Rahman I, Shahamat M, Kirchman P A, Russek-Cohen E, Colwell R R
Department of Microbiology, University of Maryland at College Park 20742.
Appl Environ Microbiol. 1994 Oct;60(10):3573-8. doi: 10.1128/aem.60.10.3573-3578.1994.
A pathogenic strain of Shigella dysenteriae type 1 was selected for study to elucidate the physiology and potential pathogenicity of organisms in the viable but nonculturable (VBNC) state in the environment. Studies in our laboratory have shown that S. dysenteriae type 1 survives in laboratory microcosms in the VBNC state for long periods of time, i.e., more than 6 months. VBNC cells of S. dysenteriae type 1 were found to retain cytopathogenicity for cultured HeLa cells. To determine whether VBNC S. dysenteriae type 1 expressed protein after loss of culturability, 35S-labelled methionine was added to suspensions of VBNC cells. Total cellular proteins were extracted and examined by autoradiography. Results indicate that VBNC S. dysenteriae type 1 is capable of both active uptake of methionine and incorporation of methionine into protein. Amino acid uptake and protein synthesis substantiate the viability of cells of S. dysenteriae type 1 in the VBNC state, i.e., although the cells are unable to be cultured on laboratory media by standard bacteriological methods, the cells remain metabolically active. Furthermore, VBNC cells of S. dysenteriae type 1 may pose a potential public health hazard that has not yet been recognized.
选择1型痢疾志贺氏菌的一个致病菌株进行研究，以阐明环境中处于活的但不可培养（VBNC）状态的生物体的生理学和潜在致病性。我们实验室的研究表明，1型痢疾志贺氏菌在实验室微观环境中以VBNC状态存活很长时间，即超过6个月。发现1型痢疾志贺氏菌的VBNC细胞对培养的HeLa细胞保持细胞致病性。为了确定VBNC状态的1型痢疾志贺氏菌在丧失可培养性后是否表达蛋白质，将35S标记的甲硫氨酸添加到VBNC细胞悬液中。提取总细胞蛋白并通过放射自显影检查。结果表明，VBNC状态的1型痢疾志贺氏菌能够主动摄取甲硫氨酸并将甲硫氨酸掺入蛋白质中。氨基酸摄取和蛋白质合成证实了VBNC状态下1型痢疾志贺氏菌细胞的活力，即虽然这些细胞不能通过标准细菌学方法在实验室培养基上培养，但它们仍保持代谢活性。此外，1型痢疾志贺氏菌的VBNC细胞可能构成尚未被认识到的潜在公共卫生危害。
