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Induced Resistance to Sulfonamides in Chilomonas paramecium
Author(s) -
Hall R. P.
Publication year - 1957
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1957.tb02482.x
Subject(s) - sulfanilamide , thymine , biology , chemistry , reversion , microbiology and biotechnology , biochemistry , phenotype , dna , gene
SUMMARY. Strains of Chilomonas paramecium differing in degree of resistance to sulfanilamide have been established through acclimatization to this sulfonamide at 50, 100 and 200 mg. %. Resistant strains differ from the normal stock in their enhanced sensitivity to p ‐aminobenzoic acid. In the normal stock, sulfanilamide inhibition is reversed at an SA/PABA ratio of 10,000 but not at 20,000; in the least resistant strain, at a ratio of 400,000 but not at 800,000. In resistant strains inhibition is reversed by folk acid, methionine, adenine, cytosine and thymine; in the normal stock, none of these metabolites produces reversal. In high concentrations of PABA (10–20 mg. %) growth of the normal stock is only retarded, whereas the strain least resistant to sulfanilamide fails to recover from exposure to 20 mg. % PABA. The strain most resistant to sulfanilamide is most susceptible to PABA in high concentrations. The data suggest that resistance to sulfanilamide in C. paramecium may depend mainly upon an accelerated synthesis of PABA.