Ultrastructure and reconstruction of the pharynx of Leptonemella juliae (Nematoda, Adenophorea)

Hoschitz, Michael; Bright, Monika; Ott, Jörg

doi:10.1007/pl00008498

Cited by 11 publications

(9 citation statements)

References 33 publications

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“…Trichotheristus mirabilis to Sabatieria and Daptonema, permethrin can be particularly effective by ingestion of contaminated detritus. It is known that the pharynx of nematodes is a pumping organ that serves the uptake and transport of food (Hoschitz et al, 2001). There are four cell types in the pharynx: muscle cells, neurons, structural and glandular cells (Albertson & Thomson, 1976).…”

Section: Contribmentioning

confidence: 99%

A microcosm experiment on the effects of permethrin on a free-living nematode assemblage

Sellami

Boufahja

Beyrem

et al. 2011

Nematol

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Microcosms were used to assess the impact of permethrin on the abundance and diversity of free-living marine nematodes. The nematodes were exposed to three permethrin concentrations (50, 100 and 150 μg l–1), and the effects were examined after 25 days. The abundances of nematodes at all permethrin concentrations significantly exceeded those in the controls. Multivariate analyses demonstrated that responses of nematode species to permethrin treatments were varied: Pselionema sp., Prochromadorella neapolitana and Spirinia gerlachi were eliminated at the low dose and seemed to be species intolerant to permethrin; Trichotheristus mirabilis and Xyala striata, which increased with increasing contamination levels, seemed to be 'opportunistic' and/or 'resistant' species. Results showed significant differences between univariate measures of diversity of control nematodes and those from permethrin- contaminated microcosms, where all decreased significantly with increasing abundance of the most tolerant species to permethrin. The use of microcosms has allowed the effects of permethrin on nematodes to be assessed individually, which is not possible in the field.

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Section: Contribmentioning

confidence: 99%

A microcosm experiment on the effects of permethrin on a free-living nematode assemblage

Sellami

Boufahja

Beyrem

et al. 2011

Nematol

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“…Cuticle with very fine annulation. Oesophagus short; the figure of the allotype shows a cervical quotient of about 3 [this figure is 3.4 on the electron micrograph presented by Hoschitz et al (2001)]. …”

Section: Taxonomymentioning

confidence: 99%

“…The symbiotic, uniform bacteria which colonize the surface of the worms in various characteristic patterns are chemoautotrophic oxidizers of sulfide and other reduced sulfur compounds (Schiemer et al 1990;Polz et al 1992Polz et al , 1994Hentschel et al 1999). The nematodes appear to graze on their symbionts (Polz et al 1992;Hoschitz et al 2001), and it has been suggested that the bacterial coat is protective against toxic hydrogen sulfide (Ott 1995;Hentschel et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Leptonemella species (Desmodoridae, Stilbonematinae), benthic marine nematodes with ectosymbiotic bacteria, from littoral sand of the North Sea island of Sylt: taxonomy and ecological aspects

Riemann

Thiermann

Bock

2003

Helgoland Marine Research

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Leptonemella species represent a dominant element of the nematode fauna in sulfidic, deep sediment layers on the sandy shore of Sylt. Based on collections sampled here in 1991-1999, a taxonomic treatise is presented on the three co-existing species, Leptonemella aphanothecae Gerlach, 1950, the closely related L. vicina sp. nov., and L. gorgo Gerlach, 1950. The high incidence of pseudohermaphrodites in the material, mostly functional females with a male copulatory apparatus, is remarkable. The highest population densities of Leptonemella spp. (up to 73 individuals/10 ml sand) were found near polychaete burrows. Because of the great spatial and temporal variations in the oxygen/sulfide regime of these microhabitats, and because of the strong adhesive capabilities of Leptonemella spp., which can anchor themselves firmly to sand grains using caudal glands, we propose that a hemisessile life strategy is employed by these nematodes to fulfill the metabolic needs of their sulfide-oxidizing ectosymbionts.

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“…The bacteria serve as a food source to their host (Schiemer, Novak & Ott, ; Ott et al ., ; Ott, ; Ott, Bright & Bulgheresi, 2004a, b) and probably act as a shield against sulphide poisoning (Hentschel et al ., ). The monophyly of stilbonematins has been stated based on the ultrastructure of the body cuticle (Urbancik, Bauer‐Nebelsick & Ott, 1996a; Urbancik, Novotny & Ott, 1996b), pharynx (Hoschitz, Bright & Ott, ), and glandular sensory organs (Bauer‐Nebelsick et al ., ). Data from DNA sequences also support Stilbonematinae as a clade (van Megen et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Taxonomy of Stilbonematinae (Nematoda: Desmodoridae): description of two new and three known species and phylogenetic relationships within the family

2014

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A taxonomic study of the subfamily Stilbonematinae (Nematoda: Desmodoridae) based on collected specimens from a coral reef in the Caribbean Sea revealed two new species, Laxus parvum sp. nov. and Leptonemella brevipharynx sp. nov. L. parvum is characterized by the small body size (2738 μm), large cephalated spicules (63 μm), wide gubernaculum, and coccoid-shaped ectosymbiotic bacteria. The diagnosis of the genus Laxus is emended and a dichotomous identification key is given for the seven valid species. L. brevipharynx is characterized by the shape of the amphidial fovea, 'open' spiral with 1.25 turns, a short pharynx, hook-shaped gubernaculum, and male tail relatively short. Three known sympatric species, Eubostrichus hopperi, Robbea porosum, and Stilbonema brevicolle, were re-described and illustrated based on morphometric features and morphology from light microscope and scanning electronic microscope observations. For each species, relationships are discussed as well as the diagnostic value of morphological features. Phylogenetic relationships amongst desmodorid species were explored based on small subunit rDNA and cytochrome oxidase c subunit 1 partial loci. The three subfamilies within Desmodoridae (Desmodorinae, Spiriniinae, and Stilbonematinae) are polyphyletic; four of the genera of Stilbonematinae proved to be paraphyletic. Convergent evolution would reconcile the presence of glandular sensory organs and ectosymbiosis with the paraphyly of stilbonematins. The cryptic diversity of R. porosum could be explained by morphological stasis owing to obligate ectosymbiosis with bacteria. The current classification of nine genera is still the most tractable system for Stilbonematinae in spite of the evidence of its paraphyletic nature based on molecular data.

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Ultrastructure and reconstruction of the pharynx of Leptonemella juliae (Nematoda, Adenophorea)

Cited by 11 publications

References 33 publications

A microcosm experiment on the effects of permethrin on a free-living nematode assemblage

A microcosm experiment on the effects of permethrin on a free-living nematode assemblage

Leptonemella species (Desmodoridae, Stilbonematinae), benthic marine nematodes with ectosymbiotic bacteria, from littoral sand of the North Sea island of Sylt: taxonomy and ecological aspects

Taxonomy of Stilbonematinae (Nematoda: Desmodoridae): description of two new and three known species and phylogenetic relationships within the family

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