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G F Saunders

Publications and source records attributed to G F Saunders.

At least 163 records · Page 9Linked to original sources
PubMed1972

Compositional heterogeneity of human heterochromatin.

When human genome was fractionated by thermal elution chromatography, repetitious DNA was found in every arbitrary temperature segment. When these repetitious DNA families were used for in situ hybridization, the following conclusions were evident: (a) Unlike the case of mouse, where essentially all centromeric heterochromatins appear to be composed of one DNA family, human heterochromatin is composed of various DNA families. (b) Some human heterochromatin pieces, (e.g., that of chromosome 9) appear to have more heterogeneous composition than others (e.g., that of chromosome 1). (c) The highly repetitious human DNA fractions are located primarily at the centromeric and telomeric regions, but the interstitial regions also contain these fractions. (d) The more slowly reassociating repetitious sequences are distributed over the length of the chromatid, with a slight bias in favor of the telomeric regions. (e) The repetitious DNA fractions of higher (guanine + cytosine) content have less affinity for the centromeric regions.

Cells, Cultured↗
PubMed1968

Properties of 5-fluorouracil-containing ribonucleic acid and ribosomes from Bacillus subtilis.

Growth of a strain of Bacillus subtilis that requires uracil, thymine, adenine, and tryptophan in the presence of 5-fluorouracil (FU) results in the synthesis of ribonucleic acid (RNA) and ribosomes in which 55 to 65% of the RNA uracil has been replaced by the fluorine derivative. Examination of analogue-containing ribosomes by sucrose density gradient centrifugation and thermal denaturation studies suggests that, as far as the size, shape, and packing structure are concerned, extensive FU substitution has little or no effect. FU appears to replace uracil in RNA without selectivity for one RNA class over another, as determined by methylated albumin-kieselguhr column chromatography and sucrose density gradient centrifugation. The total amino acid content of the cells is markedly affected by growth in the presence of FU. The possibility of an FU effect on genetic translation is discussed.

Amino Acids↗
PubMed1966

Ribonucleic acid and ribosomes of Bacillus stearothermophilus.

Saunders, Grady F. (University of Illinois, Urbana), and L. Leon Campbell. Ribonucleic acid and ribosomes of Bacillus stearothermophilus. J. Bacteriol. 91:332-339. 1966.-The ability of some thermophilic bacteria to grow at temperatures as high as 76 C emphasizes the remarkable thermal stability of their crucial macromolecules. An investigation of the ribonucleic acid (RNA) and ribosomes of Bacillus stearothermophilus was conducted. Washed log-phase cells were disrupted either by sonic treatment or by alumina grinding in 10(-2)m MgCl(2)-10(-2)m tris-(hydroxymethyl)aminomethane buffer, pH 7.4 (TM buffer). Ultracentrifugal analysis revealed peaks at 72.5S, 101S, and 135S, with the 101S peak being the most prominent. By lowering the Mg(++) concentration to 10(-3)m, the ribosome preparation was dissociated to give 40S, 31S, and 54S peaks. These in turn were reassociated in the presence of 10(-2)m Mg(++) to give the larger 73S and 135S particles. When heated in TM buffer, Escherichia coli ribosomes began a gradual dissociation at 58 C, and at 70 C underwent a large hyperchromic shift with a T(m) at 72.8 C. In contrast, B. stearothermophilus ribosomes did not show a hyperchromic shift below 70 C; they had a T(m) of 77.9 C. The thermal denaturation curves of the 4S, 16S, and 23S RNA from both organisms were virtually identical. The gross amino acid composition of B. stearothermophilus ribosomes showed no marked differences from that reported for E. coli ribosomes. These data suggest that the unusual thermal stability of B. stearothermophilus ribosomes may reflect either an unusual packing arrangement of the protein to the RNA or differences in the primary structure of the ribosomal proteins.

Bacillus↗