VITAMINS 195 



1942) and by Memnoniella echinata and Stachyhotrys atra (Perlman, 

 1948). There is also evidence (Stokes et al., 1947) that biotin plays a 

 role in the synthesis of aspartic acid by certain bacteria. Thus, it appears 

 probable that one of the functions of biotin is connected with the synthesis 

 of aspartic acid. When aspartic acid is added to the medium, it is 

 unnecessary for the organism to perform this synthesis and the need for 

 biotin is greatly reduced. However, it should be noted that, although 

 the absolute amount of biotin needed is reduced, exogenous biotin is still 

 required by these biotin-deficient organisms. From this it may be 

 deduced that biotin has a multiple role in the cell. 



INOSITOL 



meso-Inositol (also known as inactive inositol, isoinositol, inosite, or 

 dambose) is widely distributed in both plants and animals. It was first 

 isolated in 1850. It was not until 1928 that Eastcott (1928) showed that 

 it was a growth factor for a strain of yeast. Later, Woolley (1940) 

 recognized it as a vitamin for animals. meso-Inositol is a hexahydroxy- 

 cyclohexane. It has the following configuration: 



H H 



Q Q 



OH/i i\ H 



1/ OH 0H\| 



c c 



:\ H OH/1 

 H \| 1/ OH 



C C 



OH li 

 meso-Inositol 



There are seven different cis-trans isomers, which are optically inactive, 

 and a pair of optically active d and I forms. The available evidence 

 indicates that the stereochemical configuration of weso-inositol is specific 

 for vitamin activity. Some of the isomers have only slight activity. 

 Inositol is active only in high concentrations as compared to the other 

 vitamins. The usual amount added is around 5 mg. per hter of medium. 



Fungi deficient for inositol. Many strains of yeast are deficient for 

 this vitamin, while others are not. In most cases the deficiency appar- 

 ently is partial rather than total. Partial deficiencies for various yeasts 

 are reported by Leonian and Lilly (1942), Burkholder (1943), and Burk- 

 holder and Moyer (1943). In the last two references total deficiencies 

 for inositol are reported for Saccharomyces uvarum Y 969 and Schizosac- 

 charomyces pomhe. 



Kogl and Fries (1937) were apparently the first to investigate the 

 action of inositol on various filamentous fungi. They found that Nemato- 

 spora gossypii was totally deficient and that Lophodermium pinastri was 



