identification and characterization of a spore-like morphotype in chronically starved mycobacterium avium subsp. paratuberculosis cultures识别和描述的spore-like形态类型在长期饥饿的鸟型分支杆菌无性系种群。.pdfVIP

Identification and Characterization of a Spore-Like Morphotype in Chronically Starved Mycobacterium avium Subsp. Paratuberculosis Cultures 1 4 ´ ´ 1 3 1,2 Elise A. Lamont , John P. Bannantine , Anıbal Armien , Don Sanjiv Ariyakumar , Srinand Sreevatsan * 1Veterinary Population Medicine, University of Minnesota, St. Paul, Minnesota, United States of America, 2 Department of Veterinary Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, United States of America, 3 Veterinary Diagnostic Lab, University of Minnesota, St. Paul, Minnesota, United States of America, 4 Agricultural Research Service, National Animal Disease Center, United States Department of Agriculture (USDA), Ames, Iowa, United States of America Abstract Mycobacteria are able to enter into a state of non-replication or dormancy, which may result in their chronic persistence in soil, aquatic environments, and permissive hosts. Stresses such as nutrient deprivation and hypoxia provide environmental cues to enter a persistent state; however, a clear definition of the mechanism that mycobacteria employ to achieve this remains elusive. While the concept of sporulation in mycobacteria is not novel, it continues to spark controversy and challenges our perceptions of a non-replication. We investigated the potential role of sporulation in one-year old broth cultures of Mycobacterium subsp. paratuberculosis (MAP). We show that dormant cultures of MAP contain a mix of vegetative cells and a previously unknown morphotype resembling a spore. These spore-like structures can be enriched for using sporulating media. Furthermore, purified MAP spore forms survive expos