Ureolytic Activity of the Washed Cell Suspension of Rumen Ciliate Protozoa

The Rumen Microbial Ecosystem

“…The rumen enzyme is probably similar to jackbean urease in its Ni content, jUdging by the stimulation of rumen urease activity by dietary Ni (Spears et aI., 1977;Spears and Hatfield, 1978). No urease activity was found in either starved, antibiotic-treated ciliate protozoa (Onodera et al, 1977) or in Piromyces or Neocallimastix fungal isolates . No urease activity was found in either starved, antibiotic-treated ciliate protozoa (Onodera et al, 1977) or in Piromyces or Neocallimastix fungal isolates .…”

Limits of Survival of the Mingled Rumen Bacteria in the Washed Cell Suspension of Rumen Ciliate Protozoa

“…But for the study of metabolic ability of rumen ciliates, incubation time should be elongated to 24 hr to avoid the effect of bacterial enzyme (even if bacteria are dead) such as urease which has a long-life as shown in our previous paper. 1 ) …”

Metabolism of Arginine, Citrulline, Ornithine and Proline by Starved Rumen Ciliate Protozoa

“…All these results led us to the conclusion that citrulline was produced as the first intermediate in arginine catabolism in the rumen ciliate protozoa as well as in that in the mixed rumen bacteria.!) Accordingly, the word 'arginase activity' used in the earlier report 6 ) should be changed to 'arginine-decomposing activity'…”

“…therefore, was also attributed to the hydrolysis of radioactive urea by the mingled bacteria in the ciliate suspension. 6 ) The present paper describes an attempt at the formation of urea and ammonia from some amino acids and further studies of thẽ etabolism of arginine and related compounds by the starved rumen ciliate suspension.…”

“…In this regard, most investigators 3 -S ) ruled out the possibility of ureolytic activity of rumen ciliates at the time and then we also examined their ureolytic activity and reached the conclusion that rumen ciliates themselves did not have ureolytic activity, because prolongation of the incubation time for' the ciliates in the buffer solution containing antibiotics rapidly reduced the activity, despite the fact that the initial washed ciliate suspension showed appreciable activity.6) On the other hand, viable counts of mingled bacteria in the washed suspension of rumen ciliates decreased with prolongation of the incubation time in the presence of antibiotics and eventually reached zero. 7 ) Thus the initial ureolytic activity of the washed ciliate suspension 6 ) was attributed to the mingled rumen bacteria in the suspension. 7 ) Production of radioactive carbon dioxide in the washed ciliate suspension,!)…”