Infection of Nematodes by Hourglass Traps and Conidial Traps in Nematoctonus spp.
This is a modal window.
Das Video konnte nicht geladen werden, da entweder ein Server- oder Netzwerkfehler auftrat oder das Format nicht unterstützt wird.
Formale Metadaten
| Titel |
| |
| Alternativer Titel |
| |
| Autor | ||
| Lizenz | CC-Namensnennung - keine Bearbeitung 3.0 Deutschland: Sie dürfen das Werk in unveränderter Form zu jedem legalen Zweck nutzen, vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen. | |
| Identifikatoren | 10.3203/IWF/C-1873eng (DOI) | |
| IWF-Signatur | C 1873 | |
| Herausgeber | ||
| Erscheinungsjahr | ||
| Sprache | ||
| Andere Version | ||
| Produzent | ||
| Produktionsjahr | 1992 |
Technische Metadaten
| IWF-Filmdaten | Film, 16 mm, LT, 93 m ; F, 8 1/2 min |
Inhaltliche Metadaten
| Fachgebiet | ||
| Genre | ||
| Abstract |
| |
| Schlagwörter | ||
| IWF-Klassifikation |
Transkript: Englisch(automatisch erzeugt)
00:16
Infection of nematodes by hourglass traps and conidial traps in nematoctonous species.
00:33
Certain fungi feed on small soil animals, especially nematodes. Here, a nematode is caught on a specialized mycelial trap.
00:42
The fungus is said to be predatory. Conidia of the same fungus are attached by adhesive to another nematode. The fungus is here behaving like an endoparasite. Species of nematoctonous show both kinds of behavior.
01:03
The conidium of nematoctonous lyosporus has here germinated to form a short apical germ tube. The spore itself is obclavate. It has germinated to form a short germ tube which bears an hourglass trap.
01:26
The trap surface is covered by adhesive. By means of this adhesive, the spore attaches itself to a passing nematode.
01:41
Within a few minutes of becoming trapped, the behavior of the nematode changes. Its movement is slowed down, possibly as a result of a toxin secreted by the spore. Increasing paralysis leads to its death within one or two hours.
02:03
The fungus develops traps not only from its spores, but also from its mycelium. The traps, like those on the spores, are also hourglass-shaped and surrounded by adhesive.
02:21
If a nematode comes into contact with a mycelial trap, it becomes firmly held. The branching mycelium of nematoctonous concurrence grows into the air and from it conidia also develop.
02:45
Under a coverslip, the spores germinate to form normal hyphae. The hyphae branch to produce mycelia. When conidia germinate on an agar surface without a coverslip,
03:02
the germ tube remains extremely short and ends in a trap. The spore thus becomes infective and is termed a conidial trap. The trap is also hourglass-like.
03:20
Under a coverslip, the trap may grow out to form a normal hyphae. A clamp connection is developing. Conidial traps thus represent sporelings with an extremely reduced mycelium.
03:40
On a dry, agar surface, most spores have germinated to form conidial traps. The sticky traps do not lie on the substrate but point upwards away from it. This nematode larva is too thin to make contact with a trap.
04:03
In contrast, an adult nematode has no chance of avoiding contact.
04:26
Once spores have become attached, a nematode cannot release itself from them.
04:46
The adhesive material brings about close contact between the trap and the cuticle of its victim. Another member of the same genus is Nematoctonus robustus.
05:01
Its conidia are sausage-shaped. The clamp connections on the mycelium indicate that Nematoctonus is a dikaryotic basidiomycete. In this third species of Nematoctonus, two developmental pathways are also possible.
05:20
The conidium in the middle has produced an adhesive trap, whilst the others have formed hyphae. On the hyphae, hourglass traps have developed. In contact with one, a nematode has been trapped.
05:40
Sometimes one breaks free from the mycelium but not from the trap. Usually, despite all its struggles, the nematode is firmly trapped onto the mycelium. As when trapped by an adhesive spore, the victim shows increasing paralysis.
06:09
By time-lapse cinematography, we see how a hyphae attracted towards a nematode fails to penetrate it because it has no attachment structure.
06:31
The penetration of the victim is by hyphae which develop from adhesive traps. Following successful penetration of a nematode, trophic hyphae branch and fill its body.
06:46
The substance of the captured nematode is enzymatically dissolved to provide nutrients for the development of an external mycelium. Outwardly extending hyphae first form a rounded bulb before developing further.
07:03
The exit point is thus restricted, possibly so that dissolved materials cannot escape, whichever method of capture is adopted, the later stage of exploitation is the same.
07:22
Finally, after about four days, most of the body contents have been absorbed and the nematode cuticle collapses. The dead animal thus serves as a nutrient source for the fungus.