TABLE 1.

Characterization of M. smegmatis ndh mutants

Strain	ndh allele	Mutation		MIC (μg/ml)			% Viability at 42°Ca
		DNA	Amino acid	INH	ETH	TRC
mc2155	ndh	Wild type	Wild type	5	10	10	100
mc22374	ndh-64	T50C	I17T	>100	>100	25	55
mc22375	ndh-52	A85C	T29P	>100	50	10	31
mc22376	ndh-101	A137C	H46P	>100	>100	25	99
mc22377g	ndh-61	G251A	G84D	>100	>100	25	1
mc22378	ndh-11	T299C	L100P	100	>100	10	1
mc22379	ndh-16	G343Ab	A115T	>100	>100	25	10
mc22380	ndh-13	T364A	Y122N	>100	>100	25	10
mc22381	ndh-32	C433Tc	R145C	>100	>100	25	1
mc22382	ndh-41	T509C	F170S	>100	>100	10	45
mc22383	ndh-23	G559Cd	A187P	50	50	25	12
mc22384	ndh-71	T737C	V246A	>100	>100	10	30
mc22385	ndh-17	T815A	V272E	>100	>100	10	46
mc22386	ndh-22	T899Ge	V300G	>100	>100	25	30
mc22387	ndh-31	G1005T	Q335H	100	100	10	35
mc22388	ndh-84	T1081Cf	Y361H	>100	100	10	50

^aViability at 42°C was defined as the percentage of cells that survived incubation at 42°C. Ten- fold serial dilutions of mycobacterial cultures were plated at the nonpermissive temperature (42°C). After incubation at 42°C for 4 days, the plates were incubated at the permissive temperature (30°C) for 6 days. The number of CFU per milliliter obtained after the temperature shift was divided by the titer of the culture to give the percent viability at 42°C.

^bAlso found in mutant ndh-18. This was the only mutation previously isolated (36).

^cAlso found in mutants ndh-63 and ndh-93.

^dAlso found in mutant ndh-12.

^eAlso found in mutants ndh-24, ndh-51, and ndh-83.

^fAlso found in mutants ndh-62, ndh-81, ndh-82, and ndh-85.

^gThe M. smegmatis ndh Ts lethal mutants are shown in bold.