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Bio Of Paras

by: Emerald Funk

Bio Of Paras ENT 156

Emerald Funk
GPA 3.93


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This 26 page Class Notes was uploaded by Emerald Funk on Tuesday September 8, 2015. The Class Notes belongs to ENT 156 at University of California - Davis taught by Staff in Fall. Since its upload, it has received 18 views. For similar materials see /class/187643/ent-156-university-of-california-davis in Entomology at University of California - Davis.


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Date Created: 09/08/15
ENTOMOLOGY 156 BIOLOGY OF PARASITISM Topic 3 Nematode Structure amp Function 1 3quot g l Head modifications Male tail Nematode Structures amp Functions to Cover Cuticle Hypodermisepidermis Body musculature Molting Alimentary tract Reproductive systems Sensorynervous system I Nematode Cuticle Functions of Cuticle 0 Protection from environment e g host digestion 0 Structural integrity and role in hydrostatic skeleton function A General Characteristics of Cuticle Variable thickness 02750 uM Varies wspecies Noniliving analogy human fingernails Mainly produced by epidermishypodermis exceptions some cuticle in mouth stoma Permeable small molecules ions water can move across Can grow between molts unlike arthropod exoskeleton B Composition of Cuticle Primary proteins are collagens Collagens can be stageispeci c Lipids carbohydrates glycoproteins inon the outermost layer epicuticle Not homogeneous layers No chitin unlike arthropod exoskeleton C Structure of Cuticle 3 Major Layers Zones outside body Seeemenma or hypodermis D Structure of Cuticle 0 Medial amp basal zones Medial ZOHC SPOHgY appearance in TEM Sometimes absent outside body cortex m HHWH l J J W hypodermis asal zone many electrondense Fibers Imparts strength E Cuticular Surface Modifications Things of great beauty but functions often speculative Annulations Longitudinal ridges Alae Spines I L Inflations Cordons 99159 E Cuticular Surface Modifications l Annulations transverse lines in cuticle Assist in bending possibly other aspects of locomotion 4 Light microscope View AnniE Magn WD I5Cll2V WEHQX 13D 9139 E Cuticular Surface Modifications 2 Longitudinal ridges the synlophe of certain vertebrate parasites Trichostongylidae Help maintain position in intestine Nematodirus spp cuticular ridges synlophe Jill M E Cuticular Surface Modifications 3 Alae Wings projections of cortical amp medial cuticle cephalic 3 a quot alare m i 39j Caudal alae part of male bursa E Cuticular Surface Modifications 4 Spines present in vertebrate parasites and some free living nemas Functions Holdfasts vertebrate parasites and anti predator defenses free living species Seuratia a vertebrate parasite Chronogaster a free living nematode E Cuticular Surface Modifications 5 lnflations blister like swellings in some vertebrate parasites Functions Allow head movement when buried in tissue Oesophagostomum An intestinal nodular worm E Cuticular Surface Modifications 6 Cordons present in a few vertebrate parasites Function Similar to inflations gt cordons ll Nematode Hypodermis or Epidermis A Basic Hypodermis Structure 0 Thin 2080mm except at cords not illustrated to scale 0 Cellmembrane bound 0 Syncytial in adult Secernentea 0 Nuclei of cells in cords 0 Cords run length of worm 0 Produce cuticle Arcade Cells Specialized Hypodermis CAENORHABDITIS ZELDIA chailnrhabdlon pmrhabuson en a mesarhabdian melamabdlon telnrhabdinn B Functions of Hypodermis Responsible for cuticle synthesis amp structure and somehow much of body shape Active exchange of water and small molecules Formation and dissolution of cuticle molting Anchors body muscles to cuticle through tonofilaments M gtWN Production and secretion of some pheromones eg sex pheromones in sedentary plant parasites A 111 Main Body Muscles of Nematodes Basic Structure Spindle shaped longitudinally oriented Attached to the hypodermis and via hypodermis to cuticle Divided into 4 fields by hypodermal cords Alternate dorsalventral contractions give nemas sinusoidal movement ventral dOT 31 N Main Body Muscles of Nematodes Basic Structure 3 parts to muscle Contractile region contains actin and myosin Noncontractile region includes nucleus mitochondria glycogen stores Innervation processes goes to nerve cord rather than an axon of motor nerve to muscle INNERVATION PROCESS HONCDNTRACTILE REGION Body Muscle Cells Showing Innervation HUCLEUS EPIDEHMIS From Bird amp Bird 1991 III B Somatic Muscle Cell Types Platymyan39an smaller nemas Sarcomeres close to hypodermis n llm Platymyarian Coelomyan39an larger nemas like Ascaris Circomyarian rare type Circomyarian y V Coelomyarian Note One species may have multiple types During development one type may be replaced by another Review of Nematode Cross Section C Specialized Muscles Some examples Stylet protractor muscles quot umphidial opening 67 framework blade Stylet cone hypodermi s stomntal opening vestibule Stylet protractor ll Stylet protractor 1 stylet Margit membmnous fold protractor 8 Secondary mu5cle Stylet Shaft elem stylet knob esophageal lumen 7 Somat39C quotquot5019 nonconlraclile portion of Stylet protractor Specialized Muscles esophagus H c IIA 3939gtr39 I V 39 I K V V XIPHINEMA i 4 N VE 39 L EN ER UM H RADIAL MUSCLES r RETRACTOR MUSCLES XIPHINEMA LUMEN l Wl NERVE 7 i RADIAL MUSCLES RETRACTOR MUSCLE S IV Molting in Nematodes 0 A crucial process With potential for control 0 4 molts each may take from hours to days 0 Molt involves cuticle of body wall lining of stoma amp esophagus rectumCloaca excretory duct ducts of glands HOW Many Molts in Egg 0 2 for most Secernentean vertebrate parasites 1 for most Secernentean plant parasites 0 for most Adenophoreans n v 2 quotr l J gm quot C quot Larva within egg quot 39 51 V Alimentary Tract 0f Nematodes Lined with cuticle Composed of muscles glands nerves Intestine 7 nutrient absorption lipid storage Waste excretion Rapid movement of materials Anus females cloaca males 1 Stoma buccal capsule Stomal variation 0 In shape 0 In structure of cuticular lining rhabdions In armature teeth denticles stylet In muscle attachments Stomal Variation in Different Parasites Chabertia mucosal feeder Hoplolaimus Plant parasite With stylet Ancylostoma Blood feeder Terminology for Stoma Basic Chambers of the Stoma Surrounded by rhabdions I l cmmmm of body wall origin gymnastom Surrounded by rhabdions of various origins arcade cells muscle cells stegost om surrounded by esophagus Surrounded by rhabdions of esophageal origin Rhabdions of Stoma LM nonema ll 2 Esophagus pharynx G S Paracrobeles Esophagus pharynx 0 Structure basis for much evolutionary speculation about nematodes Most complex nematode structure muscle epithelium nerves glands cuticle Structure particularly muscle development related to nematode feeding type 0 One dorsal gland 2gt subventral glands Structure of Nematode Esophagus Procorpus Metacorpus Median bulb 39 Isthmus I sndloo Postcorpus W glands End bulb basal bulb Cllnq Due 12 3D Representation of A w 7 g STOMATOSTYLET I W Plant Paras1te Esophagus FHARVNSEAL ELAN MVOW Dorsal I K Subdorsal Subventral sua VENTRAL PHARVNGEAL GLAND Ventral Cross section of Esophagus Basal Bulb Overlap Glandular Development Plant parasites may have basal bulb overlap of intestine f A K 39 H Overlap can be ventral or dorsal dependlng On which glands are overdeveloped Dorsal gland in plant parasites involved in feeding In some secretions cause giant cell formation WO Overlap Intestine of Nematodes Intestine nutrient absorption energy storage waste excretion Intestine of Nematodes Begins Where cuticle lining stops 0 Single cell layer thick 0 From 20 to one million cells 0 Usually unbranched but may have a pouch caecum With specialized functions eg Steinernema spp Have caecum that holds bacteria Intestine of Nematodes Ascaris Cross section Ascaris intestine Structures at increasing magnification TERMINAL W was 39 1quot BASAL LAMELLA Functions of Nematode Intestine 0 Absorption of food digestion although in some nemas this occurs outside the intestine 0 Food storage lipid globules up to 50 of intestinal volume 0 Excretion of wastes note excretory secretory system not really excretory VI Reproductive Systems amp Reproduction Some facts 0 Nematode eggs same size range 50 100 um regardless of adult worm size 0 Amoeboid sperm 0 Tubular epithelial lined gonads 0 Most species amphimictic 0 Egg output greatest in vertebrate parasites eg Ascaris 200000 per dayfemale B Reproductive Structures of Female 7 Postivulval sac i 39 15 Variation in Gonad Length amp General Shape SHORT LONG REFLEXED COILED Male Reproductive System H EAD Monorchic Diorchic Vesicula seminalis Vas def erens r TAIL Most Secementea monorchic Most Adenophorea diorchic Cloaca amp Male Copulatory Structures Caudal was Spicules no true lumen for Sperm transfer Capitulum A Gubernaculum V Gubernaculum 16 Some Characteristics of Male System Cloaca common opening for digestive and reproductive systems Vas deferens often muscular also glandular Spicules usually paired rarely absent Gubernaculum fairly common lines dorsal side Capitulum more rare lines ventral side Male Copulatory Structures 3975 Cervidellus sp spicules Nematodirus Haemonchus Nematode Amoeboid Spermatozoa Mitochondrion o 39 t39on of movement 39 o Cellbody Nucleus O Pseudopod i quot y lo 0 Fiber r O L V 3900 complex I y 39 39 z 39 0 3 Membranous 39 organelle Ascaris sperm VII Nematode Nervous Systems 1 Central nervous system 0 Nerve ring surrounds esophagus 0 Ventral nerve cord runs Within ventral hypodermal cord 0 Dorsal nerve cord runs Within dorsal hypodermal cord 0 Nerve cords innervate body wall muscle Ner e ring 2 Sympathetic involuntary nervous system 0 Esophagosympathetic operates esophagus 0 Rectal Sympathetic controls defecation Sensilla Nematode Sensory Receptors 0 Sensillum name for nema sensory receptor A receptor nerve plus non nervous supporting cells glial cells 0 Nematode sensilla similar to insects 0 Concentrated in head and tail of nemas E g Papillae phasmids amphids deirids r C t Socket 1 3 3 i Bas1c Structure of I III C611 39 2 a Mod1f1ed 1 J cilia Sens111a 3 Cells Long L c it IJT39 Sensory cell Wdendrite Sensory Cell 18 3 Main Nema Sensilla Types 1 Papillum appear as bump on cuticle surface 1 2 neurons per papillum mostly mechanoreceptors no opening to outside 0 some chemoreceptors pore leading to outside 0 papillae may be on stalk Adenophorean setae 0 most papillae on head and tail of nemas Enface View of Typical Nema w Papillae OWE J LABIAL NSILLUM I v F SENSILLUM CEPHALIC INN Fl LABIAL SENSILLUM Structure of Mechanosensory Papillae OUTER LABIAL SENSILLUM 4 EPIDERMIS SOCKET quot N SENSILLAR POUCH quotnullquot SHEATH CUTICLE DENDRITE l9 3 Main Nema Sensilla Types 2 Phasmids sensilla in Secernentea tail 0 Located in lateral field paired 0 Opening often difficult to see 0 One neuron per phasmid probably chemosensory A stained I opening 3 Main Nema Sensilla Types 3 Arnphids found in both classes Located laterally in head region Openings range from small to large amp complex Many dendrites per amphid Multiple known functions detect volatile odorants detect aqueous attractantsrepellents a thermoreceptors Amphid Structure F Dendrite tips 5 a Tight j nction Pocket cell Finger dendrite thermoreceptor Tight junction Wing dendrite volatile odorant detector General sensory a dendrites 20 NervousSensory System of Nematodes I Major advances from studies of C elegans 7 Complete reconstruction of Ce nervous system 7 Studies of behavioral mutants 7 Laser ablation functional studies 7 Zapping neuron cell bodies How has Ce informed us about parasite neurobiology Strangylaides nerve cell bodies I v 39 Dauer Pathway in Cuennrhubdit39n eleguns Amp 39 neurons detect dzuer hormone 9 L2d gt Dauer Egg gt L1 L4 gt Adult L2 gt L3 Adults producing oaucr normonc 21 Strongyloides stercoralis Life Cycle Flmltl Adult 5 Pauli mm Hh di lnrm LIN Fll a fuml Lawn A UTDI39HFEQHUE EVELE quot mh 539 39 Larvae HDET EKTEERHAL EWIHUHHEHT Filarifm Lam CELE Larva Larvae HE TEHDEIDMIE CVCLE If Fthahd nnn39 r luwae Fl39llrll urm 1 I Fragilan Adullage Based on Blaxter et al 1998 Figure Dorris et al 1999 Nematode Phylogeny According to SSU rDNA 1ooI 93 I F39Eli39liigE Oiamli ae 39 100 Hillii I s l39 quotj Cephalobidae 4 Aphelenohida 5 f Tylenchida f Oxyurida Ag Spirurida Aug Ascaridida Ag Rhigonematida Iv Chromadorida 5 23 Enoplida is g Trip0nchida Ef Trophic ecology 5 Bacterivore Algivoreomnivore I Dorylalmlda f I predator i m 52 Fungivore Mermithloa I v I I I f Phytoparasite Trlchocephalloa 5 Entomopathogen I momoncmda 1 Invertebrate parasrte Vertebrate parasite Strongyloides stercoralis Life Cycle Final Adult 5 I Lin J UTD HFEGH FE C FELE i 39 in i a 39lunnLIr E I n n 39 FilaannwnLnNma bd il ann Lanna EVELE Larva 39 Lamar HETEEDEIDHIE E FELE l HDST r I I I I 1 Is larval switch like C elegans dauer I development Fi39lr m 7 i Huntde Lama 139 lungs Eillrll nrrn 1 EllHIM lel m Adults r 22 Nerve nng laser ablation of ASF amp Asr causes larvae to Ewrtc homogonrc cycle In Ce the h S stercamlis Nerve Cell Bodies mologous nerve cells control dzuer formation Do Nematodes Have Ecdysone What evidence from Nuclear Receptor Genes Nuclear receptors I Transcriptional regulators in metazoans I Characterizedb quot quot 39 I At least some modulated by binding of ligands eg hormones 23 xx x x X X NR Structure EC x g o X x E n X amp FUHCtlon xcZncGKG FHWRmxfgxoZ ox XXXXCXXXGM NB CD E DNA binding Hormone binding Activation Dimerization bi Nucleus gt Ligand 1 are l g iquot39 7quot Cytoplasm J From Sluder amp Maina 2001 Trends in Genetics 17 206 l NRs and Insect Molting 20hydroxyecdysone EcR UTsp Activation of i transcriptional 2 regulatorsincuding l F orphan NR5 l Molting EcR NR Orthologs in Nematodes beG02P14 E CeNHRB CeDAF12 M MLSsNHRi quot CeNHlRe48 DmHR96 HsPXR HsVDR DiDir0filaria immitis 39 39 DmECR DmDr050phila HSFXR melanogaster BmNHRB 0vNHR 1 39H TRU HSH0m0 sapiens BmBrugia malayi 24 Usp NR Orthologs in Nematodes DmDr050phila melanogaster DiDir0filaria immitis HsH0m0 sapiens m HsNGFle CeNHR6 NR4 quot MiNHRB Nematodes And Ecdysteroids Caenorhabditis elegans Nematodes With ecdysteroids No EcR or Usp Nuclear Dirofilaria Ascaris Receptors Onchocerca No ecdysteroid production Nematodes identified With No response to ecdysteroids ECR or Usp 111 NR5 Dirofilaria amp Brugia Nematode 93 V j9 is 1 According to SSU rDNA Cephaiobidae 1339 100 a quotTM v a any 39 Hag 13 Apheienchlda I Oxyurida Ag A Spirurida Ag Ascaridida 5 Rhigonematida Based on Blaxter et a1 1998 Figure Dorris et a1 1999 I Chromadorida 35 a Enoplida If Triplonchida Big Trophic ecology 52 Bacterivore 639 Algivoreomnivore Dorylaimida f g predator a Fungivore Mermithroa rrchocephahoa Ag Entomopathogen quot1 MOHOHCh39da 1 115 Invertebrate parasite g Vertebrate parasite f Phytoparasite Orphan NRs In The Molting Cascade HsRAR quot quot quot 2 HSRARg HS Homo saplens CeNHR 23 DmHR3 Ce Caenarhabdms elegans HsR ORa szDmsaphila melanagaster DmF3939ZSFF11 S DmHR39 What Conclusions About Nematode Molting and Ecdysone 26


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