Small Things Considered

Why Be Intracellular and Be Motile?

by Elio | Why would a strict intracellular organism be motile? In the case of rickettsiae (and some not strict intracellular parasites such as the listeriae and shigellae), motility is carried out through the activity of the host's actin, apparently for the purpose of infecting adjacent cells. I am not talking about that, but rather I will consider here... Read more →

A Lakeside Tale

by Christoph Weigel | How small are bacteria ? And how big can they get as single cells ? For the lower end of the size scale, we know since the work of Jill Banfield's team that a multitude of ultra-small bacteria exist with a spherical diameters of ~0.25 µm and calculated cell vol­umes of ~0.009 µm³. Much larger are newborn cells of Escherichia coli  with a length of... Read more →

In the Beginning… there were Stromatolites

by Gillian Belk | Where can we find the first life forms on Earth? Although we do not yet know the exact microbes that managed to spin together some genetic information and make proteins, we do have evidence of life as far back at 3.5 billion years ago in what are known as stromatolites. Read more →

Old Enzymes Tell Stories

by Elio | Offhand, what can you say about the enzymes of the earliest cells? Surely, a few things pop up, for example, they were fewer in number and probably simpler than the ones we have now. They must have had fewer frills than the modern ones, which tend to have clear-cut tastes for substrates and... Read more →

Curioser and Curioser

by Elio | Curious indeed is an organism called Kakabekia barg­hoorn­ia­na. It is known to exist both as an ancient fossil and as a present-day cultivable creature. Just as curious is that it has been shuttled across the great biological divide, now to apparently having landed firmly in the eukaryotic camp. However, there still seems to be... Read more →

Accidental Complexity

by Christoph Weigel | You may wonder why you read the same motto twice in a week in STC but there's a reason. I will follow up Merry's recent post, her lucid description of in silico  and in vivo  experiments demonstrating that evolution can achieve complexity by small incremental steps if they confer... Read more →

Evolutionary Ways

by Merry Youle | Evolution skeptics point to complex biological features as evidence that the amazing intricacy of the biological world could not be the product of blind mutation. The de novo  creation of such com­­plexity, they argue, would require far too many coordinated mutational changes before the new form provided any fitness benefit. Thus, evolution simply cannot explain such apparent leaps. Evo­lutionists, beginning with Darwin, and continuing today, have posited that... Read more →

Who Dares Doubt The Decomposing Powers Of Fungi?

by David Lipson | Apparently, it is widely accepted that it took fungi 120 million years to figure out how to decompose woody plants. Hence lignin-rich materials accumulated along with the appearance of widespread forests in the Carboniferous Period, which led to huge coal deposits until white rot fungi finally caught up... Read more →

The Spell of Coxiella

by Elio | A few years ago, we celebrated one of the prettiest discoveries in modern microbiology, achieving the growth of Coxiella burnetii out­side its host cells in laboratory media (see Coxiella Escapes from Cell!). The excitement was justified, as this organism had been a prototype of a strictly intracellular organism. Best I know, it does not naturally grow outside of cells, despite having the ability to do so. Read more →

Making Genes from Scratch? Prokaryotes do too, after all

by Christoph Weigel | When bacteria add new genes to their 'fexible genome' by integration of a temperate phage they find themselves in the precarious situation of 'shared ownership'. Because, at any time or under stressful conditions, the phage can enter the lytic cycle. The phage then 'reclaims ownership' of its genes... Read more →