Zain MM et al. (2016) Trop Life Sci Res "The Effect of Macrocyclic Lactones-Ivermectin Exposure on Egg Hatching and Larval Development of Caenorhabditis elegans."

Zain MM, Him NA, Yahaya ZS

[Trop Life Sci Res, 2016]

To date, the ivermectin resistance in nematode parasites has been reported and many studies are carried out to determine the causes of this problem. A free-living Caenorhabditis elegans is used as a model system for this study to investigate the response of C. elegans to ivermectin exposure by using larval development assay. Worms were exposed to ivermectin at concentration from 1 ng/mL to 10 ng/mL and dimethyl sulphoxide (DMSO) as a control. The developments of the worms were monitored for 24, 48, 72, and 96 hours until the worms become adults. Results indicated that worms' growth began to be affected by ivermectin at a concentration of 5 ng/mL, while at the concentration of 6, 7, 8, 9, and 10 ng/mL, the growth of worms were inhibited compared to control worms. Further study of the protein expression in C. elegans should be done to investigate the up-regulated and down-regulated proteins involve in ivermectin resistance.

Hussain R et al. (1981) J Immunol "IgE responses in human filariasis. I. Quantitation of filaria-specific IgE."

Ottesen EA, Hussain R, Hamilton RG, Adkinson NF, Kumaraswami V

[J Immunol, 1981]

We have developed a noncompetitive solid phase radioimmunoassay to quantitate human IgE antibodies against soluble adult antigens of Brugia malayi (B.m.), a filarial parasite, in sera of patients with various forms of clinical filariasis in Madras, India. A single reference serum was shown to contain 23 micrograms/ml of B.m.-specific IgE by depletion analysis and was used as a standard serum throughout the study. The levels of specific IgE ranged in the patients sera from 2 to 23,000 ng/ml. When these individuals were divided into clinical groups, the individuals with tropical pulmonary eosinophilia had the highest levels (mean = 8630 ng/ml) and were significantly higher than all the other groups (p less than 0.001). The lowest levels were seen in patients with circulating microfilariae (mean = 30.5 ng/ml). Patients exhibiting lymphatic obstruction (i.e., chronic pathology group) had levels slightly higher than microfilaremics (mean = 68 ng/ml) but were not significantly different (p less than 0.1). Surprisingly, individuals living in endemic areas but who had no clinical signs of filariasis also showed appreciable levels of B.m.-specific IgE (mean = 55 ng/ml). The B.m.-specific IgE represented 0.1 to 48% of the total IgE. High percentages of specific IgE may be responsible for evoking allergic symptomatology in patients with tropical pulmonary eosinophilia.

Haldimann P et al. (2011) J Biol Chem "The novel hydroxylamine derivative NG-094 suppresses polyglutamine protein toxicity in Caenorhabditis elegans."

Goloubinoff P, Muriset M, Vigh L, Haldimann P

[J Biol Chem, 2011]

Aggregation-prone polyglutamine (polyQ) expansion proteins cause several neurodegenerative disorders, including Huntington disease. The pharmacological activation of cellular stress responses could be a new strategy to combat protein conformational diseases. Hydroxylamine derivatives act as co-inducers of heat-shock proteins (HSPs) and can enhance HSP expression in diseased cells, without significant adverse effects. Here, we used Caenorhabditis elegans expressing polyQ expansions with 35 glutamines fused to the yellow fluorescent protein (Q35-YFP) in body wall muscle cells as a model system to investigate the effects of treatment with a novel hydroxylamine derivative, NG-094, on the progression of polyQ diseases. NG-094 significantly ameliorated polyQ-mediated animal paralysis, reduced the number of Q35-YFP aggregates and delayed polyQ-dependent acceleration of aging. Micromolar concentrations of NG-094 in animal tissues with only marginal effects on the nematode fitness sufficed to confer protection against polyQ proteotoxicity, even when the drug was administered after disease onset. NG-094 did not reduce insulin/insulin-like growth factor 1-like signaling, but conferred cytoprotection by a mechanism involving the heat-shock transcription factor HSF-1 that potentiated the expression of stress-inducible HSPs. NG-094 is thus a promising candidate for tests on mammalian models of polyQ and other protein conformational diseases.

Karin Kiontke et al. (2007) International Worm Meeting "Evolution of male ray patterns in rhabditid nematodes."

Rocio Ng, Karin Kiontke, David H. A. Fitch, Alena Kolychkina

[International Worm Meeting, 2007]

One of the most important diagnostic character for nematodes related to C. elegans is the pattern of sensory organs—rays (genital papillae) and phasmids—in the male tail. This pattern is highly conserved within a species, but it varies between species and groups of species. Our objective is to establish the ray pattern in the stem species of rhabditids and to reconstruct the evolutionary changes which occurred within this taxon. Specifically, we look at the number of rays, the arrangement of homologous rays, and the position of phasmids relative to rays in adults and during development using DIC microscopy, MH27 antibody staining of adherens junctions, and cell ablations. Projecting the character differences onto a phylogenetic tree for rhabditids, we determine the number and kinds of evolutionary changes. We find that the number of rays was fixed early in rhabditid evolution to 9 pairs, just as the number of digits was fixed early in vertebrate evolution to 5. Later, several losses of rays but no gain occurred. Our methods allow us to homologize individual rays in the different species and thus to reconstruct the changes in their position. A significant change is the pronounced posterior and dorsad displacement of the first ray in diplogastrids. The position of the phasmids was posterior of all rays in the rhabditid stem species. Several changes to a more anterior and more dorsal position occurred within rhabditids. The change is in every case due to a migration of rays and/or phasmids or their precursors during development. The migration can happen early in L1 or L2 (as in diplogastrids), or very late during ray morphogenesis in L4 (as in Brevibucca saprophaga). Some ray pattern characters support relationships which are otherwise only supported by molecular data. Most importantly, an anterior position of the phasmids supports a relationship of Rhabditoides inermiformis and R. regina with Pleiorhabditis.

Lobos E et al. (2003) Infect Immun "Elevated immunoglobulin E against recombinant Brugia malayi gamma-glutamyl transpeptidase in patients with bancroftian filariasis: association with tropical pulmonary eosinophilia or putative immunity."

Nutman TB, Hothersall JS, Moncada S, Lobos E

[Infect Immun, 2003]

A major allergen of the lymphatic filarial nematode Brugia malayi, a homologue of gamma-glutamyl transpeptidase (gamma-GT), is involved in the pathology of tropical pulmonary eosinophilia (TPE) through its potent allergenicity and the induction of antibodies against the host pulmonary epithelium. To investigate the immunoglobulin G (IgG) subclass and IgE responses to recombinant B. malayi gamma-GT, we analyzed the results obtained from 51 patients with differing clinical manifestations of bancroftian filariasis. gamma-GT-specific IgG1, rather than IgG4, was the predominant IgG subclass, particularly in patients with TPE (geomean, 6,321 ng/ml; range, 78 to 354,867 ng/ml) and was 75 times higher than in patients with elephantiasis (CP) (P < 0.003) and 185 times higher than in endemic normal individuals (ENL) (P < 0.010). IgG2 responses were low and IgG3 was almost absent, with no significant differences among the groups. gamma-GT-specific IgG4 responses were significantly elevated in those with subclinical microfilaremia (MF) compared to the CP and ENL groups and correlated with the presence of circulating filarial antigen (CAg). More significantly, gamma-GT-specific IgE antibody levels were strikingly elevated in patients with TPE (geomean, 681 ng/ml; range, 61 to 23,841 ng/ml) and in the ENL group (geomean, 106 ng/ml; range, 13 to 1,405 ng/ml) whereas the gamma-GT-specific IgE level was 44 and 61 times lower in those with MF and CP, respectively (P < 0.001). Elevated gamma-GT-specific IgE/IgG4 ratios were demonstrated in patients with TPE (ratio, 45) and ENL (ratio, 107). Because expression of gamma-GT in Brugia infective third-stage larvae (L3) was demonstrated by immunoblot analysis, the elevated gamma-GT-specific IgE antibodies appear to be associated not only with pulmonary pathology but also with possible resistance to infection in lymphatic filariasis.

Merris M et al. (2003) J Lipid Res "Sterol effects and sites of sterol accumulation in Caenorhabditis elegans: developmental requirement for 4alpha-methyl sterols."

Khamrai U, Merris M, Chitwood DJ, Lenard J, Bittman R, Wadsworth WG

[J Lipid Res, 2003]

Caenorhabditis elegans requires sterol, usually supplied as cholesterol, but this is enzymatically modified, and different sterols can substitute. Sterol deprivation decreased brood size and adult growth in the first generation, and completely, reversibly, arrested growth as larvae in the second. After one generation of sterol deprivation, 10 ng/ml cholesterol allowed delayed laying of a few eggs, but full growth required 300 ng/ml. C. elegans synthesizes two unusual 4alpha-methyl sterols (4MSs), but each 4MS supported only limited growth as the sole sterol. However, addition of only 10 ng of cholesterol to 1,000 ng of 4MS restored full growth and egg-laying, suggesting that both a 4MS and an unmethylated sterol are required for development. Filipin stained sterols in only a few specific cells: the excretory gland cell, two amphid socket cells, two phasmid socket cells and, in males, spicule socket cells. Sterols were also present in the pharynx and in the intestine of feeding animals in a proximal-to-distal gradient. This non-random sterol distribution, the low concentration requirements, and the effects of 4MSs argues that sterols are unlikely to be used for bulk structural modification of cell membranes, but may be required as hormone precursors and/or developmental effectors.

Pertel R et al. (1974) Comp Gen Pharmacol "Histamine content of the nematode, Caenorhabditis elegans."

Pertel R, Wilson SH

[Comp Gen Pharmacol, 1974]

1. The histamine contect in axenically grown nematodes was found to be 350 ng. per g. wet weight. 2. Histamine content was determined in extracts from the free-living nematode, Caenorhabditis elegans var. Bristol (strain B1-Pl) by an isotope dilution procedure which obviated error encountered in a conventional fluorescence assay. 3. This is the first report of histamine in the Nematoda.

Shu EN et al. (2000) Acta Trop "Ivermectin: concentration-dependent effects on adenosine triphosphatases in adult worms of Onchocerca volvulus."

Okonkwo PO, Onyeanusi J, Shu EN, Batey WO

[Acta Trop, 2000]

The effect of increasing concentrations of ivermectin on adenosine triphosphatase (ATPase) activity was investigated in adult worms of Onchocerca volvulus. Mean Mg- and Na,K-ATPase activities decreased significantly (F ratio = 29.82, P &lt; 0.01 and F ratio = 28.54, P &lt; 0.01, respectively) with increasing concentrations of ivermectin (0-100 ng/ml) in the female worms. When male and female worms were mixed with equal amounts of proteins from each, only the Na,K-ATPase activity was significantly decreased (F ratio = 56.61, P &lt; 0.01) over a similar range of ivermectin concentrations. Since ivermectin exhibits concentration-dependent effects on both ATPases in female adult worms, this might provide an insight into other effects of the drug. However, the adjustment of the dose of ivermectin to obtain a nodular concentration of at least 40 ng/ml is therefore recommended in the complete chemotherapy of onchocerciasis.

Ju J et al. (2023) Aquat Toxicol "The growth toxicity and neurotoxicity mechanism of waterborne TBOEP to nematodes: Insights from transcriptomic and metabolomic profiles."

Wu X, Zhu Y, Wang Y, Ma S, Ju J, Zhang C, Ge W, Mao W

[Aquat Toxicol, 2023]

Tris(2-butoxy) ethyl phosphate (TBOEP) is a typical organophosphorus flame retardant (OPFR), which has been detected in natural water bodies and drinking water and has reached a certain concentration. As a new type of organic pollutant, the environmental health risk of TBOEP needs to be assessed urgently. Here, Caenorhabditis elegans were exposed to 0, 50, 500, and 5000&#xa0;ng/L TBOEP in water for 72&#xa0;h. The results showed that TBOEP exposure caused concentration-dependent inhibition to the growth of nematodes, while exposure to 5000&#xa0;ng/L TBOEP significantly inhibited the locomotor behavior of nematodes. Transcriptomic and metabolomic analysis showed that the disturbances in neurotransmitter transmission and amino acid, carbohydrate, and lipid metabolism were the reason for the neurotoxicity and growth toxicity of TBOEP to nematodes. These results provide basic data and a theoretical basis for evaluating the environmental health risks of organophosphorus flame retardants.

Buchter V et al. (2020) ACS Infect Dis "Characterization of moxidectin against Strongyloides ratti: in vitro and in vivo activity and pharmacokinetics in the rat model."

Haberli C, Hofmann D, Buchter V, Keiser J

[ACS Infect Dis, 2020]

Strongyloides stercoralis is a soil transmitted helminth (STH) affecting an estimated 30-100 million people. Since the infection may be severe and life-threatening, accessible and effective treatment is pivotal. Currently, ivermectin is the drug of choice but has limitations. Moxidectin, a veterinary anthelminthic approved for use in human onchocerciasis, is a promising drug alternative against strongyloidiasis. In this study, we evaluated the in vitro activity of moxidectin on Strongyloides ratti larvae (L3) and adult females, and the activity as well as the pharmacokinetics of moxidectin in S. ratti infected rats. In vitro, moxidectin was similarly active than ivermectin, with LC50 values for L3 and adults in the range of 0.08 to 1.44 M, after 72 hours of exposure. In vivo, doses of 250, 500 and 750 g/kg of moxidectin resulted in a reduction of the worm burden ranging from 48.5-75%. At the highest dose (750 g/kg) we observed a maximal concentration (Cmax) of 50.3 ng/ml and an area under the curve (AUC0-t) of 895.2 ng*h/ml. The half-life in rats was 9 hours and moxidectin was cleared to undetectable blood levels within 7 days (&lt;10 ng/ml). No exposure-response relationship was observed. This work contributes to the characterization of moxidectin in the treatment of S. ratti as a model of Strongyloides spp. and as such, supports moving moxidectin further along the drug development pipeline in the treatment of human strongyloidiasis.