Sulphur acquisition in Neisseria meningitidis

Neisseria meningitidis is able to utilize a variety of biologically relevant compounds as its sole source of sulphur. Sulphate transport in the meningococcus is temperature-, pH-, concentration-, and energy-dependent. Group VI anions and sulphur-containing amino acids affect sulphate uptake. Selenate is a competitive inhibitor of sulphate transport and enters the meningococcus via the sulphate transporter. L-cysteine, a noncompetitive inhibitor of sulphate transport, exerts allosteric control on the system. L-cysteine has its own energy-dependent uptake system. Thiocyanate, a unique sulphur source for a heterotrophic bacterium, appears to be transported in the meningococcus by a system other than that for sulphate or L-cysteine uptake. Sulphur starvation enhances transport capacity and causes variations in some of the enzymes in the meningococcus. The sulphur source used for growth causes changes in the protein profiles of the envelope and cytosol fractions. The soluble sulphur pool in N. meningitidis regulates transport and metabolism of sulphur-containing compounds. The presence of thiosulphate reductase may be to allow thiosulphate to serve as an alternate electron acceptor during in vivo anaerobic growth