What does the ampoule pellet consist of?
A freshly cultivated cell suspension of the microorganism is either dropped onto a pre-dried protectant/carrier or the culture suspension is mixed with a liquid protectant/carrier. Depending on the strain, different protectants/carriers are used leading to the different appearance of some of the pellets. In most cases, the protectant/carrier is the main component of the pellet. Therefore, when initially re-activating the strain the whole of the pellet must be resuspended and transferred into a small volume of medium (5-10 mL) so that the number of cells is sufficient for subcultivation.
Why do some ampoules contain blue, others red indicator?
“Silica Gel Orange” replaces silica gel (with a blue indicator) in order to minimise the use of hazardous chemicals. Both indicators change colour in the presence of humidity (indicating damaged ampoules): blue to pink, red to orange. Ampoules with blue or red indicator have an intact vacuum. Please check the colour of the indicator before opening the ampoule.
How many cells does an ampoule contain?
The cell numbers present in a pellet differ due to strain-specific preservation conditions. Each lot is routinely checked for strain viability so that the DSMZ guarantees that a sufficient number of cells are present to allow successful reactivation and subcultivation.
If no liquid medium is recommended in the specific strain entry, which solution do I use to solubilize the freeze-dried pellet (reactivation) or to cultivate the strains in liquid medium?
Generally, use the recommended medium without the addition of agar. For fastidious microorganisms which grow only on solid media (e.g. M 693; M 429; M 585) use complex liquid media like M 1; M 545 or M 92. Please keep in mind: it is better to use any peptone or casamino acid or yeast extract containing medium than water or buffer for the solubilization of the pellet.
Why do some ampoules contain a black pellet?
Several strains of fastidious microorganisms, especially strictly anaerobic bacteria, are suspended prior to lyophilization in a protectant mixture containing ferrous sulfide or charcoal, which gives the pellet a black colour.
How to reactivate fastidious bacteria from ampoules?
For many fastidious organisms a higher inoculum is needed to reactivate them. Add 0.5 ml of adequate liquid medium (given for each strain in its specific strain entry) to the pellet and dissolve the pellet as quickly as possible, then dilute the suspension with 4.5 ml of the same medium. For strains that grow only on plates but not in liquid media, distribute at least 1 ml suspension on each agar plate. If the strain does grow also in liquid medium use 1 ml for inoculation of 5 ml liquid medium, plate the rest on agar plates also using 1 ml suspension per plate. In some cases it is recommended to resuspend the material of one ampoule in 1 ml and plate it completely onto one single agar plate. This is then mentioned in the specific strain entry.