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

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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

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