scholarly journals Feeding Dimorphism in a Mycophagous Nematode, Bursaphelenchus sinensis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Natsumi Kanzaki ◽  
Taisuke Ekino ◽  
Robin M. Giblin-Davis
Keyword(s):  
Prey Species ◽  
Culture Media ◽  
Morphological Characters ◽  
Free Living ◽  
Ecological Adaptability ◽  
Free Living Nematode ◽  
Food Species ◽  
Phylogenetic Origin ◽  
Biological Characters ◽  
Laboratory Culturing

Abstract Phenotypic plasticity has been widely reported in animals and can drive investment in new biological characters that engender ecological adaptability. The nematode family Diplogastridae, especially Pristionchus pacificus with its dramatic stomatal (feeding) dimorphism, has become an important model system to analyze the evolutionary and developmental aspects of polyphenism. However, this plasticity has not been confirmed in other nematode groups. In the present study, we experimentally examined the feeding dimorphism of a fungal feeding free-living nematode, Bursaphelenchus sinensis. In a laboratory culturing experiment, the nematode expressed dimorphism, i.e., a small proportion of the population manifested as a predatory form. This form only occurred in females and was not clearly influenced by the presence of potential prey species. In addition, the ratio of the predatory form to the mycophagous form varied among different fungal food species grown in monoculture on different culture media. The predatory form of B. sinensis was typologically similar to the monomorphic (specialized) predators belonging to the same family. However, some essential morphological characters were slightly different from the specialized predators, and their behaviours were clearly disparate, suggesting that predation in B. sinensis is derived from a different phylogenetic origin than that of the specialized predators.

Discovery of a free-living nematode phylogenetically related to vertebrate parasites of the genus Strongyloides (Nematoda : Strongyloidoidea): morphological, anatomical and molecular characterisation

2016 ◽  
Vol 30 (4) ◽  
pp. 387
Author(s):  
Ren-E Huang ◽  
Runsheng Li ◽  
Zhongying Zhao
Keyword(s):  
Culture Media ◽  
Large Subunit ◽  
Molecular Genetic ◽  
Small Subunit ◽  
Land Snails ◽  
Rrna Genes ◽  
Lsu Rdna ◽  
Free Living ◽  
Rdna Sequences ◽  
Free Living Nematode

Nematodes are important, largely because they frequently act as parasites and threaten the health of plants, animals and even humans. Here, we describe an interesting free-living nematode from land snails on Luofu Mountain, Guangdong, China. Alloionema luofuensis, sp. nov. is phylogenetically related to slug-parasite A. appendiculatum and the well-known vertebrate parasites Strongyloides spp. based on small subunit (SSU) and the D2-D3 domain of large subunit (LSU) rDNA sequences. The new species possesses an extremely transparent body and is easily maintained using C. elegans culture media, suggesting a possible application prospect of this free-living nematode as a comparative model system for its related parasites. Morphology and anatomy of the gonochoristic A. luofuensis, sp. nov. adult were described and illustrated. The species is characterised by a filiform tail bisexually, ‘rhabditiform’ oesophagus and ‘rhabditid-like’ female anatomy, but its male caudal region is completely different from that of typical rhabditid nematodes, being absent from an enveloping bursa. It is the first marker taxon characterised morphologically as well as molecularly from the family Alloionematidae, a group of nematodes with hyperdiverse molecular genetic variations underlying highly conserved anatomy. Further molecular and genetic studies on A. luofuensis, sp. nov. populations hold promise to provide insight into evolution of the clade consisting of vertebrate parasites of the heterogonic nematode genus Strongyloides. This is because of its unusual high levels of heterozygosity maintained by the conserved rRNA genes of partial SSU and the D2-D3 domain of LSU for the type isolate of this species.

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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