Novel Nematode-Killing Protein-1 (Nkp-1) from a Marine Epiphytic Bacterium Pseudoalteromonas tunicata

Drug resistance among parasitic nematodes has resulted in an urgent need for the development of new therapies. However, the high re-discovery rate of anti-nematode compounds from terrestrial environments necessitates a new repository for future drug research. Marine epiphytes are hypothesised to produce nematicidal compounds as a defence against bacterivorous predators, thus representing a promising yet underexplored source for anti-nematode drug discovery. The marine epiphytic bacterium Pseudoalteromonas tunicata is known to produce several bioactive compounds. Screening heterologously expressed genomic libraries of P. tunicata against the nematode Caenorhabditis elegans, identified as an E. coli clone (HG8), shows fast-killing activity. Here we show that clone HG8 produces a novel nematode-killing protein-1 (Nkp-1) harbouring a predicted carbohydrate-binding domain with weak homology to known bacterial pore-forming toxins. We found bacteria expressing Nkp-1 were able to colonise the C. elegans intestine, with exposure to both live bacteria and protein extracts resulting in physical damage and necrosis, leading to nematode death within 24 h of exposure. Furthermore, this study revealed C. elegans dar (deformed anal region) and internal hatching may act as a nematode defence strategy against Nkp-1 toxicity. The characterisation of this novel protein and putative mode of action not only contributes to the development of novel anti-nematode applications in the future but reaffirms the potential of marine epiphytic bacteria as a new source of novel biomolecules.

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Nematode ligand-gated chloride channels: an appraisal of their involvement in macrocyclic lactone resistance and prospects for developing molecular markers

Parasitology ◽

10.1017/s0031182007000042 ◽

2007 ◽

Vol 134 (8) ◽

pp. 1111-1121 ◽

Cited By ~ 51

Author(s):

S. McCAVERA ◽

T. K. WALSH ◽

A. J. WOLSTENHOLME

Keyword(s):

Haemonchus Contortus ◽

Chloride Channels ◽

Macrocyclic Lactone ◽

Parasitic Nematodes ◽

C Elegans ◽

Molecular Tests ◽

Cooperia Oncophora ◽

Macrocyclic Lactone Resistance ◽

High Level ◽

Laboratory Models

SUMMARYLigand-gated chloride channels, including the glutamate-(GluCl) and GABA-gated channels, are the targets of the macrocyclic lactone (ML) family of anthelmintics. Changes in the sequence and expression of these channels can cause resistance to the ML in laboratory models, such as Caenorhabditis elegans and Drosophila melanogaster. Mutations in multiple GluCl subunit genes are required for high-level ML resistance in C. elegans, and this can be influenced by additional mutations in gap junction and amphid genes. Parasitic nematodes have a different complement of channel subunit genes from C. elegans, but a few genes, including avr-14, are widely present. A polymorphism in an avr-14 orthologue, which makes the subunit less sensitive to ivermectin and glutamate, has been identified in Cooperia oncophora, and polymorphisms in several subunits have been reported from resistant isolates of Haemonchus contortus. This has led to suggestions that ML resistance may be polygenic. Possible reasons for this, and its consequences for the development of molecular tests for resistance, are explored.

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The Ditylenchus destructor genome provides new insights into the evolution of plant parasitic nematodes

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.0942 ◽

2016 ◽

Vol 283 (1835) ◽

pp. 20160942 ◽

Cited By ~ 14

Author(s):

Jinshui Zheng ◽

Donghai Peng ◽

Ling Chen ◽

Hualin Liu ◽

Feng Chen ◽

...

Keyword(s):

Evolutionary History ◽

Evolutionary Process ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Free Living ◽

C Elegans ◽

Free Living Nematode ◽

Plant Nematode ◽

Ditylenchus Destructor ◽

Plant Parasitic

Plant-parasitic nematodes were found in 4 of the 12 clades of phylum Nematoda. These nematodes in different clades may have originated independently from their free-living fungivorous ancestors. However, the exact evolutionary process of these parasites is unclear. Here, we sequenced the genome sequence of a migratory plant nematode, Ditylenchus destructor . We performed comparative genomics among the free-living nematode, Caenorhabditis elegans and all the plant nematodes with genome sequences available. We found that, compared with C. elegans , the core developmental control processes underwent heavy reduction, though most signal transduction pathways were conserved. We also found D. destructor contained more homologies of the key genes in the above processes than the other plant nematodes. We suggest that Ditylenchus spp. may be an intermediate evolutionary history stage from free-living nematodes that feed on fungi to obligate plant-parasitic nematodes. Based on the facts that D. destructor can feed on fungi and has a relatively short life cycle, and that it has similar features to both C. elegans and sedentary plant-parasitic nematodes from clade 12, we propose it as a new model to study the biology, biocontrol of plant nematodes and the interaction between nematodes and plants.

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Natural variation in Caenorhabditis elegans responses to the anthelmintic emodepside

10.1101/2021.01.05.425329 ◽

2021 ◽

Author(s):

Janneke Wit ◽

Steffen R. Hahnel ◽

Briana C. Rodriguez ◽

Erik Andersen

Keyword(s):

Caenorhabditis Elegans ◽

Mode Of Action ◽

Natural Variation ◽

Treatment Strategies ◽

Parasitic Nematodes ◽

Anthelmintic Drug ◽

C Elegans ◽

Hormetic Effect ◽

Filarial Nematodes

Treatment of parasitic nematode infections depends primarily on the use of anthelmintics. However, this drug arsenal is limited, and resistance against most anthelmintics is widespread. Emodepside is a new anthelmintic drug effective against gastrointestinal and filarial nematodes. Nematodes that are resistant to other anthelmintic drug classes are susceptible to emodepside, indicating that the emodepside mode of action is distinct from previous anthelmintics. The laboratory-adapted Caenorhabditis elegans strain N2 is sensitive to emodepside, and genetic selection and in vitro experiments implicated slo-1, a BK potassium channel gene, in emodepside mode of action. In an effort to understand how natural populations will respond to emodepside, we measured brood sizes and developmental rates of wild C. elegans strains after exposure to the drug and found natural variation across the species. Some variation in emodepside responses can be explained by natural differences in slo-1. This result suggests that other genes in addition to slo-1 underlie emodepside resistance in wild C. elegans strains. Additionally, all assayed strains have higher offspring production in low concentrations of emodepside (a hormetic effect), which could impact treatment strategies. We find that natural variation affects emodepside sensitivity, supporting the suitability of C. elegans as a model system to study emodepside responses across parasitic nematodes.

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In Vitro Efficacy of Aqueous and Methanol Extract of Cassia siamea Against the Motility of Caenorhabditis elegans

Tropical Life Sciences Research ◽

10.21315/tlsr2020.31.3.10 ◽

2020 ◽

Vol 31 (3) ◽

pp. 145-159

Author(s):

Haladu Ali Gagman ◽

Nik Ahmad Irwan Izzauddin Nik Him ◽

Hamdan Ahmad ◽

Shaida Fariza Sulaiman ◽

Rahmad Zakaria ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Methanol Extract ◽

Anthelmintic Resistance ◽

Gastrointestinal Nematode ◽

Parasitic Nematodes ◽

Cassia Siamea ◽

Methanol Extracts ◽

C Elegans ◽

Significant Difference

Gastrointestinal nematode infections can cause great losses in revenue due to decrease livestock production and animal death. The use of anthelmintic to control gastrointestinal nematode put a selection pressure on nematode populations which led to emergence of anthelmintic resistance. Because of that, this study was carried out to investigate the efficacy of aqueous and methanol extract of Cassia siamea against the motility of C. elegans Bristol N2 and C. elegans DA1316. Caenorhabditis elegans Bristol N2 is a susceptible strain and C. elegans DA1316 is an ivermectin resistant strain. In vitro bioassay of various concentrations of (0.2, 0.6, 0.8, 1.0 and 2.0 mg mL–1) aqueous and methanol extracts of C. siamea was conducted against the motility of L4 larvae of C. elegans Bristol N2 and C. elegans DA1316. The L4 larvae were treated with 0.02 μg mL–1 of ivermectin served as positive control while those in M9 solution served as negative control. The activity of the extracts was observed after 24 h and 48 h. A significant difference was recorded in the extract performance compared to control at (P < 0.001) after 48 h against the motility of the larvae of both strains. The methanol extracts inhibited the motility of C. elegans Bristol N2 by 86.7% as well as DA1316 up to 84.9% at 2.0 mg mL–1 after 48 h. The methanol extract was more efficient than aqueous extract (P < 0.05) against the motility of both strains of C. elegans. Cassia siamea may be used as a natural source of lead compounds for the development of alternative anthelmintic against parasitic nematodes as well ivermectin resistant strains of nematodes.

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Protein-observed 19F NMR of LecA from Pseudomonas aeruginosa

Glycobiology ◽

10.1093/glycob/cwaa057 ◽

2020 ◽

Author(s):

Elena Shanina ◽

Eike Siebs ◽

Hengxi Zhang ◽

Daniel Varón Silva ◽

Ines Joachim ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Carbohydrate Binding ◽

Binding Region ◽

Chronic Infections ◽

Nmr Titration ◽

Affinity Ligands ◽

Natural Ligands ◽

Future Drug

Abstract The carbohydrate-binding protein LecA (PA-IL) from Pseudomonas aeruginosa plays an important role in the formation of biofilms in chronic infections. Development of inhibitors to disrupt LecA-mediated biofilms is desired but it is limited to carbohydrate-based ligands. Moreover, discovery of drug-like ligands for LecA is challenging because of its weak affinities. Therefore, we established a protein-observed 19F (PrOF) nuclear magnetic resonance (NMR) to probe ligand binding to LecA. LecA was labeled with 5-fluoroindole to incorporate 5-fluorotryptophanes and the resonances were assigned by site-directed mutagenesis. This incorporation did not disrupt LecA preference for natural ligands, Ca2+ and d-galactose. Following NMR perturbation of W42, which is located in the carbohydrate-binding region of LecA, allowed to monitor binding of low-affinity ligands such as N-acetyl d-galactosamine (d-GalNAc, Kd = 780 ± 97 μM). Moreover, PrOF NMR titration with glycomimetic of LecA p-nitrophenyl β-d-galactoside (pNPGal, Kd = 54 ± 6 μM) demonstrated a 6-fold improved binding of d-Gal proving this approach to be valuable for ligand design in future drug discovery campaigns that aim to generate inhibitors of LecA.

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Small RNAs in parasitic nematodes – forms and functions

Parasitology ◽

10.1017/s0031182019001689 ◽

2019 ◽

Vol 147 (8) ◽

pp. 855-864

Author(s):

Collette Britton ◽

Roz Laing ◽

Eileen Devaney

Keyword(s):

Gene Expression ◽

Small Rna ◽

Small Rnas ◽

Target Genes ◽

Parasitic Nematodes ◽

Small Rna Sequencing ◽

Small Interfering Rnas ◽

Rna Sequences ◽

C Elegans

AbstractSmall RNAs are important regulators of gene expression. They were first identified in Caenorhabditis elegans, but it is now apparent that the main small RNA silencing pathways are functionally conserved across diverse organisms. Availability of genome data for an increasing number of parasitic nematodes has enabled bioinformatic identification of small RNA sequences. Expression of these in different lifecycle stages is revealed by small RNA sequencing and microarray analysis. In this review we describe what is known of the three main small RNA classes in parasitic nematodes – microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs) and small interfering RNAs (siRNAs) – and their proposed functions. miRNAs regulate development in C. elegans and the temporal expression of parasitic nematode miRNAs suggest modulation of target gene levels as parasites develop within the host. miRNAs are also present in extracellular vesicles released by nematodes in vitro, and in plasma from infected hosts, suggesting potential regulation of host gene expression. Roles of piRNAs and siRNAs in suppressing target genes, including transposable elements, are also reviewed. Recent successes in RNAi-mediated gene silencing, and application of small RNA inhibitors and mimics will continue to advance understanding of small RNA functions within the parasite and at the host–parasite interface.

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RNA interference in Caenorhabditis elegans: Uptake, mechanism, and regulation

Parasitology ◽

10.1017/s0031182011001788 ◽

2011 ◽

Vol 139 (5) ◽

pp. 560-573 ◽

Cited By ~ 35

Author(s):

JIMMY J. ZHUANG ◽

CRAIG P. HUNTER

Keyword(s):

Rna Interference ◽

Genetic Analysis ◽

Large Scale ◽

Parasitic Nematodes ◽

Loss Of Function ◽

Uptake Mechanism ◽

Delivery Methods ◽

C Elegans ◽

Systemic Rnai ◽

Powerful Research Tool

SUMMARYRNA interference (RNAi) is a powerful research tool that has enabled molecular insights into gene activity, pathway analysis, partial loss-of-function phenotypes, and large-scale genomic discovery of gene function. While RNAi works extremely well in the non-parasitic nematode C. elegans, it is also especially useful in organisms that lack facile genetic analysis. Extensive genetic analysis of the mechanisms, delivery and regulation of RNAi in C. elegans has provided mechanistic and phenomenological insights into why RNAi is so effective in this species. These insights are useful for the testing and development of RNAi in other nematodes, including parasitic nematodes where more effective RNAi would be extremely useful. Here, we review the current advances in C. elegans for RNA delivery methods, regulation of cell autonomous and systemic RNAi phenomena, and implications of enhanced RNAi mutants. These discussions, with a focus on mechanism and cross-species application, provide new perspectives for optimizing RNAi in other species.

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Molecular cloning and life stage expression pattern of a new acetylcholinesterase gene from the plant-parasitic nematode Meloidogyne incognita

Nematology ◽

10.1163/156854103767139707 ◽

2003 ◽

Vol 5 (2) ◽

pp. 213-217 ◽

Cited By ~ 8

Author(s):

Jean-Baptiste Laffaire ◽

Marie-Noëlle Rosso ◽

Stéphanie Jaubert ◽

Pierre Abad

Keyword(s):

Meloidogyne Incognita ◽

Life Stage ◽

Distinct Group ◽

Catalytic Triad ◽

Pcr Analysis ◽

Parasitic Nematodes ◽

Reading Frame ◽

C Elegans ◽

Second Stage ◽

Before And After

AbstractA new cDNA, named Mi-ace-2, encoding an acetylcholinesterase, was isolated from Meloidogyne incognita. The full-length cDNA, carrying the trans-spliced SL1 leader sequence, was 2122 bp long with an open reading frame of 2058 bp. The predicted protein shared 32.3% identity with the previously identified MI ACHE and 49.1% identity with the C. elegans ACE-2. The conserved motifs involved in the catalytic triad, the choline binding site and 11 aromatic residues lining the catalytic gorge were present in the MI-ACE-2 deduced protein. RT-PCR analysis showed that Mi-ace-2 is transcribed in second stage juveniles before and after hatching, in females and in males. Phylogenetic analysis showed that MI-ACE-2 and ACE-2 were clustered in a distinct group closely related to the acetylcholinesterases secreted by animal-parasitic nematodes.

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Activation of hatching in diapaused and quiescent Globodera pallida

Parasitology ◽

10.1017/s0031182012001874 ◽

2012 ◽

Vol 140 (4) ◽

pp. 445-454 ◽

Cited By ~ 9

Author(s):

JUAN E. PALOMARES-RIUS ◽

JOHN T. JONES ◽

PETER J. COCK ◽

PABLO CASTILLO ◽

VIVIAN C. BLOK

Keyword(s):

Bursaphelenchus Xylophilus ◽

Globodera Pallida ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Cyst Nematodes ◽

Term Survival ◽

C Elegans ◽

Dauer Formation ◽

Dorsal Gland

SUMMARYThe potato cyst nematodes (PCN) Globodera pallida and G. rostochiensis are major pests of potatoes. The G. pallida (and G. rostochiensis) life cycle includes both diapause and quiescent stages. Nematodes in dormancy (diapause or quiescent) are adapted for long-term survival and are more resistant to nematicides. This study analysed the mechanisms underlying diapause and quiescence. The effects of several compounds (8Br-cGMP, oxotremorine and atropine) on the activation of hatching were studied. The measurements of some morphometric parameters in diapaused and quiescent eggs after exposure to PRD revealed differences in dorsal gland length, subventral gland length and dorsal gland nucleolus. In addition, the expression of 2 effectors (IVg9 and cellulase) was not induced in diapaused eggs in water or PRD, while expression was slightly induced in quiescent eggs. Finally, we performed a comparative study to identify orthologues of C. elegans diapause related genes in plant-parasitic nematodes (G. pallida, Meloidogyne incognita, M. hapla and Bursaphelenchus xylophilus). This analysis suggested that it was not possible to identify G. pallida orthologues of the majority of C. elegans genes involved in the control of dauer formation. All these data suggest that G. pallida may use different mechanisms to C. elegans in regulating the survival stage.

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The use of Caenorhabditis elegans in parasitic nematode research

Parasitology ◽

10.1017/s003118200400647x ◽

2004 ◽

Vol 128 (S1) ◽

pp. S49-S70 ◽

Cited By ~ 39

Author(s):

J. S. GILLEARD

Keyword(s):

Caenorhabditis Elegans ◽

Parasitic Nematode ◽

Expression System ◽

Nematode Species ◽

Current Status ◽

Evolutionary Development ◽

Parasitic Nematodes ◽

Free Living ◽

C Elegans ◽

Free Living Nematode

There is increasing interest in the use of the free-living nematode Caenorhabditis elegans as a tool for parasitic nematode research and there are now a number of compelling examples of its successful application. C. elegans has the potential to become a standard tool for molecular helminthology researchers, just as yeast is routinely used by molecular biologists to study vertebrate biology. However, in order to exploit C. elegans in a meaningful manner, we need a detailed understanding of the extent to which different aspects of C. elegans biology have been conserved with particular groups of parasitic nematodes. This review first considers the current state of knowledge regarding the conservation of genome organisation across the nematode phylum and then discusses some recent evolutionary development studies in free-living nematodes. The aim is to provide some important concepts that are relevant to the extrapolation of information from C. elegans to parasitic nematodes and also to the interpretation of experiments that use C. elegans as a surrogate expression system. In general, examples have been specifically chosen because they highlight the importance of careful experimentation and interpretation of data. Consequently, the focus is on the differences that have been found between nematode species rather than the similarities. Finally, there is a detailed discussion of the current status of C. elegans as a heterologous expression system to study parasite gene function and regulation using successful examples from the literature.

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