PURIFICATION AND CHARACTERIZATION OF STAPHYLOCOAGULASE

Effect of highly purified coagulase and culture filtrate on virulence and immunity of a coagulase-negative mutant of staphylococcus aureus BB

The virulence of the coagulase-deficient mutant BB-Cgl- 1301 (50% lethal dose [LD50] for mice by the intravenous route) was compared with that of its parental strain, Staphylococcus aureus BB. The BB strain produced free coagulase of serotype I, whereas the mutant 1301 did not. Mice were infected with strain 1301, alone or in combination with a highly purified coagulase type I or type II solution, or with concentrated culture filtrates of parent strain BB or mutant strain 1301. The ratios of the LD50S of 1301 and its combinations to that of BB ranged from 34.9 to 461. Combining strain 1301 with a concentrated culture filtrate of BB (BB-CF2.5) was the most effective for enhancement of its virulence. When mice were infected with a combination of strain 1301 and BB-CF2.5, the LD50 of strain 1301 (1.72 mg of cells [wet weight]) was decreased to 0.13 mg (1.3 x 10(8) CFU). This LD50 yielded the smallest ratio, 34.9, as compared with the LD50 of BB (0.00373 mg). In contrast, when the mice subcutaneously immunized with strain 1301 and BB-CF50 were intravenously challenged by strain BB, the LD50 for the immunized mice was 17.4 times the LD50 for the unimmunized control mice (0.0429 mg as compared with 0.00246 mg), indicating that combination was the most effective for enhancement of mouse immunization with strain 1301. However, combining strain 1301 with the highly purified sample of coagulase increased neither the virulence nor the immunizing power of mutant strain 1301.

Partial purification and characterization of the multiple molecular forms of staphylococcal clotting activity (coagulase)

The clotting activity of Staphylococcus aureus strain 104 was purified 46,000-fold, but absolute purity was not achieved. Carbohydrate content of the purified material was not more than 5%. Elution of clotting activity from denaturing and nondenaturing polyacrylamide gels revealed the presence of four distinct molecular forms. Molecular weights of the forms were approximately 31,500, 34,800, 44,800, and 56,800 as determined by gel filtration in 8 M urea, by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis, and by calculation with determined values for the Stokes radius and sedimentation coefficient. Molecular weights determined on sodium dodecyl sulfate-urea gels were found to decrease as the gel concentration increased, suggesting that the amount of sodium dodecyl sulfate bound was less than normal. Estimated frictional ratios for the forms showed that they differ in shape from one another and that they are all highly asymmetrical. Each of the forms had an isoelectric point between pH 5.44 and 5.47 when focused in 6% polyacrylamide gels for 9 h; however, prolonged focusing altered the isoelectric point of the forms to within the range of pH 4.35 to 4.65. The multiple clotting forms were not artifacts of the purification procedure and did not appear to be products of the proteolytic degradation of a larger protein.

Purification and properties of staphylocoagulase

Staphylocoagulase, an exoprotein of coagulase-positive Staphylococci, has been purified to a state in which only trace amounts of contaminating proteins are detectable. Aspartic acid was found as a single N-terminal amino acid in this preparation. The molecular weight is 61 000; the isoelectric point lies as pH 4.53. The amino acid composition was determined.

Release of beta-lysin from platelets by thrombin and by a factor produced in heparinized blood

Removal of calcium by either citrate, oxalate, or ethylenediaminetetraacetate inhibited coagulation of blood at an early stage and prevented the release of beta-lysin from platelets. In contrast, heparin caused platelet agglutination and stimulated beta-lysin release in vitro and in vivo. This release was calcium dependent and may have been due to a calcium-dependent reaction in the blood coagulation sequence. Thrombin which by-passed the early calcium-dependent stages of coagulation directly stimulated the release of beta-lysin from platelets. However, thrombin alone or in combination with other plasma factors was not as effective in releasing beta-lysin as the regular coagulation process. Thrombin's platelet degranulating activity correlated with its beta-lysin releasing activity. In contrast to thrombin, staphylococcal coagulase, which also by-passed the calcium-dependent stages of coagulation, coagulated citrated blood without releasing beta-lysin. The release of beta-lysin has been observed previously in the absence of blood coagulation, but this is the first observation of coagulation without beta-lysin release. It is clear that beta-lysin is released from platelets during coagulation by the direct action of thrombin and that it may be released in an earlier calcium-dependent reaction.

Coagulase production by injured Staphylococcus aureus MF-31 during recovery

Suspensions of Staphylococcus aureus MF-31 injured by heat treatment at 54 C for 15 min produced coagulase during recovery in Trypticase Soy Broth. Coagulase also was produced by injured cells during recovery in a medium that did not support growth. Coagulase synthesis during recovery was independent of the molar strength of the buffer in which the cells were injured, the age of the cells, and the degree of injury. Return of salt tolerance and coagulase production required glucose, amino acids, and phosphate in the recovery medium. Vitamins stimulated coagulase production, but did not affect recovery. Although coagulase production was not necessary for repair of thermal injury to S. aureus MF-31, its detection was interpreted as an indicator of protein synthesis.

Staphylococcal hyaluronate lyase: purification and characterization studies

Staphylococcal hyaluronate lyase (hyaluronidase) derived from a pathogenic strain of staphylococcus was purified by means of salt fractionation with ammonium sulfate and gel filtration through Sephadex G-100. Most of the enzyme activity from concentrated culture supernatant fluids of staphylococci was obtained in a fraction precipitated by 90 to 100% saturation with ammonium sulfate. A small amount of enzyme was also precipitated by 80 to 90% saturation with the salt. The hyaluronidase-rich fractions did not contain other staphylococcal enzymes, such as coagulase, protease, lipase, and staphylokinase. These enzymes were present in the original concentrates. Molecular sieving chromatography of the partially purified enzyme by filtration through Sephadex G-100 resulted in a further increase in specific enzyme activity. However, more than one active peak was obtained after gel filtration, thus suggesting that there may be more than one molecular form of the enzyme. Immunodiffusion in agar gel of the chromatographically purified enzyme fraction, with immune serum from rabbits injected with concentrated staphylococcal culture supernatant fluids, indicated that there was one major antigen. A similar antigen, giving reactions of identity with the purified material, was present in the original culture supernatant fluid.

Purification and properties of lysozyme produced by Staphylococcus aureus

A method based on cold ethyl alcohol fractionation at different pH levels and ionic strengths and on gel filtration on a Sephadex G-200 column was used to concentrate and purify lysozyme from the culture supernatant fluid of Staphylococcus aureus strain 524. The final, nondialyzable product exhibited a 163-fold rise in specific activity over that of the starting material. Staphylococcal lysozyme is a glycosidase which splits N-acetylamino sugars from the susceptible substrate. Staphylococcal lysozyme was shown to be similar to egg white lysozyme in its optimal temperature for reaction, optimal pH, activation by NaCl and Ca(++) ions, inhibition by sodium citrate and ethylenediaminetetraacetate, and inactivation by Cu(++) ions and sodium dodecyl sulfate. It differs from the egg white lysozyme in its temperature susceptibility range (staphylococcal lysozyme is inactivated at 56 C). It acts on whole cells and cell walls of Micrococcus lysodeikticus, murein from S. aureus 524, and cell walls of S. epidermidis Zak. The last substrate was not susceptible to the action of egg white lysozyme in the test system used. The mechanism of action of staphylococcal lysozyme seems to be analogous to that of egg white lysozyme; however, the biological specificity of the two enzymes may be different.