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J J Ferretti

Publications and source records attributed to J J Ferretti.

At least 37 records · Page 2Linked to original sources
PubMed1997

Bacteriophage T12 of Streptococcus pyogenes integrates into the gene encoding a serine tRNA.

The region of temperate bacteriophage T12 responsible for integration into the chromosome of Streptococcus pyogenes has been identified. The integrase gene (int) and the phage attachment site (attP) are found immediately upstream of the gene for speA, the latter of which is known to be responsible for the production of erythrogenic toxin A (also known as pyrogenic exotoxin A). The integrase gene has a coding capacity for a protein of 41457 Da, and the C-terminus of the deduced protein is similar to other conserved C-terminal regions typical of phage integrases. Upstream of int is a second open reading frame, which is capable of encoding an acidic protein of 72 amino acids (8744 Da); the position of this region in relation to int suggests it to be the phage excisionase gene (xis). The arms flanking the integrated prophage (attL and attR) were identified, allowing determination of the sequences of the phage (attP) and bacterial (attB) attachment sites. A fragment containing the integrase gene and attP was cloned into a streptococcal suicide vector; when introduced into S. pyogenes by electrotransformation, this plasmid stably integrated into the bacterial chromosome at attB. The insertion site for the phage into the S. pyogenes chromosome was found to be in the anticodon loop of a putative type II gene for a serine tRNA. attP and attB share a region of identity that is 96 bp in length; this region of identity corresponds to the 3' end of the tRNA gene such that the coding sequence remains intact after integration of the prophage. The symmetry of the core region of att may set this region apart from previously described phage attachment sites (Campbell, 1992), and may play a role in the biology of this medically important bacteriophage.

Amino Acid Sequence↗
PubMed1997

Temporal production of streptococcal erythrogenic toxin B (streptococcal cysteine proteinase) in response to nutrient depletion.

The effects of various growth conditions on the production of streptococcal erythrogenic toxin B (streptococcal pyrogenic exotoxin B [SPE B]) by Streptococcus pyogenes were analyzed. SPE B was detected in broth culture supernatant fluid only during the stationary phase of growth when glucose and other potential carbon sources were depleted from the medium. Additionally, SPE B production was inhibited when the concentration of glucose in the medium was maintained. These results suggest that SPE B is secreted under conditions of starvation and may be involved in nutrient acquisition.

Carbon↗
PubMed1997

Genetic diversity in temperate bacteriophages of Streptococcus pyogenes: identification of a second attachment site for phages carrying the erythrogenic toxin A gene.

Bacteriophage T12, the prototypic bacteriophage of Streptococcus pyogenes carrying the erythrogenic toxin A gene (speA), integrates into the bacterial chromosome at a gene for a serine tRNA (W. M. McShan, Y.-F. Tang, and J. J. Ferretti, Mol. Microbiol. 23:719-728, 1997). This phage is a member of a group of related temperate phages, and we show here that not all speA-carrying phages in this group use the same attachment site for integration into the bacterial chromosome. Additionally, other phages in the group use the same serine tRNA gene attachment site as phage T12 and yet do not carry speA. The evidence suggests that recombination between phage genomes has been an important means of generating diversity and disseminating virulence-associated genes like speA.

Attachment Sites, Microbiological↗
PubMed1996

Organization and nucleotide sequence of the Streptococcus mutans galactose operon.

The galactose operon encoding a repressor and genes for the Leloir pathway for galactose metabolism (galactokinase, galactose-1-phosphate-uridyl transferase and UDP glucose-4-epimerase) was located adjacent to the multiple sugar metabolism (msm) operon on the chromosome of Streptococcus mutans Ingbritt (serotype c) and the complete nucleotide sequence of this 5-kilobase region was determined. The Leloir pathway was induced by the presence of galactose in the growth medium or following the release of intracellular galactose after uptake and cleavage of alpha-galactosides by the multiple sugar metabolism system. Analysis of the mechanism of galactose transport confirmed the absence of a galactose-specific phosphotransferase system and suggested the presence of an inducible galactose permease. Evidence is presented that galactose transport is independent of the proton motive force and may be ATP-dependent.

Adenosine Triphosphate↗
PubMed1996

The multiple-sugar metabolism (msm) gene cluster of Streptococcus mutans is transcribed as a single operon.

The multiple-sugar metabolism (msm) locus of Streptococcus mutans constitutes a non-PTS sugar uptake system responsible for the transport and utilization of raffinose, melibiose and isomaltotrioses. While previous studies have used polar mutations to suggest that these genes are co-transcribed, there has not been evidence to support this. In this report we present direct evidence that the msm genes can be transcribed as a single operon.

Base Sequence↗
PubMed1996

Genetic and phenotypic diversity among isolates of Streptococcus pyogenes from invasive infections.

To determine if recent cases of invasive group A streptococcal disease were caused by strains with a unique characteristic, 117 isolates Streptococcus pyogenes from patients with a variety of diseases, including necrotizing fasciitis and toxic shock syndrome, were analyzed. Significant genomic heterogeneity was observed among selected isolates, as determined using pulsed-field gel electrophoresis. The frequency of the bacteriophage-associated streptococcal erythrogenic toxin genes A and C (speA and speC) among the isolates was 44% (49/112) and 34% (38/112), respectively. Forty-three percent of speA-positive isolates produced streptococcal erythrogenic toxin (SPE) A in vitro. Seventy-six percent (85/112) of isolates produced SPE B in vitro, and in contrast to SPE A, little variation in the concentration of SPE B in broth culture supernatants was detected. The genetic and phenotypic heterogeneity observed among isolates from recent cases of severe infection does not support a clonal basis for the resurgence of invasive streptococcal infections.

Bacterial Proteins↗
PubMed1996

Physical and genetic chromosomal map of an M type 1 strain of Streptococcus pyogenes.

A physical map of the chromosome of an M type 1 strain of Streptococcus pyogenes was constructed following digestion with three different restriction enzymes, SmaI, SfiI, and SgrAI, and separation and analysis of fragments by pulsed-field gel electrophoresis. The genome size of this strain was estimated to be 1,920 kb. By employing Southern hybridization and PCR analysis, 36 genes were located on the map.

Electrophoresis, Gel, Pulsed-Field↗
PubMed1995

High level expression of Streptococcus pyogenes erythrogenic toxin A (SPE A) in Escherichia coli and its rapid purification by HPLC.

The speA gene encoding streptococcal erythrogenic toxin A (SPE A) from Streptococcus pyogenes bacteriophage T12 was overexpressed in Escherichia coli under the control of the T7 promoter. Since most of the expressed protein was found in the periplasmic space, an osmotic shock extraction with 0.5 M sucrose resulted in a highly enriched preparation of SPE A. An additional two-step purification employing high pressure liquid chromatography resulted in a purified SPE A protein.

Bacterial Proteins↗
PubMed1995

Construction of a Streptococcus pyogenes recA mutant via insertional inactivation, and cloning and sequencing of the complete recA gene.

To facilitate future genetic studies with Streptococcus pyogenes (Sp), a recA mutant (Rec11) was constructed using a streptococcal integration vector carrying a PCR-derived internal recA fragment. The insertion of the plasmid in the mutant chromosome was identified by Southern hybridization. Resistance to UV and the ability to accept linear DNA transformation by Rec11 were greatly decreased, confirming its RecA phenotype. Using the PCR-derived fragment as a probe, we cloned and sequenced the complete Sp recA gene, which is highly homologous to the recA of S. pneumoniae and Lactococcus lactis.

Amino Acid Sequence↗
PubMed1995

The cloning, expression and sequence analysis of a second Porphyromonas gingivalis gene that codes for a protein involved in hemagglutination.

It has been suggested that Porphyromonas gingivalis may possess more than one hemagglutinin. We have previously reported the cloning of a gene (hagA) that encodes a hemagglutinin. In this study we report the cloning, characterization, and sequencing of a second gene (hagB) that encodes a protein that also appears to be involved in hemagglutination. Antiserum to the clone (ST 7) was found to inhibit hemagglutination by P. gingivalis 381, and hemagglutinating inhibition activity of anti-P. gingivalis antiserum was reduced by adsorption of the antiserum with cells of clone ST 7. Restriction mapping and Southern analysis indicates there is little or no DNA homology between this cloned 4.8-kb HindIII DNA fragment and a cloned hemagglutinin gene we have previously described. Minicell analysis of the cloned P. gingivalis chromosomal DNA fragment revealed that the major gene product is a 49-kDa protein. Immunoaffinity chromatography using purified rabbit immunoglobulin G against the cloned protein resulted in the purification of a major reactive 49- to 50-kDa protein from a P. gingivalis cell lysate. Nucleotide sequence analysis revealed the hagB open reading frame to be 1053 nucleotides in length with a mol% G+C of 59.9% coding for a protein of 350 residues with a calculated molecular weight of 39.375 kDa. This protein was also determined to be basic and hydrophilic and to contain a potential signal peptide. Comparison of both the nucleotide and derived amino acid sequences with computer-based databases did not reveal any significant homologies between habB and any other previously sequenced genes.

Adhesins, Bacterial↗
PubMed1995

Analysis of a second bacteriophage hyaluronidase gene from Streptococcus pyogenes: evidence for a third hyaluronidase involved in extracellular enzymatic activity.

The hyaluronidase gene (hylP2) from a second group A streptococcal bacteriophage was isolated from ATCC T-type-22 hyaluronidase-producing strain 10403, a strain known to produce increased amounts of extracellular hyaluronidase. Sequence analysis of hylP2 and alignment with the previously described bacteriophage hyaluronidase gene (hylP) showed a high degree of similarity; however, hylP2 had deletions of regions specifying 34 amino acids. Twenty-eight of the deleted amino acids were in a region of HylP containing a series of collagen-like Gly-X-Y repeating units. By employing primers for both hylP and hylP2, PCR amplification resulted in fragments of appropriate sizes in 97% of the strains tested, with some strains producing two fragments, indicating the presence of at least two phages. When the hylP2 gene was introduced via a plasmid vector into a non-hyaluronidase-producing Streptococcus pyogenes strain, this strain was still unable to produce extracellular hyaluronidase, although intracellular hyaluronidase was present. These results, along with the absence of a typical N-terminal signal peptide, indicate that HylP2 is unable to be secreted into the extracellular milieu. Examination of more than 100 strains for production of hyaluronidase showed that only 23% of the strains produced extracellular hyaluronidase. One of these strains (strain 10403) contains a single bacteriophage hyaluronidase gene (hylP2) which, when inactivated by allelic replacement, still produces large amounts of extracellular hyaluronidase. These results suggest the presence of a different hyaluronidase gene encoding a protein that is actively secreted into the extracellular milieu.

Amino Acid Sequence↗