Biomedical subjects

T C Elleman

Publications and source records attributed to T C Elleman.

5 recordsLinked to original sources

PubMed1992

Production of Neisseria gonorrhoeae pili (fimbriae) in Pseudomonas aeruginosa.

Pseudomonas aeruginosa K/2PfS, when transformed with an expression plasmid harboring the pilin gene (pilE1) of Neisseria gonorrhoeae MS11, was able to express and assemble gonococcal pilin monomers into surface-associated pili, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, immunoblotting, and immunoelectron microscopy. Concomitant with the expression of gonococcal pili in P. aeruginosa was the virtual loss of production of P. aeruginosa K/2PfS pili normally associated with the host cell.

Amino Acid Sequence↗

PubMed1978

Amino acid sequences of alpha-helical segments from S-carboxymethylkerateine-A. Statistical analysis.

The distribution of the different types of amino acid residue within two helical segments isolated from the low-sulphur fraction of wool keratin was examined for periodicity and larger sequence repeats. Both were detected, the former corresponding to the geometry of the proposed coiled=coil structure and the latter suggesting a distant gene duplication, though the existence of the repeat might equally well be related to interactions within the microfibril.

Amino Acid Sequence↗

PubMed1978

A method for detecting distant evolutionary relationships between protein or nucleic acid sequences in the presence of deletions or insertions.

A method for detecting homology between two protein or nucleic acid sequences which require insertions or deletions for optimum alignment has been devised for use with a computer. Sequences are assessed for possible relationship by Monte Carlo methods involving comparisons between the alignment of the real sequences and alignments of randomly scrambled sequences of the same composition as the real sequences, each alignment having the optimum number of gaps. As each gap is successively introduced into a comparison (real or random) a maximum score is determined from the similarity of the aligned residues. From the distribution of the maximum alignment scores of randomly scrambled sequences having the same number of gaps, the percentage of random comparisons having higher scores is determined, and the smallest of these percentage levels for each pair of sequences (real or random) indicates the optimum alignment. The fraction of the comparisons of random sequences having percentage levels at their optimum alignment below that of the real sequence comparison at its optimum estimates the probability that such an alignment might have arisen by chance. Related sequences are detected since their optimum alignment score, by virtue of a contribution from ancestral homology in addition to optimised random considerations, occupies a more extreme position in the appropriate frequency distribution of score than do the majority of optimum scores of randomly scrambled sequences in their appropriate distributions. Application of this 'optimum match' method of sequence comparison shows that the sensitivity of the 'maximum match' method of Needleman and Wunsch (1970) decreases quite dramatically with sequence comparisons which require only a few gaps for a reasonable alignment, or when sequences differ greatly in length. The 'maximum match' method as applied by Barker and Dayhoff (1972) has the additional disadvantage that deletions which have occurred in the longer of two homologous protein sequences further decrease the sensitivity of detection of relationship. The 'constrained match' method of Sankoff and Cedergren (1973) is seen to be misleading since large increments in the alignment score from added gaps do not necessarily result in a high total alignment score required to demonstrate sequence homology.

Amino Acid Sequence↗

PubMed1978

Isolation, characterization and pathology of the toxin from a Microcystis aeruginosa (= Anacystis cyanea) bloom.

The nature of the toxicity of a bloom of blue-green alga, M. aeruginosa (= Anacystis cyanea), that occurred in a man-made lake was investigated. Crude algal bloom extracts were toxic to laboratory mice when injected intraperitoneally. The lethal dose (LD100) of these extracts was 15-30 mg of lyophilized algal bloom per kilogram body weight. The toxin was purified by a procedure that included ammonium sulphate fractionation, solvent extraction, acid precipitation, Sephadex G25 and DEAE-Sephadex chromatography, and high-voltage electrophoresis at pH 6.5. The preparation gave a single spot on high-voltage electrophoresis at pH 9.0, had no free amino group, and was characterized by a simple amino acid composition of equimolar quantities of L-methionine, L-tyrosine, D-alanine, D-glutamic acid, erythro beta-methyl aspartic acid and methylamine. The LD50 for the purified toxin was estimated to be 0.056 mg/kg of mice, and the approximate LD100 is 0.070 mg/kg, based on the total material found from amino acid analysis. Parenteral administration of the purified toxin to mice produced extensive liver lobular haemorrhage and death within 1-3 h. Repeated inoculation of sublethal doses daily over some weeks produced progressive hepatocyte degeneration and necrosis and the development of fine hepatic fibrosis.

Amino Acids↗

PubMed1977

Amino acid sequence of the smaller subunit of conglutin gamma, a storage globulin of Lupinus angustifolius.

The amino acid sequence of the smaller subunit of conglutin gamma, the simplest of the three globulins from the seeds of Lupinus angustifolius cv. Uniwhite, has been determined. The subunit was homogeneous and contained 154 amino acid residues, including five sulphur-containing amino acids--a considerably higher content than is found in most other legume storage proteins. There was no indication of the complexity experienced in studies of many other legume storage proteins. This is perhaps the first sequence of a subunit of a legume storage protein to be determined.

Amino Acid Sequence↗