro were implanted into cotton rats. In vivo they grew to normal length, copulated and delivered microfilariae into the circulating blood. Females implanted solely into the recipient grew as well but remained sterile; this means that no insemination took place in vitro.

Animals↗
PubMed1986

Histology of adult Litomosoides carinii (Nematoda: Filarioidea).

The histology of male and female Litomosoides carinii was studied in serial sections. The body wall of the female worm consists of a rather thin cuticle, very extended lateral hypodermal chords and small sectors of shallow coelomyarian muscle cells. In the female worm an intestinal lumen is found, which is filled with material throughout the worm's length. Both ovaries are situated close to the posterior end. In both genital tubes all stages of oogenesis and embryogenesis could be observed in approximately equal stages of development in most of the sections. The lateral chords of the male worm are very small, whereas the somatic muscle cells are large and of the circomyarian type. The intestine is a minute tube beside the much thicker testis and vas deferens. Considerable sexual dimorphism could be observed in almost all organs of adult Litomosoides carinii.

Animals↗
PubMed1989

Scanning electron microscopic study of adults and microfilariae of Dunnifilaria meningica (Filarioidea: Onchocercidae).

Dunnifilaria meningica from naturally infected Neotoma micropus in Mexico were studied by scanning electron microscopy (SEM). The anterior end of adults is surrounded by two pairs of buccal and two pairs of cervical papillae. Two amphidial openings lie near the central mouth opening, surrounded by a thick cuticular ring. The cuticular surface of males and females shows fine transversal striations. At the posterior end of the male is a semicircular cloaca, a large preanal central papilla, two pairs of perianal and two pairs of postanal papillae. The short, strong, and almost equal spicules are rolled plates that end in a knob-shaped apex, showing a central groove. In the female, the vulva is located 550 microns from the anterior end. The inconspicuous anus is subterminally situated in the right ventrolateral portion of the posterior end. The anterior tip of the sheathed microfilariae is formed by a cap-like disk. Cuticular annulations were clearly demonstrated across the body.

Animals↗
PubMed1993

Comparative effects of anthelmintics on c-MDH from Molinema dessetae (Nematoda: Filarioidea) and from a mammal.

Malate dehydrogenase (MDH) (E.C.1.1.1.37) activity was detected in the filaria Molinema dessetae at a level similar to those found in other filariae. In M. dessetae, the cytoplasmic form (c-MDH) predominated and the study was performed on partially purified fractions. The pH optimum for oxaloacetate reduction was 6.1, with maximal activity at 7811 nmol min-1 mg protein-1, but high concentrations of oxaloacetate inhibited MDH activity. The Km value for oxaloacetate was determined as 22 microM for M. dessetae c-MDH and 33 microM for mammalian c-MDH. Anthelmintic drugs were compared as potential inhibitors of filarial and mammalian c-MDH. Among the compounds evaluated, amocarzine showed a specific inhibitory effect on filarial c-MDH through only at high concentrations. Suramin alone showed an inhibitory effect at low concentrations (Ki = 1.15 microM) but without selective action towards filarial c-MDH. The suramin type of inhibition was found to be competitive. Suramin probably acts on both enzymes in the same manner. Nevertheless, M. dessetae c-MDH is proposed as a suitable enzyme assay model to screen MDH inhibitors as potential filaricides.

Animals↗
PubMed2002

Deep-etched view of the cuticle of adults of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

The fine structure of the cuticle of the filariid nematode Litomosoides chagasfilhoi is described, based on observations made by transmission electron microscopy and deep-etched replicas. The cuticle consists of a trilaminate epicuticle, the outermost layer that interfaces with the host and four other layers: cortical, intermediate, fibrous and basal. In deep-etched replicas, the cortical layer is formed by a meshwork of globular particles and fibers with a thickness of 4-8 nm. The intermediate layer is electron-lucid and contains a densely-stained line. In deep-etched replicas, it is composed by a meshwork of fibers with longitudinal orientation. The fibrous layer is the thickest and most electron-dense and consists of two types of fibers: thick (9-26 nm) and thin (3-6 nm). The innermost basal layer is intimately associated with the hypodermis. In common with other nematodes, the cuticle of L. chagasfilhoi presents channels that are probably involved in nutrient acquisition and transport.

Animals↗
PubMed2002

Further studies on the structural analysis of the cuticle of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

In order to obtain further information on the structural organization of the cuticle of nematodes, this structure was isolated from adult forms of the filariid Litomosoides chagasfilhoi. The purity of the fraction was determined by light and transmission electron microscopy, deep-etching, high resolution scanning electron microscopy, atomic force microscopy, immunocytochemistry, gel electrophoresis (SDS-PAGE) and Western blot. The epicuticle presented a rugous surface with parallel rows and several globular particles that could be involved in the absorption of nutrients and secretion of products. Analysis by SDS-PAGE of purified cuticles revealed five major polypeptides corresponding to 151, 41, 28, 13 and 11 kDa. A polyclonal antibody against a synthetic 18 amino-acid peptide that corresponds to the sequence of domain E of the Haemonchus contortus3A3 collagen gene recognized several protein bands on the Western blot of purified cuticle, and labeled all cuticular layers, as shown by immunocytochemistry.

Animals↗
PubMed2006

Fine structure and cytochemical analysis of the intestinal wall along the body of adult female of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

Litomosoides chagasfilhoi is a filariid nematode parasite of the abdominal cavity of the wild rodent Akodon cursor (Winge, 1887), that has been described and used in Brazil as a new model for human filariasis. The fine structure of the intestine of this nematode was analyzed based on observations made by light and transmission electron microscopies of serial sections along the body. Cytochemical analysis was carried out to investigate the composition of the intestinal wall. This structure consisted of a basal lamina and an epithelium of variable thickness, composed of cells that have an irregular shape. The cytoplasm of intestinal cells contains few organelles: vacuoles, lysosomal bodies, spheroid bodies, endoplasmic reticulum, and many large lipid droplets. In the anterior portion of the intestine, the lysosomal bodies, spheroid bodies, and vacuoles presented positive reaction for acid phosphatase, and carbohydrates were detected in lysosomal bodies. The midbody and posterior regions presented less organelles and lipid droplets, and nuclei were more abundant. Residues of L-fucose were detected by Ulex europaeus lectin binding in the midbody sections. Basic proteins were associated to lipid droplets, in the posterior region. In the whole extension of the intestine, carbohydrates were detected on tight junctions. These results indicate that the metabolized material in the epithelium can contribute to the microfilariae development and also probably can be involved with the excretory/secretory mechanism of these nematodes.

Acid Phosphatase↗
PubMed1996

Purification and characterization of lactate dehydrogenase isoenzymes 1 and 2 from Molinema dessetae (Nematoda:Filarioidea).

High levels of lactate dehydrogenase (LDH; EC 1. 1. 1. 27) activity have been detected in the filarial worm Molinema dessetae. The two major LDH isoenzymes (LDH1 and LDH2) from female worms were purified by successive chromatography on diethylaminoethyl (DEAE)-Sepharose, carboxymethyl (CM)-Sepharose, and hydroxyapatite columns followed by fast protein liquid chromatography (FPLC)-gel filtration. LDH1 and LDH2 isoenzymes were found to be dimers with subunits of 58 kDa. They had similar properties with regard to substrate and coenzyme affinity. The apparent Michaelis constants (K(m) values; mean +/- SEM, n = 10) were 0.34 +/- 0.04 mM for pyruvate, 0.25 +/- 0.02 mM for reduced nicotinamide adenine dinucleotide (NADH), 2.5 +/- 0.21 mM for lactate, and 0.18 +/- 0.02 mM for NAD, which suggested that pyruvate reduction was the favored reaction. LDH1 and LDH2 were affected by p-chloromercuribenzoate and Hg2+, and such inhibitory effects could be reversed by the addition of thiol compounds (L-cysteine or beta-mercaptoethanol) as observed for mammalian LDH. Oxalate acted as a noncompetitive inhibitor of pyruvate reduction (Ki = 4.7 +/- 0.35 mM; mean +/- SEM, n = 10) and as a competitive inhibitor with lactate (Ki = 2.3 +/- 0.21 mM), whereas oxamate acted as a competitive inhibitor with pyruvate (Ki = 3.3 +/- 0.28 mM) and was noncompetitive with lactate (Ki = 19 +/- 1.2 mM). These substrate analogues exerted similar effects on mammalian LDH, but the inhibition constants were significantly different. The existence of structural and kinetic differences between mammal and filarial LDH isoenzymes prompted us to evaluate them as targets for chemotherapeutic attack.

Animals↗
PubMed1997

Litomosoides chagasfilhoi sp. nov. (Nematoda:Filarioidea) parasitizing the abdominal cavity of Akodon cursor (Winge, 1887) (Rodentia:Muridae) from Brazil.

Litomosoides chagasfilhoi sp. nov., a parasite of the abdominal cavity of the wild rodent Akodon cursor (Winge. 1887), is described herein according to investigations conducted by light and scanning electron microscopy. The leading morphological characteristics of the new species are as follows: the buccal capsule is higher than it is wide and has walls thinner than the lumen, and the left spicule presents a handle longer than the blade, whose edges from large membranous wings folded longitudinally. This new species is different from L. silvai Padilha and Faria, 1977, living in the thoracic cavity of the same host.

Abdomen↗
PubMed2001

Fine structure, freeze-fracture and deep-etch views of the sheath and cuticle of microfilariae of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

The fine structure of the sheath and the cuticle of microfilariae of the filariid Litomosoides chagasfilhoi is described based on observations made using transmission electron microscopy (TEM) and especially on deep-etched replicas of fully developed intrauterine microfilariae and mature stretched microfilariae released by adult females through cultivation in vitro. TEM showed that the sheath was trilaminated. In contrast, in deep-etching replicas the sheath presented two layers: an inner layer composed of tightly arranged globular material, and an outer layer whose external surface was relatively smooth. Both in thin sections and in classical freeze-fracture and deep-etched replicas, the cuticle presented two distinct regions: an external one, corresponding to the trilaminated epicuticle, and an inner one, corresponding to the inner cuticle. Deep-etching replicas revealed that the epicuticle presented several structures on the annulations of the microfilariae and that the inner region was composed by two parallel rows of globular structures.

Animals↗
PubMed1992

Characterization of Ca(2+)-ATPase of Setaria cervi (Nematoda: Filarioidea): effect of phenothiazines and anthelmintics.

1. A Mg2+ independent, Ca(2+)-ATPase requiring high concentrations of Ca2+ (5 mM) for the activation, equally distributed in cuticle-muscular-hypodermis, genital organs and gastrointestinal tissues and mainly localized in 10,000 g pellet fraction, was identified in Setaria cervi, a bovine filarial parasite. 2. Filarial enzyme showed Km value of 3.33 mM for ATP as computed from the double reciprocal Lineweaver-Burk plot. 3. The enzyme could be completely solubilized by sonication with about 4-fold increase in specific activity of the enzyme. 4. The enzyme showed about 2-fold activation by the calmodulin fractions isolated from S. cervi and rat brain homogenates. 5. The enzyme was highly sensitive to inhibition with some phenothiazine derivatives. Trifluoperazine was observed to be the most potent inhibitor followed by promethazine and chlorpromazine. 6. Some anthelmintics viz. diethycarbamazine and centperazine were found to be highly potent inhibitors of the enzyme, significant inhibition of filarial Ca(2+)-ATPase was also observed with levamisole and suramine. 7. Studies indicate Ca(2+)-ATPase of S. cervi as a potential chemotherapeutic target.

Animals↗