Identification of two proline transport systems in Staphylococcus aureus andtheir possible roles in osmoregulation

Article Abstract:

Staphylococcus aureus produces enterotoxins within various foods. This enterotoxin-producing ability is favored by several conditions such as low-water activity. Osmotic stimulation of this bacterium makes it fairly adaptable to low-water activity environments. This study shows the presence of two proline transport systems within the whole cells of Staphylococcus aureus to which its osmotolerance is attributed. One of the transport system, the low-affinity transport system, seems to be the primary system responsible for the uptake of proline. This system is triggered by sodium chloride concentrations and exposure to high concentrations of non-permeating solutes, both ionic and non-ionic.The osmoregulatory properties of this microorganism may be explained more by futurestudies following identification of the transport systems in this study.

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Identification of a high-affinity glycine betaine transport system in Staphylococcus aureus

Article Abstract:

A high-affinity betaine transport system was recorded in the Staphylococcus aureus, and it was seen that this bacterium accumulates proline and glycine betaine when cells are grown at low water activity. Optimal activity for this transport system was measured in the presence of high NaCl concentrations, although transport activity was not stimulated by high concentrations of other solutes. Standard assay conditions were used and cells suspended in transport buffer at a concentration of 150 micrograms of total cellular protein per milliliter and the rate of glycine betaine uptake was expressed as nanomoles per minute per milligram of total cellular protein.

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Identification of a PutP proline permease gene homolog from Staphylococcus aureus by expression cloning of the high-affinity proline transport system in Escherichia coli

Article Abstract:

An existing strategy helps identify the structural gene encoding the high-affinity proline permease of Staphylococcus aureus. Functional expression in an Escherichia coli host helps clone the gene. Sequence analysis reveals the presence of a protein of 497 amino acids in the Staphylococcus proline permease gene and the protein exhibits 49% homology with the PutP high-affinity proline permease of E. coli.

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