Trapping of Nematodes by Adhesive Branches of Monacrosporium cionopagum
This is a modal window.
The media could not be loaded, either because the server or network failed or because the format is not supported.
Formal Metadata
| Title |
| |
| Alternative Title |
| |
| Author | ||
| Contributors | ||
| License | No Open Access License: German copyright law applies. This film may be used for your own use but it may not be distributed via the internet or passed on to external parties. | |
| Identifiers | 10.3203/IWF/C-1871eng (DOI) | |
| IWF Signature | C 1871 | |
| Publisher | ||
| Release Date | ||
| Language | ||
| Other Version | ||
| Producer |
Technical Metadata
| IWF Technical Data | Film, 16 mm, LT, 110 m ; F, 10 min |
Content Metadata
| Subject Area | ||
| Genre | ||
| Abstract |
| |
| Keywords | ||
| IWF Classification |
Transcript: English(auto-generated)
00:14
Trapping of nematodes by adhesive branches of Monacrosporium cyanopagum.
00:23
A nematode less than one millimeter long has been trapped by a fungus. Fewer than one in a thousand fungi live in this predacious manner. Some of these fungi have evolved special trapping hyphae which are usually sticky.
00:52
One kind of sticky trap is found in the Deuteromycete Monacrosporium cyanopagum. These are called adhesive branches. They are unusually wide, short side branches.
01:11
This is a unicellular adhesive branch. It differs in morphology from a vegetative hyphae.
01:20
This electron microscope section through an adhesive branch shows a large number of small dark organelles arranged peripherally. These so-called dense bodies are characteristic of Nematophagus fungi with adhesive branches. Adhesive branches are mostly distributed in irregular groups over the mycelium.
01:41
The traps are at first unicellular and finally become two or more-celled. Phase contrast microscopy emphasizes the distinction between the adhesive branches and the mycelium. Adhesive branches may anastomose with each other.
02:02
In this way, simple ring-like structures develop. These simple rings are similar to the more highly differentiated adhesive traps of other Deuteromycetes. The adhesive branches function as traps when nematodes brush past them.
02:25
They then hold them firmly as seen here. The victim is firmly attached to the trap on the right. The animal pulls on the hyphae but these are resistant to breakage.
02:41
Despite the fact that the victim has touched the same adhesive branch at other points and the other branch to the lower left several times, it did not become attached to them immediately. Apparently the traps must first be activated. So that finally it becomes trapped to the left and also to the right at other places.
03:06
Escape of the trapped animal is now next to impossible, as illustrated by the bacterial feeding nematode Panagrelis redivivus. On this adhesive branch, a nematode belonging to a different genus has been trapped.
03:25
It is the fungus feeding nematode Afalencus avini. The victim is only attached to two cells of the branch. A young nematode is attempting to penetrate the trapping hyphae of the fungus and to suck out the contents.
03:42
But it has no chance of penetrating the thick cell wall. Why the young nematode on its part does not fall prey to the fungus is not clear. It is worth noting that the trap is not broken away by the vigorous struggling of the nematode.
04:05
The sticky material forms a meniscus around the surface of the trap. Despite the pulling strength of the nematode, the attachment is not broken. These pictures were taken by time-lapse. In the cells of the trapping organ, intensive cytoplasmic activity is observed.
04:25
Soon the movement of the nematode is paralyzed. Its tissues are dissolved.
04:42
New hyphae quickly grow out. A trapping hyphae is indicated outside the nematode and a digestive hyphae inside it.
05:01
In the following pictures, the adhesive branch is shown not in longitudinal but in transverse section. The fungus has already penetrated the nematode. An adhesive branch has broken through the nematode cuticle and has formed a spherical infection bulb in the body of the victim,
05:23
as seen here, using electronic contrast enhancement. About one hour has elapsed since the first contact. The fungus has made a narrow opening to penetrate the nematode's cuticle. The adhesive branch is therefore connected to the infection bulb by a fine hyphae.
05:44
An infection bulb is characteristic of predatory Nematophagus deuteromycetes. Further details from electron micrographs show that between the adhesive branch and the infection bulb, a septum has now developed.
06:02
The cuticle of the infected nematode and the adhesive material are also well shown. Now, at a somewhat lower magnification, a nematode is infected at the same time by two neighbouring adhesive branches and this is often observed.
06:29
Each adhesive branch has formed an infection bulb beneath the point of penetration. From the right-hand infection bulb, a nutritive hyphae has grown out.
06:42
The scanning electron microscope shows the spatial arrangement. The adhesive branch is here seen from above and therefore appears rounded in outline. The adhesive material is easy to recognise as a dark mass. Due to the great adhesive power of the sticky material, the nematode cuticle becomes indented before fungal invasion.
07:13
Penetration from another perspective shown for 21 hours. Here an infection bulb is just developing.
07:24
It swells and grows out into a nutritive hyphae. The nutritive hyphae lises and dissolves all the tissues of the nematode, as recognised by the lipid droplets in the hyphal cytoplasm.
07:47
Some hours later, the nutritive hyphae are growing freely. The trapped nematode has been completely digested as shown clearly by time-lapse cinematography taken over 36 hours.
08:06
The animal is paralysed. Nutritive hyphae invade, lysis follows. The digested material is transported from the nematode to the fungus hypha and there supplies nutrients for the growth of the mycelium.
08:44
Only a tangle of nutritive hyphae indicates the former presence of the nematode.