Unusual intestinal lamellae in the nematodeRhabditophanes sp. KR3021 (Nematoda: Alloinematidae)

Willems, Maxime; Houthoofd, Wouter; Claeys, Myriam; Couvreur, Marjolein; Driessche, Rita Van; Adriaens, Dominique; Jacobsen, Kim; Borgonie, Gaëtan

doi:10.1002/jmor.10332

Cited by 7 publications

(8 citation statements)

References 15 publications

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“…The current study, in corroboration with Kessel et al (1961), Shepherd and Clark (1976) and Willems et al (2005), shows that the morphology of the intestinal microvilli within the phylum Nematoda is more diverse than initially thought. Most remarkable, deviations of the usual finger-like intestinal microvilli have arisen independently several times within the phylum, their occurrence always being in parasitic or in parasitism-related nematodes.…”

Section: Discussionsupporting

confidence: 91%

“…The type I vesicles observed in this study have been described frequently in nematodes as secretion vesicles (Bird & Bird, 1991;Borgonie et al, 1995;Willems et al, 2005) and are reported as having a double membrane (Borgonie et al, 1995). The thread-like type II vesicles that emanate from the top of the microvilli in the intestine of H. gingivalis have also been observed in Hexatylus viviparus (Shepherd & Clark, 1976), a nematode species that has a fungivorous as well as an entomoparasitic lifecycle.…”

Section: Discussionmentioning

confidence: 69%

“…Shepherd and Clark (1976) also reported a few branched microvilli in the intestine of the insect-parasitic H. viviparus. Willems et al (2005) also reported microvilli that deviate from the usual finger-like microvilli in Rhabditophanes sp., a species that may represent a reversal from a parasitic to a non-parasitic lifestyle (Dorris et al, 2002). Microlamellae were observed here instead of cylindrical microvilli.…”

Section: Discussionmentioning

confidence: 91%

“…These lamellae formed a complex 3-D maze network with cavities of varying length. According to Willems et al (2005) the function of the microlamellae network may be related to a maximisation of the intestinal absorption surface. Moreover, by slowing down the movement of the absorbed food through the intestine, more time is available for nutrient uptake and the species is able to survive in an environment with low food availability.…”

Section: Discussionmentioning

confidence: 99%

“…(Jenkins & Erasmus, 1969), Hexatylus viviparus (Shepherd & Clark, 1976) and Rhabditophanes sp. (Willems et al, 2005).…”

mentioning

confidence: 95%

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Intestine ultrastructure of the facultative parasite Halicephalobus gingivalis (Nematoda: Panagrolaimidae)

Fonderie

Willems

Bert

et al. 2009

Nematol

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Halicephalobus gingivalis, classified as a free-living nematode, is a known facultative parasite of horses, zebras and humans. However, detailed information concerning its internal morphology is lacking, especially in relation to possible adaptations to its lifestyle as a facultative parasite. The research presented here uses TEM and PI staining to analyse the morphology of the intestine of H. gingivalis. Specimens cultured under different conditions were included to determine if differences in ultrastructure are induced by culturing method. TEM analysis revealed that the intestinal tract comprises a single layer of cells in which nine pairs of nuclei can be distinguished. Further, unusual dichotomously and trichotomously branched microvilli were observed next to finger-like cylindrical microvilli, the latter being the most commonly described form in nematodes. Finally, three different types of secretion vesicles, i.e., spherical (type I), thread-like (type II) and enlarged globular (type III), occurred independently from each other along the intestinal tract. The relationship of morphological adaptations of the microvilli to parasitism in nematodes is discussed

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

“…(Jenkins & Erasmus, 1969), Hexatylus viviparus (Shepherd & Clark, 1976) and Rhabditophanes sp. (Willems et al, 2005).…”

mentioning

confidence: 95%

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Intestine ultrastructure of the facultative parasite Halicephalobus gingivalis (Nematoda: Panagrolaimidae)

Fonderie

Willems

Bert

et al. 2009

Nematol

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Trophic specialisation of metazoan meiofauna at the Håkon Mosby Mud Volcano: fatty acid biomarker isotope evidence

et al. 2009

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We report the results of a detailed investigation on the trophoecology of two dominant meiofaunal species at the HAyenkon Mosby Mud Volcano (HMMV), a deep-sea cold methane-venting seep. Analyses of fatty acids (FAs) and their stable carbon isotopes were used to determine the importance of chemosynthetic nutritional pathways for the dominant copepod species (morphologically very similar to Tisbe wilsoni) inhabiting the volcano's centre and the abundant nematode Halomonhystera disjuncta from the surrounding microbial mats. The strong dominance of bacterial biomarkers (16:1 omega 7c, 18:1 omega 7c and 16:1 omega 8c) coupled with their individual light carbon isotopes signatures (delta C-13 ranging from -52 to -81aEuro degrees) and the lack of symbiotic relationships with prokaryotes (as revealed by molecular analyses and fluorescent in situ hybridisation) indicated that chemosynthetically derived carbon constitutes the main diet of both species. However, the copepod showed a stronger reliance on the utilisation of methanotrophic bacteria and contained polyunsaturated FAs of bacterial origin (20:5 omega 3 and 22:6 omega 3 with isotope signatures delta C-13 < -80aEuro degrees). Instead, the FA profiles of H. disjuncta suggested that sulphide-oxidising bacteria constituted the main diet of this nematode. Therefore, HMMV can be regarded as a persistent deep-sea cold seep, allowing a chemosynthesis-based trophic specialisation by the dominant meiofaunal species inhabiting its sediments. The present investigation, through the determination of the fatty acid profiles, provides the first evidence for trophic specialisation of meiofauna associated with sub-habitats within a cold seep

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Extended survival of several organisms and amino acids under simulated martian surface conditions

Johnson

Pratt

Vishnivetskaya

et al. 2011

Icarus

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1Recent orbital and landed missions have provided substantial evidence for 2 ancient liquid water on the Martian surface as well as evidence of more recent 3 sedimentary deposits formed by water and/or ice. These observations raise 4 serious questions regarding an independent origin and evolution of life on Mars. 5Future missions seek to identify signs of extinct Martian biota in the form of 6 biomarkers or morphological characteristics, but the inherent danger of space 7 craft-borne terrestrial life makes the possibility of forward contamination a 8 serious threat not only to the life detection experiments, but also to any extant 9Martian ecosystem. A variety of cold and desiccation-tolerant organisms were 10 exposed to 40 days of simulated Martian surface conditions while embedded 11 within several centimeters of regolith simulant in order to ascertain the 12 plausibility of such organisms' survival as a function of environmental parameters 13 and burial depth. Relevant amino acid biomarkers associated with terrestrial life 14 were also analyzed in order to understand the feasibility of detecting biomarker 15 evidence for previous biological activity. Results indicate that stresses due to 16 desiccation, oxidation, and UV-associated damage were the primary deterrent to 17 organism survival, and that the effect of diurnal temperature variations and 18 reactive atmospheric species were minimal. Organisms with resistance to 19 desiccation and radiation environments showed increased levels of survival after 20the experiment compared to organisms characterized as psychrotolerant. Amino 21 2 acid biomarker analyses indicated the presence of an oxidation mechanism that 22 migrated downward through the samples during the course of the experiment and 23 likely represents the formation of various oxidizing species at mineral surfaces as 24 water vapor diffused through the regolith. Current sterilization protocols may 25 specifically select for organisms best adapted to survival at the Martian surface, 26 namely species that show tolerance to radical-induced oxidative damage and low 27 water activity environments. Additionally, any hypothetical Martian ecosystems 28 may have evolved similar physiological traits that allow sporadic metabolism 29 during periods of increased water activity. 30

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Unusual intestinal lamellae in the nematodeRhabditophanes sp. KR3021 (Nematoda: Alloinematidae)

Cited by 7 publications

References 15 publications

Intestine ultrastructure of the facultative parasite Halicephalobus gingivalis (Nematoda: Panagrolaimidae)

Intestine ultrastructure of the facultative parasite Halicephalobus gingivalis (Nematoda: Panagrolaimidae)

Trophic specialisation of metazoan meiofauna at the Håkon Mosby Mud Volcano: fatty acid biomarker isotope evidence

Extended survival of several organisms and amino acids under simulated martian surface conditions

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