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covertjoy

Registered: 07/09/23
Posts: 272
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Clamp connections 1
#28454023 - 08/31/23 06:43 PM (4 months, 25 days ago) |
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Some questions regarding clamp connections and looking for clamp connections under the microscope.
1. Should there be a clamp connection at every septum?
2. Where in the mycelial network is the best place to search for clamp connections? Would it be close to the leading edge?
3. Do some dikaryons produce a higher density of clamp connections than others?
4. How does one differentiate between early clamp connections and early branching? I have observed that branches are often at a septum, as clamp connections are. Am I right in thinking that the septum only forms at the clamp connection when the clamp connection has made it's connection? Do clamp connections sometimes turn into branches?
For example which of the following are clamp connections and which are branching? My guess would be that only number 1 is a clamp connection?
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pablotx
pipette monkey


Registered: 05/06/23
Posts: 45
Loc: Hot & humid
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Re: Clamp connections [Re: covertjoy] 1
#28458453 - 09/04/23 02:02 PM (4 months, 21 days ago) |
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Great questions... I wanna know the answers too.
Are these photos 100x oil immersion?
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covertjoy

Registered: 07/09/23
Posts: 272
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Re: Clamp connections [Re: pablotx]
#28458455 - 09/04/23 02:06 PM (4 months, 21 days ago) |
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Quote:
pablotx said: Great questions... I wanna know the answers too.
Are these photos 100x oil immersion?
They are 40x LWD through the base of a petridish + shallow agar
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pablotx
pipette monkey


Registered: 05/06/23
Posts: 45
Loc: Hot & humid
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Re: Clamp connections [Re: covertjoy]
#28458528 - 09/04/23 03:29 PM (4 months, 21 days ago) |
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I gotta get me one of those LWD objectives. Thx.
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covertjoy

Registered: 07/09/23
Posts: 272
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Re: Clamp connections [Re: pablotx]
#28459077 - 09/05/23 01:49 AM (4 months, 20 days ago) |
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Quote:
pablotx said: I gotta get me one of those LWD objectives. Thx.
Make sure the objective has either a correction collar of 0-2mm or is configured for a coverslip thickness of around 1mm (as opposed to the usual 0.17mm). The correction collar is better.
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MagicDane
Experimenter

Registered: 09/19/23
Posts: 9
Loc: Denmark
Last seen: 2 months, 2 days
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Re: Clamp connections [Re: covertjoy] 3
#28475583 - 09/19/23 07:42 PM (4 months, 6 days ago) |
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1. I’m not 100% sure, but I don’t think there is a clamp connection at every septum. I’ve asked around, and the consensus was that a clamp only forms when the new cell ends up with 3 nuclei during division, and needs to send the duplicate backwards. Also all the texts (which weren’t many), say that “sometimes one nucleus is left behind in the new cell”. So basically, a clamp develops when an “accident” happens during division. I tend to agree with this assessment, because they seem rather rare when looking for them under a microscope, which indicates that they aren’t between every cell. But if someone finds information to the contrary, please let us know.
2. It depends on the stage of development the mycelium is. If it has colonized a whole bag/jar of grain, originating from spores of course, then just take a sample anywhere. If it’s two individual growths on a Petri dish, then take the sample from where the two growths have met and connected in the middle. If it’s like halfway colonized a jar/bag of grain, and you can’t differentiate between the two growths, then take the leading edge.
3. I couldn’t find any literature about the frequency of clamps forming in different dikaryons, but I would guess so if answer number 1 is correct. Then it would depend on how many “mistakes” happen during cell division.
4. Clamps develop when the septum between cells has formed or is forming, because that is where the issues of there being a duplicate nucleus in one cell arises. It can’t travel backwards anymore without a clamp. Clamps don’t form branches, but the apex of the hyphae does, which can be close to the septum, as the cell splits in two, which apparently can happen in a number of ways. It can make it look like the clamps are branching.
5. Number 1, 2 and 3 are definitely clamps in various stages of development. I’m pretty sure number 4 is as well, but it does look rather large. However, if it is a branch, then it’s definitely stunted in some way. I’ve attached a picture of how clamps can look in the different stages of development. I’m not entirely sure if I 100% agree with how/when a clamp develops on this picture, after having seen clamps under the microscope myself, and from what I’ve gathered from other sources. I think it’s a bit more complicated in real life. But it’s a good reference to see what a clamp looks like during different stages of development.
Edited by MagicDane (09/19/23 07:49 PM)
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