ISO 19040-2:2018 水質 — 水と廃水のエストロゲンポテンシャルの決定 — Part 2: 酵母エストロゲンスクリーニング（A-YES、Arxula adeninivorans） | ページ 5

3.1

blank replicate

additional replicate that contains no test organism, but is treated in the same way as the other replicates of a sample

[SOURCE:ISO 10872:2010, 3.5]

3.2

culture medium

nutrients presented in a form and phase (liquid or solidified) which support microbiological growth

3.3

dilution level

D

denominator of the dilution coefficient (using the numerator 1) of a mixture of water or waste water with dilution water as integral number

Note 1 to entry: For undiluted water or waste water, this coefficient per definition is 1→1. The corresponding and smallest possible value of D is 1. In this document, the arrow indicates the transition from initial total volume to final total volume.

[SOURCE:ISO 6107‑6:2004, 28]

3.4

dilution water

water added to the test sample to prepare a series of defined dilutions

[SOURCE:ISO 20079:2005, 3.7]

3.5

50 % effect concentration

EC₅₀

concentration of a compound which causes 50 % of an effect

Note 1 to entry: In the sense of this document the EC₅₀ is the concentration of a compound which induces 50 % of the maximal reporter gene activity which can be achieved by this compound.

3.6

field blank

container prepared in the laboratory, using reagent water or other blank matrix, and sent with the sampling personnel for exposure to the sampling environment to verify possible contamination during sampling

[SOURCE:ISO 11074:2015, 4.5.3]

3.7

growth rate

proportional rate of increase in cell density

[SOURCE:ISO 10253:2006, 3.2]

3.8

induction rate

quotient of the mean value of wells with enhanced reporter gene activity measured on the plates treated with a dose of the test sample, and the mean value of the corresponding wells treated with the negative control using the same strain under identical conditions

Note 1 to entry: Instead of the negative control, the estimated parameter A of the four-parameter model, which describes the dose response relationship between reference compound and the induction rate, can be used.

[SOURCE:ISO 6107‑6:2004, 43, modified —"wells with enhanced reporter gene activity measured" replaces"mutant colonies";"corresponding wells" replaces"corresponding plates"; “quotient” replaces “difference”.]

3.9

inoculum

fraction of a culture of microorganisms used to start a new culture, or an exponentially growing preculture, in fresh medium

[SOURCE:ISO 6107‑6:2004, 44]

3.10

lowest ineffective dilution value

LID

lowest dilution within a test batch which does not show any effect, i.e. no statistically significant increase in the reporter gene activity compared with the negative control

[SOURCE:ISO 11350:2012, 3.4, modified — “increase in the reporter gene activity” replaces “increase in the number of revertant wells”.]

3.11

negative control

dilution water without test sample

[SOURCE:ISO 6107‑6:2004, 51]

3.12

reference compound

compound with one or more property values that are sufficiently reproducible and well established to enable the calibration of the measurement method

[SOURCE:ISO 7405:2008, 3.6, modified — “compound” replaces “material”; “the calibration of the measurement method” replaces “use of the material or substance for the calibration of an apparatus, the assessment of a measurement method or for the assignment of values to materials”.]

3.13

reporter gene activity

quantitative activity of a gene attached to the promoter sequence of another gene

3.14

test sample

undiluted, diluted or otherwise prepared portion of a sample to be tested, after completion of all preparation steps such as centrifugation, filtration, homogenization, pH adjustment and determination of ionic strength

[SOURCE:ISO 6107‑6:2004, 92]