Gentry M J, Confer A W, Weinberg E D, Homer J T
Am J Vet Res. 1986 Sep;47(9):1919-23.
In studies of Pasteurella haemolytica type 1 cytotoxin, filter-sterilized culture supernatants from organisms grown in RPMI-1640 tissue culture medium generally have been used. Supplementation of the medium with 7% bovine fetal serum was shown to be necessary for maximal cytotoxin production, as measured by percentage of bovine peripheral blood leukocytes that were killed. The serum-induced increase in cytotoxicity could not be explained simply by a greater percentage of increase in the number of viable organisms produced in the enriched medium. There also was no correlation between encapsulation of the organisms and cytotoxin production. Several natural iron-containing proteins including transferrin, lactoferrin, conalbumin, and hemoglobin stimulated cytotoxin production in lieu of bovine fetal serum, leading to the conclusion that one function of serum supplementation may be to increase the medium's iron concentration. A number of additional iron-containing and iron-chelating compounds were tested, with the conclusion that the iron concentration of the growth medium, as well as the presence of a suitable carrier molecule, may be critical for efficient cytotoxin production by P haemolytica.
在对1型溶血巴斯德菌细胞毒素的研究中，通常使用在RPMI - 1640组织培养基中培养的细菌经滤菌器除菌后的培养上清液。通过被杀死的牛外周血白细胞的百分比来衡量，结果表明向培养基中添加7%的牛胎血清对于最大量产生细胞毒素是必要的。血清诱导的细胞毒性增加不能简单地用富集培养基中产生的活生物体数量增加的更大百分比来解释。生物体的荚膜形成与细胞毒素产生之间也没有相关性。包括转铁蛋白、乳铁蛋白、伴清蛋白和血红蛋白在内的几种天然含铁蛋白质可替代牛胎血清刺激细胞毒素产生，从而得出结论：补充血清的一个作用可能是提高培养基的铁浓度。测试了许多其他含铁和铁螯合化合物，得出的结论是，生长培养基的铁浓度以及合适载体分子的存在，对于溶血巴斯德菌有效产生细胞毒素可能至关重要。
