Cultivation and storage
Storage
Luminescent
bacteria can be stored as standard glycerol stab cultures.
This is the method of preparing glycerol stab cultures of
bacteria:
- In the sterile
plastic tube mix 0,15 ml sterilised glycerol and 0,85 ml
liquid culture of luminescent bacteria
- Shake the mixture
well
- The mixture should
be frozen immediately using liquid nitrogen
- Store the cultures
in the temperature of -70°C
Cultivation of
Luminescent Bacteria
Cultivation of
luminous bacteria is processed on the special medium "BOSS"
This is the method of preparation the medium "BOSS":
| |
 |
30
g |
NaCl |
| |
|
1 g |
Glycerol |
| |
|
10
g |
Peptone (Bacto-Peptone) |
| |
|
3 g |
Beef Extract |
| |
|
(to obtain
solid medium you should add 15 g of Bacto-Agar) |
| |
|
Dilute the
ingredients in water (pH should be about 7,3) |
| |
|
Fill with H2O
up till 1000 ml |
There are some
additional microbiological media used for cultivation of
luminescent bacteria:
The cultivation
should be conducted in temperature 18 - 22°C. Liquid cultures
should be well aerated (the aeration pumps may be used or
cultures should be shaken well). It is necessary to support
sufficient amount of oxygen needed in luminescence reactions.
The
photos above show liquid culture of luminescent bacterium - Photobacterium
luciferum.
When
we observe the culture of luminous bacteria in well lit place the
light emitted by bacteria is not visible (photo 1). If we observe
the same culture in the darkness the intensity of glowing is
unbelievable (photo 2). Some of my friends connect this green
light with UFOs. 
It
is interesting to point out that in order to take the photos (particularly
photo 2) I had to support constant movement of the broth. If the
culture was not mixed the intensity of growing was dropping
drastically in some seconds - probably it was caused by lack of
oxygen. I solved the problem by using magnetic stirrer.
(click on
the photo to see it better)
On solid medium the
most intensive glowing can be observed 1 - 5 days after
inoculation but faint glowing can be observed longer (even some
weeks). Big differences between different species of luminescent
bacteria can be observed here (from my observation it occured
that the shortest time of glowing have the luminescent bacterium
- Vibrio harveyi).
Both
pictures show the same culture of luminescent bacterium - Vibrio
fischeri on the petri plates with medium "BOSS".
Photo 1 was taken with regular light whereas photo 2 I took in
darkness giving it long time of exposure.
(click on
the photo to see it better)
The above photos show cultures of luminescent bacterium - Photobacterium
phosphoreum on petri plates with medium "BOSS".
The cultures was started soon before Christmas'97. As you can see
we can obtain interesting effects streaking bacteria in such a
way that after incubation we obtain glowing pictures.
