[Bacterial adjuvants in anti-influenza vaccine. I. Use of Micrococcus pyogenes var. aureus and of Streptococcus pyogenes].
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Antibodies↗
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Evidence for actinlike proteins in an M protein-negative strain of Streptococcus pyogenes.
Antigens shared between Streptococcus pyogenes and heart tissue may play an important role in autoimmune cardiac injury associated with acute rheumatic fever. Antiheart/antistreptococcal antibodies found in the disease react with antigens of S. pyogenes, including M protein and a 60-kDa antigen distinct from M protein. Heart antigens recognized by these cross-reactive antistreptococcal antibodies include myosin and actin. To investigate the presence of a streptococcal actin, established protocols for the polymerization and isolation of eukaryotic actin were used to extract and concentrate actinlike proteins from M- streptococcal cells. The polymerized bacterial actin from the streptococcal extract was probed in immunoblots with an antiactin monoclonal antibody. Two proteins of about 60 kDa in the polymerized bacterial actin reacted with the antiactin antibody. Proteins in the polymerized bacterial actin extract of about 43 and 60 kDa behaved like eukaryotic actin by binding to myosin and DNase I affinity columns. Filaments were demonstrated by electron microscopy in the polymerized bacterial actinlike extract, which also enhanced the ATPase activity of eukaryotic myosin. The data suggest that proteins resembling actin are present in S. pyogenes.
Actins↗
Cloning and characterization of the deoxyribonuclease sd alpha gene from Streptococcus pyogenes.
The pathogenesis of Streptococcus pyogenes infection, especially toxic shock-like syndrome (TSLS), is still not fully understood; however, the exoproteins have been considered to play a role. We analyzed the culture supernatant proteins (exoproteins) from a TSLS-related isolate belonging to M3 serotype S. pyogenes by two-dimensional gel electrophoresis and characterized a single protein spot by using BLAST database. We cloned the gene of this protein and named it sd alpha, which was similar to the deoxyribonuclease (DNase) sdc of S. equisimilis. We showed that the recombinant protein from the sd alpha gene had DNase activity. By polymerase chain reaction, we found that the sd alpha gene was present in most clinically isolated S. pyogenes including TSLS-related isolates. We thus conclude that Sd alpha is a new DNase of S. pyogenes.
Cloning, Molecular↗
MtsABC is important for manganese and iron transport, oxidative stress resistance, and virulence of Streptococcus pyogenes.
MtsABC is a Streptococcus pyogenes ABC transporter which was previously shown to be involved in iron and zinc accumulation. In this study, we showed that an mtsABC mutant has impaired growth, particularly in a metal-depleted medium and an aerobic environment. In metal-depleted medium, growth was restored by the addition of 10 microM MnCl(2), whereas other metals had modest or no effect. A characterization of metal radioisotope accumulation showed that manganese competes with iron accumulation in a dose-dependent manner. Conversely, iron competes with manganese accumulation but to a lesser extent. The mutant showed a pronounced reduction (>90%) of (54)Mn accumulation, showing that MtsABC is also involved in Mn transport. Using paraquat and hydrogen peroxide to induce oxidative stress, we show that the mutant has an increased susceptibility to reactive oxygen species. Moreover, activity of the manganese-cofactored superoxide dismutase in the mutant is reduced, probably as a consequence of reduced intracellular availability of manganese. The enzyme functionality was restored by manganese supplementation during growth. The mutant was also attenuated in virulence, as shown in animal experiments. These results emphasize the role of MtsABC and trace metals, especially manganese, for S. pyogenes growth, susceptibility to oxidative stress, and virulence.
ATP-Binding Cassette Transporters↗
HrcA is a negative regulator of the dnaK and groESL operons of Streptococcus pyogenes.
The genome of Streptococcus pyogenes, an important human pathogen, encodes homologs of the principal bacterial heat shock proteins DnaK and GroES, -EL, as well as HrcA, a negative regulator of dnaK and groESL expression in other Gram-positive bacteria. Using nuclease protection assays to measure dnaK/groESL mRNA abundance and a "non-polar" insertion to disrupt hrcA, we demonstrate that heat shock triggers a 4- to 8-fold increase in dnaK and groESL-specific mRNAs within 5 min of the temperature shift and that HrcA is a negative regulator of S. pyogenes dnaK/groESL mRNA abundance in unstressed S. pyogenes. Although the loss of HrcA elevated dnaK and groESL mRNA levels under non-heat shock conditions, the relative abundance of these RNAs increased further in heat shocked S. pyogenes, suggesting an additional element contributing to their synthesis or stability.
Bacterial Proteins↗
Rgg influences the expression of multiple regulatory loci to coregulate virulence factor expression in Streptococcus pyogenes.
The human pathogen Streptococcus pyogenes secretes many proteins to the cell wall and extracellular environment that contribute to virulence. Rgg regulates the expression of several exoproteins including a cysteine protease (SPE B), a nuclease (MF-1), a putative nuclease (MF-3), and autolysin. The functional heterogeneity of Rgg-regulated exoproteins and the lack of a conserved regulatory motif in the promoter regions of the genes suggested that Rgg interacts with additional regulatory networks to influence gene expression. DNA microarrays were used to test this hypothesis by comparing genomewide transcript profiles of S. pyogenes NZ131 and isogenic derivative NZ131 rgg during the exponential phase of growth. Transcripts of known and putative virulence-associated genes were more abundant in the rgg mutant, including emm, scpA, orfX, scl1, hasAB, slo, sagA, ska, speH, grab, mac, mf-1, and mf-3. Increased transcription of emm, scpA, and orfX in the rgg mutant was associated with increased production of the corresponding proteins. Differences in the expression of virulence-associated genes were associated with changes in the expression of several regulatory genes, including mga, sagA, csrRS, and fasBCA. The results show that Rgg influences the expression of multiple regulatory networks to coregulate virulence factor expression in S. pyogenes.
Bacterial Proteins↗
SclA, a novel collagen-like surface protein of Streptococcus pyogenes.
Surface proteins of Streptococcus pyogenes are important virulence factors. Here we describe a novel collagen-like surface protein, designated SclA (streptococcal collagen-like surface protein). The sclA gene was identified in silico using the Streptococcal Genome Sequencing Project with the recently identified protein GRAB as the probe. SclA has a signal sequence and a cell wall attachment region containing the prototypic LPXTGX motif. The surface-exposed part of SclA contains a unique NH(2)-terminal domain of 73 amino acids, followed by a collagen-like region. The sclA gene was found to be positively regulated by Mga, a transcriptional activator of several S. pyogenes virulence determinants. A mutant lacking cell wall-associated SclA was constructed and was found to be as effective as wild-type bacteria in platelet aggregation, survival in fresh human blood, and adherence to pharyngeal cells. The sclA gene was found in all 12 S. pyogenes strains that were investigated using PCR. Sequence analysis revealed that the signal sequence and the cell wall attachment region are highly conserved. The collagen-like domain is variable in its NH(2)-terminal region and has conserved repeated domains in its COOH-terminal part. SclA proteins from most strains have additional proline-rich repeats spacing the collagen-like domain and the cell wall attachment sequence. The unique NH(2)-terminal region is hypervariable, but computer predictions indicate a common secondary structure, with two alpha helices connected by a loop region. Immune selection may explain the hypervariability in the NH(2)-terminal region, whereas the preserved secondary structure implies that this region has a common function. These features and the Mga regulation are shared with the M protein of S. pyogenes. Moreover, as with the gene encoding the M protein, phylogenetic analysis indicates that horizontal gene transfer has contributed to the evolution of sclA.
Animals↗
Interaction between erythromycin and lincomycin in Streptococcus pyogenes.
Ten strains of Streptococcus pyogenes isolated were moderately resistant to erythromycin and highly but paradoxically resistant to lincomycin, and they showed antagonism between the two antibiotics. Another strain was moderately resistant to erythromycin and sensitive to lincomycin, and it showed synergism between the two antibodies.
Dose-Response Relationship, Drug↗
Hyporesponsiveness of peripheral blood lymphocytes to streptococcal superantigens in patients with guttate psoriasis: evidence for systemic stimulation of T cells with superantigens released from focally infecting Streptococcus pyogenes.
Throat infection with Streptococcus pyogenes is the most important trigger for acute guttate psoriasis. We examined the in vitro responses of peripheral blood mononuclear cells (PBMC) to streptococcal superantigens, SPEA and SPEC, and staphylococcal superantigens, SEB and TSST-1, in patients with guttate psoriasis, in patients with chronic plaque psoriasis, and in healthy subjects. PBMC from patients with guttate psoriasis responded poorly to SPEA and SPEC at concentrations of 0.1 and 1 ng/ml as compared with those from patients with plaque psoriasis, but showed high responses to SEB and TSST-1. The hyporesponsiveness recovered after improvement of the skin eruption. There was no significant difference between guttate and chronic types of psoriasis in the percentage of circulating T-cell receptor BV2 or BV8-bearing T cells, responsive to streptococcal superantigens, indicating that T-cell clonal anergy was a mechanism underlying the hyporesponsiveness. Our results suggest that superantigens released from focally infecting S. pyogenes induce a transient activation of relevant T cells, leading to the development of skin eruption and, subsequently, temporary T-cell anergy to these toxins.
Adult↗
[Isolation and study of the properties of Streptococcus pyogenes ribosomes].
Ribosomes from Streptococcus pyogenes, group A, strain 29 were studied. A comparison of different methods of ribosomal isolations has shown that the homogenous ribosomal samples can be obtained by the method of differential ultracentrifugation using tris-HCl buffer. The ribosomes of S. pyogenes had the sedimentation coefficient of 70S and consisted of 65% of protein and 35% of nucleic acids; the ribosomes dissociated into subparticles with the sedimentation coefficients of 50S and 30S under a low magnesium concentration. Thus the S. pyogenes ribosomes do not differ from the ribosomes of procaryotes. It was shown that the ratios of 70S, 50S and 30S ribosomal subparticles in the cells depend on the growth phase of S. pyogenes. The cells of the middle and the late logarithmic phase contained 50S and 30S particles in a stoichiometric ratio. In the cells of the late stationary growth phase there was a deficiency of 30S ribosomal subparticles which does not result from a loss during the isolation procedure, as it was already observed in the initial 30S fraction.
Cell Fractionation↗
In vitro development of resistance to six quinolones in Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus.
Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus isolates were exposed to subinhibitory MICs of ciprofloxacin, sparfloxacin, gatifloxacin, moxifloxacin, clinafloxacin, and gemifloxacin during a 10-day period. Subculturing led to resistance development, regardless of the initial potencies of the quinolones. None of the quinolones was associated with a significantly slower rate of resistance development.
Anti-Infective Agents↗
Specific binding of collagen type IV to Streptococcus pyogenes.
Many strains of Streptococcus pyogenes are capable of binding type IV collagen. In the present study, all 50 S. pyogenes strains isolated from patients with acute glomerulonephritis showed high or moderate affinity for radiolabelled type IV collagen. A majority of strains of other sources, such as reference strains of various M-types and strains isolated from patients with pharyngeal infections also bound type IV collagen; however, a number of weak binders or non-binders were found among those. The collagen type IV binding component(s) on S. pyogenes were susceptible to proteinase K digestion, partially sensitive to trypsin but insensitive to pepsin treatment at pH 5.5. According to tests with three M-positive strains and their M-negative derivatives, the binding was not dependent on M-protein. The binding was saturable with time and inhibited by unlabelled type IV collagen. Partially inhibition was found with type II collagen, gelatin and fibrinogen but not with a number of other serum proteins.
Collagen↗
Effect of SpeB and EndoS from Streptococcus pyogenes on human immunoglobulins.
Streptococcus pyogenes secretes a specific immunoglobulin G (IgG)-protease, SpeB, as well as the IgG glycan-hydrolyzing enzyme EndoS. Here we show that SpeB also degrades IgA, IgM, IgD, and IgE. We also show that EndoS only hydrolyzes the glycan moiety on native but not denatured IgG. Thus, SpeB has a broad immunoglobulin-degrading activity, while EndoS is highly specific for IgG.
Antibodies, Bacterial↗
Immunoelectron microscopic localization of T proteins in the cell wall of Streptococcus pyogenes.
T proteins of Streptococcus pyogenes (group A streptococci) were localized by means of immunochromatographical isolated anti-T-antibodies. For the electron microscopical detection both the direct and the indirect immunoferritin techniques were used. The arrangement of the ferritin particles showed, that the T proteins are evenly distributed on the whole cell surface. They are immediately bound to the outer layer of the cell wall or to only short filaments. On isolated cell walls the T protein was detected only on the outer surface.
Agglutination Tests↗
Purification and characterization of streptin, a type A1 lantibiotic produced by Streptococcus pyogenes.
Approximately 10% of Streptococcus pyogenes strains inhibit the growth of all nine indicators in a standardized streptococcal bacteriocin typing scheme. The present study has shown that this inhibitory profile, referred to as bacteriocin producer (P)-type 777 activity, is due to the type A1 lantibiotic streptin. Two major forms of streptin were purified to homogeneity from 95% acidified (pH 2) methanol extracts of S. pyogenes M25 cells by using a series of reversed-phase chromatographic separations. The fully processed form of streptin (streptin 1) is a 23-amino-acid peptide with a mass of 2,424 Da. The 2,821-M(r) form of the peptide (streptin 2) has three additional amino acids (TPY) at the N terminus. Strain M25 extracts also contained small quantities of the streptin 1 and streptin 2 peptides in various stages of dehydration. Streptin 1 and streptin 2 were each capable of specifically inducing streptin production when added to strain M25 cultures. The streptin gene cluster resembled that of other type A1 lantibiotics but appeared to lack a streptin-specific proteinase gene. Although the streptin structural gene (srtA) was widespread within S. pyogenes, being detected in 40 of 58 strains, each representing a different M serotype, only 10 of these srtA-positive strains produced active streptin. The failure of some strains to express streptin was attributed to an approximately 4.5-kb deletion in their streptin loci, encompassing genes putatively encoding proteins involved in streptin processing (srtB and srtC) and transport (srtT). In other strains, srtA transcription appeared to be defective. No direct association could be detected between the production of streptin and the production of the lantibiotic-like hemolysin streptolysin S in strain M25.
Amino Acid Sequence↗
Anionic lipids enriched at the ExPortal of Streptococcus pyogenes.
The ExPortal of Streptococcus pyogenes is a membrane microdomain dedicated to the secretion and folding of proteins. We investigated the lipid composition of the ExPortal by examining the distribution of anionic membrane phospholipids. Staining with 10-N-nonyl-acridine orange revealed a single microdomain enriched with an anionic phospholipid whose staining characteristics and behavior in a cardiolipin-deficient mutant were characteristic of phosphatidylglycerol. Furthermore, the location of the microdomain corresponded to the site of active protein secretion at the ExPortal. These results indicate that the ExPortal is an asymmetric lipid microdomain, whose enriched content of anionic phospholipids may play an important role in ExPortal organization and protein trafficking.
Anions↗
The role of iron in the growth and hemolysin (Streptolysin S) production in Streptococcus pyogenes.
Four strains of Streptococcus pyogenes were propagated at 37 degrees C in a reduced iron medium supplemented with Fe3+-citrate to give concentrations of 1 through 11 micrograms per milliliter, in order to observe the effects of iron on growth and on the vitro production of Streptolysin S. Both growth and hemolysin production were observed to be influenced by medium iron concentration of which 1.2 micrograms per ml of iron was critical. Hemolysin was produced during the exponential phase of the growth cycle with maximum yield as the organism entered the stationary phase. Hemolytic activity (which was accepted as the ability of the hemolysin to lyse sheep erythrocytes) fell below detectable levels as the organisms entered fully into the stationary phase (9-10 hours post incubation). Serum (bovine, human, chicken) was observed to have a high stabilizing effect on the hemolysin.
Bacterial Proteins↗
Extensive sequence homology between IgA receptor and M proteins in Streptococcus pyogenes.
Many strains of Streptococcus pyogenes are known to express a receptor for IgA. The complete nucleotide sequence of the gene for such a receptor, protein Arp4, has been determined. The deduced amino acid sequence of 386 residues includes a signal sequence of 41 amino acids and a putative membrane anchor region, both of which are homologous to similar regions in other streptococcal surface proteins. The processed form of the IgA receptor has a length of 345 amino acids and a calculated molecular weight of 39544. The N-terminal sequence of the processed form is different from that previously found for a similar IgA receptor isolated from a S. pyogenes strain of type M60. The sequence of protein Arp4 shows extensive homology to the C-terminal half of streptococcal M proteins, but not to the streptococcal IgG receptor protein G or staphlyococcal protein A. Apart from the membrane anchor, this homology includes a sequence of 119 amino acid residues containing three repeated units and a 54-residue sequence without repeats. The protein expressed in Escherichia coli is found in the periplasmic space, in which it constitutes the major protein. Protein Arp4 is the first example of a surface protein that has both immunoglobulin-binding capacity and structural features characteristic of M proteins.
Amino Acid Sequence↗