Jump to content

Nematode

From Wikipedia, the free encyclopedia
(Redirected fromNematoda)

Nematode
Temporal range:Early Devonian–Recent[1]Possible Cambrian occurrence[2]
Caenorhabditis elegans,
a model species of roundworm
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Subkingdom: Eumetazoa
Clade: ParaHoxozoa
Clade: Bilateria
Clade: Nephrozoa
(unranked): Protostomia
Superphylum: Ecdysozoa
Clade: Nematoida
Phylum: Nematoda
Diesing,1861
Classes

(seetext)

Synonyms
  • NematodesBurmeister,1837
  • Nematoideasensu strictoCobb, 1919
  • NematesCobb, 1919
  • NemataCobb, 1919emend.

Thenematodes(/ˈnɛmətoʊdz/NEM-ə-tohdzorNEEM-;Greek:Νηματώδη;Latin:Nematoda),roundwormsoreelwormsconstitute thephylumNematoda.[3][4]They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding onmicroorganisms,but many species areparasitic.[3]The parasitic worms (helminths) are the cause ofsoil-transmitted helminthiases.

They are taxonomically classified along witharthropods,tardigradesand othermoultinganimalsin thecladeEcdysozoa.Unlike the vaguely similarflatworms,nematodes have a tubulardigestive system,with openings at both ends. Like tardigrades, they have a reduced number ofHox genes,but their sister phylumNematomorphahas kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum.[5]

Nematodespeciescan be difficult to distinguish from one another. Consequently, estimates of the number of nematode species are uncertain. A 2013 survey of animal biodiversity published in themega journalZootaxaputs this figure at over 25,000.[6][7]Estimates of the total number ofextantspecies are subject to even greater variation. A widely referenced article published in 1993 estimated there may be over 1 million species of nematode.[8]A subsequent publication challenged this claim, estimating the figure to be at least 40,000 species.[9]Although the highest estimates (up to 100 million species) have since been deprecated, estimates supported byrarefaction curves,[10][11]together with the use ofDNA barcoding[12]and the increasing acknowledgment of widespreadcryptic speciesamong nematodes,[13]have placed the figure closer to 1 million species.[14]

Nematodes have successfully adapted to nearly everyecosystem:from marine (salt) to fresh water, soils, from the polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual andspeciescounts, and are found in locations as diverse as mountains, deserts, andoceanic trenches.They are found in every part of the Earth'slithosphere,[15]even at great depths, 0.9–3.6 km (3,000–12,000 ft) below the surface of the Earth in gold mines in South Africa.[16][17][18][19][15]They represent 90% of all animals on theocean floor.[20] In total, 4.4 × 1020nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests.[21] Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on Earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems.[21][22] They have been shown to play crucial roles in polar ecosystems.[23][24] The roughly 2,271generaare placed in 256families.[25] The many parasitic forms includepathogensin most plants and animals. A third of the genera occur asparasitesofvertebrates;about 35 nematode species occur in humans.[25]

Etymology

[edit]

The wordnematodecomes from theModern Latincompound ofnemat-'thread' (from Greeknema,genitivenematos'thread', from the stemnein'to spin'; cf.needle) +-odes'like, of the nature of' (cf.-oid).

Taxonomy and systematics

[edit]
See also:List of nematode families
Eophasma jurasicum,a fossilized nematode
Caenorhabditis elegans
Rhabditia
Nippostrongylus brasiliensis
UnidentifiedAnisakidae(Ascaridina:Ascaridoidea)
OxyuridaeThreadworm
SpiruridaeDirofilaria immitis
NematodeSteinernema feltiaewith size comparison 1 EURO coin
NematodeSteinernema feltiaewith size comparison of 1 EURO coin

History

[edit]

In 1758, Linnaeus described some nematode genera (e.g.,Ascaris), then included in theVermes.

The name of the group Nematoda, informally called "nematodes", came fromNematoidea,originally defined byKarl Rudolphi(1808),[26]fromAncient Greekνῆμα (nêma, nêmatos,'thread') and -ειδἠς (-eidēs,'species'). It was treated asfamilyNematodes byBurmeister(1837).[26]

At its origin, the "Nematoidea" erroneously included Nematodes andNematomorpha,attributed by von Siebold (1843). Along withAcanthocephala,Trematoda,andCestoidea,it formed the obsolete groupEntozoa,[27]created by Rudolphi (1808).[28]They were also classed along with Acanthocephala in the obsoletephylumNemathelminthesby Gegenbaur (1859).

In 1861,K. M. Diesingtreated the group as order Nematoda.[26]In 1877, thetaxonNematoidea, including the family Gordiidae (horsehair worms), was promoted to the rank of phylum byRay Lankester.The first clear distinction between the nemas and gordiids was realized byVejdovskywhen he named a group to contain the horsehair worms the order Nematomorpha. In 1919,Nathan Cobbproposed that nematodes should be recognized alone as a phylum.[29]He argued they should be called "nema" in English rather than "nematodes" and defined the taxon Nemates (later emended as Nemata, Latin plural ofnema), listing Nematoideasensu restrictoas a synonym.

However, in 1910, Grobben proposed the phylum Aschelminthes and the nematodes were included as class Nematoda along with class Rotifera, class Gastrotricha, class Kinorhyncha, class Priapulida, and class Nematomorpha (The phylum was later revived and modified byLibbie Henrietta Hymanin 1951 as Pseudoceolomata, but remained similar). In 1932, Potts elevated the class Nematoda to the level of phylum, leaving the name the same. Despite Potts' classification being equivalent to Cobbs', both names have been used (and are still used today) and Nematode became a popular term in zoological science.[30]

Since Cobb was the first to include nematodes in a particular phylum separated from Nematomorpha, some researchers consider the valid taxon name to be Nemates or Nemata, rather than Nematoda,[31]because of the zoological rule that gives priority to the first used term in case of synonyms.

Phylogeny

[edit]

Thephylogeneticrelationships of the nematodes and their close relatives among theprotostomianMetazoaare unresolved. Traditionally, they were held to be a lineage of their own, but in the 1990s, they were proposed to form the groupEcdysozoatogether withmoultinganimals, such asarthropods.The identity of the closest living relatives of the Nematoda has always been considered to be well resolved. Morphological characters and molecular phylogenies agree with placement of the roundworms as asister taxonto the parasiticNematomorpha;together, they make up theNematoida.Along with theScalidophora(formerly Cephalorhyncha), the Nematoida form the cladeCycloneuralia,but much disagreement occurs both between and among the available morphological and molecular data. The Cycloneuralia or the Introverta—depending on the validity of the former—are often ranked as asuperphylum.[32]

For an up-to-date view (as of 2022), seePhylogenomic Analysis of the Phylum Nematoda: Conflicts and Congruences With Morphology, 18S rRNA, and Mitogenomes.

Nematode systematics

[edit]

Due to the lack of knowledge regarding many nematodes, their systematics is contentious. An early and influential classification was proposed by Chitwood and Chitwood[33]—later revised by Chitwood[34]—who divided the phylum into two classes—AphasmidiaandPhasmidia.These were later renamedAdenophorea(gland bearers) and Secernentea (secretors), respectively.[35]The Secernentea share several characteristics, including the presence ofphasmids,a pair of sensory organs located in the lateral posterior region, and this was used as the basis for this division. This scheme was adhered to in many later classifications, though the Adenophorea were not in a uniform group.

Initial studies of incompleteDNA sequences[36]suggested the existence of fiveclades:[37]

The Secernentea seem to be a natural group of close relatives, while the "Adenophorea" appear to be aparaphyleticassemblage of roundworms that retain a good number ofancestral traits.The oldEnopliado not seem to be monophyletic, either, but do contain two distinct lineages. The old group "Chromadoria"seems to be another paraphyletic assemblage, with theMonhysteridarepresenting a very ancient minor group of nematodes. Among the Secernentea, theDiplogasteriamay need to be united with theRhabditia,while the Tylenchia might be paraphyletic with the Rhabditia.[38]

The understanding of roundworm systematics andphylogenyas of 2002 is summarised below:

Phylum Nematoda

Later work has suggested the presence of 12 clades.[39]The Secernentea—a group that includes virtually all major animal and plant 'nematode' parasites—apparently arose from within the Adenophorea.

In 2019, a study identified oneconserved signature indel(CSI) found exclusively in members of the phylum Nematoda through comparative genetic analyses.[40]The CSI consists of a single amino acid insertion within a conserved region of a Na(+)/H(+) exchange regulatory factor protein NRFL-1 and is a molecular marker that distinguishes the phylum from other species.[40]

A major effort by a collaborative wiki called 959 Nematode Genomes is underway to improve the systematics of this phylum.[41]

An analysis of the mitochondrial DNA suggests that the following groupings are valid[42]

In 2022 a new classification of the entire phylum Nematoda was presented by M. Hodda. It was based on current molecular, developmental and morphological evidence.[43]Under this classification, the following classes and subclasses are presented:

Fossil record

[edit]

Nematode eggs from thecladesAscaridina, Spirurina, and Trichocephalida have been discovered incoprolitesfrom theOligocene-aged Tremembé Formation, which represented apalaeolakein present-daySão Paulowith a diversefossilassemblage of birds, fish, and arthropods that lent itself to fostering high nematode diversity.[44]Nematodes have also been found in variouslagerstätten,such asBurmese amber,theMoltrasio Formation,and theRhynie chert,where the earliest known fossils are known from.

Anatomy

[edit]
Internal anatomy of a maleC. elegansnematode
Cross-section of femaleAscaris.The large circles filled with small green circles are the uterus and eggs. The long narrow feature is thedigestive tract.The smaller red and orange circles are theovariesandoviducts.The cluster of green and black blobs in the upper right and lower left are the nerve cords (ventralanddorsal). Surrounding the internal organs are the frilly green longitudinal muscles, the dark hypodermis, and the green outercuticle.

Nematodes are very small, slender worms: typically about 5 to 100 μm thick, and 0.1 to 2.5 mm long.[45]The smallest nematodes are microscopic, while free-living species can reach as much as 5 cm (2 in), and some parasitic species are larger still, reaching over 1 m (3 ft) in length.[46]: 271 The body is often ornamented with ridges, rings, bristles, or other distinctive structures.[47]

The head of a nematode is relatively distinct. Whereas the rest of the body is bilaterally symmetrical, the head is radially symmetrical, with sensory bristles and, in many cases, solid 'head-shields' radiating outwards around the mouth. The mouth has either three or six lips, which often bear a series of teeth on their inner edges. An adhesive 'caudal gland' is often found at the tip of the tail.[48]

Theepidermisis either asyncytiumor a single layer of cells, and is covered by a thickcollagenouscuticle.The cuticle is often of a complex structure and may have two or three distinct layers. Underneath the epidermis lies a layer of longitudinalmusclecells. The relatively rigid cuticle works with the muscles to create a hydroskeleton, as nematodes lack circumferential muscles. Projections run from the inner surface of muscle cells towards thenerve cords;this is a unique arrangement in the animal kingdom, in which nerve cells normally extend fibers into the muscles rather thanvice versa.[48]

Digestive system

[edit]

The oral cavity is lined with cuticles, which are often strengthened with structures, such as ridges, especially in carnivorous species, which may bear several teeth. The mouth often includes a sharpstylet,which the animal can thrust into its prey. In some species, the style is hollow and can be used to suck liquids from plants or animals.[48]

The oral cavity opens into a muscular, suckingpharynx,also lined with cuticle. Digestive glands are found in this region of the gut, producingenzymesthat start to break down the food. In stylet-bearing species, these may even be injected into the prey.[48]

Nostomachis present, with the pharynx connecting directly to a musclelessintestinethat forms the main length of the gut. This produces further enzymes and also absorbs nutrients through its single-cell-thick lining. The last portion of the intestine is lined by a cuticle, forming arectum,which expels waste through theanusjust below and in front of the tip of the tail. The movement of food through the digestive system is the result of the body movements of the worm. The intestine has valves orsphinctersat either end to help control food movement through the body.[48]

Excretory system

[edit]

Nitrogenous wasteis excreted in the form ofammoniathrough the body wall, and is not associated with any specific organs. However, the structures for excreting salt to maintainosmoregulationare typically more complex.[48]

In many marine nematodes, one or two unicellular 'renette glands' excrete salt through a pore on the underside of the animal, close to the pharynx. In most other nematodes, these specialized cells have been replaced by an organ consisting of two parallel ducts connected by a single transverse duct. This transverse duct opens into a common canal that runs to the excretory pore.[48]

Nervous system

[edit]
See also:Muscle arms

At the anterior end of the animal a dense, circularnerve ringwhich serves as thebrainsurrounds the pharynx.[48]From this ring six labial papillary nerve cords extend anteriorly, while six nerve cords; a large ventral, a smaller dorsal and two pairs of sublateral cords extend posteriorly.[49]Each nerve lies within a cord of connective tissue lying beneath the cuticle and between the muscle cells. Theventral nerveis the largest, and has a double structure forward of theexcretorypore.The dorsal nerve is responsible for motor control, while the lateral nerves are sensory, and the ventral combines both functions.[48]

The nervous system is also the only place in the nematode body that containscilia,which are all nonmotile and with a sensory function.[50][51]

The bodies of nematodes are covered in numerous sensorybristlesandpapillaethat together provide a sense of touch. Behind the sensory bristles on the head lie two small pits, or 'amphids'. These are well supplied with nerve cells and are probablychemoreceptionorgans. A few aquatic nematodes possess what appear to bepigmentedeye-spots, but whether or not these are actually sensory in nature is unclear.[48]

Reproduction

[edit]
Extremity of a male nematode showing thespicule,used for copulation, bar = 100 μm[52]

Most nematode species aredioecious,with separate male and female individuals, though some, such asCaenorhabditis elegans,areandrodioecious,consisting ofhermaphroditesand rare males. Both sexes possess one or two tubulargonads.In males, the sperm are produced at the end of the gonad and migrate along its length as they mature. The testis opens into a relatively wideseminal vesicleand then during intercourse into a glandular and muscular ejaculatory duct associated with thevas deferensandcloaca.In females, the ovaries each open into anoviduct(in hermaphrodites, the eggs enter aspermathecafirst) and then a glandularuterus.The uteri both open into a common vulva/vagina, usually located in the middle of the morphologically ventral surface.[48]

Reproduction is usually sexual, though hermaphrodites are capable of self-fertilization. Males are usually smaller than females or hermaphrodites (often much smaller) and often have a characteristically bent or fan-shaped tail. Duringcopulation,one or morechitinizedspiculesmove out of the cloaca and are inserted into the genital pore of the female.Amoeboidspermcrawl along the spicule into the female worm. Nematode sperm is thought to be the onlyeukaryotic cellwithout the globular proteinG-actin.[citation needed]

Eggs may beembryonatedor unembryonated when passed by the female, meaning their fertilized eggs may not yet be developed. A few species are known to beovoviviparous.The eggs are protected by an outer shell, secreted by the uterus. In free-living roundworms, the eggs hatch intolarvae,which appear essentially identical to the adults, except for an underdeveloped reproductive system; in parasitic roundworms, the lifecycle is often much more complicated.[48]The structure of the eggshell is complicated and includes several layers; a detailed anatomical and terminological framework has been proposed for these layers in 2023.[53]

Nematodes as a whole possess a wide range of modes of reproduction.[54]Some nematodes, such asHeterorhabditisspp., undergo a process calledendotokia matricida:intrauterine birth causing maternal death.[55]Some nematodes arehermaphroditic,and keep their self-fertilized eggs inside theuterusuntil they hatch. The juvenile nematodes then ingest the parent nematode. This process is significantly promoted in environments with a low food supply.[55]

The nematode model speciesC. elegans,C. briggsae,andPristionchus pacificus,among other species, exhibitandrodioecy,[56]which is otherwise very rare among animals. The singlegenusMeloidogyne(root-knot nematodes) exhibits a range of reproductive modes, includingsexual reproduction,facultative sexuality (in which most, but not all, generations reproduce asexually), and bothmeioticandmitoticparthenogenesis.

The genusMesorhabditisexhibits an unusual form of parthenogenesis, in which sperm-producing males copulate with females, but the sperm do not fuse with the ovum. Contact with the sperm is essential for the ovum to begin dividing, but because no fusion of the cells occurs, the male contributes no genetic material to the offspring, which are essentiallyclonesof the female.[48]

Aging

[edit]

The nematodeCaenorhabditis elegansis often used as a model organism for studyingagingat the molecular level. For example, inC. elegansaging negatively impactsDNA repair,and mutants ofC. elegansthat are long-lived were shown to have increased DNA repair capability.[57]These findings suggest a genetically determined correlation between DNA repair capacity and lifespan.[57]In femaleC. elegans,germlineprocesses that control DNA repair and formation ofchromosomal crossoversduringmeiosiswere shown to progressively deteriorate with age.[58]

Free-living species

[edit]

Different free-living species feed on materials as varied asbacteria,algae,fungi,small animals, fecal matter, dead organisms, and living tissues. Free-living marine nematodes are important and abundant members of themeiobenthos.They play an important role in the decomposition process, aid in recycling of nutrients in marine environments, and are sensitive to changes in the environment caused by pollution. One roundworm of note,C. elegans,lives in the soil and has found much use as amodel organism.C. eleganshas had its entire genome sequenced, the developmental fate of every cell determined, and every neuron mapped.

Parasitic species

[edit]
Eggs (mostly nematodes) from stools of wildprimates

Nematodes that commonly parasitise humans includeascarids(Ascaris),filarias,hookworms,pinworms(Enterobius), andwhipworms(Trichuris trichiura). The speciesTrichinella spiralis,commonly known as the 'trichina worm', occurs in rats, pigs, bears, and humans, and is responsible for the diseasetrichinosis.Baylisascarisusually infests wild animals, but can be deadly to humans, as well.Dirofilaria immitisis known for causing heartworm disease by inhabiting the hearts, arteries, and lungs of dogs and some cats.Haemonchus contortusis one of the most abundant infectious agents in sheep around the world, causing great economic damage to sheep. In contrast,entomopathogenic nematodesparasitize insects and are mostly considered beneficial by humans, but some attack beneficial insects.

One form of nematode is entirely dependent uponfig wasps,which are the sole source offigfertilization. They prey upon the wasps, riding them from the ripe fig of the wasp's birth to the fig flower of its death, where they kill the wasp, and their offspring await the birth of the next generation of wasps as the fig ripens.

Colorizedelectron micrographofsoybean cyst nematode(Heteroderasp.) and egg

A parasitic tetradonematid nematode discovered in 2005,Myrmeconema neotropicum,induces fruit mimicry in the tropical antCephalotes atratus.Infected ants develop bright redgasters(abdomens), tend to be more sluggish, and walk with their gasters in a conspicuous elevated position. These changes likely causefrugivorousbirds to confuse the infected ants for berries, and eat them. Parasite eggs passed in the bird'sfecesare subsequently collected by foragingC. atratusand are fed to theirlarvae,thus completing the lifecycle ofM. neotropicum.[59]

Similarly, multiple varieties of nematodes have been found in the abdominal cavities of the primitively social sweat bee,Lasioglossum zephyrus.Inside the female body, the nematode hinders ovarian development and renders the bee less active, thus less effective in pollen collection.[60]

Agriculture and horticulture

[edit]

Depending on its species, a nematode may be beneficial or detrimental to plant health. From agricultural andhorticultureperspectives, the two categories of nematodes are the predatory ones, which kill garden pests; and the pest nematodes, which attack plants, or act asvectorsspreadingplant virusesbetween crop plants.[61] Predatory nematodes includePhasmarhabditis hermaphroditawhich is a lethal parasite of gastropods such asslugsandsnails.[62]Some members of the genusSteinernemasuch asSteinernema carpocapsaeandSteinernema riobraveare generalist parasites ofwebworms,cutworms,armyworms,girdlers,someweevils,wood-borersandcorn earworm moths.[63]These organisms are grown commercially asbiological pest controlagents which can be used as an alternative topesticides;their use is considered very safe.[64]Plant-parasitic nematodes include several groups causing severe crop losses, taking 10% of crops worldwide every year.[65]The most common genera areAphelenchoides(foliar nematodes),Ditylenchus,Globodera(potato cyst nematodes),Heterodera(soybean cyst nematodes),Longidorus,Meloidogyne(root-knot nematodes),Nacobbus,Pratylenchus(lesion nematodes),Trichodorus,andXiphinema(dagger nematodes). Several phytoparasitic nematode species cause histological damages to roots, including the formation of visible galls (e.g. by root-knot nematodes), which are useful characters for their diagnostic in the field. Some nematode species transmit plant viruses through their feeding activity on roots. One of them isXiphinema index,vector ofgrapevine fanleaf virus,an important disease of grapes, another one isXiphinema diversicaudatum,vector ofarabis mosaic virus.Other nematodes attack bark and forest trees. The most important representative of this group isBursaphelenchus xylophilus,the pine wood nematode, present in Asia and America and recently discovered in Europe. This nematode is transmitted from tree to tree by sawyer beetles (Monochamus).[66]

Greenhouse growers usebeneficial nematodesto controlfungus gnats,the nematodes enter the larva of the gnats by way of their anus, mouth, andspiracles(breathing pores) and then release abacteriawhich kills the gnat larvae; commonly used nematode species to control pests on greenhouse crops includeSteinernemafeltiaefor fungus gnats andwestern flower thrips,Steinernema carpocapsaeused to control shore flies,Steinernema krausseifor control ofblack vine weevils,andHeterorhabditis bacteriophorato control beetle larvae.[67]

Rotations of plants with nematode-resistant species or varieties is one means of managing parasitic nematode infestations. For example, plantingTagetes marigoldsas a cover crop just prior to planting a nematode-susceptible plant, has been shown to suppress nematodes.[68]Another is treatment with natural antagonists such as the fungusGliocladium roseum.Chitosan,a naturalbiocontrol,elicits plant defense responses to destroy parasiticcystnematodes on roots ofsoybean,corn,sugar beet,potato,andtomatocrops without harming beneficial nematodes in the soil.[69]Soil steamingis an efficient method to kill nematodes before planting a crop, but indiscriminately eliminates both harmful and beneficial soil fauna.

The golden nematodeGlobodera rostochiensisis a particularly harmful variety of nematode pest that has resulted in quarantines and crop failures worldwide.CSIROhas found a 13- to 14-fold reduction of nematode population densities in plots havingChinese mustardBrassica junceagreen manure or seed meal in the soil.[70]

Epidemiology

[edit]
Disability-adjusted life yearfor intestinal nematode infections per 100,000 in 2002.
< 25
25–50
50–75
75–100
100–120
120–140
140–160
160–180
180–200
200–220
220–240
> 240
no data
Anthelminticeffect ofpapainonHeligmosomoides bakeri

A number of intestinal nematodes cause diseases affecting human beings, includingascariasis,trichuriasis,andhookworm disease.Filarial nematodes causefilariases.Furthermore, studies have shown that parasitic nematodes infect American eels causing damage to the eel's swim bladder,[71]dairy animals like cattle and buffalo,[72]and all species of sheep.[73]

Gastrointestinal nematode infections in humans are common, with approximately 50% of the global population being affected. Developing countries are most heavily impacted, in part due to lack of access to medical care.[74]

Soil ecosystems

[edit]
Further information:Soil ecology

About 90% of nematodes reside in the top 15 cm (6 ") of soil. Nematodes do not decompose organic matter, but, instead, are parasitic and free-living organisms that feed on living material. Nematodes can effectively regulate bacterial population and community composition—they may eat up to 5,000 bacteria per minute. Also, nematodes can play an important role in thenitrogen cycleby way of nitrogen mineralization.[45]

One group ofcarnivorous fungi,thenematophagous fungi,are predators of soil nematodes.[75]They set enticements for the nematodes in the form of lassos or adhesive structures.[76][77][78]

Survivability

[edit]
See also:List of longest-living organisms § Revived into activity after stasis

Nematode worms (C. elegans), part of an ongoing research project conducted on the 2003Space ShuttleColumbiamissionSTS-107,survived there-entry breakup.It is believed to be the first known life form to survive a virtually unprotected atmospheric descent to Earth's surface.[79][80]In a research project published in 2012, it was found that the Antarctic Nematodes (P. davidi) was able to withstand intracellular freezing depending on how well it was fed.[81]In 2023 it was reported that an individual ofPanagrolaimus kolymaensishad been revived after 46,000 years in Siberian permafrost.[82]

See also

[edit]

References

[edit]
  1. ^Poinar, George; Kerp, Hans; Hass, Hagen (January 2008)."Palaeonema phyticumgen. n., sp. n. (Nematoda: Palaeonematidae fam. n.), a Devonian nematode associated with early land plants ".Nematology.10(1): 9–14.doi:10.1163/156854108783360159.
  2. ^Maas, Andreas; Waloszek, Dieter; Haug, Joachim; Müller, Klaus (January 2007)."A possible larval roundworm from the Cambrian 'Orsten' and its bearing on the phylogeny of Cycloneuralia".Memoirs of the Association of Australasian Palaeontologists.34:499–519.
  3. ^ab"Nematodes".Retrieved11 October2023.
  4. ^Hay, Frank."Nematodes - the good, the bad and the ugly".APS News & Views.apsnet.org.American Phytopathological Society.Retrieved28 November2020.
  5. ^Baker, Emily A.; Woollard, Alison (2019)."How weird is the worm? Evolution of the developmental gene toolkit inCaenorhabditis elegans".Journal of Developmental Biology.7(4): 19.doi:10.3390/jdb7040019.PMC6956190.PMID31569401.
  6. ^Hodda, M (2011). Zhang, Z.-Q. (ed.). "Phylum Nematoda(Cobb, 1932)".Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness.Zootaxa.3148:63–95.doi:10.11646/zootaxa.3148.1.11.
  7. ^Zhang, Z. (2013). Zhang, Z.-Q. (ed.)."Animal biodiversity: An update of classification and diversity in 2013".Animal biodiversity: An update of classification and diversity (Addenda 2013).Zootaxa.3703(1): 5–11.doi:10.11646/zootaxa.3703.1.3.
  8. ^ Lambshead, P. John D. (January 1993)."Recent developments in marine benthic biodiversity research".Oceanis.19(6): 5–24.Retrieved5 November2018– via ResearchGate.
  9. ^ Anderson, Roy C. (2000).Nematode Parasites of Vertebrates: Their Development and Transmission.CABI. pp. 1–2.doi:10.1079/9780851994215.0000.ISBN978-0-85199-421-5.OCLC559243334.Estimates of 500,000 to a million species have no basis in fact.
  10. ^ Lambshead PJ, Boucher G (2003)."Marine nematode deep-sea biodiversity—hyperdiverse or hype?".Journal of Biogeography.30(4): 475–485.Bibcode:2003JBiog..30..475L.doi:10.1046/j.1365-2699.2003.00843.x.S2CID86504164.
  11. ^ Qing X, Bert W (2019)."Family Tylenchidae (Nematoda): an overview and perspectives".Organisms Diversity & Evolution.19(3): 391–408.doi:10.1007/s13127-019-00404-4.S2CID190873905.
  12. ^ Floyd R, Abebe E, Papert A, Blaxter M (2002)."Molecular barcodes for soil nematode identification".Molecular Ecology.11(4): 839–850.Bibcode:2002MolEc..11..839F.doi:10.1046/j.1365-294X.2002.01485.x.PMID11972769.S2CID12955921.
  13. ^ Derycke S, Sheibani Tezerji R, Rigaux A, Moens T (2012)."Investigating the ecology and evolution of cryptic marine nematode species through quantitative real-time PCR of the ribosomal ITS region".Molecular Ecology Resources.12(4): 607–619.doi:10.1111/j.1755-0998.2012.03128.x.hdl:1854/LU-3127487.PMID22385909.S2CID4818657.
  14. ^ Blaxter, Mark (2016)."Imagining Sisyphus happy: DNA barcoding and the unnamed majority".Philosophical Transactions of the Royal Society of London B.371(1702): 20150329.doi:10.1098/rstb.2015.0329.PMC4971181.PMID27481781.
  15. ^ab Borgonie G, García-Moyano A, Litthauer D, Bert W, Bester A, van Heerden E, Möller C, Erasmus M, Onstott TC (June 2011)."Nematoda from the terrestrial deep subsurface of South Africa".Nature.474(7349): 79–82.Bibcode:2011Natur.474...79B.doi:10.1038/nature09974.hdl:1854/LU-1269676.PMID21637257.S2CID4399763.
  16. ^ Lemonick, M.D. (8 June 2011)."Could 'worms from Hell' mean there's life in space?".Time.ISSN0040-781X.Archived fromthe originalon 10 June 2011.Retrieved8 June2011.
  17. ^ Bhanoo, S.N. (1 June 2011)."Nematode found in mine is first subsurface multicellular organism".The New York Times.ISSN0362-4331.Retrieved13 June2011.
  18. ^ "Gold mine".Nature.474(7349): 6. June 2011.doi:10.1038/474006b.PMID21637213.
  19. ^ Drake N (1 June 2011)."Subterranean worms from hell".Nature news.Nature News.doi:10.1038/news.2011.342.Retrieved13 June2011.
  20. ^ Danovaro R, Gambi C, Dell'Anno A, Corinaldesi C, Fraschetti S, Vanreusel A, et al. (January 2008)."Exponential decline of deep-sea ecosystem functioning linked to benthic biodiversity loss".Curr. Biol.18(1): 1–8.Bibcode:2008CBio...18....1D.doi:10.1016/j.cub.2007.11.056.PMID18164201.S2CID15272791.
  21. ^ab van den Hoogen, Johan; Geisen, Stefan; Routh, Devin; Ferris, Howard; Traunspurger, Walter; Wardle, David A.; et al. (24 July 2019)."Soil nematode abundance and functional group composition at a global scale".Nature.572(7768): 194–8.Bibcode:2019Natur.572..194V.doi:10.1038/s41586-019-1418-6.hdl:20.500.11755/c8c7bc6a-585c-4a13-9e36-4851939c1b10.ISSN0028-0836.PMID31341281.S2CID198492891.Archived fromthe originalon 2 March 2020.Retrieved10 December2019.
  22. ^ Platt HM (1994). "foreword". In Lorenzen S, Lorenzen SA (eds.).The phylogenetic systematics of freeliving nematodes.Ray Society (Series). Vol. 162. London, UK: Ray Society.ISBN978-0-903874-22-9.OCLC1440106662.
  23. ^ Cary, S. Craig; Green, T.G. Allan; Storey, Bryan C.; Sparrow, Ashley D.; Hogg, Ian D.; Katurji, Marwan; et al. (15 February 2019)."Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem".Communications Biology.2(1): 62.doi:10.1038/s42003-018-0274-5.PMC6377621.PMID30793041.
  24. ^ Adams, Byron J.; Wall, Diana H.; Storey, Bryan C.; Green, T.G. Allan; Barrett, John E.; Cary, S. Craig; et al. (15 February 2019)."Nematodes in a polar desert reveal the relative role of biotic interactions in the coexistence of soil animals".Communications Biology.2(1): 63.doi:10.1038/s42003-018-0260-y.PMC6377602.PMID30793042.
  25. ^ab Anderson, Roy C. (8 February 2000).Nematode Parasites of Vertebrates: Their development and transmission.CABI. p. 1.ISBN978-0-85199-786-5.
  26. ^abcChitwood BG (1957). "The English word" Nema "revised".Systematic Biology.4(45): 1619.doi:10.2307/sysbio/6.4.184.
  27. ^Siddiqi MR (2000).Tylenchida: Parasites of plants and insects.Wallingford, Oxon, UK: CABI Pub.ISBN978-0-85199-202-0.
  28. ^Schmidt-Rhaesa A (2014). "Gastrotricha, Cycloneuralia, and Gnathifera: General history and phylogeny". In Schmidt-Rhaesa A (ed.).Handbook of Zoology (founded by W. Kükenthal).Vol. 1, Nematomorpha, Priapulida, Kinorhyncha, Loricifera. Berlin, Boston: de Gruyter.
  29. ^Cobb NA (1919)."The orders and classes of nemas".Contrib. Sci. Nematol.8:213–6.
  30. ^Wilson, E.O."Phylum Nemata".nematode.unl.edu.Plant and insect parasitic nematodes. Archived fromthe originalon 30 April 2018.Retrieved29 April2018.
  31. ^ Nematoda.Itis.gov(Report). ITIS Report.Retrieved12 June2012.
  32. ^"Bilateria".Tree of Life (tolweb.org).Tree of Life Web Project.2002.Retrieved2 November2008.
  33. ^Chitwood BG, Chitwood MB (1933). "The characters of a protonematode".J Parasitol.20:130.
  34. ^Chitwood BG (1937). "A revised classification of theNematoda".Papers on Helminthology published in commemoration of the 30 year Jubileum of... K.J. Skrjabin...Moscow: All-Union Lenin Academy of Agricultural Sciences. pp. 67–79.
  35. ^Chitwood BG (1958)."The designation of official names for higher taxa of invertebrates".Bull Zool Nomencl.15:860–895.doi:10.5962/bhl.part.19410.
  36. ^Coghlan, A. (7 September 2005)."Nematode genome evolution"(PDF).WormBook:1–15.doi:10.1895/wormbook.1.15.1.PMC4781476.PMID18050393.Archived fromthe original(PDF)on 5 March 2016.Retrieved13 January2016.
  37. ^Blaxter ML, De Ley P, Garey JR, Liu LX, Scheldeman P, Vierstraete A, Vanfleteren JR, Mackey LY, Dorris M, Frisse LM, Vida JT, Thomas WK (March 1998). "A molecular evolutionary framework for the phylum Nematoda".Nature.392(6671): 71–75.Bibcode:1998Natur.392...71B.doi:10.1038/32160.PMID9510248.S2CID4301939.
  38. ^"Nematoda".Tree of Life Web Project.2002.Retrieved2 November2008.
  39. ^ Holterman M, van der Wurff A, van den Elsen S, van Megen H, Bongers T, Holovachov O, Bakker J, Helder J (2006)."Phylum-wide analysis of SSU rDNA reveals deep phylogenetic relationships among nematodes and accelerated evolution toward crown Clades".Mol Biol Evol.23(9): 1792–1800.doi:10.1093/molbev/msl044.PMID16790472.
  40. ^abKhadka, Bijendra; Chatterjee, Tonuka; Gupta, Bhagwati P.; Gupta, Radhey S. (24 September 2019)."Genomic Analyses Identify Novel Molecular Signatures Specific for theCaenorhabditisand other Nematode Taxa Providing Novel Means for Genetic and Biochemical Studies ".Genes.10(10): 739.doi:10.3390/genes10100739.PMC6826867.PMID31554175.
  41. ^ "959 nematode genomes".NematodeGenomes.Nematodes.org.11 November 2011. Archived fromthe originalon 5 August 2015.Retrieved12 June2012.
  42. ^Liu GH, Shao R, Li JY, Zhou DH, Li H, Zhu XQ (2013)."The complete mitochondrial genomes of three parasitic nematodes of birds: a unique gene order and insights into nematode phylogeny".BMC Genomics.14(1): 414.doi:10.1186/1471-2164-14-414.PMC3693896.PMID23800363.
  43. ^Hodda, M. (2022)."Phylum Nematoda: a classification, catalogue and index of valid genera, with a census of valid species".Zootaxa.5114(1): 1–289.doi:10.11646/zootaxa.5114.1.1.PMID35391386.
  44. ^Macêdo do Carmo, Gustavo; Garcia, Renato Araujo; Vieira, Fabiano Matos; de Souza Lima, Sueli; Ismael de Araújo-Júnior, Hermínio; Pinheiro, Ralph Maturano (May 2023)."Paleoparasitological study of avian trace fossils from the Tremembé Formation (Oligocene of the Taubaté Basin), São Paulo, Brazil".Journal of South American Earth Sciences.125:104319.Bibcode:2023JSAES.12504319M.doi:10.1016/j.jsames.2023.104319.Retrieved12 April2024– via Elsevier Science Direct.
  45. ^abBrady, Nyle C.; Weil, Ray R. (2009).Elements of the Nature and Properties of Soils(3rd ed.). Prentice Hall.ISBN978-0-13-501433-2.OCLC1015309711.
  46. ^Ruppert EE, Fox RS, Barnes RD (2004).Invertebrate Zoology: A Functional Evolutionary Approach(7th ed.). Belmont, California: Brooks/Cole.ISBN978-0-03-025982-1.
  47. ^ Weischer B, Brown DJ (2000).An Introduction to Nematodes: General Nematology.Sofia, Bulgaria: Pensoft. pp. 75–76.ISBN978-954-642-087-9.
  48. ^abcdefghijklmBarnes RG (1980).Invertebrate zoology.Philadelphia: Sanders College.ISBN978-0-03-056747-6.
  49. ^Huang, Yong; Guo, Yuqing (27 November 2021).Free-living Marine Nematodes from the East China Sea.Springer Nature.ISBN978-981-16-3836-7– via Google Books.
  50. ^"The sensory cilia ofCaenorhabditis elegans".www.wormbook.org.
  51. ^Kavlie, RG; Kernan, MJ; Eberl, DF (May 2010)."Hearing in Drosophila requires TilB, a conserved protein associated with ciliary motility".Genetics.185(1): 177–88.doi:10.1534/genetics.110.114009.PMC2870953.PMID20215474.
  52. ^Lalošević, V.; Lalošević, D.; Capo, I.; Simin, V.; Galfi, A.; Traversa, D. (2013)."High infection rate of zoonoticEucoleus aerophilusinfection in foxes from Serbia ".Parasite.20:3.doi:10.1051/parasite/2012003.PMC3718516.PMID23340229.
  53. ^Bond, Alan Thomas; Huffman, David George (2023)."Nematode eggshells: A new anatomical and terminological framework, with a critical review of relevant literature and suggested guidelines for the interpretation and reporting of eggshell imagery".Parasite.30:6.doi:10.1051/parasite/2023007.PMC10016204.PMID36920277.Open access icon
  54. ^Bell G (1982).The masterpiece of nature: the evolution and genetics of sexuality.Berkeley: University of California Press.ISBN978-0-520-04583-5.
  55. ^abJohnigk SA, Ehlers RU (1999). "Endotokia matricidain hermaphrodites ofHeterorhabditisspp. and the effect of the food supply ".Nematology.1(7–8): 717–726.doi:10.1163/156854199508748.ISSN1388-5545.S2CID85279418.
  56. ^ Haag ES, Helder J, Mooijman PJ, Yin D, Hu S (2018)."The evolution of uniparental reproduction in Rhabditina nematodes: Phylogenetic patterns, developmental causes, and surprising consequences".In Leonard, J.L. (ed.).Transitions Between Sexual Systems.Springer. pp. 99–122.doi:10.1007/978-3-319-94139-4_4.ISBN978-3-319-94137-0.
  57. ^abHyun M, Lee J, Lee K, May A, Bohr VA, Ahn B (March 2008)."Longevity and resistance to stress correlate with DNA repair capacity inCaenorhabditis elegans".Nucleic Acids Res.36(4): 1380–9.doi:10.1093/nar/gkm1161.PMC2275101.PMID18203746.
  58. ^Raices M, Bowman R, Smolikove S, Yanowitz JL (2021)."Aging Negatively Impacts DNA Repair and Bivalent Formation in theC. elegansGerm Line ".Front Cell Dev Biol.9:695333.doi:10.3389/fcell.2021.695333.PMC8371636.PMID34422819.
  59. ^Yanoviak SP, Kaspari M, Dudley R, Poinar G (April 2008). "Parasite-induced fruit mimicry in a tropical canopy ant".Am. Nat.171(4): 536–44.doi:10.1086/528968.PMID18279076.S2CID23857167.
  60. ^Batra, Suzanne W. T. (1 October 1965). "Organisms associated withLasioglossum zephyrum(Hymenoptera: Halictidae) ".Journal of the Kansas Entomological Society.38(4): 367–389.JSTOR25083474.
  61. ^Purcell M, Johnson MW, Lebeck LM, Hara AH (1992). "Biological Control of Helicoverpa zea (Lepidoptera: Noctuidae) with Steinernema carpocapsae (Rhabditida: Steinernematidae) in Corn Used as a Trap Crop".Environmental Entomology.21(6): 1441–7.doi:10.1093/ee/21.6.1441.
  62. ^Wilson, M. J.; Glen, D. M.; George, S. K. (January 1993). "The rhabditid nematode Phasmarhabditis hermaphrodita as a potential biological control agent for slugs".Biocontrol Science and Technology.3(4): 503–511.Bibcode:1993BioST...3..503W.doi:10.1080/09583159309355306.
  63. ^Rajamani, Meenatchi; Negi, Aditi (2021). "Biopesticides for Pest Management".Sustainable Bioeconomy.pp. 239–266.doi:10.1007/978-981-15-7321-7_11.ISBN978-981-15-7320-0.S2CID228845133.
  64. ^Ehlers, R.-U.; Hokkanen, H. M. T. (September 1996). "Insect Biocontrol with Non-endemic Entomopathogenic Nematodes (Steinernema and Heterorhabditis spp.): Conclusions and Recommendations of a Combined OECD and COST Workshop on Scientific and Regulatory Policy Issues".Biocontrol Science and Technology.6(3): 295–302.Bibcode:1996BioST...6..295E.doi:10.1080/09583159631280.
  65. ^Smiley RW, Dababat AA, Iqbal S, Jones MG, Maafi ZT, Peng D,Subbotin SA,Waeyenberge L (2017)."Cereal Cyst Nematodes: A Complex and Destructive Group ofHeteroderaSpecies ".Plant Disease.101(10).American Phytopathological Society:1692–1720.doi:10.1094/pdis-03-17-0355-fe.ISSN0191-2917.PMID30676930.
  66. ^Gibbs, J.N.; Webber, J.F. (2004),"PATHOLOGY | Insect Associated Tree Diseases",Encyclopedia of Forest Sciences,Elsevier, pp. 802–8,doi:10.1016/b0-12-145160-7/00070-3,ISBN978-0-12-145160-8,retrieved21 March2023
  67. ^Kloosterman, Stephen (April 2022). "Small Soldiers".Green House Product News.Vol. 32, no. 4. pp. 26–29.
  68. ^R. Krueger; K. E. Dover; R. McSorley; K-H. Wang."ENY-056/NG045: Marigolds (Tagetes spp.) for Nematode Management".Institute of Food and Agricultural Sciences.Retrieved20 November2023.
  69. ^US application 2008072494,Stoner RJ, Linden JC, "Micronutrient elicitor for treating nematodes in field crops", published 2008-03-27
  70. ^ Loothfar R, Tony S (22 March 2005)."Suppression of root knot nematode (Meloidogyne javanica) after incorporation of Indian mustard cv. Nemfix as green manure and seed meal in vineyards ".Australasian Plant Pathology.34(1): 77–83.Bibcode:2005AuPP...34...77R.doi:10.1071/AP04081.S2CID24299033.Retrieved14 June2010.
  71. ^Warshafsky, Z. T., Tuckey, T. D., Vogelbein, W. K., Latour, R. J., & Wargo, A. R. (2019). Temporal, spatial, and biological variation of nematode epidemiology in American eels. Canadian Journal of Fisheries & Aquatic Sciences, 76(10), 1808–1818.https://doi.org/10.1139/cjfas-2018-0136
  72. ^Jithendran, & Bhat, T.. (1999). Epidemiology of Parasitoses in Dairy Animals in the North West Humid Himalayan Region of India with Particular Reference to Gastrointestinal Nematodes. Tropical Animal Health and Production, 31(4), 205–214.https://doi.org/10.1023/A:1005263009921
  73. ^Morgan ER, van Dijk J (September 2012). "Climate and the epidemiology of gastrointestinal nematode infections of sheep in Europe".Vet Parasitol.189(1): 8–14.doi:10.1016/j.vetpar.2012.03.028.PMID22494941.
  74. ^Stepek, Gillian; Buttle, David J; Duce, Ian R; Behnke, Jerzy M (October 2006)."Human gastrointestinal nematode infections: are new control methods required?".International Journal of Experimental Pathology.87(5): 325–341.doi:10.1111/j.1365-2613.2006.00495.x.PMC2517378.PMID16965561.
  75. ^Nosowitz, Fan (8 February 2021)."How California Crops Fought Off a Pest Without Using Pesticide".Modern Farmer.Retrieved15 February2021.
  76. ^ Pramer C (1964). "Nematode-trapping fungi".Science.144(3617): 382–8.Bibcode:1964Sci...144..382P.doi:10.1126/science.144.3617.382.PMID14169325.
  77. ^Hauser JT (December 1985)."Nematode-trapping fungi"(PDF).Carnivorous Plant Newsletter.14(1): 8–11.doi:10.55360/cpn141.jh945.
  78. ^ Ahrén D, Ursing BM, Tunlid A (1998). "Phylogeny of nematode-trapping fungi based on 18S rDNA sequences".FEMS Microbiology Letters.158(2): 179–184.doi:10.1111/j.1574-6968.1998.tb12817.x.PMID9465391.
  79. ^"Columbia Survivors".Astrobiology Magazine.1 January 2006. Archived from the original on 4 March 2016.Retrieved12 January2016.{{cite magazine}}:CS1 maint: unfit URL (link)
  80. ^Szewczyk, Nathaniel J.; Mancinelli, Rocco L.; McLamb, William; Reed, David; Blumberg, Baruch S.; Conley, Catharine A. (December 2005). "Caenorhabditis elegansSurvives Atmospheric Breakup of STS–107, Space Shuttle Columbia ".Astrobiology.5(6): 690–705.Bibcode:2005AsBio...5..690S.doi:10.1089/ast.2005.5.690.PMID16379525.
  81. ^ Raymond, Mélianie R.; Wharton, David A. (February 2013)."The ability of the Antarctic nematodePanagrolaimus davidito survive intracellular freezing is dependent upon nutritional status ".Journal of Comparative Physiology B.183(2): 181–8.doi:10.1007/s00360-012-0697-0.ISSN0174-1578.PMID22836298.S2CID17294698.
  82. ^ Shatilovich, Anastasia; Gade, Vamshidhar r. (27 July 2023)."A novel nematode species from the Siberian permafrost shares adaptive mechanisms for cryptobiotic survival withC. elegansdauer larva ".PLOS Genetics.19(7): e1010798.doi:10.1371/journal.pgen.1010798.PMC10374039.PMID37498820.

Further reading

[edit]
[edit]
Wikimedia Commons has media related toNematoda.
Wikisourcehas the text of the1911Encyclopædia Britannicaarticle "Nematoda".
Retrieved from "https://en.wikipedia.org/w/index.php?title=Nematode&oldid=1253356479"