NEMATODE STRUCTURE -Used to identify nematodes -Identifying ...

NEMATODE STRUCTURE-Used to identify nematodes-Identifying nematodes = diagnose disease or risk-Diagnosis necessary for correct management

NEMATODE STRUCTURE-Invertebrate animals-Unsegmented roundworms “tube within a tube”Plectus parietinusHirschmann

NEMATODE STRUCTURE- Bilaterally symmetrical- Well developed digestive, reproductive,nervous systems- No circulatory or respiratory systemAccomplished by movement of fluids in body- Longitudinal muscles, but no circular muscles- Lengths range from 0.003 in. (marine sediments)to 27 feet (parasite in placenta of whales)- Plant-pathogenic nematodes are 0.01-0.22 in.

Kathy Merrifield

Nematode MorphologyBody wall = Cuticle-Multilayered, nonliving, noncellular-Flexible exoskeleton, enters body openings-Semipermiable (O 2 , H 2 O, solutes)Hirshmann

Nematode MorphologyCuticular StructuresFreckman,Baldwin-Many structures can be foundon the cuticle-Few are important to identifyplant-pathogenic nematodes-Alae = expansions, projectionsCervical = neck regionLongitudinal = side of bodyCaudal = bursa, supplements

Cuticle = outside cover of nematodeTransverse markings = “striae”Areas between striae = “annules”Raised area along side of nematode = “lateral field”with one lateral lineJ.D. Eisenback

No AnnulationCoarse AnnulationKathy Merrifield

Lateral field withthree lateral lines,separated byincisuresM.A. McClure

As nematodes grow they moltto shed their cuticle

StyletMedianBulbLipsProcorpusBursaSpicules in cloacaEggIntestineTestisLateralLinesLobe of esophagus glandoverlapping intestineOvaryIntestineVulvaPostuterine Sac(Present in species with 1 ovary)AnusTailBasic Nematode Body Design

Nematode MorphologyCephalic Region = Head, Lips etc.P = PapillaeI = innerO = outerC = cephalicA = AmphidsMouth“Tripartite”

Xiphinema americanumMouthPore-likeAmphid(taste)Lips (6 total)Papillae (touch, taste)C.H. Hopper

ProbolaeLips may be replaced by probolae,hooks or teethAcrobeles sp.U. Zunke

Papillae may be elongated into setaePapillae and setae are called sensillaDarwin Nematode Project

Soil Dwelling NematodesNon-Stylet BearersBacteriaAlgaeYeastsPredatorsStylet BearersHigher PlantsFungiPredators

Nematode MorphologyCephalic Region = Stoma (Buccal Cavity)Stomatostylet = derived from wall of stoma

Rhabditis ?Bacterial FeederNarrow StomaU. Zunke

Panagrellus sp.Bacterial FeederWide StomaJ.D. Eisenback

Tylenchid 3-part StomatostyletFormed from wall of the stomaRhabdions fuse to form hollow styletBasal Knobs = from telorhabdions1 dorsal & 2 subventralShaftmesorhabdionsmetarhabdionsBarbprorhabdionsJ.D. Eisenback

Tylenchida StomaCephalicFramework(cheilorhabdions)BarbShaftBasalKnobsHoplolaimus sp.Stylet Protractor MusclesPlant ParasiteJ.D. Eisenback

elonolaimus longicaudatusJ.D. Eisenback

Nematode MorphologyCephalic Region = Stoma

Mononchus sp.PredatorMural ToothU. Zunke

AncyclostomacaninumDoghookworm

2-part Dorylamid OdontostyletDevelops as a sclerotized outgrowthin the esophagusBasal flanges = not “basal knobs”GuidingringStyletextensionStyletXiphinema indexU. Zunke

Dorylaimid Odontostyletwithout Basal FlangesLongidorusJ.D. Eisenback

Longidorus sp.OdontostyleGuidingringAmphidU. Zunke

Curved, Solid OnchiostyletDevelops from modified mural toothTrichodorus sp.

Solid, Curved Onchiostylet

Nematode MorphologyEsophageal (Pharynx) Region

Nematode Esophageal TypesKathy Merrifield

ESOPHAGEAL TYPES OF COMMON SOIL NEMATODESNoStyletBacterialfeederStomaProcorpusBarbShaftBasal knobsStomatostyletPlantpathogenProcorpusStyletStyletExtensionReplacementStyletOdontostyletPlantpathogenand virusvectorMedian bulb(Metacorpus)ProcorpusIsthmusBasalRegionIntestineIsthmusBasalRegionIntestineBasalRegionRhabditida Tylenchida Dorylaimida

Meloidogyne hapla femaleTylenchid3-Part StomatostyletBasal KnobsShaftBarbJ.D. Eisenback

3-part Tylenchid EsophagusIntestineProcorpusBasal regionslight overlapof intestineMetacorpus(median bulb)StomatostyletDitylenchus dipsaciU. Zunke

Belonolaimus longicaudatusShaft ofstomatostyletMetacorpusMedian BulbProcorpusBasal regionof esophagusR. S. Hussey

Meloidogyne incognita J2MetacorpusIntestineEsophageal glandoverlapping intestineProcorpusM.A. McClure

CriconemellaBasal regionof esophagusProcorpus fusedwith metacorpusJ.D. Eisenback

2-part Dorylaimid esophagus2-part Dorylaimid odontostyletOdontostyle(stylet)Odontophore(stylet extension)Lumen ofesophagusProcorpusof esophagusBasal regionof esophagusLongidorus sp.U. Zunke

Nematode MorphologyCardia = Esophageal-Intestinal ValveAntiregurgitationFunction

Nematode MorphologyIntestineIn posterior intestinenarrows to form a rectumHirschmann

Nematode MorphologyIntestine

Nematode MorphologyNervous Systemand Sense Organs

Nematode Nervous SystemNerve Cords-Dorsal-Ventral-LateralNerves-Papillae-Amphids-PhasmidsGangliaNerve Ring= Circumpharyngealcommissure

Nerve Ring Stained for Cholinesterase ActivityEsophagusFree-living NematodeJ.D. Eisenback

Nerve RingBasal regionof esophagusIntestine

Nematode MorphologyNervous Systemand Sense OrgansPapillae = touch, taste6 inner labial6 outer labial4 cephalic

Xiphinema americanumMouthPore-likeAmphid(taste)Lips (6 total)Papillae (touch, taste)C.H. Hopper

Nematode MorphologyNervous Systemand Sense OrgansAmphids = pouch with cilia and nerves-chemosensory-labial = on lips-sublabial = below lips on side of head-diverse in size and shape-no taxonomic significance-difficult to see in most plant parasites

Head of Meloidogyne cut open to reveal one oftwo amphids.

Stained amphid in Caenorhabditis elegansOliver Wagner

Nematode MorphologyAmphids

Meloidogyne hapla J2Pore-like AmphidJ.D. Eisenback

Desmodora pilosaMarineNematodeUni-spiralAmphidW. D. Hope

DorylaimopsisMarine NematodeSetaeMulti-spiralAmphidW. D. Hope

Nematode MorphologyNervous Systemand Sense OrgansPhasmids = scutellum-on side of nematode near tail-chemoreceptors-nearly impossible to see

Scutellonema brachyurumPhasmid

ScutellonemabrachyurumPhasmid stainedwith hematoxylinM.A. McClure

Nematode MorphologyReproductive System

Female Reproductive SystemOvaryGerminal zone = gamete formationGrowth zone = developing eggs, unfertilizedSpermatheca = stores sperm, fertilizes eggs asthey go byOviduct = connects ovary and uterusUterus = may contain fertilized eggsVulva = may be sclerified, easier to see,position along length of body is diagnosticGrowth Zone

Female Reproductive SystemNumber of OvariesMonodelphic = one ovary (B, C)Didelphic = two ovaries (D, E, F)Position of OvariesAmphidelphic = opposed ovaries, oneanterior; one posterior to vulva (D, E)Prodelphic = ovary(s) anterior tovulva (B, F)Opisthodelphic = ovary(s) posteriorto vulva (C)Post uterine sac = vestigial 2nd ovaryReflexed = ovaries folded (E, F)

Tylenchorhynchus sp. FemaleDidelphic, AmphidelphicVulvaVaginaUterusIntestineU. Zunke

Helicotylenchus sp.DidelphicAmphidelphicJ.D. Eisenback

Pratylenchus penetransMonodelphicProdelphicVulvaTheirry Vrain

Ditylenchus dipsaci femaleOvary stained with toluidine blueM.A. McClure

Structure of Nematode EggTrue Shell (chitin)Vitelline MembraneVitellusProteinaceous CoatFormed after egg leavesgerminal zone

Male Reproductive SystemTestisGerminal zone = gamete formationGrowth zone = for development ofspermatocytesSeminal vesicle = sperm storageCloaca = chamber where maledigestive and reproductivesystems joinSpicules = sclerotized copulatorystructureGubernaculum = sclerotized platethat supports spiculesBursa = Expansion of lateral field;forms flap that wraps aroundfemale during copulationMonorchic = one testisDiorchic = two testesReflexed = folded

Meloidogyne incognitaSpiculesOpeningto CloacaM.A. McClure

Belonolaimus longicaudatusBursaGubernaculumSpiculesSpiculesBursaJ.D. Eisenbach

Copulating Free-living NematodesFemaleVulvaMaleSpiculesJ.D. Eisenback

Nematode MorphologyTails

Nematode TailDistance from anus or cloacato end of wormShape and length may bediagnostic or notTailU. Zunke

Rhabditis sp.J.D. Eisenback

Nematode MorphologyEnd of Morphology Slides