Loeffelholz M J, Modrzakowski M C
Department of Zoological and Biomedical Sciences, Ohio University, Athens 45701.
Infect Immun. 1988 Mar;56(3):552-6. doi: 10.1128/iai.56.3.552-556.1988.
The antimicrobial mechanisms of rat polymorphonuclear leukocyte granule extract and isolated extract fractions against Acinetobacter calcoaceticus were examined. Crude granule extract and a fraction containing low-molecular-weight cationic peptides (peak D) reduced the viability of A. calcoaceticus and inhibited the uptake of radiolabeled macromolecule precursors by cells. The inhibitory activity observed with peak D was not as great as that of crude granule extract containing equivalent amounts of peak D protein. Crude extract also inhibited incorporation of uracil into trichloroacetic acid-precipitable material, while no isolated fraction, including peak D, had any substantial effect on incorporation. The antimicrobial activities of crude granule extract were more sensitive to boiling than those of isolated peak D. Preincubation of A. calcoaceticus with either crude granule extract or a fraction (peak B) possessing proteolytic activity but lacking any antimicrobial activity caused cells to become sensitive to a subinhibitory concentration of actinomycin D, suggesting that granule extract and peak B increase the outer membrane permeability of A. calcoaceticus. The antimicrobial granule extract fraction, peak D, did not affect outer membrane permeability. These results suggest that rat polymorphonuclear leukocyte granule extract reduces the viability of A. calcoaceticus by inhibiting the transport and incorporation of macromolecule precursors and that either whole granule extract is required for complete antimicrobial activity or an unidentified component is responsible for antimicrobial activity in addition to peak D. The granule extract activity that increases outer membrane permeability does not appear to be directly responsible for the observed decrease in viability.
研究了大鼠多形核白细胞颗粒提取物及其分离提取物组分对醋酸钙不动杆菌的抗菌机制。粗颗粒提取物和含有低分子量阳离子肽的组分（峰D）降低了醋酸钙不动杆菌的活力，并抑制了细胞对放射性标记大分子前体的摄取。观察到的峰D的抑制活性不如含有等量峰D蛋白的粗颗粒提取物的抑制活性强。粗提取物还抑制尿嘧啶掺入三氯乙酸可沉淀物质中，而包括峰D在内的任何分离组分对掺入均无实质性影响。粗颗粒提取物的抗菌活性比分离出的峰D对煮沸更敏感。将醋酸钙不动杆菌与具有蛋白水解活性但无任何抗菌活性的粗颗粒提取物或组分（峰B）预孵育，会使细胞对亚抑制浓度的放线菌素D变得敏感，这表明颗粒提取物和峰B增加了醋酸钙不动杆菌的外膜通透性。抗菌颗粒提取物组分峰D不影响外膜通透性。这些结果表明，大鼠多形核白细胞颗粒提取物通过抑制大分子前体的转运和掺入来降低醋酸钙不动杆菌的活力，并且要么完整的颗粒提取物是实现完全抗菌活性所必需的，要么除了峰D之外还有一种未鉴定的成分负责抗菌活性。增加外膜通透性的颗粒提取物活性似乎并非观察到的活力下降的直接原因。
