On 23/05/2011 14:58, David Paste wrote:

Right. Really? I mean, really? Bugs build up a resistance to peracetic
acid?!


I'll be surprised if they don't. Give them enough time, and a
growth-limiting but non-lethal dose, and they'll be away. Such
conditions will be found in the local drains if nowhere else.

Have a read on http://en.wikipedia.org/wiki/Extremophile

Andy

On May 29, 8:56*pm, Andy Champ wrote:

I'll be surprised if they don't. *Give them enough time, and a
growth-limiting but non-lethal dose, and they'll be away. *Such
conditions will be found in the local drains if nowhere else.

Have a read onhttp://en.wikipedia.org/wiki/Extremophile

Andy

Well, that's slightly different - the extremophiles tend to live in
environments which are hostile to most known life, but I would doubt
that there are any bugs capable of breeding through cell lysis! Could
be wrong though, and if I am, it'll be brilliantly interesting to read
up about them.

On 29/05/2011 23:07, David Paste wrote:

Well, that's slightly different - the extremophiles tend to live in
environments which are hostile to most known life, but I would doubt
that there are any bugs capable of breeding through cell lysis! Could
be wrong though, and if I am, it'll be brilliantly interesting to read
up about them.

Well, I'm censored large number years out of date but...

I guess the effect of this stuff is to punch holes in the cell
membranes. Enough holes, no cell. So if there's enough to punch a few
holes, but not actually kill it, and there's some variation in the
ability of the bugs to fix the holes, why would you not have selection
for something able to survive in a weak concentration? And then they
can gradually work their way up the drain to the source of the poison
where the concentrations are higher and nothing else can survive.

After all that's the way antibiotic resistance has been bred.

Andy

On May 30, 2:14*pm, Andy Champ wrote:

Well, I'm censored large number years out of date but...

I guess the effect of this stuff is to punch holes in the cell
membranes. *Enough holes, no cell. *So if there's enough to punch a few
holes, but not actually kill it, and there's some variation in the
ability of the bugs to fix the holes, why would you not have selection
for something able to survive in a weak concentration? *And then they
can gradually work their way up the drain to the source of the poison
where the concentrations are higher and nothing else can survive.

After all that's the way antibiotic resistance has been bred.

Andy

I think penicillin acts in a different manner to stuff like bleach and
p/acid. But I still remain open to the possibility of a resistance to
it, I am not an expert, and am happy to accept the evidence.

On 30/05/2011 19:28, Tim Streater wrote:

Antibiotics work by getting into the bacterial cell and interfering with
some chemical process within it - e.g. inhibiting the production of some
vital enzyme. Bleach and strong acids physically destroy the bacteria.

It's a bit akin to: cyanide will poison us by interfering with our
metabolism. A bullet does it by destroying some vital organ.


IIRC Penicillin interferes with cell wall construction, and prevents
growth. Ah...

http://en.wikipedia.org/wiki/Penicil...nism_of_action

But why wouldn't we be able to evolve resistance to bullets? Toss
enough airgun pellets about, and we'll likely evolve thicker skins (or
faster reactions!) just the way we evolved sickle cell anaemia (gives
malaria resistance) and cystic fibrosis (Cholera).

And in time we'll become .22 resistant... DU cannon shells might take a
while though.

Bacteria of course do all this _much_ faster.

Andy

On Tue, 31 May 2011 20:19:08 +0100, Andy Champ
wrote:

On 30/05/2011 19:28, Tim Streater wrote:

Antibiotics work by getting into the bacterial cell and interfering with
some chemical process within it - e.g. inhibiting the production of some
vital enzyme. Bleach and strong acids physically destroy the bacteria.

It's a bit akin to: cyanide will poison us by interfering with our
metabolism. A bullet does it by destroying some vital organ.


IIRC Penicillin interferes with cell wall construction, and prevents
growth. Ah...

http://en.wikipedia.org/wiki/Penicil...nism_of_action

But why wouldn't we be able to evolve resistance to bullets? Toss
enough airgun pellets about, and we'll likely evolve thicker skins (or
faster reactions!) just the way we evolved sickle cell anaemia (gives
malaria resistance) and cystic fibrosis (Cholera).

And in time we'll become .22 resistant... DU cannon shells might take a
while though.

Where was I hearing all about this, the other day? If it wasn't
'Thinking Allowed' it might have been 'The News Quiz' where generation
after generation of mice have had their tails cut off in the (vain)
hope that it might lead to a specis of tail-less mice. Twas commented
that it was all a waste of mice (and tails) since at least one subset
of the human race has been chopping bits off male babies' bodies for
some 1,200 generations with no sign of it evolving into a natural
feature.

Nick

On May 31, 8:19*pm, Andy Champ wrote:

IIRC Penicillin interferes with cell wall construction, and prevents
growth. *Ah...

http://en.wikipedia.org/wiki/Penicil...nism_of_action

But why wouldn't we be able to evolve resistance to bullets? *Toss
enough airgun pellets about, and we'll likely evolve thicker skins (or
faster reactions!) just the way we evolved sickle cell anaemia (gives
malaria resistance) and cystic fibrosis (Cholera).

And in time we'll become .22 resistant... DU cannon shells might take a
while though.

Bacteria of course do all this _much_ faster.

Andy

I'd have to remain sceptical of this idea! But it's an entertaining
thought!

In message , Nick Odell
writes
On Tue, 31 May 2011 20:19:08 +0100, Andy Champ
wrote:

On 30/05/2011 19:28, Tim Streater wrote:

Antibiotics work by getting into the bacterial cell and interfering with
some chemical process within it - e.g. inhibiting the production of some
vital enzyme. Bleach and strong acids physically destroy the bacteria.

It's a bit akin to: cyanide will poison us by interfering with our
metabolism. A bullet does it by destroying some vital organ.


IIRC Penicillin interferes with cell wall construction, and prevents
growth. Ah...

http://en.wikipedia.org/wiki/Penicil...nism_of_action

But why wouldn't we be able to evolve resistance to bullets? Toss
enough airgun pellets about, and we'll likely evolve thicker skins (or
faster reactions!) just the way we evolved sickle cell anaemia (gives
malaria resistance) and cystic fibrosis (Cholera).

And in time we'll become .22 resistant... DU cannon shells might take a
while though.

Where was I hearing all about this, the other day? If it wasn't
'Thinking Allowed' it might have been 'The News Quiz' where generation
after generation of mice have had their tails cut off in the (vain)
hope that it might lead to a specis of tail-less mice. Twas commented
that it was all a waste of mice (and tails) since at least one subset
of the human race has been chopping bits off male babies' bodies for
some 1,200 generations with no sign of it evolving into a natural
feature.

Nick

but that is arse about face, you will only evolve a tai less mouse or
whatever if there is some selection pressure - some benefit, to being
naturally taiiess, and so selecting those genes. Whatt you are
selecting for though is mice that are good at surviving and breeding
with their tais cut off.

The way to do it is to allow only those mice with short tails to breed
--
Chris French

"David Paste" wrote in message
...
On May 31, 8:19 pm, Andy Champ wrote:

IIRC Penicillin interferes with cell wall construction, and prevents
growth. Ah...

http://en.wikipedia.org/wiki/Penicil...nism_of_action

But why wouldn't we be able to evolve resistance to bullets? Toss
enough airgun pellets about, and we'll likely evolve thicker skins (or
faster reactions!) just the way we evolved sickle cell anaemia (gives
malaria resistance) and cystic fibrosis (Cholera).

And in time we'll become .22 resistant... DU cannon shells might take a
while though.

Bacteria of course do all this _much_ faster.

Andy

I'd have to remain sceptical of this idea! But it's an entertaining
thought!

It would be far more efficient to measure skin thickness and sterilise those
with thin skin.

Likewise we could extend human life by sterilising the off spring of those
that don't live a long time.
Its too late to do anything after the breeding period has passed so you have
to tackle the off spring.

On Jun 1, 1:21*pm, "dennis@home" wrote:

Likewise we could extend human life by sterilising the off spring of those
that don't live a long time.

That wouldn't extend human life, it'd shift the mean, but then you've
got to take regression to mean into account - maybe the long-lived
ones were an anomaly? Anyway, what with all this climate change, we
should be encouraging people to breed less and live shorter lives!

(I am not a eugenicist)

On 01/06/2011 16:45, David Paste wrote:
On Jun 1, 1:21 pm, wrote:

Likewise we could extend human life by sterilising the off spring of those
that don't live a long time.

That wouldn't extend human life, it'd shift the mean, but then you've
got to take regression to mean into account - maybe the long-lived
ones were an anomaly?

Not necessarily - what you say would be right if human lifetime was
random, but it isn't - some people are more susceptible to eg heart
disease or cancer, so removing the people who die earlier would put a
selective bias towards the longer lived.

(at the moment there's little selective bias - most people live long
enough to breed, and that's what counts - the extra years afterwards
don't help much)