Nhn sumaya enrichment_program
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Nhn sumaya enrichment_program






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  • Good morning and a WORM welcome to all. I said worms coz i will discuss about nematodes nematodes and nematodes.
  • Nematodes are classified according to where they live and what are their host...
  • Why nematodes
  • This is where our strength lies in ecological indicators and pollution studies....
  • How can Nematodes be used for pest management?There is a saying applied in biocontrol that “ the enemy of my enemy is my friend”Why? Because Entomopathogenic Nematodes (EPNs) in the genera Heterorhabditis (aka the cruisers since they look for their host) and Steinernema (aka the cruisers since they wait for their host)are used as biological control agent for diverse insect pests like Lipedopterans, Coleopterans, Dipterans and etc
  • During development to DJ, bacteria can be found in the vesicles (Steinernema) or anterior and middle part of intestine (Heterorhabditis)And there are about 200-2000 bacterial cells inside the EPNsThey are associated symbiotically with bacteria of the genera Photorhabdus and Xenorhabdus (Enterobacteriacae), respectively (Ciché et al., 2006). The bacterial symbiont kills the invertebrate host by producing toxins, exoenzymes and other metabolites (Dunphy & Webster, 1988; Bowen et al. 1998; Burnell, A. & Stock, P., 2000) approximately 24-48 hours after nematode invasion in the insect`s haemolymph (Simoes & Rosa, 1996). The bacteria proliferate while they supply appropriate nutrients for the nematode´s growth and development (Han & Ehlers, 2000). The dauer juvenile (DJ) is a free-living, third stage juvenile which is well adapted to long-term survival in the soil. It is also the infective stage that carries 200–2,000 cells of its symbiont in the anterior part of its intestine (Ehlers, 2001).
  • There are different stages in the life cycle:Phoretic phase – bacteria inside the DJPathogenesis phase- synergistic interaction which involves the nematode and the symbiotic bacteria for the death of the insect hostNematode reproduction- food supplyTo illustrate further, this is the Life cycle of entomopathogenic nematodes in infected larva of a scarabaeid beetle The dauer juveniles enter the host and the symbiotic bacteria are released – and that is phoretic phaseWhen the symbiotic bacteria are released and the insect dies after 24-78hrs, that is the Pathogenesis phaseAnd finally when the nematodes develop to adults and offspring exits from the insect cadaver, that is the Nematode reproduction
  • How could the Nematodes and Bacteria Kill the Insect Host? First, The EPN would penetrate inside the host insect thru the mouth, trachea, or the cuticle Right after the successful host penetration, the EPNS would recover from Dauer Stage to Infective StageThen, the symbiotic bacteria (Photorhabdus/ Xenorhabdus) will be released 3 h after penetration via the mouth of the nematode into the insect haemocoelAnd that will lead to the death of the host insect by the bacteria after 24-72hrs.The EPNS functions like a syringe, vectoring the bacterium into a sterile environment.
  • Alright, how are these EPN attracted by Insects?Epns are attracted by CO2 and vibrationsCO2 and vibrations triggers not penetration behaviour butPenetration behaviour is triggered by substances on insect cuticleAnother things is, the attraction by SOS signal caryophelene emitted by the plant when insects feed on the roots..That means when a Zea mays plant be infested by Diabrotica virgifera virgifera (the western corn borer), then the maize will emit a Save our Soul signal so Called CARYOPHYLENE to attract the EPNs.
  • Having said that , there are large scale producers for commercialisation of fresh dry EPNs namely: Bionema in Sweden, E-nema GmbH in Germany, Becker Underwood in UK, Andermatt in Switzeland and Koppert in Holland...
  • Entomopathogenic nematodes were successfully isolated by the research group.

Nhn sumaya enrichment_program Nhn sumaya enrichment_program Presentation Transcript

  • A “WORM” WELCOME TO ALL!!! Nanette Hope N. Sumaya
  • Entomopathogenic nematodes
  • Entomopathogenic nematodes
  •  ubiquitous  transparent body  conserved heat shock proteins  relatively simple organization  regulates the rate of decomposition and nutrient mineralization  most diverse and numerically dominant metazoans in aquatic and terrestrial habitats Why nematodes??? Nematodes with GFP photo by: NAMO group
  • Ecological indicators/Pollution studies Species Interaction studies Biological Control Agents Genetics studies Molecular studies recent applications:
  • Problems with residues? HIGH IN PESTICIDES
  • Analysis of Chemical Residue to Fruits and Vegetables sold in the German Market
  • Market contract with farmers
  • Comparison of data on performance of chemical and biological control IOBC / wprs OILB / srop From IOBC Internet book of Biological Control, Oct. 2006 http://www.iobc-global.org Lenteren, J.C. van, 1997. From Homo economicus to Homo ecologicus: towards environmentally safe pest control. In: Modern Agriculture and the Environment, D. Rosen, E. Tel-Or, Y. Hadar, Y. Chen, eds., Kluwer Acadamic Publishers, Dordrecht: 17-31
  •  Entomopathogenic Nematodes (EPNs) in the genera Heterorhabditis and Steinernema are used as biological control agent (BCA) for diverse insect pests. Family : Steinernematidae with 45 known Steinernema sp. Family : Heterorhabditidae with 11 known Heterorhabditis sp. The enemy of my enemy is my friend THE AMBUSHERS THE CRUISERS EPN pest
  • Bacteria can be found in the vesicles (Steinernema spp.) and anterior or middle part of the intestine (Heterorhabditis spp.) Ca. 200-2000 bacterial cells inside the EPNs. Killing of insect host larvae after 24-48 hrs by releasing exoenzymes, toxins or secondary metabolites Symbiotic relationship with the bacteria in the genera Photorhabdus and Xenorhabdus
  • 1. Phoretic phase -bacteria in the Dauer Juveniles 2. Pathogenesis phase -synergistic interaction 3. Nematode reproduction - food supply Different stages of the life cycle: 1. Phoretic Phase 2.PathogenesisPhase 3. Nematode reproduction
  • 1.Phoretic Phase: Bacteria well protected in the intestine of the dauer juvenile (DL) 2.Pathogenic Phase: Synergistic effects to overcome defence mechanisms of the host insect for establishment. 3.Saprophytic Phase: Bacteria supply essential growth factors during nematode development and reproduction
  • Penetration via mouth, anus, trachea or the cuticule of the host insect EPNs will recover from the arrested dauer stage Release of the bacteria (Photorhabdus/ Xenorhabdus) 3 h after penetration via the mouth of the nematode into the insect haemocoel Killing of the insect by the bacteria after 24-72h Nematode functions like a syringe, vectoring the bacterium into a sterile environment THE POWER OF TEAMWORK!
  • How are EPN attracted by insects? EPN are attracted by CO2 and vibrations CO2 and vibrations triggers not penetration behaviour but Penetration behaviour is triggered by substances on the insect cuticle
  • EPN Smart Enough to recognize their symbionts Heterorhabditis spp.
  • EPN Smart Enough to recognize their symbionts Steinernema spp.
  • Infection of Plutella xylostella via the Anus DBM- Cabbage Moth
  • Symbiosis: Nematode inhibits humoral defense against its symbiont • Insects produce small polypeptides (e.g. Cecropine, Attacine, Diptericin), which kill bacteria invading the haemolymph by lysis of their cell wall • DJs of S. carpocapsae produce a metallo-protease, that inhibits the production of the anti-bacterial peptides Cecropin • As a result the LD50 for Xenorhabdus nematophilus is much reduced • This is an active support by the nematode to protect its symbiont from the insect s defense
  • Life-cycle of EPNs in vivo and in vitro
  • Reproduction
  • Life Cycle of Heterorhabditis spp.
  • Endotokia matricida
  • Steinernematide DJs are determined in the sex – male and female Life cycle of Steinernema spp.
  • The use of EPNs: Steinernema spp. & Heterorhabditis spp. Sciarid Fly (Bradysia sp., Lycoriella sp.) Different Grubs Flower Thrips ( Frankliniella occidentalis) Sciarid Fly (Lycoriella sp., Bradysia sp.)
  • Becker Underwood , UK e-nema GmbH, Germany Bionema, Sweden Andermatt, Switzerland Koppert, Holland Being produced commercially in large scale bioreactors and used as biological control agents
  • Entomopathogenic nematodes were successfully isolated by the graduate research group of MSU-IIT. Currently, undergraduate students are now on the verge of finding nematodes with the propensity to infect agricultural pests. Pathogenecity tests will ensue after their preliminary experiments.
  • Artificial media preparation Rearing of the insect host, lesser wax moth Soil collection and nematode baiting White trap method