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Re: Aquatic Plants Digest V4 #239

>------------------------------
>James Purchase wrote:
>
>Interesting excerpt Paul.... given the fact that the majority of the
>bacteria which exist in an aquarium biofilter are species which seem to
>require high oxygen levels and relatively high nutrient levels, how likely
>is it that they have the same sorts of abilities as the subsurface bacteria
>described in the article? Just because some bacteria can do this, how
>general is the ability? Specifically, has anyone ever studied the abilities
>of the typical bacteria we see in an aquarium biofilter to adjust their
>metabolism/reproduction rate in response to periods of relatively low
>nutrient levels? Or is my thinking that they _require_ the high nutrient
>levels typically present in an aquarium incorrect?
>
>And how useful/capable would a bacterial colony which "held on" in a starved
>state for a protracted period of time be in a situation such as we see in
>our tanks? Would there still not be a relatively long time lag until the
>bacteria readjusted their metabolism and the population levels rebounded to
>"normal" levels (i.e measured in weeks, rather than hours or days)?
>

I would think that a lot of soil and water bacteria would have to exist on
quite low levels of food and/or energy sources most of the time.  Now and
then there are increases in nutrients, but for a lot of time, resources
would be quite low.  I know that we can keep bacterial cultures in tubes
for years without the bacteria dying out.  I use three or four common
species (Escherichia, Micrococcus, Bacillus) for a lab on bacteria every
year, and I have been innoculating broth cultures from the same agar slant
tubes for the last four years.  They are not multiplying visibly in the
slant tubes, but they recover and multiply __overnight__ in the broth
cultures.

Any decent college biology textbook will cover control of gene action in
bacteria.  Genes pertaining to a common function are grouped in sequences
called operons, which not only include the genes, but also DNA sequences
and regulator genes involved with turning the operon on or off.  One of the
best known operons is the lac operon that makes some enzymes necessary for
absorbing and digesting the sugar, lactose.  If lactose is absent, the
operon is turned off.  If it is present and glucose is absent, the operon
is turned on.  However, if lactose and glucose are both present, the lac
operon stays turned off.  Apparently, glucose is the preferred source of
energy, and is used preferentially to lactose.  Basically, if the gene
products of the operons aren't needed, the operons are turned off.  In
fact, it seems that almost all the operons can be turned off in a starving
bacterium.  They really can shut down to a minimum of energy expenditure
when food is low.  Bacteria have been on this earth for about 2.5 billion
years longer than us eukaryotic multicellular ogranisms, and they have had
plenty of time to evolve very sophisticated biochemical pathways.




 "Adam Novitt" <novitt at javanet_com> wrote:
>Subject: Mark Weiss Living Water
>
>As long as we are on the topic I was wondering what the thoughts are on Mark
>Weiss products, particularly Living Water Vital.  Does anyone know what this
>stuff is?  The labeling reads "DRAMATICALLY ENHANCES THE GROWTH OF AQUARIUM
>PLANTS WITHOUT NITRATES OR PHOSPHATES. BIOLOGICALLY DISCOURAGES ALGAE AND
>PARASITES WHILE ENHANCING BIOLOGICAL FILTRATION. INCREASES SPAWNING AND
>FERTILITY FOR YOUR COMMUNITY TANK CONTAINS NO NITRATES, PHOSPHATES OR
>SILICATES. NOT A TRACE ELEMENT, PLANT FOOD MEDICATION, FERTILIZER OR
>ALGICIDE."  Weiss products seem to have an air similar to that of ADA stuff,
>people seem to think that it is "good" but what is it?
>

I noticed that Mark Weiss also sells a product called Living Cactus Vital.
It purports to do similar wonderful things for cacti.

Paul Krombholz, getting some showers in Central Mississippi