Guidelines
CELL LINES
PLANT CELL LINES
PLANT VIRUSES
PLASMIDS
PHAGES
MICROORGANISMS
GENOMIC LIBRARIES
PROCEDURES
CATALOGUE
LABORATORY PROCEDURES FOR PHAGES
REFERENCE NO: PH/2003/03/02
TITLE: QUALITY CONTROL CHECK
INTRODUCTION
This document describes the basic procedure to be followed when producing the master stock and the distribution stock for the public collection.
Definitions
- Master stock: The fully quality controlled stock of aliquots containing the original phage material. These aliquots are not used for distribution. They are only subcultured in case the quality control of the distribution stock fails and/or a new distribution stock has to be produced.
- Distribution stock: The fully quality controlled stock of phage aliquots, which are used for distribution.
- pfu = plaque forming units, parameter for determination of phage viability/infectivity
PROCEDURE
When the titre is acceptable (phage-dependent) and purity assessed, the stock is divided into aliquots for storage in liquid nitrogen (using glycerol) and a suspension for storage at either a different location or at a different temperature or using a different cryoprotectant. Titre and plaque morphology should be controlled regularly. High titre suspensions have 109 pfu/mL and more.
DSMZ normally stores 10 - 20 aliquots in NUNC ampoules in LN and these are sent out upon request. In cases where phages store well in the fridge, aliquots are kept there for sending out upon request. When running out of these distribution aliquots, there is production of a new series, a new distribution stock while going back to the most original stock as starting material. Each new distribution stocks receives a new series number. The new series (distribution stock) gets the complete QC procedure including photo documentation of plaques and titre control before defining it as the new distribution stock.
Guidelines
prepared for CABRI by DSMZ in cooperation with NCCB and NCIMB
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