Salt-sensitivity of σ(H) and Spo0A prevents sporulation of Bacillus subtilis at high osmolarity avoiding death during cellular differentiation.

The spore-forming bacterium Bacillus subtilis frequently experiences high osmolarity as a result of desiccation in the soil. The formation of a highly desiccation-resistant endospore might serve as a logical osmostress escape route when vegetative growth is no longer possible. However, sporulation efficiency drastically decreases concomitant with an increase in the external salinity. Fluorescence microscopy of sporulation-specific promoter fusions to gfp revealed that high salinity blocks entry into the sporulation pathway at a very early stage. Specifically, we show that both Spo0A- and SigH-dependent transcription are impaired. Furthermore, we demonstrate that the association of SigH with core RNA polymerase is reduced under these conditions. Suppressors that modestly increase sporulation efficiency at high salinity map to the coding region of sigH and in the regulatory region of kinA, encoding one the sensor kinases that activates Spo0A. These findings led us to discover that B. subtilis cells that overproduce KinA can bypass the salt-imposed block in sporulation. Importantly, these cells are impaired in the morphological process of engulfment and late forespore gene expression and frequently undergo lysis. Altogether our data indicate that B. subtilis blocks entry into sporulation in high-salinity environments preventing commitment to a developmental program that it cannot complete

Fasting therapy - an expert panel update of the 2002 consensus guidelines

Fasting for medical purpose (fasting therapy) has a long tradition in Europe and is established as a defined therapeutic approach in specialized fasting hospitals or within clinical departments for integrative medicine. In 2002, the first guidelines for fasting therapy were published following an expert consensus conference; here we present a revised update elaborated by an expert panel. Historical aspects and definitions, indications, methods, forms, and accompanying procedures of fasting as well as safety and quality criteria of fasting interventions are described. Fasting has shown beneficial effects in various chronic diseases with highest level of evidence for rheumatic diseases. Preliminary clinical and observational data and recently revealed mechanisms of fasting and caloric restriction indicate beneficial effects of fasting also in other chronic conditions such as metabolic diseases, pain syndromes, hypertension, chronic inflammatory diseases, atopic diseases, and psychosomatic disorders. Fasting can also be applied for preventing diseases in healthy subjects. In order to guarantee successful use of fasting and to ensure adherence of all safety and quality standards it is mandatory that all interventions during fasting are guided/accompanied by physicians/therapists trained and certified in fasting therapy