TABLE 3.

Effects of d-, l-, and dl-PIP on amounts of endogenous osmolytes in salt-stressed cultures of S. meliloti 102F34

Form of PIP addeda	Amt of accumulated osmolyte (nmol mg of protein−1) in cellsb
	Early exponential phase			Late exponential phase
	Glutamate	NAGGN	Trehalose	Glutamate	NAGGNc	Trehalosec
None	650	150	60	510	510	150
d-PIP	700	190	65	560	520	160
l-PIP	710	180	75	590	511	155
dl-PIP	690	190	60	1220	690	130

^aCultures were grown in LAS medium with 0.5 M NaCl plus the indicated isomeric form(s) of PIP (1 mM). 

^bCytosolic osmolytes in cells at early and late exponential phases of growth were quantified enzymically after 5 to 8 and 24 to 30 h of culture, respectively. Data are means of triplicate assays with standard deviations of less than 10%. 

^cSimilar levels of the indicated osmolyte were also found in cells at the stationary phase.