Endospores
The small number of Bacterial genera most significantly Bacillus and Clostridium, are able to form spores within the cytoplasm in response to cell starvation. These endospores have been shown to be able to survive desiccation for centuries and their formation is discussed in detail in. The ability of endospores to survive radiation, heat and chemical disinfectants coupled to the  pathogenic nature of some members of Clostridium and Bacillus have led to the efficient sterilization procedures developed for medicine and bacteriology.