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Biomedical subjects

M Rogolsky

Publications and source records attributed to M Rogolsky.

34 records · Page 2Linked to original sources
PubMed1974

Interaction of staphylococcal exfoliative toxin with concanavalin A.

Treatment of mouse embryo fibroblasts (MEF) grown in vitro with purified staphylococcal exfoliative toxin (ET) increased the concanavalin A (Con A) agglutinability of MEF 3.5-fold over control cells. Possible explanations for this phenomenon were investigated. ET lacked proteolytic activity on denatured casein. Con A, however, was found to interact directly with ET as evidenced by the formation of precipitation in an agar gel diffusion plate and in increased turbidity in solution. This interaction was inhibited by alpha-methyl-d-glucopyranoside. The ability of Con A to precipitate with ET suggests that the toxin contains a carbohydrate component and that the carbohydrate associated with ET is branched rather than linear. An analysis of a purified preparation of ET indicated the presence of 9% carbohydrate and no lipid.

Agglutination Tests↗
PubMed1974

Staphylococcal scalded skin syndrome: potentiation by immunosuppression in mice; toxin-mediated exfoliation in a healthy adult.

Staphylococcal scalded skin syndrome, associated with exfoliative toxin produced by phage group II Staphylococcus aureus, has recently been reported in an adult receiving immunosuppressive therapy. To determine the effect of immunosuppression on the development of the staphylococcal scalded skin syndrome, experimental animals were treated with prednisolone, azathioprine, or a combination of both drugs utilizing the clinical isolate from the adult with scalded skin syndrome. The mean lethal dose and mean exfoliating dose were identical and were 6,000-fold lower in animals receiving both drugs or azathioprine alone. The isolate was not more virulent and did not produce more toxin than other group II phage-type strains. Furthermore, immunosuppressive therapy failed to enhance the susceptibility of experimental animals to a purified preparation of toxin. Finally, purified exfoliative toxin was demonstrated to produce erythema, Nikolsky's sign, bullous formation, and flaking desquamation in a normal human adult. The results demonstrated the enhanced susceptibility of experimental animals receiving immunosuppressive therapy to the development of the staphylococcal scalded skin syndrome. They further showed that human adults are susceptible to the action of exfoliative toxin and suggested that, in the host with compromised defense mechanisms, toxin-producing strains may invade and initiate infection resulting in toxin production and exfoliation.

Adult↗
PubMed1974

Nature of the genetic determinant controlling exfoliative toxin production in Staphylococcus aureus.

Phage group II Staphylococcus aureus has been identified as the etiological agent of the staphylococcal scaleded skin syndrome. The development of an animal model system permitted fulfillment of Koch's postulates and recognition of exfoliative toxin (ET) as being responsible for some of the clinical manifestations of this syndrome. Initial studies directed toward associating a lysogenic phage with the genetic control of ET synthesis failed to support this hypothesis. Growth of two Tox(+) strains at 44 C was more effective than growth in ethidium bromide or sodium dodecyl sulfate in eliminating the ability to produce ET. The early and rapid accumulation of ET-negative (Tox(-)) variants during growth of strain UT 0007 at 44 C, the lack of any selective advantage of the Tox(-) variants over Tox(+) cells during growth at 44 C, and an enhanced elimination frequency at 44 C of 97.9% over the spontaneous frequency of loss strongly suggest that the gene for ET synthesis is extrachromosomal. Additional evidence suggests that this gene is located on a plasmid which is not associated with genes for penicillinase synthesis and cadmium resistance. Two Tox(+) strains harbored lysogenic phage capable of transducing cadmium resistance, but not penicillin resistance, to specific Tox(-) recipients.

Animals↗
PubMed1974

Effect of ethidium bromide on elimination of exfoliative toxin and bacteriocin production in Staphylococcus aureus.

The scalded skin syndrome has been associated with phage group II staphylococci. The clinical manifestations of scalded skin syndrome, Ritter's disease, scarlatiniform erythema, and localized bullous impetigo, are due to the production of an extracellular protein, designated exfoliative toxin. Phage group II staphylococci can also produce an extracellular protein, bacteriocin, which is bacteriocidal for specific gram-positive microorganisms. Strain UT 0007 produces both bacteriocin and exfoliative toxin which appear to be products of extrachromosomal genes. These genes are jointly eliminated from strain UT 0007 after growth in either ethidium bromide or at high temperatures.

Animals↗
PubMed1974

Sensitivity of an early step in the sporulation of Bacillus subtilis to selective inhibition by ethidium bromide.

When a final concentration of 0.4 mug of ethidium bromide (EB) per ml, which is subinhibitory to vegetative growth, is added to sporulating cells of Bacillus subtilis Marburg during either stage 0 or the early part of stage 1, morphogenesis is blocked. If the given concentration of EB is added after the early part of stage 1, sporogenesis is unaffected. The synthesis of the serine protease and antibiotic, which are believed to be associated with sporulation events during the early part of stage 0, are not inhibited by EB. Enhanced binding of [(14)C]benzylpenicillin to sporulating cells during septation (stage 2) is a measure of the presence of terminal enzymes for germ cell wall peptidoglycan synthesis. EB does not interfere with the binding of penicillin to sporulating cells, but penicillin remains more permanently bound to EB-treated postlogarithmic cells than to untreated sporulating cells. The absence of an interval of increased penicillin binding activity during stage 2 by sporulating cells treated with EB indicates that EB blocks sporulation prior to the completion of the germ cell wall.

Anti-Bacterial Agents↗
PubMed1973

Binding of radioactive benzylpenicillin to asporogenous mutants of Bacillus subtilis during postexponential growth.

The specific penicillin binding capacity of a postexponential culture of Staphylococcus aureus remains constant, but that of a sporulating Bacillus subtilis culture fluctuates dramatically. An initial decrease in binding capacity during presporulation events is followed by two distinct intervals of enhanced specific binding capacity during the postlogarithmic growth of a sporulating B. subtilis culture. The first peak of enhanced binding occurs during septation, when enzymes for germ cell wall formation are present; and the second peak coincides with cortical biosynthesis. The specific postlogarithmic binding capacities of a number of Spo(-) mutants of B. subtilis were examined to ascertain if specific asporogenous mutations altered the binding pattern observed with the wild-type organism. Four distinct postexponential binding patterns were recognized: (i) a low, constant binding capacity resembling the binding pattern of S. aureus, (ii) a decrease in binding capacity with no subsequent significant peaks, (iii) a decrease in binding capacity followed by a single peak corresponding to the first peak seen with the wild type, (iv) a pattern similar to the wild type. The fourth pattern was observed in a mutant blocked during stage III of sporogenesis which produced forespores that never became refractile. Mutations blocking either one or both periods of enhanced postlogarithmic binding were interspersed throughout a linkage group of spore genes next to lys-2 on the B. subtilis chomosome.

Bacillus subtilis↗
PubMed1971

Binding of radioactive benzylpenicillin to sporulating Bacillus cultures: chemistry and fluctuations in specific binding capacity.

The chemistry of the binding of (14)C-benzylpenicillin to sporulating cultures of Bacillus megaterium and B. subtilis is similar to that in a 4-hr vegetative culture of Staphylococcus aureus. Unlabeled penicillins prevent the binding of (14)C-benzylpenicillin, but benzylpenicilloic acid and benzylpenilloic acid do not. Bound antibiotic can be removed from cells with neutral hydroxylamine at 25 C. Sporulating cultures display two intervals of enhanced binding, whereas binding to stationaryphase S. aureus cells remains constant. The first period of increased binding activity occurs during formation of the spore septum or cell wall primordium development, and the second coincides with cortex biosynthesis.

Bacillus↗
PubMedDate not supplied

Relationship of staphylococcal conjugative plasmids to large gentamicin-resistance nonconjugative plasmids in clinical isolates of Staphylococcus epidermidis.

Self-mobilization of large plasmids was not observed in 15 of 15 strains of gentamicin-resistant (Gmr) Staphylococcus epidermidis clinical isolates that were taken from bacteremic newborns in a neonatal intensive care unit. Alternatively, nine Gmr Staphylococcus aureus clinical isolates, which were isolated along with the S. epidermidis strains, were all shown previously to contain Gmr conjugative plasmids. All of the nonconjugative strains had plasmids that were similar in size to the S. aureus conjugative plasmids. Transfer of seven of these nonconjugative plasmids by protoplast transformation indicated that they carried Gmr determinants. The rationale of these studies was to detect the presence of genes for conjugation (tra) on the large Gmr nonconjugative plasmids. It was thought that these plasmids might contain either defective or deleted tra gene sequences. To gain insight into these possibilities, a 6.3-kb probe, which contained a major tra gene region, was hybridized with EcoRI and XbaI digests of nonconjugative plasmid DNA. Hybridization occurred with only one of eight plasmids. It was concluded that seven of the large S. epidermidis plasmids were not self-transmissible because they lacked tra genes. However, pMH6502 contained an excess of tra gene regions compared to prototype conjugative plasmids and was still not self-transmissible.

Conjugation, Genetic↗