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Re: Killie Fry and velvet



On 1 Jul 2001, at 9:00, Mach Fukada wrote:

> Hi Bill,
>     That sounds more like a bacterial infection than velvet if it was
> inhibited by peat.  

Got to agree here Mach, Bill it sounds more like a 
bacteria than a velvet infection.

> I recall many bacteria are inhibited by acidic (lower
> pH) situations. 

That is one possibilty... Various moss species produce 
antibitoic compounds (moss, growing in nutrient poor 
situations don't like compettion). If the peat was of 
the fibrous mossy stuff then that could explain the 
"cure". 
The "Greenmoss" that was mentioned some months back 
appears to have these properties.

> Supposedly this is why there are problems with canning
> non-acidic foods as the anaerobic, non-acidic conditions are ideal for
> botulism.  I suspect that there are other bacteria that are inhibited by
> acidic conditions.  

The acidity issue has it routes in the manner how the 
bacteria generate their ATP. They set up proton 
gradients accross their cell walls. The higher the 
proton (H+) concentration already outside their cell 
wall the more difficult it becomes to maintain the 
gradient used to generate ATP. Eventually the proton 
concentrations equilibriate between the medium and 
cytoplasm and that is when the bacteria's ticket gets 
punched... This type of inhibition is just as effective 
under aerobic and anaerobic conditions.
Under anaerobic conditions bacteria can still live by 
means of glycolysis (metabolism of glucose to pyruvate + 
2H+). Increased proton concentration (a low pH) puts 
pressure on the metabolism, slowing the rate of 
glycolysis and making the bacteria very unhappy.

As a side note, some canned good are now being 
innoculated with bacteria of the genus Leuconostoc (if I 
recall correctly). These bacteria produce antimicrobial 
peptides that rip the cells walls of other bacter apart 
or punch holes through them and disrupting the ion 
gradients the bacteria use to generate their ATP and 
other "energy" carriers.

>     BTW: the fish you sent to me  are doing great.  The zygamia are starting
> to spawn, not nearly as prolific as the occelatum..

We had occelatum here once upon a time... Also bred like 
rabbits but when summer came... Well, we don't have 
occelatum any more.
Watch out for the heat Mach. It only took 1 week at 27oC 
to do these guys in.

Bye

Tyrone Genade
Southern African Killifish Society Coastal & Offshore Coordinator
AKA 08248
tyronegenade at yahoo_com
http://www.geocities.com/tyronegenade

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P450 Lab, Biochemistry Department
University of Stellenbosch, 7602, South Africa
Ph: +27-021-808-5876, fax: +27-021-808-5863
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