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Biomedical subjects

B R Thomas

Publications and source records attributed to B R Thomas.

48 records · Page 3Linked to original sources
PubMed1981

The structural basis of biological systems -- on the structures of transfer RNA and DNA and on some biological consequences.

Tetrahelix polynucleotide structure is important in biological systems. Though it is disputed there is firm evidence that transfer RNA has a tetrahelix structure and has the form of a simple cylinder. There is overwhelming chemical, biochemical and sequence evidence and the structure satisfies the constraints of the unit cell lattice. Tetrahelix structure also occurs in DNA and appears to be the most stable form and in many cases the naturally occurring form under physiological conditions. The consequences of tetrahelix structure clarify some longstanding problems such as the physical basis of supertwisting and of compact structure.

Codon↗
PubMed1981

On the chemical and structural basis of membrane transducer and receptor systems.

Evolution was based initially on polynucleotide systems. From these there developed the polynucleotide-based protein biosynthetic system. Membrane transducers are required by the most primitive cells and must have appeared at a very early stage. They would therefore also be expected to involve polynucleotides. There is substantial biochemical evidence for polynucleotide involvement in membrane transducers. There does not appear to be any reasonable alternative. Many biologically active substances show good matching to a polynucleotide receptor site that gives a good account of receptor function. There appears then to be no doubt that polynucleotides provide the basis of membrane transducers.

Biological Evolution↗
PubMed1978

Use of an internal standard in monitoring the bacterial degradation of crude oil.

Hexachloroethane is nonvolatile, insoluble in water, and apparently not toxic to or metabolized by bacteria. Its addition to cultures growing at the expense of crude oil thus provides an internal standard against which the rate of degradation of individual crude oil components can be conveniently and reproducibly measured.

Bacteria↗
PubMed1975

Sequence diagrams and the presentation of structural and evolutionary relationships among proteins.

Protein sequences mapped on two-dimensional diagrams show characteristic patterns that should be of value in visualising sequence information and in distinguishing simpler structures. A convenient map form for comparative purposes is the alpha-helix diagram with aminoacid distribution analogous to the surface of an alpha-helix oriented so that an alpha-helix structure corresponds on the diagram to a vertical band 3.6 residues wide. The sequence diagram for an alpha-keratin, high-sulphur protein suggests a new form of polypeptide helix based on a repeating unit of five which may be an important component of alpha-keratin fibres.

Amino Acid Sequence↗
PubMedDate not supplied

On the origin of protein biosynthesis.

There is a very close steric relationship between the codon-anticodon site which accounts for the genetic code dictionary and a polynucleotide replicase site. Protein biosynthesis must therefore have arisen out of a primaeval polynucleotide replicase system.

Anticodon↗
PubMedDate not supplied

Symptomatic hypocalcemia and hypoparathyroidism in two infants of mothers with hyperparathyroidism and familial benign hypercalcemia.

Neonatal hypocalcemia secondary to maternal hypercalcemia is relatively rare. We describe two infants with hypocalcemia and generalized seizures at 2 weeks and at 5 days of age, respectively. In the first case the infant was delivered of a mother who was subsequently diagnosed as having hyperparathyroidism. In the second case the infant was a member of a kindred with familial benign hypercalcemia. The evaluation of late-onset neonatal hypocalcemia should include an evaluation of maternal hyperparathyroidism and, in some cases, an evaluation for familial calcium disorders.

Female↗