Spatial constraints within the chlamydial host cell inclusion predict interrupted development and persistence

BMC Microbiology

Table 1 Parameter definitions and ranges used in our biomathematical simulations

Parameter	Definition	Range	References
t _d	Average doubling time of RBs during phase of exponential growth (replication and division of bodies)	1.5–2.6 hrs	[1-3]
α ₀	Proportion of total doubling time in which RB genomes are dividing into separate bodies during uninhibited exponential growth	0.1–0.5
1/k	Average time for RB detachment from the inclusion membrane and migration to the lumen to occur, when the number of injectisomes is half the threshold level	0.01–1.0 hrs	†
1/μ	Average time for RB-EB differentiation	1–4 hrs	[2, 3, 38]
L	Average center-to-center spacing between T3S needles on the RB surface	40–50 nm	[10, 32]
l _p	Average length of each needle	5–10 nm	§ [33]
r	Radius of each RB (without stress)	0.5–0.6 μm	[38]
r _E	Radius of each EB	0.1–0.2 μm	[38]
Cell_vol	Volume of host cell	1700–2500 μm³	Experimental Variable
ε	Proportion of cell space occupied by cell nucleus, mitochondria, etc.	0.2–0.4	Experimental Variable
V _I	Volume within the lumen occupied per detached RB (considering effects of steric hindrance)	V_I= (2r)³
V _E	Volume within the lumen occupied per EB (considering effects of steric hindrance)	V_E= (2r_E)³
P _lim	Threshold number of injectisomes per RB for the detachment of RBs from the inclusion membrane	21–25	[9]

†: Experimental variable. It was calibrated so that it matched observational experimental time courses.
§: The full length of the needle has been measured to be 10–25 nm, but we assume that the length of the needle between the RB and the CIM required to establish effective contact is 5–10 nm.

ISSN: 1471-2180