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Biomedical subjects

R S Anderson

Publications and source records attributed to R S Anderson.

At least 109 records · Page 6Linked to original sources

Novel properties of satellite DNA from muskmelon.

The purified dense satellite of muskmelon (Cucumis melo L.) represents 30% of the total DNA and forms a sharp, unimodal peak in both neutral and alkaline CsCl gradients. Spectrophotometric melting and DNA reassociation analyses revealed that one-third of the satellite is high melting and has a complexity of about 2.5 x 10(5) daltons, while the remaining two-thirds of the satellite melts 8 degrees lower and has a complexity of about 5 x 10(8) daltons. The thermal stability of reassociated satellite DNA indicates that the multiple copies of the two melting fractions are essentially identical. The sharp, unimodal peak in Cs(2)SO(4) becomes two distinct peaks when either silver or mercuric ions are included in the Cs(2)SO(4) gradient

Centrifugation, Density Gradient↗

Specific hemagglutinin and a modulator of complement in cockroach hemolymph.

Natural hemagglutinin activity against vertebrate erythrocytes is present in the hemolymph of the cockroach Blabarus craniifer. The hemagglutinin titer against rabbit erythrocytes is high, whereas sheep and horse red cells agglutinate weakly. Hemagglutinin activity was depressed by the complement inhibitor, cobra venom factor. Cockroach hemagglutinin is heat-labile; all activity is destroyed by heating at 56 C for 1 hr. A humoral factor similar to the complement component 3 proactivator is also present in cockroach hemolymph. The formation of the cobra venom factor-hemolymph "complex" is dependent on the presence of divalent cations and will not proceed at 56 C. The hemolytic intermediate formed after treatment of cockroach hemolymph with cobra venom factor was active in the presence of serum treated with ethylenediaminetetraacetic acid to inactivate the early complement components.

Agglutinins↗

Deoxyribonucleic acid relationships among marine vibrios.

The deoxyribonucleic acid (DNA) relationships of 80 strains identified either as Vibrio parahaemolyticus, V. alginolyticus, and V. anguillarum, or as allied marine vibrios were delineated by DNA-DNA competition experiments as well as by measuring the thermal stabilities of the DNA-DNA duplexes formed in direct binding studies. The tested strains included isolates from Japan, Europe, and the United States. The V. parahaemolyticus and V. alginolyticus groups showed an average of 67% homology to one another and 30% to strains of V. anguillarum. Significantly, a number of the isolates from the Pacific Northwest which had been previously identified as V. parahaemolyticus based on morphological, biochemical, and serological evidence were shown either to be strains of V. anguillarum or to belong to as yet unnamed groups. Most strains isolated from diseased salmon in the Pacific Northwest proved to be virtually identical with V. anguillarum type C by DNA homology experiments, thereby differentiating them from similar strains isolated from diseased herring and occasionally from salmon. The latter Pacific Northwest isolates fell into two distinct genotypic groups. A plot of the per cent homology by competition versus the difference in the thermal stabilities of heterologous and homologous duplexes (DeltaT(m,e)) between the same DNA species shows a linear decline in homology of 4.25% per degree of DeltaT(m,e). The use of this relationship for estimating the percentage of the mispaired bases distinguishing DNA preparations directly from competition experiments is discussed.

Adenine↗