Search PubMed⌕ Search

Biomedical subjects

S Kaplan

Publications and source records attributed to S Kaplan.

At least 541 records · Page 30Linked to original sources
PubMed1971

Localization of a portion of the ribosomal RNA genes in Escherichia coli.

About one-half of the genes coding for ribosomal RNA in Escherichia coli have been localized by the use of F-merogenotes. These cistrons have been positioned between 74 and 77 min on the E. coli map described by Taylor and Trotter. The episomal DNA carrying these genes was enriched by chromatography. The map position is discussed with reference to previous localization attempts.

Centrifugation, Density Gradient↗
PubMed1971

Lysine suppressor in Escherichia coli.

Head amber mutant of phage T4D was used to determine the efficiency of suppression and the amino acid inserted by Escherichia coli CA273 (sup-273 formerly Su(+) (beta)). The level of suppression determined was 8%, and the amino acid inserted was shown to be lysine.

Amino Acid Sequence↗
PubMed1971

Isolation and fractionation of the photosynthetic membranous organelles from Rhodopseudomonas spheroides.

Molecular sieve chromatography and sucrose gradient centrifugation were used to prepare large quantities of purified chromatophores from Rhodopseudomonas spheroides. Electron micrographs of these chromatophores revealed that the final preparations were very homogeneous and free of non-chromatophore particulate material. As an additional check on purity, (14)C-l-phenylalanine-labeled aerobic cells, devoid of chromatophores, were mixed with unlabeled photosynthetic cells. The resulting preparation contained less than 1% of the radioactivity, originally located in non-chromatophore protein. The purified chromatophores were solubilized in 2-chloroethanol and separated into two fractions. Fraction P(1) contained 3 to 5% of the total chromatophore protein and could be resolved into 10 electrophoretic components. The second fraction, P(II), contained five electrophoretic components. One of these components had associated with it all of the pigment and phospholipid present in P(II). Preliminary immunochemical studies on these fractions are also reported.

Alcohols↗