Table II.

Comparison of the Effect of the Glutamine Synthetase Inhibitor l-Methionine-S-Sulfoximine and Two Standard Antibiotics on the M. tuberculosis Cell Wall Components Poly-l-Glutamate/Glutamine and Peptidoglycan

		l-Methionine-S-Sulfoximine										Amikacin						Rifampin
						μM								μg/ml						μg/ml
Inhibitor/antibiotic concentration		0		0.2		2		20		200		0.06		0.25		1		0.0125		0.05		0.2
Poly-l-Glutamate/glutamine (μg/1010 Cells)		46		18.2		9.8		6.1		3.2		49.9		43.2		26.0a		54.2		41.6		40.0a
d,l-Alanine (μg/1010 Cells)		21		21.2		17.7		17.8		16.6		29.1		26.3		12.0a		23.6		25.1		20.0a

^aAt high concentrations, amikacin (1 μg/ml) and rifampin (0.2 μg/ml) were lytic for M. tuberculosis. Consequently, the values shown for poly- l-glutamate/glutamine and d,l-alanine at these concentrations of antibiotic are calculated on the basis of <1–5 × 10⁷ cells for 1 μg/ml amikacin and 10⁷ cells for 0.2 μg/ml rifampin. The SD for all presented values was ≤15%.