Accumulation of ppGpp and ppGp in Staphylococcus aureus 8325-4 following nutrient starvation.
OBJECTIVE
To investigate the accumulation of highly phosphorylated guanosine nucleotides in Staphylococcus aureus 8325-4 following nutrient deprivation.


RESULTS
Nutrient shiftdown of Staph. aureus, HPLC of nucleotides and Western blotting of cell-free extracts. ppGpp rapidly accumulated when cells were deprived of isoleucine following addition of mupirocin, or after carbon deprivation. In contrast, total amino acid starvation led to delayed production of ppGp, which suggests that Staph. aureus exhibits a unique response to total amino acid deprivation compared with other eubacteria. Intracellular ppGp was observed at high levels under all starvation conditions, which suggests that this nucleotide is linked to nutrient limitation and may therefore be involved in regulating the stringent response in Staph. aureus. pppGpp was not observed under any nutrient-limiting condition. Western blot analysis of whole-cell extracts from Staph. aureus 8325-4, showed that antibodies to RelA and SpoT cross-reacted under conditions that detected these proteins in Escherichia coli.


CONCLUSIONS
Staph. aureus produces ppGpp and ppGp following nutrient limitation. Immunological analysis indicates that Staph. aureus contains RelA and SpoT proteins, similar to those produced by E. coli.


CONCLUSIONS
This study provides a new example of the diversity of metabolic regulations in bacteria.
Crosse
A M
AM
Department of Biological Sciences, University of Central Lancashire, Preston, UK.
Greenway
D L
DL
England
R R
RR
D000596:Amino Acids / Q000378:metabolism*; D015153:Blotting, Western; D002244:Carbon / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D006150:Guanine Nucleotides / Q000378:metabolism*; D006159:Guanosine Tetraphosphate / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000235:genetics / Q000378:metabolism*
D000596:Amino Acids; D003470:Culture Media; D006150:Guanine Nucleotides; D006159:Guanosine Tetraphosphate; C018957:guanosine 5'-diphosphate-3'-monophosphate; D002244:Carbon