The occurrence of cell-associated enterotoxin B in Staphylococcus aureus

1976 ◽  
Vol 22 (9) ◽  
pp. 1215-1221 ◽  
Author(s):  
Richard D. Miller ◽  
Daniel Y. C. Fung
Keyword(s):  
Staphylococcus Aureus ◽  
Stationary Phase ◽  
Cytoplasmic Membrane ◽  
Exponential Phase ◽  
Total Cell ◽  
Late Exponential Phase ◽  
Hypertonic Medium ◽  
Osmotic Lysis ◽  
Enterotoxin B

Cell-associated enterotoxin B was detected in lysates of cells of Staphylococcus aureus S-6 and 4916 disrupted by sonication or lysostaphin treatment. As much as 67% of this total cell-associated toxin was surface-bound, located outside the cytoplasmic membrane, and was released during protoplasting of this organism by lysostaphin treatment in hypertonic medium. The remainder of the cell-associated toxin was termed cytoplasmic and was released during osmotic lysis of the protoplasts. Levels of cell-associated toxin as a function of the age of the cells showed a rapid increase in both surface-bound, cytoplasmic, and total cell-associated toxin levels during the period of active toxin synthesis (late exponential phase of growth). These cell-associated toxin levels then reached a peak as the culture entered stationary phase, at a time corresponding to a decrease in the rate of toxin synthesis, and decreased slowly thereafter.

scholarly journals The Nature of Antibacterial Adaptive Immune Responses against Staphylococcus aureus Is Dependent on the Growth Phase and Extracellular Peptidoglycan

2019 ◽  
Vol 88 (1) ◽  
Author(s):  
Payal P. Balraadjsing ◽  
Lisbeth D. Lund ◽  
Yuri Souwer ◽  
Sebastian A. J. Zaat ◽  
Hanne Frøkiær ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
T Cell ◽  
Stationary Phase ◽  
Growth Phase ◽  
Cell Response ◽  
Th17 Cell ◽  
Exponential Phase ◽  
Th1 Cell ◽  
Content Type

ABSTRACT Staphylococcus aureus has evolved different strategies to evade the immune response, which play an important role in its pathogenesis. The bacteria express and shed various cell wall components and toxins during different stages of growth that may affect the protective T cell responses to extracellular and intracellular S. aureus. However, if and how the dendritic cell (DC)-mediated T cell response against S. aureus changes during growth of the bacterium remain elusive. In this study, we show that exponential-phase (EP) S. aureus bacteria were endocytosed very efficiently by human DCs, and these DCs strongly promoted production of the T cell polarizing factor interleukin-12 (IL-12). In contrast, stationary-phase (SP) S. aureus bacteria were endocytosed less efficiently by DCs, and these DCs produced small amounts of IL-12. The high level of IL-12 production induced by EP S. aureus led to the development of a T helper 1 (Th1) cell response, which was inhibited after neutralization of IL-12. Furthermore, preincubation with the staphylococcal cell wall component peptidoglycan (PGN), characteristically shed during the exponential growth phase, modulated the DC response to EP S. aureus. PGN preincubation appeared to inhibit IL-12p35 expression, leading to downregulation of IL-12 and an increase of IL-23 production by DCs, enhancing Th17 cell development. Taken together, our data indicate that exponential-phase S. aureus bacteria induce a stronger IL-12-dependent Th1 cell response than stationary-phase S. aureus and that this Th1 cell response shifted toward a Th17 cell response in the presence of PGN.

scholarly journals The mannophosphoinositides of Corynebacterium aquaticum

1975 ◽  
Vol 148 (2) ◽  
pp. 253-258 ◽  
Author(s):  
J A Hackett ◽  
P J Brennan
Keyword(s):  
Stationary Phase ◽  
Exponential Growth ◽  
Growth Cycle ◽  
Exponential Phase ◽  
Late Stationary Phase ◽  
Late Exponential Phase

Besides the monomannophosphoinositide previously reported in Corynebacterium aquaticum small amounts of other, apparently more glycosylated, mannophosphoinositides have been identified in stationary phase cells. Moreover, by labelling cells with [32P]Pi, phosphatidylinositol was found, comprising about 1.5% of the stationary-phase phospholipids. 2. Pulse-chase experiments performed on cells in the late exponential phase of growth further suggested the sequence phosphatidylinositol leads to monomannophosphoinositide as the first step in the biosynthesis of the mannophosphoinositides. 3. Di-and tri-mannophosphoinositides are apparently the main mannophosphoinositides present during exponential growth. Monomannophosphoinositide predominates only in late stationary phase; in the earlier stationary phase, phosphatidylinositol comprises 50% of the phosphoinositide lipid, and tetramannophosphoinositide constitutes much of the remainder. 4. The metabolism and functions of the mannophosphoinositides are discussed, particularly in relation to changes in their composition throughout the growth cycle.

scholarly journals Growth-phase dependence of susceptibility to antimicrobial peptides in Staphylococcus aureus

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1786-1797 ◽  
Author(s):  
Miki Matsuo ◽  
Yuichi Oogai ◽  
Fuminori Kato ◽  
Motoyuki Sugai ◽  
Hitoshi Komatsuzawa
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Surface ◽  
Antimicrobial Peptides ◽  
Stationary Phase ◽  
Surface Charge ◽  
Growth Phase ◽  
Exponential Phase ◽  
Dependent Manner ◽  
Phase Dependence ◽  
Cell Surface Charge

Bacterial cell surface charge is responsible for susceptibility to cationic antimicrobial peptides. Previously, Staphylococcus aureus dlt and mprF were identified as factors conferring a positive charge upon cell surfaces. In this study, we investigated the regulation of cell surface charge during growth. Using a group of S. aureus MW2 mutants, which are gene-inactivated in 15 types of two-component systems (TCSs), we tested dltC and mprF expression and found that two TCSs, aps and agr, were associated with dltC and mprF expression in a growth phase-dependent manner. The first of these, aps, which had already been identified as a sensor of antimicrobial peptides and a positive regulator of dlt and mprF expression, was expressed strongly in the exponential phase, while its expression was significantly suppressed by agr in the stationary phase, resulting in higher expression of dltC and mprF in the exponential phase and lower expression in the stationary phase. Since both types of expression affected the cell surface charge, the susceptibility to antimicrobial peptides and cationic antibiotics was changed during growth. Furthermore, we found that the ability to sense antimicrobial peptides only functioned in the exponential phase. These results suggest that cell surface charge is tightly regulated during growth in S. aureus.

scholarly journals Translocation of mycobacillin synthetase in Bacillus subtilis

1985 ◽  
Vol 225 (3) ◽  
pp. 639-643 ◽  
Author(s):  
N K Mukhopadhyay ◽  
S K Ghosh ◽  
S Majumder ◽  
S K Bose
Keyword(s):  
Protein Synthesis ◽  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Exponential Phase ◽  
High Rate ◽  
Synthetase Activity ◽  
Late Exponential Phase ◽  
Extracellular Release ◽  
Particulate Form ◽  
Membrane Bound

The extracellular release of mycobacillin from Bacillus subtilis first occurred in the medium at the onset of stationary phase and continued at a high rate even after 6 days. Mycobacillin synthetase activity appeared earlier than late-exponential phase in the cytosol of producer cells and was not sedimentable even at 105 000 g. The activity then quickly reached the maximum late in the stationary phase. With further increase in the age of the culture, the activity gradually disappeared from the cytosol, to reappear concomitantly in the membrane in an insoluble particulate form, even in absence of protein synthesis. The membrane-bound synthetase activity was sedimentable at 10 000 g and was fairly active even after 5 days.

Temporal Expression of Staphylococcal Enterotoxin H in Comparison with Accessory Gene Regulator–Dependent and –Independent Enterotoxins

2012 ◽  
Vol 75 (2) ◽  
pp. 238-244 ◽  
Author(s):  
ELŻBIETA LIS ◽  
MAGDALENA PODKOWIK ◽  
JAROSŁAW BYSTROŃ ◽  
TADEUSZ STEFANIAK ◽  
JACEK BANIA
Keyword(s):  
Stationary Phase ◽  
Expression Profile ◽  
Exponential Phase ◽  
Staphylococcal Enterotoxin ◽  
Enzyme Linked Immunosorbent Assay ◽  
Temporal Expression ◽  
Accessory Gene ◽  
Late Exponential Phase ◽  
Accessory Gene Regulator ◽  
First Time

Using sandwich enzyme-linked immunosorbent assay (ELISA), the production of staphylococcal enterotoxin (SE) H was determined in 22 Staphylococcus aureus isolates bearing the seh gene. Samples of supernatants were taken at four time points corresponding to exponential phase (optical density at 600 nm [OD600] 0.3 to 0.6), late exponential phase (OD600 2 to 4), early stationary phase (OD600 4 to 6), and late stationary phase (OD600 7 to 12). In four isolates, SEH was detectable at a very low level at the first time point. In 18 isolates, the earliest SEH production was detected in the late exponential phase. For all isolates, there was an increase of SEH concentration with time. Western blot analysis revealed that SEH production, similar to SEA, started in the early exponential phase (OD600 ~ 0.5). Isolates with high SEH productivity, as measured by ELISA, demonstrated a higher seh transcription as well. sec transcription was induced in the stationary phase. An induction in the sea transcript was observed during mid- to late exponential phase. Expression profile of seh was similar to that of sea. We showed that the seh expression profile is similar to that of Agr-independent sea and not to that of Agr-dependent sec genes. SEH can be effectively expressed at low bacterial counts, meaning that even in an environment not favorable for S. aureus growth, seh-bearing strains can pose a risk for food safety.

scholarly journals Role of mRNA Stability in Growth Phase Regulation of Gene Expression in the Group A Streptococcus

2006 ◽  
Vol 189 (5) ◽  
pp. 1866-1873 ◽  
Author(s):  
Timothy C. Barnett ◽  
Julia V. Bugrysheva ◽  
June R. Scott
Keyword(s):  
Gene Expression ◽  
Stationary Phase ◽  
Growth Phase ◽  
Group A Streptococcus ◽  
Exponential Phase ◽  
Northern Hybridization ◽  
Late Exponential Phase ◽  
Group A ◽  
Phase Regulation ◽  
The Stability

ABSTRACT The impressive disease spectrum of Streptococcus pyogenes (the group A streptococcus [GAS]) is believed to be determined by its ability to modify gene expression in response to environmental stimuli. Virulence gene expression is controlled tightly by several different transcriptional regulators in this organism. In addition, expression of most, if not all, GAS genes is determined by a global mechanism dependent on growth phase. To begin an analysis of growth-phase regulation, we compared the transcriptome 2 h into stationary phase to that in late exponential phase of a serotype M3 GAS strain. We identified the arc transcript as more abundant in stationary phase in addition to the sag and sda transcripts that had been previously identified. We found that in stationary phase, the stability of sagA, sda, and arcT transcripts increased dramatically. We found that polynucleotide phosphorylase (PNPase [encoded by pnpA]) is rate limiting for decay of sagA and sda transcripts in late exponential phase, since the stability of these mRNAs was greater in a pnpA mutant, while stability of control mRNAs was unaffected by this mutation. Complementation restored the wild-type decay rate. Furthermore, in a pnpA mutant, the sagA mRNA appeared to be full length, as determined by Northern hybridization. It seems likely that mRNAs abundant in stationary phase are insensitive to the normal decay enzyme(s) and instead require PNPase for this process. It is possible that PNPase activity is limited in stationary phase, allowing persistence of these important virulence factor transcripts at this phase of growth.

Wall turnover deficiency of Bacillus subtilis Nil5 is due to a decrease in teichoic acid

1987 ◽  
Vol 33 (6) ◽  
pp. 566-568 ◽  
Author(s):  
Ljubiša Vitković
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Stationary Phase ◽  
Phosphorus Content ◽  
Teichoic Acid ◽  
Exponential Phase ◽  
Standard Strain ◽  
Late Exponential Phase ◽  
Wall Teichoic Acid

Bacillus subtilis Ni15 is deficient in cell wall turnover. This deficiency is removed if the medium contains 0.2 M NaCl, which does not affect growth. The levels of amidase and glucosaminidase, the most likely enzymes involved in turnover, were, in stationary phase Nil5 cells, similar to those in late-exponential phase cells of a standard strain. The Nil5 enzymes were not salt sensitive. However, the Nil5 walls contained 4.7-fold less phosphorus than the walls of the standard strain. Since the phosphorus content of B. subtilis walls reflects the level of teichoic acid, it is proposed that the turnover deficiency of this strain is due to a decrease in wall teichoic acid.

scholarly journals Rot Repression of Enterotoxin B Expression in Staphylococcus aureus

2005 ◽  
Vol 187 (15) ◽  
pp. 5301-5309 ◽  
Author(s):  
Ching Wen Tseng ◽  
George C. Stewart
Keyword(s):  
Staphylococcus Aureus ◽  
Exponential Phase ◽  
Regulatory Pathway ◽  
Accessory Gene ◽  
Sensing System ◽  
Accessory Gene Regulator ◽  
Quorum Sensing System ◽  
Associated Proteins ◽  
Enterotoxin B ◽  
Repressor Activity

ABSTRACT The accessory gene regulator (Agr) system is a quorum-sensing system of Staphylococcus aureus responsible for upregulation of certain exoprotein genes and downregulation of certain cell-wall associated proteins during the post-exponential phase of growth. The enterotoxin B (seb) determinant is upregulated by the Agr system. Agr-regulated cis elements within the seb promoter region were examined by deletion analyses of the seb promoter by a hybrid promoter approach utilizing the staphylococcal lac operon promoter. To identify the regulatory pathway for enterotoxin B expression, the seb promoter fused to the chloramphenicol acetyltransferase reporter gene was introduced into mutants of S. aureus lacking agr or different members of the Sar family of transcriptional regulators. Agr control of seb promoter activity was found to be dependent upon the presence of a functional Rot protein, and Rot was shown to be able to bind to the seb promoter. Therefore, the Agr-mediated post-exponential-phase increase in seb transcription results from the Agr system's inactivation of Rot repressor activity.

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