Peranema eating a dead rotifer

[Wes]

I was able to witness the voracious appetite of Peranema in this case nibbling at the corpse of a dead rotifer (almost certainly crushed by the coverslip due to evaporating water). You can clearly see the rod-like organ (visible as two parallel tubes at one end of the cell) and the way its pushed forward into the rotifer to facilitate uptake of tissue bits. On one occasion I saw 7 Peranema individuals inside the remnants of a long gone rotifer feasting on bacteria. I've attached a short image sequence to get a better idea of its feeding behavior.

[75RR]

Very nice detail!

Would be useful if you added some information on your images - objective, technique, size etc... I like to guess, but as in crosswords, it is always nice to confirm ;)

"Peranema is capable of ingesting a great variety of living organisms provided these
are motionless. Small organisms are swallowed whole; larger ones are either engulfed
or cut open by the rod-organ and their contents sucked out. The rod-organ can be
protruded out of the cytostome and used in holding on to, and cutting, the periplast
of the prey".

Y. T. CHEN
Journal of Cell Science 1950 s3-91: 279-308

https://jcs.biologists.org/content/s3-91/15/279

[Wes]

Thanks 75'. Peranema itself measures at around 50x38µm but that changes a lot as it keeps changing its shape (when its moving in one direction it becomes more cigar-shaped). Technique is DIC and I used 40/0.95 apochromat objective for all images.

This is an excellent review that you linked to. I suspect one of the reasons why I got such an abundant Peranema population in my culture is because I was throwing random things in it, one of which happened to be milk. Peranema loves milk (according to the same review).

[mintakax]

Beautiful images Wes and they quite nicely show the feeding mechanism ! Thank you 75RR for the extra info, I had no idea this was such an opportunistic feeder.

[Sauerkraut]

More excellent DIC images and it's always educational to see the behaviors of these microbes. To me the behaviors are more interesting than the identification most of the time and it's fascinating to see how microecology seems reflective of macroecology. Or vice versa, more accurately, since the microbes were here first.

[Wes]

Thanks mintakax and Sauerkraut. I was quite surprised to see Peranema biting the dead rotifer, from what I read it sounds like they are chemotactically attracted to the delicious juices of the freshly squeezed rotifer. Sometimes it really feels like I'm going on a microscopic safari.

[Wes]

I just observed two Peranemas gang up on a recently deceased rotifer. One of them stuffed its flagellum inside the dead body and used it like a kitchen mixer to swirl around the contents. Couple of minutes later the other Peranema protruded its rod organ and bit off the rotifer's eye and took off with it!

Sorry I know there are no pictures or videos but I just had to share this observation with you guys. This is by far the most brutal thing I've seen recently

[mintakax]

I just observed two Peranemas gang up on a recently deceased rotifer. One of them stuffed its flagellum inside the dead body and used it like a kitchen mixer to swirl around the contents. Couple of minutes later the other Peranema protruded its rod organ and bit off the rotifer's eye and took off with it!

Sorry I know there are no pictures or videos but I just had to share this observation with you guys. This is by far the most brutal thing I've seen recently

Its a "dog eat dog" world out there

[mnmyco]

You should try to stain the rotifers with a very weak solution of Congo red and then feed it to the Peranema. You should be able to watch the color change due to the pH. I have down this with yeast and paramecium for an intro bio lab. The students didn’t see much though as they a rather poor at using microscopes intro bio.

MNMYco

[Wes]

Great idea mnmyco! So the yeast should turn blue when the food vacuole containing them gets acidified?