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PubMed2003

A fluoroquinolone induces a novel mitogen-encoding bacteriophage in Streptococcus canis.

This study investigated whether the recently recognized emergence of canine streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis (NF) might be partly attributed to the use of fluoroquinolones to treat Streptococcus canis infections in dogs. Both mitomycin and the fluoroquinolone enrofloxacin caused bacteriophage-induced lysis of S. canis strain 34, an isolate from a case of canine STSS and NF. Fluoroquinolone-evoked, bacteriophage-induced lysis occurred over a range of concentrations similar to those that would occur after treatment of dogs with these agents. To search for a possible bacteriophage-encoded streptococcal superantigen gene(s), a library of the 36.5 (+/-1.1)-kb bacteriophage, designated phisc1, was made by ligating 3- to 7-kb Tsp5091-digested phisc1 fragments into an EcoRI-digested lambdaZapII vector. Recombinants were screened for mitogenic activity by using canine peripheral blood lymphocytes. Of 800 recombinants screened, 11 recombinants with mitogenic effects were identified, and their inserts were sequenced. The highest homology of 11.6 kb of sequenced phisc1 DNA was to the completely sequenced Streptococcus pneumoniae bacteriophage MM1. Seven of the 11 phisc1 sequenced inserts contained a 552-bp open reading frame, scm, with 27% amino acid similarity to pokeweed (Phytolacca americana) mitogen. PCR showed this gene to be present in 22 of 23 S. canis isolates tested. Quantitative reverse transcription-PCR showed that bacteriophage induction was associated with a 58-fold enhancement of expression of this gene relative to that in a noninduced culture of a similar age. The presence of this gene on a fluoroquinolone-induced bacteriophage may explain the association observed between fluoroquinolone use in dogs and the development of canine STTS and NF.

Amino Acid Sequence↗
PubMed1973

Filamentous capsulated streptococci from the human respiratory tract. 3. Immunochemical studies of the cross-reactivity between the cell wall antigens of a filamentous streptococcus and of pneumococcus.

A cell wall-associated polysaccharide has been isolated from a noncapsulated mutant, 89R50, of the alpha-hemolytic filamentous streptococcus of provisional capsular type 89. Chemical analysis of the polysaccharide indicates that it consists of galactosamine, glucosamine, glucose, and phosphorus. Immunological cross-reactivity was observed between the streptococcal cell wall antigen and antibody to the cell wall-like capsular polysaccharide of pneumococcus. This cross-reactivity appears attributable to similarities in the teichoic acid moieties rather than in the mucopeptide moieties of the two polymers. No chemical or immunological differences were observed in the cell wall carbohydrate of the noncapsulated streptococcus, 89R50, and that of its capsulated progenitor. It is suggested that antibody to this cell wall polysaccharide might serve as a basis for grouping other filamentous strains of streptococci of diverse capsular types, the cell wall antigens of which show similar cross-reactivity with that of pneumococcus.

Antigens, Bacterial↗
PubMed2006

Identification of a secreted cholesterol-dependent cytolysin (mitilysin) from Streptococcus mitis.

We have detected a cholesterol-dependent cytolysin, which we have named mitilysin, in a small number of Streptococcus mitis isolates. We have sequenced the mitilysin gene from seven isolates of S. mitis. Comparisons with the pneumococcal pneumolysin gene show 15 amino acid substitutions. S. mitis appear to release mitilysin extracellularly. Certain alleles of mitilysin are not recognized by a monoclonal antibody raised to the related toxin pneumolysin. Based on enzyme-linked immunosorbent assay and neutralization assay results, one isolate of S. mitis may produce a further hemolytic toxin in addition to mitilysin. As genetic exchange is known to occur between S. mitis and Streptococcus pneumoniae, this finding may have implications for the development of vaccines or therapies for pneumococcal disease that are based on pneumolysin.

Amino Acid Sequence↗
PubMed1996

Role of the C terminus in antigen P1 surface localization in Streptococcus mutans and two related cocci.

The C terminus of the major surface protein P1 from Streptococcus mutans is composed of a hydrophilic domain, an LPNTGV motif, a hydrophobic domain, and a charged tail. These features are shared by surface proteins from many gram-positive coccal bacteria. To investigate the role of the C-terminal domains in antigen P1 surface localization, full-length and truncated P1 gene constructs, which were expressed on the shuttle vector pDL276, were transformed into the P1-negative mutant S. mutans SM3352, Streptococcus gordonii DL-1, and Enterococcus faecalis UV202. Transformants were tested for expression of P1 by enzyme-linked immunosorbent assaying and Western blotting. The results showed that full-length P1 was expressed by transformants of all three bacteria and was localized on the cell surface. A fusion protein composed of the Staphylococcus aureus fibronectin binding protein C terminus and the P1 protein N terminus was found to surface localize in S. mutans. Deletion of the entire C-terminal domains resulted in P1 being expressed in the culture supernatant. A P1 truncation, which carried only the hydrophilic domain at its C terminus, was found partially associated with the cell surface. This truncated P1 was readily removed from the isolated cell wall by hot sodium dodecyl sulfate-mercaptoethanol extraction. In contrast, the full-length P1 remained associated with the isolated cell wall after similar treatment, suggesting covalent linkages between the full-length P1 and the cell wall. The results described above showed that antigen P1 was anchored to the cell wall by its C-terminal domains probably via covalent linkages with the cell wall. The results also support a universal mechanism involving the C-terminal domains for protein surface localization among this group of gram-positive bacteria.

Amino Acid Sequence↗
PubMed1997

Cell wall anchoring of the Streptococcus pyogenes M6 protein in various lactic acid bacteria.

The M6 protein from Streptococcus pyogenes is the best-characterized member of a family of cell envelope-associated proteins. Based on the observation that the C-terminal sorting signals of these proteins can drive cell wall anchoring of heterologous unanchored proteins, we have cloned and expressed the emm6 structural gene for the M6 protein in various lactic acid bacteria (LAB). The emm6 gene was successfully expressed from lactococcal promoters in several Lactococcus lactis strains, an animal-colonizing Lactobacillus fermentum strain, Lactobacillus sake, and Streptococcus salivarius subsp. thermophilus. The M6 protein was efficiently anchored to the cell wall in all strains tested. In lactobacilli, essentially all detectable M6 protein was cell wall associated. These results suggest the feasibility of using the C-terminal anchor moiety of M6 for protein surface display in LAB.

Antigens, Bacterial↗
PubMed2000

Barriers to genetic exchange between bacterial species: Streptococcus pneumoniae transformation.

Interspecies genetic exchange is an important evolutionary mechanism in bacteria. It allows rapid acquisition of novel functions by transmission of adaptive genes between related species. However, the frequency of homologous recombination between bacterial species decreases sharply with the extent of DNA sequence divergence between the donor and the recipient. In Bacillus and Escherichia, this sexual isolation has been shown to be an exponential function of sequence divergence. Here we demonstrate that sexual isolation in transformation between Streptococcus pneumoniae recipient strains and donor DNA from related strains and species follows the described exponential relationship. We show that the Hex mismatch repair system poses a significant barrier to recombination over the entire range of sequence divergence (0.6 to 27%) investigated. Although mismatch repair becomes partially saturated, it is responsible for 34% of the observed sexual isolation. This is greater than the role of mismatch repair in Bacillus but less than that in Escherichia. The remaining non-Hex-mediated barrier to recombination can be provided by a variety of mechanisms. We discuss the possible additional mechanisms of sexual isolation, in view of earlier findings from Bacillus, Escherichia, and Streptococcus.

Base Pair Mismatch↗
PubMed2003

Genomic organization and molecular characterization of SM1, a temperate bacteriophage of Streptococcus mitis.

The direct binding of Streptococcus mitis to human platelets is mediated in part by two proteins (PblA and PblB) encoded by a lysogenic bacteriophage (SM1). Since SM1 is the first prophage of S. mitis that has been identified and because of the possible role of these phage-encoded proteins in virulence, we sought to characterize SM1 in greater detail. Sequencing of the SM1 genome revealed that it consisted of 34,692 bp, with an overall G+C content of 39 mol%. Fifty-six genes encoding proteins of 40 or more amino acids were identified. The genes of SM1 appear to be arranged in a modular, life cycle-specific organization. BLAST analysis also revealed that the proteins of SM1 have homologies to proteins from a wide variety of lambdoid phages. Bioinformatic analyses, in addition to N-terminal sequencing of the proteins, led to the assignment of possible functions to a number of proteins, including the integrase, the terminase, and two major structural proteins. Examination of the phage structural components indicates that the phage head may assemble using stable multimers of the major capsid protein, in a process similar to that of phage r1t. These findings indicate that SM1 may be part of a discrete subfamily of the Siphoviridae that includes at least phages r1t of Lactococcus lactis and SF370.3 of Streptococcus pyogenes.

Base Composition↗
PubMed2003

Genetic and biochemical characterization of the F-ATPase operon from Streptococcus sanguis 10904.

Oral streptococci utilize an F-ATPase to regulate cytoplasmic pH. Previous studies have shown that this enzyme is a principal determinant of aciduricity in the oral streptococcal species Streptococcus sanguis and Streptococcus mutans. Differences in the pH optima of the respective ATPases appears to be the main reason that S. mutans is more tolerant of low pH values than S. sanguis and hence pathogenic. We have recently reported the genetic arrangement for the S. mutans operon. For purposes of comparative structural biology we have also investigated the F-ATPase from S. sanguis. Here, we report the genetic characterization and expression in Escherichia coli of the S. sanguis ATPase operon. Sequence analysis showed a gene order of atpEBFHAGDC and that a large intergenic space existed upstream of the structural genes. Activity data demonstrate that ATPase activity is induced under acidic conditions in both S. sanguis and S. mutans; however, it is not induced to the same extent in the nonpathogenic S. sanguis. Expression studies with an atpD deletion strain of E. coli showed that S. sanguis-E. coli hybrid enzymes were able to degrade ATP but were not sufficiently functional to permit growth on succinate minimal media. Hybrid enzymes were found to be relatively insensitive to inhibition by dicyclohexylcarbodiimide, indicating loss of productive coupling between the membrane and catalytic subunits.

Amino Acid Sequence↗
PubMed2004

Characterization of LytA-like N-acetylmuramoyl-L-alanine amidases from two new Streptococcus mitis bacteriophages provides insights into the properties of the major pneumococcal autolysin.

Two new temperate bacteriophages exhibiting a Myoviridae (phiB6) and a Siphoviridae (phiHER) morphology have been isolated from Streptococcus mitis strains B6 and HER 1055, respectively, and partially characterized. The lytic phage genes were overexpressed in Escherichia coli, and their encoded proteins were purified. The lytAHER and lytAB6 genes are very similar (87% identity) and appeared to belong to the group of the so-called typical LytA amidases (atypical LytA displays a characteristic two-amino-acid deletion signature). although they exhibited several differential biochemical properties with respect to the pneumococcal LytA, e.g., they were inhibited in vitro by sodium deoxycholate and showed a more acidic pH for optimal activity. However, and in sharp contrast with the pneumococcal LytA, a short dialysis of LytAHER or LytAB6 resulted in reversible deconversion to the low-activity state (E-form) of the fully active phage amidases (C-form). Comparison of the amino acid sequences of LytAHER and LytAB6 with that of the pneumococcal amidase suggested that Val317 might be responsible for at least some of the peculiar properties of S. mitis phage enzymes. Site-directed mutagenesis that changed Val317 in the pneumococcal LytA amidase to a Thr residue (characteristic of LytAB6 and LytAHER) produced a fully active pneumococcal enzyme that differs from the parental one only in that the mutant amidase can reversibly recover the low-activity E-form upon dialysis. This is the first report showing that a single amino acid residue is involved in the conversion process of the major S. pneumoniae autolysin. Our results also showed that some lysogenic S. mitis strains possess a lytA-like gene, something that was previously thought to be exclusive to Streptococcus pneumoniae. Moreover, the newly discovered phage lysins constitute a missing link between the typical and atypical pneumococcal amidases known previously.

Amino Acid Sequence↗
PubMed1961

Nutrition of Streptococcus bovis in relation to dextran formation.

Barnes, Isabel J. (Cornell University, Ithaca, N. Y.), H. W. Seeley, and P. J. VanDeMark. Nutrition of Streptococcus bovis in relation to dextran formation. J. Bacteriol. 82:85-93. 1961.-Three nutritional types of Streptococcus bovis were encountered. Minimal media for their growth are described. Transferable growth in defined media was always accompanied by dextran production and the nutrition for dextran production could not be distinguished from the minimal nutritional requirements of the organism for growth. Measurable, free CO(2) was evolved from a complex medium during the growth of S. bovis. Several compounds were found to replace partially the CO(2) requirement of the species. When fractured cell preparations containing S. bovis dextran were employed as antigens, rabbits failed to yield sera which would precipitate S. bovis or leuconostoc dextrans.

Dextrans↗
PubMed1961

Utilization of sulfur compounds by Streptococcus bovis.

Prescott, J. M. (A. &. M. College of Texas, College Station). Utilization of sulfur compounds by Streptococcus bovis. J. Bacteriol. 82:724-728. 1961.-Two strains of Streptococcus bovis utilize a variety of compounds as their only source of sulfur, yet exert a definite selectivity in their nutritional requirements for this element. Among sulfur-containing amino acids and related compounds, cystine and cysteine support excellent growth, but cysteic acid and cysteine sulfinic acid do not; methionine is completely inactive as an only sulfur source, but growth is provided by lanthionine, djenkolic acid, allo-cystathionine, homocystine, homocysteine, and glutathione. Several organic sulfur compounds other than amino acids are effective sulfur sources, among which are thioglycolate, thiomalate, thiourea, and thiouracil. In contrast, thiodiglycolate, thiodiglycol, and (phenylthio) acetic acid fail to support growth. Of the inorganic sulfur sources tested, sulfide and thiosulfate are utilized, but sulfite and sulfate are not; it thus appears that the state of oxidation is a critical factor in the utilization of sulfur by these strains of S. bovis. A complex amino acid mixture, without sulfur-containing amino acids, produces more rapid and reproducible growth than either arginine or ammonium acetate when used as a nitrogen source for testing the sulfur compounds. Growth rates are frequently better when the sulfur sources are autoclaved than when they are sterilized by filtration, although the qualitative responses to the compounds are generally similar.

Alanine↗
PubMed1963

IDENTIFICATION OF GROWTH STIMULANTS FOR STREPTOCOCCUS LACTIS.

Koburger, J. A. (North Carolina State College, Raleigh), M. L. Speck, and L. W. Aurand. Identification of growth stimulants for Streptococcus lactis. J. Bacteriol. 85:1051-1055. 1963-The growth of Streptococcus lactis in milk was accelerated by pancreas extract, and three distinct components that were detected by bioautography were isolated and identified. These were purified by precipitation with silver ions, and their silver salts were regenerated in acidic solution. After adsorption and elution from characoal, contaminating alpha-amino compounds were destroyed by treatment with ninhydrin. Final purification was by chromatography. Identification of the purified fractions was by paper chromatography, and by ultraviolet and infrared spectra. The active compounds were found to be inosine, hypoxanthine, and adenine.

Acids↗
PubMed1963

ROLES OF CITRATE AND ACETOIN IN THE METABOLISM OF STREPTOCOCCUS DIACETILACTIS.

Harvey, R. J. (University of California, Davis), and E. B. Collins. Roles of citrate and acetoin in the metabolism of Streptococcus diacetilactis. J. Bacteriol. 86:1301-1307. 1963.-Streptococcus diacetilactis was unable to use citrate as a source of energy for growth, but the addition of citrate to a lactose-containing medium increased the specific growth rate 35%. Besides serving as the precursor of acetoin, some of the pyruvate formed from citrate was incorporated into cell material, primarily into lipids. A constant fraction of the weight of new cells was synthesized from the pyruvate formed from citrate. The rate of entry of citrate into cells was independent of the growth rate, and the usual result was that more pyruvate was formed from citrate than was required for cell synthesis. All excess pyruvate was converted to acetoin. Thus, acetoin formation acts as a detoxification mechanism, a means of removing intracellular pyruvate not required for synthesis of cell material.

Acetoin↗
PubMed1964

EXTRACELLULAR PROTEINASE OF STREPTOCOCCUS LACTIS.

Williamson, W. T. (North Carolina State of the University of North Carolina, Raleigh), S. B. Tove, and M. L. Speck. Extracellular proteinase of Streptococcus lactis. J. Bacteriol. 87:49-53. 1964.-Streptococcus lactis was shown to produce an extracellular proteolytic enzyme(s). A 120-fold purification of the proteinase was obtained from the cell-free culture medium by ammonium sulfate fractionation, calcium phosphate gel treatment, and chromatography on diethylaminoethyl cellulose. Only 32% of the activity was destroyed by heating at 98 C for 1 hr. The requirement of free sulfhydryl groups for enzyme activity was indicated by inhibition with p-chloromercuric benzoate. Diisopropyl fluorophosphate did not inhibit the proteinase.

Benzoates↗
PubMed1964

GLYOXYLATE FERMENTATION BY STREPTOCOCCUS ALLANTOICUS.

Valentine, R. C. (University of Illinois, Urbana), H. Drucker, and R. S. Wolfe. Glyoxylate fermentation by Streptococcus allantoicus. J. Bacteriol. 87:241-246. 1964.-Extracts of Streptococcus allantoicus were found to degrade glyoxylate, yielding tartronic semialdehyde and CO(2). Tartronic semialdehyde was prepared chemically, and its properties were compared with the enzymatic product: reduction by sodium borohydride yielded glycerate; heating at 100 C yielded glycolaldehyde and CO(2); autoxidation yielded mesoxalic semialdehyde; periodate oxidation yielded glyoxylate and a compound presumed to be formate. Tartronic semialdehyde reductase was present in extracts of S. allantoicus and in a species of Pseudomonas grown on allantoin. A scheme for the synthesis of acetate from glyoxylate by S. allantoicus is discussed.

Acetates↗
PubMed1964

ELECTROPHORETIC SEPARATION OF CONSTITUENTS OF PARTIALLY PURIFIED M PROTEIN OF STREPTOCOCCUS PYOGENES.

Pierce, William A., Jr. (Tulane University, New Orleans, La.). Electrophoretic separation of constituents of partially purified M protein of Streptococcus pyogenes. J. Bacteriol. 88:912-921. 1964.-Partially purified M protein of a group A, type 12 strain of Streptococcus pyogenes was studied by use of chemical, electrophoretic, and immunological techniques. It was demonstrated in immunodiffusion tests that the antigen contains multiple precipitating components. The type-specific antigen was identified, and evidence was presented that, in some instances at least, the cross-reactions observed between this type 12 M protein and heterologous antisera in immunodiffusion tests involve contaminating antigens rather than the component which precipitates with adsorbed homologous-typing antiserum. In passive hemagglutination tests where M protein was adsorbed to tanned sheep erythrocytes, it was found that antisera suitably adsorbed to show good specificity in capillary precipitin tests nevertheless still contain cross-reactive antibodies which are detectable by this more sensitive technique. Electrophoresis on starch paste separates some of the components of partially purified M protein, so that a fraction can be obtained which has fewer precipitating antigens, as determined in immunodiffusion tests, and which is less cross-reactive in passive hemagglutination tests with heterologous unadsorbed antistreptococcal antisera.

Animals↗
PubMed1964

PURIFICATION AND PROPERTIES OF N-ACETYL-D-GLUCOSAMINE KINASE FROM STREPTOCOCCUS PYOGENES.

Zeleznick, L. D. (CIBA Pharmaceutical Co., Summit, N.J.), H. Hankin, J. J. Boltralik, H. Heymann, and S. S. Barkulis. Purification and properties of N-acetyl-d-glucosamine kinase from Streptococcus pyogenes. J. Bacteriol. 88:1288-1295. 1964.-A kinase from Streptococcus pyogenes which catalyzes adenosine triphosphate-dependent phosphorylation of d-glucose and N-acetyl-d-glucosamine has been purified 1,500-fold. The ratio of the enzymatic activity on both substrates remained constant throughout the fractionation. Similarity in heat stability, p-hydroxymercuribenzoate inhibition, protection by either carbohydrate, and lack of repression of enzymatic activity when the bacteria were grown exclusively on one of the two substrates supports the hypothesis that kinase activity is associated with one enzyme.

Acetylglucosamine↗
PubMed1965

BETA-GALACTOSIDASE OF STREPTOCOCCUS LACTIS.

Citti, J. E. (Oregon State University, Corvallis), W. E. Sandine, and P. R. Elliker. beta-Galactosidase of Streptococcus lactis. J. Bacteriol. 89:937-942. 1965.-Synthesis of beta-galactosidase by several strains of Streptococcus lactis was induced by lactose. The rate of hydrolysis of o-nitrophenyl-beta-d-galactopyranoside was used to measure enzyme activity. The enzyme of all but one strain was unstable when whole cells were sonic-treated or treated with toluene; the enzyme of one strain of S. lactis was stable to these treatments, which resulted in at least a fivefold increase in activity over that found in whole cells. The optimal assay conditions for toluene-treated cells of this strain involved incubation at 37 C in pH 7.0 sodium phosphate buffer. Lactose was the most effective inducer of enzyme synthesis. Methyl-beta-d-thiogalactopyranoside, isopropyl-beta-d-thiogalactopyranoside, and galactose were also inducers of the enzyme, but were not as effective as lactose. Melibiose, maltose, and calcium lactobionate were poor inducers of enzyme synthesis. Exogenously supplied glucose repressed enzyme synthesis. The means of control of induced beta-galactosidase synthesis in S. lactis was similar to that in Escherichia coli.

Disaccharides↗