Toxins of staphylococcus aureus

The hemolysins of Staphylococcus aureus.

SUMMARY: Purified gamma haemolysin of Staphylococcus aureus was characterized in relation to the alpha, beta and delta haemolysins. The sedimentation coefficient of the gamma lysin was 2–65, somewhat higher than the s
20,w values of 1.4 for freshly purified alpha lysin and 1.8 for the beta lysin. The molecular weight of gamma lysin determined by gel filtration was 45000 daltons. The pI of gamma lysin was 6.0, while that of the alpha, beta and delta lysins ranged from 8.5 to 9.6.
The amino acid analysis of gamma lysin was characterized by low levels of methionine and histidine. Methionine was, however, the N-terminus, which suggested that all of the amino acid might be involved in the N-terminal group.
The gamma lysin was immunologically distinct from the alpha, beta and delta lysins by quantitative precipitin tests; in Ouchterlony agar gel diffusion tests, single lines of precipitation were observed which showed no evidence of cross-reactions amongst the four haemolysins.
Gamma, beta and delta lysins had no effect in mice when injected at increasing doses ranging from 0 to 100 μg. The alpha lysin killed mice, the LD50 dose being 0.68 ± 0.12 μg, or 27 to 34 μg/kg mouse tissue. Gamma lysin was, however, lethal for guinea pigs when 50 μg quantities were injected intracardially. Gamma lysin also lysed human leucocytes and destroyed C-6 (human lymphoblast) cells.
Some nitrogen and phosphorus was released from human erythrocyte membranes treated with gamma lysin, when compared to untreated cells, and the rate of this release was linear over a 3 h period. Gamma lysin had no detectable effect on phospholipids extracted from erythrocytes or on lipid-free membrane protein. However, the haemolytic reaction was inhibited by erythrocyte membranes when these were added to lysin-red cell suspensions. Furthermore, human red cell phospholipids competitively inhibited haemolysis. Haemolysis was also inhibited by EDTA and activity could be restored by dialysis. The haemolytic reaction required sodium ions.

Properties of the gamma haemolysin of Staphylococcus aureus 'Smith 5R'.

The enzymatic, toxic and molecular properties of sphingomyelinase from Bacillus cereuswere described in relation to other bacterial sphingomyelinases such as β-toxin of Staphylococcus aureus. The complete amino acid sequences of B. cereussphingomyelinase, determined from its chromosmal DNA, were examined in relation to other phospholipases C from B. cereusand Clostridium perfringens. The gene of B. cereussphingomyelinase codes 27 amino acid residues of signal peptide and 306 residues of mature protein. Both the genes of sphingomyelinase and phosphatidylcholine-hydrolyzing phospholipase C of B. cereusformed a gene cluster. According to the prediction of secondary structure of sphingomyelinase, almost half of the total amino acid residues might participate in loop or turn structure, while one-fifth and one-fourth of amino acid residues might be involved in α-helix and β-structure, respectively. The helical content determined by circular dichroism (CD) spectra indicated 0–5%. The enzyme specifically ...

Sphingomyelinase of Bacillus Cereusas a Bacterial Hemolysin

ブドウ球菌エンテロトキシンA, B, C2をSP-Sephadex C-25クロマトグラフィーおよびSephadex G-75ゲル〓過の2段階のみの簡易的かつ,ほぼ同一の方法で精製した。精製標品は,いずれもpH 4.3でのディスク電気泳動で1本のバンドを示し,また,それらをウサギに免疫して得られた抗血清との間に,それぞれ1本の沈降線を形成した。得られた抗血清は,粗毒素とも1本の沈降線のみを形成し,referenceエンテロトキシンと融合し,エンテロトキシンA, B, C2それぞれに特異的であつた。精製エンテロトキシンA, B, C2いずれにも,α-ヘモリジンおよびβ-ヘモリジンは認められなかつた。精製過程における回収率は73∼85%の間であつた。エンテロトキシンA, B, C2はいずれも,精製過程におけるSP-Sephadex C-25クロマトグラフィーで,複数のフラクションに分画されたが,それらのフラクションは免疫学的に均一であつた。エンテロトキシンA, B, C2のheterogeneityは,pH 9.5でのディスク電気泳動でもみられ,ゲル等電点電気泳動の結果から,エンテロトキシンAは,pI 6.5, 6.8, 7.2, 7.7, 8.3の各成分から,エンテロトキシンBは,pI 8.2, 8.5, 8.7, 8.9, 9.0, 9.1, 9.3の各成分から,またエンテロトキシンC2は,pI 6.2, 6.8, 7.3, 7.6の各成分からなつていることがわかつた。

SP-Sephadexクロマトグラフィーを用いたブドウ球菌エンテロトキシンA, B, C2の簡易精製

Purified staphylococcal nuclease and enterotoxin B from several sources contained beta hemolysin whose physicochemical resemblances to the other two proteins make its elimination difficult.

Vera Kucic

Papers

Beta hemolysin: a persistent impurity in preparations of staphylococcal nuclease and enterotoxin.