Search PubMed⌕ Search

Biomedical subjects

K L Roy

Publications and source records attributed to K L Roy.

46 records · Page 3Linked to original sources
PubMed1976

Nucleotide sequence of 5 S ribosomal ribonucleic acid of Iguana iguana.

Cell cultures of the reptile Iguana iguana have been labeled with 32PO4(3-) and the resulting radioactive 5 S rRNA isolated. Enzymatic digests of the radioactive RNA were fractionated by standard procedures, and the products of the digestions sequenced. From the sequences of the oligonucleotides produced by enzymatic digestion of the Iguana 5 S rRNA it is possible to propose a primary sequence for this RNA which differs in only two positions (2 and 25) from the sequence known for mammalian 5 S rRNAs. This sequence is closer to that of mammals than is that of any other nonmammalian species yet examined.

Animals↗
PubMed1972

Macromolecular content of inclusions produced by a canine adenovirus.

Early inclusions induced by a canine adenovirus in a canine cell line, appearing before the formation of infectious virus particles, were purified by differential centrifugation in sucrose followed by CsCl density gradient centrifugation. Chemical analysis of these inclusions revealed that they contained deoxyribonucleic acid (DNA), ribonucleic acid, and protein. On the basis of density gradient centrifugation, the DNA extracted from the inclusions was found to be viral DNA. Electron microscope autoradiography showed that these inclusions were the sites of DNA synthesis. In addition, association of DNA polymerase activity with the inclusions was detected by incorporation of radioactivity from (3)H-thymidine triphosphate into a DNA product. The in vitro product of the enzyme had a density equal to that of viral DNA rather than host DNA. The level of DNA polymerase activity in exponentially growing infected and uninfected whole cells was similar, but in cells in stationary phase the enzyme activity of infected cells was twice that in noninfected cells. Furthermore, nuclei isolated from infected cells showed a fourfold increase in DNA polymerase activity over the noninfected cells.

Adenoviridae↗
PubMed1969

Cytokinins: distribution in transfer RNA species of Escherichia coli.

This distribution of cytokinin activity in tRNA species of Escherichia coli has been determined. Cytokinin activity was restricted to tRNA species recognizing codons with the initial letter U. The following have been shown to contain a cytokinin: tRNA(Phe), tRNA(Leu) UUG, tRNA(Ser)UC(G) (A), tRNA(Tyr), and tRNA(Try). tRNA(Cys) was present in fractions with cytokinin activity but was not sufficiently pure to prove it to be active. One tRNA(Ser) UC(C) (U) species was inactive. All major tRNA species recognizing condons with initial letters other than U were devoid of cytokinin activity in the tobacco bioassay. The significance of these findings is discussed as providing a possible mechanism of quantitative modulation at the translation stage of gene-controlled protein biosynthesis.

Cell Division↗
PubMedDate not supplied

Isolation and characterization of three cloned fragments of human DNA coding for tRNAs and small nuclear RNA U1.

Employing a human fetal liver library in lambda Charon 4A phage vector, we have isolated and characterized three clones of human DNA containing genes for tRNAs. One clone contains at least three tRNA genes (tRNALys, tRNAGln and tRNALeu) within 2 kb of each other. The other two clones contain two different single genes for tRNAAsn. One of these latter two DNAs also contains a gene for U1 small nuclear RNA.

Base Sequence↗