The genome ofStrongyloidesspp. gives insights into protein families with a putative role in nematode parasitism

SUMMARYParasitic nematodes are important and abundant parasites adapted to live a parasitic lifestyle, with these adaptations all aimed at facilitating their survival and reproduction in their hosts. The recently sequenced genomes of fourStrongyloidesspecies, gastrointestinal parasites of humans and other animals, alongside transcriptomic and proteomic analysis of free-living and parasitic stages of their life cycles have revealed a number of protein families with a putative role in their parasitism. Many of these protein families have also been associated with parasitism in other parasitic nematode species, suggesting that these proteins may play a fundamental role in nematode parasitism more generally. Here, we review key protein families that have a putative role inStrongyloides’ parasitism – acetylcholinesterases, astacins, aspartic proteases, prolyl oligopeptidases, proteinase inhibitors (trypsin inhibitors and cystatins), SCP/TAPS and transthyretin-like proteins – and the evidence for their key, yet diverse, roles in the parasitic lifestyle.

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On the role of dauer in the adaptation of nematodes to a parasitic lifestyle

Parasites & Vectors ◽

10.1186/s13071-021-04953-6 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Lieke E. Vlaar ◽

Andre Bertran ◽

Mehran Rahimi ◽

Lemeng Dong ◽

Jan E. Kammenga ◽

...

Keyword(s):

Molecular Mechanisms ◽

Meta Analysis ◽

Nematode Species ◽

Life Cycles ◽

Signalling Pathway ◽

Parasitic Nematodes ◽

Wide Range ◽

Free Living Nematode ◽

Parasitic Lifestyle ◽

Dauer Signalling Pathway

AbstractNematodes are presumably the most abundant Metazoa on Earth, and can even be found in some of the most hostile environments of our planet. Various types of hypobiosis evolved to adapt their life cycles to such harsh environmental conditions. The five most distal major clades of the phylum Nematoda (Clades 8–12), formerly referred to as the Secernentea, contain many economically relevant parasitic nematodes. In this group, a special type of hypobiosis, dauer, has evolved. The dauer signalling pathway, which culminates in the biosynthesis of dafachronic acid (DA), is intensively studied in the free-living nematode Caenorhabditis elegans, and it has been hypothesized that the dauer stage may have been a prerequisite for the evolution of a wide range of parasitic lifestyles among other nematode species. Biosynthesis of DA is not specific for hypobiosis, but if it results in exit of the hypobiotic state, it is one of the main criteria to define certain behaviour as dauer. Within Clades 9 and 10, the involvement of DA has been validated experimentally, and dauer is therefore generally accepted to occur in those clades. However, for other clades, such as Clade 12, this has hardly been explored. In this review, we provide clarity on the nomenclature associated with hypobiosis and dauer across different nematological subfields. We discuss evidence for dauer-like stages in Clades 8 to 12 and support this with a meta-analysis of available genomic data. Furthermore, we discuss indications for a simplified dauer signalling pathway in parasitic nematodes. Finally, we zoom in on the host cues that induce exit from the hypobiotic stage and introduce two hypotheses on how these signals might feed into the dauer signalling pathway for plant-parasitic nematodes. With this work, we contribute to the deeper understanding of the molecular mechanisms underlying hypobiosis in parasitic nematodes. Based on this, novel strategies for the control of parasitic nematodes can be developed.

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Isolation of Whole Esophageal Gland Cells from Plant-Parasitic Nematodes for Transcriptome Analyses and Effector Identification

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-05-12-0121-fi ◽

2013 ◽

Vol 26 (1) ◽

pp. 31-35 ◽

Cited By ~ 39

Author(s):

Tom R. Maier ◽

Tarek Hewezi ◽

Jiqing Peng ◽

Thomas J. Baum

Keyword(s):

Parasitic Nematode ◽

Nematode Species ◽

Plant Parasitic Nematode ◽

Read Length ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Gland Cells ◽

Esophageal Gland ◽

Nematode Parasitism ◽

Plant Parasitic

Esophageal glands of plant-parasitic nematodes are highly specialized cells whose gene expression products include secreted effector proteins, which govern nematode parasitism of host plants. Therefore, elucidating the transcriptomes of esophageal glands with the goal of identifying nematode effectors is a promising avenue to understanding nematode parasitism and its evolutionary origins as well as to devising nematode control strategies. We have developed a method to separate and isolate individual esophageal gland cells from multiple species of plant-parasitic nematodes while preserving RNA quality. We have used such isolated gland cells for transcriptome analysis via high-throughput DNA sequencing. This method relies on the differential histochemical staining of the gland cells after homogenization of phytonematode tissues. Total RNA was extracted from whole gland cells isolated from eight different plant-parasitic nematode species. To validate this approach, the isolated RNA from three plant-parasitic nematode species—Globodera rostochiensis, Pratylenchus penetrans, and Radopholus similis—was amplified, gel purified, and used for 454 sequencing. We obtained 456,801 total reads with an average read length of 409 bp. Sequence analyses revealed the presence of homologs of previously known nematode effectors in these libraries, thus validating our approach. These data provide compelling evidence that this technical advance can be used to relatively easily and expediently discover effector repertoires of plant-parasitic nematodes.

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Distribution of ascaridoid nematodes (Nematoda: Chromadorea: Ascaridoidea) in fish from the Barents Sea

Oceanological and Hydrobiological Studies ◽

10.1515/ohs-2018-0014 ◽

2018 ◽

Vol 47 (2) ◽

pp. 128-139 ◽

Cited By ~ 2

Author(s):

Katarzyna Najda ◽

Agnieszka Kijewska ◽

Tomasz Kijewski ◽

Kęstas Plauška ◽

Jerzy Rokicki

Keyword(s):

Barents Sea ◽

Food Preferences ◽

Nematode Species ◽

Body Cavity ◽

Life Cycles ◽

Anisakis Simplex ◽

Parasitic Nematodes ◽

Environmental Preferences ◽

The Barents Sea ◽

The Impact

Abstract The Ascaridoidea are parasites with heteroxenous life cycles. The study shows that fish can be paratenic, intermediate, or final hosts for parasites, and parasitic fauna reflects the feeding behavior of the hosts. Each species of parasites has also different environmental preferences and host specificity. Parasitic nematodes of fish representing Pleuronectidae, Gadidae, Sebastidae, and Macrouridae were studied. Worms were collected separately from different infection sites: stomach, intestine, liver and body cavity. Nematodes were identified using both morphological and molecular methods (PCR-RFLP). Six nematode species were recorded: Anisakis simplex s.s., Contracaecum osculatum A, B, and C. osculatum C (s.s.), Hysterothylacium aduncum and Pseudoterranova bulbosa. Anisakis simplex s.s. was the most numerous nematode species of all catches combined. Differences in parasite species composition were related to the depth and location of sampling areas. In the fish from deep waters, the abundance of A. simplex s.s. decreased compared to fish from shallow waters and P. bulbosa was the dominant species. Ascaridoid species have specific preferences regarding the impact on various internal organs of fish, which is reflected in their abundance. The presence of Ascaridoidea in the Barents Sea is associated with the distribution of hosts and varying food preferences related to the age of fish. The abundance of parasites varied between different host species.

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Susceptible trichostrongyloid species mask presence of benzimidazole-resistant Haemonchus contortus in cattle

Parasites & Vectors ◽

10.1186/s13071-021-04593-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Khalid M. Mohammedsalih ◽

Jürgen Krücken ◽

Ahmed Bashar ◽

Fathel-Rahman Juma ◽

Abdalhakaim A. H. Abdalmalaik ◽

...

Keyword(s):

Haemonchus Contortus ◽

Epidemiological Data ◽

Nematode Species ◽

Parasitic Nematodes ◽

Molecular Approaches ◽

Tubulin Genes ◽

Faecal Egg Count ◽

Third Stage ◽

Before And After ◽

Β Tubulin

Abstract Background Benzimidazole (BZ) anthelmintics are widely used to control infections with parasitic nematodes, but BZ resistance is an emerging threat among several nematode species infecting humans and animals. In Sudan, BZ-resistant Haemonchus contortus populations were recently reported in goats in South Darfur State. The objective of this study was to collect data regarding the situation of BZ resistance in cattle parasitic nematodes in South Darfur using phenotypic and molecular approaches, besides providing some epidemiological data on nematodes in cattle. Methods The faecal egg count reduction test and the egg hatch test (EHT) were used to evaluate benzimidazole efficacy in cattle nematodes in five South Darfur study areas: Beleil, Kass, Nyala, Rehed Al-Birdi and Tulus. Genomic DNA was extracted from pools of third-stage larvae (L3) (n = 40) during trials, before and after treatment, and pools of adult male Haemonchus spp. (n = 18) from abattoirs. The polymorphisms F167Y, E198A and F200Y in isotype 1 β-tubulin genes of H. contortus and H. placei were analysed using Sanger and pyrosequencing. Results Prevalence of gastro-intestinal helminths in cattle was 71% (313/443). Reduced albendazole faecal egg count reduction efficacy was detected in three study areas: Nyala (93.7%), Rehed Al-Birdi (89.7%) and Tulus (88.2%). In the EHT, EC50 values of these study areas ranged between 0.032 and 0.037 µg/ml thiabendazole. Genus-specific PCRs detected the genera Haemonchus, Trichostrongylus and Cooperia in L3 samples collected after albendazole treatment. Sanger sequencing followed by pyrosequencing assays did not detect elevated frequencies of known BZ resistance-associated alleles in codon F167Y, E198A and F200Y in isotype 1 β-tubulin gene of H. placei (≤ 11.38%). However, polymorphisms were detected in H. contortus and in samples with mixed infections with H. contortus and H. placei at codon 198, including E198L (16/58), E198V (2/58) and potentially E198Stop (1/58). All pooled L3 samples post-albendazole treatment (n = 13) were identified as H. contortus with an E198L substitution at codon 198. Conclusions To the knowledge of the authors, this is the first report of reduced albendazole efficacy in cattle in Sudan and is the first study describing an E198L substitution in phenotypically BZ-resistant nematodes collected from cattle.

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Description of Mesocriconema ericaceum n. sp. (Nematoda: Criconematidae) and notes on other nematode species discovered in an ericaceous heath bald community in Great Smoky Mountains National Park, USA

Nematology ◽

10.1163/15685411-00003001 ◽

2016 ◽

Vol 18 (8) ◽

pp. 879-903 ◽

Cited By ~ 4

Author(s):

Thomas O. Powers ◽

Peter Mullin ◽

Rebecca Higgins ◽

Timothy Harris ◽

Kirsten S. Powers

Keyword(s):

New Species ◽

National Park ◽

Gulf Coast ◽

Nematode Species ◽

Coi Gene ◽

Parasitic Nematodes ◽

Soil Nematode ◽

Coastal Forests ◽

Great Smoky Mountains ◽

Smoky Mountains

A new species of Mesocriconema and a unique assemblage of plant-parasitic nematodes was discovered in a heath bald atop Brushy Mountain in Great Smoky Mountains National Park. Mesocriconema ericaceum n. sp., a species with males, superficially resembles M. xenoplax. DNA barcoding with the mitochondrial COI gene provided evidence of the new species as a distinct lineage. SEM revealed significant variability in arrangement of labial submedian lobes, plates, and anterior and posterior annuli. Three other nematodes in the family Criconematidae were characterised from the heath bald. Ogma seymouri, when analysed by statistical parsimony, established connections with isolates from north-eastern Atlantic coastal and north-western Pacific coastal wet forests. Criconema loofi has a southern Gulf Coast distribution associated with boggy soils. Criconema cf. acriculum is known from northern coastal forests of California. Understanding linkages between these species and their distribution may lead to the broader development of a terrestrial soil nematode biogeography.

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Prospects of Using High-Throughput Proteomics to Underpin the Discovery of Animal Host–Nematode Interactions

Pathogens ◽

10.3390/pathogens10070825 ◽

2021 ◽

Vol 10 (7) ◽

pp. 825

Author(s):

Tao Wang ◽

Robin Gasser

Keyword(s):

Mass Spectrometry ◽

High Throughput ◽

Anthelmintic Resistance ◽

Nematode Species ◽

Economic Losses ◽

Future Research ◽

Parasitic Nematodes ◽

Public Health Burden ◽

Host Parasite Interactions ◽

Host Parasite

Parasitic nematodes impose a significant public health burden, and cause major economic losses to agriculture worldwide. Due to the widespread of anthelmintic resistance and lack of effective vaccines for most nematode species, there is an urgent need to discover novel therapeutic and vaccine targets, informed through an understanding of host–parasite interactions. Proteomics, underpinned by genomics, enables the global characterisation proteins expressed in a particular cell type, tissue and organism, and provides a key to insights at the host–parasite interface using advanced high-throughput mass spectrometry-based proteomic technologies. Here, we (i) review current mass-spectrometry-based proteomic methods, with an emphasis on a high-throughput ‘bottom-up’ approach; (ii) summarise recent progress in the proteomics of parasitic nematodes of animals, with a focus on molecules inferred to be involved in host–parasite interactions; and (iii) discuss future research directions that could enhance our knowledge and understanding of the molecular interplay between nematodes and host animals, in order to work toward new, improved methods for the treatment, diagnosis and control of nematodiases.

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Host suitability of summer cover crops to Meloidogyne arenaria, M. enterolobii, M. incognita and M. javanica

Nematology ◽

10.1163/15685411-bja10122 ◽

2021 ◽

pp. 1-9

Author(s):

Hung X. Bui ◽

Johan A. Desaeger

Keyword(s):

Cover Crops ◽

Nematode Species ◽

Host Suitability ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Root Knot Nematode ◽

Sunn Hemp ◽

Host Status ◽

Susceptible Control ◽

Sorghum Sudangrass

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.

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Insecticidal and Nematicidal Contributions of Mexican Flora in the Search for Safer Biopesticides

Molecules ◽

10.3390/molecules24050897 ◽

2019 ◽

Vol 24 (5) ◽

pp. 897 ◽

Cited By ~ 3

Author(s):

Beatriz Hernández-Carlos ◽

Marcela Gamboa-Angulo

Keyword(s):

Plant Species ◽

Biological Effects ◽

New Products ◽

Sustainable Use ◽

Nematode Species ◽

Insect Species ◽

Parasitic Nematodes ◽

Plant Metabolites ◽

Future Studies ◽

Pest Insects

Plant metabolites have been used for many years to control pests in animals and to protect crops. Here, we reviewed the available literature, looking for the species of Mexican flora for which extracts and metabolites have shown activity against pest insects and parasitic nematodes of agricultural importance, as well as against nematodes that parasitize domestic cattle. From 1996 to 2018, the search for novel and eco-friendly biopesticides has resulted in the identification of 114 species belonging to 36 botanical families of Mexican plants with reported biological effects on 20 insect species and seven nematode species. Most plant species with detected pesticide properties belong to the families Asteraceae, Fabaceae, and Lamiaceae. Eighty-six metabolites have been identified as pesticidal active principles, and most have been terpenoids. Therefore, the continuation and intensification of this area of research is very important to contribute to the generation of new products that will provide alternatives to conventional pesticide agents. In addition, future studies will contribute to the recognition and dissemination of the importance of propagating plant species for their conservation and sustainable use.

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Differentiated effects of parasitic nematodes Phasmarhabditis hermaphrodita on slugs of the genus Deroceras and snails of the genus Arion

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun200553040171 ◽

2005 ◽

Vol 53 (4) ◽

pp. 171-176

Author(s):

Pavlína Šenoldová ◽

Jiří Rotrekl

Keyword(s):

Parasitic Nematode ◽

Nematode Species ◽

Field Conditions ◽

Parasitic Nematodes ◽

The Family ◽

Snail Family ◽

Phasmarhabditis Hermaphrodita ◽

Differentiated Effects

This paper compares efficiency of preparations based on a parasitic nematode species Phasmarhabditis hermaphrodita with a molluscocide containing methiocarb as an effective substance. Parasitic nematodes by the family Agriolimacidae showed a significantly better effect on mortality and reduction of the percentage of damaged plants than the methiocarb-based preparation. Under laboratory and field conditions, the efficiency of parasitic nematodes on the family Agriolimacidae ranged from 84% to 94% and from 81% to 94%, resp., while the percentages of damaged plants were minimal in both cases. The corresponding effects of the methiocarb-based molluscocide were only 35% and 21%, resp. The effect of parasitic P. hermaphrodita nematodes on members of the snail family Arionidae was not demonstrated both under laboratory and field conditons and the mortality was up to 6% with a total defoliation of plants. Under laboratory and field conditions, the mortality of slugs from the genus Arion after the application of methiocarb-based preparation was 53% and 38%, resp. However, the damage of plants was significant and it reached nearly 67% and 60% under laboratory and field conditions, resp.

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First report, morphological and molecular characterization of Xiphinema elongatum and X. pachtaicum (Nematoda, Longidoridae) from Ethiopia

ZooKeys ◽

10.3897/zookeys.483.8629 ◽

2015 ◽

Vol 489 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Gezahegne Damessa ◽

Wim Bert ◽

Frieda Decraemer

Keyword(s):

18S Rdna ◽

Agricultural Research ◽

Nematode Species ◽

Molecular Data ◽

Geographical Information ◽

Parasitic Nematodes ◽

Root Tips ◽

Complex Species ◽

Morphometric Analyses ◽

First Time

A total of six soil samples were collected around rhizosphere of citrus plants during 2010 from Melkassa Agricultural Research Center experimental station, Ethiopia. From these samples two most important ecto-plant parasitic nematodes of the genus Xiphinema were found and analysed. The genus Xiphinema is a large group of the phylum nematoda which constitutes more than 260 species. They are polyphagous root- ectoparasites of many crop plants and some species of this genus cause damage by direct feeding on root tips and transmit nepoviruses. The delimitation and discrimination of two species in the genus is presented, described herein as Xiphinemaelongatum and Xiphinemapachtaicum. Morphological and morphometric data were done using light microscopy and results of both species were fit within the previously described nematode species of Xiphinemaelongatum and Xiphinemapachtaicum. 18S rDNA were analysed using Bayesian inference (BI) method to reconstruct phylogenetic relationships of the studied Xiphinema sp. (KP407872Xiphinemaelongatum and KP407873Xiphinemapachtaicum) with other Xiphinema species. The 18S rDNA sequence of Xiphinemapachtaicum was alike to previously described species from the GenBank but Xiphinemaelongatum exhibited very small levels of nucleotides differences (0.4%) which might be possible intra-specific divergence. Though this region of rDNA has less resolution on complex species, its combination with morphological and morphometric analyses, suggests these species as Xiphinemaelongatum and Xiphinemapachtaicum with the GenBank accession number of KP407872 and KP407873, respectively. Short notes, morphological measurements, illustrations, and molecular data are given to these species. These species are reported for the first time from Ethiopia and it provides new geographical information of these organisms.

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