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Comparative Study of the Ribosomal RNA from Leishmania and Trypanosoma 1
Author(s) -
Villalba Elena,
Dorta Bias,
Ramírez José Lues
Publication year - 1985
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.1550-7408.1985.tb03012.x
Subject(s) - ribosomal rna , rna , microbiology and biotechnology , dna , biology , molecular mass , density gradient , gel electrophoresis , 5s ribosomal rna , differential centrifugation , nucleic acid thermodynamics , kinetoplast , leishmania , biochemistry , 18s ribosomal rna , enzyme , parasite hosting , gene , physics , quantum mechanics , world wide web , computer science
The ribosomal RNA from several stocks of the genera Leishmania and Trypanosoma were studied by gel electrophoresis, sedimentation on sucrose density gradients and RNA/DNA hybridization experiments. Three major components were observed after electrophoresis in polyacrylamide gels (PAGE‐SDS), the relative molecular masses being respectively: X 1 = 0.83 megadaltons, X 2 = 0.63 megadaltons and X 3 = 0.54 megadaltons for Leishmania RNA; and X 1 = 0.86 megaldaltons, X 2 = 0.78 megadaltons, and X 3 = 0.58 megadaltons for Trypanosoma RNA. Depending upon the isolation procedure, a fourth component. X 0 = 1.2 megadaltons (26S), became evident. The later component was purified from Leishmania brasiliensis (Y) by centrifugation on a linear 15‐30% sucrose density gradient. This component, after heat denaturation and PAGE‐SDS, gave rise to two bands coinciding in molecular mass with those of X 2 and X 3 indicating that these components are part of the large ribosomal subunit whereas X 1 belongs to the small one. The above mentioned differences in mobilities of components X 1 and X 2 between the two genera were no longer observed after electrophoresis in denaturing agarose‐formaldehyde gels, suggesting secondary structural differences among these RNA species. Hybridization experiments with L. brasiliensis (Y) DNA showed that both RNA types compete equally well for the ribosomal sites in this DNA, and that L. brasiliensis (Y) rRNA recognizes the ribosomal sites in DNA of Trypanosoma cruzi (EP), thus indicating that no gross changes occurred in their nucleotide sequences during evolution.