Cell count and normalization in HRR

high-resolution terminology - matching measurements at high-resolution

Cell count and normalization in HRR

Description

Cell count N_ce is the number of cells, expressed in the unit [x] (1 Mx = 10⁶ x). Normalization of respiratory rate by cell count yields oxygen flow I_O2 expressed in units [amol·s^-1·x^-1] (=10^-18 mol·s^-1·x^-1).

Abbreviation: N_ce

Reference: BEC 2020.1 doi10.26124bec2020-0001.v1, Gnaiger 2020 MitoPathways

Communicated by Gnaiger Erich 2020-09-18

Cell concentration from cell suspension to experimental chamber

Table 1. Definition of terms, symbols and units.

Term	Symbol	=	Definition	Unit	Comment
Volume of cell suspension σ	Vσ			mL	The symbol σ is used for 'suspension', distinguished from the symbol s for 'sample'. Frequently the sediment of cells obtained from centrifugation is re-suspended in the experimental medium (e.g. MiR05 plus pyruvate) to obtain Vσ.
Cell count in Vσ	Nce,σ	=	Cce,σ∙Vσ	mL	The total cell harvest available for respirometry and additional analyses of this sample of cells.
Cell-count concentration in cell suspension Vσ	Cce,σ	=	Nce,σ/Vσ	mL
Subsample from Vσ for cell counting	Vσ→N			mL	For reliable normalization of respiration, Vσ→N should be equal or larger than 0.05 mL. Smaller volumes are taken as a subsample for counting, if the aim is merely to define a procedure of dilutions, with final subsamples taken after dilutions for cell-counting.
Subsample from Vσ for respirometry J	Vσ→J	=	Vσ-Vσ→N	mL	.
Experimental chamber volume	V			mL	Effective aqueous volume in the experimental system (2.0 mL or 0.5 mL)
Experimental chamber volume + VStopper capillary	V'	=	V+VStopper capillary	mL	2.085 or 0.54 mL
Experimental chamber volume + VStopper capillary + subsample volume	V''	=	V'+Vsubsamples	mL	Subsamples taken from the O2k chamber prior to closing the chamber.
Cell-count in experimental chamber	Nce	=	N·Uce	x	106 x = 1 Mx
Cell-count concentration in experimental chamber	Cce	=	Nce/V	Mx/mL	106 x/mL = 1 Mx/mL = 109 x/L = 1 Gx/L
Volume of respirometric stock J	VJ	=	Vs→J + ΔVJ	mL

MitoPedia methods: Respirometry 

MitoPedia O2k and high-resolution respirometry: DatLab, O2k-Respirometry, O2k-FluoRespirometry