[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Fwd: Re: Did the K-T impact event seed Titan with life?

David Marjanovic wrote:

It should be mentioned that very, very few bacteria sporulate. *Bacillus*, *Clostridium*, and not much else. AFAIK magnetotactic bacteria don't sporulate.

You're right - so far no known magnetotactic bacteria are known to sporulate. But, given the phylogenetic diversity of magnetotactic bacteria, there's no theoretical reason why we couldn't have magnetotactic sporulating bacteria in nature. If such beasties exist, we haven't found them yet.

Anyway, I guess the meteorite was settled by bacteria after it had arrived in Antarctica...

Or, the magnetite was generated by some high-temperature physicochemically process back on Mars, without any biological input. That's my bet.

Phil Bigelow wrote:

The closest known Earth analog to the possible Martian meteorite bacteria
is a critter known as bacterial strain MV-1.  Magnetite produced by MV-1
resembles magnetite in *some* of those "fossil" blobs found in the Allan
Hills Martian meteorite (both in size and shape).

I hate to name-drop, but MV-1 and I are old friends, and I routinely grow MV-1 in the lab - along with several other magnetotactic strains (including my favorite, MC-1). I've co-authored papers on both MV-1 and MC-1, and both strains are going to be named fairly soon. Magnetotactic bacteria are extremely interesting in that they are one of the few kinds of bacteria that leave behind "hard-body" fossil remains, in the form of magnetite. And given that most of the magnetite is of a single-domain size, these bacteria are *extremely* important as magnetofossils, which is used in magnetostratigraphy.