Differentiation between Clostridium acidiurici and Clostridium cylindrosporum on the basis of specific metal requirements for formate dehydrogenase formation

Abstract

The formate dehydrogenases of Clostridium acidiurici and of C. cylindrosporum coupled the oxidation of formate with the reduction of viologen dyes. The basal activity level was about 0.85 μmoles/min s mg of protein for both species. The level of formate dehydrogenase of C. acidiurici increased 12-fold when 10^-7 M tungstate and selenite were present during growth. Molybdate exerted no effect. On the other hand, molybdate and selenite were required to increase the formate dehydrogenase of C. cylindrosporum, and tungstate exhibited an antagonistic effect in this organism. Growth on hypoxanthine generally depended on the addition of bicarbonate. Supplementation with tungstate and selenite accelerated growth of C. acidiurici and increased again the level of formate dehydrogenase. The addition of both, molybdate and selenite was necessary to initiate growth of C. cylindrosporum and to form an active formate dehydrogenase. The differences in the requirement for metal ion supplementation to form high levels of formate dehydrogenase and their involvement in hypoxanthine degradation can be used to differentiate between C. acidiurici and C. cylindrosporum.