Isometric Forms Research Articles

Chelation of some bivalent metal ions by racemic and enantiomeric forms oftyrosine and tryptophan

Equlibrium constants are reported for the stepwise dissociation of protons from D-, L-, and DL-tyrosine and D-, L-, and DL-tryptophan, and the stepwise interaction of their ligand anions with Cd(II), Cu(II), Ni(II), Pb(II), and Zn(II) in aqueous solution at 20° and an ionic strength of 0.37 (NaNO 3). No differences have been observed either between the proton dissociation constants of the isometric forms of ligands or between the stability contants of the respective complex species (MD and ML, or MD 2, ML 2 and MLD).

CRYSTAL FORMATION IN CULTURES OF FUNGI. II. APPEARANCE OF CRYSTALS IN WHITE LIGHT.

The present study offers the picture of crystal formation in cultures of dermatophytes photographed in white light. Isometric and anisometric crystal forms are profusely depicted. ‘Pranks’ and ‘mimics’ of crystal forms are pointed out. Photomicrographic data are given.