Wang XJ et al. (2011) Bioorg Med Chem Lett "A novel macrocyclic lactone with insecticidal bioactivity from Streptomyces microflavus neau3."

Xiang WS, Wang JD, Wang XJ, Yan YJ, Zhang H, Gong DL, Liu CX, Zhang J

[Bioorg Med Chem Lett, 2011]

A novel macrocyclic lactone (1) was isolated from the fermentation broth of Streptomycesmicroflavus neau3, and the structure was elucidated by extensive spectroscopic analysis. Compound 1 showed high acaricidal activity against adult mites (IC(50)=11.1 g mL(-1)), and nematocidal activity against Caenorhabditis elegans (IC(50)=17.4 g mL(-1)), especially the acaricidal activity against mite eggs with an IC(50) of 37.1 g mL(-1), which was relative higher than that of the commercial acaricide and nematocide milbemycins A(3)/A(4).

Desrivot J et al. (2007) J Ethnopharmacol "Antiparasitic activity of some New Caledonian medicinal plants."

Desrivot J, Herrenknecht C, Fournet A, Cabalion P, Waikedre J, Hocquemiller R, Bories C

[J Ethnopharmacol, 2007]

Twenty-nine extracts of 18 medicinal plants used in New Caledonia by traditional healers to treat inflammation, fever and in cicatrizing remedies were evaluated in vitro against several parasites (Leishmania donovani, Trypanosoma brucei brucei, Trichomonas vaginalis and Caenorhabditis elegans). Among the selected plants, Scaevola balansae and Premna serratifolia L. were the most active against Leishmania donovani with IC(50) values between 5 and 10mug/ml. The almond and aril extracts from Myristica fatua had an IC(50) value of 0.5-5mug/ml against Trypanosoma brucei brucei. Only Scaevola balansae extract presented a weak activity against Trichomonas vaginalis. The almond extract from Myristica fatua presented significant activity against Caenorhabditis elegans (IC(50) value of 6.6+/-1.2mug/ml).

Skerniskyte J et al. (2019) BMC Microbiol "Blp1 protein shows virulence-associated features and elicits protective immunity to Acinetobacter baumannii infection."

Karazijaite E, Briandet R, Armalyte J, Deschamps J, Suziedeliene E, Krasauskas R, Skerniskyte J

[BMC Microbiol, 2019]

BACKGROUND: Multidrug resistant Acinetobacter baumannii is one of the major infection agents causing nosocomial pneumonia. Therefore, new therapeutic approaches against this bacterium are needed. Surface-exposed proteins from bacterial pathogens are implicated in a variety of virulence-related traits and are considered as promising candidates for vaccine development. RESULTS: We show in this study that a large Blp1 protein from opportunistic pathogen A. baumannii is encoded in all examined clinical strains of globally spread international clonal lineages I (IC I) and II (IC II). The two blp1 gene variants exhibit lineage-specific distribution profile. By characterization of blp1 deletion mutants and their complementation with blp1 alleles we show that blp1 gene is required for A. baumannii biofilm formation and adhesion to epithelial cells in IC I strain but not in the IC II strain. Nevertheless both alleles are functional in restoring the deficient phenotypes of IC I strain. Moreover, the blp1 gene is required for the establishing of A. baumannii virulence phenotype in nematode and murine infection models. Additionally, we demonstrate that C-terminal 711 amino acid fragment of Blp1 elicits an efficient protection to lethal A. baumannii infection in a murine model using active and passive immunization approaches. Antiserum obtained against Blp1-specific antigen provides opsonophagocytic killing of A. baumannii in vitro. CONCLUSIONS: Lineage-specific variants of surface-exposed components of bacterial pathogens complicate the development of new therapeutic approaches. Though we demonstrated different impact of Blp1 variants on adherence of IC I and IC II strains, Blp1-specific antiserum neutralized A. baumannii strains of both clonal lineages. Together with the observed increased survival rate in vaccinated mice these results indicate that A. baumannii Blp1 protein could be considered as a new vaccine candidate.

Zhou Y et al. (2018) ACS Chem Biol "Tryptophan Metabolism in Caenorhabditis elegans Links Aggregation Behavior to Nutritional Status."

Butcher RA, Zhou Y, Zhang X

[ACS Chem Biol, 2018]

Caenorhabditis elegans uses aggregation pheromones to communicate its nutritional status and recruit fellow members of its species to food sources. These aggregation pheromones include the IC-ascarosides, ascarosides modified with an indole-3-carbonyl (IC) group on the 4'-position of the ascarylose sugar. Nothing is known about the biosynthesis of the IC modification beyond the fact that it is derived from tryptophan. Here, we show that C. elegans produces endogenously several indole-containing metabolites, including indole-3-pyruvic acid (IPA), indole-3-acetic acid (IAA; auxin), and indole-3-carboxylic acid, and that these metabolites are intermediates in the biosynthetic pathway from tryptophan to the IC group. Stable isotope-labeled IPA and IAA are incorporated into the IC-ascarosides. Importantly, we show that flux through the biosynthetic pathway is affected by the activity of the pyruvate dehydrogenase complex (PDC). Knockdown of the PDC by RNA interference leads to an accumulation of upstream metabolites and a reduction in downstream metabolites in the pathway. Our results show that production of aggregation pheromones is linked to PDC activity and that aggregation behavior may reflect a favorable metabolic state in the worm. Lastly, we show that treatment of C. elegans with indole-containing metabolites in the pathway induces the biosynthesis of the IC-ascarosides. Because the natural environment of C. elegans is rotting plant material, indole-containing metabolites in this environment could potentially stimulate pheromone biosynthesis and aggregation behavior in the worm. Thus, there may be important links between tryptophan metabolism in C. elegans and in plants and bacteria that enable interkingdom signaling.

Zhou Y et al. (2018) Elife "Biosynthetic tailoring of existing ascaroside pheromones alters their biological function in C. elegans."

Jones Lipinski RA, Zhou Y, Bhar S, Feng L, Wang Y, Butcher RA, Zhang X, Han J

[Elife, 2018]

<i>Caenorhabditis elegans</i> produces ascaroside pheromones to control its development and behavior. Even minor structural differences in the ascarosides have dramatic consequences for their biological activities. Here, we identify a mechanism that enables <i>C. elegans</i> to dynamically tailor the fatty-acid side chains of the indole-3-carbonyl (IC)-modified ascarosides it has produced. In response to starvation, <i>C. elegans</i> uses the peroxisomal acyl-CoA synthetase ACS-7 to activate the side chains of medium-chain IC-ascarosides for -oxidation involving the acyl-CoA oxidases ACOX-1.1 and ACOX-3. This pathway rapidly converts a favorable ascaroside pheromone that induces aggregation to an unfavorable one that induces the stress-resistant dauer larval stage. Thus, the pathway allows the worm to respond to changing environmental conditions and alter its chemical message without having to synthesize new ascarosides de novo. We establish a new model for biosynthesis of the IC-ascarosides in which side-chain -oxidation is critical for controlling the type of IC-ascarosides produced.

Bush E et al. (2009) Invert Neurosci "The actions of chloride channel blockers, barbiturates and a benzodiazepine on Caenorhabditis elegans glutamate- and ivermectin-gated chloride channel subunits expressed in Xenopus oocytes."

Bush E, Foreman R, Walker RJ, Holden-Dye L

[Invert Neurosci, 2009]

The pharmacology of Caenorhabditis elegans glutamate-gated chloride (GluCl) channels was determined by making intracellular voltage-clamp recordings from Xenopus oocytes expressing GluCl subunits. As previously reported (Cully et al. 1994), GluClalpha1beta responded to glutamate (in a picrotoxin sensitive manner) and ivermectin, while GluClbeta responded only to glutamate and GluClalpha1 only to ivermectin. This assay was used to further investigate the action of chloride channel compounds. The arylaminobenzoate, NPPB, reduced the action of glutamate on the heteromeric GluClalpha1beta channel (IC(50) 6.03 +/- 0.81 microM). The disulphonate stilbene, DNDS, blocked the effect of both glutamate and ivermectin on GluClalpha1beta channels, the action of glutamate on GluClbeta subunits, and the effect of ivermectin on GluClalpha1 subunits (IC(50)s 1.58-3.83 microM). Surprisingly, amobarbital and pentobarbital, otherwise known as positive allosteric modulators of ligand-gated chloride channels, acted as antagonists. Both compounds reduced the action of glutamate on the GluClalpha1beta heteromer (IC(50)s of 2.04 +/- 0.5 and 17.56 +/- 2.16 microM, respectively). Pentobarbital reduced the action of glutamate on the GluClbeta homomeric subunit with an IC(50) of 0.59 +/- 0.09 microM, while reducing the responses to ivermectin on both GluClalpha1beta and GluClalpha1 with IC(50)s of 8.7 +/- 0.5 and 12.9 +/- 2.5 microM, respectively. For all the antagonists, the mechanism is apparently non-competitive. The benzodiazepine, flurazepam had no apparent effect on these glutamate- and ivermectin-gated chloride channel subunits. Thus, arylaminobenzoates, disulphonate stilbenes, and barbiturates are non-competitive antagonists of C. elegans GluCl channels.

Olounlade PA et al. (2012) Parasitol Res "In vitro anthelmintic activity of the essential oils of Zanthoxylum zanthoxyloides and Newbouldia laevis against Strongyloides ratti."

Moulis C, Ha TB, Hoste H, Olounlade PA, Leroy E, Azando EV, Magnaval JF, Valentin A, Fabre N, Hounzangbe-Adote MS

[Parasitol Res, 2012]

The need for new anthelmintic with no chemical residues is becoming urgent. In a program aiming at the evaluation of plant as sources of new active molecules, the anthelmintic activities of the essential oils (EOs) obtained from either Zanthoxylum zanthoxyloides seeds or Newbouldia laevis leaves were evaluated against Strongyloides ratti by analyzing the results of two in vitro bioassays. These two plants and their tested parts were retained after an ethnopharmacology survey that confirmed their use by small-scale farmers for treatment of small ruminants affected by digestive helminths. The plants were harvested in Benin, and their EO were obtained by hydrodistillation. The EO yield of extraction was 0.65% (w/w) of for Z. zanthoxyloides seeds and 0.05% (w/w) for N. laevis. The chemical compositions of the two EOs were analyzed by gas chromatography coupled with mass spectrometry. The major constituents of the EO from Z. zanthoxyloides consisted of the following compounds: -terpinene (18 %), undecane (15 %), valencene (8.3 %), decanal (8.3 %), and 3-carene (6.7 %). In contrast, the major constituents of the EO from N. laevis leaves consisted of the following compounds: -caryophyllene (36 %) and eugenol (5.8 %). An egg-hatching inhibition (EHI) assay was developed and a larval migration inhibition assay was used on S. ratti to examine the effects of the EOs and to evidence their inhibitory concentrations (IC(50) and IC(90)) values on this nematode. Furthermore, the toxicity of the two EOs on Vero cell line was evaluated. When tested on S. ratti egg hatching, the two EOs resulted in similar IC(50) values (19.5 and 18.2 g/ml for Z. zanthoxyloides and N. laevis, respectively), which were about sevenfold higher than that of the control (thiabendazole, IC(50)=2.5 g/ml). Larval migration was inhibited at similar concentrations for: Z. zanthoxyloides (IC(50)=46 g/ml), N. laevis (IC(50)=51 g/ml), and the control [levamisole (IC(50)=36 g/ml)]. No cytotoxicity was found on Vero cells because both EOs had IC(50) values higher than 50 g/ml. Therefore, we have concluded that the EOs from two plants, used in folk medicine, may contain compounds with anthelmintic activity and could be used as improved traditional medicines or, at least, as food additives in a combined treatment for the control of helminth infections.

Sisley BM et al. (1987) Parasite Immunol "Associations between clinical disease, circulating antibodies and C1q-binding immune complexes in human onchocerciasis."

el Sheikh H, O'Day J, Luty AJ, Braga M, Mackenzie CD, Steward MW, Sisley BM, Williams JF

[Parasite Immunol, 1987]

Onchocerciasis is a disease where often there are high levels of serum antibodies and high parasitic loads. The role of immune complexes in the development of the disease is investigated here by studying non-specific and Onchocerca volvulus specific immune complex levels, as well as the antibody concentrations, in the sera of 372 people living in either Southern (199) or Northern (173) Sudan; sera from Sudanese individuals (31) and Caucasians (21) living outside the onchocerciasis endemic area were also tested. The levels of non-specific immune complexes (NS-IC) in these sera were measured by a solid phase radio-immunoassay and those of O. volvulus-specific immune complexes (OV-IC) by an assay measuring antibody-excess complexes using C1q-coated plates. The concentrations of O. volvulus IgG antibodies were measured by ELISA. Immune complex and antibody levels of the serum donors were compared with regard to their clinical status due to onchocerciasis. These clinical changes were classified according to onchocercal lesions related to either the active destruction of microfilariae (acute changes), or the long term tissue alterations (chronic changes). Data was analysed using the Odds Ratio method. A negative association between microfilarial load and immune complex level was found, with the higher levels of OV-IC present in patients with the lower levels of dermal microfilariae (i.e., less than 10 mf/mg). Significant associations between immune complex levels and the severity of onchocercal disease were also found. Levels of OV-IC specific immune complexes were higher in infected individuals carrying dermal onchocercal lesions than in those without such clinical changes; there was no apparent relationship between these levels and the presence of ocular lesions. OV-IC levels varied considerably within each age group and from age to age. A weak positive association was detected between microfilarial load and parasite-specific IgG antibody concentration in the sera. On average younger individuals (less than 25 years) had the higher antibody levels with a gradual reduction in mean concentrations with age. The significance of these serological findings in terms of the pathogenesis of onchocerciasis is discussed.

Satou T et al. (2002) Vet Parasitol "Assay of nematocidal activity of isoquinoline alkaloids using third-stage larvae of Strongyloides ratti and S. venezuelensis."

Tada I, Satou T, Matsuhashi R, Koike K, Koga M, Nikaido T

[Vet Parasitol, 2002]

We examined the effects of isoquinoline alkaloids in vitro in an effort to identify a treatment for Strongyloides stercoralis larva migrans in humans. Infective third-stage larvae of S. ratti and S. venezuelensis were used as model nematodes for S. stercoralis. Nematocidal activity was evaluated by the 50% paralysis concentration (PC(50)). Most of the tested isoquinoline alkaloids had activity for S. ratti and S. venezuelensis. We then evaluated in vitro cytotoxicity, which was the 50% inhibition concentration (IC(50)) of the compounds using HL60 tissue-culture cells. Three of the compounds (protopine, D-corydaline, and L-stylopine) which exhibited strong nematocidal activity, showed little cytotoxicity. In addition, we examined the relationship between nematocidal activity and cytotoxicity using the PC(50)/IC(50) ratio. A ratio equivalent to or lower than that calculated for the currently prescribed strongyloidosis treatments, ivermectin, albendazole and thiabendazole, was observed for allocryptopine, protopine, dehydrocorydaline, D-corydaline, L-stylopine, and papaverine. In contrast, the PC(50)/IC(50) ratios for protopine, D-corydaline, and L-stylopine were substantially more favorable. Therefore, protopine, D-corydaline, and L-stylopine were identified as potential effective treatments for strongyloidosis.

Liu M et al. (2018) Int J Parasitol "Bioassay-guided isolation of three anthelmintic compounds from Warburgia ugandensis Sprague subspecies ugandensis, and the mechanism of action of polygodial."

Liu M, Braeckman BP, Dhondt I, Luyten W, Kipanga P, Mai AH, De Borggraeve W

[Int J Parasitol, 2018]

Parasitic helminths continue to pose problems in human and veterinary medicine, as well as in agriculture. Resistance to current anthelmintics has prompted the search for new drugs. Anthelmintic metabolites from medicinal plants could be good anthelmintic drug candidates. However, the compounds active against nematodes have not been identified in most medicinal plants with anthelmintic activity. In this study, we aimed to identify the active compounds against helminths in Warburgia ugandensis Sprague subspecies ugandensis (Canellaceae) and study the underlying mechanism of action. A bioassay-guided isolation of anthelmintic compounds from the plant was performed using a Caenorhabditis elegans test model with a WMicrotracker instrument to monitor motility. Three active compounds were purified and identified by nuclear magnetic resonance and high resolution MS: warburganal (IC₅₀: 28.2 +/- 8.6 M), polygodial (IC₅₀: 13.1 +/- 5.3 M) and alpha-linolenic acid (ALA, IC₅₀: 70.1 +/- 17.5 M). A checkerboard assay for warburganal and ALA as well as polygodial and ALA showed a fractional inhibitory concentration index of 0.41 and 0.37, respectively, suggesting that polygodial and ALA, as well as warburganal and ALA, have a synergistic effect against nematodes. A preliminary structure-activity relationship study for polygodial showed that the ,-unsaturated 1,4-dialdehyde structural motif is essential for the potent activity. None of a panel of C. elegans mutant strains, resistant against major anthelmintic drug classes, showed significant resistance to polygodial, implying that polygodial may block C. elegans motility through a mechanism which differs from that of currently marketed drugs. Further measurements showed that polygodial inhibits mitochondrial ATP synthesis of C. elegans in a dose-dependent manner (IC₅₀: 1.8 +/- 1.0 M). Therefore, we believe that the underlying mechanism of action of polygodial is probably inhibition of mitochondrial ATP synthesis. In conclusion, polygodial could be a promising anthelmintic drug candidate worth considering for further development.