TABLE 5.

DNA recovery and qPCR with different DNA extractions from heat-killed E. coli with or without transmembrane proteins exposed to the Pd or Pt compound^a

DNA extraction using glass beads (pellet + supernatant)	Treatment for LD discrimination	E. coli boiled in sterile water (1.8 × 109 cells/ml)			E. coli boiled in 1% Brij58 (1.8 × 109 cells/ml)b
		OD260/OD280	DNA concn (ng/μl)	CT by qPCR (cycle) (5 ng/qPCR)	OD260/OD280	DNA concn (ng/μl)	CT by qPCR (cycle) (5 ng/qPCR)
SAV/PPR/SDS + P/C/I	Pd (1,000 μM)	1.98 ± 0.03	127.0 ± 6.36	29.3 ± 0.37	1.98 ± 0.04	45.9 ± 4.76	39.5 ± 0.35
	Pt (1,000 μM)	1.85 ± 0.04	48.4 ± 3.87	38.6 ± 0.54	2.00 ± 0.03	27.0 ± 2.21	40.1 ± 0.51
	NT (no treatment)	1.96 ± 0.03	153.1 ± 9.72	20.5 ± 0.43	2.01 ± 0.03	91.7 ± 3.67	22.9 ± 0.38
SDS + P/C/I	Pd (1,000 μM)	1.77 ± 0.03	4.5 ± 0.42	38.3 ± 0.55	1.75 ± 0.01	2.8 ± 0.39	ND
	Pt (1,000 μM)	1.70 ± 0.04	3.9 ± 0.43	ND	1.93 ± 0.03	3.2 ± 0.33	ND
	NT (no treatment)	1.92 ± 0.03	118.1 ± 3.85	21.3 ± 0.62	1.99 ± 0.01	60.3 ± 2.14	22.1 ± 0.58
P/C/I alone	Pd (1,000 μM)	1.71 ± 0.03	2.9 ± 0.38	ND	1.67 ± 0.04	2.5 ± 0.34	ND
	Pt (1,000 μM)	1.64 ± 0.06	2.3 ± 0.32	ND	1.61 ± 0.03	2.3 ± 0.33	ND
	NT (no treatment)	1.91 ± 0.03	77.1 ± 3.43	23.2 ± 0.73	1.92 ± 0.01	30.2 ± 0.38	23.7 ± 0.66

^aGlass beads (pellet + supernatant): 10 mM Tris-HCl was added to all amounts of E. coli cells decomposed by glass beads, and their suspensions were supplied for DNA extraction. OD₂₆₀, optical density at 260 nm. OD₂₈₀, optical density at 280 nm. SAV/PPR/SDS: savinase, peptidase R, and SDS were added. P/C/I: DNA extraction by phenol, chloroform, and isoamyl alcohol. Pd: Cl₂(ŋ-cycloocta-1,5-diene)Pd(II). Pt: tetrakis(triphenylphosphine)platinum(0). ND, no qPCR elongation of the target gene.

^bBoiling in 1% Brij58 to remove membrane-spanning protein for E. coli cells was performed.