Physiology: Characteristics in Semisynthetic and Chemically Defined Liquid Media 



Many of tliese complexes are reversible, e.g., the reactions with glucose and pyruvate (S), 

 but others may cause new stable compounds to form (7). Since aldehydes and keto compounds 

 are less reactive under acid conditions, the marked stimulation by pyruvate and alpha-ketoglu- 

 taric acid at pH 6.5 compared to 7.2 may be due to lower reactivity of the acids with cysteine at 

 pH 6.5. But the lower pH may also permit these acids to enter the cell more readily by shifting 

 the dissociation equilibrium to the side of the non-ionized acids. 



Although the LDB has shown sensitivity to citrate, malate, and acetate -recognized chelat- 

 ing agents of calcium, magnesium, and iron— pyruvate and alpha-ketoglutaric acid did not inhibit 

 growth even though their chelating effects were observed when certain experimental media were 

 being neutralized. 



In addition, the organism must attempt to utilize amino acids as a source of energy and 

 carbon, with pHs subsequently rising as higli as 8.2. These amino acid substrates appear to be 

 primarily serine and threonine. With the media we developed, the buffering effect of carbon 

 dioxide is significant and can in part explain the results observed in liquid shake cultures where 

 the CO; helped maintain an acid pH. However, carbon dioxide may have other functions and an 

 acid pH would be contrary to its solution as bicarbonate. 



Finally, the LDB appears to be quite sensitive to oleic acid; presumably this is the toxic 

 factor in agar which is reversed by adding either 1.0% starch or 0.2% charcoal (Norit A). How- 

 ever, our experience with purified Tween 80 and with certain inocula suggest that the LDB itself 

 may be a source of inhibiting fatty acids. Thus, with the excretion of a soluble lipase described 

 by W. B. Baine et al. (Personal communication), one can visualize the release of toxic fatty acids 

 from purified Tween 80 or from lysed cells of the inoculum. 



Nevertheless, in the simple, chemically defined medium (Table 2) without added vitamins, 

 oleic acid, and starch, 10 LDB strains tested have grown extremely well during several sequential 

 transfers. 



REFERENCES 



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2. Feeley, J.C, R.J. Gibson, G.W. Gorman. N.C. Langford. J.K. Rasheed. D.C. Mackel. and W.B. Baine. 1979. 

 CYE Agar: A primary isolation medium for the Legionnaires" disease bacterium. J. Clin. Micro. (In press). 



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4. Pine, L. 1955. Studies on the growth of liistoplasnia capsulatum. II. Growth of the yeast phase on agar 

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5. Pine, L. and C.L. Peacock. 1955. Reactions of fumaric acid with cysteine. J. Am. Chem. Soc. 77:31-53. 



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7. Schubert, M.P. 1936. Compounds of thiol acids with aldehydes. J. Biol. Chem. 114:341-350. 



8. Schubert, M.P. 1939. The combination of cysteine with sugars. J. Biol. Chem. 130:601-603. 



9. Slack, J.M. and M.A. Gerencser. 1975. Actinomyces, filamentous bacteria. //; Biology and Pathogenicity, pp. 

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