Moselio Schaechter


  • The purpose of this blog is to share my appreciation for the width and depth of the microbial activities on this planet. I will emphasize the unusual and the unexpected phenomena for which I have a special fascination... (more)

    For the memoirs of my first 21 years of life, click here.

Associate Bloggers



  • (Click photo for more information.)

Bloggers Emeriti


  • (Click photo for more information.)

Meetings & Sponsors



« A Call From Arms | Main | Location, Location, Location »

August 20, 2009

Talmudic Question #52

by Mark Martin

Given the ubiquity of intracellular associations between eukaryotes and prokaryotes, why are there so few reports of prokaryotes living "within" prokaryotes? In fact, I can only think of one reported case.

Comments


Oh, I love the idea of Daptobacter, and I am sure that there are beasties like that out there. But the problem is that no one has yet cultivated the organism (or, at least, has published on it and is willing to distribute it to other researchers). It is a very tough issue to show predatory behavior solely from EM. But there are many more tools available now: look at the fine work with Nanoarchaeum and Igniococcus.

So I look forward to seeing more "types" of predation cracked with microbial systems that we can study in lab.

Regarding /Daptobacter/, I recommend you the article "Bacterial symbioses. Predation and
mutually beneficial associations" by Isabel Esteve and Núria Gaju.

http://www.im.microbios.org/06june99/06%20Esteve.pdf

A description of a Aug. 20th Nature paper that is related to the topic. The endosymbiosis involves actinobacteria and clostridia.

Cheers,

Robert Jung

http://www.sciencedaily.com/releases/2009/08/090819135436.htm

Elio says:
Thanks for pointing out the Lake paper. We hope to see it reviewed in these pages at some point.

Jonathan, I would very much like to tell you that Daptobacter can be grown in culture. I haven't seen any evidence of this, nor has anyone I know published on such an event. I would love to see high school students look for predatory bacteria from all kinds of sources, and surely such an interesting "undomesticated" beast would show up.

I worry about "predators" identified solely by EM. But then, I was trained as an old school (pre-genomics---I don't understand your business very well, I am shamed to admit) geneticist, to whom phenotype is everything.

As for the periplasm, I admit freely it is a unique compartment. Maybe the best approach is to search for predators of Gram positive bacteria? We would probably find "peptidoglycan surfers"!

Edouard Jurkevitch and his coworkers have an interesting model, where the intracellular "invader" provides some advantage to the larger bacterium. I would love to see such an arrangement! And to borrow and modify from J.B.S. Haldane, the microbial world isn't stranger than we imagine. It is stranger than we *can* imagine.

I love topics like this! Alas, I have nothing useful to contribute, but I wanted you to know that this post is highly appreciated nonetheless.

I guess predatory bacteria like Bdellovibrio don't count as "within", as they are in the periplasmic space? Although, supposedly there are predatory bacteria such as Daptobacter that actually enter the cytoplasm, although I think somebody (maybe even Mark Martin) told me that nobody has managed to grow it since Margulis' initial description.

How slightly tragic that I comment on my own posts! Anyway, a couple of recent articles that are relevant to this discussion that I missed early on:

Davidov Y, Jurkevitch E. (2009). "Predation between prokaryotes and the origin of eukaryotes." Bioessays. 31:748-757.

and...

Vesteg M, Krajcovic J. (2008). "Origin of eukaryotic cells as a symbiosis of parasitic alpha-proteobacteria in the periplasm of two-membrane-bounded sexual pre-karyotes." Commun Integr Biol. 1:104-113.

My guess is that, as we look deeper, we will find other examples of "prokaryotes within prokaryotes."

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been saved. Comments are moderated and will not appear until approved by the author. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment

Comments are moderated, and will not appear until the author has approved them.

Teachers' Corner

Podcast

How to Interact with This Blog

  • We welcome readers to answer queries and comment on our musings. To leave a comment or view others, remarks, click the "Comments" link in red following each blog post. We also occasionally publish guest blog posts from microbiologists, students, and others with a relevant story to share. If you are interested in authoring an article, please email us at elios179 at gmail dot com.

Subscribe via email

Translate




Search




MicrobeWorld News

Membership