The number of reactive cysteine residues of yeast RNA polymerase I was determined and their function was studied using parachloromercury benzoate (pCMB), dithiobisnitrobenzoate (DTNB) and N-ethyl-maleimide (NEM) as modifying agents. By treatment with DTNB about 45 sulfhydryl groups react in the presence of 8M urea. Under non-denaturing conditions only 20 sulfhydryl groups are reactive with pCMB...

The [3H]thymidine uptake procedure for measuring lymphocyte responses was applied to lymphocytes derived concurrently from synovial effusions and from peripheral blood. The stimulating antigens were crude preparations of those micro-organisms that are related to the enteritis and the non-gonococcal urethritis that precipitate reactive arthritis. Salmonella, shigella, and campylobacter antigens ...