Hu KJ et al. (1999) Nematology "Nematicidal metabolites produced by Photorhabdus luminescens (Enterobacteriaceae), bacterial symbiont of entomopathogenic nematodes."

Hu KJ, Li JX, Webster JM

[Nematology, 1999]

The secondary metabolites, 3,5-dihydroxy-4-isopropylstilbene (ST) and indole, from the culture filtrate of Photorhabdus luminescens MD, were shown to have nematicidal properties. ST caused nearly 100% mortality of 54 and adults of Aphelenchoides rhytium, Bursaphelenchus spp. and Caenorhabditis elegans at 100 mu g/ml, but had no effect on J2 of Meloidogyne incognita or infective juveniles (IJ) of Heterorhabditis megidis at 200 mu g/ml. Indole was lethal to several nematode species at 300 mu g/ml, and caused a high percentage of Bursaphelenchus spp. (54 and adults), M, incognita (J2) and Heterorhabditis spp. (IJ) to be paralysed at 300, 100 and 400 mu g/ml, respectively. Both ST and indole inhibited egg hatch of M, incognita. ST repelled IJ of some Steinernema spp. but not IJ of Heterorhabditis spp., and indole repelled IJ of some species of both Steinernema and Heterorhabditis. ST, but not indole, was produced in nematode-infected larval Galleria mellonella. after 24 h infection.

Serobyan V et al. (2014) Proc Biol Sci "Adaptive value of a predatory mouth-form in a dimorphic nematode."

Sommer RJ, Ragsdale EJ, Serobyan V

[Proc Biol Sci, 2014]

Polyphenisms can be adaptations to environments that are heterogeneous in space and time, but to persist they require conditional-specific advantages. The nematode Pristionchus pacificus is a facultative predator that displays an evolutionarily conserved polyphenism of its mouthparts. During development, P. pacificus irreversibly executes either a eurystomatous (Eu) or stenostomatous (St) mouth-form, which differ in the shape and number of movable teeth. The Eu form, which has an additional tooth, is more complex than the St form and is thus more highly derived relative to species lacking teeth. Here, we investigate a putative fitness trade-off for the alternative feeding-structures of P. pacificus. We show that the complex Eu form confers a greater ability to kill prey. When adults were provided with a prey diet, Eu nematodes exhibited greater fitness than St nematodes by several measures, including longevity, offspring survival and fecundity when followed by bacterial feeding. However, the two mouth-forms had similar fecundity when fed ad libitum on bacteria, a condition that would confer benefit on the more rapidly developing St form. Thus, the two forms show conditional fitness advantages in different environments. This study provides, to our knowledge, the first functional context for dimorphism in a model for the genetics of plasticity.

Zaridah MZ et al. (2001) J Ethnopharmacol "In vitro antifilarial effects of three plant species against adult worms of subperiodic Brugia malayi."

Omar AW, Idid SZ, Zaridah MZ, Khozirah S

[J Ethnopharmacol, 2001]

Five aqueous extracts from three plant species, i.e., dried husks (HX), dried seeds (SX) and dried leaves (LX) of Xylocarpus granatum (Meliaceae), dried stems (ST) of Tinospora crispa (Menispermaceae) and dried leaves (LA) of Andrographis paniculata (Acanthaceae) were tested in vitro against adult worms of subperiodic Brugia malayi. The relative movability (RM) value of the adult worms over the 24-h observation period was used as a measure of the antifilarial activity of the aqueous extracts. SX extract of X. granatum demonstrated the strongest activity, followed by the LA extract of A. paniculata, ST extract of T. crispa, HX extract and LX extract of X. granatum.

Veisseire P et al. (2020) Microorganisms "Investigation into In Vitro and In Vivo Caenorhabditis elegans Models to Select Cheese Yeasts as Probiotic Candidates for their Preventive Effects against Salmonella Typhimurium."

Camares O, Bornes S, Veisseire P, Bonnet M, Poupet C, Callon C, Saraoui T, Chassard C, Gachinat M, Febvre G

[Microorganisms, 2020]

The design of multiscale strategies integrating in vitro and in vivo models is necessary for the selection of new probiotics. In this regard, we developed a screening assay based on the investigation of the potential of yeasts from cheese as probiotics against the pathogen <i>Salmonella</i> Typhimurium UPsm1 (ST). Two yeasts isolated from raw-milk cheese (<i>Saccharomyces cerevisiae</i> 16, Sc16; <i>Debaryomyces hansenii</i> 25, Dh25), as well as <i>S. cerevisiae</i> subspecies <i>boulardii</i> (CNCM I-1079, Sb1079), were tested against ST by applying in vitro and in vivo tests. Adherence measurements to Caco-2 and HT29-MTX intestinal cells indicated that the two tested cheese yeasts presented a better adhesion than the probiotic Sb1079 as the control strain. Further, the Dh25 was the cheese yeast most likely to survive in the gastrointestinal tract. What is more, the modulation of the TransEpithelial Electrical Resistance (TEER) of differentiated Caco-2 cell monolayers showed the ability of Dh25 to delay the deleterious effects of ST. The influence of microorganisms on the in vivo model <i>Caenorhabditis elegans</i> was evaluated by measuring the longevity of the worm. This in vivo approach revealed that this yeast increased the worm's lifespan and protected it against ST infection, confirming that this in vivo model can be useful for screening probiotic cheese yeasts.

Lavigne JP et al. (2013) PLoS One "Virulence of Klebsiella pneumoniae isolates harboring bla KPC-2 carbapenemase gene in a Caenorhabditis elegans model."

Cuzon G, Sotto A, Combescure C, Lavigne JP, Nordmann P, Bourg G

[PLoS One, 2013]

Klebsiella pneumoniae carbapenemase (KPC) is a carbapenemase increasingly reported worldwide in Enterobacteriaceae. The aim of this study was to analyze the virulence of several KPC-2-producing K. pneumoniae isolates. The studied strains were (i) five KPC-2 clinical strains from different geographical origins, belonging to different ST-types and possessing plasmids of different incompatibility groups; (ii) seven transformants obtained after electroporation of either these natural KPC plasmids or a recombinant plasmid harboring only the bla KPC-2 gene into reference strains K. pneumoniae ATCC10031/CIP53153; and (iii) five clinical strains cured of plasmids. The virulence of K. pneumoniae isolates was evaluated in the Caenorhabditis elegans model. The clinical KPC producers and transformants were significantly less virulent (LT50: 5.5 days) than K. pneumoniae reference strain (LT50: 4.3 days) (p&lt;0.01). However, the worldwide spread KPC-2 positive K. pneumoniae ST258 strains and reference strains containing plasmids extracted from K. pneumoniae ST258 strains had a higher virulence than KPC-2 strains belonging to other ST types (LT50: 5 days vs. 6 days, p&lt;0.01). The increased virulence observed in cured strains confirmed this trend. The bla KPC-2 gene itself was not associated to increased virulence.

Garms R (1987) Trop Med Parasitol "Infection rates and parasitic loads of Onchocerca volvulus, and other filariae, in Simulium sanctipauli s.l. and S. yahense in a rain-forest area of Liberia."

Garms R

[Trop Med Parasitol, 1987]

Simulium sanctipauli s.l. and S. yahense are common and widespread in the rain-forest zone of Liberia, but differ with regard to their biting densities and contribution to the transmission of Onchocerca volvulus. Although, in a study area on the St. Pauli River, S. sanctipauli s.l. (presumably S. soubrense in the sense of Post) was the predominant ma-biting species (74.3% of 30,855 females examined), S. yahense was shown to be the important vector. While 1000 biting females of S. yahense carried 96 3rd stage larvae indistinguishable from O. volvulus, only 14 were found per 1000 females of S. sanctipauli s.l. Of the parous females (3135 S. sanctipauli s.l./1621 S. yahense) 23.8/39.9% harboured 1st and/or 2nd stage filarial larvae and 1.9/9.4% 3rd stage larvae of O. volvulus. Animal filariae of unknown origin, indicative of zoophily, were very common in S. sanctipauli s.l. (13.8%) but practically absent from S. yahense (0.5%). In spite of its poorer vectorial performance S. sanctipauli s.l. cannot be neglected as a vector because it may occur in high biting densities and contribute considerably to the transmission, in particular in the vicinity of the St. Paul River. The interplay of two vector species, which develop in different types of water-courses explains the overall high endemicity of onchocerciasis in the study area.

Wylie T et al. (2004) Nucleic Acids Res "Nematode.net: a tool for navigating sequences from parasitic and free-living nematodes."

Dante M, Clifton SW, Mitreva MD, McCarter JP, Wilson RK, Wylie T, Martin JC, Waterston RH, Chinwalla A

[Nucleic Acids Res, 2004]

Nematode.net (www.nematode.net) is a web- accessible resource for investigating gene sequences from nematode genomes. The database is an outgrowth of the parasitic nematode EST project at Washington University's Genome Sequencing Center (GSC), St Louis. A sister project at the University of Edinburgh and the Sanger Institute is also underway. More than 295,000 ESTs have been generated from >30 nematodes other than Caenorhabditis elegans including key parasites of humans, animals and plants. Nematode.net currently provides NemaGene EST cluster consensus sequence, enhanced online BLAST search tools, functional classifications of cluster sequences and comprehensive information concerning the ongoing generation of nematode genome data. The long-term goal of nematode.net is to provide the scientific community with the highest quality sequence information and tools for studying these diverse species.

Hoss S et al. (2009) Ecotoxicol Environ Saf "Assessing the toxicity of contaminated soils using the nematode Caenorhabditis elegans as test organism."

Junker T, Jansch S, Hoss S, Rombke J, Moser T

[Ecotoxicol Environ Saf, 2009]

In this study, nine uncontaminated reference soils and 22 contaminated soils with different physico-chemical properties and contamination patterns were tested with a standardized toxicity test, using the nematode, Caenorhabditis elegans, as test organism. Fertility, growth and reproduction of C. elegans in the soils were compared with the exposure in standard soil Lufa St.2.2. C. elegans showed 100% fertility and a very low variability of growth in the reference soils. Although, reproduction varied considerably between the various reference soils, validity criteria (&gt;30 offspring per test organism) were met in all reference soils. Moreover, Lufa St. 2.2 turned out to be a suitable and representative control soil. In order to clearly classify the effects of the polluted soils on C. elegans, toxicity thresholds were derived for nematode fertility (20% inhibition), growth (10% inhibition) and reproduction (40% inhibition) on the basis of the test inherent variability (MDD=minimal detectable difference), as well as their variability between the uncontaminated reference soils (MTI=maximal tolerable inhibition). The contaminated soils showed clear toxic effects on the nematodes, whereas the toxicity was better correlated to organic than to heavy metal contamination in bulk soil. Interestingly, the results of the nematode toxicity test were not well correlated with those of tests with oligochaetes, collembolans and plants, performed with the same soils, showing that the results are not redundant. The toxicity test using C. elegans turned out to be suitable for testing the toxicity of field collected soils and might by a valuable addition to soil test batteries.

Coomansingh-Springer C et al. (2019) Heliyon "Internal parasitic burdens in brown rats (Rattus norvegicus) from Grenada, West Indies."

Sharma RN, Armstrong E, Vishakha V, Acuna AM, Coomansingh-Springer C

[Heliyon, 2019]

This study identified the endoparasites in Brown rat (<i>Rattus norvegicus)</i> during May to July 2017 in Grenada, West Indies. A total of 162 rats, 76 females and 86 males were trapped from St. George and St. David parishes in Grenada. The collected fecal samples were examined for parasitic eggs and/or oocysts using simple fecal flotation technique. Adult parasites found in the intestinal tract were examined for identification. The overall prevalence of intestinal parasites among rats was 79 %. Ten helminth species were recovered, several of which were reported for the first time in rodents in Grenada. The internal parasites consist of seven nematodes (<i>Angiostrongylus</i> spp., <i>Nippostrongylus braziliensis</i>, <i>Heterakis spumosa</i>, <i>Strongyloides ratti</i>, <i>Aspiculuris tetraptera</i>, <i>Syphacia</i> spp. and <i>Protospirura</i> spp.), one cestode (<i>Hymenolepsis diminuta</i>), one acanthocephalan (<i>Moniliformis moniliformis</i>) and one protozoa species (<i>Eimeria</i> spp.). The most prevalent zoonotic species were <i>Angiostrongylus</i> spp. (35.2%), <i>Hymenolepsis diminuta</i> (7.4%) and <i>Moniliformis moniliformis</i> (3.1%). Several nonzoonotic endoparasites; which included <i>Nippostrongylus braziliensis</i> (50.6%), <i>Heterakis spumosa</i> (15.4%), <i>Strongyloides ratti</i> (43.2%), <i>Aspiculuris tetraptera</i> (2.5%), <i>Syphacia</i> spp<i>.</i> (1.9%), <i>Protospirura</i> spp. (1.2%) and <i>Eimeria</i> spp. (4.7%) were also identified. The most prevalent parasites were <i>Nippostrongylus brasiliensis</i> (50.6%), <i>Strongyloides ratti</i> (43.2%) and <i>Angiostrongylus spp.</i> (35.2%). Co-infections occurred with up to six species per rat showing different combinations of parasitic infections.

Hodgkin J (2017) Genetics "Frontiers of Knowledge: An Interview with 2017 Edward Novitski Prize Recipient Jonathan Hodgkin."

Hodgkin J

[Genetics, 2017]

The Genetics Society of America's Edward Novitski Prize recognizes a single experimental accomplishment or a body of work in which an exceptional level of creativity and intellectual ingenuity has been used to design and execute scientific experiments to solve a difficult problem in genetics. The 2017 winner, Jonathan Hodgkin, used elegant genetic studies to unravel the sex determination pathway in Caenorhabditis elegans He inferred the order of genes in the pathway and their modes of regulation using epistasis analyses-a powerful tool that was quickly adopted by other researchers. He expanded the number and use of informational suppressor mutants in C. elegans that are able to act on many genes. He also introduced the use of collections of wild C. elegans to study naturally occurring genetic variation, paving the way for SNP mapping and QTL analysis, as well as studies of hybrid incompatibilities between worm species. His current work focuses on nematode-bacterial interactions and innate immunity.