NEW PRODUCT ANNOUNCEMENT March 2002

From Jan R. van der Ploeg at the University of Zurich comes a set of four strains, each containing a knockout in one or more sulfur source utilization genes. Many laboratory media supply inorganic sulfur in the form of sulfate salts. In the soil habitats of a typical Bacillus species, however, the most commonly available sulfur source is likely to come in the form of sulfonate (1). The ssuABC genes, located at about 82° on the B. subtilis 168 chromosome, encode an ATP-dependent transport system for alkanesulfonates (3). The ssuD gene, located in the same operon, encodes a monooxygenase required for the desulfonation of these compounds. The cysIJ genes encode sulfite reductase, which catalyzes the reduction of sulfite to sulfide, a required step in the utilization of both sulfates and sulfites in B. subtilis (2). Finally, the cysK gene product, cysteine synthase, catalyzes the formation of cysteine from sulfate. B. subtilis apparently makes a second cysteine synthase as well, but a cysK mutant still grows slowly on inorganic sulfur (2).

Below are descriptions of each of these new strains. We thank Dr. van der Ploeg for making them available to the BGSC.

BGSC	Original	Genotype	Phenotype	Ref
1A800	SB10	trpC2 thr-5 his ΔssuAC::kan	Unable to utilize primary aliphatic sulfonates as a source of sulfur, most likely due to disruption of uptake system. The ssuA and ssuC genes are also known as ygbA and ygaM, respectively.	3
1A801	SB11	trpC2 cysK::Tn10 Sp	Reduced growth rate on sulfate, butanesulfonate, and sulfite as sulfur source	2
1A802	SB12	trpC2 cysIJ::kan	Deficient in sulfite reductase; unable to utilize sulfate, sulfite or butanesulfonate as a source of sulfur. The cysIJ genes are also known as yvgRQ.	2
1A803	MS11-6	hisA1 trpC2 thr-5 ssuD::lacZ (Tn917-lac) cysK::Tn10 Sp	Reduced growth rate on sulfate, butanesulfonate, and sulfite as sulfur source	2

1. Autry, A. R., and J. W. Fitzgerald. 1990. Sulfonate S: a major form of forest soil organic sulfur. Biol Fertil Soils 10:50-56.

2. van der Ploeg, J. R., M. Barone, and T. Leisinger. 2001. Functional analysis of the Bacillus subtilis cysK and cysJI genes. FEMS Microbiology Letters 201:29-35.

3. van der Ploeg, J. R., N. J. Cummings, T. Leisinger, and I. F. Connerton. 1998. Bacillus subtilis genes for the utilization of sulfur from aliphatic sulfonates. Microbiology 144:2555–2561.