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Genetics May 1974Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced...
Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced mutants affecting behavior and morphology have been characterized and about one hundred genes have been defined. Mutations in 77 of these alter the movement of the animal. Estimates of the induced mutation frequency of both the visible mutants and X chromosome lethals suggests that, just as in Drosophila, the genetic units in C. elegans are large.
Topics: Animals; Chromosome Mapping; Crosses, Genetic; Female; Genes, Lethal; Genetic Complementation Test; Genetic Linkage; Genetics, Behavioral; Male; Mesylates; Movement; Mutation; Nematoda; Nervous System Physiological Phenomena; Phenotype; Recombination, Genetic; Reproduction; Sex Chromosomes
PubMed: 4366476
DOI: 10.1093/genetics/77.1.71 -
Current Biology : CB Oct 2013
Topics: Animals; Host-Parasite Interactions; Larva; Nematoda; Parasites; Phylogeny
PubMed: 24112976
DOI: 10.1016/j.cub.2013.08.009 -
Parasitology Feb 2015Nematodes are abundant and diverse, and include many parasitic species. Molecular phylogenetic analyses have shown that parasitism of plants and animals has arisen at... (Review)
Review
Nematodes are abundant and diverse, and include many parasitic species. Molecular phylogenetic analyses have shown that parasitism of plants and animals has arisen at least 15 times independently. Extant nematode species also display lifestyles that are proposed to be on the evolutionary trajectory to parasitism. Recent advances have permitted the determination of the genomes and transcriptomes of many nematode species. These new data can be used to further resolve the phylogeny of Nematoda, and identify possible genetic patterns associated with parasitism. Plant-parasitic nematode genomes show evidence of horizontal gene transfer from other members of the rhizosphere, and these genes play important roles in the parasite-host interface. Similar horizontal transfer is not evident in animal parasitic groups. Many nematodes have bacterial symbionts that can be essential for survival. Horizontal transfer from symbionts to the nematode is also common, but its biological importance is unclear. Over 100 nematode species are currently targeted for sequencing, and these data will yield important insights into the biology and evolutionary history of parasitism. It is important that these new technologies are also applied to free-living taxa, so that the pre-parasitic ground state can be inferred, and the novelties associated with parasitism isolated.
Topics: Animals; Bacteria; Biological Evolution; Gene Transfer, Horizontal; Genome, Helminth; Invertebrates; Nematoda; Nematode Infections; Phylogeny; Plants; Symbiosis
PubMed: 24963797
DOI: 10.1017/S0031182014000791 -
Genes Aug 2021Parasitic nematodes infecting humans and animals are widely distributed in marine and terrestrial environments, causing considerable morbidity and mortality globally...
Parasitic nematodes infecting humans and animals are widely distributed in marine and terrestrial environments, causing considerable morbidity and mortality globally [...].
Topics: Animals; Genomics; Metabolomics; Nematoda; Proteomics
PubMed: 34440423
DOI: 10.3390/genes12081250 -
WormBook : the Online Review of C.... Aug 2005The most abundant synapses in the central nervous system of vertebrates are inhibitory synapses that use the neurotransmitter gamma-aminobutyric acid (GABA). GABA is... (Review)
Review
The most abundant synapses in the central nervous system of vertebrates are inhibitory synapses that use the neurotransmitter gamma-aminobutyric acid (GABA). GABA is also an important neurotransmitter in C. elegans; however, in contrast to vertebrates where GABA acts at synapses of the central nervous system, in nematodes GABA acts primarily at neuromuscular synapses. Specifically, GABA acts to relax the body muscles during locomotion and foraging and to contract the enteric muscles during defecation. The importance of this neurotransmitter for basic motor functions of the worm has facilitated the genetic analysis of proteins required for GABA function. Genetic screens have identified the GABA biosynthetic enzyme, the vesicular transporter, inhibitory and excitatory receptors, and a transcription factor required for the differentiation of GABA cell identity. The plasma membrane transporter and other GABA receptors have been identified by molecular criteria.
Topics: Animals; Nematoda; Neurons; Neurotransmitter Agents; gamma-Aminobutyric Acid
PubMed: 18050397
DOI: 10.1895/wormbook.1.14.1 -
The Korean Journal of Parasitology Feb 2015Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and... (Review)
Review
Serine proteases form one of the most important families of enzymes and perform significant functions in a broad range of biological processes, such as intra- and extracellular protein metabolism, digestion, blood coagulation, regulation of development, and fertilization. A number of serine proteases have been identified in parasitic helminths that have putative roles in parasite development and nutrition, host tissues and cell invasion, anticoagulation, and immune evasion. In this review, we described the serine proteases that have been identified in parasitic helminths, including nematodes (Trichinella spiralis, T. pseudospiralis, Trichuris muris, Anisakis simplex, Ascaris suum, Onchocerca volvulus, O. lienalis, Brugia malayi, Ancylostoma caninum, and Steinernema carpocapsae), cestodes (Spirometra mansoni, Echinococcus granulosus, and Schistocephalus solidus), and trematodes (Fasciola hepatica, F. gigantica, and Schistosoma mansoni). Moreover, the possible biological functions of these serine proteases in the endogenous biological phenomena of these parasites and in the host-parasite interaction were also discussed.
Topics: Animals; Cestoda; Host-Parasite Interactions; Life Cycle Stages; Nematoda; Serine Proteases; Trematoda
PubMed: 25748703
DOI: 10.3347/kjp.2015.53.1.1 -
Seminars in Cell & Developmental Biology Oct 2017Differences between sexes of the same species in lifespan and aging rate are widespread. While the proximal and evolutionary causes of aging are well researched, the... (Review)
Review
Differences between sexes of the same species in lifespan and aging rate are widespread. While the proximal and evolutionary causes of aging are well researched, the factors that contribute to sex differences in these traits have been less studied. The striking diversity of nematodes provides ample opportunity to study variation in sex-specific lifespan patterns associated with shifts in life history and mating strategy. Although the plasticity of these sex differences will make it challenging to generalize from invertebrate to vertebrate systems, studies in nematodes have enabled empirical evaluation of predictions regarding the evolution of lifespan. These studies have highlighted how natural and sexual selection can generate divergent patterns of lifespan if the sexes are subject to different rates or sources of mortality, or if trade-offs between complex traits and longevity are resolved differently in each sex. Here, we integrate evidence derived mainly from nematodes that addresses the molecular and evolutionary basis of sex-specific aging and lifespan. Ultimately, we hope to generate a clearer picture of current knowledge in this area, and also highlight the limitations of our understanding.
Topics: Animals; Biological Evolution; Female; Gene Expression Regulation, Developmental; Genetic Variation; Longevity; Male; Nematoda; Phenotype; Reproduction; Selection, Genetic; Sex Characteristics; Sex Factors
PubMed: 28554570
DOI: 10.1016/j.semcdb.2017.05.012 -
Current Biology : CB Oct 2016Nematodes comprise one of the largest phyla in the animal kingdom, both in terms of individual numbers and species diversity. Although only 20,000-30,000 species have...
Nematodes comprise one of the largest phyla in the animal kingdom, both in terms of individual numbers and species diversity. Although only 20,000-30,000 species have been described, it is estimated that the true number ranges between 100,000 and 10 million. Marine, freshwater, and terrestrial species are all widespread, and some nematodes have even been isolated from such inhospitable environments as deserts, hot springs, and polar seas. Some nematode species are parasitic, with either plant or animal hosts; other species are free-living microbivores, scavengers, or predators of insects or other nematodes. Nematodes vary widely in size, from small microbivores that grow no larger than 100 μm to large animal parasites growing to several meters in length. They adopt a variety of reproductive strategies: most species are gonochoristic (i.e., have male and female sexes), but self-fertile hermaphroditic species are not uncommon, and parthenogenetic species are also known. Nematodes belong to the superphylum Ecdysozoa, a clade of moulting animals that also includes arthropods, tardigrades and priapulids. Although nematode fossils are rare, the origin of the nematode phylum is believed to be very ancient, with the divergence from arthropods estimated based on molecular data to have been between 900 and 1,300 Ma.
Topics: Animals; Biological Evolution; Nematoda; Nervous System; Nervous System Physiological Phenomena; Phylogeny
PubMed: 27780068
DOI: 10.1016/j.cub.2016.07.044 -
Current Biology : CB Jun 2012
Review
Topics: Animals; Host-Parasite Interactions; Humans; Insecta; Larva; Nematoda; Symbiosis
PubMed: 22677279
DOI: 10.1016/j.cub.2012.03.047 -
International Journal of Molecular... Jun 2018To successfully invade and infect their host plants, plant parasitic nematodes (PPNs) need to evolve molecular mechanisms to overcome the defense responses from the... (Review)
Review
To successfully invade and infect their host plants, plant parasitic nematodes (PPNs) need to evolve molecular mechanisms to overcome the defense responses from the plants. Nematode-associated molecular patterns (NAMPs), including ascarosides and certain proteins, while instrumental in enabling the infection, can be perceived by the host plants, which then initiate a signaling cascade leading to the induction of basal defense responses. To combat host resistance, some nematodes can inject effectors into the cells of susceptible hosts to reprogram the basal resistance signaling and also modulate the hosts' gene expression patterns to facilitate the establishment of nematode feeding sites (NFSs). In this review, we summarized all the known signaling pathways involved in plant⁻nematode interactions. Specifically, we placed particular focus on the effector proteins from PPNs that mimic the signaling of the defense responses in host plants. Furthermore, we gave an updated overview of the regulation by PPNs of different host defense pathways such as salicylic acid (SA)/jasmonic acid (JA), auxin, and cytokinin and reactive oxygen species (ROS) signaling to facilitate their parasitic successes in plants. This review will enhance the understanding of the molecular signaling pathways involved in both compatible and incompatible plant⁻nematode interactions.
Topics: Animals; Host-Parasite Interactions; Nematoda; Plants; Signal Transduction
PubMed: 29865232
DOI: 10.3390/ijms19061648