Bursaria truncatella, conjugation

Charles Krebs · Post by **Charles Krebs** » Sat Feb 16, 2008 10:59 am

I was going through some "old" samples and came across conjugating Bursaria. Their unusual shape makes for an odd configuration. During conjugation genetic material is exchanged but no new "individuals" are produced. A sort of "fountain of youth". The process is described in great detail here:
http://www.zoology.ubc.ca/courses/bio33 ... _cycle.htm
http://www.ciliate.org/conjugation.shtml

The third image is a single individual for reference.

olivier barth · Post by **olivier barth** » Sat Feb 16, 2008 11:31 am

wonderful pics, Charles!!!

bernhardinho · Post by **bernhardinho** » Sat Feb 16, 2008 11:33 am

Hi Charles

gorgeous and hardly ever seen!!

It must be la forza del destino that always the best photographers encounter the most rare and interesting motives!! When I try to take a pic of an interesting bird, I can be dead sure it'll show me its bloody tail for ten minutes before it decides to fly away.

But never mind

Thanks a lot!!!

Bernhard

rjlittlefield · Post by **rjlittlefield** » Sat Feb 16, 2008 11:41 am

Wonderful pictures!

I've been studying and studying these pictures, trying to understand the geometry.

With most ciliates, I think of the conjugating position as being "face to face" or "side by side". With linear shapes, this seems very natural, as it makes a whole line of corresponding parts come close together.

But these critters look curled up like one turn of a snail shell. That changes the whole affair! They're still "side by side", but with the curl, most corresponding parts do not come close together. Instead only two parts do, one near the "head" and the other half-way around from that.

I wonder where the actual exchange of nuclear material takes place?

--Rik

gpmatthews · Post by **gpmatthews** » Sat Feb 16, 2008 12:38 pm

Reminds me of a cabinet full of Klein bottles I saw in the Science Museum in London...

Frez · Post by **Frez** » Sat Feb 16, 2008 2:24 pm

That's incredible Charlie! You guys sure are catching the private moments today. Did you study this for any length of time after the shot?

Frez

MacroLuv · Post by **MacroLuv** » Sun Feb 17, 2008 8:26 am

Hey, incredible looking... like it has more than three dimensions.

Jean-marc · Post by **Jean-marc** » Mon Feb 18, 2008 12:17 pm

Waouuu !

Really wonderful Charles !!!

JM

Ken Ramos · Post by **Ken Ramos** » Tue Feb 19, 2008 3:57 am

What to say

I would have to echo everyone elses comments. Really supurb Charlie.

These things remind me of one of the "Goons" from the old POPEYE cartoons.

Hairyduck · Post by **Hairyduck** » Tue Feb 19, 2008 11:08 am

What sort of stop are you using for your darkfield Charles? Or are you using a dedicated condenser?

Darkfield on my Olympus has always been a very hit and miss affair!

Fantastic images... again

Kev

Charles Krebs · Post by **Charles Krebs** » Tue Feb 19, 2008 9:38 pm

Thanks all!

Kev...

What sort of stop are you using for your darkfield Charles? Or are you using a dedicated condenser?

The condenser I use has a rotating turret with circular openings that will take either a DIC prism or a phase contrast annulus. I cut a clear circular plastic disk to fit in one position, and then attached a round opaque paper circle to it's center. I tried several sizes until I had one that worked with the 4X and 10X. Since my 20X is a 0.70 NA and my 40X is a 0.95 NA I'll go to an oiled darkfield condenser if I want to use them. (I have an old Zeiss one that I have adapted to fit the Oly). For shots like the exposure is very critical. It is very easy to overexpose these if you are not careful.

Frez...

Did you study this for any length of time after the shot?

When I first saw these they were in one of my "large" sample bowls. I carefully put them on a slide but was wary of trying to place a cover slip over them. So I first took a few images with a 4X and the water just "pooled" on the slide with no cover (these shots). After I had a few I tried to add a cover slip, but even though I kept the slip "lifted" as soon as it contacted the water they separated.

Hairyduck · Post by **Hairyduck** » Tue Feb 19, 2008 11:16 pm

Thanks for the insight Charles, I'll have to try something similar, the issue I have is that the dic condenser I have is the one with the fixed prisms and phase annuli so could be a little interesting...

Charles Krebs · Post by **Charles Krebs** » Wed Feb 20, 2008 12:06 am

Kev...
Can't you get good darkfield (at least with lower power objectives) by using a built-in phase annulus (probably the one for 100X)?

In a way that is really all I am doing.

Hairyduck · Post by **Hairyduck** » Wed Feb 20, 2008 11:41 am

I do get a result from the annuli but it's not that great. I have high na objectives too which may not be helping

Charles Krebs · Post by **Charles Krebs** » Wed Feb 20, 2008 12:47 pm

Kev,

I have high na objectives too which may not be helping

I think that is a part of the "problem". As wonderful as very high NA objectives are (generally they are Apos's and wonderfully color corrected as well), I find them difficult to use for darkfield unless the subject is extremely thin and positioned flat to the cover slip. Whenever I try darkfield with my 40/0.95 I think how nice it would be to have a 40/0.65 Plan Apo for this use. The best darkfield I have done with my 20/0.70 was when I rigged a makeshift "funnel stop" at the rear and photographed at a slightly reduced NA.