1. We have found that several members of the Actinomycetales (Micrococcus luteus, Rhodococcus rhodochrous and Mycobacterium tuberculosis and Mycobacterium smegmatis) can enter a "non-culturable" (NC) state when grown to and maintained in stationary phase in batch culture. These "non-culturable" organisms may be described as dormant, since they have extremely low metabolic activity and they require special treatment to promote their resuscitation. 2. In collaboration with Wales University, Aberystwyth (UK) we discovered a family of proteins involved in controlling dormancy and "non-culturability" in mycobacteria. Micrococcus luteus, a relative of M.tuberculosis, produces a "resuscitation-promoting factor" (Rpf) that is required to break the NC status of dormant organisms. Rpf homologues are widely distributed among the actinobacteria and multiple copies of rpf-like genes are found in M. tuberculosis as well as in other mycobacteria, corynebacteria and streptomycetes. Rpf resuscitates NC cells of M. tuberculosis as well as those of these other actinobacteria.

The laboratory is involved in study of mechanisms of bacterial cell response to different kind of stresses. In particular, we are interested in the mechanisms of cell survival under conditions of starvation and in stationary phase. The main attention is focused on formation of dormant and "non-culturable" cells of non-sporulating bacteria, their resuscitation and chemical and physical factors controlled these processes. Our current interest is associated with the study of dormant Mycobacteria tuberculosis (MTB) cells in connection with elucidation of mechanisms of latent tuberculosis. MTB, the causative agent of tuberculosis (TB), is responsible for more deaths than any other bacterial infectious disease. This organism is estimated to infect about one third of the Globe population. Nevertheless, ninety percent of these 2 billion people remain clinically healthy because persistent bacteria they harbor are quiescent, and these individuals never develop overt TB. Such latent infections are difficult to diagnose and treat. Latent infection in adults can reactivate at any time and is often accompanied by lung tissue destruction.