A- and B-type hydrogen bond modifications of potassium hydrogen tartronate
ACCORDING to Speakman1 two types of intermolecular hydrogen bonds between carboxyl groups can be discerned in the crystal structures of acid salts of carboxylic acids. The first, type B, occurs when two carboxyl groups are not symmetry related, and have structural differences sufficient to characterise them, separately, as unionised (−CO2H) and ionised (−CO2−). Thus, any hydrogen bond between these groups must be asymmetric. The second, type A, occurs when two carboxyl groups are related by a symmetry element of the crystal, so that they are effectively equivalent. Thus any hydrogen bond between the groups must be, at least formally, symmetrical.
Analyse vibrationnelle et structurale de composés à pont disulfure II—structures et spectres de vibration du dithiodiglycolate acide de sodium et de potassium monohydratés à l'état cristallin
The structures of the potassium and sodium salts of dithiodiglycolic acid were determined on the basis of radiocrystallographic measurements. These compounds and their deuterated analogs were identified by spectral analysis. Assignments of the Raman and infrared lines in the range 4000–200 cm−1 show that for these acid salts, one form belongs to type pseudo-A and the second to type B according to Speakmann's classification. Copyright © 2001 John Wiley & Sons, Ltd.
PRODUCTION OF PASTEURELLA PESTIS TOXIN
In the course of the development of a casein hydrolyzate mineral glucose medium for the growth of Pasteurella pestis, strain A1122, for the production of the envelope antigen (Englesberg and Levy, 1954), the potential use of this medium for plague toxin production became apparent. The development of a simplified method for the production of plague toxin made possible by this medium will be described here.