scholarly journals Genomes: Programmed DNA Elimination in a Parasitic Nematode

2020 ◽  
Vol 30 (17) ◽  
pp. R994-R996
Author(s):  
Kazufumi Mochizuki
Keyword(s):  
Parasitic Nematode ◽  
Dna Elimination

scholarly journals Comprehensive Chromosome End Remodeling During Programmed DNA Elimination

2020 ◽  
Author(s):  
Jianbin Wang ◽  
Giovana M.B. Veronezi ◽  
Yuanyuan Kang ◽  
Maxim Zagoskin ◽  
Eileen T. O’Toole ◽  
...  
Keyword(s):  
Parasitic Nematode ◽  
De Novo ◽  
Dna Breaks ◽  
Chromosome Conformation ◽  
Dna Elimination ◽  
Chromosomal Breaks ◽  
Long Read ◽  
Somatic Genome ◽  
Membrane Bound ◽  
Chromosome Fusions

AbstractGermline and somatic genomes are typically the same in a multicellular organism. However, in some organisms including the parasitic nematode Ascaris, programmed DNA elimination leads to a reduced somatic genome compared to germline cells. Previous work on the parasitic nematode Ascaris demonstrated that programmed DNA elimination encompasses high fidelity chromosomal breaks at specific genome locations and loss of specific genome sequences including a major tandem repeat of 120 bp and ~1,000 germline-expressed genes. However, the precise chromosomal locations of the 120 bp repeats, the breaks regions, and the eliminated genes remained unknown. Here, we used PacBio long-read sequencing and chromosome conformation capture (Hi-C) to obtain fully assembled chromosomes of Ascaris germline and somatic genomes, enabling a complete chromosomal view of DNA elimination. Surprisingly, we found that all 24 germline chromosomes undergo comprehensive chromosome end remodeling with DNA breaks in their subtelomeric regions and loss of distal sequences including the telomeres at both chromosome ends. All new Ascaris somatic chromosome ends are recapped by de novo telomere healing. We provide an ultrastructural analysis of DNA elimination and show that Ascaris eliminated DNA is incorporated into many double membrane-bound structures, similar to micronuclei, during telophase of a DNA elimination mitosis. These micronuclei undergo dynamic changes including loss of active histone marks and localize to the cytoplasm following daughter nuclei formation and cytokinesis where they form autophagosomes. Comparative analysis of nematode chromosomes suggests that germline chromosome fusions occurred forming Ascaris sex chromosomes that become independent chromosomes following DNA elimination breaks in somatic cells. These studies provide the first chromosomal view and define novel features and functions of metazoan programmed DNA elimination.

scholarly journals Integrative Taxonomy and Molecular Phylogeny of the Plant-Parasitic Nematode Genus Paratylenchus (Nematoda: Paratylenchinae): Linking Species with Molecular Barcodes

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 408
Author(s):  
Phougeishangbam Rolish Singh ◽  
Gerrit Karssen ◽  
Marjolein Couvreur ◽  
Sergei A. Subbotin ◽  
Wim Bert
Keyword(s):  
18S Rrna ◽  
Parasitic Nematode ◽  
Integrative Taxonomy ◽  
Coi Gene ◽  
Integrated Analysis ◽  
Gene Sequences ◽  
Unknown Species ◽  
New Gene ◽  
First Time ◽  
Plant Parasitic

Pin nematodes of the genus Paratylenchus are obligate ectoparasites of a wide variety of plants that are distributed worldwide. In this study, individual morphologically vouchered nematode specimens of fourteen Paratylenchus species, including P. aculentus, P. elachistus, P. goodeyi, P. holdemani, P. idalimus, P. microdorus, P. nanus, P. neoamblycephalus, P. straeleni and P. veruculatus, are unequivocally linked to the D2-D3 of 28S, ITS, 18S rRNA and COI gene sequences. Combined with scanning electron microscopy and a molecular analysis of an additional nine known and thirteen unknown species originating from diverse geographic regions, a total of 92 D2-D3 of 28S, 41 ITS, 57 18S rRNA and 111 COI new gene sequences are presented. Paratylenchus elachistus, P. holdemani and P. neoamblycephalus are recorded for the first time in Belgium and P. idalimus for the first time in Europe. Paratylenchus is an excellent example of an incredibly diverse yet morphologically minimalistic plant-parasitic genus, and this study provides an integrated analysis of all available data, including coalescence-based molecular species delimitation, resulting in an updated Paratylenchus phylogeny and the corrective reassignment of 18 D2-D3 of 28S, 3 ITS, 3 18S rRNA and 25 COI gene sequences that were previously unidentified or incorrectly classified.

scholarly journals A survey of the kinome pharmacopeia reveals multiple scaffolds and targets for the development of novel anthelmintics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica Knox ◽  
Nicolas Joly ◽  
Edmond M. Linossi ◽  
José A. Carmona-Negrón ◽  
Natalia Jura ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Developmental Delay ◽  
Small Molecule ◽  
Parasitic Nematode ◽  
Kinase Inhibitor ◽  
Binding Pocket ◽  
Drug Binding ◽  
Nematode Infection ◽  
Selective Inhibitors ◽  
C Elegans

AbstractOver one billion people are currently infected with a parasitic nematode. Symptoms can include anemia, malnutrition, developmental delay, and in severe cases, death. Resistance is emerging to the anthelmintics currently used to treat nematode infection, prompting the need to develop new anthelmintics. Towards this end, we identified a set of kinases that may be targeted in a nematode-selective manner. We first screened 2040 inhibitors of vertebrate kinases for those that impair the model nematode Caenorhabditis elegans. By determining whether the terminal phenotype induced by each kinase inhibitor matched that of the predicted target mutant in C. elegans, we identified 17 druggable nematode kinase targets. Of these, we found that nematode EGFR, MEK1, and PLK1 kinases have diverged from vertebrates within their drug-binding pocket. For each of these targets, we identified small molecule scaffolds that may be further modified to develop nematode-selective inhibitors. Nematode EGFR, MEK1, and PLK1 therefore represent key targets for the development of new anthelmintic medicines.

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