Heckly R J, Blank H
Appl Environ Microbiol. 1980 Mar;39(3):541-3. doi: 10.1128/aem.39.3.541-543.1980.
When equal volumes of 6% lactose and a broth culture of Yersinia pestis were mixed before freezing, approximately 50% of the cells survived lyophilization and reconstitution on the following day. Concomitantly, the number of viable cells per 50% lethal dose increased from about 16 to 125 organisms. On subsequent storage of the lyophilized cells under vacuum in glass ampoules at 4 degrees C for 25 years, more than 25% of the cells remained viable. When stored cultures were assayed immediately after reconstitution, virulence for mice was significantly reduced (as many as 4,000 cells/50% lethal dose), but the virulence was fully restored when reconstituted cultures were held for 24 h at room temperature, or when a subculture was prepared in fresh medium.
在冷冻前将等体积的6%乳糖溶液与鼠疫耶尔森氏菌的肉汤培养物混合时，约50%的细胞在冻干及次日复溶后存活。同时，每50%致死剂量的活细胞数从约16个生物体增加到125个。冻干后的细胞随后在玻璃安瓿中于4℃真空保存25年，超过25%的细胞仍保持存活。当对复溶后的保存培养物立即进行检测时，其对小鼠的毒力显著降低（多达4000个细胞/50%致死剂量），但当复溶后的培养物在室温下保存24小时，或在新鲜培养基中传代培养时，毒力可完全恢复。
