Culture Collections


The glossary is an alphabetical list of acronyms and terms related to our products.

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  • Passage

    The transfer or transplantation of cells, with or without dilution, from one culture vessel to another. It is understood that any time cells are transferred from one vessel to another, a certain portion of the cells may be lost and therefore, dilution of cells, whether deliberate or not, may occur. This term is synonymous with the term 'subculture'.

  • Passage Number

    The number of times the cells in the culture have been subcultured or passed. In descriptions of this process, the ratio or dilution of the cells should be stated so that the relative cultural age gap can be ascertained. This term is not synonymous with population doubling.

  • PBS

    Phosphate Buffered Saline(calcium and magnesium free)

  • PBS

    Phosphate buffered saline

  • PCI

    Penicillin Control and Immunology Section, Food andDrug Administration, Washington DC, USA

  • PG

    Collection of Mycoplasmas of Dr D G ff Edwards, formerly at Burroughs Wellcome Research Laboratories, Beckenham, Kent UK

  • PHA


  • Phenotype

    The expressed characteristics of a cell or cell culture. This includes the morphology, markers, products secreted and all other physical attributes.

  • PHLS

    Public Health Laboratory Service, England and Wales , now subsumed within the Health Protection Agency

  • Ploidy

    A description of the number of chromosome sets included in a cell. eg. 2n - diploid/normal cells, 3n - triploid, 4n - tetraploid, etc.

  • PMA

    Phorbol Myristate Acetate

  • Population Doubling Level

    The total number of population doublings of a cell line or strain since its initiation in vitro . A formula to use for the calculation of 'population doublings' in a single passage is: number of population doublings = Log10(N/N0) X 3.33 where: N= number of cells in the growth vessel at the end of a period of growth N0= numberof cells plated in the growth vessel. It is best to use the number of viable cells or number of attached cells for this determination. Population doublings level is synonymous with 'cell generation time'.

  • PPE

    Personal Protective Equipment

  • Price Code

    The way in which ECACC prioritises its cell line stocks. Price code A reflects those cell lines ordered most often and so the banks are larger and more cryogenic storage space is assigned to them. Other price codes consist of cell lines that are ordered less often and so stocks are smaller and more labour intensive.

  • Primary Culture

    A culture started from cells, tissues or organs taken directly from organisms. A primary culture may be regarded as such until it is successfully subcultured for the first time,  when it becomes a 'cell line'.

  • Pro-cck


  • Proliferation

    Refers to an increase in viable cell numbers in a population or when a single cell doubles.

  • PS

    Propagating strain for staphylococcal bacteriophages

  • Pseudodiploid

    This describes the condition where the number of chromosomes in a cell is diploid but, as a result of chromosomal rearrangements, the karyotype is abnormal and linkage relationships may be disrupted.

Disclaimer: We make every effort to ensure that this information is accurate and up-to-date. We accept no responsibility for errors and omissions.

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