Although many of the mechanisms proposed for probiotic activity probably require growth and metabolism at the physiological site of action, confirmation of the requirement for viability through design of clinical studies with a non-viable control would clarify this issue.
Surprisingly, studies of Sno mutants in both flies and mice have proven enigmatic in revealing developmental roles for Sno proteins, particularly with regard to any requirement for viability.
Rapid growth thus may not be a biological sensible requirement for viability in many wild organisms.
Yet, as it is a strict maternal-effect lethal gene, its requirement for viability is apparent only in the embryo.
While we show that one functional copy of USP4 or USP15 is a minimum requirement for viability (Table 3), the observed departure from Mendelian ratios may arise from a functional deficiency in oocytes haploinsufficient for USP15.
In contrast, strains with the psd1Δ mutation alone or in combination with psd2Δ are not viable on lactate as a carbon source unless rescued by addition of 5 mM Etn to the medium as a minimum requirement for viability.
The requirement for viability of the β subunits of CK2 varies across species: disruption of the single metazoan β subunit is lethal in mice [ 20] and Caenorhabditis elegans [ 21], whereas disruption of either or both of the β subunits in Saccharomyces cerevisiae is not lethal [ 14, 22, 23].
These interactions may indicate a requirement for the transport of specific cargo(s) in the glc7-E101Q muthat tharearequiredred for viability.
While this level of quality and quantity is sufficient to demonstrate technical feasibility and reliability of prototype power applications, it cannot satisfy fully commercial requirements for economic viability.
