Stoma and intestine ultrastructure of the marine free-living nematode Odontophora deconincki (Nematoda: Araeolaimida: Axonolaimidae)

Nematology ◽  
2021 ◽  
pp. 1-18
Author(s):  
Maria A. Fedyaeva ◽  
Alexei V. Tchesunov
Keyword(s):  
Substrate Surface ◽  
Buccal Capsule ◽  
Free Living ◽  
Wide Range ◽  
Free Living Nematode ◽  
Food Particles ◽  
Food Content ◽  
Flocculent Material ◽  
Fine Morphology ◽  
Long Cylinder

Summary The fine morphology of the buccal capsule and intestine (midgut) of the marine free-living nematode Odontophora deconincki was investigated. The cheilostome is armed with six equal claw-like odontia that can evert radially by opening the mouth. Light-refracting accessory buccal structures within the cheilostomatal cuticle alternate with odontia and consist of two elements: anterior armilloids and posterior granular armilliths. The buccal cavity (pharyngostome) is surrounded by a complex of longitudinal and oblique muscles partially attached to the cheilostome cuticle at the sites of the accessory buccal structures and enabling a wide opening of the mouth. With the described stoma condition, the nematode probably scrapes food particles from the substrate surface. In cross-section, the midgut consists of 5-7 cells that appear uniform throughout its length. An extracellular matrix (glycocalyx) over the microvillar brush varies in thickness and stratification depending on presence or absence of food content in the lumen. Abundant spherocrystals (globular inclusions with concentric striations) were present in all gut cells. No indication of endocytosis or digestive vacuoles was observed in the gut cells and extracellular digestion predominates. Most specimens had a gut content formed from a long cylinder of compressed flocculent material with some barely identifiable components and few spherocrystals expelled from the enterocytes. We assume that the nematode diet comprises a wide range of objects, mainly eukariotic epigrowth organisms, which are shorn off and scraped from the surface of sand grains and then ingested.

The buccal capsule of Caenorhabditis elegans (Nematoda: Rhabditoidea): an ultrastructural study

1981 ◽  
Vol 59 (10) ◽  
pp. 1952-1961 ◽  
Author(s):  
K. A. Wright ◽  
J. N. Thomson
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Buccal Capsule ◽  
Nematode Caenorhabditis Elegans ◽  
Free Living ◽  
Dense Granules ◽  
Free Living Nematode ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Esophageal Muscle

The buccal capsule of the free-living nematode Caenorhabditis elegans has been analysed by serial section electron microscopy. Whereas the regions classically identified in the rhabditid buccal capsule can be distinguished, the cuticle lining does not constitute separate cuticular plates, but rather, structural–functional differentiations within a cuticle continuous with that of the esophagus. Only the lip region (cheilostom) is lined by body wall cuticle. The prostom cuticle is underlain by two rings of syncytial arcade cytoplasm connected to nine cell bodies. The mesostom cuticle is underlain by the nonmuscular epithelial cells of the esophagus, whereas the cuticle of the metastom and telostom is underlain by esophageal muscle cells m1 and m2. During moulting, buccal cuticle is produced later than body cuticle and its formation is characterized by accumulation of dense granules in both arcade and esophageal cytoplasm. It is concluded that the buccal capsule should be considered as "astomatous" in the terminology of K. A. Wright.

Two new free-living nematode species (Comesomatidae) from the continental slope of New Zealand, with keys and notes on distribution

Zootaxa ◽  
2012 ◽  
Vol 3348 (1) ◽  
pp. 40 ◽  
Author(s):  
LEDUC D. ◽  
PROBERT P. K. ◽  
NODDER S. D.
Keyword(s):  
Continental Slope ◽  
Nematode Species ◽  
Intestinal Wall ◽  
Free Living ◽  
Related Factors ◽  
Interspecific Differences ◽  
Food Quantity ◽  
Wide Range ◽  
Free Living Nematode ◽  
Effect Of Food

Two new free-living marine nematode species of the family Comesomatidae are described from the continental slope of NewZealand, and their distributions at 32 sites are investigated in relation to environmental factors. Vasostoma aurata n. sp. is char-acterised by a distinctly set-off head, amphideal fovea with 4.5 turns, conspicuous chords consisting of two bands fusing atbody extremities, with outline of cell bodies usually golden-coloured, and relatively short spicules. Setosabatieria conicauda n.sp. is characterised by an amphid with 4.25–4.5 turns, the presence of only 1–3 sub-cephalic setae per file, several clusters ofintracellular inclusions, sometimes brown-coloured, in the intestinal wall, and a conical tail. Keys to all known species of Seto-sabatieria and Vasostoma are provided. Both species were mostly restricted to subsurface (1–5cm depth) sediments. The abun-dance of V. aurata n. sp. and S. conicauda n. sp. was significantly correlated with food quantity and quality, but the patternsdiffered between species. The effect of food-related factors may be directly linked to interspecific differences in food require-ments, or mediated by biogeochemical processes (i.e., tolerance of sub-surface oxygen and sulphide concentrations). No signif-icant correlations were found between sediment granulometry and abundances, despite the wide range of sediment grain-sizes (6–93% silt and clay) at the sampling sites.

scholarly journals Liposome-based transfection enhances RNAi and CRISPR-mediated mutagenesis in non-model nematode systems

2018 ◽  
Author(s):  
Sally Adams ◽  
Prachi Pathak ◽  
Hongguang Shao ◽  
James B. Lok ◽  
Andre Pires-daSilva
Keyword(s):  
Nematode Species ◽  
Strongyloides Stercoralis ◽  
Free Living ◽  
Functional Studies ◽  
Human Parasite ◽  
Wide Range ◽  
Free Living Nematode ◽  
Animal Phyla ◽  
Genomic Studies ◽  
Dauer Larvae

AbstractNematodes belong to one of the most diverse animal phyla. However, functional genomic studies in nematodes, other than in a few species, have often been limited in their reliability and success. Here we report that by combining liposome-based technology with microinjection, we were able to establish a wide range of genomic techniques in the newly described nematode genus Auanema. The method also allowed heritable changes in dauer larvae of Auanema, despite the immaturity of the gonad at the time of the microinjection. As proof of concept for potential functional studies in other nematode species, we also induced RNAi in the free-living nematode Pristionchus pacificus and targeted the human parasite Strongyloides stercoralis.

scholarly journals Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽  
2014 ◽  
Vol 141 (9) ◽  
pp. 1203-1215 ◽  
Author(s):  
VICTORIA GILLAN ◽  
EILEEN DEVANEY
Keyword(s):  
Life Cycle ◽  
Heat Shock Protein 90 ◽  
Ecological Niches ◽  
Actual Number ◽  
Host Organism ◽  
Free Living ◽  
Parasitic Species ◽  
Free Living Nematode ◽  
Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

scholarly journals Haematophagic Caenorhabditis elegans

Parasitology ◽  
2018 ◽  
Vol 146 (3) ◽  
pp. 314-320 ◽  
Author(s):  
Veeren M Chauhan ◽  
David I Pritchard
Keyword(s):  
Caenorhabditis Elegans ◽  
Neutralizing Antibodies ◽  
Fluorescent Microscopy ◽  
Free Living ◽  
C Elegans ◽  
Vaccine Responses ◽  
Nematode Parasites ◽  
Significant Difference ◽  
Free Living Nematode ◽  
Bright Emission

AbstractCaenorhabditis elegans is a free-living nematode that resides in soil and typically feeds on bacteria. We postulate that haematophagic C. elegans could provide a model to evaluate vaccine responses to intestinal proteins from hematophagous nematode parasites, such as Necator americanus. Human erythrocytes, fluorescently labelled with tetramethylrhodamine succinimidyl ester, demonstrated a stable bright emission and facilitated visualization of feeding events with fluorescent microscopy. C. elegans were observed feeding on erythrocytes and were shown to rupture red blood cells upon capture to release and ingest their contents. In addition, C. elegans survived equally on a diet of erythrocytes. There was no statistically significant difference in survival when compared with a diet of Escherichia coli OP50. The enzymes responsible for the digestion and detoxification of haem and haemoglobin, which are key components of the hookworm vaccine, were found in the C. elegans intestine. These findings support our postulate that free-living nematodes could provide a model for the assessment of neutralizing antibodies to current and future hematophagous parasite vaccine candidates.

scholarly journals Intestinal parasite analysis in organic sediments collected from a 16th-century Belgian archeological site

2005 ◽  
Vol 21 (1) ◽  
pp. 329-332 ◽  
Author(s):  
Alexandre Fernandes ◽  
Luiz Fernando Ferreira ◽  
Marcelo Luiz Carvalho Gonçalves ◽  
Françoise Bouchet ◽  
Carlos Henrique Klein ◽  
...  
Keyword(s):  
Intestinal Parasite ◽  
Parasite Burden ◽  
Northern Coast ◽  
Free Living ◽  
High Infection ◽  
Free Living Nematode ◽  
Organic Sediments ◽  
The Village ◽  
Archeological Site ◽  
Organic Remains

Parasite eggs found in organic remains collected from medieval structures in Raversijde (medieval name: Walraversijde), a village on the northern coast of Belgium, are discussed. The eggs were identified as Ascaris lumbricoides and Trichuris trichiura, both human parasites. Species identification allowed elucidating the origin of the organic sediments and the structures, in this case latrines used by humans. Capillaria sp. and free-living nematode larvae were also found in the latrine. Although neither parasite burden nor prevalence rates could be measured, the abundance of human intestinal parasite eggs indicated a high infection rate in the village residents, reflecting very poor sanitation.

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