Higerd T B, Baechler C A, Berk R S
J Bacteriol. 1969 Jun;98(3):1378-89. doi: 10.1128/jb.98.3.1378-1389.1969.
The bacteriocin from Pseudomonas aeruginosa, pyocin, consists of a contractile sheath and inner core reminiscent of T-even coliphage tails. Contraction of the outer sheath was found to be promoted by 0.5 m magnesium chloride, 1% Formalin, low pH, sonic treatment, and freezing or thawing or both. The contraction caused by 0.5 m magnesium chloride, however, was found to be reversible and occurred upon reduction of the salt concentration from 0.5 to 0.02 m. In addition, direct assay showed that pyocin activity was nearly proportional to the percentage of only uncontracted forms. Initial studies suggested that the adsorption of purified pyocin onto cell wall fragments from the sensitive indicator strain of P. aeruginosa occurs with the relaxed particle only and not with the contracted form. However, after adsorption, contraction occurred. Various morphological structures, such as tail fibers and base-platelike appendages, were also observed. Upon contraction, six tail fibers were observed on many particles, four of which appeared to originate from the sheath and two from the inner core. Polysheaths and polycores several hundred nanometers in length were also occasionally observed.
来自铜绿假单胞菌的细菌素——绿脓菌素，由一个可收缩的鞘和一个让人联想到T偶数大肠杆菌噬菌体尾部的内核组成。研究发现，0.5m的氯化镁、1%的福尔马林、低pH值、超声处理以及冷冻或解冻（或两者兼有）均可促进外鞘的收缩。然而，发现0.5m氯化镁引起的收缩是可逆的，当盐浓度从0.5m降至0.02m时就会发生收缩。此外，直接检测表明，绿脓菌素活性几乎仅与未收缩形式的百分比成正比。初步研究表明，纯化的绿脓菌素仅以松弛颗粒而非收缩形式吸附到来自铜绿假单胞菌敏感指示菌株的细胞壁片段上。然而，吸附后会发生收缩。还观察到了各种形态结构，如尾丝和基板状附属物。收缩时，在许多颗粒上观察到六条尾丝，其中四条似乎起源于鞘，两条起源于内核。偶尔也会观察到长度达数百纳米的多鞘和多核。
